大豆蛋白纳米纤维对铁纳米颗粒的稳态化作用

为明确大豆蛋白纳米纤维的结构形成和扩宽铁强化剂的食品工业应用，以大豆分离蛋白（soy protein isolate，SPI）为原料，通过5 h的酸热处理制备纳米纤维（soy protein isolate fibrils，Fib SPI），系统研究纤维形成前后蛋白结构的变化，并进一步制备铁纳米颗粒（iron nanoparticles，Fe NPs），探究Fib SPI对铁的稳态化作用。研究结果表明：在酸热处理过程中，SPI产生大量的β-折叠结构，其与硫磺素T结合，显示出增强的荧光强度；此外，7S组分先发生降解，利于纤维成核形成，随后11S逐渐被水解，促进纤维生长；同时水解产生大量的小肽组分，提高了产物的还原力。研究进一步利用Fib SPI递送铁纳米颗粒（Fe NPs），发现与原始SPI相比，铁纳米颗粒可在Fib SPI原位形成胶体稳定的铁-大豆蛋白纳米纤维复合物（Fe FibSPI），并以Fe（II）形式存在，其对乳液体系色泽及稳定性的影响较硫酸亚铁或氯化铁小。该研究可为构建新型植物基铁强化剂递送体系提供理论和方法指导。     

Improved aqueous solubility,bioaccessibility and cellular uptake of quercetin following pH-driven encapsulation in whey protein isolate

The purpose of this study was to increase the water solubility and potential bioavailability of quercetin by encapsulation in whey protein isolate (WPI) based on a green, efficient pH-driven method. According to the results, the water solubility of quercetin increased by 346.9: times after loading into WPI nanoparticles. When the initial quercetin concentration was 0.25 mg mL⁻¹ and WPI was 2% w/v, the encapsulation efficiency reached 94.1%, the Z-average diameter was 36.63 nm, and the zeta potential was −36.4 mV at pH 7.0. The fluorescence spectroscopy assay suggested the molecular complexation of quercetin and WPI at pH 12.0. X-ray diffraction assay indicated the enclosure of amorphous quercetin in WPI. Correspondingly, the bioaccessibility increased from 2.76% to 31.23% and the Caco-2 cell monolayer uptake increased from 0% to 2.12% after nanoencapsulation. This work confirmed that the pH-driven method is an effective approach to prepare WPI–quercetin nanocapsules to improve physical and potentially biological properties of quercetin.     

Application of ultrasound treatment for modulating the structural,functional and rheological properties of black bean protein isolates

The modulating effect of ultrasound treatments at varying powers and times on the structural and functional properties of black bean protein isolate (BBPI) was investigated. Compared with native BBPI, low-power (150 W) and medium-power (300 W) ultrasound treatments increased the solubility, foaming and emulsifying properties of BBPI, especially at 300 W, 24 min. This effect arises predominantly due to increased exposure of hydrophobic groups, which serve to increase the interactions between the protein and water molecules. Additionally, an increase in the protein surface activity improved the absorption of protein molecules at the oil–water and air–water interfaces. Rheology data showed that increased hydrophobic and hydrogen-bonding interactions improved the water-holding capacity of BBPI gels following ultrasound treatment. However, high-power (450 W) ultrasound treatment weakened the functional properties of BBPI, and this was likely due to the formation of macromolecular BBPI aggregates. Overall, this study indicates that ultrasound treatment could be a promising approach for modulating other plant protein resources as well as expanding the application of black bean protein.     

Preparation and characterisation of soya milk enriched with isoflavone aglycone fermented by lactic acid bacteria combined with hydrothermal cooking pretreatment

A fermented soya milk (FSM) enriched with isoflavone aglycone (FSM‐SPIA) was prepared from heated soya protein isolate (SPI)‐isoflavone complex. After 48 h of fermentation, FSM‐SPIA contained higher contents of living bacteria, free amino acids and aglycone compared with the FSM of SPI (FSM‐SPI) and the FSM of SPI‐isoflavone complex (FSM‐Mix). In the in‐vitro digestion experiment, FSM‐SPIA showed higher antioxidant capacity and isoflavones (ISO) bioavailability than FSM‐SPI and FSM‐Mix. This was likely due to the soya milk containing a higher level of amino acid, peptides and the presence of soya bean isoflavone. The improved protein digestibility, the interaction and binding ability between proteins and ISO may affect the properties of the protein and the fermented products. The FSM enriched with isoflavone aglycone can be used as a functional fermented drink, as well as an auxiliary food for menopausal women during a specific pathological period.     

Preparation and characterisation of films from xylose‐glycosylated peanut protein isolate powder

This work aimed at producing and characterising xylose‐glycosylated peanut protein isolate (PPI‐X) films by dissolving PPI‐X powder in water at ambient temperature and further plasticising with glycerol. The effect of powder dissolution temperature (20–100 °C) and glycerol concentration (15.0–45.0%, w/w) on mechanical properties and integrity of these films was quantified. The results showed that the powder dissolution temperature had no significant effect on the mechanical and water resistance properties of PPI‐X films within the temperature range tested. With increasing concentration of glycerol, the tensile strength and water resistance of PPI‐X films decreased and elongation increased. The films produced by dissolving the PPI‐X powder at 20 °C and plasticising with 25.0% glycerol had comparable mechanical properties and better water resistance compared to some other plant protein films plasticising with glycerol. The results suggested that PPI‐X films could potentially be used as biodegradable packaging materials.     

Evaluation of red bean protein [Vigna angularis] isolate on rheological properties of pork myofibrillar protein gels induced by microbial transglutaminase

The effects of 1% red bean protein isolate (RBPI) on the gel properties of myofibrillar protein (MP) in various levels of microbial transglutaminase (MTG: 0%, 0.1%, 0.5%, & 1%) were evaluated. The cooking yield (CY) of the MP gels decreased with increasing MTG level, while the addition of RBPI improved the CY of the MP gels. Gel strength (GS) was also improved when RBPI was incorporated into the MP gels containing higher than 0.5% of MTG. The addition of MTG and RBPI was slightly changed the endothermic peak temperatures. Scanning electron microscopy (SEM) showed that the three‐dimensional structure of MP with RBPI alone or in combined with MTG was compacted as compared to the control. Based on the results, RBPI could be functioned as a substrate for MTG (0.5–1.0%) and a water binder of meat protein gel mediated by MTG.     

橄榄油与椰子油混油基对类蛋黄酱乳液流变及冻融稳定性的影响

以类蛋黄酱体系为研究对象，运用Turbiscan、流变仪、粒度仪、显微镜研究在pH 3条件下橄榄油与椰子油不同比例复配（10∶ 0、9∶ 1、8∶ 2、7∶ 3）的混油基对于乳清分离蛋白-蛋黄卵磷脂稳定的乳液体系流变性质及冻融稳定性的影响。结果表明：随着椰子油比例增加，乳液黏度增加，弹性模量增加，橄榄油与椰子油质量比7∶ 3复配混油基制得的乳液具有最大的黏度和最高的弹性模量；所有乳液在4~40 ℃弹性模量下降，说明乳液在贮存、冷藏运输过程中内部结构完整，乳液具有良好的稳定性;蛋黄卵磷脂能够提高含椰子油（饱和脂肪酸含量高）乳液的冻融稳定性，并且椰子油比例越大（饱和程度越高），冻融稳定性提高效果越好;乳液冻融稳定性从高到低依次为橄榄油与椰子油质量比为7∶ 3>8∶ 2>9∶ 1>10∶ 0。     

Combined effect of antimicrobial edible coatings with reduction of initial microbial load on the shelf-life of fresh hake (Merluccius merluccius) medallions

Two distinct strategies were combined to preserve fresh fish (Merluccius merluccius) under refrigeration at 4 °C for 12 days: (i) the application of an antimicrobial edible coating enriched with oregano essential oil (OEO) or carvacrol (CV) and (ii) the reduction of initial microbial load by good handling practise and the use of sodium hypochlorite (NaOCl). The action of antimicrobial coatings alone retarded the growth of Enterobacteriaceae, lactic acid bacteria (LAB) and H₂S producing bacteria on fish samples. The reduction of initial microbial load by itself only affected the evolution of LAB, but not the rest of the bacterial groups. When using both techniques combined, edible antimicrobial coatings were significantly more effective with additional and significant delays in the growth of mesophilic, psychrotrophic and Pseudomonas bacteria. Thus, the use of both strategies combined resulted in a reduction of the counts of all bacterial groups after 12 days of storage which ranged from 1.5 log and 8 log, in Pseudomonas and H₂S producing bacteria, respectively. Moreover, no significant differences were observed when comparing the microbiological evolution of samples treated with OEO compared to those only treated with CV.