米糠复合酶解工艺条件研究

以膨化米糠为主要原料,先经α-淀粉酶液化,再经糖化酶和蛋白酶同步酶解,改善米糠液中的营养成分。试验结果表明,α-淀粉酶水解最佳条件为酶用量1.5%,酶解温度为80 ℃,酶解时间为75 min,淀粉酶水解后还原糖含量达到0.657 1 g/100 mL。糖化酶和蛋白酶复合水解米糠,最适条件为pH4.5,糖化酶添加量0.2%,蛋白酶添加量2%,酶解温度60 ℃,酶解时间120 min,在此条件下,酶解液还原糖含量可达3.0 g/100 mL,氨基酸含量可达5.2 g/100 mL。     

混合酶在澄清荔枝汁中的应用研究

采用正交设计研究了果胶酶、纤维素酶、木瓜蛋白酶和α-淀粉酶联合使用对荔枝果汁澄清度、稳定性与营养成分的影响。结果表明,混合酶用于澄清荔枝汁的最优工艺条件是纤维素酶量600U/100g,果胶酶量1000U/100g,α-淀粉酶量250U/100g,木瓜蛋白酶量10000U/100g,酶解温度60℃,酶解时间4h,PH4.0,且pH为主要影响因素。与原汁相比,经混合酶处理后的荔枝澄清汁的稳定性得到提高,且可溶性固形物、总糖、还原糖、总酸和氨基酸含量也明显得到提高。     

草莓胡萝卜复合果蔬汁澄清工艺研究

澄清是复合果蔬汁加工过程核心技术之一,处理不好直接影响果蔬汁品质。果胶酶作为常用澄清剂,具有简便、快捷、效果好等特点。本文以果胶酶为澄清剂,研究了果胶酶用量、酶解温度、酶解时间和复合果蔬汁pH对草莓胡萝卜复合果蔬汁的澄清效果。单因素试验显示:果胶酶用量为0.65 0.75g/L、酶解温度为40 50℃、酶解时间为3.5 4.5h、复合果蔬汁pH为3.5 4时,草莓胡萝卜复合果蔬汁的出汁率和透光率均较好。通过正交试验获得的最佳工艺条件为:果胶酶用量0.7g/L、酶解温度50℃、酶解时间5h、复合果蔬汁pH值3.75,此条件下澄清后草莓胡萝卜复合果蔬汁透光率为80.34%,出汁率为88.73%,可溶性固形物含量为10.8%。本研究结果表明,在合适的工艺条件下,果胶酶能有效的去除草莓胡萝卜复合果蔬汁中的果胶物质。     

雪莲果梨果醋澄清工艺的优化研究

以果胶酶为澄清剂对雪莲果梨果醋进行澄清处理,研究了果胶酶用量、酶解pH、酶解温度和酶解时间对雪莲果梨果醋澄清效果的影响,在单因素试验的基础上,采用正交试验对酶用量、酶解pH、酶解温度和酶解时间等工艺参数进行优化,得到最佳工艺条件为:果胶酶用量0.03%、酶解pH 3.5、酶解温度40℃、酶解时间150min,该条件下澄清后果醋透光率为89.3%,澄清效果好。     

果胶酶对芦荟汁的澄清作用及性质的影响

为提高芦荟汁的澄清度,以果胶酶为澄清剂,透光率为评价指标,研究了酶解时间、酶解温度及加酶量对芦荟汁澄清效果的影响,通过单因素试验及正交试验得到最佳工艺条件是：果胶酶添加量0.1 μL/g,酶解时间120 min,酶解温度45 ℃,在此最佳条件下,芦荟汁的透光率为91.1%。酶解后的芦荟汁在感官品质方面,颜色变浅、涩味变淡、悬浮物减少、澄清度提高;在理化性质方面,pH值稍有下降、透光率提高了31.2个百分点,还原糖及可溶性固形物含量均提高至原来的2.0倍左右,芦荟多糖含量显著下降。     

枸杞山楂复合果汁的澄清工艺条件研究

研究了使用果胶酶澄清枸杞山楂复合果汁的工艺条件,结果显示,在果胶酶用量5g/L、果汁pH3.2、酶解温度50℃、酶解时间2.5h的工艺条件下澄清的枸杞山楂复合果汁,透光率可达94.8%。果胶酶能有效地去除枸杞山楂复合果汁中的果胶物质。     

果胶酶对布朗李汁澄清效果的影响

采用河南省平顶山市市售布朗李为原料进行研究,探讨果胶酶对布朗李汁澄清效果的影响,以期获得布朗李汁的最佳澄清工艺参数.对布朗李基本营养成分进行测定并通过单因素 (果胶酶用量、果胶酶作用时间、果胶酶作用温度) 试验和L9 (34) 正交试验对布朗李汁澄清工艺进行研究.试验结果表明:布朗李果实含水87.92%,总糖10.81%,总酸0.59%,可溶性固形物13.12%,维生素C 8.49mg/100g,单宁507.4mg/100g.果胶酶对布朗李汁澄清效果的最佳工艺参数为果胶酶用量0.03%,酶作用时间2.0h,酶作用温度55℃.在最优组合条件下其透光率可达94.2%,此时测定布朗李汁的单宁含量为32.7mg/100mL.所得结果可为布朗李果汁饮料的生产加工提供参考.     

果胶酶低温处理山楂鲜果浆制备山楂酒工艺优化

由于山楂中存在大量果胶,制作山楂酒需对山楂果浆进行澄清处理。现有工艺多采用高温浸提或高温酶解的方式,两种处理方式温度较高,对山楂风味及营养都有不利影响。本研究通过优化果胶酶的处理温度、添加量、处理时间等条件,开发新型低温酶解工艺处理山楂鲜果浆,进而制备发酵山楂酒。本研究发现在35℃条件下添加0.15 m L/L果胶酶处理4 h后,山楂鲜果浆的透光率可高达93%。同时该工艺相比未添加果胶酶处理的山楂果浆,还原糖含量由8.2 g/L上升至14.2 g/L,总酸含量从5.5 g/L上升至7 g/L,对还原糖和总酸的提取效果较好。测定35℃处理山楂果浆主要风味指标优于果胶酶55℃酶解处理发酵的山楂酒。     

果胶酶对玫瑰香橙汁澄清效果的影响

以果胶酶为澄清剂,研究果胶酶用量、pH、温度和时间对玫瑰香橙汁澄清度的影响。通过单因素试验,并利用Box-Benhnken中心组合设计,进行澄清条件优化。结果表明,果汁透光率测定最佳波长为685 nm,澄清最佳工艺参数为果胶酶用量0.09 g/L,酶解温度31 ℃,果汁pH值为3.9,酶解时间120 min。在此最佳条件下,玫瑰香橙汁的透光率为98.00%。     

果胶酶澄清菠萝汁最佳工艺研究

用果胶酶对菠萝浆进行酶解及最佳澄清工艺条件试验。单因素试验研究了果胶酶用量、酶解温度和酶解时间分别对菠萝汁透光率、可溶性固形物、出汁率、果胶含量的影响。在此基础上,通过二次正交旋转回归试验,得出了酶解条件的回归方程,确定了果胶酶对菠萝汁澄清的最佳工艺条件为果胶酶用量为80mg/kg、温度25℃、时间为60min。     

热协同超高压处理对含防褐变剂鲜榨苹果汁贮藏品质的影响

采用HPLC等分析方法研究了400MPa单独处理,50℃协同300MPa处理和50℃单独处理对含防褐变剂鲜榨苹果汁在4℃贮藏时品质的影响。研究发现:经过45d的贮藏,仅经过400MPa压力处理的和仅经过50℃处理的果汁中酚类物质含量比经过50℃协同300MPa处理的含量低,差异显著(P<0.05)。50℃协同300MPa处理还可显著降低果汁中微生物数目,同时果汁在贮藏期内的L值和a值均优于其他2种样品。50℃协同300MPa处理鲜榨苹果汁的可溶性固形物含量和pH值贮藏前后没有显著差异(P>0.05)。经过贮藏,所有样品中的总VC的保留率>95%。     

果胶酶制剂在澄清苹果汁加工中的应用研究

利用果胶酶制剂处理苹果(品种:国光)、果浆、果汁,结果表明:0.1％的Pectinex Ultra SP果胶酶处理可明显地提高出汁率、可溶性固形物和透光度;降低pH值和相对粘度,处理效果随作用时间增加而增加,对不同贮藏期的苹果处理效果不同。0.1％的TL-enzyme果胶酶与0.1％的纤维素酶结合处理的效果大于0.1％的TL-enzyme果胶酶单独处理的效果。在20～22℃,汁中添加不低于0.1％的黑曲霉(As 3.316)果胶酶或不低于0.001％的Ultrazym100G果胶酶,可分别在8小时和6小时内使果汁澄清;处理温度提高或酶浓度加大,澄清时间缩短。用Ultrazym100G果胶酶澄清的汁,其糖分、滴定酸含量没有明显变化,单宁物质含量降低,矿质元素和沉淀中粗蛋白含量发生变化。     

苹果浓缩汁美拉德反应有关影响因素的研究

以苹果制汁新品种鲁加1号和鲁加3号[特拉蒙(Telemon)×富士(Fuji)]的浓缩果汁为试材,研究了苹果浓缩汁贮藏过程中氨基酸、还原糖和5-羟甲基糠醛(5-HMF)含量的变化,并利用几种氨基酸和还原糖分别在柠檬酸-磷酸缓冲液(pH3．20)与苹果浓缩汁中进行美拉德模拟试验。实验结果表明:贮藏过程中,苹果浓缩汁中的赖氨酸、苯丙氨酸、亮氨酸、异亮氨酸、蛋氨酸、苏氨酸的含量呈下降趋势;还原糖含量成波浪式变化,即先上升后下降,然后上升再下降;5-HMF含量先上升后下降;在柠檬酸-磷酸缓冲液中进行美拉德模拟试验其氨基酸与还原糖的反应活性分别与苹果浓缩汁中的反应活性存在较大差异,在两个实验中赖氨酸都具有较大的反应活性。     

Influence of Storage on the Composition of Clarified Apple Juice Concentrate

The effect of storage on apple juice concentrate was determined by following changes in composition during a period of 111 days at 37°C. Results showed that storage caused an 87% loss in the total free amino acids, which was mostly due to decreases in glutamic acid, asparagine and aspartic acid. The forml titration method was inadequate for determining the amino compounds involved in Maillard-type reactions. Sucrose was hydrolyzed under these conditions at a rate corresponding to a fist order process. The reducing sugars increased at a rate determined by the inversion of sucrose; no consumption attributable to browning reaction was detected. Reduction of organic acids was 9% while apparent phenolic compounds increased from 0.149 to 0.215 g/100g. A maximum accumulation of HMF was observed after 100 days of storage.     

STUDIES ON PRESERVATION OF SUGARCANE JUICE

ABSTRACT

The variety CoP 92226 was selected for preparing sugarcane juice beverage on the basis of yield and sensory attributes from eight promising varieties of sugarcane. Sugarcane juice beverage samples were prepared by pasteurizing the sugarcane juice at 70°C for 10 minutes and adding citric acid (40 mg/100 ml), ascorbic acid (40 mg/100 ml) and potassium metabisulphite (150 ppm). Samples of sugarcane juice beverage were stored at room (30±5°C) and refrigeration (4±2°C) temperature in pre-sterilized glass bottles and analyzed for physico-chemical, microbiological and sensory attributes at every 15 days interval for 90 days. The pH, total soluble solids and total sugars decreased, whereas, titratable acidity and reducing sugars increased significantly (P<0.01) during storage. An appreciable increase in total plate counts and yeast and mold counts were observed, however, no coliforms, were detected in sugarcane juice beverage during storage. The changes in different attributes were significantly (P<0.01) higher at room temperature as compared to refrigeration temperature. The sugarcane juice beverage having citric acid and potassium metabisulphite showed minimum changes in sensory qualities during storage, both at room and refrigeration temperature. An acceptable quality beverage of sugarcane juice with satisfactory storage stability for 90 days at room as well as refrigeration temperature could be prepared.     

超高压处理对猕猴桃汁品质的影响

为了研究超高压处理对猕猴桃汁品质的影响,对新鲜猕猴桃进行200～500MPa超高压处理。结果表明：超高压猕猴桃汁中可溶性固形物、总酸、pH值等指标随压力升高变化不显著,VC及叶绿素含量有少量降低,香气成分中酸类、醛类物质在超高压处理后增加,酯类、醇类物质减少。超高压猕猴桃汁4℃条件下贮藏28d时VC损失21.8%,叶绿素损失40.5%,果汁趋于变质;－18℃条件下贮藏120d时,VC损失14.6%,叶绿素损失20.8%,因此－18℃贮藏条件能较好保持超高压处理后猕猴桃汁的营养物质。     

复合果蔬汁饮料青椒苹果汁的研制

主要研究青椒苹果汁饮料的制作方法,确定其基本配方为：苹果原汁10%～20%、青椒原汁10%、白砂糖8%～10%、柠檬酸0.3%、柠檬酸钠0.05%。苹果原汁生产中采用抗坏血酸护色与微波灭酶相结合,具有较好的抗褐变效果。青椒原汁生产中采用果胶酶提高青椒出汁率,效果显著。最佳酶解条件为：果胶酶添加量0.01%、加水量40%、酶解温度50℃、酶解时间40min、酶作用pH3.0,此条件下青椒出汁率可提高至57%,比未经酶处理的出汁率23.4%高出33.6%。     

Time and Temperature Effect on Stability of Moroccan Processed Orange Juice during Storage

The loss of quality of processed pasteurized orange juice stored at 4°C, 22.5°C, 35°C, and 45°C for up to 14 wks was evaluated. The results showed that parameters such as pH, total solids, titratable acidity, formal index, and total sugars did not significantly change during storage at all temperatures. However, a major change was observed for ascorbic acid content, reducing sugars and furfural production, except for storage temperature at 4°C. Ascorbic acid degradation, sucrose hydrolysis, and furfural build-up followed pseudo-zero order reaction kinetics. The minimal change of formol number and total sugars suggested that nonenzymatic browning was mainly due to ascorbic acid degradation. Fufurfal formation during storage was found to be much higher than that reported in the literature.