酱油渣蛋白水解产物抗氧化性研究

比较六种不同的蛋白酶对酱油渣中蛋白的水解效果,筛选出最适合生产抗氧化肽的Alcalase+中性蛋白酶反应体系,在加酶量6000 U/g、pH=8、60℃、水解2h得到产物具有最好的抗氧化活性.从羟基自由基(OH·)清除能力、超氧阴离子自由基(O2-)清除能力、DPPH清除能力研究水解产物的抗氧化活性.10 mg/mL水...     

大豆蛋白酶水解产物的水解度对小麦粉及面条品质的影响

探讨了不同水解度的大豆蛋白酶水解产物对小麦粉及面条品质的影响,结果表明,添加不同水解度的酶水解产物后,小麦粉糊化特性的峰值黏度、最终黏度和最低黏度均比原小麦粉明显降低;除水解度为4.19%的水解产物外,添加其他水解度的酶水解产物的面团稳定时间均有所降低,弱化度增大;与原面粉面条相比,添加大豆蛋白酶水解产物后,面条的粘附性明显降低;添加不同酶水解产物的面条质构特性无显著性差异,添加水解度4.19%和7.45%酶水解产物的面条的拉伸特性与原小麦粉面条无显著性差异;当水解度超过5.34%后,面条的干物质损失率和蛋白质损失率明显增大。综合评价小麦粉和面条的品质指标,作为面条用粉时,添加的大豆蛋白酶水解产物的水解度4.19%为宜。     

Soy Protein Isolate Solubility and Surface Hydrophobicity as affected by Antioxidants

Addition of tert-butylhydroquinone or a mixture of butylated hydroxyanisole and tert-butylhydroquinone (200 ppm on a lipid basis) during SPI processing gave increased protein solibility over that of the control (55%. 56% and 34%. respectively). These increased solubilities correspond to 32% and 18% decrease in oxidation of free sulfhydryls and 20% and 12% reduction in protein oxidation, as determined by protein carbonyl content. Increased protein solubilities, due to added antioxidants, were accompanied by higher total protein surface hydrophobicity, as determined by the sodium dodecyl sulfate (SDS) binding method, and soluble protein hydrophobicity, as determined by the fluorescence probe 8-anilino-1-naphthalene sulfonate (ANS).     

酚型抗氧化剂的危险性分析

对具有抗氧化作用的合成和天然酚型抗氧化剂进行安全性和危险性评价试验，结果显示几茶素、黄酮醇等天然抗氧化剂比BHA、BHT有更高的抗氧化性；与间接致突变物(Trp-P-1)混合作用后，经代谢活化的有抑制突变的效果，非代谢活化的没有诱发突变；与直接致突变(1-NP)混合后非代谢活化时有抑制突变的效果，但是经过代谢活化后有诱发突变的趋势。     

Spray-Dried Soy Protein Isolate Solubility, Gelling Characteristics, and Extractable Protein as Affected by Antioxidants

With the addition of antioxidants, spray-dried soy protein isolates (SPI) exhibited increased solubilities by 8% over the control in 0.1M NaCl. Increased solubilities corresponded to a 15% and 8% reduction in protein oxidation as determined by protein carbonyl contents. The greatest differences in solubility between a spray-dried SPI with antioxidant (66% protein solubility) and the control (54% protein solubility), as well as the minimum protein solubility, occurred in 0.2M NaCl. Following the initial solubilization step in SPI processing, amount of extracted proteins was increased by 4.5% over the control with addition of antioxidants. Gel fracturability, hardness and adhesiveness for heat set gels of 12% SPI processed with added antioxidants were increased by 26.3%, 23.5% and 24.6%, respectively.     

燕麦酚类抗氧化成分研究进展

燕麦中含有众多酚类抗氧化成分,该文概述这类抗氧化物质组成及功能作用,并介绍不同提取 条件及加工工艺对燕麦抗氧化酚类物质影响。     

花生蛋白酶解液特性的研究

本文研究了碱性蛋白酶、中性蛋白酶与木瓜蛋白酶对花生蛋白的酶解效果。结果表明,在0～6h时,随着酶解时间的延长,酶解产物的氮溶解指数不断增大,酶解6h时碱性蛋白酶、中性蛋白酶与木瓜蛋白酶酶解产物的氮溶解指数分别为33.84%,29.40%和26.06%,其中碱性蛋白酶酶解产物的氮溶解指数最高。SDS-PAGE图谱显示,与碱性蛋白酶与中性蛋白酶酶解液相比,木瓜蛋白酶酶解液中相对分子质量为20,000～31,000之间的条带缺失,三种酶解液中的未被酶解的蛋白质其相对分子质量都集中在14,000～43,000之间,开发利用时应予以注意。     

Storage Stability of Vacuum Packaged Frozen Pork Sausage Containing Soy Protein Concentrate, Carrageenan or Antioxidants

Fresh pork sausage patties containing carrageenan, without or with soy protein and an antioxidant were packaged with or without vacuum. They were evaluated for sensory properties, visual color, thiobarbituric acid reactive substances (TBARS), and Hunter color ‘L’, ‘a’, ‘b’ values at 4-wk intervals during 16 wk frozen storage. Rosemary extract was as effective as butylated hydroxytoluene (BHT)/propyl gallate (PG)/citric acid (CA) in antioxidant properties, but patties with BHT/PG/CA showed less surface discoloration (P < 0.05). In fat-control (FC) products, antioxidants combined with vacuum packaging provided optimum protection against rancidity. With vacuum packaging (VP), reduced-fat products maintained acceptable quality (TBARS and sensory properties) during 16 wks frozen storage.     

葡萄酒中酚类物质抗氧化活性及构效关系

<正>酚类物质是芳香环上连有一个或多个羟基的低分子量有机化合物,其不但决定了葡萄酒的口感、色泽、贮藏寿命及稳定性,而且具有很强的抗氧化活性。葡萄酒中酚类物质对机体的防御作用归功于它特有的化学结构——酚羟基结构,它们具有供电子作用,通过提供活泼的氢捕捉机体内活性氧等自由基,阳断了自由基对机体的损伤。另外,葡萄酒中酚类物质也具有络合过渡金属离子能力、激活抗氧化酶的活性、减少α-生育酚自由基及降低氧化酶活性的能力。然而,尽管现在不同实验模式已证实了酚类化合物的这种多功效作用,但对于它们的构效关系的描述还不尽一致,因此,本文总结了酚类化合物(以类黄酮酚为例,见图1)在自由基清除作用和金属离子络合作用中关键的化学结构特征及影响,以旨为葡萄酒中酚类物质构效关系研究提供理论参考。     

大豆蛋白引领健康生活新概念

<正> 时下,替餐饮料、果汁、蔬菜培根、蔬菜热狗、运动营养棒已经开始引领健康饮食的发展方向,而健康的大豆蛋白食品更是受到了越来越多的关注。日前,大豆蛋白研究与食品应用领先企业Solae公司在上海展示了美味时尚的大     

大豆蛋白酶解物抗油脂氧化性研究

以过氧化值(POV)为指标,研究了大豆蛋白酶解物在大豆油中的抗氧化性能以及维生素C和柠檬酸对其抗氧化性的增效作用。结果表明,大豆蛋白酶解产物具有一定的抗氧化活性,且随添加量的增加而增强;维生素C和柠檬酸对大豆蛋白酶解物的抗氧化活性有显著的增效作用,但维生素C只在短时间内起作用。     

大豆蛋白速凝特性研究—Ⅱ不同凝固剂对速凝特性的影响

采用流变仪测定了添加不同量的葡萄糖酸内酯和木瓜蛋白酶对大豆蛋白速凝特性的影响，测定是在模拟热水冲调后体系温度变化的程序升温和降温条件下进行的。结果表明，在实验范围内，样品的特征弹性模量（Gs′）随内酯添加量的增多而增大；对木瓜蛋白酶而言，样品的Gs′随添加量呈现先增大后减小的趋势，转折点为0.133%；采用内酯和酶混合凝固剂可使样品的Gs′显著提高。此外，从测定得到的样品动态流变曲线可以看出，添加内酯时样品出现胶凝需要约200秒，而添加木瓜蛋白酶时样品出现胶凝所需的时间都在100秒以内，且随酶加量的增多而缩短。     

大豆蛋白的玻璃化转变

在有关玻璃态和玻璃化转变理论的基础上,综述了大豆蛋白玻璃化转变的分析方法、转谷氨酰胺酶处理的大豆蛋白低水分的玻璃化转变及大豆蛋白分子结构与其玻璃化转变关系,并对今后的研究方向作了展望。     

功能性大豆蛋白及其应用

介绍了大豆蛋白的主要功能特性、改性方法及应用。利用大豆蛋白的各种功能特性。可提高食品的风味、品质,改善传统食品的加工性能。降低成本,而功能性大豆蛋白在模拟食品,食品保鲜等方面的应用,更扩展了大豆蛋白的应用领域,大豆蛋白的功能特性的研究和大豆蛋白食品的开发,对调整膳食结构、发展新食品具有重要意义。     

毛霉蛋白酶水解大豆蛋白的工艺优化

选用毛霉菌株,对大豆蛋白原料进行水解,同时测定了不同水解条件下酶解液的水解度、蛋白回收率和肽氮含量,分析在不同条件下蛋白类呈味物质的变化情况。在单因素试验的基础上,运用Box-Behnken响应面分析法以水解度作为响应值,料液比、酶解温度和酶解时间为影响因子,对毛霉蛋白酶水解工艺条件进行优化,结果表明：最佳工艺条件为酶解温度34.3 ℃,酶解时间92.5 h,料液比1:2.2,不调pH。此条件下,验证试验得到水解度为5.62%,与模型预测值5.637%相比,结果相差较小,校正后的相关系数R2=0.9919,表明响应面模型与实际试验的拟合程度良好,可解释99.19%的响应值变化。三个影响因子对大豆蛋白水解度影响大小的排序为酶解温度>液料比>酶解时间。为利用毛霉天然发酵所产酶系去酶解大豆蛋白提供了一定的理论支持与数据参考。     

The Study of Phenolic Compounds as Natural Antioxidants in Wine

Plant phenolics present in fruit and vegetables, and that are particularly rich in red wine, have received considerable attention because of their potential antioxidant activity. Human consumption of antioxidants has many alleged health benefits, including protection against cardiovascular diseases, and, most recently, cancer. Red wines contain a variety of polyphenolic antioxidants. Five samples of commercial red wines from Spain and four phenolic compounds of red wine: gallic acid, trans-resveratrol, quercetin and rutin, have been studied. The total phenolics content and the total antioxidant activity (TAA) of wines was determined. The total phenolic content, determined according to the Folin-Ciocalteu method, varied from 1800 to 2300?mg/L, expressed as gallic acid equivalents (GAE). The antioxidative effects of wine phenolics were determined using a system based on the inhibition by antioxidants of the absorbance of the radical cation. The relationship between antioxidant activity of phenolic compounds, as hydrogen donating free radical scavengers, and their chemical structures was studied. Furthermore, the total antioxidant activity of the wines investigated was well correlated with phenol content. Thus, the results confirm that red wine polyphenols are, in vitro, significant antioxidants.     

油炸小食品中酚类抗氧剂的高效液相色谱法测定

采用反相高效液相色谱法测定油炸小食品中BHA、4HR、BHT、2,2-2甲基双(4-甲基6-叔丁基苯酚) (2246)的含量。采用V(甲醇):V(二氯甲烷)=9:1作提取剂,ODS-2HYPERSIL(250mm×4.6mm,5μm)色谱柱,体积分数80%的甲醇作流动相进行分离。结果表明:浓度在2.0～40μg/mL,4种物质均呈线性关系,相关系数为0.998 3～0.999 1,标准偏差为1.14%～5.90%,平均回收率均在80%以上,检出限2μg/g。因此,该方法可用于油炸食品中酚类抗氧剂的测定。     

Isolation and Identification of Phenolic Antioxidants in Black Rice Bran

Black rice bran contains phenolic compounds of a high antioxidant activity. In this study, the 40% acetone extract of black rice bran was sequentially fractionated to obtain 5 fractions. Out of the 5 fractions, ethyl acetate fraction was subfractionated using the Sephadex LH‐20 chromatography. The antioxidant activity of phenolic compounds in the extracts was investigated by 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical assay, 2,2‐azino‐bis‐(3‐ethylenebenzothiozoline‐6‐sulfonic acid) (ABTS) radical cation assay, reducing power. The subfraction 2 from ethyl acetate fraction had the highest total phenolic contents (TPC) (816.0 μg/mg) and the lowest EC₅₀ values (47.8 μg/mL for DPPH radical assay, 112.8 μg/mL for ABTS radical cation assay, and 49.2 μg/mL for reducing power). These results were 3.1, 1.3, and 2.6 times lower than those of butylated hydroxytoluene (BHT), respectively. At a concentration of 100 μg/mL, the antioxidant activity and TPC of various extracts was closely correlated, with correlation coefficients (R²) higher than 0.86. The major phenolic acid in subfraction 2 was identified as ferulic acid (178.3 μg/mg) by HPLC and LC‐ESI/MS/MS analyses. Our finding identified ferulic acid as a major phenolic compound in black rice bran, and supports the potential use of black rice bran as a natural source of antioxidant.