Effect of pH,temperature and maturity on pectinmethylesterase inactivation of citrus juices treated by high-pressure homogenization

The effects of high-pressure homogenization (HPH) at 150 MPa combined with heating at 58, 63 and 68 °C on inactivation of pectinmethylesterase (PME) were studied in orange and Clementine juices. Juices covering a range of total soluble solids (°Bx) to acid ratios (10.2–15.0 in oranges and 9.2–19.4 in Clementines) were adjusted to pH 3.1, 3.5 and 3.9 before homogenization. Results indicated how the residual PME activity of homogenized samples was greatly attenuated by lowering the pH and in a lesser extent by increasing the homogenization temperature (finding orange enzymes more HPH sensitive than their Clementine counterparts). Generally, ripeness of fruits had little influence on PME inactivation (especially in Clementine juices). In any case, orange and Clementine samples with pH 3.1 and homogenized at 68 °C showed residual PME activities below 10% of the initial value from their respective fresh juices.     

Determination of optimum processing conditions for hot‐air roasting of hulled sesame seeds using response surface methodology

Sesame paste (tahin) is produced by milling hulled, roasted, sesame seeds. In this study, a hot‐air roasting process for the production of sesame paste was optimised by response surface methodology (RSM) over a range of air temperatures (120–180 °C) for various times (30–60 min). The colour parameters (L, a and b values), browning index (BI), hardness, fracturability and moisture content of the seeds were used as response parameters to develop predictive models and optimise the roasting process. Increases in roasting temperature and time caused increases in the a and b values and in the BI. The hardness and fracturability of seeds also decreased with increasing roasting temperature and time. The quadratic and linear models developed by RSM adequately described the changes in the colour values and textural parameters, respectively. The result of RSM analysis showed that all colour parameters and textural parameters should be used to monitor the roasting of sesame seeds in a hot‐air roaster. To obtain the desired colour and texture, the optimum roasting range for production of sesame paste was determined as 155–170 °C for 40–60 min. Copyright © 2006 Society of Chemical Industry     

响应面法优化柑橘复合生物保鲜剂配方

以南丰蜜橘为原料,在单因素实验的基础上,采用响应面分析方法对生姜精油、茶多酚、壳聚糖、蔗糖脂肪酸酯(Sucrose Fatty Acid Esters,SE)生物保鲜剂进行复配优化。结果表明:南丰蜜橘的最佳复合生物保鲜剂配方为:茶多酚浓度1.60%、壳聚糖浓度2.25%、蔗糖脂肪酸酯浓度0.65%和生姜精油的浓度0.15%,在此最佳条件下,蜜橘在25℃下贮藏90 d后,其腐烂率为5.09%、失重率为3.40%、维生素C含量为510.56 mg/kg。此复合生物保鲜剂具有健康、环保、高效等优点,有望用于柑橘贮藏保存和保鲜的工业化生产中。      

响应面分析pH值、温度、SO_2对干红葡萄酒中吡喃花色苷Vitisins的影响

为提高甘肃河西地区葡萄酒色泽品质,试验以蛇龙珠葡萄为原料,在单因素试验的基础上,利用响应面法分析p H值、发酵温度和SO_2添加量对干红葡萄酒中吡喃花色苷Vitisins的影响,建立数学回归模型,分析因素间的交互作用。结果显示,影响Vitisin A和Vitisin B含量的显著单因素为SO_2添加量和发酵温度,而SO_2添加量和p H值的交互作用影响最显著。蛇龙珠干红葡萄酒的最佳酿造工艺参数为:SO_2添加量58.89 mg/L,发酵温度26.57℃,葡萄醪p H值3.92,此条件下试验样品Vitisin A和Vitisin B含量分别达(14.43±1.04)mg/L和(2.22±0.23)mg/L,与模型理论值吻合度高达90%以上。     

响应面法优化碱性水提取柑桔皮渣类黄酮工艺研究

试验使用氢氧化钠溶液调节纯水pH,得到pH为10的碱性水为提取溶剂,以热浸提方法提取柑桔皮渣中类黄酮。在单因素试验的基础上,利用三元二次旋转组合试验设计及响应面分析法,优化热浸提时间、温度及料液比,建立此3因素与类黄酮得率之间的数学模型。经试验确定碱性水提取柑桔皮渣中类黄酮的最佳工艺条件为:热浸提时间为2.2h、料液比为1:12(g/mL)、提取温度为64.6℃。在此最佳工艺条件下,类黄酮的得率为0.115%。     

Determination of the optimum mixture of transglutaminase,l-ascorbic acid and xylanase for the quality and consumer acceptability of bread using response surface methodology

The optimum levels of transglutaminase (TGase), l-ascorbic acid (l-AA), and xylanase (Xyl) were determined using response surface methodology to improve quality and consumer acceptability of bread made with wheat flour. A Box-Behnken design with three independent variables (TGase, l-AA, and Xyl) and three levels was used to develop models for the different responses (peak time, mixing tolerance, extensibility, resistance, specific volume, hardness, and consumer acceptability). Overall, l-AA and Xyl improved dough and bread properties, whereas the addition of TGase positively affected to texture and overall acceptability by consumer test. The optimal formulation for dough and bread properties and consumer acceptability were identified and the optimal value was 0.36 g/100 g TGase, 0.026 g/100 g Xyl, and 0.005 g/100 g l-AA. The results demonstrate that the addition of optimum amounts of TGase, Xyl, and l-AA improves the baking quality of the flour by enhancing dough properties and increase the consumer acceptability of the bread.     

响应面法优化长白山野菊花挥发油的提取工艺及成分分析

采用索式提取法对长白山野菊花挥发油进行提取,在单因素试验的基础上,以挥发油得率为指标,利用响应面法优化长白山野菊花挥发油提取工艺条件,确定最佳提取工艺条件。在抽提温度50.17℃,料液比1∶40(g∶m L),提取时间9.44 h的条件下,长白山野菊花挥发油得率可达4.953 62%,提取率达到95%以上。应用GC-MS测定挥发油中的主要成分有α-香树精、桉叶油素、乙酸龙脑酯、1,4-桉叶素、β–倍半水芹烯、(+)–雪松醇、红没药醇、右旋樟脑、异龙脑、石竹素以及(-)-α-柏木烯,均为倍半萜类化合物及其含氧衍生物,其中α-香树精含量为9.02%,也是长白山野菊花挥发油中特有的成分之一。     

响应面法优化茶渣水不溶性膳食纤维的提取及性能研究

以石阡苔茶茶渣作为实验材料,碱提法对水不溶性膳食纤维进行提取。采用Design-Expert V8.0软件中的Box-Behnken（BBD）中心组合原理设计响应面实验,考察浸提温度、料液比、碱浓度、浸提时间对水不溶性膳食纤维提取率的影响,优化提取工艺,结果表明:优化的最佳提取工艺条件为:浸提温度32.6℃、碱浓度0.2mol/L、浸提时间50min、料液比1∶13.5（g/m L）,茶渣中水不溶性膳食纤维的提取率为78.66%;性质研究的结果表明:提取得到水不溶性膳食纤维的持水力为183.92%,溶胀度为2.83m L/g。由此可知,响应面法优化提取水不溶性膳食纤维具有时间短、能耗低、提取率高等特点。      

Optimization of pea protein and citrus fiber contents for plant based stirred soymilk yogurt using response surface methodology

Food Science and Biotechnology - This study investigated the optimization of pea protein (PP) and citrus fiber (CF) contents with the goal of producing a clean-label plant-based stirred soymilk...     

在线反应-高效液相色谱联用分析pH值对柑橘汁环氧佛手柑素水合反应的影响

该研究开发了一种基于HPLC自动进样系统的化学反应过程在线分析方法,以研究不同酸度的模拟柑橘汁中6',7'.环氧佛手柑素(6',7'.epoxybergamottin,6',7'.EB)的酸诱导反应产物和速率。编辑样品自动处理程序,使反应物在pH 2.0、3.5和5.0的25℃模拟果汁中充分反应,并优化色谱条件使反应物和主要产物完全分离,实现反应体系的周期性进样和分析;利用二极管阵列检测器和外标法对各物质进行定性和定量检测。6',7'.EB在25℃酸催化下主要发生侧链环氧基开环水合反应,生成6',7'.二羟佛手柑素,同时产生少量异欧前胡素,两反应均为一级反应;6',7'.EB在pH 2.0和3.5条件下的半寿期分别为9.71和119.7 min,在pH 5.0时基本稳定。该方法实现了对6',7'.EB水合反应速率的自动化在线分析,具有精度高和省时省力的特点,所得pH 35反应速率常数能较准确地预测葡萄柚汁中6',7'.EB及其产物的浓度。     

响应面分析法优化糟醉带鱼的糟醉工艺

采用响应面分析法对糟醉带鱼的糟醉工艺进行优化。在单因素实验基础上,根据中心组合实验设计原理,采用三因素三水平的响应面分析法,以糟醉带鱼的感官评分为响应值进行回归分析。结果表明,糟醉带鱼糟醉的适宜工艺条件为加盐量4.7%,加酒量7.1%,糟鱼比1:2.2,在此条件下制得的糟醉带鱼感官评分最优,达到84.5分,与模型预测值基本相符。      

响应曲面法优化rmHSA-GCSF的发酵工艺

采用Plackett-Burman设计法对影响巴斯德毕赤酵母(Pichia pastoris)表达重组人血清白蛋白-粒细胞集落刺激因子突变体(rmHSA-GCSF)的主要参数进行了摇瓶试验,选取到3种显著效应的因素:诱导pH、甲醇添加浓度和诱导时间。再利用响应曲面法(Response surface method)对这3种因素进行进一步研究,得到最佳培养条件:甲醇诱导浓度为2.45%,诱导pH为5.54,诱导时间为66.4 h。采用此优化参数,rm HSA-GCSF表达量的最大预测值达157.5 mg/L。此后,根据优化的培养条件,进行150 L发酵罐放大试验,rm HSA-GCSF表达量达到600 mg/L左右,成功实现rm HSA-GCSF的高效表达。     

响应面法优化马奶酒发酵条件的研究

以新鲜马奶为原料,通过考察接菌量(乳酸菌/酵母菌)、发酵温度、发酵时间、糖添加量单因素试验对马奶酒发酵的影响,并借助响应面设计,研究接菌量(乳酸菌/酵母菌)、发酵温度、发酵时间对马奶酒品质的影响。结果表明,最佳发酵条件分别为接菌量(乳酸菌/酵母菌)3%∶5%、发酵温度32℃、发酵时间80h、糖添加量6%。马奶酒酒香清雅,微酸爽口。     

响应面分析法优化糟醉带鱼的糟醉工艺

采用响应面分析法对糟醉带鱼的糟醉工艺进行优化.在单因素实验基础上,根据中心组合实验设计原理,采用三因素三水平的响应面分析法,以糟醉带鱼的感官评分为响应值进行回归分析.结果表明,糟醉带鱼糟醉的适宜工艺条件为加盐量4.7％,加酒量7.1％,糟鱼比1∶2.2,在此条件下制得的糟醉带鱼感官评分最优,达到84.5分,与模型预测值基本相符.     

响应面法优化可得然胶发酵培养基

可得然胶是细菌在氮源限制条件下生成的水不溶性胞外多糖。发酵培养基的各组分配比对可得然胶的产量有极大的影响。因此,优化发酵培养基对提高可得然胶产量有重要意义。本文采用响应面分析法对可得然胶的发酵培养基进行优化设计。通过Plackett-Burman实验进行重要因素筛选,得出影响可得然胶产量的主要因素为:蔗糖、（NH4）2HPO4、MgSO4和玉米浆。利用最陡爬坡实验逼近响应区域,应用Box-Behnken实验设计和响应面法分析优化得到最佳的发酵培养基为:蔗糖61g/L、MgSO41g/L、玉米浆2.5mL/L、（NH4）2HPO42.4g/L、KH2PO41.4g/L、CaCO31.4g/L。发酵结果（47.73g/L）与优化之前（35.2g/L）的可得然胶产量进行比较,优化后的产量提高了35.6%。      

响应面法优化虫草培养的研究

利用响应面分析法,研究蔗糖、牛肉膏和pH值对虫草菌生长生物量的影响。结果表明:营养源的种类和浓度对虫草菌生物量有很大的影响,在所选用的蔗糖、葡萄糖、柠檬酸铵、淀粉和牛肉膏、蛋白胨、硫酸铵七种营养源中,蔗糖和牛肉膏最利于虫草菌的生长,浓度以2%左右为宜;当蔗糖的浓度为2.74%、牛肉膏浓度为1.86%、pH值为7.37时,虫草菌C.FFCC5124的生物量为10.2g/L。响应面试验的方差分析表明:一次项对响应值的影响很显著,其次为平方项,而交互项影响较为微弱。     

响应面法优化奶啤发酵工艺参数

以鲜奶为主要原料,乳酸菌和酵母菌为主要发酵菌种,通过发酵试验和感官评定,筛选出影响奶啤发酵的重要参数.通过Box-Behnken试验设计确定重要参数的最佳水平,和最佳的参数.影响奶啤发酵的重要参数发酵温度为30℃,酵母菌接种量为11%,总发酵时间为21 h,此状态下奶啤饮料风味最佳,感官评分可达95.5.     

Optimising the frying temperature of gluten balls using response surface methodology

The continuous frying process of gluten balls involved three consecutive deep frying pans. The effects of the temperatures of the first and the second deep frying pans on the quality indices of the obtained fried gluten balls, including expansion volume, expansion ratio, measured value of textural property, Hunter colour b value, and sensory evaluation score, were investigated using response surface methodology while fixing the temperature of the third deep frying pan at 195±3°C. Based on the obtained sensory evaluation scores, the peak force and brittleness breakdown of textural properties, as well as Hunter colour b value of the fried gluten balls, it was found that the optimum temperature ranges for the first and the second deep frying pans were 130–143°C and 155–161°C, respectively. © 1998 SCI.