诱变米曲霉发酵高温豆粕菌种筛选及发酵工艺优化

以高温豆粕为原料,以酶活力为指标,通过紫外诱变和遗传稳定性试验选育出遗传性能稳定的蛋白酶高产的米曲霉诱变菌株;以水解度为指标,优化发酵工艺条件,进一步提高高温豆粕的水解度。紫外诱变条件为20W紫外灯35cm处辐照180s,得出最佳的发酵培养基组成为葡萄糖3%和高温豆粕12%;采用单因素试验方法确定的培养条件为:发酵温度30℃、发酵时间48h、接种量9%、摇床速度160r/min和起始pH值5.5,此条件下高温豆粕的水解度可达到24.05%,比优化前提高了3.86%。     

米曲霉固体发酵核桃粕条件优化

核桃粕中的蛋白质是一种优质植物蛋白,其含量高达51.36%,对其进行加工利用,将有力地促进核桃产业的发展。该文利用米曲霉固态发酵核桃粕,以蛋白酶活力为评价指标,通过试验分别探讨发酵温度、发酵时间、米曲霉添加量对核桃粕中蛋白酶活力的影响。在单因素试验的基础上进行L9（34）正交试验,对产酶条件进行优化。结果显示,发酵温度、米曲霉添加量、发酵时间对核桃粕中蛋白酶活力的大小均有极显著影响。获得最佳产酶条件为发酵温度31℃、米曲霉添加量0.015%、发酵时间50 h,此时蛋白酶活力为1 187.20 U/g。并在此条件下,对米曲霉在核桃粕和豆粕中的蛋白酶活力进行比较,发现米曲霉更适宜在核桃粕中发酵产蛋白酶。     

Microbial Changes in Fermented Peanut and Soybean Pastes Containing Kojis Prepared using Aspergillus oryzae and Rhizopus oligosporus

Microbiological profiles of peanut and soybean misos containing 6 and 12% NaCl and kojis prepared with Aspergillus oryzae and Rhizopus oligosporus were monitored over a 90-day period of fermentation. Although total plate counts in misos containing R. oligosporus koji fluctuated while counts in misos containing A. oryzae koji remained constant during the fermentation period, the final microbial populations in sixteen test formulae were similar to the initial counts. Mold populations in mists containing two types of kojis declined similarly during fermentation. There was little difference in populations of Saccharomyces rouxii in misos containing the two types of mold kojis during the first month of fermentation; however, higher numbers of S. rouxii were noted in mitis containing R. oligosporus koji compared to those containing A. oryzae koji during later stages of fermentation. The final pH values of misos were similar, even though misos containing A. oryzae koji had a larger magnitude of drop in pH than did misos containing R. oligosporus koji over the 90-day test period.     

浓醪发酵玉米蛋白粉饲料生产工艺的研究

利用纳豆杆菌采用浓醪发酵法对玉米蛋白进行改性.通过对浓醪发酵条件的优化研究,确定适宜的改善玉米蛋白溶解性的发酵条件,提高玉米蛋白的溶解性,有利于动物对蛋白的消化吸收,从而提高玉米蛋白作为饲料的利用率.适宜的发酵条件为:培养基干基与水的比例为1:3.5,培养基初始pH值为7.0,接种量4.29%,培养温度32℃,摇瓶转速190 r/min,培养时间20 h.在此条件下,培养液中可溶性蛋白质含量可达到(29.05±0.67)mg/ml.     

两株高效降解玉米蛋白粉益生菌的发酵特性研究

通过固体筛培法从豆酱样品筛选到两株高效降解玉米蛋白粉的菌株Bacillus subtilisHDJ1和Bacillus velezensisHDJ2.单因素发酵实验表明,菌株HDJ1液态发酵玉米蛋白粉的最佳条件为:发酵温度40℃,pH 8,接种量6％,底物浓度8％,转速200 r/min,加液体积40 mL,发酵时间7...     

Physical and Chemical Changes in Fermented Peanut and Soybean Pastes Containing Kojis Prepared Using Aspergillus oryzae and Rhizopus oligosporus

Studies were made to determine and compare physical and chemical changes occurring during 90 days of fermentation of miso-like products containing peanuts and soybeans as well as a combination of these oilseeds. Two koji molds (Aspergillus oryzae and Rhizopus oligosporus) and two levels of NaCl (6 and 12%) were evaluated. The L color values decreased more rapidly in misos containing A. oryzae koji compared to misos containing R. oligosporus koji and changes occurred earlier in low-salt formulae than in high-salt formulae. The type of mold koji had no apparent effect on changes in viscosity. The free fatty acid content of misos increased dramatically during the first 4 days of fermentation. Misos containing A. oryzae koji had higher soluble nitrogen and free amino acid content in the final product than did those containing R. oligosporus kojis. Peanut miso products had higher soluble nitrogen contents than did respective soybean products; however, the type of oilseed had little effect on accumulation of free amino acids.     

Extrusion Processing of Wet Corn Gluten Meal

Wet corn gluten meal (WCGM) is that which has not undergone the typical industrial flash drying process. The pH of WCGM was adjusted to 7.0. The samples were then frozen and the water removed by lyophilization. The moisture content of the freeze-dried samples was adjusted to 14, 20, and 26% dry basis and extruded at barrel temperatures of 120, 145, and 170°C with screw speeds of 100, 150, and 200 rpm. Changes in digestibility and water-holding capacity were measured, and the results were compared to similarly processed dry corn gluten meal (DCGM) at pH 7.0.     

Actinomucor elegans、Aspegillus oryzae和Rhizopus oligosporus产蛋白酶条件及蛋白酶性质的比较

比较了腐乳生产菌株Actinomucor elegans、豆酱和酱油生产菌株Aspegillus oryzae以及天培生产菌株Rhizopus oligosporus产生蛋白酶的条件和所产蛋白酶的性质。结果表明,不同的菌株产酶条件及蛋白酶的性质有较大的差异:少孢根霉主要产生酸性蛋白酶,在pH2.5-4.0的酸性介质中、32℃条件下培养时产酶能力较强,所分泌的蛋白酶系在pH5.0时酶活力最高,在pH5.0附近最稳定;米曲霉可以产生酸性、中性及碱性蛋白酶,所产生的蛋白酶活力显著高于少孢根霉和毛霉,米曲霉在酸性条件下产酸性蛋白酶能力强,在中性条件下产中性蛋白酶能力强,在碱性条件下产碱性蛋白酶能力强,在28-32℃时产酶能力强,所分泌的蛋白酶系在pH5.0-9.0的广泛范围内有很强的活力,在pH6.0-8.0的范围内稳定性强;毛霉可以产生酸性、中性及碱性蛋白酶,但酶活力明显低于米曲霉,毛霉在中性偏酸性(pH5.5)的介质中产酸性蛋白酶的能力较强,但介质的酸碱度对毛霉产中性及碱性蛋白酶没有影响,在28℃时产酸性、中性和碱性蛋白酶的能力都比较强,毛霉所分泌的蛋白酶系在pH5.0-9.0的广泛pH范围内有活力,在pH5.0-6.0时酶活力最高,在pH5.0-7.0时稳定强。     

响应面法玉米蛋白粉纯化条件优化

利用超声波辅助法对玉米蛋白粉进行脱色处理,通过响应面分析法优化脱色条件,得到脱色的最佳条件是:超声时间20min,超声温度25℃,料液比1︰20,pH4。酶解、抽滤脱除淀粉效果显著。     

生物降解材料——玉米醇溶蛋白提取工艺的优化研究

玉米醇溶蛋白膜是一种绿色包装,它具有良好的阻气性、阻油性、保香性、防湿性和防紫外线性.可食性及生物降解薄膜或包装材料的制造能增加它的商业价值,使其在食品、化工、医药和生物降解包装材料等方面有着诱人的应用前景.本研究从玉米蛋白粉中提取醇溶蛋白,并建立了玉米醇溶蛋白提取量的快速检测方法,在单因素的基础上采用中心组合设计方法,确定了玉米醇溶蛋白的最佳提取工艺条件:乙醇浓度80%,提取温度57.9℃,液料比(ml/g)9.25.浸提时间122min.     

玉米蛋白粉中叶黄素的提取和纯化

为提高玉米蛋白粉的应用价值,对玉米蛋白粉中叶黄素碱性蛋白酶辅助提取工艺及叶黄素和玉米黄质的分离方法进行研究。分析酶解pH 值、温度、酶添加量、底物质量浓度和酶解时间对总叶黄素得率的影响。结果表明,相比于常规溶剂提取,酶解辅助的方法显著提高了叶黄素的得率(P ＜ 0.05),考虑到提取效率、成本和可行性,得到的最佳工艺参数为pH7.0、酶解温度40℃、酶添加量4000U/g、底物质量浓度110g/L、酶解时间2h。在最佳工艺参数下,总叶黄素的得率为59.57μg/g。采用V(正己烷):V(乙酸乙酯):V(乙醇):V(水)=4:1:4:1 的两相体系将所得的粗提物进行制备型高速逆流色谱的分离纯化,利用高效液相色谱检测得到的反式叶黄素和反式玉米黄质的纯度分别为90.85% 和91.21%。实验证明制备型高速逆流色谱可以成功地将玉米黄粉中叶黄素和玉米黄质分离,但不能彻底分离叶黄素和玉米黄质与其各自的顺式异构体。     

玉米蛋白粉水解产物的分离及其抗氧化活性

以碱性蛋白酶做催化剂水解玉米蛋白粉,水解产物精制后,采用SephedaxG-15和G-10葡聚糖凝胶层析法及高效液相层析法进行分离纯化。以α-生育酚为阳性对照,研究水解产物及其分离组分对DPPH自由基的清除活性和对亚油酸自氧化的抑制作用,同时测定它们的还原力。采用邻苯三酚自氧化法研究它们对超氧阴离子自由基的清除作用。结果表明,抗氧化活性最高的组分是经SephedaxG-10层析法分离得到的组分Ⅱ。组分Ⅱ的分子量分布范围在400～700D之间,富含谷氨酸、丙氨酸、亮氨酸、组氨酸、脯氨酸和苯丙氨酸。     

酶解玉米蛋白粉制备玉米肽

研究碱性蛋白酶和木瓜蛋白酶对玉米蛋白粉的水解效果,以及2种酶分步水解效果.结果表明,碱性蛋白酶的水解效果比木瓜蛋白酶提高7.72%,而双酶分步水解又比碱性蛋白酶水解效果提高20.15%.可得双酶分步水解比单酶水解的效果好.     

米根霉产糖化酶发酵条件的研究

以R.SCLG 0319菌株的糖化酶催化活性为指标,研究了发酵时间、温度、装液量、初始pH值及相关金属离子等因素对该菌株发酵产糖化酶活力的影响.结果表明,R.SCLG 0319菌株摇瓶发酵产糖化酶40h为宜,最适发酵温度30℃,装液量100mL/250mL,培养基初始pH值6.0;菌株对低浓度乙醇作用呈现依赖性,培养基中6%vol酒精度时酶活力达到135 U/mL,可耐12%vol酒精度,在高浓度乙醇作用下酶活力迅速下降;Cu2+、Ca2+ 和Mg2+呈现激活效应,其中Mg2+的效应最明显,酶活力增强50%,Fe2+、Zn2+ 和Mn2+呈现出抑制效应,其中Fe2+的抑制作用最大,酶活力降低近80%.     

中性蛋白酶酶解玉米蛋白工艺条件的优化

通过对酶法水解玉米粉蛋白制备多肽的工艺进行了研究,试验以水解度(DH%)和氮溶解指数X%)为指标确定了最佳酶解工艺条件.结果表明,在pH 7.5,酶解温度50℃,酶与底物比2%,底物浓度5%的条件下酶解4 h,可使水解度和氮溶解指数分别达到23.74%和24.02%.     

米根霉高效利用玉米淀粉生产乳酸的发酵条件优化

研究米根霉HB12利用玉米淀粉生产乳酸的发酵条件优化。从土壤中新筛选得到一株以高浓度玉米淀粉为原料发酵生产乳酸的米根霉HB12。通过单因素及正交试验,得到最佳发酵培养基组成(g/L)为：玉米淀粉140、NH4Cl 2、KH2PO4 0.3、MgSO4·7H2O 0.3、ZnSO4·7H2O 0.05、CaCO3 80;最佳培养条件为：摇瓶装液量50mL/250mL,接种量为2.5×106个孢子,35℃、200r/min培养108h。该条件下,菌株最大产酸量为104.9g/L,产酸速率为0.97g/(L·h),对玉米淀粉的转化率达74.9%,产酸量提高了49.4%。此菌株能够直接高效利用价格低廉来源广泛的玉米淀粉发酵生产乳酸,具有很好的工业应用前景。     

Fermentation of legumes with Rhizopus oligosporus: effect on physicochemical,functional and microstructural properties

The present study investigated the effect of fermentation by Rhizopus oligosporus on the nutritional, functional, colour and microstructural properties of some commonly consumed legumes, that is, chickpea (kabuli and desi), pigeon pea and soybean. Results revealed a substantial (P < 0.05) increment in the protein (5–14%) and ash (5–15%) contents as well as those of essential (13–21%) and non-essential (3–15%) amino acids with fermentation. Fatty acid composition showed the varied concentrations of polyunsaturated, monounsaturated and saturated fatty acids in fermented legumes. Further, fermentation significantly (P < 0.05) modified the functional and colour properties of legumes. The alteration in the structural conformation of legumes upon fermentation was observed with scanning electron microscopy which confirmed the enzymatic action on the proteins, fibres and lipid bodies. The results concluded that fermentation of these legumes could be a potential approach in developing the novel functional foods to address the concerns of food and nutrition securities.     

米根霉直接发酵玉米粉生产L-(+)-乳酸的研究

以米根霉(Rhizopus oryzae)NRRL395为生产菌,玉米粉为发酵基质,对玉米粉与水两相分开灭菌冷却后混合制成玉米粉悬浊液发酵生产L-(+)-乳酸的新工艺进行了研究。试验结果表明,新工艺在不添加任何外源营养的情况下,以150 g/L天然玉米粉为培养基可产L-(+)-乳酸88.8 g/L,L-(+)-乳酸对玉米粉的转化率达到59.2%,对葡萄糖的转化率达到72.4%。该工艺克服了玉米粉在浓度较高情况下由于蒸煮灭菌冷却后呈凝胶而不能被发酵的困难;且省去酶解糖化操作,使成本降低,具有较高的应用价值。     

玉米蛋白粉的应用研究进展

综述了玉米蛋白粉的组成、营养价值及其成分特点,并且阐述了国内利用玉米蛋白粉开发出的提取玉米黄色素、天然β-胡萝卜素、玉米醇溶蛋白、氨基酸,制备玉米活性肽等用途。