猕猴桃澄清果汁加工工艺研究

利用壳聚糖聚阳离子电解质的特性澄清猕猴桃汁,选择壳聚糖脱乙酰度、壳聚糖加入量、果汁pH、加入壳聚糖后47℃果汁保温时间与澄清果汁的透光率的关系进行单因素实验,并在单因素实验基础上用拟因子正交实验设计,找出了澄清猕猴桃原汁的最优条件为:用脱乙酰度80%的壳聚糖,加入量为0.4g/L,加入壳聚糖后果汁于40℃保温40min,果汁pH为自然pH值,壳聚糖澄清猕猴桃汁之后离心时间为30min;影响澄清猕猴桃汁的显著因素为壳聚糖的脱乙酰度、加入壳聚糖后果汁的保温时间和离心时间。     

冷冻与酶解相结合澄清芦柑果汁的工艺研究及质量评价

研究冷冻法与果胶酶酶解法相结合对芦柑果汁的澄清作用,同时探讨此澄清方式对果汁品质的影响。实验以新鲜芦柑果肉为原料,先进行冷冻预处理,自然解冻榨汁、离心后再用果胶酶对果汁进行澄清。结果表明,芦柑果肉冷冻预处理的最佳温度为—20℃、时间为60 min,得到的果汁透光率和出汁率分别为80.57%、82.86%;果胶酶酶解的最优工艺参数为:酶添加量0.05 g/L、酶解温度45℃、酶解时间0.5 h,酶解处理后果汁的透光率和出汁率分别达到94.16%、90.38%;经冷冻与酶解相结合处理后汁液的Vc含量由26.77 mg/100 g降为25.48 mg/100 g,可溶性固形物及总糖下降较多,分别由9.6%、10.2 g/100 mL降为8.4%、7.8 g/100 mL,果胶和可溶性蛋白质几乎被完全分解;澄清汁储存稳定性良好。因此,该复合澄清工艺合理可行,可为芦柑果汁的深加工提供理论依据。     

西番莲果汁加工工艺研究

介绍了西番莲果汁的一种加工工艺及操作要点,探讨了选择西番莲适宜加工成熟度方法以及提高果汁出汁率、增强果汁稳定性的工艺条件。结果表明,添加0.05%α-淀粉酶,0.25%果胶酶,在45℃下酶解2.5h后离心过滤可较好的提高西番莲果汁出汁率;同时,通过添加0.15%黄原胶,0.15%羧甲基纤维素钠,在25～30MPa压力下均质3次,可得到稳定性较好的西番莲果汁。     

温差-超声波复合花粉破壁工艺的研究

采用温差并结合超声波辅助的复合花粉破壁法对花粉进行破壁,先对温差法进行正交试验L9(34),得到的最佳工艺条件为温差100℃、水浴时间7h、料液比1:10、冷冻时间24h,在此条件下,花粉的破壁率为61.61%。接着对温差处理过的样品继续进行超声辅助破壁工艺研究,采用正交试验L9(33),在功率为200W的情况下,得到最佳工艺为超声温度60℃、时间30min、浓度5%,此时花粉的破壁率达到88.53%。     

搅拌型猕猴桃、红枣汁复合保健酸奶的研制

以猕猴桃、红枣汁和鲜乳为主要原料,对搅拌型果汁酸乳的生产工艺进行了系统研究.通过鲜乳发酵,然后再加入果汁,得出搅拌型酸乳的最佳工艺条件为采用90～95℃、10min热处理牛乳,接种量2%,在42℃下培养3.5h,加8%蔗糖、5%猕猴桃汁、10%红枣汁,以0.2%耐酸CMC-Na作为稳定剂,在72～75℃、5～10min对成品进行杀菌.     

苹果-刺梨混浊汁生产工艺的研究

研究苹果-刺梨混浊汁的生产工艺,以新鲜苹果和刺梨为原料制混浊汁,采用感官评定和色差分析苹果与刺梨的配比对混浊汁色泽稳定性及风味的影响;采用浊度测定、色差分析和酚类测定等方法,研究苹果的前处理温度和时间、均质及其与离心的先后顺序对混浊汁混浊稳定性的影响.结果表明,苹果与刺梨的比例为45:1(W:W)时,果汁在加工过程中具有很好的色泽稳定性,且风味很好;苹果在45℃水浴中处理45 min,混浊汁具有很好的混浊稳定性;混浊汁在25 MPa、60℃均质后再离心(4 000 r/min,15 min),具有很好的贮藏稳定性.     

温差-超声波复合法对核桃花粉破壁率的影响

采用温差-超声波结合的方法对核桃花粉进行破壁处理,考察了不同处理条件对核桃花粉破壁率的影响,并在单因素实验的基础上,以花粉破壁率作为指标采用正交实验优化破壁工艺,得到温差-超声复合破壁的最佳工艺条件为:料液比1:15 g/m L、温差110℃、冷冻时间18h、超声时间35 min、超声功率720 W,此条件下核桃花粉破壁率为83.79%。     

酶制剂在澄清香蕉汁加工中的应用

利用淀粉酶、果胶酶制剂处理香蕉果浆,结果表明:在55℃下,香蕉果浆中加入0.4％的淀粉酶酶解30min,可明显提高香蕉果汁的得汁率;在45℃下,香蕉果汁中加入0.015％的果胶酶酶解60min,可明显提高香蕉果汁的澄清度。     

热处理条件对刺梨果汁风味物质和营养成分的影响研究

为了探讨刺梨果汁加工中的稳定性,本实验以刺梨果汁为研究对象,在62℃杀菌30 min、71℃杀菌10 min、71℃杀菌30 min、85℃杀菌10 min和95℃杀菌10 min的加热条件下,分析刺梨果汁风味物质及相关品质指标的变化。结果表明:刺梨汁中的挥发性风味物质含量较高的是壬醛、叶醇和油酸乙酯,热处理后醛类物质增加,醇类、酯类、烯类物质减少;采用Z-分综合评价法对不同热处理条件下刺梨果汁的菌落总数、维生素C(VC)、黄酮含量、超氧化物歧化酶(SOD)活性和褐变度的综合评分,得出71℃,10 min条件对刺梨果汁风味及品质变化影响较小。     

玫瑰香葡萄汁冷冻浓缩响应面工艺优化与品质研究

探讨利用冷冻浓缩方法获取高浓度、口感优良、便于保存、市场价值高的玫瑰浓缩葡萄汁,结合冷冻浓缩过程中冰晶的生长规律及生长机理,将葡萄汁冷冻浓缩工艺参数进行响应面优化,并比较多级冷冻浓缩汁与鲜汁理化指标之间的差异,分析得出冷冻工艺对浓缩葡萄汁的实操可行性。结果表明:冷媒温度-15.0℃,果汁浓度15.4°Brix,冷冻时间93.6 min时冷冻浓缩效果最佳。多级冷冻浓缩后葡萄汁中黄酮、总酚、维生素C等营养物质保存良好,保留率分别为81.9%、78.2%、78.5%;冷冻工艺对总糖、pH值、总酸含量无显著影响(P0.05),浓缩后果汁能够有效保留葡萄汁原有营养成分,具有投入市场的优良前景。     

路边青多酚复配物对猕猴桃饮料的抗氧化稳定性影响

在猕猴桃饮料中添加路边青- 过路黄多酚复配物,考察紫外光、温度和氧化剂对饮料过氧化值的影响以及复配物配比与羟自由基清除率的关系。结果表明：90℃温度下加热6h,猕猴桃饮料中添加路边青- 过路黄多酚复配物(1:1,V/V)其过氧化值比加BHT 和不加抗氧剂分别减少8.55% 和24.57%;分别用0.5% H2O2 氧化处理和紫外光照射,添加复配物的猕猴桃饮料,其过氧化值比加BHT 分别减少9.08% 和1.83%,比不加抗氧剂分别减少17.55% 和3.57%。路边青- 过路黄多酚复配物配比以3:1(V/V)的抗氧化活性最好,饮料中添加该复配物,其过氧化值比不加抗氧剂减少56.27%;羟自由基清除率是BHT 的1.37 倍。     

益生菌发酵猕猴桃汁工艺优化及香气成分动态解析

以感官评分和活菌数为评价指标,首先筛选获得适宜于天然猕猴桃果汁发酵的耐酸、耐胆盐益生乳酸菌菌株,其次优化建立猕猴桃汁乳酸菌发酵工艺条件,并利用电子鼻对发酵期间猕猴桃汁香气成分变化进行动态解析。结果表明：以筛查获得的植物乳杆菌21805和嗜酸乳杆菌20250混合发酵猕猴桃汁的最优工艺条件为接种量3%、发酵时间24 h、菌种比例11、发酵温度36 ℃,在此条件下得到感官评分为81.45 分,活菌数为2.185×108 CFU/mL。在此条件下,结合线性判别分析（linear discriminant analysis,LDA）和载荷分析,利用电子鼻检测猕猴桃汁发酵过程中的香气,结果表明LDA可准确区分发酵不同阶段的猕猴桃汁,证实了电子鼻可以检测发酵猕猴桃汁的香气变化,不同发酵阶段风味差异可能来源于萜烯类,其他还有醇类、烷类、芳香类化合物等,发酵8 h开始形成发酵香气,12 h是产生香气物质的关键时间点,发酵后期是生成发酵猕猴桃汁风味的关键阶段。     

果胶酶ROHAPECT D 5S对猕猴桃取汁和澄清的影响

研究了果胶酶ROHAPECTD5S对猕猴桃出汁率、粘度、澄清度和冷热稳定性的影响。结果表明,此酶可以极大地改进猕猴桃果浆的出汁率和降低果汁粘度,使果汁的澄清度加大,对冷冻和加热的稳定性加强。适合用作猕猴桃汁的加工,对猕猴桃浆的最佳应用条件为3PA/100g果浆(相当于干酶60G/1000kg果浆),45℃下60min。     

Effect of processing treatments on the characteristics of juices and still ciders from Ontario‐grown apples

Recent interest in the commercial production of cider in Ontario, Canada revealed a lack of information on cider prepared from apples grown in North America. A study was conducted using locally grown culinary and dessert varieties of apples, since there is a lack of true cider varieties grown in Ontario. Four processing methods (treatments) were evaluated with respect to their effect on juice and cider characteristics; the chemical and microbiological characteristics of the juices and still ciders are reported. Sulphite addition to the juice at the time of juice extraction had no effect on the characteristics evaluated. Storage of fruits at 13 °C until they showed signs of shrivelling or senescence decreased juice yield and affected titratable acidity and pH levels of juices and ciders. Freezing fresh apples and thawing prior to processing produced juices that did not undergo keeving and had higher mould and yeast populations; methanol was present in juices and ciders from thawed apples. The significant effects of storage and freezing on apple juice characteristics should be taken into account when considering a delay in the processing of apples for cider production. © 2003 Society of Chemical Industry     

Structural Stability of Fresh and Frozen-Thawed'Valencia'(C. sinensis) Orange Juice

Valencia orange juice was subjected to different freezing rates and different storage times to study the effects of those treatments on the structural and dispersion properties of the insoluble particles. Examination with an electron microscope revealed that the juice contained plastids, mitochondria, oil droplets and cell walls. Fragments consisting mainly of vesicular membranes were present both before and after freezing and thawing. A slow freezing rate resulted in plastids with various degrees of disintegration. Separation of insoluble particles from the juice serum increased with increasing frozen storage time and was especially apparent at slower primary freezing rates. A decrease in color intensity and deterioration in appearance is related to longer storage time and to slower primary freezing rates.     

果浆酶和果胶酶对猕猴桃出汁率的影响

为制取猕猴桃汁,通过单因素和正交试验,以出汁率、VC保存率和果汁色泽香气变化为指标,用果浆酶和果胶酶对猕猴桃进行酶解处理,探索更适合的猕猴桃制汁工艺条件。结果表明：两种酶都能大幅提高猕猴桃的出汁率,果胶酶酶解条件较剧烈,虽出汁率较高,但对VC含量和果汁色泽香气影响较大;果浆酶酶解条件较温和,总体指标较好,最佳酶解条件为酶解温度30℃、果浆酶加酶量10000U/kg、酶解时间2h、出汁率0.853mL/g,VC保存率67%。果浆酶更适合猕猴桃果汁的制取。     

冻融-超声提取高三萜酸含量山楂汁的工艺条件优化

为了优化提高山楂汁中三萜酸含量的工艺条件,分析冷冻时间、超声温度、超声时间和超声功率对山楂汁中三萜酸含量的影响。确定高三萜酸含量的山楂汁制备最佳工艺条件为：冷冻20 h,超声温度50 ℃,超声功率150 W,超声提取40 min。在优化条件下提取的山楂汁中三萜酸含量为341.18 mg/100 g,冻融-超声提取是一种制备高含量三萜酸山楂汁的有效技术。     

发酵猕猴桃汁的研究(II)——风味成分的鉴定

应用TenaxGC吸附法和GC-MS分析鉴定了不同猕猴桃汁的风味成分,结果表明,加菌发酵猕猴桃汁共有14种挥发性组分,加菌发酵过滤汁分离到12种组分,自然发酵汁共分离鉴定出17种组分,未发酵汁鉴定出13种组分。3类发酵汁均以呈现多种花香、果香的酯类为主,而未发酵汁则以呈现青草和叶子气味的醛类为主。因而通过酵母菌代谢可明显改善猕猴桃汁的风味。     

Lipoamide dehydrogenase, citrate synthase and beta-hydroxyacyl-CoA-dehydrogenase in skeletal muscle. IX. The influence of the rate of thawing on activity and subcellular distribution in fast and slow frozen bovine muscle

Samples of bovine muscle (post rigor) were frozen at -30 degrees C at two different rates (1.27 min/degrees C and 13.10 min/degrees C) and thawed at different rates between 1.6 (22 degrees C) and 430 min/degrees C (0 degrees C). The activities of the mitochondrial enzymes lipoamide dehydrogenase, citrate synthase, and beta-hydroxyacyl-CoA-dehydrogenase were determined in the supernatant of the tissue homogenate in phosphate buffer (total activity) and in the press juice of the intact tissue (activity in the sarcoplasma). The rate of thawing did not show a significant influence on total enzyme activities. In most cases, however, slow thawing caused a greater release of the enzymes from the mitochondria into the sarcoplasmic fluid than fast thawing, this effect being apparently independent of the rate of freezing. The greater damage to mitochondrial membranes upon slow thawing cannot be due to a longer exposure of the muscle cell to increased ionic strength in the non-freezable part of the cell water at the "critical" temperature around -3 degrees C because freezing of muscle samples at -3 degrees C and incubating them at -3 degrees C for five days resulted neither in changes of the total enzyme activities nor in a release of the three mitochondrial enzymes. From these results it is concluded that the influence of thawing rate on the damage to muscle mitochondria is probably not due to ionic effects or to recrystallization phenomena in the ice phase.     

怀远石榴果汁饮料加工技术研究

以安徽省蚌埠市怀远县出产的石榴为原料,研究石榴果汁饮料的加工技术,确定了工艺流程、产品配方和最佳工艺参数.结果表明:采用浓度为30%的石榴原汁,8%的白砂糖,0.15%的柠檬酸,2.0%的蜂蜜,0.13%Vc,0.10%黄原胶+0.10%CMC,0.05%的山梨酸钾为配方加工出的石榴果汁,风味最佳.最佳工艺参数为Vc打浆前加入,离心速度为4 000 r/min,离心10 min.