玉米淀粉实验室提取方法研究

探讨了实验室提取玉米淀粉的工艺条件,通过研究影响提取率和纯度的相关因素,最终确定提取淀粉的最佳工艺：浸泡温度50℃,乳酸和NaHSO3质量分数均为0.5%,浸泡时间36 h,流槽倾斜度为0.015。     

酶法提取枸杞多糖工艺研究

文研究了酶法提取枸杞多糖的最佳工艺条件以及枸杞中多糖的分离方法。采用木瓜蛋白酶处理,对作用温度、加酶量、最适pH值、作用时间进行正交试验。确定了酶法提取枸杞多糖的最佳工艺：加酶量0．3％,酶解反应的pH值为7．0,温度为45℃,反应时间为2h,提取率可达14．9％。     

玉米淀粉实验室提取方法研究

以普通黄马齿玉米为原料,采用湿法提取淀粉工艺,制得淀粉得率高、优质纯净玉米淀粉;通过大量实验设计筛选出最佳提取方案:浸泡温度50℃,乳酸和NaHSO3浓度均为0．5％,浸泡时间36 h,流槽倾斜度为0．015 cm／cm。     

玉米酶法浸泡工艺的优化

玉米酶法浸泡是玉米淀粉生产中一种高效节能的浸泡工艺。以玉米为原料,通过单因素实验和正交实验,考察玉米酶法浸泡的浸泡时间、浸泡温度、加酶量和pH值对玉米浸泡效果的影响。实验结果表明,玉米酶法浸泡的最佳工艺条件为:浸泡时间4.0h、加酶量0.15ml/(100g玉米)、浸泡温度50℃、pH3.0。在该条件下,淀粉提取率提高到84.48%,与传统工艺相当;但成品中淀粉SO2质量分数0.013%,比传统工艺降低了27.78%。     

糖化酶法制备微孔淀粉工艺条件的研究

采用糖化酶对玉米淀粉进行部分降解制备微孔淀粉，通过对淀粉得率、比容积和吸油率的考察和扫描电镜观察，研究微孔淀粉质量随不同酶浓度和处理时间的变化规律，并采用正交实验方法优化温度、pH和钙离子浓度等微孔淀粉制备的工艺条件。     

双酶法提取玉米胚芽油工艺研究

利用双酶法提取玉米胚芽油,研究了原料预处理方式、酶制剂种类、添加量、酶解温度、pH、时间等因素对油脂浸出率的影响.试验结果表明较适工艺参数为:颗粒度60目筛下物,湿热处理10 min,酶制剂种类为纤维素酶+中性蛋白酶复合酶制剂(w/w=4∶3),添加量1.0%,酶解温度50℃,pH 4.0,时间4 h,固液比1∶7,油脂浸出率可达81.4%.     

酶法提取玉米黄色素的工艺优化

以生产玉米淀粉的副产品玉米蛋白粉为原料.分别利用直接提取法和蛋白酶水解提取法从玉米蛋白粉中提取玉米黄色素.采用均匀设计实验的方法对提取进行优化.最佳水解条件为:中性蛋白酶在底物质量分数5%、酶质量分数1.4%、pH值7.0、温度40℃条件下水解6 h.     

银杏淀粉提取工艺研究

以银杏为原料,NaOH为浸泡剂,进行银杏淀粉提取工艺研究。探讨了碱液浓度、料液比、浸泡时间、浸泡温度对淀粉提取率的影响,并用正交试验确定了银杏淀粉的最佳工艺。结果表明,银杏淀粉提取的最佳工艺条件为:碱液质量分数为0.4%,料液比1∶7,浸泡温度45℃,浸泡时间3h。在此条件下,银杏淀粉的提取率为73.5%。     

中性蛋白酶辅助提取天麻淀粉的工艺优化

以新鲜天麻为原料、中性蛋白酶为酶解剂,通过单因素和正交试验研究料液比、酶解时间、酶解pH、酶添加量和酶解温度对天麻淀粉中蛋白质残留率和天麻淀粉得率的影响,并确定最佳提取工艺。结果表明：天麻淀粉提取最佳工艺为料液比1∶7(g/mL)、酶解时间2.5 h、酶解温度35℃、酶添加量0.8 mg/g、酶解pH 7.0,在此条件下天麻淀粉得率为12.49%,蛋白质残留率为0.006 8%。     

玉米湿法工艺提取淀粉的研究进展

湿法加工是一种常见的农产品加工工艺,可以分离出农产品中的不同组分,该文主要从玉米的自身性质及贮藏条件介绍湿法提取玉米淀粉的影响因素,论述传统湿法提取的弊端及局限性,介绍近年来诸如酶法、超声法、挤压法等一些新型高效、绿色的玉米淀粉提取方法,以期为加工中降低能源消耗和二氧化碳排放量提供参考。     

不同介质对玉米淀粉糊化黏度特性的影响

为研究食品添加剂对玉米淀粉糊特性的影响,采用Brabender黏度仪测定玉米淀粉在添加不同量的碳酸钠、明矾、食盐和蔗糖后的黏度曲线,结果表明:四种添加剂均使淀粉的糊化温度升高。随着碳酸钠和明矾添加量的增加,淀粉糊的峰值黏度、崩解值显著升高,消减值、回生值和最终黏度降低,淀粉糊的热稳定性、凝胶性降低,凝沉性增强;而蔗糖和食盐的加入使淀粉的崩解值降低,增强了淀粉糊的热稳定性。碳酸钠和明矾对糊化特性影响较大,蔗糖和食盐的影响较小。     

玉米淀粉辅料在啤酒生产中的应用

以玉米淀粉为辅料进行啤酒生产的研究结果表明,用量适当,不仅啤酒的成本降低,而且啤酒的发酵度、色度、总酸和非生物稳定性都较原工艺有一定的提高,泡持性有所降低,有利于生产淡爽型啤酒。     

大豆分离蛋白辅助干热改性玉米淀粉的流变特性研究

本文采用快速黏度分析仪(RVA)、流变仪、扫描电镜(SEM)对干热处理前后的普通玉米淀粉(CS)和蜡质玉米淀粉(WCS)与大豆分离蛋白(SPI)共混物的糊化特性、流变特性以及微观结构进行了研究。实验结果表明,与SPI干热处理后,淀粉的黏度明显增加,而WCS黏度的增加相比于CS更加明显。与未经干热处理的样品相比,干热混合物的G’、G"值显著增加,tanδ值明显降低。表明干热处理后,糊化后的淀粉凝胶网络结构增强,更加偏向于类固体的性质。SEM结果显示,与SPI干热使淀粉产生了聚集,CS/SPI产生了较小的聚集,而WCS/SPI形成了更大的块状聚集体。淀粉颗粒之间的聚集表明淀粉与SPI经干热处理后发生了相互作用,并且WCS与SPI的交互作用更加明显。SPI辅助干热改性可以作为蜡质玉米淀粉改性的新方法。     

The effect of an exogenous protease on the fermentation and nutritive value of high-moisture corn

The objective of this study was to determine if treating high-moisture corn at harvest with an exogenous protease could accelerate the increase in in vitro ruminal starch degradation that is normally found with advancing times of ensiling. Ground high-moisture corn (HMC; 73% dry matter) was untreated or treated with an exogenous protease to achieve a final concentration of 2,000 mg of protease/kg of fresh corn. Corn was ensiled in laboratory-scale bags (approximately 500 g) that were evacuated of air, heat-sealed, and stored at 22 to 23°C for 70 and 140 d. Samples of freshly treated corn samples were collected to represent d 0 samples. Treatment of HMC with protease did not affect the gross populations of lactic acid bacteria or yeasts throughout the ensiling period. Treatment of HMC with protease resulted in higher concentrations of lactic acid and ethanol after 70 but not 140 d of ensiling. Concentrations of crude protein, water-soluble carbohydrates, and starch were unaffected by treatment with protease within each sampling day. After 70 or 140 d of ensiling, HMC that was treated with protease had higher concentrations of soluble protein (as a % of crude protein) and NH₃-N, and had lower concentrations of prolamin protein, compared with untreated corn. In vitro rumen degradability (7-h incubation) of starch was greater in protease-treated versus untreated corn at all sampling days but the difference was more pronounced after 70 and 140 d compared with d 0. Concentrations of soluble protein and NH₃-N were positively correlated with in vitro starch degradation. Conversely, the concentrations of prolamin protein in HMC were negatively correlated with in vitro starch degradation. Treating HMC with an exogenous protease could be a method to obtain greater potential for ruminal starch fermentation after a relatively short period of ensiling.     

The effect of various doses of an exogenous acid protease on the fermentation and nutritive value of corn silage

The objective of this experiment was to evaluate the effects of treating whole-plant corn at harvest with various doses of an exogenous acidic protease on fermentation and changes in nutritive value after a short period (45 d) of ensiling. Whole-plant corn (37% dry matter) was chopped and treated with 0, 20, 200, 1,000, or 2,000 mg of protease/kg of wet forage. Forages (~500 g) were packed in bag silos and ensiled at 22 to 23°C for 45 d. Data were analyzed as a 5 × 2 factorial arrangement of treatments with the main effects of the dose of protease, day of ensiling, and their interaction. Treatment with protease did not alter the concentrations of dry matter, neutral detergent fiber, acid detergent fiber, starch, lactic acid, or acetic acid compared with untreated silage, with the exception that the concentration of starch was lower in silage treated with 20 mg of protease/kg compared with untreated silage. However, the 2 highest doses of protease resulted in silages with higher concentrations of ethanol and more yeasts compared with untreated silage. Protease treatment did not affect the ruminal in vitro digestibility of neutral detergent fiber. Concentrations of soluble protein (percentage of crude protein) increased after ensiling for all treatments but was not different between silage treated with the lowest dose of protease and untreated silage. Soluble protein increased in a dose-dependent manner above the low dose of protease in silages. Concentrations of NH₃-N were higher only in silages treated with the 2 highest doses of protease compared with untreated silage. Silages treated with the 3 highest doses of protease were higher in ruminal in vitro digestibility of starch compared with untreated silage but were similar to each other. The concentrations of total AA were determined in fresh forage and silages for the untreated and 200 and 2,000 mg/kg doses of protease. Neither amount of added protease affected the total concentrations of essential, nonessential, or total AA in silage. However, of the essential AA, treatment with protease resulted in silages with lower concentrations of lysine and arginine but higher concentrations of leucine compared with untreated silage. The 200 mg/kg dose of protease substantially improved ruminal in vitro starch digestion in corn silage after a short period of ensiling without affecting concentrations or numbers of ethanol and yeasts, respectively.     

产酸性蛋白酶微生物的筛选及其在玉米淀粉生产中的应用

分别从土壤和泡菜中筛选到适合玉米淀粉湿法加工浸泡条件(50℃,pH值3.5～5)的微生物,经形态学及分子生物学鉴定,初步确定该菌株为烟曲霉(Aspergillas fumigates);提取发酵液中的酸性蛋白酶粗酶进行酶学性质研究,发现该酶在50℃,pH值3.5～5下仍保持较高的稳定性;将发酵液应用于玉米淀粉湿法浸泡工艺中,优化的玉米浸泡条件为:浸泡温度50℃、乳酸含量0.5%、SO2含量0.08%,初次浸泡12 h,然后添加12%发酵液浸泡10 h。新工艺减少了环境污染,浸泡时间缩短了26 h,更有利于生产。     

超声波辅助酶解淀粉制备糊精的工艺研究

以玉米淀粉为原料,采用超声波处理对淀粉乳酶解前进行处理,然后酶解制备糊精,可获得分子分布更为均匀的糊精样品。超声波作用条件为：超声功率50W,超声全程时间范围可选择5～15min,超声波工作时间选择2～5s 范围,间隔时间可选择20s 以上。在此基础上调整加酶量或酶解时间,可获得不同DE 值的糊精样品。通过电镜观察,超声波处理会侵蚀淀粉颗粒表面,造成不同程度的破裂;高强度的超声波降解支链淀粉的作用增强,超声波处理制备的糊精分子分布更为均匀,并且大分子比例减少。     

响应面法优化酶法提取芋头淀粉工艺参数

采用碱性蛋白酶作为蛋白质酶解剂,对提取芋头淀粉的工艺进行研究。在单因素试验基础上,采用响应面设计优化提取芋头淀粉的工艺参数。结果表明：芋头淀粉酶法提取的最佳工艺参数为酶解时间137 min、酶用量0.9%、酶解温度41 ℃、pH 10,在此条件下芋头淀粉的实际提取率达88.92%。碱性蛋白酶法制得的芋头淀粉主要理化指标为蛋白质含量0.08%、白度94.45%、平均粒径1.23 μm。扫描电子显微镜图显示该提取方法未对淀粉颗粒造成损伤。     

酶解制备玉米肽的工艺优化研究

为了高效制备玉米肽,对玉米蛋白粉进行超声预处理,以多肽得率为评价指标,从Protamex、Alcalase、Flavourzyme、Protex.7 L、胰蛋白酶、木瓜蛋白酶等6种蛋白酶中筛选出Alcalase为最佳水解用酶.通过单因素试验和响应面分析确定制备玉米肽的工艺条件为:底物浓度10.0 g/(100 ml)、加酶量2 830 U/g、反应pH9.0、反应温度58.0℃、反应时间3h.在该条件下制备的玉米酶解产物的多肽得率为(46.61±0.37)％,与理论预测值的相对误差在±1％以内.