黑曲霉植酸酶对豆粕中植酸的脱磷作用

单胃动物不能有效利用植物性饲料中的磷,因为磷主要以植酸磷的形式存在。通常通过在饲料中添加植酸酶,水解植酸脱磷,来提高动物对磷的利用率。利用黑曲霉发酵产生的植酸酶粗酶液对豆粕中的植酸进行脱磷作用研究。通过单因素试验和正交试验确定植酸酶水解豆粕中植酸的最适条件为:酶加量为600 U/g,底物浓度为60 mg/m L,p H为4,温度为55℃,脱去无机磷的量为4.127 mg/g。最优条件下,豆粕中植酸水解5 h后的水解率为87.34%。     

酶法提取麸皮中膳食纤维的研究

通过耐高温α-淀粉酶和蛋白酶对麸皮中的淀粉和蛋白质进行水解,提取麸皮中的膳食纤维。通过正交试验设计,确定α-淀粉酶去除麸皮淀粉的反应条件为：酶用量为3％（[E],[S]）,90℃,水解2h;选择水解蛋白质能力较强的碱性蛋白酶对麸皮进行水解以除去其中的蛋白质,碱性蛋白酶降解蛋白质的优化条件为：蛋白酶用量1．4％（[E],[S]）、60℃、水解1．5h。在上述优化工艺条件下,麸皮中膳食纤维的提取率达到77．6％。     

双酶酶解制备黑小麦麸皮抗氧化肽

采用双酶法分步酶解黑小麦麸皮蛋白制备抗氧化肽,以水解度、肽得率及总抗氧化活性为指标,通过单因素试验及正交法优化其最佳工艺条件。第一步采用碱性蛋白酶酶解的最佳条件为pH 9,时间2 h,温度50℃,酶添加量18000 U/g;黑小麦麸皮蛋白水解度为11.46%,肽得率为38.33%,总抗氧化活性为6.65μmol/g。第二步采用风味酶酶解的最佳条件为pH 6,温度50℃,时间2 h,酶活添加量10000 U/g;此时水解度为22.74%,肽得率为52.36%,总抗氧化活性为8.47μmol/g。     

响应面法优化麦麸发酵产植酸酶条件的研究

以纳豆芽孢杆菌JSU-2为供试菌株,麦麸皮为唯一固体发酵基质,运用响应面法对其产植酸酶的条件进行优化.首先用24-1部分因子试验设计对影响植酸酶活性的主要变量进行了评价,发现主要影响因子为麸皮与水的比例和培养时间.然后用中心组合试验设计确定主要变量的最佳水平.最佳产酶发酵条件为:粒径为3 mm、麸皮与水的比例为1:9.6、接种量为3 mL和培养时间为25 h.在最佳产酶条件下进行发酵,得到的植酸酶活性为595 U/g麦麸.     

小麦麸皮蛋白的酶法提取工艺及性能研究

以小麦麸皮为原料,利用中性蛋白酶进行小麦麸皮蛋白的提取.研究了温度、pH值、固液比、酶解时间和酶用量对小麦麸皮蛋白提取率的影响.通过正交试验确定酶水解的最佳工艺参数,并测定了小麦麸皮蛋白的性能.结果表明,小麦麸皮酶法水解提取麸皮蛋白最佳工艺条件为:温度50℃,pH 6.8,酶用量[E]/[S]=O.8%,固液比1:10.酶解时间2.5 h,在此条件下蛋白平均提取率为37.01%.利用中性蛋白酶酶法水解得到的小麦麸皮蛋白具有较好的乳化性能.     

用小麦麸皮植酸酶制备三磷酸肌醇的研究

本文重点研究了从麸皮中提取植酸酶,并对其酶学性质进行了研究,其最佳酶活条件为pH5.15,温度为37℃。采用麸皮植酸酶部分水解植酸后,利用离子交换树脂分离得到了三磷酸肌醇。此法为磷酸肌醇的酶法制取提供了可行性方案。     

麸皮中植酸酶的研究

经研究采用最优的提取工艺，1kg麸皮可以得到活力为2.7×106u／g的粉末状植酸酶7g，分别在不同的温度和pH值条件下测定此植酸酶的活力，得到它的最适温度和pH值分别为55℃和5.2，米氏常数为3.3×10(-4)mol／l。用此麸皮植酸酶催化水解米糠植酸盐，植酸磷的水解率高达99.95％。     

小龙虾虾壳蛋白酶解条件的研究

文章主要介绍了以单酶、双酶协同分步酶解虾壳、虾头,以脱蛋白率(PR,%)为试验的衡量指标,对pH值、酶解温度、酶解时间、酶加量等试验条件进行考察。结果表明:胃蛋白酶的最优水解条件为pH值3.0,温度40℃,酶加量0.2%,水解时间4h,酶解液中蛋白质含量为4.243mg/mL,脱蛋白率最高达53.9%;碱性蛋白酶的最优水解条件为pH值7.5,温度55℃,酶加量0.3%,水解时间4h,酶解液中蛋白质含量为4.855mg/mL,脱蛋白率最高达61.9%;双酶协同分步酶解最优条件为碱性蛋白酶酶解3h(pH 7.5、温度40℃、酶加量0.3%),胃蛋白酶酶解1h(pH 3.0、温度40℃、酶加量0.2%),脱蛋白率为86.1%,酶解液中蛋白质含量为6.715mg/mL。     

外源性植酸酶在大豆乳中的应用

植物性食物中的植酸不能被单胃动物吸收,但是植酸酶能够水解植酸最终释放出肌醇和无机磷,供单胃动物吸收利用。本实验在研究温度、pH等因素对植酸酶活性影响的基础上,确定植酸酶催化植酸的水解条件为温度45℃、pH4.5、时间2h、酶添加量300FTU/kg。将植酸酶添加到大豆乳中,对大豆乳中植酸/植酸盐进行水解,分析发现大豆乳中有机磷的水解率高达82.9%;植酸酶对大豆乳中植酸/植酸盐的水解作用,对提高大豆乳的营养价值具有重要意义。     

紫小麦麸皮抗氧化肽提取条件优化研究

采用酶法制备紫小麦麸皮抗氧化肽,在单因素实验的基础上,以水解度、肽得率、总抗氧化活性为指标,采用正交法优化紫小麦麸皮抗氧化肽的最佳制备工艺。结果表明:碱性蛋白酶较适宜制备紫小麦麸皮抗氧化肽;最佳提取条件为水解时间2 h、水解温度50℃、pH9、酶添加量14000U/g;在该条件下紫小麦麸皮蛋白的水解度为10.57%,肽得率为51.17%,制备的抗氧化肽的总抗氧化活性为7.98μmol/g。     

微波辐射水解植酸快速制备肌醇的研究

采用微波辐射法水解植酸制备肌醇，缩短了水解时间和获得了较好的产率。用正交实验法确定了制备肌醇的最佳水解条件。提出了分析水解度的方法和探讨了植酸微波水解机理。     

响应面法优化草酸钾溶液提取菜籽饼中植酸工艺

菜籽饼是提取植酸的良好原料,植酸具有独特的生物活性.采用草酸钾溶液提取菜籽饼中的植酸,在单因素试验的基础上,通过响应面法优化植酸提取工艺,建立了以草酸钾溶液提取植酸的二次多项数学模型,并得到最佳工艺条件为:pH 8,液料比14∶1,草酸钾溶液浓度0.075 mol/L,提取时间5h.经过验证试验,在最佳工艺条件下,植酸得率为1.81％.     

Dephosphorylation of Phytic Acid in Rice Bran

Incubation time and temperature, moisture content, and pH were examined to determine the conditions necessary for the hydrolysis of phytic acid in rice bran. The extent of hydrolysis increased with increase in moisture content, and autoclaving for 1 hr at 121°C destroyed a significant proportion of the phytic acid at high moisture contents. Maximum hydrolysis of phytic acid occurred by heating at pH 4.5. Incubation of rice bran slurry for 24 hr at 55°C, pH 5.1 reduced the phytic acid level by approximately 80%.     

菜籽粕分步酶解制备水解产物的研究

以脱脂菜籽粕为原料,水解度为考察指标,采用碱性蛋白酶与中性蛋白酶分步酶解法制备复合氨基酸及小肽等水解产物。通过正交试验确定碱性蛋白酶的最佳酶解工艺参数为：温度50℃、pH10.5、加酶量3250U/g、液料比15:1、时间1.5h;中性蛋白酶的最佳酶解工艺参数为：温度45℃、pH9、加酶量4500U/g、时间2h。制备的复合氨基酸及小肽等水解产物总水解度和氮收率可达25.66% 和86.8%;水解产物在pH3～7 范围内,氮溶解指数高于72.19％。三氯乙酸氮溶解指数达85.67%,且产物中植酸、单宁等主要的抗营养因子的含量明显降低。     

外源酶对糙米中植酸降解的影响

利用外源酶制剂降解糙米中的抗营养因子植酸,以提高糙米营养价值。以植酸降解量为指标,考察pH值、温度、酶作用时间和加酶量对外源植酸酶作用的影响,并考察纤维素酶和果胶酶与植酸酶的协同作用效果。结果显示植酸酶作用的适宜条件为：酶用量0.4U/mL,作用温度50℃,pH5.2,浸泡时间4h;添加纤维素酶和果胶酶能有效促进植酸酶的降解作用,大大提高植酸降解率。外源酶制剂能有效降解糙米中的植酸。     

三氯化铁滴定法测定植酸含量方法的优化及改进研究

以麦麸为材料、采用超声波技术对植酸测定方法中的三氯化铁滴定法进行优化及改进研究。通过单因素和正交试验,得到植酸超声浸提最佳条件,即采用0.8mol/L 稀盐酸溶液、在700W、20～25kHz 超声波处理15min后,50℃水浴浸提1.5h。从而建立一种快速、简便、廉价的三氯化铁滴定法测定植酸含量的方法。与无超声处理比较,该方法大大缩短了浸提时间,由5h 缩短到1.5h,而植酸含量由5.5049% 提高到6.6341%。     

Effect of Soda Leavening on Phytic Acid Content and Physical Characteristics of Middle Eastern Breads

The effect of soda (sodium bicarbonate) as a leavening agent on pH, phytic acid hydrolysis and physical quality of a fermentation model system and two popular Middle Eastern breads, Iranian taftoon and Pakistani naan (Arabic) were studied. Supplementing 0.2 and 0.4% soda invariably decreased phytic acid hydrolysis. In sour starter supplemented dough, phytic acid was reduced by 82% after 3 hr. However, when 0.4% soda and sour starter were added loss of phytic acid did not exceed 29%. Supplementing soda in taftoon and naan bread formula significantly lowered phytic acid hydrolysis during fermentation. Soda had no apparent improvement on physical quality of breads but increased the dough water absorption and lengthened the mixing time.     

Phytic acid concentration in selected raw materials and analysis of its hydrolysis rate with the use of microbial phytases during the mashing process

Phytic acid present in the raw materials can complex with many compounds and therefore limit their availability to the yeast during the alcoholic fermentation process. An effective utilization of biogenic compounds bound in phytates requires a detailed analysis of the raw materials for their phytic acid content. The aim of this study was to characterize the major technological parameters for selected raw materials used in the distilling industry (maize, rye, wheat and triticale grain) and to determine the phytic acid content and the IP6/total phosphorus ratio. The phytic acid hydrolysis rate during the mashing process, with the use of microbial phytases, was analysed. The highest phytic acid concentrations (2.30 ± 0.20 mg/g dry matter) and the highest IP6/total P (80.42 ± 6.99%) were observed in the maize grain samples. Therefore, further studies on the phytic acid hydrolysis rate with the use of various phytases were conducted for the maize grain. The highest hydrolytic activity was observed for the Phytase 10000L preparation. This was the preparation that hydrolysed the phytic acid completely in up to 90 min. The application of a highly effective phytase, in ethanol production from maize grain, could lead to a more effective utilization of the biogenic compounds during the fermentation process. Copyright © 2015 The Institute of Brewing & Distilling     

Fate of phytic acid during bread making

The effect of malt addition and yeast concentration on the hydrolysis of phytic acid during different stages of bread making has been reported. There was a considerable hydrolysis of phytic acid with the addition of yeast and malt. In the breads of S-308 and WL-711 wheat varieties, the loss of phytic phosphorus was 6.6. 8,1; 24.6, 23.0 and 26.6, 27.7% in case of nonyeasted, 1.5% and 3% yeasted dough of whole wheat flour (Atta) respectively. However in white bread, the loss of phytic phosphorus was 14.0 and 18.4; 46.2 and 41.5; 51.7 and 49.4%, in non-yeasted, 1.5% and 3% yeasted doughs of S-308 and WL-711 wheat varieties respectively. A significant loss of phytic acid was observed at a yeast level of 1.5 and 3% and with 0.4% malt addition as compared with the control. Most of the phytic acid was hydrolysed during the fermentation and proofing stages in both types of bread samples.     

In vitro Effects of Phytic Acid and Polyphenols on Starch Digestion and Fiber Degradation

The effect of phytic acid and polyphenols on the rate and extent of starch digestion as well as on fiber degradation was studied in vitro. Addition of phytic acid only had negligible influence on the enzyme activity of the amylases tested. In contrast, enzymes concerned with starch hydrolysis in the digestive channel (α-amylase, amyloglucosidase/maltase) were inhibited by tannic acid, and to some extent also by catechin. Furthermore, tannic acid reduced the total recovery of starch during enzymic starch analysis. The activity of cellulases and hemicellulases was not affected by phytic acid or catechin. However, the degradation of cellulose powder was inhibited by tannic acid, whereas no inhibition could be observed with carboxymethyl-cellulose as substrate.