The effect of enzyme systems and processing on the hydrolysis of peanut (Arachis hypogaea L.) protein

In vitro protein digestion studies were carried out on raw and roasted peanut flour as the starting material in the production of peanut protein hydrolysate. Peanut flour was hydrolyzed with alcalase and alternately in a sequential digestion with pepsin-pancreatin, both for up to 24 h. The degree of hydrolysis (DH) at different times of hydrolysis was determined using the trinitrobenzenesulfonic acid (TNBS) method. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to indicate destruction of native protein units in the enzymatic digests.Hydrolysis with alcalase was very rapid for the first 6 h after which a plateau was reached, whereas that with pepsin–pancreatin was more gradual reaching a plateau after 12 h of hydrolysis. Raw peanut hydrolyzed with alcalase and pepsin–pancreatin had 23% and 21% DH after 24 h respectively, whilst roasted peanut hydrolyzed with alcalase had 21% DH, with the pepsin–pancreatin hydrolysate recording the highest value of 25% after 24 h of hydrolysis.SDS-PAGE results showed that raw peanut samples behaved differently from the roasted samples; increasing hydrolysis time reduced larger peanut protein subunits, with only peptides of <20 kDa visible after hydrolysis for raw peanut, and virtually no distinct visible bands for the roasted peanut after 3 h of hydrolysis.     

茶多糖酶法提取的优化条件及其对葡萄糖激酶活性的影响

为揭示茶多糖的高提取效率与其高活性之间的相关性,在系统考察胰酶作用条件和冰乙醇用量对其提取效率影响的基础上,采用正交实验对茶多糖的酶法提取条件进行了优化。结果表明,酶解条件和冰乙醇用量对茶多糖的提取效率有较大的影响,获得茶多糖高提取效率(54.70%)所需条件与获得高降糖活性茶多糖(葡萄糖激酶相对酶活比值达3.97)所需条件不同。     

活性炭静态吸附马氏珠母贝胰酶水解产物中氨基酸特性研究

采用胰酶酶解马氏珠母贝肉蛋白,研究了活性炭静态吸附前后酶解产物中氨基酸及各组分的变化情况。结果表明:在马氏珠母贝胰酶水解体系中,结合态和游离态芳香族氨基酸分别被吸附67.4%和42.3%,处于结合态的芳香族氨基酸更易于被活性炭吸附,并且活性炭吸附后,分子量较大组分的蛋白或多肽含量明显下降。     

Recovery of Components from Shrimp (Xiphopenaeus kroyeri) Processing Waste by Enzymatic Hydrolysis

ABSTRACT:  Industrial shrimp waste is a good source of protein, chitin, and carotenoids. In general, this waste is discarded with no attempt to use it, thus contributing to environmental pollution. This study was aimed at recovering the 3 main components of industrial shrimp waste, protein, chitin, and astaxanthin, using enzymatic treatment with Alcalase and pancreatin. An increase in the degree of hydrolysis (DH) from 6% to 12% resulted in 26% to 28% protein recovery. Alcalase was more efficient than pancreatin, increasing the recovery of protein from 57.5% to 64.6% and of astaxanthin from 4.7 to 5.7 mg astaxanthin/100 g of dry waste, at a DH of 12%. The enzymatic hydrolysis of the industrial waste from Xiphopenaeus kroyeri shrimp using Alcalase allowed for 65% protein recovery in the form of hydrolysates, in addition to providing suitable conditions for the recovery of astaxanthin and chitin.     

牛奶大分子蛋白的水解及其抗原性变化

目的: 将婴儿乳粉以不同的食品级蛋白酶水解, 降低牛奶的分子量, 考察牛奶酶水解产物过敏原性的变化。方法: 采用胃蛋白酶、胰蛋白酶和自制胰酶制品对婴儿奶粉进行酶解, 以快速蛋白质液相色谱测得酶解产物分子量分布和所占比例。通过实验动物主动、被动皮肤反应和口服致敏肠腔通透性变化观察不同酶水解后牛奶的过敏原性变化。结果: 快速蛋白质液相色谱结果表明蛋白酶水解牛奶后,牛奶蛋白分子量明显降低, 尤以自制胰酶对乳粉的水解程度最高(分子量<1 000 占92 %;1 000～10 000 占8 %)。胃蛋白酶、胰蛋白酶和胰酶水解产物可以显著抑制由牛奶蛋白引起的小鼠耳速发型主动皮肤过敏, 抑制率分别为51 %、83 %和86 %。小鼠同种及异种被动皮肤过敏反应实验中, 与未水解奶粉组比较, 同种皮肤过敏反应三种酶解产物炎性渗出降低率分别为29 %、70 %和82 %, 异种皮肤过敏反应的降低率分别为34 %、70 %和82 %。口服致敏小鼠肠腔通透性及分泌功能测定结果显示, 胰酶水解产物致敏小鼠的肠腔伊文思蓝渗出率比未水解前降低了27 %。结论: 酶水解后牛奶大分子蛋白物质降解, 其过敏原性有不同程度的降低, 尤以胰酶水解产物变化最为显著。     

利用猪新鲜胰脏降解猪血蛋白的条件研究靠

研究了猪新鲜胰脏提取胰酶以及胰酶粗提液降解猪血蛋白获取蛋白水解液的条件。结果表明:加入提取溶剂乙醇和激活和稳定剂CaCl2能提高胰蛋白酶的得率。在E/S=6000U/ml加入胰酶、底物浓度8%、pH8.0条件下,45℃水解时间12h,猪血蛋白的水解率较高。     

胰脂肪酶固定化及其水解天然黄油制备奶香底料的研究

利用吸附法将脂肪酶固定在三种阴离子树脂载体上,以大孔阴离子树脂D201为载体得到的固定化脂肪酶活性最大,且有较高的可操作性,重复使用3次,活性依然保留为原来的80%.用固定化酶催化天然黄油的水解反应,短时间内水解率可达到20%左右.用GC-Ms检测水解产物组成,检测到90多种挥发性成分.     

羊胰酶制备工艺优化

以研究羊胰脏提取胰酶工艺参数为目的。用低浓度异丙醇做提取剂,高浓度异丙醇做沉淀剂,在单因素基础上,运用均匀设计法研究激活时间、沉淀剂浓度、提取pH值和CaCl2对羊胰酶提取工艺的影响。胰蛋白酶、胰淀粉酶、胰脂肪酶活力和胰酶提取率为响应指标,通过偏最小二乘回归(PLS)分析法对胰酶制备工艺的影响因素进行优化组合,并建立了具有制备条件的数学模型。试验结果表明,羊胰酶制备最适条件为:激活时间12 h、沉淀剂浓度41%、提取pH值6.34和CaCl2 0.08%。此条件下验证实测值胰蛋白酶、胰淀粉酶、胰脂肪酶的活力和胰酶提取率分别为3 062.78 u/g、30.06 ku/g、32.37 ku/g和6.16%,与理论预测值的相对误差分别为8.11%、1.28%、3.55%和5.29%。进一步验证了数学二次多项式回归模型的适合性,PLS优化结果的合理性。     

胰酶固定化条件的优化与应用

使用海藻酸钠微球包埋法固定化胰酶,优化了反应条件,确定了海藻酸钠微球包埋法固定化的最佳条件。将海藻酸钠胰酶水溶液（3％海藻酸钠、0．7％胰酶）静置成胶液后滴入2％CaCl2溶液中制成微球,对制备后酶的特性进行了测定,固定化酶的最适反应温度为55℃,最适pH值为8．0,酶活力回收率为35．4％,10次反应后酶活力仍保持56％,贮藏49d后酶活力保持为初始活力的75．23％。利用固定化酶制备酪蛋白磷酸肽（CPPs）,并对CPPs促进钙吸收的性质进行了测定,结果表明,CPPs能有效地阻止磷酸钙沉淀的生成。     

双激活剂牛胰酶壳聚糖絮凝法制备工艺优化

采用Plackett-Burman设计对影响胰酶活力和提取率的13个因素进行筛选,有效筛选出主效因素(P＜0.05)：壳聚糖、CaCl2、胰腺与十二指肠配比和激活pH值。在此基础上,再运用均匀设计对以上4个显著因素的最佳水平范围进行研究,通过偏最小二乘法建立回归方程求解得到胰酶制备最适条件为壳聚糖用量0.17%、CaCl2用量0.06%、胰腺与十二指肠配比8.26:1、激活pH5.37。此条件下验证实测值胰蛋白酶、胰脂肪酶、胰淀粉酶活力和胰酶提取率分别为3408.71U/g、33.11kU/g、23.93kU/g和13.22%,与理论预测值的相对误差分别为7.15%、8.56%、10.63%、1.93%。Plackett-Burman设计和均匀设计相结合的方法在双激活剂胰酶壳聚糖絮凝法制备工艺中具有可行性。