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This study aimed to hydrolyze lentil protein from two hydrolysis stages: single and sequential hydrolysis using Alcalase (1, 2, and 4% w/w enzyme to substrate (E:S)) and Flavourzyme (2% w/w) through a processing time of 180 min with an interval of 30 min, and then, degree of hydrolysis (DH), antioxidant and angiotensin-converting enzyme (ACE)-inhibitory activities, phenolic compounds, amino acid composition, molecular weight (MW) distribution, molecular weight profile, sensory, and functional properties were evaluated. The highest DH (47.05%), ACE-inhibitory (0.25 mg/mL), and phenolic compounds (3.84 mg GAE/g) were obtained when sequential hydrolysis was accomplished at Alcalase and Flavourzyme concentrations of 2% w/w and hydrolysis time of 120 and 60 min, respectively. Hydrolysis did not change the main amino acid profile. Despite this, the amino acids which contribute to umami taste were increased after hydrolysis. According to Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) results, the lowest MW peptides were produced by sequential hydrolysis which was agreed by gel permeation chromatography (GPC) (4.4 kDa and 100 Da). Sensorial analysis indicated that peptides produced by Alcalase at 1% w/w concentration with hydrolysis time of 180 min (Al-1%-180 min, DH value of 15.72%) had the highest bitter taste and further hydrolysis led to reduction of bitter taste and sweetness was increased for Flavourzyme (Fl-2%-180 min) and also sequential hydrolysis produced peptides. Alcalase digests indicated higher solubility than control and Flavourzyme digest. The emulsifying activity index (EAI) was decreased (35.2 to 21.5%) while Foaming capacity (FC) was increased (80 to 104.76%) by Alcalase hydrolysis.

In this study, kefiran was esterified with octenyl succinic anhydride (OSA). The esterification reaction variables including pH (8.5), kefiran concentration (5% (w/w)), OSA concentration (12% (w/w)), temperature (~38 °C) and reaction time (~80 min) were found as optimum points to achieve the maximum degree of substitution (DS) (0.041 ± 0.002). Kefiran-OSA samples with DS of 0.021 (FDA suggested DS) and 0.041 (maximum DS) were prepared and compared with unmodified kefiran in all experiments. FTIR and 1H NMR spectroscopies proved the grafting of OSA on kefiran structure. XRD analysis revealed that with increase in DS, the physical state of kefiran to be more amorphous. In addition, the esterification modification led to a decrease in the degradation temperature and an increase in the apparent viscosity based on the obtained data from thermal analysis and viscosity measurement. The results of the foaming and emulsifying properties confirmed the improvement in surface properties of the modified kefiran. The frequency sweep test illustrated that with an increase in DS, the viscoelastic behavior of the kefiran cryogels to be more viscous. It can finally be stated that the modification with OSA was a high potential strategy to extend the industrial applications of the kefiran.

Pullulan (PU) is an exo-polysaccharide used in the food and pharmaceutical industries. However, the use of PU in different industries is limited due to its highly hydrophilic nature and consequently weakness in surface properties which can be remedied by its chemical modification with octenyl succinic anhydride (OSA). For this purpose, PU modification with OSA was optimized and the results showed that the maximum degree of substitution (0.061 ± 0.003) was obtained under pH of 9.0, pullulan concentration of 40% (w/w), temperature of ~40.90 °C, reaction time of ~101.21 min and OSA concentration of 14.96% (w/w). Also, the grafting of OSA on pullulan structure was confirmed by FTIR, 1H NMR and zeta-potential analyzes. Although this modification had no significant effect on the amorphousity of pullulan, it led to an increase in viscosity and a decrease in decomposition temperature and surface tension. Improvement of emulsifying properties of PU-OSA sample was proved by the evaluation of emulsifying capacity of un- and modified samples and also, zeta-potential, particle size and viscosity of the prepared emulsions. In line with surface characteristic results, an increase in foam capacity of modified samples was observed with decreasing the interfacial tension.

In this study, encapsulation of ursolic acid (UA) in electrosprayed gelatin nanoparticles and structural modification of the particles through adjusting solution properties was carried out. Atomization of a gelatin solution without UA resulted in smooth particles with mean diameter of 570.1 ± 299.3 nm; however, upon the addition of UA, the particles developed with irregular morphologies and the mean diameter increased to 752.3 ± 706.3 nm. Modification of the particle characteristics using sodium dodecyl sulfate and ammonium oxalate resulted in particles with improved morphology uniformity, mean diameter of 702.8 ± 182.8 nm and encapsulation efficiency of ∼87%. FTIR spectra pointed to stabilization of UA in nanoparticles through establishing hydrogen bonds with gelatin molecular chain. XRD patterns showed that upon encapsulation, UA crystalline nature was changed to a more amorphous state. DSC thermograms illustrated that the nanoparticles would be able to maintain stability at the temperatures up to ∼90 °C. Release studies suggested that the encapsulation extended the release period and decelerated the release rate of UA in PBS solution, and improved its bioaccessibility by 945.58% at the end of simulated gastrointestinal tract. The overall results demonstrate the successful enhancement of particle characteristics and also suggest that electrosprayed gelatin nanoparticles could be a suitable carrier for UA.

This study aimed to design mixed hydrogels composed of whey protein aggregates (WPA)/k-carrageenan with a tailored microstructure to protect curcumin within the upper gastrointestinal tract and deliver it to the colon. Curcumin was loaded in WPA and followed by cold gelation of the aggregates in the presence of k-carrageenan. The Microstructure of the hydrogels varied from homogenous to protein continuous or k-carrageenan continuous depending on the k-carrageenan concentration (0.0, 0.1 and 0.55%, w/w). The physical stability of curcumin toward precipitation during gelation of curcumin-loaded WPA was significantly improved after k-carrageenan addition. The higher capacity of k-carrageenan containing gels to curcumin entrapment was attributed to curcumin embedment inside of the rich-protein microdomains (called microgels), higher viscosity of the gel pre-solutions contained k-carrageenan and the shorter gelation time of the corresponding gels. Moreover, it was found about 31% of the loaded curcumin was released in the simulated gastrointestinal tract for pure WPA gels, while after addition of 0.55% k-carrageenan to WPA gels, more than 87% of loaded curcumin were delivered to the colon. Besides, 33% of curcumin degraded after the gastrointestinal digestion, while for WPA gels containing 0.1% and 0.55% k-carrageenan it was only 9.6% and 3.5%, respectively. The results were attributed to the protective effect of k-carrageenan to protein during in vitro digestion so that the access of digestive enzymes into the hydrogels was limited resulting in a reduction of gel matrix erosion and curcumin release. Therefore, curcumin remained bound to the protein and was not damaged during digestion until it reaches the colon.

In this study, to improve the water resistance properties of pullulan (PU) edible-films, the combination of the modification with octenyl succinic anhydride (OSA) and beeswax (BW) incorporation was used. The FTIR spectra results confirmed the PU octenylsuccination and also the presence of the BW in the composite films. The scanning electron microscopy (SEM) micrographs showed that the PU modification with OSA powerfully retarded the coalescence of BW droplets in film casting process and led to their homogeneity in the dried films. Also, the findings indicated that the water-proof properties including water solubility, water vapor permeability and water contact angle in the PU films were improved by the PU modification and BW incorporation. In addition, the obtained data showed that the octenylsuccination of PU had a negative effect on the mechanical properties of the produced films, while BW incorporation into PU-OSA films led to resolve this drawback.

In this study, the effects of fat (0.5 %, 3.2 % and 5.0 %), inulin (0.0 and 1.0 %) and starter culture (0.0 %, 0.5 %, 1.0 % and 1.5 %) on the angiotensin converting enzyme (ACE)-inhibitory activity of probiotic yogurt containing non-viable bacteria were assessed. Proteolytic activities of bacteria were also investigated. Yogurts were prepared either using a sole yogurt commercial culture including Streptococcus thermophilus and Lactobacillus delbrueckii subs. bulgaricus or bifidobacterium animalis BB-12 and Lactobacillus acidophilus La5 in addition to yogurt culture. Relative degrees of proteolysis were found to be considerably higher in yogurt samples than UHT milk as the control. Both regular and probiotic yogurts showed considerable ACE-inhibitory activities. Results showed that degree of proteolysis was not influenced by different fat contents, while was increased by high concentration of starter culture (1.5 % w/w) and reduced by inulin (1 % w/w). ACE-inhibitory activities of yogurt were also negatively affected by the presence of inulin and high levels of fat (5 % w/w). Moreover, yogurt containing probiotic bacteria showed higher inhibitory against ACE in comparison to the yogurt prepared with non-probiotic strains.

Summary Effects of different levels of fat and inulin on bacterial cell counts, degree of proteolysis and concentrations of organic acids in the yogurt containing inactivated cells of probiotic strains Bifidobacterium animalis and Lactobacillus acidophilus were investigated. Results showed that both L. acidophilus and B. animalis grew well in the yogurt samples reaching cell counts higher than 106 CFU mL−1 at the final pH of 4.5. Inulin at the concentration of 1% had no significant effects on the production of organic acids and cell counts of L. acidophilus, but promoted the growth of B. animalis with a reduction in the degree of proteolysis. Generally, different fat levels showed significant effects on the production of organic acids and nonsignificant effects on the cell counts of probiotic bacteria and degree of proteolysis. In case of lactic acid, the ratio of L- (+)to D- (−) isomer ranged from 50/50 to 80/20 in yogurt samples.

This study examined the feasibility of using kefiran, an exopolysaccharide obtained from kefir grains, as a new film-forming material. Kefiran-based films, with and without glycerol as plasticizer, were prepared by a casting and solvent-evaporation method. To study the impact of the incorporation of glycerol into the film matrix, physical, mechanical, and thermal properties of the films were investigated. As expected, the increase of glycerol concentration from 15% to 35% w/w increased extensibility but decreased tensile strength, implying higher mobility of polymer chains by the plasticizing effect of glycerol. Water vapour permeability of films was found to increase as the plasticizer content increased. Glass transition temperatures decreased as a result of plasticization as glycerol content increased. The properties of the films were related to their microstructure, which was observed by scanning electron microscopy. Thus, it was observed that plasticizer is a significant factor in the properties of these films and their food technology applications.

Two types of synbiotic ice cream containing 1% of resistant starch with free and encapsulated Lactobacillus casei (Lc-01) and Bifidobacterium lactis (Bb-12) were manufactured. The survival of L. casei and B. lactis were monitored during the product’s storage for 180 days at −20 °C. The viable cell number of L. casei and B. lactis in the free state in prepared ice cream mixture was 5.1 × 109 and 4.1 × 109 CFU/mL at day one and after 180 days storage at −20 °C, these numbers were decreased to 4.2 × 106 and 1.1 × 107 CFU/mL, respectively. When we encapsulated the mentioned probiotic bacteria in calcium alginate beads, the probiotic survival raised at rate of 30% during the same period of storage at same temperature. In general, the results indicated that encapsulation can significantly increase the survival rate of probiotic bacteria in ice cream over an extended shelf-life. The addition of encapsulated probiotics had no significant effect on the sensory properties of non-fermented ice cream in which we used the resistant starch as prebiotic compound.

New edible composite films based on kefiran and oleic acid (OA) at the ratio of 15, 25, and 35% (w/w) were prepared using emulsification with the aim of improving their water vapour barrier and mechanical properties. Film-forming solutions were characterized in terms of rheological properties and particle-size distribution. The impact of the incorporation of OA into the film matrix was studied by investigating the physical, mechanical, and thermal properties of the films. The water vapour permeability (WVP) of the emulsified films was reduced by approximately 33% by adding OA. The mechanical properties of kefiran films were also affected by adding OA: tensile strength was diminished, and elongation increased considerably. Differential scanning calorimetry showed that the glass transition temperature (Tg) of the kefiran film was −16 °C and was not considerably affected by adding OA. Therefore, OA could be incorporated into these films for some food-technology applications that need a low affinity toward water.