天龙混合酶最佳酶解工艺研究

研究天龙混合酶的最佳酶解工艺,使这一动物类中药得到更好的发展利用。选择"酶解温度、酶解时间、pH值、加酶量"四个因素,设计L_(16)(4)~4正交表进行正交试验,以蛋白质水解度为指标,确定天龙混合酶的酶解最佳条件。正交试验得A_4B_4C_4D_4的蛋白质水解度最高,由正交试验得到45℃下、pH值=8.5、培养时间5 h、加酶量2500U为最佳工艺,并确定影响程度大小:酶解温度酶解pH值酶解时间加酶量。     

重组色氨酸合成酶催化合成5-羟基色氨酸

利用重组色氨酸合成酶催化合成5-羟基色氨酸,考察了pH、反应温度、底物摩尔比和底物浓度对色氨酸合成酶酶活的影响。最佳转化条件为：反应温度为35 篊,pH为9,5-羟基吲哚与工业角蛋白水解氨基酸液中L-丝氨酸的适宜底物摩尔比为1.1: 1,底物工业角蛋白水解氨基酸液中L-丝氨酸最适合浓度为200 mmol/L,反应达到平衡时间为18 h,底物L-丝氨酸摩尔转化率达到86%。     

废旧皮革制品水解工艺研究

为了解决废旧皮革制品潜在的污染环境问题并使其资源化,采用正交实验的方法,利用水热反应釜通过加压水解研究了温度、时间、液固比、催化剂种类和用量对皮革水解率的影响。实验结果表明,温度、时间与催化剂都对水解率有较大影响。在最佳条件下,草酸催化废皮革水解率可达82%,Na OH催化废皮革水解率可达76%。     

酶解对热反应番茄牛腩香精风味的影响

以牛肉酶解液为原料,通过热反应制备番茄牛腩风味香精。通过单因素实验和正交实验探讨了不同的酶解工艺对热反应番茄牛腩香精风味的影响,通过感官评价结合酶解液的水解度确定最佳的酶解条件为:风味蛋白酶在牛肉与水质量比为3∶4、加酶量为0.10%、酶解温度45℃、酶解时间3 h、自然pH下酶解牛肉。此时牛肉的水解度可达4.45%。以此制备的番茄牛腩香精风味最好,仿真性高,回味持久。     

酶解对热反应番茄牛腩香精风味的影响研究

以牛肉酶解液为原料,通过热反应制备番茄牛腩风味香精。通过单因素实验和正交实验探讨了不同的酶解工艺对热反应番茄牛腩香精风味的影响,通过感官评价结合酶解液的水解度确定最佳的酶解条件为：风味蛋白酶在牛肉与水质量比为3∶4、加酶量为0.10%、酶解温度45℃、酶解时间3h、自然pH下酶解牛肉。此时牛肉的水解度可达4.45%。以此制备的番茄牛腩香精风味最好,仿真性高,回味持久。     

正交实验法优化地龙粉混合酶酶解工艺

探索了地龙粉混合酶(弹性蛋白酶和胰蛋白酶)酶解最佳工艺。在单因素实验基础上,采取正交实验对地龙粉进行酶解。以酶解时间、酶解温度、pH、加酶量为自变量,以地龙粉水解度为因变量,采用L9(43)正交实验表进行实验。各因素对实验结果影响顺序为:CBDA。最佳酶解工艺条件为酶解时间8h,酶解温度55℃,pH=8,加酶量3 000 U,水解度达52.96%。     

酶解血粉制备氨基酸水溶肥工艺条件优化

为资源化利用动物血液,以血粉为原料制备氨基酸水溶肥。通过单因素实验研究液料比、原料预处理温度、蛋白酶种类及组合酶比例等因素对血粉蛋白酶解效果的影响;通过正交实验考察温度、酶制剂添加量、p H和时间对血粉蛋白酶解效果的影响。结果表明：血粉的最佳酶解工艺为液料体积质量比6 mL/g、温度55℃、组合酶添加量3.0%（组合酶中蛋白酶B与风味蛋白酶质量比为2∶1）、p H 8.0、时间12 h;在该工艺条件下,血粉蛋白水解度为67.26%,酶解液中19种游离氨基酸质量分数为6.39%,分子量在1 046 Da以下的多肽占比达到99.59%。通过对血粉酶解工艺的优化,提高了血粉蛋白的水解度,增加酶解液中氨基酸含量,为蛋白酶酶解血液制备氨基酸水溶肥的过程控制及规模应用提供理论指导。     

均匀设计优选双酶法分步水解甲鱼蛋白质最佳条件

采用木瓜蛋白酶、胰蛋白酶2种酶分步水解技术,对甲鱼蛋白质进行水解.利用均匀设计法研究上述2种酶分步水解甲鱼蛋白质的最佳工艺条件为:原料∶水=1∶3.5,木瓜蛋白酶用量18.0 g·kg-1,温度50 ℃,pH值6.9,水解时间5.5 h;而胰蛋白酶用量28.0 g·kg-1,温度50 ℃,pH 7.5,水解时间4 h.所得水解液的氨基氮含量为7906.5 mg·kg-1,水解液游离氨基酸的含量为626.7 mg·(100 mL)-1,其中必需氨基酸的含量为211.35 mg·(100 mL)-1.     

季铵化水解小麦蛋白质的合成

季铵化水解小麦蛋白质以小麦蛋白粉为原料,经过酶水解和季铵化两个步骤合成。通过实验考察酶催化剂的种类、反应温度、反应时间、反应配比等反应条件对水解及季铵化过程的影响,得到一条切实可行且相对高效的合成路线。     

酶法提取葡萄籽中蛋白质的工艺研究

以葡萄籽为原料,采用酶法对葡萄籽中蛋白质进行提取,探讨酶用量。料液比,提取温度,pH值,提取时间等5个因素对葡萄籽蛋白质提取率的影响。正交试验结果表明,在葡萄籽蛋白质的等电点pI=3．80时,各因素对酶法提取葡萄籽蛋白的影响次序为：浸提温度〉料液比〉pH〉浸提时间。木瓜蛋白酶提取葡萄籽蛋白质的最佳工艺条件为：浸提时间40min,料液比1：20（g／mL）,pH7．00,浸提温度40℃,酶用量0．8000g,在此最佳工艺条件下,葡萄籽蛋白质的提取率可达89．94％。     

碱性蛋白酶水解林蛙卵粕蛋白的工艺条件优化

研究了碱性蛋白酶水解林蛙卵粕蛋白制备混合氨基酸的工艺,分析了反应温度、酶加量、底物浓度和反应时间对蛋白水解度的影响.通过单因素实验和正交实验确定碱性蛋白酶水解林蛙卵粕蛋白的最佳工艺条件为:反应温度60℃、酶加量2000 U·g-1、底物浓度4％、反应时间120min,此时的蛋白水解度为10.18％.     

Determination of processing conditions for obtaining a pepitona (Arca zebra) hydrolysate for human consumption

For the purpose of obtaining two protein hydrolysates from peptiona (Arca zebra), to be used as nutritional ingredients in accepted food items destined for human consumption, the enzymes bromelain and papain were studied. The effect of adding each of these proteases, on the rate of hydrolysis and conversion extent of insoluble pepitona protein to soluble nitrogen, were examined. Distilled water was added to the raw material to give a 2:1 ratio of solvent to pepitona, and mixed to produce a slurry at a pH of 6.4-6.5, with a total nitrogen value of 0.97% (w/v). Optimum conditions of hydrolysis were found to be two hours at 40 degrees C for both enzymes, at a pH of 7 and 0.3 g enzyme/100 g pepitona for papain, and a 0.2 g enzyme/100 g pepitona at pH 6.4 normally found in pepitona in the case of bromelain.     

Enzymatic modification of proteins of commercial sesame meals (Sesamum indicum, L.)

Sesame (Sesamum indicum, L.) is one of the most important oilseed crops in Venezuela. However, the low solubility of the flour made of commercial meals does not allow its use in the preparation of fluid foods. To solve this situation, the alternative of solubilizing the sesame proteins by an enzymatic method, using commercial proteases, was studied. Hydrolysis was carried out with two types of bacterial proteases: neutrasa 0.5L, and alcalase 0.6L. Basically, the process consisted of milling and sieving the sesame cake (60 mesh), concentrating the proteins by solubilizing them at a pH of 9.5, and then precipitating at a pH of 4.5. Proteins were hydrolyzed by an enzymatic method, and the hydrolysates freeze-dried and spray-dried. Optimal conditions of hydrolysis using neutrase 0.5L at a pH of 7 were: 6% substrate concentration, 3% enzyme:substrate ratio, temperature 50 degrees +/- 1 degree C, and hydrolysis degree of 8%. When alcalase 0.6L was used at a pH of 8, optimal conditions were: 8% substrate concentration, 2.3% enzyme:substrate ratio, temperature 58 degrees +/- 1 degree C, and hydrolysis degree of 10%. The enzyme affinity (Km) was best at temperatures near the optimal temperature for the hydrolysates. Dried hydrolysates had protein values which ranged between 66.3% and 66.9% and a nitrogen solubility in water, of approximately 85%. Hydrolysis yields referred to the concentrate dried mass were 42% for the atomized hydrolysate, and 56% for the freeze-dried one. In conclusion, the enzymatic hydrolysis process improved the nitrogen solubility in water of the sesame proteins.     

响应面法优化鹿血肽的制备工艺

采用碱性蛋白酶水解鹿血蛋白制备鹿血肽.应用响应面分析法选取温度、时间、pH值、酶量4个主要因素,以水解率为响应值,对其工艺进行了优化.得出了鹿血蛋白水解的最佳工艺条件为:温度(53％)、时间(5.5h)、pH(9.5)、酶量(1272U·g-1),在此条件下鹿血的实际水解率为22.13％.实验证明响应面法对鹿血肽的制备...     

Angiotensin-I Converting Enzyme (ACE) Inhibitory and Anti-Oxidant Activities of Sea Cucumber (Actinopyga lecanora) Hydrolysates

In recent years, food protein-derived hydrolysates have received considerable attention because of their numerous health benefits. Amongst the hydrolysates, those with anti-hypertensive and anti-oxidative activities are receiving special attention as both activities can play significant roles in preventing cardiovascular diseases. The present study investigated the angiotensin-I converting enzyme (ACE) inhibitory and anti-oxidative activities of Actinopyga lecanora (A. lecanora) hydrolysates, which had been prepared by alcalase, papain, bromelain, flavourzyme, pepsin, and trypsin under their optimum conditions. The alcalase hydrolysate showed the highest ACE inhibitory activity (69.8%) after 8 h of hydrolysis while the highest anti-oxidative activities measured by 2,2-diphenyl 1-1-picrylhydrazyl radical scavenging (DPPH) (56.00%) and ferrous ion-chelating (FIC) (59.00%) methods were exhibited after 24 h and 8 h of hydrolysis, respectively. The ACE-inhibitory and anti-oxidative activities displayed dose-dependent trends, and increased with increasing protein hydrolysate concentrations. Moreover, strong positive correlations between angiotensin-I converting enzyme (ACE) inhibitory and anti-oxidative activities were also observed. This study indicates that A. lecanora hydrolysate can be exploited as a source of functional food owing to its anti-oxidant as well as anti-hypertension functions.     

Analyzing molecular weight distribution of whey protein hydrolysates

Process parameters on enzymatic hydrolysis and molecular weight (MW) distribution of whey protein hydrolysates were investigated. Whey protein hydrolysates were first gained by the alkaline protease alcalase for 7 h at temperature (50 °C), pH (8.0) and E/S (3%). The diversification of the hydrolysis degree and dissociative amino acid content was investigated during the whey hydrolysis. The dissociative amino acid content was 56.09 μmol/mL with the hydrolysis degree of 20.04%. The results of Sephadex G25 washing and high performance liquid chromatography–electrospray ionization–mass spectrometry (HPLC–ESI–MS) indicated the molecular weight distribution of whey protein hydrolysates ranged from 300 to 1400 Da, and most of whey peptide was under 1000 Da.     

钒铅锌矿硫酸浸出提取钒锌

钒铅锌矿含有多种有价金属,V品位高,具有较高的经济价值。本工作采用硫酸浸出法从该矿中提取钒锌,对浸出过程热力学进行分析,通过条件实验研究硫酸浓度、液固比、浸出时间、搅拌速率、浸出温度等条件对钒、铅、锌等主要有价金属浸出率的影响。结果表明,在较高pH值及较高温度下,浸出液中V会出现水解,含V的水解产物留在浸出渣中影响V浸出率。得到最优浸出条件为：硫酸浓度200 g/L,液固比3:1,浸出时间30 min,搅拌速率200 r/min,浸出温度为30℃。最优条件下V浸出率可达97.90%,Zn浸出率为97.11%,Fe浸出率<1%,Pb浸出率<0.01%。动力学分析结果表明,浸出过程的反应速率受扩散过程控制。酸浸过程使V和Zn进入浸出液,Pb和Fe留在浸出渣中,所得浸出液可使用离子交换或萃取法分离V和Zn。浸出渣中含钒0.41wt%、锌0.61wt%、铁15.50wt%、铅47.70wt%,主要成分为PbSO₄和FeO(OH),可返回火法炼铅系统。     

Continuous enzyme-catalyzed production of 6-aminopenicillanic acid and product concentration by reverse osmosis

The efficiency of 6-aminopenicillanic acid (6-APA) production by enzyme-catalyzed hydrolysis of penicillin G using penicillin G amidase (E. C. 3.5.1.11) immobilized in polyacrylamide gel can be improved by using a lower substrate concentration and an optimized low buffer concentration. In a continuous process the combination of a stirred-tank reactor and a plug-flow reactor gives optimum productivity. Since precipitation of 6-APA is the crucial step in downstream processing, the product concentration has to be as high as possible. This can be achieved by concentrating the product solution by reverse osmosis.     

Parameter optimization for the enzymatic hydrolysis of sunflower oil in high-pressure reactors

This study is concerned with the hydrolysis of sunflower oil in the presence of lipase preparation Lipolase 100T (Aspergillus niger lipase). Supercritical carbon dioxide was used as a solvent for this reaction. In a high-pressure stirred tank reactor operated in a batch mode, the effects of various process parameters (temperature, pressure, enzyme/substrate ratio, pH, and oil/buffer ratio) were investigated to determine the optimal reaction rate and conversion for the hydrolysis process. The optimal concentration of lipase was 0.0714 g/mL of CO₂-free reaction mixture, and the highest conversions of oleic acid (0.193 g/g of oil phase) and linoleic acid (0.586 g/g of oil phase) were obtained at 50°C, 200 bar, pH=7, and an oil/buffer ratio of 1∶1 (w/w).     

Enzymatic modification of sesame seed protein,sourced from waste resource for nutraceutical application

The functional characteristics which include protein solubility at different pH, emulsifying and foaming properties, degree of hydrolysis, molecular weight distribution, antioxidant and ACE inhibitory activity of sesame protein hydrolysates prepared with pepsin, papain and alcalase enzymes were evaluated. The rate of degree of hydrolysis was found to reach maximum (25–30%) within the first time fragment i.e 10 min but 80% of hydrolysis was obtained in 120 min with alcalase. SDS-PAGE of hydrolysates with papain, pepsin and alcalase evinced bands of low molecular weight protein of 14.3 kDa and even lower for alcalase treatment of 120 min. Hydrolysates so formed were of improved functional properties as evident from emulsifying and foaming property. Hydrolysis with different proteases enhanced the protein solubility significantly at pH 7.0. Antioxidative assay revealed radical scavenging activity of the hydrolysates with papain hydrolysates showing maximum antioxidative efficacy. The ultra-filtered peptide fractions which showed comparable ACE inhibitory activity were sequenced by MALDI-TOF and matched to that of previously identified ACE inhibitory peptides. The results corroborate the ACE inhibitory effect of the peptides. Hence, these highly bioactive protein hydrolysates produced from waste sesame meals can be successfully employed in various functional food formulations.