内源性蛋白酶对花生蛋白纤维化凝胶的影响

花生含有内源性蛋白酶可以水解花生蛋白，主要探究该水解作用对花生蛋白纤维化凝胶形成的影响。研究发现花生内源性蛋白酶可在pH 2~5下水解花生蛋白，尤其是Ara h 1。在pH 3时，内源性蛋白酶对花生蛋白的水解作用最强，可生成相对分子质量分别为25、19、17、13 kDa和12 kDa的多肽产物；且在pH 3时可形成透明凝胶，而其他pH均不可。以100 g/L的蛋白溶液体系（反应条件为pH 3、60 ℃）为对象，通过蛋白酶抑制剂对比实验，确定起主导水解作用的是天冬氨酸蛋白酶，该酶导致的花生蛋白水解对于透明凝胶形成起主导作用。透射电子显微镜结果显示，上述透明凝胶的确为纤维状蛋白所形成，此蛋白纤维的直径小于10 nm，长度超过1 μm。同时通过考察蛋白质量浓度对透明凝胶形成的影响发现，100 g/L的蛋白溶液可在6 h内形成透明凝胶，50 g/L的蛋白溶液可在12 h形成，而25 g/L的蛋白溶液在24 h也不能形成。研究为纤维状食源蛋白的制备提供了新思路，并且制备条件较为温和，有利于实际运用。     

Characterisation of peanut protein concentrates from industrial aqueous extraction processing prepared by spray and freeze drying methods

Peanut protein concentrates (PPCs) were prepared by aqueous extraction processing (AEP), organic solvent extraction processing (SEP) and prepress-organic solvent extraction processing (P-SEP) and converted into powder by freeze and spray drying. The drying method showed an influence on the surface morphology and second structure of PPCs. Peanut protein concentrates of AEP were found to have lower protein contents, solubility and higher surface hydrophobicity, resulted in similar emulsion ability index (EAI) values and lower emulsion stability index (ESI) and water-holding capacity (WHC) values compared to PPCs of SEP and P-SEP. Foaming capacity was barely affected by oil extraction processing and drying methods, foaming stability was significantly influenced by oil extraction processing. Freeze-dried PPCs had higher solubility, WHC and fat absorption capacity than spray-dried PPCs, which was not the case for EAI and ESI. Hence, PPCs of AEP showed adequate functional properties, making AEP more appropriate for phytoprotein beverages.     

Physical,chemical and oxidative changes in raw peanuts: Effect of relative humidity

Peanuts are susceptible to oxidative deterioration due to various factors during storage. This research studied the proximate composition (lipid, protein, total sugar, moisture and ash.), composition and content of amino acids and fatty acids, peroxide value (PV), carbonyl value (CV), malondialdehyde content (MDA), protein composition and structure changes in the peanuts stored for 320 days under different relative humidity (RH; 50%, 65% and 80%) conditions. Lipid oxidation was delayed at low RH (50% and 65%) storage conditions. At high RH (80%), the contents of unsaturated fatty acids, amino acids, protein and lipids decreased significantly during storage (P < 0.05), whereas the PV, CV and MDA contents increased significantly (P < 0.05). The CV values of YH-9326 and YH-22 increased by 14.46 and 17.48 times respectively. In addition, the protein structure changed throughout the whole storage period (P < 0.05). This research provides a theoretical reference for maintaining storage quality and extending shelf life.     

食物过敏：从致敏机理到控制策略

全球范围内食物过敏的发生率逐年升高，食物过敏现已成为人们日益关注的食品安全和公共卫生问题。本文系统综述了近年来食物过敏领域的研究进展，包括食物过敏的流行病学特征、分子机制与机体发生的风险因素，食物致敏原的识别、评价与检测技术，以及食物过敏的诊断、控制及标识的风险评估等；在此基础上，深入探讨了食物过敏与致敏原相关研究的瓶颈挑战与策略，以期为食物过敏的预防和控制，低/无敏食品的研发，以及保障食物致敏原安全提供参考和借鉴。     

花生油高频剪切黏度超声检测

为对多次高温加热食用油品质进行评价,以反复煎炸花生油为研究对象,基于超声水平剪切波(SH波)在固体/黏弹性液体界面的复反射系数与液体黏弹性模量、黏度系数等关系模型,以固体/空气界面为参考,采用固/气、固/液界面回波对比方法,测量了不同劣化状态花生油在室温时的剪切黏度,并与流变仪测试结果进行比较。结果表明,超声SH波与流变仪均很好地反映了样品黏度随加热次数的变化关系。研究证明超声方法在线评价油品劣化状态具有可行性。