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Background: Proteins and anionic octenyl succinic anhydride (OSA)-modified starch (OSA-starch) are common ingredients in food systems. The interactions between OSA-starch and protein are found to alter the structural and functional properties of the protein-OSA-starch complexes. In this regard, the close understanding of the relationship among the molecular interactions between whey protein isolate (WPI) and OSA-high amylose corn starch (HAS), structure changes and rheological, digestibility and release properties of WPI-OSA-HAS was investigated., Results: The molecular interactions of WPI-OSA-HAS were significant for increasing the surface rough, solubility, storage modulus and loss modulus, but decreasing the R 1047/1022 values. For the nutritional evaluation, the anti-digestibility of WPI-OSA-HAS was enhanced with increased resistant starch + slowly digestible starch contents and decreased equilibrium hydrolysis percentage and kinetic constant. During the digestion, part of the starch granule, OSA groups and WPI were lost, but the loss was lower than for OSA-HAS. Furthermore, the results of curcumin-loaded WPI-OSA-HAS in simulated gastrointestinal fluids demonstrated that curcumin could be gradually released to simulate colonic fluid. Notably, the interaction between WPI and OSA-HAS depended on the WPI concentration with the stronger molecular interactions obtained at 35% concentration., Conclusion: These results provided important information concerning how to adjust the rheological, anti-digestibility and release properties of WPI-OSA-HAS through altering the electrostatic interactions and hydrophobic interactions of WPI-OSA-HAS. © 2024 Society of Chemical Industry., (© 2024 Society of Chemical Industry.)

Background: Algae oil has garnered widespread acclaim due as a result of its high purity of docosahexaenoic acid (DHA) and excellent safety profile. The present study aimed to develop stable nanoemulsions (NEs) systems containing DHA from algae oil through thermal sterilization by combining modified whey protein concentrate (WPC) with low methoxyl pectin (LMP), as well as to investigate the impact of LMP concentration on the thermal stability and the gastrointestinal delivery efficiency of DHA NEs., Results: The addition of LMP enhanced the stability of the emulsion after sterilization, at the same time as improving the protective and sustained release effects of DHA in the gastrointestinal tract. Optimal effect was achieved at a LMP concentration of 1% (10 g kg -1 sample), the stability of the emulsion after centrifugation increased by 17.21 ± 5.65% compared to the group without LMP, and the loss of DHA after sterilization decreased by only 0.92 ± 0.09%. Furthermore, the addition of 1% LMP resulted in a substantial reduction in the release of fatty acids from the NEs after gastrointestinal digestion simulation, achieving the desired sustained-release effect. However, excessive addition of 2% (20 g kg -1 sample) LMP negatively impacted all aspects of the NEs system, primarily because of the occurrence of depletion effects., Conclusion: The construction of the LMP/WPC-NEs system is conducive to the protection of DHA in algae oil and its sustained-release in the gastrointestinal tract. The results of the present study can provide reference guidance for the application of algae oil NEs in the food field. © 2024 Society of Chemical Industry., (© 2024 Society of Chemical Industry.)

Background: Biopolymer based water-in-oil-in-water double (W 1 /O/W 2 ) emulsion systems comprise a complex emulsion system that might be affected by several factors and the status at multiple phases. The present study investigated the physicochemical properties of W 1 /O/W 2 double emulsions with inner W 1 phase incorporated with various polysaccharides and the outer phase stabilized by whey protein isolate (WPI). Six different polysaccharides were selected as co-emulsifiers in the inner phase, and their effects on morphology, droplet size, zeta potential and rheology properties were evaluated. Furthermore, the impact of WPI/polysaccharide concentration and pH on the physicochemical properties and storage stability of the emulsions was compared., Results: Emulsions with an inner phase incorporated with xanthan gum and carrageenan exhibited better stability than others. Increasing the concentration of WPI enhanced the overall stability of the double emulsion, although it compromised the integrity of the internal W 1 /O interface. On the other hand, a 1.0% concentration of polysaccharide, specifically when carrageenan is used, slowed down droplet floating and coagulation. An acidic external aqueous phase (pH 4) led to larger and more uniform particle size distributions, as well as enhanced stability. The lower pH decreased the viscosity and delayed molecular exchange in the oil phase, thereby preserving the structure of the double emulsion., Conclusion: These findings contribute to a better understanding of the factors influencing the stability and properties of W 1 /O/W 2 double emulsions with addition of anionic polysaccharides in the inner water phase. © 2024 Society of Chemical Industry., (© 2024 Society of Chemical Industry.)

Background: Protein-polysaccharide complexes have been successfully used for emulsion stabilization. However, it is unclear how the complex's surface charge influences aggregation stability and coalescence stability of emulsions, and whether a low charged interfacial film can still maintain the coalescence stability of oil droplets. In the present study, the effects of pH (around the pI of protein) on the aggregation and coalescence stability of emulsions were investigated., Results: Whey protein isolate (WPI) and peach gum polysaccharides (PGP) complexes (WPI-PGP complexes) were synthesized at pH 3, 4 and 5. Their sizes were 598, 274 and 183 nm, respectively, and their ζ-potentials were +2.9, -8.6 and -22.8 mV, respectively. Interface rheological experiments showed that WPI-PGP complex at pH 3 had the lowest interfacial tension, and formed the softest film compared to the complexes at pH 4 and 5. Microfluidic experiments showed that all WPI-PGP complexes were able to stabilize droplets against coalescence within short timescales (milliseconds). At pH 3, no coalescence was observed even under conditions where the continuous phase flow influenced the shape of oil droplets (from spheres to ellipsoids). At pH 4 and 5, the model emulsions were stable over 16 days of storage, extensive aggregation and creaming occurred at pH 3 after 8 days. Importantly, no coalescence took place., Conclusion: The present study confirmed that the aggregation stability of the emulsions was mainly determined by the surface charge of the complex, whereas the coalescence stability of emulsions is expectedly determined by steric repulsion, providing new insights into how to prepare stable food emulsions. © 2024 Society of Chemical Industry., (© 2024 Society of Chemical Industry.)

Background: Whey protein isolate (WPI) generally represents poor functional properties such as thermal stability, emulsifying activity and antioxidant activity near its isoelectric point or high temperatures, which limit its application in the food industry. The preparation of WPI-polysaccharide covalent conjugates based on Maillard reaction is a promising method to improve the physical and chemical stability and functional properties of WPI. In this research, WPI-inulin conjugates were prepared through wet heating method and ultrasound method and their structural and functional properties were examined., Results: In conjugates, the free amino acid content was reduced, the high molecular bands were emerged at sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), new C-N bonds were formed in Fourier-transform infrared (FTIR) spectroscopy, and fluorescence intensity was reduced compared with WPI. Furthermore, the result of circular dichroism (CD) spectroscopy also showed that the secondary structure of conjugates was changed. Conjugates with ultrasound treatment had better structural properties compared with those prepared by wet heating treatment. The functional properties such as thermal stability, emulsifying activity index (EAI), emulsion stability (ES) and antioxidant activity of conjugates with wet heating treatment were significantly improved compared with WPI. The EAI and ES of conjugates with ultrasound treatment were the highest, but the thermal stability and antioxidant activity were only close to that of the conjugates with wet heating treatment for 2 h., Conclusion: This study revealed that WPI-inulin conjugates prepared with ultrasound or wet heating method not only changed the structural characteristics of WPI but also could promote its functional properties including thermal stability, EAI, ES and antioxidant activity. © 2024 Society of Chemical Industry., (© 2024 Society of Chemical Industry.)

In the cheese industry, whey, which is rich in lactose and proteins, is underutilized, causing adverse environmental impacts. The fractionation of its components, typically carried out through filtration membranes, faces operational challenges such as membrane fouling, significant protein loss during the process, and extended operating times. These challenges require attention and specific methods for optimization and to increase efficiency. A promising strategy to enhance industry efficiency and sustainability is the use of enzymatic pre-treatment with the enzyme transglutaminase (TGase). This enzyme plays a crucial role in protein modification, catalyzing covalent cross-links between lysine and glutamine residues, increasing the molecular weight of proteins, facilitating their retention on membranes, and contributing to the improvement of the quality of the final products. The aim of this study is to review the application of the enzyme TGase as a pretreatment in whey protein filtration. The scope involves assessing the enzyme's impact on whey protein properties and its relationship with process performance. It also aims to identify both the optimization of operational parameters and the enhancement of product characteristics. This study demonstrates that the application of TGase leads to improved performance in protein concentration, lactose permeation, and permeate flux rate during the filtration process. It also has the capacity to enhance protein solubility, viscosity, thermal stability, and protein gelation in whey. In this context, it is relevant for enhancing the characteristics of whey, thereby contributing to the production of higher quality final products in the food industry. © 2023 Society of Chemical Industry., (© 2023 Society of Chemical Industry.)

Background: Whey protein isolate (WPI) nanoparticles can be used in a strategy to improve the bioavailability of curcumin (CUR) although they are generally not stable. Previous studies have indicated that Tremella fuciformis polysaccharides (TFPs) can increase the stability of WPI. This work investigated systematically the characterization and structure of TFP/WPI nanoparticles with differing CUR content., Results: The highest encapsulation efficiency of CUR was 98.8% and the highest loading content was 47.88%. The TFP-WPI-CUR with 20 mg mL -1 of CUR had the largest particle size (653.67 ± 21.50 nm) and lowest zeta potential (-38.97 ± 2.51 mV), and the capacity to retain stability across a variety of salt ion and pH conditions for 21 days. According to the findings of the structural analysis, the addition of TFPs and CUR rendered the structure of WPI amorphous, and the β-sheet was reduced. Finally, in vitro release indicated that the TFP-WPI-CUR combination could regulate the sustained release behavior of CUR., Conclusion: In summary, TFP-WPI nanoparticles can be used as carriers for the delivery of CUR, and can expand applications of CUR in the functional food, dietary supplement, pharmaceutical, and beverage industries. © 2023 Society of Chemical Industry., (© 2023 Society of Chemical Industry.)

Background: Protein-pectin conjugates, obtained through a controlled Maillard reaction in blends of precursors, are studied for their contribution to improving the emulsifying and thermal properties of proteins. The objective was to obtain a conjugate between whey protein concentrate (WPC) and non-conventional pectins extracted in acid (acid tomato pectin, ATP) and aqueous medium (water tomato pectin, WTP) from industrialized tomato residues (tomato waste, TW), characterize the conjugates and study their emulsion properties. The Maillard reaction was carried out at 60 °C and 75% relative humidity in blends with 2:1 proportions; 1:1 and 1:2 (m protein :m pectin ) for 3, 6 and 12 days. Conjugates were compared concerning treated and untreated WPC., Results: The WPC-ATP conjugate showed significant increases in color difference (ΔE). The electrophoresis profile of the conjugates showed diffuse bands of molecular weight between 37 and 250 kDa and a reduction in the intensity of bands characteristic of WPC (α-lactalbumin and β-lactoglobulin). Thermal analysis showed an increase in the peak temperature and a reduction in the enthalpy change in protein denaturation, associated with the formation of conjugates. The infrared spectroscopy of the conjugates, in the amide III zone (1300-1100 cm -1 ), indicated an increase in the relative peak area associated with the unfolding and exhibition of the hydrophobic zones of the WPC fraction. The emulsions formulated with the conjugates showed a significant increase in the emulsifying stability index (ESI) (P < 0.05) concerning the treated and untreated WPC emulsions., Conclusion: The formation of conjugates increased the emulsifying properties and improved the thermal stability of WPC, showing an innovative and alternative food ingredient too. © 2023 Society of Chemical Industry., (© 2023 Society of Chemical Industry.)

Background: Whey protein-epigallocatechin gallate (WP-EGCG) covalent conjugates and non-covalent nanocomplexes were prepared and compared using Fourier-transform infrared spectra. The effect of pH (at 2.6, 6.2, 7.1, and 8.2) on the non-covalent nanocomplexes' functional properties and the WP-EGCG interactions were investigated by studying antioxidant activity, emulsification, fluorescence quenching, and molecular docking, respectively., Results: With the formation of non-covalent and covalent complexes, the amide band decreased; the -OH peak disappeared; the antioxidant activity of WP-EGCG non-covalent complexes was 2.59- and 2.61-times stronger than WP-EGCG covalent conjugates for 1-diphenyl-2-picryl-hydrazyl (DPPH) and ferric reducing ability of plasma (FRAP), respectively (particle size: 137 versus 370 nm). The antioxidant activity (DPPH 27.48-44.32%, FRAP 0.47-0.63) was stronger at pH 6.2-7.1 than at pH 2.6 and pH 8.2 (DPPH 19.50% and 26.36%, FRAP 0.39 and 0.41). Emulsification was highest (emulsifying activity index 181 m 2  g -1 , emulsifying stability index 107%) at pH 7.1. The interaction between whey protein (WP) and EGCG was stronger under neutral and weakly acidic conditions: K SV (5.11-8.95 × 10 2  L mol -1 ) and K q (5.11-8.95 × 10 10  L mol s -1 ) at pH 6.2-7.1. Binding constants (pH 6.2 and pH 7.1) increased with increasing temperature. Molecular docking suggested that hydrophobic interactions played key roles at pH 6.2 and pH 7.1 (∆H > 0, ∆S > 0). Hydrogen bonding was the dominant force at pH 2.6 and pH 8.2 (∆H < 0, ∆S < 0)., Conclusion: Environmental pH impacted the binding forces of WP-EGCG nanocomplexes. The interaction between WP and EGCG was stronger under neutral and weakly acidic conditions. Neutral and weakly acidic conditions are preferable for WP-EGCG non-covalent nanocomplex formation. © 2023 Society of Chemical Industry., (© 2023 Society of Chemical Industry.)

Background: Milk contains a massive class of minor proteins that are known for their various biological and molecular functions. Many whey proteins transfer the host defense mechanism to the human body. In this assay, electrophoresis followed by a high-resolution mass spectrometry-based proteomic approach has been applied to identify the whey proteome of Indian Jersey crossbreed bovines., Results: Two search engines, MS Amanda and Sequest HT, have shown more than 29 minor proteins. Chromosomal mapping revealed that chromosomes 5 and 9 are expressing maximum proteins in the whey proteome. The principal component analysis, outlier plots, scree plots, score plots, and loading plots were generated to further assess the results., Conclusion: The majorly expressed ones are glycosylation-dependent cell adhesion molecule-1, ubiquitin, desmoglein, annexin, glycoprotein, arginase, histones, peroxiredoxin, vimentin, desmin, catenin, peripherin, and 70 kDa heat shock protein. © 2023 Society of Chemical Industry., (© 2023 Society of Chemical Industry.)

Background: Protein-polysaccharide gels have significant and unique properties in food formulations. However, they are susceptible to environmental influences like heat and pH. The present work investigated the effects of acid and alkali treatments on the gel properties and microstructural changes of whey protein isolate (WPI) high acyl gellan gum (HG)., Results: The results showed that the pH had a strong effect on the gel hardness, water-holding capacity (WHC), free sulfhydryl groups (-SH), and other properties of the composite gel. The hardness reached a maximum level of 282.50 g and the best WHC was 98.33% at pH 7, indicating that a suitable pH could promote this cross-linking between the WPI and HG molecules. The rheological analysis demonstrated that the pH affected the gel formation time. Meanwhile, the gel formation time reached a maximum at pH 7, and the gel's storage modulus G' value was the largest in the final state. Fourier transform infrared spectroscopy (FTIR) results showed that pH affected the interaction between WPI and HG. Scanning electron microscopy (SEM) analysis also indicated that the composite gel formed a three-dimensional network structure at pH 7-9., Conclusion: These results could broaden the application of protein-polysaccharide gels in food and delivery systems. © 2023 Society of Chemical Industry., (© 2023 Society of Chemical Industry.)

Background: This research was aimed at the fabrication of jujube extract (JE)-loaded beads by extrusion, using whey protein isolate (WPI), chickpea protein concentrate (PPC) and a combination of two types of hydrocolloid insoluble fraction of Persian gum (IFPG) and sodium alginate (Al)., Results: JE-loaded beads with the highest encapsulation efficiency (10.87%) and polyphenol content (120.8 mg L -1 gallic acid) were obtained using Al-IFPG/PPC at 4 °C. The Al-IFPG, Al-IFPG/WPI and Al-IFPG/PPC beads revealed 5.66, 6.85 and 5.76 mm bead size, respectively, and almost all of them demonstrated a homogeneous and spherical structure. Fourier transform infrared spectroscopy data proved that the stable structure of the Al-IFPG beads was due to hydrogen bonding and electrostatic interactions. The thermostability of beads loaded with JE based on Al-IFPG/WPI was significantly enhanced compared to pure Al-IFPG. Texture evaluation of JE-loaded beads based on Al-IFPG incorporation with WPI revealed an increment in the hardness of beads., Conclusion: This study confirmed the potential of Al-IFPG complex beads for the effective delivery of jujube extract via incorporation into pea and whey proteins and for the expansion of its use in products. © 2023 Society of Chemical Industry., (© 2023 Society of Chemical Industry.)

Background: Chia oil (CO) is popular for being the richest vegetable source of α-linolenic acid (60-66%). However, this content of polyunsaturated fatty acids (PUFA) limits the incorporation of bulk CO in food products due to its high probability of oxidation. This justifies the study of alternative wall materials for microencapsulation. No reports regarding the use of dairy protein/vegetable protein/polysaccharide blends as wall material for the microencapsulation of CO have been published. Therefore, this work analyzed the behavior of a whey protein concentrate (WPC)/soy protein isolate (SPI)/arabic gum (AG) blend as wall material. The complex coacervation (CC) process was studied: pH, 4.0; total solid content, 30% w/v; WPC/SPI/AG ratio, 8:1:1 w/w/w; stirring speed, 600 rpm; time, 30 min; room temperature., Results: The oxidative stability index (OSI) of CO (3.25 ± 0.16 h) was significantly increased after microencapsulation (around four times higher). Furthermore, the well-known matrix-forming ability of AG and WPC helped increase the OSI of microencapsulated oils. Meanwhile, SPI contributed to the increase of the encapsulation efficiency due to its high viscosity. Enhanced properties were observed with CC: encapsulation efficiency (up to 79.88%), OSIs (from 11.25 to 12.52 h) and thermal stability of microcapsules given by the denaturation peak temperatures of WPC (from 77.12 to 86.00 °C). No significant differences were observed in the fatty acid composition of bulk and microencapsulated oils., Conclusion: Microcapsules developed from complex coacervates based on the ternary blend represent promising omega-3-rich carriers for being incorporated into functional foods., (© 2023 Society of Chemical Industry.)

Background: To overcome the limitations in the use of protein as an emulsifier, soy lecithin, a natural surfactant, was used along with whey protein isolate (WPI) to produce o/w emulsions containing cholecalciferol and α-tocopherol. The physical stability of the emulsions prepared with WPI and varying concentrations of lecithin (0, 1, 2, and 3% w/w) was measured in different heat, pH, and ionic-strength food environmental conditions., Results: All emulsions were shown to be less than 250 nm in size and less than 0.3 in polydispersity index (PDI). The morphology of the emulsions was spherical, and the droplets of the emulsion containing lecithin were thicker and larger than those of the emulsion without lecithin (WPI&#95;L0). After autoclaving, WPI&#95;L0 increased in size from 197.8 ± 1.7 nm to 528.5 ± 28.4 nm, and the retention of cholecalciferol and α-tocopherol decreased to 40.83 ± 0.63% and 49.68 ± 1.84%, respectively. At pH 5.5, near the isoelectric point of WPI, WPI&#95;L0 increased in size due to aggregation, but emulsions containing lecithin remained stable at a PDI under 0.3. Turbiscan stability index of the emulsion prepared with WPI and 3% lecithin was the lowest, indicating good storage stability. In addition, it was confirmed that the higher the lecithin content, the higher the viscosity, and the higher the amount of free fatty acids released in the in vitro digestion model., Conclusion: This study can provide theoretical evidence for enhancing the physical stability of protein emulsions by co-stabilization with lecithin, promoting their application in various foods. © 2022 Society of Chemical Industry., (© 2022 Society of Chemical Industry.)

Background: Walnut oil, which is rich in polyunsaturated fatty acids (PUFAs), can be incorporated into food emulsions to increase their nutritional value. However, these emulsions are highly susceptible to deterioration during storage due to lipid oxidation. Konjac glucomannan (KGM) is a neutral plant polysaccharide used as a stabilizer, thickener or gelling agent in foods. The goal of this study was to incorporate KGM into oil-in-water emulsions containing walnut oil droplets coated by whey protein isolate (WPI) and then determine its effects on their physical and oxidative stability., Results: At pH 3, inclusion of KGM (0.1-1 g kg -1 ) reduced the positive surface potential on the droplets in the emulsions and modified the secondary structure of the adsorbed whey proteins, suggesting an interaction between KGM and WPI at the droplet surfaces. The physical stability of the emulsions was enhanced when 0.1-0.6 g kg -1 KGM was added but reduced at higher levels. Lipid oxidation was inhibited in the emulsions in a dose-dependent manner when 0.2-0.6 g kg -1 KGM was added but protein oxidation was promoted at higher KGM levels. The steric hindrance provided by the thick WPI-KGM interfaces, as well as the ability of the polysaccharides to modify the antioxidant properties of the adsorbed proteins, may account for these effects., Conclusion: These results suggest that KGM can be used to inhibit lipid oxidation in emulsified foods containing protein-coated oil droplets. However, its level must be optimized because higher doses can result in droplet aggregation and protein oxidation. © 2022 Society of Chemical Industry., (© 2022 Society of Chemical Industry.)

Background: The meat industry is determined to find biodegradable packaging with properties similar to plastic. Furcellaran (FUR) and whey protein isolate (WPI) were used as a film matrix in which Borago officinalis extract (BOE) was incorporated as an antioxidant compound. The film's mechanical properties, water behavior, surface color, and antioxidant power were analyzed.Smoked hams were manufactured using two different types of film application: cured meat covered with film, smoked and cooked or hamsafter smoking, cooking and cooling. Smoked, vacuum packed ham was used as a control sample. The products were stored at 4 °C for 21 days and analyzed every 7 days., Results: The elongation at break (EAB) and tensile strength (TS) of FUR/WPI films without the extract were 6.30% and 20.59 MPa, respectively, and after incorporating BOE, the EAB and TS were 24.30% and 15.33 MPa, respectively. The films with BOE were darker and had greater antioxidant capacity. The water content and activity in the products with films decreased along with storage time while the control remained stable. The results of microbiological, oxidation product accumulation, and sensory analysis were comparable in all the products., Conclusions: The smoking time can be reduced due to the dark color of the hams covered with BOE film. The barrier properties of those films should be increased. Other parameters were comparable to plastic packaging. The films therefore have the potential to be used instead of plastic packaging in the meat industry. © 2020 Society of Chemical Industry., (© 2020 Society of Chemical Industry.)

Background: Maltose is an essential derivative of starch. To understand the processability and stability of maltose-containing foods, material characterization of the phase and state transition from its amorphous state is required. Although the crystallization of amorphous maltose is well understood, few studies have reported the relationship between the crystallization and the glass transition temperature (T g )-related molecular mobility. In this study, water sorption, crystallization, T g -related α-relaxation, and the corresponding time factor for amorphous maltose and maltose / whey protein isolate (WPI) mixtures are measured at various water activity (a w ) levels and 25 °C., Results: The water-additive principle for maltose / WPI mixtures was observed at a w  ≤ 0.440 at the molecular level, whereas the crystallization of amorphous maltose occurred at high a w values (≥0.534). The crystal formation and crystallization kinetics of amorphous maltose were affected by water and WPI at a w  ≥ 0.534 and 25 °C, as determined by X-ray diffraction. The relationship between T g and the water content was fitted by the Gordon-Taylor model, and its constant showed a compositional dependence for the maltose / WPI mixtures. The α-relaxation temperature of the amorphous samples decreased due to water plasticization, but increased with an increase in the WPI quantity. The Strength (S) value for amorphous maltose, which was a quantitative estimate of the compositional effects on molecular mobility, was based on the William-Landel-Ferry (WLF) equation., Conclusion: The S concept exhibits considerable potential for application in controlling the crystallization of amorphous maltose and improving the processability and stability of maltose-containing foods. © 2020 Society of Chemical Industry., (© 2020 Society of Chemical Industry.)

Background: Whey protein concentrate (WPC)/pullulan (PUL) hydrogel is applied as a microencapsulation wall material to protect probiotics. However, the interactions between WPC and PUL during gelation have not been clarified. In the present study, the effects of PUL concentration and pH on the interactions between WPC and PUL during gelation were evaluated with respect to appearance, zeta-potential, sulfhydryl group amount, surface hydrophobicity and infrared spectroscopy measurements. The rheological properties of WPC/PUL gels were also determined., Results: The results obtained showed that a proper concentration (0.40 g mL -1 ) of PUL could improve the gel by enhancing the strength of hydrogen bonding, electrostatic interactions and exposure of hydrophobic groups, whereas too much PUL inhibited the formation of disulfide bonds. Furthermore, hydrophobic interactions, disulfide bonds and hydrogen bonds were destroyed in varying degrees under an alkaline environment. The rheological results also demonstrated a similar effect of PUL concentration and pH on the storage modulus (G') of WPC/PUL gels., Conclusion: When the WPC/PUL gel was formed at PUL concentration of 0.40 g mL -1 and pH 7.0, the interaction between WPC and PUL could be enhanced, which is beneficial for the future application of WPC/PUL gels in the food industry. © 2020 Society of Chemical Industry., (© 2020 Society of Chemical Industry.)

Background: Genetic variants of β-casein are cosnidered to affect the components of milk. However, limited data are available on the bovine protein components correlated with β-casein variants at the proteome level. In the present study, cows producing milk containing β-casein variants (A1A1 and A2A2) and their heterozygote (A1A2) were identified using a high-resolution melting method, and milk samples were collected and tested. Comparative analyses of casein micelles, whey and milk fat globule membrane fractions in each milk variant were performed using a label-free proteomics approach., Results: The results obtained showed that ceruloplasmin and cathelicidin-2 were the most abundant proteins in milk containing variant A1A1; lactoferrin and CD5 molecule-like were the most abundant proteins in milk containing variant A2A2; and selenoprotein P and osteopontin were the most abundant proteins in milk containing heterozygote A1A2. Differences in protein components in milk containing the different β-casein variants were visualized using hierarchical clustering, and profiles were separated using principal components analysis. The differentially expressed proteins in milk containing A1A1, A2A2 or A1A2 were predominantly involved in response to stress and defense response according to their Gene Ontology annotations., Conclusion: Our findings provide new insights into differentially expressed milk proteins corresponding to the presence of different β-casein variants. This knowledge will help determine their potential biological functions in dairy products and the effects on human health. © 2020 Society of Chemical Industry., (© 2020 Society of Chemical Industry.)

Background: An ultrasonic spray nozzle was evaluated for the production of powders and microcapsules, using blueberry extract, modified starch (HI-CAP 100), and whey protein isolate (WPI). The effects of ultrasonic power and the concentration of coating materials on the characteristics of the resulting samples - such as viscosity, particle size, microencapsulation efficiency, color, glass transition temperature, Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), and morphology - were also studied., Results: The apparent viscosity was primarily affected by the self-heating of the ultrasonic nozzle as the power increased. The largest mean particle size of samples was observed under conditions of 30% coating concentration at 10 W. Glass transition temperatures (T g ) of the samples were affected by all atomization parameters significantly (P < 0.05) and the highest T g values of all samples were determined when the coating concentration was maximum (30%) and power level was minimum (5 W). The FTIR and XRD results indicate that the power of the ultrasonic nozzle did not cause any change in WPI structure and led to only a small change in the structure of HI-CAP 100 at 10 W. The short atomization time preserved, to some extent, the properties of the coating materials and the blueberry extract. With regard to the morphological properties, it was observed that the samples obtained with WPI showed less shrinkage than HI-CAP 100., Conclusion: The results indicated that an ultrasonic nozzle could be used successfully to prepare the blueberry microcapsule with HI-CAP 100 and WPI as coating materials. This study may contribute to the development of ultrasonic nozzle applications using different coatings for the microencapsulation of high-quality functional materials. © 2020 Society of Chemical Industry., (© 2020 Society of Chemical Industry.)

Background: The adsorption of proteins at oil/water interfaces can reduce interfacial tension and increase emulsion stability. However, emulsions stabilized by soy protein isolate (SPI) are not sufficiently stable. Using SPI as a control, a theoretical basis for the adsorption behavior of mixed SPI and whey protein isolate (WPI) at the oil/water interface was established and the effects of the protein ratio and content on the emulsion stability were studied., Results: Compared to SPI solution, SPI-WPI mixed solutions were found to reduce the size distribution of emulsion droplets and significantly improve the emulsion stability. Among the studied protein contents and ratios, the protein content of 0.2 g kg -1 and SPI/WPI mass ratio of 1:9 offered the lowest creaming stability index (15%), the smallest droplet size (278 nm), and the largest absolute value ζ-potential (35 mV), i.e. the emulsion stability was excellent. The largest dilatational modulus (10.08 mN m -1 ), dilatational elasticity (10.01 mN m -1 ), and dilatational viscosity (1.18 mN m -1 ), were observed with a protein content of 0.15 g kg -1 (SPI/WPI ratio of 1:9), along with a high interfacial protein adsorption capacity (47.33%). SPI-WPI complexes form a thick adsorption layer around oil droplets, resulting in an increase of the expansion modulus of the interfacial layer., Conclusion: SPI-WPI complexes can form a thick adsorption layer around oil droplets, resulting in increased expansion modulus of the interfacial layer, which improves emulsion stability. © 2020 Society of Chemical Industry., (© 2020 Society of Chemical Industry.)

Background: Consumption of Spirulina-based functionalized food is usually unpleasant due to its specific sensorial properties. Therefore, Spirulina was encapsulated using alginate and whey protein concentrate (WPC) by emulsification method, and the effect of adding free and microencapsulated Spirulina (MS) to non-fat stirred yogurt was investigated during storage., Results: Scanning electron microscope investigated microcapsules morphology and their mean particle size that was 52 μm, and electrostatic interaction between wall materials was illustrated by Fourier- transform infrared spectroscopy. The microspheres had appropriate encapsulation efficiency (44.54 ± 0.06%). Complete release of Spirulina from the microcapsules was observed in simulated intestinal fluid, which is favorable for Lactobacillus growth in human intestinal tract. Encapsulation caused meaningful differences in colorimetric factors, markedly in L*. Moreover, free and MS were added to yogurt samples, and the results showed that the physicochemical properties (pH, color, viscosity, water holding capacity and susceptibility to syneresis) and sensorial assessment of MS yogurt were positively affected. During the storage, MS yogurt had higher pH value than the others; furthermore, it showed the lowest syneresis and a constant increase in viscosity. Finally, the sensory evaluation results of MS yogurt, in comparison with the free form of Spirulina utilization, indicated improved acceptance of the produced functional food., Conclusion: Results showed an obvious impact of encapsulation on the physicochemical properties of yogurt containing MS. The sensory evaluation showed that encapsulation could generally enhance the customer's satisfaction. It can be stated that masking microalgae color and flavor by microencapsulation could be used for dairy products fortification by microalgae. © 2020 Society of Chemical Industry., (© 2020 Society of Chemical Industry.)

Background: Innovative approaches to combine whey with other ingredients and the use of new techniques in product development should be explored to meet consumers' needs and expectations. However, the question arises here of whether whey protein could be used as a suitable food matrix for supplementation with β-glucan, an attractive glucose polymer and a physiologically functional component. The present study addresses the challenge associated with the design and characterization of whey protein spread as a substrate for β-glucan delivery. The results are discussed on the basis of physical-chemical and microbiological characteristics, which are subsequently linked to its sensorial profile., Results: A whey protein spread can be developed without the addition of NaCl, with physicochemical characteristics (pH, viscosity), microbiological counts, and sensory acceptance (color, aroma, overall impression) similar to the product with NaCl. This spread can be refrigerated for 28 days. The whey protein spread presented high whey protein content (18.67-19.17 g 100 g -1 ) and could be a good source of carbohydrates (8.30-8.68 g 100 g -1 ), with low levels of fat (0.2 g 100 g -1 ) and lactose (1.56-1.61 g 100 g -1 ). The sensorial results showed that women would prefer a product with lower salt content., Conclusion: This is the first study to evaluate the development of a whey protein spread enriched with β-glucan, providing results that are of interest for the dairy sector. The combination of whey and β-glucan can be explored industrially as a whey protein spread, with satisfactory results for physicochemical, microbiological, and sensory acceptance. © 2019 Society of Chemical Industry., (© 2019 Society of Chemical Industry.)

Background: Diacylglycerol (DAG) reduces body weight, suppresses body fat accumulation, and lowers the blood lipid concentration, and docosahexaenoic acid (DHA) can reduce the risk of occurrence of coronary artery diseases., Results: DAG-rich algae oil with a high DHA content (55.9%) was synthesized via the lipase-catalyzed glycerolysis of algae oil, which consisted of triacylglycerol (43.9 mol%), DAG (40.9 mol%), and monoacylglycerol (15.2 mol%). The DAG-rich algae oil-in-water emulsions were prepared using three emulsifiers [whey protein concentrate (WPC), Tween80, and Tween80 + Span80]. The WPC-emulsion formed a thicker serum layer (6.67% at day 51) and larger oil droplets (d 32 , 0.37 μm at day 28) than the Tween80- and Tween80 + Span80-emulsions (3.33-4.17%; 0.26 μm), and an upper cream layer with excess oil droplets was observed in only the WPC-emulsion, indicating that WPC-emulsion possesses the lowest emulsification stability. The hydroperoxide value and reduction rate of the DHA content were higher in the WPC-emulsions than in the Tween80- and Tween80 + Span80-emulsions during storage, which suggested that the WPC-emulsion had the lowest oxidation stability., Conclusion: The DAG-rich algae oil-in-water emulsion prepared with suitable emulsifiers, such as non-ionic emulsifiers, would have excellent emulsification and oxidative stabilities and provides a health benefit for special purposes in the food processing industry. © 2019 Society of Chemical Industry., (© 2019 Society of Chemical Industry.)

Background: The functional properties of whey protein isolate (WPI) are sensitive to pH, ionic strength, and temperature. This prevents its application in various food systems and processing technologies. The conjugation of proteins with polysaccharides via the Maillard reaction is an efficient method to improve the functionality of proteins. The purpose of this work was to conjugate gum acacia (GA) with WPI via the dry-heating Maillard reaction and to investigate the effect of reaction time on the physicochemical and functional properties of WPI-GA conjugates., Results: Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and high-performance size exclusion chromatography confirmed the formation of higher molecular weight conjugates. The degrees of glycation for WPI-GA conjugates incubated for 1, 3, 5, and 7 days were 28.14%, 44.98%, 49.50%, and 51.20%, respectively. The glycation reaction reduced the surface hydrophobicity and fluorescence intensity of WPI significantly (P < 0.05). Functional properties of the conjugates, such as solubility, stability against heat-induced insolubility, and emulsion properties were all superior to the control WPI. However, a reaction time longer than a day resulted in a high degree of browning and decreased the functionality of the conjugate significantly (P < 0.05)., Conclusion: The results indicated that conjugation of WPI with GA can be a promising way to enhance its functional properties. However, the reaction time suitable for producing conjugates with superior functional properties was not necessarily the highest glycation degree that could be reached. © 2019 Society of Chemical Industry., (© 2019 Society of Chemical Industry.)

Background: The combined effect of variously chemically modified lotus rhizome starch, whey protein concentrate, psyllium husk and glycerol was evaluated on developed biodegradable films., Results: Dual-modified lotus rhizome starch composite films presented minimum solubility and water vapor permeability and maximum tensile strength among native and modified starch composite films. Elongation at break of dual-modified starch composite films (FLCOS 1 , FLCOS 2 ) was found to be a maximum, whereas a decrease was observed for FLCOS 3 . Oxidized lotus rhizome starch composite films were the most transparent among native and modified starch composite films, whereas crosslinked lotus rhizome starch composite films were the least transparent. Scanning electron microscopy indicated a homogeneous compact surface of oxidized starch composite films, whereas troughs were observed in crosslinked and dual-modified starch composite films. Using whey protein concentrate, psyllium husk and glycerol without any phase separation, smoother films and with compact microstructures were produced. Fourier transform infrared analysis revealed additional peaks for modified starch films, confirming greater interaction among starch and film-forming components, whereas amorphous structure was indicated from X-ray diffraction results of modified starch composite films., Conclusions: Owing to various properties of modified starches, these films find application in edible contact packages and can better be used for products where higher structural integrity and lower water vapor transmission are needed. © 2019 Society of Chemical Industry., (© 2019 Society of Chemical Industry.)

Background: One possible way to modify the emulsifying properties of whey proteins is by enzymatic hydrolysis. However, most studies covering the influence of the hydrolysis on whey proteins used a heating step (>65 °C) to inactivate the enzyme. This leads to irreversible product changes, like protein denaturation and increased viscosity. Here, the objective was to investigate the single effect of hydrolysis on the emulsifying properties of whey proteins under conditions without a temperature step for enzyme inactivation. Therefore, two acidic peptidase preparations (Maxipro AFP, Protease AP-30L) differing in their peptidase composition were investigated and applied at 45 °C and pH 2.75. The enzyme inactivation was realized by a simple shift to pH 7.0., Results: After the pH shift, no activity or further hydrolysis was measurable. For the products, no differences (assuming P > 0.05) regarding the emulsifying properties were detected between the two peptidase preparations used. The emulsifying properties of the whey protein isolate hydrolysates produced increased (i.e. half-life >71%) until a degree of hydrolysis of 1.1%. This indicated that the endopeptidase (aspergillopepsin I) present in both preparations was determining the emulsifying properties. As a plus, the presence of exopeptidases in Protease AP-30L compared with Maxipro AFP reduced the bitterness of the hydrolysate (-50%)., Conclusion: The application of acidic endo- and exopeptidases enables the production of emulsifying whey protein isolate hydrolysates at high protein concentrations (≥10%) without a commonly used heat inactivation step. The presence of exopeptidases in acidic peptidase preparations is favorable, due to the improved taste. © 2019 Society of Chemical Industry., (© 2019 Society of Chemical Industry.)

Background: Interest in supplementing food with iron to counteract dietary deficiencies has been on the rise in recent years. A major challenge is the pro-oxidant activity of soluble iron, which compromises the chemical stability of the enriched food products. This problem could be mitigated by encapsulating iron, to physically keep it separated from oxidizable substrates, such as unsaturated fatty acids. In the present work, the physical and chemical stability of surfactant- or protein-stabilized oil-in-water emulsions fortified with iron was investigated., Results: Iron (ferrous sulfate) was successfully incorporated in liposomes at high encapsulation efficiency (89%). The liposomes obtained were added to emulsions stabilized with either Tween 20 or whey protein isolate (WPI), and its oxidative stability was monitored and compared with emulsions with free iron. Tween 20-stabilized emulsions were more stable against oxidation than WPI-stabilized emulsions, and furthermore lipid oxidation was substantially higher in emulsions containing iron (either free, or encapsulated in liposomes) than in blank emulsions. This shows that liposomal encapsulation did not inhibit the pro-oxidant activity of iron., Conclusion: Despite the high encapsulation efficiency of iron in our liposomes, these systems are not suitable to supplement model foods with iron because of the associated deleterious chemical reactivity. This is most probably due to the phospholipids used as encapsulation material being prone to oxidation, which may actively contribute to the oxidative process. These aspects are normally not taken into account but we showed that they are of utmost importance, and should be taken as a starting point in the design of delivery systems. © 2018 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry., (© 2018 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.)

Background: RuBisCO was extracted from sugar beet leaves using soft and food-compatible technologies. Proximate composition, solubility, emulsifying, foaming and gelling properties of the protein isolate were determined. All these properties were systematically benchmarked against commercial whey and soy protein isolates used in food applications., Results: RuBisCO protein isolate (RPI) contained 930 g kg -1 of crude protein. Protein solubility was higher than 80% at pH values lower than 4.0 or higher than 5.5. Foaming capacity of RPI was better at pH 4.0 than at pH 7.0. Interestingly, 10 g kg -1 protein foams were more stable (pH 7.0 and 4.0) than foams obtained with whey or soy protein. Moreover, 10 g kg -1 RPI emulsions at pH 4.0 or 7.0 exhibited good stability, being similar to whey protein isolate. Remarkable gelling properties were observed at pH 7.0, where 50 g kg -1 protein solutions of RPI formed self-supporting gels while more concentrated solutions were needed for whey or soy protein., Conclusion: RuBisCO showed comparable or superior functional properties to those of currently used whey and soy protein isolates. These results highlight the high potential of sugar beet leaf protein isolate as a nutritious and functional food ingredient to face global food security and protein supply. © 2018 Society of Chemical Industry., (© 2018 Society of Chemical Industry.)

Background: Effects of pH (6-8), protein concentration (60-110, g kg -1 ), heating temperature (70-95 °C) and time (5-30 min) on physiochemical and rheological properties of thermal-induced polymerized whey protein isolate (PWP) were systematically investigated. Degree of denaturation, particle size, zeta potential, free sulfhydryl group content, surface hydrophobicity and apparent viscosity were determined., Results: Heating whey protein above 75 °C at pH 7 or 8 resulted in denaturation of 80-90% whey protein. pH variation had a remarkable influence on particle size of samples (P < 0.05), whereas heating temperature and time did not generate significant changes. Zeta potential of PWP samples fell in the range of -30 to -40 mV. Free sulfhydryl group content of PWP samples decreased with increasing level regarding each factor. Surface hydrophobicity analysis showed that samples at higher pH or concentration became less hydrophobic, and increasing heating temperature or time resulted in higher hydrophobicity index. Time sweep test revealed that increasing protein concentration, heating temperature or time led to higher apparent viscosity. Flow behavior of PWP samples approached Newtonian character as protein concentration, heating temperature or time decreased., Conclusion: Systematic data may provide helpful information in designing a heating process for dairy products and application of PWP in the food industry. © 2018 Society of Chemical Industry., (© 2018 Society of Chemical Industry.)

Background: The current study aimed to prepare antimicrobial agents for food preservation from crude cheese whey. Crude cheese whey was digested with porcine pepsin, and calf and fungal rennets at various pHs. The digests were assessed for antibacterial activities against Escherichia coli and Bacillus subtilis., Results: The calf rennet digest at pH 3.0 showed the highest antibacterial activity. Three antibacterial peptides that acted against B. subtilis lactoferrin f(20-30), and β-lactoglobulin f(14-22) and f(92-103) were identified in the calf rennet digest. Only lactoferrin f(20-30) also exerted bactericidal activity against E. coli. LC-MS/MS analysis revealed that the three peptides were generated by the porcine pepsin at pH 2.5, whereas the calf rennet generated them at a wider pH (pH 2.5-3.5). Fungal rennet generated only β-lactoglobulin f 14-22 at pH 3.5. The pepsin and calf rennet digests at pH 2.5 and 3.0, respectively, reduced the E. coli and B. subtilis populations by approximately 2 log at 6000 µg mL -1 in milk at 4 °C., Conclusion: The calf rennet and porcine pepsin digests of cheese whey, at a specific acidic pH, which can be prepared from food-grade materials, have the potential to be used as natural food preservatives due to the presence of the three antibacterial peptides. © 2018 Society of Chemical Industry., (© 2018 Society of Chemical Industry.)

Background: The effect of marinating beef in acid whey on the antioxidant peptides generated, and their influence on lipid oxidation, colour stability, sensory analysis and protein degradation products in uncured roasted beef stored 6 weeks in vacuum conditions (T = 4 °C) were determined. Measurements of pHe, water activity, oxidation-reduction potential, colour, TBARS, the cutting force, texture and amino acid profile, the total content of peptides, and antioxidant activity of isolated peptides were conducted immediately after production and during 42 days of storage., Results: The non-nitrite control batch (C) was characterized by a lower a* value (6.33-6.70) during the whole storage period compared to the non-nitrite sample with acid whey (W). It also appears that meat with the worst colour stability has the poorest oxidative stability (C = 1.57 mg MDA kg -1 , W = 0.76 mg MDA kg -1 ). Activity against reactive forms of oxygen to fraction A and fraction B (P < 0.05) showed an increasing trend with time and it was the largest in sample C and W., Conclusion: The results indicated that bioactive peptides could be generated in uncured roasted beef. The <3.5 kDa peptides have strong antioxidant activity, as a result of which they function as inhibitors of lipid oxidation and colour discoloration during prolonged storage. © 2018 Society of Chemical Industry., (© 2018 Society of Chemical Industry.)

Background: The aim of this study was to investigate the effects of ultrasound applied at various powers (0, 200, 400, 600 or 800 W) and for different times (20 or 40 min) on the physico-chemical, functional properties and antioxidant activities of whey protein isolate (WPI) dispersions in the presence of 1.20 mmol L -1 calcium lactate., Results: Surface hydrophobicity and free sulfhydryl group of the WPI dispersions containing 1.2 mmol L -1 calcium lactate were significantly enhanced after sonication. Furthermore, particle size of WPI dispersions containing 1.20 mmol L -1 calcium lactate was minimised after sonication. Scanning electron microscopy of sonicated WPI suspensions containing 1.20 mmol L -1 calcium lactate showed that WPI microstructure had significantly changed. After WPI dispersions were treated by sonication assisted with calcium lactate, its gel strength enhanced and solubility decreased. Gel strength of sonicated WPI dispersions (600 W, 40 min) was the maximum among all the WPI treatments. Emulsification activity of sonicated WPI dispersions reduced while its emulsion stability increased. The DPPH radical scavenging activity and ferrous reducing power of sonicated WPI dispersions mostly increased., Conclusion: Ultrasound treatments induced structural changes in WPI molecules, leading to different microstructure and improved gel strength of WPI in the presence of calcium lactate. © 2017 Society of Chemical Industry., (© 2017 Society of Chemical Industry.)

Background: A dynamic gastrointestinal simulator, simgi ® , has been applied to assess the gastric digestion of a whey protein concentrate. Samples collected from the outlet of the stomach have been compared to those resulting from the static digestion protocol INFOGEST developed on the basis of physiologically inferred conditions., Results: Progress of digestion was followed by SDS-PAGE and LC-MS/MS. By SDS-PAGE, serum albumin and α-lactalbumin were no longer detectable at 30 and 60 min, respectively. On the contrary, β-lactoglobulin was visible up to 120 min, although in decreasing concentrations in the dynamic model due to the gastric emptying and the addition of gastric fluids. Moreover, β-lactoglobulin was partly hydrolysed by pepsin probably due to the presence of heat-denatured forms and the peptides released using both digestion models were similar. Under dynamic conditions, a stepwise increase in number of peptides over time was observed, while the static protocol generated a high number of peptides from the beginning of digestion., Conclusion: Whey protein digestion products using a dynamic stomach are consistent with those generated with the static protocol but the kinetic behaviour of the peptide profile emphasises the effect of the sequential pepsin addition, peristaltic shaking, and gastric emptying on protein digestibility. © 2017 Society of Chemical Industry., (© 2017 Society of Chemical Industry.)

Background: Large amounts of honey and liquid whey derived from the dairy industry are produced in Argentina. Honey is exported in bulk and whey is transformed into whey protein concentrates and isolates. The objective of this work was to investigate the effect of pH, composition and storage time on the properties of dried gels with honey, whey proteins and hydrocolloids., Results: Color properties varied according to pH and composition. The fracture stress of dried gels prepared with corn starch was higher than that of gels prepared with guar gum in all conditions assayed. Young's modulus was higher at pH 7 for both compositions and increased with storage time. Rubbery characteristics were found in dried gels with guar gum, while both corn starch and guar gum made the microstructure rougher. Multivariate analysis showed that samples could be grouped by pH. Panelists preferred pH 7 products over acidic ones, and no significant differences in sensory properties were found using either corn starch or guar gum in the formulation., Conclusion: The results demonstrated that it is possible to generate a new product, which may open new applications for honey and whey in food formulations. © 2017 Society of Chemical Industry., (© 2017 Society of Chemical Industry.)

Background: The production/characterization of nanocomposites based on whey protein concentrate (WPC) and montmorillonite (MMT) with lycopene as functional substance is presented and their potential use as alternative biomaterials in foodstuff applications is discussed. A full factorial design with varying levels of MMT (0 and 20 g kg -1 ) and lycopene (0, 60 and 120 g kg -1 ) was used. The mechanical properties (tensile and puncture tests), thermal stability, Fourier transform infrared vibrational spectra and film morphology of the resulting materials were evaluated., Results: Lycopene and MMT nanoparticles could be successfully included in WPC films using the casting/evaporation method. The films were flexible and homogeneous and a uniform dispersion of the components was achieved., Conclusion: Inclusion of 20 g kg -1 of MMT in the polymeric matrix improved both mechanical and thermal properties. Lycopene at the tested concentrations, besides its red coloring ability, did not promote any detectable interference in the structural or physical properties. These findings are important in devising applications and open a new perspective on the use of these materials in bioactive packaging processing. © 2017 Society of Chemical Industry., (© 2017 Society of Chemical Industry.)

Background: The use of biodegradable polymeric materials has been proposed as an environmentally-friendly alternative to petroleum-based packaging. To extend the shelf life of food products, these bioplastics must possess appropriate barrier properties and food-package stability. In the present study, shelf life analysis of packaged baby formula in biopolymeric, multilayer film, fabricated from poly(lactide) (PLA) and whey protein isolate (WPI), PLA/WPI/PLA and PLA pouches was performed at 4-35  o C and 50-59% relative humidity., Results: Despite the possible sorption of food components into contact PLA surfaces, the results demonstated that the transparency and barrier properties of PLA-based pouches were insignificantly changed over time (P > 0.05), although the films showed a slow rate of color change. The baby formula packaged in PLA/WPI/PLA had a delayed lipid oxidation compared to the sample in the PLA pouch, especially at a higher temperature. The application of WPI in the multilayer structure shifted the shelf life determination factor from lipid oxidation to moisture gain., Conclusion: The results indicate that the PLA/WPI/PLA pouch has good storage stability. The film could be used to package dry food properly at 4-35  o C and 50-59% relative humidity for an extended period of time. © 2016 Society of Chemical Industry., (© 2016 Society of Chemical Industry.)

Background: Polymerized whey protein-sodium tripolyphosphate can be induced to gel in an acidic environment provided during fermentation. The variety of thickening agent has an influence on texture that is an essential aspect of yogurt quality affecting consumer preference. Similar to polysaccharide stabilizers, the cold gelation properties of whey proteins can improve the body texture of yogurt products. Polymerized whey protein-sodium tripolyphosphate could be a favorable and interesting thickening agent for making set yogurt., Results: The effects of whey protein isolate (WPI), heat-treated whey protein-sodium tripolyphosphate (WPI-STPP), heat-treated WPI and pectin on the storage properties and microstructure of yogurt were investigated. All samples were analyzed for syneresis, pH, titratable acidity, viscosity, texture profile and microstructure during storage. The results showed that incorporating heat-treated WPI-STPP had a significant impact on syneresis (32.22 ± 0.60), viscosity (10 956.67 ± 962.1) and hardness (209.24 ± 12.48) (p < 0.05) with uniform body texture., Conclusion: Yogurt fermented with modified WPI-STPP had higher levels of protein and better hardness compared with yogurt using pectin. The microstructure was observed to be a uniform and denser, complicated network. Heat-treated WPI-STPP may be useful for improving yogurt texture. © 2016 Society of Chemical Industry., (© 2016 Society of Chemical Industry.)

Background: Chitosan was reported to interact with proteins through electrostatic interactions. Their interaction was influenced by pH, which was not fully characterized. Further research on the interactions between protein and chitosan at different pH and their influence on the thermal denaturation of proteins is necessary., Results: In this research, the effect of chitosan on the heat stability of whey protein solution at pH 4.0-6.0 was studied. At pH 4.0, a small amount chitosan was able to prevent the heat-induced denaturation and aggregation of whey protein molecules. At higher pH values (5.5 and 6.0), whey proteins complexed with chitosan through electrostatic attraction. The formation of chitosan-whey protein complexes at pH 5.5 improved the heat stability of dispersions and no precipitation could be detected up to 20 days. The dispersion with a medium amount of chitosan (chitosan:whey protein 1:5) produced the most stable particles, which had an average radius of 135 ± 14 nm and a zeta potential value of 36 ± 1 mV. In contrast, at pH 6.0 only the dispersion with a high amount of chitosan (chitosan:whey protein 1:2) showed good shelf stability up to 20 days., Conclusions: It was possible to produce heat-stable whey protein beverages by regulating the interaction between chitosan and whey protein molecules. © 2016 Society of Chemical Industry., (© 2016 Society of Chemical Industry.)

Background: Starch and whey protein isolate and their mixtures were used for making edible films. Moisture sorption isotherms, water vapour permeability, sorption of aroma compounds, microstructure, water contact angle and surface properties were investigated., Results: With increasing protein content, the microstructure changes became more homogeneous. The water vapour permeability increases with both the humidity gradient and the starch content. For all films, the hygroscopicity increases with starch content. Surface properties change according to the starch/whey protein ratio and are mainly related to the polar component of the surface tension. Films composed of 80% starch and 20% whey proteins have more hydrophobic surfaces than the other films due to specific interactions., Conclusions: The effect of carbohydrate/protein ratio significantly influences the microstructure, the surface wettability and the barrier properties of wheat starch-whey protein blend films. © 2016 Society of Chemical Industry., (© 2016 Society of Chemical Industry.)

Background: Transglutaminase (TGase) modifies milk proteins by cross-linking of caseins, with increased cheese yield being the main technological benefit. In the present work the influence of TGase addition in different concentrations (0, 1, 2 and 3 U g(-1) protein in the system) and under different incubation conditions (0 h, 40 °C/2 h, 25 °C/4 h and 5 °C/16 h) on the rennet coagulation time (RCT) and the comprehensive rennet gel properties were investigated., Results: Modification of milk proteins by TGase in a concentration-dependent manner caused longer RCT and lower gel firmness. The highest TGase concentration and incubation at 40 °C for 2 h resulted in the longest RCT and the lowest gel firmness. Rennet gels obtained from TGase modified milk were characterised by significantly lower values of texture parameters, lower syneresis and were composed of smaller casein micelles, thinner chains and smaller clusters than those obtained from the control milk. The content of whey proteins in the gel from modified milk was higher and the content of individual casein fractions in the milk samples and rennet gels decreased upon TGase modification., Conclusion: Rennet cheese with modified textural and nutritional properties and improved yield can be obtained upon TGase modification but simultaneous addition of rennet and TGase is recommended. © 2015 Society of Chemical Industry., (© 2015 Society of Chemical Industry.)

Background: Rice bran protein (RBP) is a valuable plant protein which has unique nutritional and hypoallergenic properties. Whey proteins have wide applications in the food industry, such as in dairy, meat and bakery products., Results: Whey protein concentrate (WPC), RBP and their mixtures at different ratios (1:1, 1:2, 1:5 and 1:10 w/w) were heated from 20 to 90 °C at different heating rates (0.5, 1, 5 and 10 °C min(-1) ). The storage modulus (G') and gelling point (Tgel ) of WPC were higher than those of RBP, indicating the good ability of WPC to develop stiffer networks. By increasing the proportion of WPC in mixed systems, G' was increased and Tgel was reduced. Nevertheless, the elasticity of all binary mixtures was lower than that of WPC alone. Tgel and the final G' of RBP-WPC blends were increased by raising the heating rate. The RBP-WPC mixtures developed more elastic gels than RBP alone at different heating rates. RBP had a fibrillar and lentil-like structure whose fibril assembly had smaller structures than those of WPC., Conclusion: The gelling structure of the mixed gel of WPC-RBP was improved by adding WPC. Indeed, by adding WPC, gels tended to show syneresis and had lower water-holding capacity. Furthermore, the gel structure was produced by adding WPC to the non-gelling RBP, which is compatible with whey and can be applied as a functional food for infants and/or adults. © 2015 Society of Chemical Industry., (© 2015 Society of Chemical Industry.)

Background: In animal care and management, there is an increasing demand for convenient methods of oral delivery of bioactive compounds to specific segments of an animal's gastrointestinal tract. The objective of this study was to test the suitability of microcapsules made with alginate and whey proteins of two different sizes (250 and 800 µm; containing 72 and 76 g kg(-1) of carvacrol respectively) for intestinal delivery of carvacrol in pigs., Results: Encapsulated carvacrol was completely released from the microcapsules after 5 h incubation in simulated intestinal fluids or 6 h in (ex vivo) ileal digesta, whereas release in simulated gastric fluid was minimal. Tests with growing pigs showed over 95% of unencapsulated carvacrol was absorbed or metabolized in the stomach and the duodenum. Encapsulation effectively minimized carvacrol absorption in the stomach (P < 0.05), and increased carvacrol recovery in the small intestine (P < 0.05). Encapsulated carvacrol was completely released from both small and large size capsules within the gastrointestinal tract of pigs. Larger size microcapsules showed a slower in vitro release and greater in vivo recovery of carvacrol in the small intestine (P < 0.05) than the smaller ones., Conclusion: This study indicates alginate-whey protein microencapsulation is a feasible approach for targeted oral delivery of hydrophobic compounds to pig intestines; increasing capsule size increased delivery of carvacrol to the end of the small intestine. © 2015 Her Majesty the Queen in Right of Canada Journal of the Science of Food and Agriculture © 2015 Society of Chemical Industry., (© 2015 Her Majesty the Queen in Right of Canada Journal of the Science of Food and Agriculture © 2015 Society of Chemical Industry.)