油用牡丹籽粕蛋白及其酶解产物的功能性质研究

研究了油用牡丹籽粕蛋白(PoSMP)及其碱性蛋白酶酶解产物(AHs)的相对分子质量分布、溶解度、变性温度及温度和pH对其抗氧化性的影响。结果表明:PoSMP的亚基主要分布在62、45、34kDa和23 k Da处,且45、23 k Da条带对碱性蛋白酶具有良好的耐受性; pH为4. 5和3. 7时,PoSMP和AHs的溶解度最低,分别为(0. 92±0. 25)%、(8. 90±0. 32)%,在中性条件下均表现出良好的溶解性;两者的变性温度分别为67. 82℃和84. 70℃。此外,PoSMP在高温和p H为3. 0～9. 0时表现出良好的抗氧化性,AHs在高温和强碱性pH 11. 0条件下也具有优异的抗氧化性。试验证明了PoSMP和AHs具有较好的溶解性及抗氧化稳定性,有望作为添加剂或功能成分应用于食品及保健品领域。     

Production and properties of casein hydrolysate microencapsulated by spray drying with soybean protein isolate

The aim of this work was to encapsulate casein hydrolysate by spray drying with soybean protein isolate (SPI) as wall material to attenuate the bitter taste of that product. Two treatments were prepared: both with 12 g/100 g solids and containing either two proportions of SPI: hydrolysate (70:30 and 80:20), called M1 and M2, respectively. The samples were evaluated for morphological characteristics (SEM), particle size, hygroscopicity, solubility, hydrophobicity, thermal behavior and bitter taste with a trained sensory panel using a paired-comparison test (non-encapsulated samples vs. encapsulated samples). Microcapsules had a continuous wall, many concavities, and no porosity. Treatments M1 and M2 presented average particle sizes of 11.32 and 9.18 μm, respectively. The wall material and/or the microencapsulation raised the hygroscopicity of the hydrolysate since the free hydrolysate had hygroscopicity of 53 g of water/100 g of solids and M1 and M2 had 106.99 and 102.19 g of water/100 g of solids, respectively. However, the hydrophobicity decreases, the absence of a peak in encapsulated hydrolysates, and the results of the panel sensory test considering the encapsulated samples less bitter (p < 0.05) than the non-encapsulated, showed that spray drying with SPI was an efficient method for microencapsulation and attenuation of the bitter taste of the casein hydrolysate.     

富含支链氨基酸汉麻分离蛋白酶解物制备及其品质评价

以汉麻籽粕为原料,通过胃蛋白酶和风味蛋白酶分步酶解,辅助活性炭脱芳,制备富含支链氨基酸的汉麻分离蛋白酶解物,并以抗氧化性和溶解度评价其品质特性。结果表明:制备富含支链氨基酸的汉麻分离蛋白酶解物工艺中胃蛋白酶最佳酶解条件为料液比1∶5、酶添加量0. 9%、酶解温度37℃、酶解pH 2. 5、酶解时间5 h,风味蛋白酶最佳酶解条件为酶解温度50℃、酶添加量0. 8%、酶解p H 7、酶解时间4 h;经两步酶解后得到的汉麻分离蛋白酶解物(E-HPI)水解度为(33. 01±0. 43)%、A280为0. 321±0. 002;与汉麻分离蛋白(HPI)相比,E-HPI溶解度得到极大改善,p H 7时其溶解度为(83. 67±2. 45)%。氨基酸分析结果显示,E-HPI支链氨基酸含量为23. 37%,显著高于HPI中支链氨基酸含量。抗氧化研究结果显示,E-HPI的·OH清除率和DPPH·清除率相比HPI分别提高了1. 15倍和1. 58倍。     

Antioxidant activity of peptide fractions derived from cottonseed protein hydrolysate

BACKGROUND: Cottonseed protein is widely regarded as a potential source of nutrients for humans and animals, but it is mainly used as forage in China. In the present study, Neutrase was employed to hydrolyse cottonseed protein to produce a hydrolysate with antioxidant activity suitable for conversion to high‐value products. The antioxidant potential of the cottonseed protein hydrolysate (CPH) and its fractions was investigated using different in vitro methods. Furthermore, the amino acid composition of the CPH fractions was determined to evaluate the relationship between antioxidant activity and amino acid composition. RESULTS: The CPH prepared using Neutrase was separated into four fractions (I, II, III and IV) by gel filtration on Sephadex G‐25. All fractions were effective antioxidants, with fraction III (0.8–1.2 kDa) showing the strongest activity. The amino acid analysis showed that fraction III also had the highest total amino acid content (616.8 g kg^?1 protein) and was rich in Phe, His, Pro, Met, Ile and Cys compared with the other fractions. CONCLUSION: The results showed that the hydrolysate derived from cottonseed protein, particularly fraction III, could be a natural antioxidant source suitable for use as a food additive. Copyright © 2010 Society of Chemical Industry     

废革屑水解蛋白质的酚类改性研究

采用氧化镁和蛋白酶两步法处理铬鞣废革屑 ,得到水解蛋白质 ,然后用酚类物质对它进行改性。研究了各种因素 ,如酚类物质对水解蛋白质改性时的用量、反应液pH值、温度、反应时间等 ,通过测定反应液的吸光度和浊度 ,优选并确定了用酚类物质对水解蛋白质进行改性的条件。     

废革屑水解蛋白质的甲醛改性研究

采用氧化镁和蛋白酶两步法处理铬鞣废革屑 ,得到水解蛋白质 ,然后用甲醛对它进行改性。研究了各种因素 ,如甲醛用量、反应液 p H值、浓度、温度、反应时间等 ,通过测定改性蛋白质的黏度、皮粉吸收率和耐铬稳定性 ,优选并确定了用甲醛对水解蛋白质进行改性的条件。     

大豆蛋白水解产物性能的研究

对大豆蛋白水解产物的性能进行了研究。结果表明,其水解产物的黏度显著降低;具有良好的钙包溶性;在水解时间3~4 h时乳化稳定性最强;麦芽糊精、脱脂奶粉、乳清粉、蔗糖酯对大豆分离蛋白水解产物的乳化稳定性有增加作用。     

白木通籽分离蛋白的理化与功能性质研究

以白木通籽为原料,采用碱提酸沉法,制备白木通籽分离蛋白（API）,并对其理化性质与功能性质进行了分析。结果表明:白木通籽分离蛋白含17种氨基酸,其中谷氨酸和天门冬氨酸的含量相对较高,有贮藏蛋白的共性。苏氨酸为白木通籽分离蛋白的第一限制性氨基酸。通过SDS-PAGE分析,白木通籽分离蛋白的亚基分子量范围为25～35ku。圆二色性光谱分析表明,白木通籽分离蛋白的二级结构主要由β-折叠和无规则卷曲组成,含量分别为31.2%和36.6%。白木通籽分离蛋白的等电点在pH4～5之间,在此pH范围内,蛋白的溶解性和起泡能力均最低。      

韭菜籽蛋白的提取及抗氧化活性研究初探

以脱脂韭菜籽粉为原料,采用磷酸盐缓冲液法制备韭菜籽蛋白。以韭菜籽蛋白的提取率、DPPH·清除率及羟基自由基(·OH)清除率为指标,对提取温度、提取时间、pH及料液比四个因素各取三个水平,进行L9(34)正交实验,确定最优的制备工艺。最优的工艺条件如下:提取温度48℃,提取时间1.5h,pH7.5,料液比1∶10。在此条件下进行验证实验,测得韭菜籽蛋白的提取率为9.87%,在韭菜籽蛋白浓度分别为1mg/mL和2mg/mL时,对·OH和DPPH·清除率分别为73.37%和25.2%,说明采用磷酸盐缓冲溶液法制备得到的韭菜籽蛋白具有抗氧化活性。      

酸枣仁油脂质体温敏凝胶的制备

为了提高酸枣仁油的脑部生物利用度,增加其制剂稳定性与缓释性,将其制备为酸枣仁油脂质体温敏凝胶。通过优化制备工艺,使酸枣仁油脂质体包封率达73.8%,并将脂质体制备为胶凝温度为35~36℃的温敏凝胶,载药量为2.8%。该凝胶在30~33℃的鼻下部为液体,可流入手指难以触及的鼻腔嗅区粘膜,并在该区域受热胶凝黏附,以脂质体的形式缓释。     

Hypolipidemic effect of enzymatically extracted sunflower seed protein fraction

An attempt was made to enzymatically extract the protein fraction (PF) from sunflower seeds and investigate its dietary effect on the growth, plasma and tissue lipid profiles, plasma protein content, erythrocyte membrane lipid profile and organ weights of rats. Extraction of dehulled sunflower seeds in an aqueous medium in the presence of the enzyme pectinase at 50 ± 1 °C and pH 4.5 yielded a protein fraction with low residual chlorogenic acid and fibre contents. Rats fed the sunflower seed protein fraction showed a similar body weight gain and food efficiency ratio as rats fed casein. However, the different dietary proteins had different effects on plasma total cholesterol and triglyceride contents. The rats fed the sunflower seed protein fraction showed a significant decrease in plasma cholesterol (p < 0.02) and triglyceride (p < 0.02) concentrations compared to the casein‐fed rats. The PF‐fed rats also exhibited a significant difference in erythrocyte membrane phospholipids and phosphatidylcholine/phosphatidylethanolamine ratio. Rats fed the different dietary proteins did not show much variation in plasma protein content, liver and brain lipids and organ weights. These results demonstrate the hypolipidemic action of the sunflower seed protein fraction and that it can be considered a suitable edible protein like casein. © 2000 Society of Chemical Industry     

葵花籽蛋白水解物对水包油型乳状液物理和氧化稳定性的影响

利用碱性蛋白酶对葵花籽蛋白进行适度水解后,将葵花籽蛋白水解物(SSH)添加到以单甘酯作为乳化剂制备的乳状液中,通过测定乳状液的乳化活性、乳化稳定性、粒径、絮凝指数、凝结指数以及乳状液贮藏14 d过氧化值和丙二醛含量的变化,评价SSH对乳状液物理和氧化稳定性的影响。结果表明:添加SSH可显著提高乳状液的乳化活性、乳化稳定性、絮凝和凝结稳定性,显著降低乳状液的粒径;SSH添加量为1.0%时,乳状液具有较好的物理稳定性,同时又具有较好的氧化稳定性。     

不同方法提取茶籽蛋白及其抗氧化活性研究

以茶籽粕为原料,用碱法、盐法和缓冲液法提取茶籽蛋白,并测定其抗氧化活性。结果表明:盐法的茶籽蛋白得率和蛋白质含量均高于其他两种方法;盐法最佳提取条件为硫酸铵浓度0.005mol/L,料液比1∶50,时间180 min,pH 10;在盐法最佳提取条件下,茶籽蛋白得率为5.24%,蛋白质含量为82.65%。3种提取方法所得茶籽蛋白对DPPH自由基、羟自由基、Fe3+都具有抗氧化活性,当盐法所得茶籽蛋白在质量浓度8.0 mg/mL时,对DPPH自由基的清除率为74.78%,优于碱法和缓冲液法所得茶籽蛋白。     

水解蛋白来源的抗氧化肽研究进展

采用水解技术制备抗氧化肽可大大拓宽其来源。本文介绍了影响水解技术制备抗氧化肽的因素，综述了国内外在这一领域的研究进展，并展望了此种方法制备抗氧化肽产业化的可能性。     

超滤法浓缩富集牡蛎蛋白抗氧化活性肽

为研究牡蛎蛋白酶解产物中发挥抗氧化活性的肽片段,采用超滤的方法对其进行初步分离富集,测定了各级组分的体外抗氧化能力和氨基酸组成。结果表明:<4000u超滤液对羟自由基、DPPH自由基和超氧自由基清除活性的IC50值分别为17.29、2.82、7.02mg/mL,对肝脂质过氧化抑制作用的IC50值为14.40mg/mL,均低于原液和其他超滤组分;<4000u超滤液的还原力均高于同浓度的原液和其他超滤组分。经氨基酸分析,超滤后组氨酸、脯氨酸、甲硫氨酸、半胱氨酸、酪氨酸、色氨酸及苯丙氨酸的含量得到了富集。<4000u的超滤液经凝胶层析后,活性部分主要集中在550～3890u。