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• Hydroxypropyl methylcellulose (HPMC) was blended with hydroxypropyl starch (HPS) • The continuous phase of HPMC-HPS mixed hydrocolloid changed with HPMC/HPS ratio. • Hydroxypropylation promoted HPMC gelation. • Good compatibility between HPMC and HPS enhanced the HPMC-HPS gel strength. • HPMC hydroxypropylation improved the oxygen barrier effect of HPMC-HPS film. This work investigates the structure, processability, and film performance of hydroxypropyl methylcellulose (HPMC) hydrocolloids affected by hydroxypropy substitution degree and blending with hydroxypropyl starch (HPS). The hydroxypropylation of HPMC could increase inter-chain hydrogen bonding, thereby promoting its gelation, and improve film-forming, but reduce the mechanical properties of the films. HPMC-HPS mixed hydrocolloid system showed a typical "sea-island" morphology with the continuous phase changing with blend ratio. The content of hydroxypropy groups of HPMC affected the compatibility between HPMC and HPS, the morphology of the discrete phase, and the rheological properties of the blends. The fluid-like HPS enhanced the gel strength of HPMC when they had better compatibility. With a higher degree of hydroxypropy substitution, blend films exhibited a much denser structure, better oxygen barrier property, and appropriate mechanical properties. The knowledge obtained from this work could guide the development of edible packaging materials with desired properties and functionality. [ABSTRACT FROM AUTHOR]

• Combing usage of QuEChERS and DLLME for the determination of neonicotinoid residues in grains. • Smart role of water as extractant in QuEChERS and as external phase in DLLME. • Extraction relay using MeCN after water in QuEChERS and successive play of MeCN as dispersant in DLLME. • Comprehensive consideration of the single factor test and response surface method to optimize parameters. • Good sensitivity, precision, and applicability of the developed method for real grains samples. Monitoring neonicotinoid residues in grains is of significant interest for the proper assessment of pesticide exposure to human. The quick, easy, cheap, effective, rugged, and safe extraction method combined with dispersive liquid-liquid micro-extraction (QuEChERS-DLLME) was developed for extracting, purifying, and concentrating seven common neonicotinoid pesticides from the grains (rice, millet, and maize). Water and acetonitrile were used in tandem as extractants in QuEChERS, while water, acetonitrile, and trichloromethane in DLLME acted as the external phase, dispersant, and extractant, respectively. Comprehensive consideration of the single factor test and response surface method to optimize parameters including type and volume of extractants and dispersant. The evaluation showed that the QuEChERS-DLLME method held excellent linearity (R2 > 0.99). The limits of quantitation ranged from 0.003 to 0.08 µg kg−1 for the seven insecticides. The recoveries were in the range of 62–118%, and good reproducibility was obtained with a relative standard deviation below 15%. [ABSTRACT FROM AUTHOR]

• A novel cold-set rice starch (RS)/heat-set curdlan composite gel systems prepared. • The RS-curdlan interaction affects the composite gel's structure and properties. • The 5:5 composite gel starts to show rheological properties dominated by curdlan. • Curdlan inclusion in RS enhances gel structure density and mechanical properties. • A schematic proposed for temperature-induced conformational change. In pursuit of advancing the understanding of composite gel systems, this study delves into the intricate realm of rheology, structural elucidation, and mechanical attributes. Specifically, it scrutinizes the symbiotic interplay between rice starch, a cooling-set gel, and curdlan, a thermo-irreversible heating-set gel. A higher curdlan content enhances the inter-chain hydrogen bonding between rice starch and curdlan, resulting in a denser gel structure and thus increased moduli, solid-like behavior, and mechanical properties, and reduced frequency-dependence, especially at high temperatures (>65 °C). For example, with 50 % curdlan incorporation, G ′ (90 °C) improved by 252 %. Notably, thermal treatment can compromise the structural integrity of the rice starch gel, reducing strength and softening texture. However, this textural degradation can be effectively mitigated with, for example, 30 % curdlan incorporation, resulting in a 55-fold hardness increase at 85 °C. The knowledge gained from this work offers valuable guidance for tailoring starch-based gel products to specific properties. [ABSTRACT FROM AUTHOR]

• Retrogradation of short linear glucan debranched from amylopectin was investigated. • The retrogradation process of debranched starch (DBS) takes only 0–120 min. • The retrogradation of DBS is an ultra-short-term process. • The retrogradation enthalpy increased with increase in degree of polymerization. • The retrogradation enthalpy of DBS increased as storage time increased. Retrogradation is inevitable during the storage of starchy products. Retrogradation behavior of starches (e.g., amylopectin and amylose) has been widely investigated. We firstly studied the retrogradation behavior of short linear glucan debranched from amylopectin with different degrees of polymerization (DP). With increasing DP, the retrogradation enthalpy change (ΔH) of debranched starch (DBS) increased. At a DBS to water ratio of 1:2 and a storage time of 0 min, the retrogradation ΔH of DBS samples (DP 11.96, 12.62, and 13.36) reached up to 6.03 ± 0.41, 8.03 ± 0.53, and 12.80 ± 1.57 J/g, respectively. The greater the short-chain length, the more rapid the retrogradation of DBS. The peak temperature of retrograded DBS (101.95–111.53 °C) with a DBS to water ratio of 1:2 stored at 50 °C was greater than that stored at 4 °C. The retrogradation of DBS was rapid, taking only 0–120 min, corresponding to ultra-short-term retrogradation. [ABSTRACT FROM AUTHOR]

Highlights • Starch nanoparticles (SNPs) were modified by annealing (ANN). • The relative crystallinity of SNPs significantly increased after annealing treatments. • The ANN-SNPs showed higher gelatinization temperature and lower melting range. Abstract Annealing offers a facile and green approach to the modification of starch. This study was the first to investigate the effect of annealing on the properties of waxy rice starch nanoparticles (SNPs). The spherical morphology of SNPs hardly changed after annealing, and the nanoscale size of the SNPs was maintained in the range of 50–120 nm. The relative crystallinity of modified SNPs increased from 53.71% to 63.46% after annealing at 55 °C for 48 h. The annealing treatment increased the melting temperature from 78.3 °C to 95.7 °C, but decreased the melting range from 30.8 °C to 25.3 °C. The increased 1047 cm−1:1022 cm−1 ratio suggested that annealing resulted in an efficient packing of double helices. This work suggests that annealing, a safe and green method, produces modifications which can improve the properties of SNPs and therefore expand their applications in the fields of food, nutraceuticals, and other materials. [ABSTRACT FROM AUTHOR]

Highlights • A new method to protect probiotics by chitosan and sodium phytate was developed. • The layer-by-layer technology was first used in Lactobacilli pentosus (LP). • The number of two-layered LP was 6.23 log cfu/mL after 3 h in bile salts. • The viability of LP improved after encapsulated during long time storage. Abstract Lactobacillus pentosus (LP) are widely used as probiotics in food products, dietary supplements, and nutraceuticals due to their health-promoting effects. To confer a functional effect, the probiotics need to survive during shelf-life and transit through the high acidic conditions of the stomach and bile salts in the small intestine. Herein, LP was firstly encapsulated in a layer-by-layer approach using chitosan (CS) and sodium phytate (SP). After digestion in simulated gastrointestinal fluid (SGF) for 120 min and 4% bile salts for 3 h, plain-LP exhibited a 7.40 and 6.09 colony forming units/ml (cfu/ml) reduction. Interestingly, two layer coated LP ((CS/SP) 2 -LP) exhibited less death, which reduced 4.34 and 2.33 log cfu/ml, respectively. Specially, (CS/SP) 2 -LP also showed a higher survival rate compared to plain-LP in heat treatment experiments, especially 65 °C. In conclusion, layer-by-layer encapsulation of LP has great potential for the protection and delivery of probiotics in food and nutraceutical products. [ABSTRACT FROM AUTHOR]

[Display omitted] • Chitin nanowhiskers formed a protein corona in simulated gastric fluid. • The corona decreased the charge of chitin nanowhiskers from 22.4 to 12.9 mV. • The interaction forces were mainly hydrogen bonds and van der Waals forces. • The slight changes in pepsin structure did not affect its activity. Protein corona (PC) usually changes the physicochemical properties of nanoparticles (NPs) and determines their ultimate fate in the physiological environment. As NPs are widely used in food, it is important to obtain a deep understanding of PC formation in the gastrointestinal fluid. Herein, we explored the adsorption of pepsin to chitin nanowhiskers (CNWs) and their interactions in simulated gastric fluid. Results suggest that the binding of pepsin reduced the surface potential of CNWs from 22.4 ± 0.15 to 12.9 ± 0.51 mV and caused their aggregation. CNWs quenched the fluorescence of pepsin and induced slightly changes in its secondary structure containing a reduction in the β-sheet content (∼ 3%) and an increase in the random coils (∼ 2%). The isothermal titration calorimetry (ITC) data suggested that the interaction forces between CNWs and pepsin were mainly hydrogen bonds and van der Waals forces. [ABSTRACT FROM AUTHOR]

• Hollow starch nanoparticles were obtained in an oil-in-water nanoemulsion system. • Nanoparticles were prepared by heterogeneous crystallization of debranched starch. • Nanoparticles with 0.5% debranched starch had uniform shells and globular shapes. • Thickness of their shells can be regulated by debranched starch concentration. The development of hollow nanoparticles has attracted widespread interest due to their potential commercial applications. This work aimed to prepare a novel hollow starch nanoparticles (HSNPs) from debranched waxy corn starch (DBS) via an oil-in-water (O/W) emulsion templating method. The effects of different concentrations of DBS on the formation of HSNPs at 4 °C and 25 °C were investigated. The monodispersed HSNPs obtained with 0.5% concentrations of DBS at 25 °C had spherical shapes, ranging between 200 and 800 nm. HSNPs with relative crystallinities of 16.9%–29.7% exhibited V-type or B + V-type structures, which indicated that DBS at low concentrations (0.5%–2.0%) could recrystallize and concomitantly form starch–lipid complexes around emulsion droplets. This novel approach of preparing HSNPs is viable and simple. The developed HSNPs could have great potential for delivering drugs or active ingredients. [ABSTRACT FROM AUTHOR]