发芽燕麦酶解工艺条件的优化

利用燕麦发芽过程中形成的酶系进行燕麦自身的酶解,分别研究了酶解温度、pH和燕麦浓度对发芽燕麦酶解液中蛋白水解度和还原糖含量的影响。试验结果表明,发芽燕麦酶解液中蛋白酶的最适温度为50℃,最适pH为5.0,燕麦浓度为0.20 mg/mL;淀粉酶的最适温度为60℃,最适pH为5.5,燕麦浓度为0.20 mg/mL。在上述酶解条件的基础上,确定发芽燕麦酶解的优化工艺为:0.20 mg/mL的燕麦酶解液在50℃,pH 5.0的条件下酶解3 h后,将酶解温度升至60℃,pH调至5.5,继续酶解至7 h,酶解结束。此时燕麦酶解液中蛋白水解度和还原糖含量都基本达到最高值,分别为12.18%和34.0 mg/mL。     

燕麦蛋白的制备工艺研究

为得到质量良好的纯化燕麦蛋白产品,采用碱酶两步法制备燕麦蛋白,通过正交试验优化工艺条件,利用凯氏定氮法进行蛋白质含量测定.在液料比、温度、pH、提取时间单因素试验的基础上,确立碱提最佳工艺条件为:温度40℃,液料比1:12(V:w),pH 9.6,提取时间30 min,在此条件下,蛋白质提取率46.73%,纯度69.75%.进一步用α-淀粉酶对燕麦蛋白进行纯化,最佳酶解条件为:加酶量60 U/g,pH 6.0,温度50℃,时间30 min,蛋白质提取率58.57%,纯度86.65%.     

酶解制备苦荞蛋白抗氧化肽及其分离纯化研究

以苦荞麦粉为原料,提取苦荞蛋白,分别采用碱性蛋白酶、胃蛋白酶、胰蛋白酶对蛋白进行酶解,采用DPPH法比较不同酶解产物的抗氧化活性,从而筛选水解制备苦荞蛋白抗氧化肽的最适酶。以水解度为指标,利用单因素试验和响应面法优化酶解工艺条件。结果表明,不同蛋白酶酶解产物的抗氧化活性大小为:胃蛋白酶胰蛋白酶碱性蛋白酶,其中胃蛋白酶酶解产物的DPPH自由基清除率最高,为68.47%。胃蛋白酶最佳水解工艺条件为:时间2.5 h、温度38℃、pH 2.0,在此条件下苦荞蛋白水解度为32.68%。采用超滤对苦荞蛋白水解物进行分离纯化,结果表明,分子量3 kDa的水解物具有显著的抗氧化活性;经凝胶过滤色谱进一步分离得到3个峰,小分子量峰组分显示出最强的抗氧化活性。     

碱法和超声辅助酶法分离燕麦淀粉的比较研究

比较碱法和超声辅助酶法两种不同的分离方法对燕麦淀粉的提取效果影响.结果表明,碱法最佳工艺条件为pH值为10、料液比1∶6(m∶V)、搅拌时间为90min,该条件下燕麦淀粉的提取率为85.62％.超声辅助酶法分离燕麦淀粉的最佳工艺条件为:酶添加量为1.0％、酶解温度为40℃、酶解时间1h,超声处理20min,酶解pH值为7.0,该务件下燕麦淀粉的提取率为88.91％.试验结果显示超声辅助酶法提取率高,反应时间短,节约能耗,环境污染少.     

碱性蛋白酶水解脱除蛋白的橡子淀粉分离工艺条件优化

为优化碱性蛋白酶水解蛋白的橡子淀粉提取工艺条件,选择酶解时间、温度、pH值、酶用量等因素进行单因素试验和正交试验,确定了适宜的橡子淀粉提取工艺条件。结果表明,碱性蛋白酶水解去除蛋白的pH值和酶解温度对橡子淀粉中总淀粉含量的影响较大,影响程度依次为pH值〉酶解温度〉酶解时间〉酶用量;碱性蛋白酶水解去除蛋白的适宜工艺条件为pH值为11、酶解温度为45℃、酶解时间为140 min、酶用量为600 U/g。结合1%双氧水漂白处理12 h后,橡子淀粉中的蛋白未检出。     

响应面试验优化中性蛋白酶辅助提取青稞淀粉工艺

采用中性蛋白酶辅助提取青稞淀粉,研究料液比、加酶量、酶解时间、酶解温度和pH值对青稞淀粉中蛋白残留量的影响,选择加酶量、酶解时间、酶解温度为影响因素进行响应面优化试验。以淀粉蛋白残留量和淀粉提取率为评价指标,确定最佳提取工艺条件。结果表明,加酶量、酶解温度、酶解时间、加酶量与酶解温度的交互作用及加酶量与酶解时间的交互作用对淀粉蛋白残留量有极显著影响,而对淀粉提取率无显著影响。实验范围内得到的最佳提取工艺条件为加酶量140.79 U/g、酶解温度45.01 ℃、酶解时间2.57 h,在此条件下青稞淀粉的提取率为60.36%,淀粉蛋白残留量为1.31%。     

辣椒粕分离蛋白酶解工艺条件的优化

从辣椒粕中提取粗蛋白,建立蛋白酶水解辣椒粕分离蛋白制备呈味肽的最佳条件。以水解度和肽得率为指标,对胰蛋白酶、木瓜蛋白酶、碱性蛋白酶、复合蛋白酶4种酶水解辣椒粕分离蛋白的效果进行比较研究。结果表明:复合蛋白酶的水解效果最佳。通过单因素试验选取复合蛋白酶作用的固液比、酶用量、酶解时间、酶解pH值及酶解温度作为试验因素,初步确立复合蛋白酶的水解条件。并通过正交试验优化最终确定复合蛋白酶水解辣椒粕分离蛋白的最佳工艺条件为固液比110(mV),酶用量2.0%,酶解时间4h,酶解pH值6.5,酶解温度50℃。通过实验验证,在该条件下,复合蛋白酶对辣椒粕分离蛋白具有较好的水解效果,其水解度为19.60%,肽得率为6.30%。     

酸性蛋白酶提取白酒丢糟中淀粉条件优化研究

为了提高丢糟中淀粉的利用率,采用酸性蛋白酶处理浓香型白酒丢糟,使与淀粉紧密结合的蛋白质得以分解,丢糟中的部分淀粉被释放后与淀粉酶直接接触被酶解,转化为可被微生物生长利用的多糖类物质。以淀粉和蛋白提取率为评价指标,考察酶解温度、酶解时间、酶解pH值、酶添加量对蛋白和淀粉提取率的影响,采用单因素及正交试验优化淀粉提取条件。结果表明,各因素对淀粉提取率结果影响顺序为：酶解温度＞酶解pH＞酶解时间＞酶添加量,最佳淀粉提取条件为酶解温度75 ℃,酶解时间120 min,酶解pH为4.0,酶添加量0.02 mL/g。在此最佳条件下,淀粉提取率为24.26%,蛋白提取率为12.21%。     

榛子蛋白提取及纯化的工艺优化

摘要：以榛子粕为原料,采用碱性蛋白酶酶解辅助碱溶酸沉法提取榛子蛋白,然后加入碱液复溶、碱性蛋白酶酶解、酸沉纯化。在单因素试验的基础上采用响应面法对提取过程中酶解工艺条件进行优化,采用正交试验优化榛子蛋白纯化工艺。结果表明：最优酶解工艺条件为酶解温度46 ℃、pH 8、酶解时间3.7 h,在此条件下榛子蛋白提取率达到53.16%;最佳纯化条件为反应温度50 ℃、液料比5∶ 1、复溶pH 11,在此条件下榛子蛋白纯度为95.23%。     

Flavourzyme蛋白酶酶解绿豆分离蛋白制备低聚肽的工艺研究

本文选用Flavourzyme蛋白酶对绿豆分离蛋白进行酶法水解以制备低聚肽。在单因素考察的基础上,采用四因素、三水平的正交试验设计优化酶解条件。得到最适的工艺条件为:温度60℃、pH7.0、底物浓度9%、酶浓度6000U/g,水解时间180min。在此条件下,绿豆分离蛋白水解度的平均值可达22.77%。     

Processing and composition of wild oat groats (Avena fatua L.)

Wild oats, a common weed contaminant in commercial grain, were investigated as a potential food grain since large quantities are recovered in cleaning plants. Pure wild oats were separated effectively from mixed feed oat samples using thickness graders in combination with indent separators. The hulls were removed by impact hullers and air aspiration to yield an attractive groat which could be further processed into oat flakes or milled into flour and bran components.The wild groat contained over 20% protein, 8% lipid and 55% starch, and was rich in essential minerals and vitamins. The yield of flour to bran was 60:40 and their respective protein contents were about 16% and 25%. Since the wild oat proteins, like those in the common groat, contain nearly 4% of lysine and nutritionally adequate levels of other essential amino acids, the wild groat appears to be an excellent alternative source of dietary protein. Specific applications would be as a protein and energy constitutent in infant foods, breakfast cereals and low-allergenic diets, and as a source of oat bran for cardiac patients.     

Oat Gum and β-Glucan Extraction from Oat Bran and Rolled Oats: Temperature and pH Effects

The extractability of oat gum from oat bran and rolled oats was studied using 12 treatment combinations in a factorial design (2x3x4x2) i.e. 2 oat products; 3 pH (8.0–10.5); 4 temperatures (5O–70°C); 2 replications. The extraction procedure involved: (a) alkaline treatment of flour and removal of starch residue; (b) isoelectric precipitation of protein residue [namely, protein concentrates (PC)]; (c) and alcohol precipitation of oat gum/β-glucan and collection of gum by centrifu-gation. Extracted oat gum ranged from 2.99–6.28% for oat bran and 1.82–5.24% for rollcd oats whereas β-glucan (in gum) ranged from 70–89% and 50–68%, respectively. Protein contents of the PC from oat bran was 69–91% and rolled oats 66–89%. Correspondingly, starch content of residues ranged from 30–63% and 61–47%. Oat gum/β-glucan extracted at pH 9.2/50°C or pH 10.5/50/55°C showed little or no starch contamination.     

燕麦粉脂质和蛋白质组分对抗性淀粉形成的影响

为明确原料组分对抗性淀粉形成的影响,以燕麦粉为原料,对其脂质和蛋白组分分别进行单一成分分离和层级分离,利用分离组分后的样品为原料制备抗性淀粉,分析并探讨了燕麦粉中脂质、清蛋白、球蛋白、醇溶蛋白、谷蛋白和残渣蛋白等组分对抗性淀粉形成的影响。研究结果表明:燕麦粉中脂质或醇溶蛋白的存在抑制抗性淀粉的形成,能显著降低抗性淀粉得率;清蛋白、球蛋白或残渣蛋白对抗性淀粉的形成均具有促进作用。在制备燕麦抗性淀粉相关制品时,可考虑对原料的成分进行适当脱除或重组以提高抗性淀粉得率。     

Effects of cross-linking and acetylation on oat starch properties

Starch samples separated from oat were modified with two different levels of POCl₃ (0.5 and 1.0 g kg⁻¹) as a cross-linking agent and two different levels of acetic anhydride (6% and 8% (w/w)) for acetylation. Swelling factor, thermal properties and retrogradation measurements were evaluated to characterise the influence of phosphorylation and acetylation on oat starch. Cross-linking decreased the swelling factor and did not improve gelatinization temperature while it increased synaeresis in comparison with native starch. Acetylation increased swelling factor but reduced gelatinization temperature and synaeresis of oat starch.     

酶解燕麦蛋白制备ACE抑制肽的研究

本研究以燕麦蛋白为原料,分别选用Alcalase、Neutrase 和Protamex 进行单独或联合水解,经活性炭YD-303脱色、大孔吸附树脂DA-201C Ⅱ脱盐及分级纯化、Sephadex G-25 凝胶色谱柱进一步分离,以获得高纯度、高活性的血管紧张素转化酶(angiotensin converting enzyme,ACE)抑制肽。结果表明：单酶反应时,Alcalase 水解2h所获得的产物对ACE 的抑制率可达85.40%;YD-303 处理燕麦蛋白酶解液脱色最优工艺为添加量1.5%(W/V)、pH3.5、温度40℃、脱色时间75min。利用75% 乙醇洗脱大孔吸附树脂DA-201C Ⅱ所获得的组分ACE 抑制活性最高,其经Sephadex G-25 进一步分离纯化,得到四个分离组分,第四组分的ACE 抑制活性最高,抑制率为95.6%。     

高纯度大米蛋白和淀粉的分离提取

高纯度的大米蛋白和大米淀粉可以作为大米综合利用的两个主产品，本研究采用碱法将大米蛋白和淀粉分离，研究表明最适提取条件是：NaOH求度0．05N，提取2h此条件下分离体系不受破坏，且大米蛋白的蛋白含量可达94.03％(干基)，蛋白得率63．37％；大米淀粉中蛋白含量0．39％(干基)，淀粉得率47．87%。     

Solubility Pattern and Recrystallization Behavior of Oat Starch

The oat starch studied had a lipid content of 1,3% and amylose content of 29%. Based on the colorimetric assay, only 15% of the starch leached out from the native granules at 95°C was amylose, whereas 85% of the starch leached from the defatted granules was amylose. The solubilized amylopectin-type material of native oat starch was of clearly lower molecular weight than most of the amylopectin in the original starch. The amylopectin recrystallization enthalpy of 50% native oat starch dispersion Id after gelatinization was 2J/g and that of defatted oat starch was 4J/g.     

酶解改性对燕麦粉中淀粉含量及消化性的影响

为研究酶解对燕麦粉的淀粉含量和消化性的影响,本文采用双波长法测定天然燕麦粉、焙烤燕麦粉、酶解燕麦粉中直链淀粉、支链淀粉及总淀粉含量,并测定其快速消化淀粉、慢速消化淀粉和抗性淀粉含量以评价其消化性,利用红外光谱仪及电镜对其结构和颗粒形貌进行分析。结果表明,与天然燕麦粉相比,焙烤燕麦粉中直链淀粉、支链淀粉及总淀粉含量没有显著变化(p>0.05),但酶解改性燕麦粉变化极显著(p<0.01),分别下降了77.97%、43.55%、46.19%;焙烤燕麦粉中快速消化淀粉、慢速消化淀粉和抗性淀粉含量没有显著变化(p>0.05),但酶解改性燕麦粉变化极显著(p<0.01),分别下降了82.29%、57.06%、33.48%;经淀粉的红外光谱及1047/1022、1022/995 cm^-1特征吸收比值没有显著变化(p>0.05)。经焙烤和酶解改性的燕麦粉中大淀粉颗粒表面出现较多的凹陷,而酶解改性后的淀粉中含有的小颗粒较少,且表面的凹陷程度不同。酶解改性极显著降低了燕麦粉的直链淀粉、支链淀粉、总淀粉、快速消化淀粉、慢速消化淀粉及抗性淀粉含量(p<0.01),会对燕麦粉加工性能及营养价值产生影响。     

Laboratory‐scale Dry/Wet‐Milling Process for the Extraction of Starch and Gluten from Wheat

A laboratory‐scale process is presented for the manufacture of starch and gluten from wheat. Main feature of this process is that whole wheat kernels are crushed dry between smooth rolls prior to wet disintegration in excess water in such way that gluten formation is prevented and fibres can be removed by sieving. Centrifugation of the endosperm suspension yields a dough which can be separated into starch and gluten using an established batter process. The results suggest that starch recovery is increased in comparison to a conventional wheat flour process without a concomitant decrease in protein recovery. Although starch purification was omitted, a total starch with a low protein content is obtained. On the other hand, the protein content of the gluten fraction is rather low due to difficulties in removing the starch. Despite this, the effect on dough mechanical properties by the addition of gluten obtained from wet‐milled wheat is comparable to the effect of gluten from flour.     

The effects of steaming and roasting treatments on β‐glucan,lipid and starch in the kernels of naked oat (Avena nuda)

BACKGROUND: Normal pressure steaming (NPS), autoclaved steaming (AS), and hot‐air roasting (HAR) are widely used to deactivate oat enzyme in the oat‐processing industry. Infrared roasting (IR) is a new oat deactivation method, and is welcomed and employed by increasing numbers of oat‐processing plants in China. It is widely known that oat starch plays an important role in the processing function of oat food, and that oat β‐glucan and lipid contribute greatly to the health benefits of oat food. However, the effects of steaming and roasting treatments on the starch, β‐glucan and lipid in oat kernels are poorly known. RESULTS: In this research, the level and distribution of β‐glucan and lipid in oat kernels with and without deactivation treatments were tested. We also measured the viscosity properties of oat flour from kernels after NPS, AS, HAR and IR treatments, and examined the effects of these treatments on oat starch granularity using scanning electron microscopy. The results showed that the deactivation treatments did not have significant effects on oat β‐glucan and lipid levels in oat kernels (P < 0.01). The distribution of β‐glucan and lipid in enzyme‐deactivated kernels was very similar to that in normal kernels. NPS, AS, HAR and IR treatments changed the shape of starch granules, crumbled large starch granules, reduced the connection between the protein network and starch granules, and improved starch gelatinization properties. CONCLUSIONS: NPS, AS, HAR and IR treatments can change the structure of oat starch granules and improve the viscosity property of oat starch without causing β‐glucan and lipid loss to oat food. Copyright © 2010 Society of Chemical Industry