羧甲基纤维素钠对挤压豌豆蛋白素肉品质的影响

为了提高豌豆蛋白素肉的表观品质,探究挤压过程中多糖与蛋白相互作用对素肉品质的影响,本研究采用高水分挤压法,制作羧甲基纤维素钠（carboxymethylcellulose sodium,CMC）与豌豆蛋白粉混合基素肉,分析CMC添加量（0%、2%、4%、6%、8%）对豌豆蛋白素肉的质构特性、色泽、微观结构和蛋白分子作用力的影响,以及素肉蛋白二级结构、分子作用力与表观结构（质构、色差）的相关性。结果表明,维持豌豆蛋白素肉结构的主要作用力是二硫键。与未添加CMC相比,添加量4%CMC通过促进豌豆蛋白素肉中二硫键的形成,将素肉的硬度提高了95%。同时,观察到豌豆蛋白素肉具有光滑完整的表面和均匀的结构。二级结构中的无规卷曲含量增加,促进明亮度增强,CMC改善了豌豆蛋白素肉的品质。     

超声波法提取香蕉皮单宁及抗氧化活性研究

为了开发植物多酚类天然抗氧化剂,本试验以单宁产率为指标,利用响应面试验优化超声波法提取香蕉皮单宁工艺(超声功率、超声时间、料液比、乙醇浓度),并对其抗氧化性以及油脂保护率进行测定。结果表明,超声波法的最优萃取参数为超声功率430 W,超声时间40 min,料液比1:42 g/mL,乙醇浓度66%,此时单宁产率1.87%。随着单宁浓度增加,DPPH、超氧阴离子和羟基自由基清除率不断增加,单宁提取物对DPPH、超氧阴离子和羟基自由基清除率的半抑制浓度分别为0.300、1.185、0.730 mg/mL,其中DPPH和羟基自由基半抑制浓度低于V_C阳性对照组;随着单宁提取物添加量增加,大豆油加速氧化过程中过氧化值显著降低(P<0.05),在96 h油脂保护率较高;并且单宁添加量0.04%时,大豆油过氧化值最低,此时油脂保护率显著高于单宁添加量0.02%与0.06%(P<0.05)。因此单宁提取物能够起到抑制油脂氧化的作用。     

基于挤压蒸煮的荞麦粉加工品质改良及其机制研究

文章分析了挤压蒸煮对荞麦粉室温黏度和凝胶特性的影响,并利用体积排阻色谱测定了淀粉的分子量分布,探讨预糊化处理改善荞麦粉凝胶特性的机制;基于面带质地评价方法,优化预糊化荞麦粉在50%荞麦挂面中的添加比例。结果表明:荞麦粉经挤压蒸煮后,常温水中可形成凝胶;室温黏度显著增加;在主区温度200℃,水分含量18%,螺杆转速220r/min的条件下,所得预糊化荞麦粉中聚合度(DP)为6～50的支链淀粉分子最多,且此时凝胶强度最大。当预糊化荞麦粉添加量为10%时,面带抗拉能力最佳,黏附能力适中。由此可见,预糊化荞麦粉中特定链长的支链淀粉分子(DP 6～50)与凝胶品质呈正相关;50%荞麦挂面中添加适量预糊化粉可显著改善挂面的加工性能。     

豌豆蛋白的改性及其在食品中应用的研究进展

豌豆是人类饮食中高品质植物蛋白的重要来源,其蛋白质成分是低致敏性的,一些学者对豌豆蛋白功能性进行了部分研究,但依然缺乏改性方法对豌豆蛋白结构和特性影响的系统报道。为了扩展豌豆蛋白在食品工业领域的应用,本文介绍了物理改性、化学改性、酶法改性和复合改性方法对豌豆蛋白结构和功能性质的影响,同时介绍了豌豆蛋白在活性成分的封装、乳液、其他蛋白的替代以及食品的优化这些方面的研究进展,并对豌豆蛋白在食品工业的应用前景上进行了展望。     

Enhancement of safety and quality of ready-to-cook Asian green mussel using acidic electrolyzed water depuration in combination with sous vide cooking

Emerging technologies were combined to ensure the safety for consumers of Asian green mussel (AGM; Perna viridis). The combination of acidic electrolyzed water (AEW) depuration and sous vide cooking effectively reduced Vibrios while maintaining the quality of mussel. The use of AEW depuration combined with sous vide cooking at 100 °C for 1 min (D/SV-1) provided the yield of mussel meat of 27.22%, maintained the color, and texture properties. It could prevent the oxidation of polyunsaturated fatty acids and caused no changes in patterns of main proteins including paramyosin, actin and tropomyosin. Vibrio parahaemolyticus, V. vulnificus and Shewanella algae in AGM without treatment were 4.12, 3.00 and 3.30 log₁₀ CFU/g, respectively. Those bacterial species were confirmed by MALDI Biotyper® technique. They were potentially inactivated by the selected process. In addition, the next generation sequencing (NGS) based on the 16S rRNA gene revealed a low percentage of V. vulnificus genome (2.72%) and the complete elimination of other naturally existing Vibrios. Overall, AEW depuration of raw mussels, followed by sous vide cooking could be a promising method for the production of safe ready-to-cook Asian green mussels for consumption.Industry relevanceCommon Asian green mussel (AGM; Perna viridis) may represent a risk for public health associated with pathogenic bacteria originating from the aquatic environment. It also deteriorates rapidly within 1–2 days because of its perishable nature, thus losing its market value. To tackle such problems, appropriate pretreatment using acidic electrolyzed water depuration, followed by sous vide cooking under proper conditions could be implemented for safety assurance of ready-to-cook AGM by eliminating both pathogenic and spoilage bacteria. Also, the eating quality could be maintained. As a consequence, the technology developed in the present study could offer an effective solution for ensuring customer safety without compromising eating quality. It could be commercially employed for seafood processing industry, especially for bivalve mollusks, e.g., mussels, scallops, and clams.     

Photodynamic inactivation of spoilers Pseudomonas lundensis and Brochothrix thermosphacta by food-grade curcumin and its application on ground beef

This study evaluated the bactericidal effects of curcumin-mediated photodynamic inactivation (PDI) combined with citric acid on meat spoilage bacteria, and their preservative effects of refrigerated beef. After treatment of PDI (60 μM curcumin and 33.01 J/cm²) combined with 0.5 mg/mL citric acid, the populations of Pseudomonas lundensis and Brochothrix thermosphacta in PBS solution were reduced by 3.07 and 6.14 log CFU/mL, respectively, compared to 0.31 and 1.39 log CFU/mL for PDI. Combined treatment enhanced reactive oxygen species (ROS) activity in the two strains, and damaged their cell morphology, especially B. thermosphacta. With increasing curcumin concentration, the growth rate of spoilage bacteria was significantly inhibited (P < 0.05), and the changes of dominant spoilage species in bacterial community were retarded in aerobic-packaged and vacuum-packaged ground beef at 4 °C. Compared to the control, trichloroacetic acid-soluble peptide and total volatile basic nitrogen production were greatly restrained, and changes in pH values and brown color were apparently reduced for the combined treatment, which could extend the shelf life by 2 days. These results suggested the synergistic potency of PDI combined with citric acid against spoilage bacteria in meat products.Industrial relevance: The proliferation and spread of some psychrotrophs are major causes of quality deterioration and cross-contamination in fresh meat during cold chain. This study revealed that photosensitized curcumin combined with citric acid significantly decreased the survival of two psychrotrophic spoilage bacteria and extended the shelf-life of ground beef. Thus, curcumin-based PDI provides a new insight for the development of efficient and economic preservation in the meat processing industry.     

Functional Characteristics of Oleogel Prepared from Sunflower Oil with β-Sitosterol and Stearic Acid

β‐Sitosterol (Sit) and stearic acid (SA) were combined at varying ratios (w/w) and added to sunflower oil (SFO) at the concentration of 20 g/100 g oil for preparing edible fat‐like oleogel. The oleogel was characterized using an optical microscope, Fourier transform infrared spectroscopy (FTIR), X‐ray diffractometer (XRD), differential scanning calorimeter, and texture analyzer. The oil‐binding capacity, melting temperature, and firmness of the oleogel increased with the increase in the amount of SA in the gelator combination (Sit:SA, w/w). The microscopic analysis showed that the gel network formed based on the crystallization and self‐organization of gelator molecules, and both gelators showed an independent crystalline behavior in the oleogel. In addition, the FTIR spectra showed that the gel network formed via physical entanglements and was stabilized by non‐covalent interactions such as hydrogen bonding. Furthermore, XRD diffraction patterns indicated high lateral packing of molecular layers in oleogel prepared with the Sit and SA combination compared with oleogel prepared with a single gelator. On the other hand, for studying the effect of varying concentrations of gelator combinations, the Sit3:SA2 (w/w) combination was added to SFO at concentrations of 10, 15, 20, 25, and 30 g/100 g oil. Specific characteristics such as the oil‐binding capacity and firmness of the oleogel improved as the concentration of the gelator combination (Sit3:SA2) increased from 10 up to 30 g/100 g oil. Therefore, it can be concluded that the saturated fat alternative oleogel can be prepared from SFO with a specific Sit and SA combination ratio and concentration.     

蒸煮处理对马铃薯全粉细胞结构及消化特性的影响

本文以新鲜马铃薯为原料,研究了蒸煮时间对马铃薯全粉的细胞结构、游离淀粉含量、理化性质及消化特性等的影响.结果表明:随着蒸煮时间的延长,马铃薯蒸煮悬浊液电导率从24μm/cm提高到1285μm/cm,全粉碘蓝值(BVI)从8.31增大到19.00,这表明马铃薯全粉中细胞的破损率提高,破损程度增大,胞内物质的释放量及游离淀...     

不同模式超声预处理对莲子蛋白酶解物及其结构的影响

超声波参数中,超声频率是影响蛋白酶解的主要因素。因此,本实验以不同模式超声频率下得到的莲子蛋白酶解物为研究对象,首先对不同模式超声进行优化,以血管紧张素转化酶（angiotensin converting enzyme,ACE）抑制率和水解度为指标,得出了不同模式下的最优频率参数：单频率超声20 kHz、双频率组合20/35 kHz、三频率超声组合20/35/50 kHz。然后采用表面疏水性、氨基酸分析及内源性荧光光谱等表征不同模式的超声预处理对莲子蛋白酶解物及结构特征影响。结果显示：随着超声频率组合增多,表面疏水性越来越大,疏水性氨基酸含量增多,主要是由于超声预处理使蛋白结构展开,使最初被掩埋在蛋白分子内部的疏水基团暴露。通过荧光光谱发现,超声预处理提高了莲子蛋白的荧光强度,且荧光强度顺序为三频＞双频＞单频;同时,莲子蛋白酶解物λmax发生轻微的红移现象。上述结果对于莲子蛋白酶解及ACE抑制肽的制备至关重要。     

肉桂酸基油脂凝胶的制备及其流变特性和结晶特性分析

选择米糠油为溶剂体系,肉桂酸作为凝胶剂制备油脂凝胶,借助流变仪、X-射线衍射仪、荧光显微镜研究其流变特性及结晶特性。结果表明：米糠油凝胶的持油性和熔点随肉桂酸添加量的增加逐渐增加,当肉桂酸添加量超过10%,油脂凝胶的持油性和熔点增加不显著（P＞0.05）;米糠油凝胶的持油性随加热温度升高迅速上升,在85?℃时升高至93.62%,此时的凝胶熔点也相对较高;当冷却温度从0?℃升高至5?℃时,凝胶的持油性和熔点相对较高,当冷却温度进一步升高,凝胶的持油性和熔点显著下降至93%（P＜0.05）。通过对肉桂酸添加量10%、加热温度85?℃、冷却温度5?℃形成的油脂凝胶进行流变学特性分析,发现该油脂凝胶呈现假塑性流体状态,样品的表观黏度-剪切速率的关系符合幂律方程关系;并且在频率扫描范围内,油脂凝胶体系的储能模量（G’）明显大于损耗模量（G”）,样品形成较为紧密的凝胶结构;通过凝胶结晶特性分析发现,米糠油凝胶中的结晶结构细小,分布均匀,存在同质多晶现象,主要含有β和β′?2?种晶体类型。