利用牡蛎制作海鲜调味汁的试验

研究了混合酶水解牡蛎蛋白质的技术条件，并和单酶水解结果进行了比较。结果表明，混合酶水解可提高水解率和水解液中氨基态氮(AAN)的含量，同时改善了水解液风味。     

扇贝裙边氨基酸营养粉的制备工艺研究

为了对扇贝裙边进行综合利用，本文选择由中性蛋白酶、胰蛋白酶和复合蛋白酶3种酶组合成3对混合酶对扇贝裙边进行酶水解实验，以水解液中游离氨基酸态氮为考察指标，采用正交实验设计研究了加酶量、酶解时间、酶解温度及酶的种类对酶解效果的影响，从而优化了扇贝裙边的酶法水解工艺条件。以最佳水解工艺条件获得的酶解液经喷雾干燥制成的氨基酸营养粉，经检测，其粗蛋白含量为82.89%，粗脂肪含量为1.55%，总糖含量为6.82%。该氨基酸营养粉中氨基酸种类齐全，每100g粗蛋白中氨基酸总量达79.06%，其中游离氨基酸总量达51.53%。     

酶解扇贝裙边制备复合氨基酸螯合钙的研究

扇贝裙边富含蛋白质、脂质等营养成分。为了高值化利用扇贝裙边，本研究选用中性蛋白酶、动物蛋白酶、风味蛋白酶、木瓜蛋白酶和酸性蛋白酶5种酶，以酶解液中游离氨基酸态氮为考察指标，对扇贝裙边进行酶解工艺条件探讨。首先，将5种酶制成复合蛋白酶进行正交实验，确定最佳酶解时间、温度、pH及加酶量，经检验，氨基酸转化率为77%；然后，通过实验确定CaCl2为最适钙源，以贝壳为原料，通过水飞法和酸法转化可制得贝壳源CaCl2。将扇贝裙边酶解液中复合氨基酸与来源于贝壳的钙螯合制备复合氨基酸螯合钙，以正交实验筛选出最佳螯合条件。经检验，该螯合反应螯合率达92%。     

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。     

胰蛋白酶水解虾头壳制备钙结合肽的工艺条件优化研究

在单因素试验研究时间、底物浓度、pH,酶浓度和温度对蛋白水解度和酶解液中可溶性钙含量的影响基础上,通过响应面分析法对酶解条件进行了优化,得出最佳酶水解工艺条件为:底物浓度10%,pH 7.4,温度50℃,酶添加量1.39%,水解5h.在此条件下,酶解液水解度为29.0%,可溶性钙含量为176.4 mg/ml,水解液经凝...     

蟹酱的生产工艺技术

本文叙述了以低值小杂蟹为原料,用正交试验的方法,以氨基酸态氮、VBN、苦味为指标,探讨出用木瓜蛋白酶水解的适宜工艺(pH7,70℃,酶量0.3％,时间4h),采用其中上层水解液添加各种辅料和增稠剂生产蟹酱的工艺技术。     

不同酶解条件对Ti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Ti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42％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。     

缢蛏肉的蛋白酶水解工艺研究

实验研究了用枯草杆菌中性蛋白酶水解缢蛏肉的工艺条件,通过单因素试验和正交实验,得出了最适水解工艺条件为加酶量2.4％,水解温度50℃.料水比1:3。pH值为中性,时间为6h.水解产物的水解率和总的氮收率分别为42.46％和83.04％。水解液经脱腥等处理后可用于复合调味料和营养口服液的生产。     

采用超滤技术分离扇贝边酶解液

以聚砜中空纤维为膜材料的超滤装置对扇贝边酶解液进行分离,分析酶解液超滤分离过程中的影响因素,如操作压力、温度、料液pH、体积浓度比率(VCR)等因素对膜透过速率的影响。结果表明,控制操作压力在0.05～0.10MPa,温度40～43℃,料液pH7.0左右,并在超滤过程中采用间断循环清洗的方法,可提高膜分离效率。经超滤的酶解透过液在色泽、风味、澄清度等方面均理想,营养成分保持较好,氨基酸态氮保存率较高,可达92.2%。     

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。     

Rheological Behavior of Protein Hydrolysates from Papain-treated Male Gonad of Scallop (Patinopecten yessoensis)

ABSTRACT

In the present study, the rheological behavior of hydrolysates from scallop male gonad hydrolysates (SMGHs) was studied. The hydrolysates were obtained from scallop male gonads (SMGs) using papain. The changes in molecular mass of proteins in SMGHs were determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The results showed that the proteins of SMGs were significantly degraded after hydrolysis with papain. The degree of hydrolysis reached to 17.8% and 20.8% for SMGHs treated by papain at 300 and 3,000 U/g protein, respectively. The SMGHs exhibited a weak strain overshoot behavior as well as non-Newtonian shear thinning flow behavior. Moreover, the rheological properties of SMGHs possessed a papain dose-dependent manner. These results suggest that SMGHs could be applied as a potential gelling and thickening agent in food formulations.     

响应面法优化中性蛋白酶酶解海湾扇贝副产物制备抗氧化酶解物研究

采用响应面法优化中性蛋白酶酶解海湾扇贝(Argopecten irradias)副产物蛋白制备抗氧化酶解物工艺。以DPPH自由基清除率和还原能力为响应值,在底物浓度、温度、时间、酶与底物比4个单因素实验基础上,优化确定3个显著性因素。获得实验条件下最佳制备工艺为:底物浓度25 mg·mL^-1、温度50℃、时间3.8 h、酶与底物比1.5%。在此条件下,实验验证酶解海湾扇贝副产物蛋白制备抗氧化酶解物的DPPH清除率为81.93%(预测值为83.19%),还原能力为58.12%(预测值为58.92%),DPPH自由基清除率和还原能力的IC 50值分别为0.264 mg·mL^-1和3.136 mg·mL^-1,且表现出较强的抗氧化活性。研究表明,优化后的回归模型用于预测中性蛋白酶酶解海湾扇贝副产物蛋白制备抗氧化酶解物是可行的。     

鲣鳔蛋白抗氧化酶解物制备工艺

为有效提高鲣鳔蛋白的附加值,研究以DPPH自由基清除率为抗氧化活性评价指标,采用蛋白酶酶解制备活性多肽的工艺,选用菠萝蛋白酶、复合蛋白酶、碱性蛋白酶、木瓜蛋白酶、胃蛋白酶、胰蛋白酶、中性蛋白酶7种酶在各自最适的条件下酶解,筛选出复合蛋白酶为最适用酶,通过单因素实验分别研究加酶量、溶液初始p H、酶解温度和时间对酶解物抗氧化活性的影响,在此基础上,根据响应面法优化鲣鳔抗氧化酶解物的制备工艺。结果显示,最佳酶解工艺条件为加酶量8.53 U/mg,p H 5.54,温度50.03°C,时间5.07 h。此外,利用超滤法对最佳条件下制备的酶解物进行初步分级,得到分子质量分别为大于10 000 u、3000~10 000 u和小于3000 u的3段组分,且这3段组分对DPPH自由基的半抑制浓度IC50值分别为0.64、0.52和0.37 mg/m L。研究表明,最优条件下制备的酶解物的DPPH清除率达72.00%,与模型预测值71.60%接近,且其中小于3000 u的组分具有较强的DPPH自由基清除活性。     

Optimization of Protein Recovery During Hydrolysis of Yellowfin Tuna (Thunnus albacares) Visceral Proteins

Protein hydrolysates were prepared from yellowfin tuna viscera using Alcalase®. Response surface methodology (RSM) was applied to study the effect of independent variables, enzyme activity, temperature, and time on the protein recovery (PR) as the response. The coefficient of determination (r² = 98%) was satisfactory, and the lack of fit test showed a non-significant value for the PR model equation, indicating that the regression equation was adequate for predicting the PR under tested combinations of values. Enzyme activity at 79.9 AU/kg protein, temperature at 59.9°C, and the time of 105 min were found to be the optimum conditions to reach the highest PR (85%). Considerable soluble protein was released with increasing degree of hydrolysis (DH). The yellowfin tuna visceral hydrolysates' amino acids profiles showed high essential amino acids content, although lysine, methionine, and phenylalanine were limited. In addition, the results showed that with increasing hydrolysis time, the amino acids increased. Yellowfin tuna visceral hydrolysates were rich in flavor amino acids which can be used as a taste enhancer.     

Optimization of the Enzymatic Hydrolysis Assisted by Ultra-high Pressure Processing of Alaska Pollock Frame for Improving Flavour

ABSTRACT

In order to improve the flavor of aquatic enzymatic hydrolysate, this study determined the effect of ultra-high pressure processing (UHP) coupled with enzymatic hydrolysis on the flavor of Alaska pollock frame (APF) hydrolysates. The optimal conditions for UHP enzymatic hydrolysis were as follows: pressure time was 60 min, pH value was 7.5, and pressure was 150 MPa. The content of soluble peptide, total-free amino acid, and delicious amino acid (DAA) content of atmospheric pressure and UHP hydrolysates were 11.37 vs 16.70 mg/mL, 5 528 vs 6 234 mg/100 g, and 2145 vs 2411 mg/100 g, respectively. The major compounds in the enzymatic hydrolysates of UHP included seven types of ketones (18.31%), 8 types of aldehydes (6.35%), 3 types of alcohols (2.61%), one type of ester (0.38%), and one type of furan (7.89%). The results of electronic tongue (e-tongue) demonstrated good agreement with gas chromatography-mass spectrometry (GC-MS) analysis. In conclusion, UHP enzymatic hydrolysis can be a potential tool to improve the flavor compounds of hydrolysates.     

The Feasibility of Increasing Lipid Extraction in Tilapia (Oreochromis niloticus) Waste by Proteolysis

ABSTRACT

The aim of the present study was to evaluate the feasibility of increasing lipid extraction in tilapia (Oreochromis niloticus) waste using different enzymes and to minimize the periods of hydrolysis to evaluate the performance of the lipid fractions. When processing waste tilapia, commercial enzymes were added that were composed of neutrase and alcalase acting at different hydrolysis times to produce the best yields. The treatment proved feasible for obtaining the protein hydrolysates. The type of enzyme and the hydrolysis time determined the degree of fractionation. The enzymes performed well, and the highest efficiency occurred within 2 h of hydrolysis. By fractionating, the obtained by-products can be applied in the preparation of feed, as the lipid fraction treatments yielded significant amounts of polyunsaturated fats and suitable n-6/n-3 ratios.     

Odor Modification in Salmon Hydrolysates Using the Maillard Reaction

The aim of this work was to study the effect of adding sugar during proteolysis to promote the Maillard reaction and mask the initial fish odor and off-flavors generated. An experimental design, based on the Doehlert plan, was used to study the influence of hydrolysis conditions (time, temperature, sugar, and antioxidant addition) on the odor characteristics of hydrolysates, soluble protein levels, and amino acid content. Results showed that the lowest level of sugar (10 g of D-xylose added to 1 kg of by-products) was enough to develop a grilled odor in hydrolysates. In the hydrolysis conditions used—i.e., enzyme inactivation at 95°C for 30 min—hydrolysis temperature had no effect on grilled odor production but significantly affected the soluble protein fraction, as did hydrolysis time. Soluble protein content and essential amino acid content increased with the enzymatic reaction but were not modified by adding sugar. Hydrolysis conditions that promote Maillard reactions while keeping a nutritional balance have been identified.