酶法制备脱脂鱼蛋白的初步研究

采用5种酶对脱脂鲢肉进行水解制备水解鲢蛋白。脱脂鲢肉是分别采用异丙醇、正己烷、乙酸乙酯3种溶剂萃取法进行脱脂后得到。分别用木瓜蛋白酶、枯草杆菌中性蛋白酶、枯草杆菌碱性蛋白酶、胰蛋白酶和复合蛋白酶对3种脱脂鲢肉及未脱脂鲢肉进行水解。试验结果表明，乙酸乙酯对鲢肉脱脂率最高，脱脂率为96．33％。复合蛋白酶为最适酶，乙酸乙酯脱脂鱼肉为最佳底物；在最佳水僻条件下：pH6．5，温度55℃，酶量3500U／g蛋白质，底物浓度（乙酸乙酯脱脂鲢肉：水）1：5，其水解度达到最大，为44．00％。     

沙蜇饮料基料酶解液酶解工艺的研究

以水解度为指标,选用胰蛋白酶、碱性蛋白酶、酸性蛋白酶、中性蛋白酶、风味蛋白酶和胃蛋白酶对沙蜇进行单酶水解,确定胰蛋白酶为水解用酶。通过正交实验确定胰蛋白酶的水解条件为：温度45℃、时间5．5小时、料液比1：4．5、加酶量255U／ml、pH7．5。实验表明,适宜条件下水解度为24．59％。水解液选用柠檬酸为除腥剂,处理后的水解液腥味和涩味都有大幅度降低。     

罗非鱼碎肉酶法制备蛋白胨的工艺研究

为探讨罗非鱼碎鱼肉酶法制备蛋白胨的加工工艺,采用正交试验的方法,分别研究了木瓜蛋白酶、AS.1398中性蛋白酶、复合蛋白酶水解罗非鱼碎肉制备蛋白胨的工艺条件。结果表明:木瓜蛋白酶的最佳水解工艺条件为pH6.5,温度65℃,水解时间4h,加酶量1250 U/g,蛋白胨得率达12.63%;AS.1398中性蛋白酶最佳水解工艺条件为pH 7.5,温度55℃,水解时间4 h,加酶量750 U/g,蛋白胨得率达13.25%;复合蛋白酶的最佳水解工艺条件为pH 7.0,温度50℃,水解时间4.5 h,加酶量850 U/g,蛋白胨得率达11.43%。     

复合酶提取牡蛎抗氧化肽的工艺研究

以牡蛎为原料,首先从木瓜蛋白酶、中性蛋白酶、碱性蛋白酶、胃蛋白酶、胰蛋白酶中筛选出胰蛋白酶为内切酶,以水解度为指标,得到最佳的酶解工艺条件:时间4h,温度50℃,pH8.0,料水比1∶2,加酶量3％(7 500 U/g),水解度为49.50％;同时以水解度为指标,得到外切酶风味蛋白酶的最佳酶解工艺:时间5h,温度50℃,pH8.0,料水比1∶2,加酶量3％ (450 U/g),实际水解度50.95％.最后,以清除羟自由基能力和水解度为指标,探讨内切酶(胰蛋白酶)和外切酶(风味蛋白酶)不同复合酶解方式的抗氧化能力.最终确定,复合酶解制备牡蛎抗氧化肽效果最好,其酶解条件为胰蛋白酶为3％(7 500 U/g)、风味蛋白酶加酶量为3％ (450 U/g),pH8.0,时间5h,料水比1∶2,温度50℃时,水解度高达53.94％,体外清除·OH的EC50为0.56 mg/mL.     

缢蛏蛋白肽制备工艺优化及其清除羟自由基作用

以缢蛏为试验材料,采用羟自由基清除率为评价指标,从胰蛋白酶、胃蛋白酶、木瓜蛋白酶、碱性蛋白酶和中性蛋白酶5种蛋白酶中筛选最适水解用酶,在单因素试验基础上使用响应面法优化酶解工艺条件,考察缢蛏蛋白肽的羟自由基清除能力并通过Sephadex G-15凝胶层析测定其分子质量分布。结果表明,碱性蛋白酶酶解制备的缢蛏蛋白肽清除羟自由基能力明显强于其他蛋白酶,优化后的碱性蛋白酶水解缢蛏蛋白工艺条件为底物浓度6mg/ml、加酶量3%、pH8.0、温度55℃、酶解时间4h,蛋白肽的羟自由基清除率为76.60%,IC50值为1.89mg/ml,蛋白肽中80%以上是分子质量小于1500Da的小分子肽。     

Optimization of the preparation of bioactive peptides from Sinonovacula constricta and its hydroxyl free radical scavenging activity

以缢蛏为试验材料,采用羟自由基清除率为评价指标,从胰蛋白酶、胃蛋白酶、木瓜蛋白酶、碱性蛋白酶和中性蛋白酶5种蛋白酶中筛选最适水解用酶,在单因素试验基础上使用响应面法优化酶解工艺条件,考察缢蛏蛋白肽的羟自由基清除能力并通过SephadexG-15凝胶层析测定其分子质量分布.结果表明,碱性蛋白酶酶解制备的缢蛏蛋白肽清除羟自由基能力明显强于其他蛋白酶,优化后的碱性蛋白酶水解缢蛏蛋白工艺条件为底物浓度6 mg/ml、加酶量3％、pH8.0、温度55℃、酶解时间4h,蛋白肽的羟自由基清除率为76.60％,IC50值为1.89 mg/ml,蛋白肽中80％以上是分子质量小于1500 Da的小分子肽.     

Ti鱼蛋白酶水解物的提取

用枯草杆菌中性蛋白酶（AS1398酶）提取Ti鱼蛋白酶水解物。酶水解条件由正交实验确定，即Ti鱼匀浆用AS1398酶350IU／ml在42℃下水解12h。水解液经活性炭吸附结合β－环糊精掩盖脱去苦味。生产性中试蛋白质回收率78．80％，喷雾干燥所得制品产率为14．91％。制品呈白色粉末，无苦味；蛋白质含量88．26％，必需氨基酸占总氨基酸43．61％，氨基酸间比例合理。Ti鱼蛋白酶水解物为优质蛋白质制品。     

紫菜降血压肽酶法制备工艺的优化

摘要：降血压肽又称为血管紧张素转化酶抑制肽,是具有降血压活性的生物活性肽,对高血压患者有显著疗效。为探讨从紫菜中制备降血压肽的酶法工艺,本实验选用AS．1398中性蛋白酶、胰蛋白酶、复合酶、木瓜蛋白酶、碱性蛋白酶、风味蛋白酶等6种蛋白酶分别对紫菜进行酶解,通过对其酶解液的ACE抑制活性和水解度的比较,发现采用AS．1398中性蛋白酶酶解的产物ACE抑制活性最高。对AS．1398中性蛋白酶的酶解工艺进一步优化,确定其最佳酶解工艺为：温度50℃、pH值7．5、加酶量E／S10000U·g^-1。在此条件下,酶解4h和10h的酶解产物抑制活性最高均达70％以上,并发现紫菜酶解液的ACE抑制率与水解度的增长不成显著的线性关系。     

翡翠贻贝双酶水解法的建立

研究了双酶法水解技术水解翡翠贻贝并制作海鲜调味料。研究结果表明：（１）水产品快速自溶技术不能应用于翡翠贻贝贝肉蛋白的水解;（２）翡翠贻贝贝肉蛋白可以用外源酶对其水解;（３）枯草杆菌中性蛋白酶和胃蛋白酶都可以对贝肉蛋白水解;（４）利用正交试验分别确定了两种酶的最适水解条件并用双酶法水解新技术对贝肉蛋白水解;蛋白质水解率达到８２％;（５）试验中确定的酶的水解条件为枯草杆菌中性蛋白酶：ｐＨ７．５,温度４     

鲢酶解物对羟自由基的清除作用

通过测定酶解物对Fenton体系产生的羟自由基的清除效果，从胰蛋白酶、木瓜蛋白酶、胃蛋白酶、枯草杆菌蛋白酶和复合蛋白酶5种酶中，筛选出木瓜蛋白酶和胰蛋白酶作为酶解鲢制备具有较高清除羟自由基活性酶解物的理想水解酶；用正交试验L9(3^4)对两种酶的水解条件进行了优化，并对最佳酶解条件下得到的酶解物进行Sephadex G-25凝胶柱分离，洗脱液分别在波长280nm处比色，测定酶解物中主要抗氧化活性肽的分子量分布。结果表明，木瓜蛋白酶在温度50℃、酶解时间15min、pH=6．5、酶质量分数1．50％、底物：水=1：2的水解条件下，酶解物对羟自由基清除效果较好，清除率为88．2％；胰蛋白酶在温度55℃、酶解时间60min、pH=8．0、酶质量分数0．25％、底物：水=1：2的水解条件下，酶解物对羟自由基清除效果较好，清除率为84．2％。木瓜蛋白酶酶解物在最大洗脱峰时有最大羟自由基清除率峰，清除率为95．1％，在最大峰处酶解物中活性肽的分子量为2．2kDa；胰蛋白酶酶解物在最大洗脱峰时也有最大羟自由基清除率峰，其清除率为89．6％，该峰处活性肽的分子量为14．2kDa。     

虾头内源酶酶解虾肉产物的ACE抑制活性及其降低原发性高血压老鼠血压的效果

虾头内源酶酶解虾肉产物的ACE抑制活性及其降低原发性高血压老鼠血压的效果=Angiotensin I converting enzyme inhibitory activity of shrimp meat hydrolysate by endogenous enzymes from shrimp head and its antihypertensive effects on spontaneously hypertensive rats［刊,中］/洪鹏志（广东海洋大学食品科技学院,湛江524088）,曹文红,郝更新,章超桦//水产学报,—2007,31(1).-76～83 在pH 7.35、温度57.2 ℃、水解时间4 h、虾肉/虾头为1∶1,底物浓度为20%（W/V）的条件下,利用虾头的内源酶酶解虾肉（南美白对虾）,制备了具有血管紧张素转化酶（ACE）抑制活性的酶解产物,其对ACE的抑制率为41.9%（2 mg·mL-1）。通过凝胶过滤层析测定出酶解产物的分子量分布较广,在7.4×104至29.7之间。分子量在2.7×103以下的凝胶层析组分占酶解产物氨基酸总量的83.1%。收集的高活性组分分子量在959～338之间,其IC50为0.32 mg·mL-1苯丙氨酸、疏水氨基酸（亮氨酸、异亮氨酸和缬氨酸）和芳香族氨基酸（脯氨酸、酪氨酸和色氨酸）占氨基酸总量的42.33%。体内试验的结果显示,南美白对虾的虾肉虾头内源酶酶解产物经灌喂原发性高血压老鼠后显示较强的降血压活性。 图4表2参13 关键词：南美白对虾;内源酶;血管紧张素转化酶抑制活性;抗高血压作用 E-mail:zhangch@gdou.edu.cn     

不同酶解条件对鳀鱼蛋白水解物苦味及氨基酸组成的影响

研究了不同酶解的鱼可溶性产物苦味及呈味氨基酸组成的差异 ,以及其水解时间、水解率对苦味的影响。结果表明 ,随着酶解时间延长和水解率的提高 ,几种水解液的苦味值都有不同程度增强。胃蛋白酶和胰蛋白酶的复合水解液表现出随水解时间的延长 ,水解率提高明显 ,苦味强度上升平缓。当水解率从4 2 %提高到 78%时 ,苦味值只提高了 2 ,水解液总的苦味分值为 3.5 ;枯草杆菌蛋白酶水解 2h后苦味分值急剧提高 ,水解 4h后苦味分值达到 6,水解液味道很苦 ,水解率从 32 %提高到 62 %时 ,苦味分值提高到了 7,水解液总的苦味值为 8.5。两种方法水解获得的可溶性产物氨基酸及必需氨基酸组成含量接近 ,但胃蛋白酶、胰蛋白酶复合水解的可溶性产物具有更高的氨基酸分值 ,主要鲜味氨基酸含量略高于枯草杆菌蛋白酶水解产物 ,苦味氨基酸则相反。     

Enzymatic Hydrolysis of Catfish (Pangasius hypophthalmus) By-Product: Kinetic Analysis of Key Process Parameters and Characteristics of the Hydrolysates Obtained

In this study, kinetic evaluation of enzymatic hydrolysis of catfish (Pangasius hypophthalmus) by-product meat was conducted. The effects of key factors such as type of proteases (neutrase, papain, and bromelain), enzyme to substrate ratio (E/S), substrate concentration, and extent of hydrolysis on process efficiency, properties and functionalities of hydrolysates were evaluated. The results demonstrated that, for catfish shredded meat, bromelain and papain had higher affinity than neutrase. Kinetics parameters V_m and K_m of neutrase, papain, and bromelain were 4.486, 9.060, and 18.249 μM/min and 35.433, 6.582, and 7.034 g/l, respectively. Optimal E/S ratios of neutrase, papain, and bromelain were estimated to be 0.92, 2.76, and 3.31 mg/g. At optimal E/S, the highest possible substrate concentrations were found to be 108.4 g/l for neutrase, 36.2 g/l for papain, and 135.8 g/l for bromelain. Both kinetics study and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed that bromelain and papain had higher proteolytic activity toward catfish protein than neutrase. A significant increase in antioxidant activity of hydrolysates was observed with neutrase and papain hydrolysate, but not with bromelain. The results could be helpful for industrial processors to develop an efficient process for catfish by-product valorization.     

木瓜蛋白酶在制取斑鰶鱼蛋白中的应用

为确定木瓜蛋白酶酶解斑鰶鱼的条件。研究了酶解温度、酶浓度、酶解时间、加水量、pH值对斑鰶鱼氨基氮含量和总氮得率的影响。结果表明：温度小于55℃。随着酶解温度的提高、酶浓度的增加、酶解时间的延长斑鰶鱼酶解液氨基氮含量和总氮得率均增加;pH值对水解效果及氮回收率影响不大。综合考虑,最佳水解条件为：温度55℃。加酶量6．0‰。酶解时间1．5h．原料：水=1：2．5,pH值6．8。此时。氨基氮生成率达26．7％。总氮得率2．28％。     

紫菜活性肽复合酶法制备与清除羟自由基作用

以条斑紫菜为原料,利用胰蛋白酶和木瓜蛋白酶组成的复合酶水解紫菜蛋白制备生物活性肽并研究清除羟自由基作用。采用单因素试验考察胰蛋白酶与木瓜蛋白酶的比例、底物质量浓度、酶用量、水解温度、水解时间、pH对羟自由基清除率及水解度的影响,响应面法优化酶解条件,SephadexG-15凝胶层析法测定活性肽的分子质量分布。试验结果表明,复合酶最佳酶解工艺条件为胰蛋白酶与木瓜蛋白酶复合酶比例1.67,底物质量浓度20mg/mL,酶用量1.67%,pH 7.0,温度55℃,酶解4h,紫菜活性肽对羟自由基的清除率为80.6%,清除率为50%时的质量浓度为0.744mg/mL,分子质量大多分布于500～1500ku。     

乙醛、对苯二甲酸、乙二醇对鲢、草鱼的联合毒性

实验按毒性单位1：1：1设计，研究乙醛、对苯二甲酸、乙二醇等化纤污水中主要污染物对鲢、草鱼的稚鱼和幼鱼的联合毒性。实验结果表明，乙醛＋对醛二甲酸＋乙二醇对鲢的稚鱼和幼鱼的96hLC50值分别为21300．6和27438.8mg/L；对草鱼的稚鱼和幼鱼的96gLC50值分别为27387．3和25606．2mg/L。联合毒性效应均表现为相加作用。     

Preparation and Characterization of Protein Hydrolysates From Little Loligo Squid (Uroteuthis chinensis)

Research on the little loligo squid (Uroteuthis chinensis) protein hydrolyzed by papain and Flavourzyme and characterization of hydrolysates was carried out in this article. The optimum hydrolysis conditions of papain were obtained by orthogonal experiments, and the influence factors on the degree of hydrolysis such as enzyme/substrate ratio, hydrolysis time, pH, and temperature were investigated. The effect of Flavourzyme on the degree of hydrolysis was also studied. The characteristics of freeze-dried hydrolysates such as yield, moisture, nitrogen recovery, molecular mass distribution, and amino acid composition were determined. The results showed that papain and Flavourzyme could hydrolyze the little loligo squid protein efficiently, and the degree of hydrolysis was up to 25.82% under the optimum hydrolysis conditions. The average molecular mass of hydrolysates obtained with papain and Flavourzyme was 1,246 Da, and the low molecular mass peptides were the main fraction of hydrolysates. The yield, moisture, and nitrogen recovery of freeze-dried hydrolysates was 19.8, 4.4, and 74.2%, respectively. Compared with suggested patterns of amino acid requirements by the Food and Agriculture Organization of the United Nations/World Health Organization (FAO/WHO), the hydrolysates of the little loligo squid had high nutritional value, and was a potential nutritious supplement used in various food products.     

Protein Dispersions and Hydrolysates from Shark (Isurus oxyrinchus)

Manually-deboned muscles of shark (Isurus oxyrinchus) were ground and then washed sequentially with water, 0.5% NaCl and 0.5% NaHC0₃ solutions. Washed myofibrillar proteins were dispersed in water and then acidified. Dispersions so obtained were stable to heat treatment at 100°C followed by centrifugation at 5000 x g, as approximately 90% of proteins remained in solution. The acidified dispersions had low solubility in the pH range of 5 to 8, but were highly soluble under other pH conditions. Apparent viscosity of dispersions was dependent on temperature, pH and protein concentration. The amino acid composition and calculated protein efficiency ratio (PER) of washed proteins were similar to that of the original meat; howevcr, over 85% of free amino acids were removed upon aqueous washings of the meat. Hydrolysates obtained via an Alcalase-assisted process from the original shark muscles or washed myofibrillar proteins exhibited unique functional characteristics with respect to their water-holding capacity and emulsifying properties.     

甲壳胺和N－亚甲基甲壳胺对贻贝酶解液中氨基酸吸附性研究

报道了甲壳胺（ｃｈｉｔｏｓａｎ）及Ｎ－亚甲基甲壳胺（Ｎ－ｍｅｔｈｙｌｅｎｅｃｈｉｔｏｓａｎ）对贻贝酶解液中各种氨基酸吸附情况。在一定ｐＨ（６．０）及浓度（９４５ｍｇ／ｋｇ）下：（１）甲壳胺对贻贝酶解液中各种氨基酸均有吸附，其中，对Ｔｙｒ，Ｐｈｅ，Ｈｉｓ，Ａｒｇ，Ａｓｐ及Ｇｉｕ的吸附率较高；（２）Ｎ－亚甲基甲壳胺对贻贝酶解液中Ｈｉｓ，Ａｒｇ，Ｔｙｒ，Ｉｌｅｕ，Ｍｅｔ及Ｌｙｓ吸附率较高：（３）甲壳胺和Ｎ－亚甲基甲壳胺对贻贝酶解液中总氨基酸的吸附率分别为１２．９４％和１１．７０％。