混浊枇杷汁的配料和加工工序研究

为了制备稳定的混浊枇杷汁产品,通过正交实验研究了不同因素(枇杷果肉含量、糖含量、加酸量、稳定剂加量)对混浊枇杷汁稳定性的影响,并通过常规静置观察的方法,探讨了制备稳定的混浊枇杷汁的最佳工艺条件.结果表明,影响混浊枇杷汁稳定性的主次因素依次为:加酸量＞糖含量＞稳定剂加量＞枇杷果肉含量:制备稳定混浊枇杷汁的最佳因素组合为:枇杷果肉20%,糖含量7.6%,加酸量0.35%,稳定剂(黄原胶:CMC-Na=1:1)加量0.10%;杀菌前的可以离心工序提高产品的稳定性.     

果浆酶Pectinex SMASH澄清香蕉汁的机理

探讨了PectinexSMASH澄清香蕉汁的机理。研究表明,香蕉汁悬浮颗粒主要是由蛋白质与碳水化合物组成,在酸性条件下,带正电荷的蛋白质被带负电荷的果胶包裹形成稳定的混浊体系。澄清前悬浮颗粒的平均粒径为0236μm,属于胶体分散体系,果汁混浊。经PectinexSMASH处理后,悬浮颗粒中果胶被降解从而聚合度降低,悬浮颗粒中带正电荷的蛋白质暴露出来,颗粒Zeta电位降低。带不同电荷的颗粒相互吸引聚集增大,澄清60min时颗粒平均粒径为16986μm,属于不稳定的粗分散体系而容易发生凝沉。通过透射电镜观察发现,香蕉汁悬浮颗粒在澄清前彼此分散且粒径小,澄清后颗粒通过网络结构形成交联聚集体,香蕉汁因悬浮颗粒聚集凝沉而澄清,证实了前人提出的果胶酶澄清果汁的模型。     

不同稳定剂对混浊百合汁稳定性作用的研究

本文研究了三种选定的稳定剂(海藻酸钠、卡拉胶和黄原胶)对混浊百合汁稳定性的影响。结果表明,海藻酸钠对百合汁的稳定作用比卡拉胶和黄原胶更好。使用稳定剂,尤其是海藻酸钠,能够延长百合汁的货架期,同时,还能提高百合汁的浊度、粘度和混浊稳定性。     

均质工艺对苹果浊汁品质的影响

利用不同均质压力(0、10、20、30和40MPa)、均质次数对苹果浊汁进行均质,研究均质工艺对苹果浊汁的褐变情况、悬浮稳定性的影响,还对果汁中果肉颗粒的大小、果汁粘度这两个影响果汁悬浮稳定性的因素进行了探讨。实验结果表明,在30MPa下均质一次可以得到最理想的苹果浊汁。     

不同的亲水胶体对银杏浊汁稳定性的影响

将不同的亲水胶体添加于银杏浊汁中,结果发现高酯果胶、瓜儿豆胶和亚麻籽胶对银杏浊汁的稳定效果较好。对分别加入这3种胶体的银杏浊汁进行储藏稳定性研究,结果表明:0.05%(w/v)的亚麻籽胶对银杏浊汁在储藏期间保持混浊稳定性的效果最好。银杏浊汁的混浊稳定性要依靠悬浮颗粒间的静电排斥作用,更主要的是依靠亲水胶体增稠所提高的大分子空间排斥作用。     

桑果汁稳定性研究

以桑椹榨汁后的桑果浆为原料,经调配、均质、杀菌等处 理,研制桑果浑汁饮料,对桑果浑汁饮料的果浆含量、糖 酸比、稳定剂的选用、均质条件及杀菌条件对产品稳定性 的影响进行了探讨。实验结果表明,果浆含量35％,加糖 量12％,糖酸比40:1时桑果汁风味最佳;以0.10％黄原胶 与0.15％酸性CMC复合稳定剂对产品的稳定效果最好: 调配液在40℃下均质10min,可显著提高产品稳定性:采 用121℃,10s高温瞬时杀菌效果最好,对成品风味和稳定 性影响最小。     

加工工艺对脱脂发酵乳饮料酪蛋白颗粒粒径和稳定性的影响

介绍了脱脂发酵乳饮料生产工艺中发酵条件（温度）、菌种、发酵奶均质、稳定剂对产品酪蛋白颗粒粒径大小和稳定性的影响。结果表明，MA14菌种、低温35℃长时间发酵、发酵奶均质、选择高甲氧基果胶做稳定剂均能够降低发酵乳饮料的酪蛋白颗粒粒径和离心沉淀率．提高产品的稳定性。     

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.     

甜玉米浊汁饮料加工技术

研究了甜玉米浊汁饮料的加工技术,提出了影响其稳定性的关键点控制的具体工艺要求,从而得出了保持其浊汁稳定的最佳生产工艺条件为:添加0.1%乳化稳定剂、控制粒度20μm,在70℃、20～30MPa压力下进行两次均质.     

柑桔汁沉淀与果胶酯酶的关系

现代加工的桔汁都呈混浊状态,混浊物质主要是由不溶性的直径在10微米以下的微细颗粒组成,它们含有大量的色素、风味及营养成分,是柑桔汁色、香、味、体的重要组成部分。但若不进行混浊稳定化处理,混浊物质就会在贮运过程中,以凝絮状态析出,产生清液层,从而失去了柑桔汁应有的鲜艳色泽和混浊状态。这种现象主要是由于果胶酯酶的存在,破坏了胶体的稳定性所引起的。一、果胶酯酶的特性现已发现果胶酯酶有12种单体,因对热的稳定性不同,而分为热敏单体和热稳单体两     

Physico-chemical characteristics of orange juice cloud

Orange juice is a suspension of heterogeneous particles in a clear serum. The size of the particles varies between 0·05 μm and a few hundred μm. The particles with a size below 2 μm constitute the stable ‘cloud’. This fraction consists of needle-like crystals of hesperidin, chromoplastids, amorphous (rag) particles and oil globules attached to some of these particles. The adsorption of oil globules on the rag particles enhances their stability in suspension, by decreasing their density. The hesperidin crystals are formed partly by crystallisation immediately after juice extraction. All the cloud particles exhibit a negative charge, which decreases with decreasing pH. However, it seems that hydration rather than electrical charge is responsible for the stabilisation of the cloud. Heat treatment of the juice causes an increase in the number of fine particles at the expense of coarser ones. In this process some extraction of pectin into the serum also takes place but this has little significance on the cloudiness and cloud stability of the juice.     

Stable Clouding Agent from Isolated Soy Protein

In a dilute suspension the stability of soy protein particles equalled or surpassed that of orange juice prepared from concentrate during short-term storage at 4°C. Soluble soy protein produced a stable cloud only when soluble pectin was present in the incubation medium as the particles were forming. In the absence of soluble pectin the nascent soy protein particles rapidly aggregated. This soy protein based clouding agent may provide a natural and healthy alternative to oil-derived clouding agents. The stabilization of such suspended soy protein particles also provides a model system that may be comparable to orange juice cloud for stability studies.     

破碎时蒸汽热处理对浑浊苹果汁色泽及浑浊稳定性的影响

苹果破碎时 ,蒸汽热处理使果浆温度在 80s内达 92℃以上 ,不但改善了浑浊苹果汁色泽且可增强果汁的浑浊稳定性。果汁的颜色明显受果浆所达到的最高温度影响。苹果浆温度达92℃和 95℃虽然VC 损失较多 ,但如果果汁的总酚损失较小 ,则有好的色泽稳定性。苹果破碎过程中发生的褐变主要为酶促褐变 ,但热处理温度高于 98℃ ,非酶褐变会变得显著。果汁的混浊稳定性受果汁中悬浮颗粒的大小、果汁的粘度影响。热处理增加了果胶的聚合度 ,促进果胶从果浆中的释放 ,从而增加了果汁的粘度。热还处理可减小果汁中悬浮颗浊的大小。     

橙汁混浊的稳定性

研究成熟度、制汁工艺、酶处理、贮藏条件对橙汁混浊稳定性影响。结果表明：随着成熟度增加,橙汁混浊度呈上升趋势;胶体磨细微化可以增加果浆中果胶、可溶性果胶的溶出,果胶含量显著增加(P ＜ 0.05);果胶酯酶(PE)活性影响橙汁混浊稳定性,应完全钝化;采用果胶酶酶解会破坏橙汁浑浊稳定性,木瓜蛋白酶酶解橙汁浑浊度的影响不明显;4℃和15℃贮藏对橙汁混浊度的影响不显著(P ＞ 0.05),25℃贮藏对橙汁混浊度降低影响显著(P ＜ 0.05),常温贮藏不利于保持橙汁混浊稳定性。     

怀菊花红枣乳酸菌饮料的工艺及稳定性研究

以发酵酸奶为主要原料,复配怀菊花汁和红枣浓缩汁制作一种具有清热祛火、补气养血、抗氧化的乳酸菌饮料。主要探讨了产品的感官质量和稳定性。通过正交试验,确定了怀菊花红枣乳酸菌饮料调配的最佳配方和适宜的制作工艺流程;同时研究了复配稳定剂对乳酸菌饮料稳定性的影响。试验结果表明,分别添加30%发酵酸奶、7%怀菊花汁、2%红枣浓缩汁、8%蔗糖、0.4%稳定剂制作的怀菊花红枣乳酸菌饮料具有较好的口感和稳定性。     

Sedimentation behaviour and turbidity of carrot juices in relation to the characteristics of their cloud particles

The cloud stability of carrot juices was investigated using physical methods. In contrast to cloudy juices from fruits or other vegetables described so far, complete clarification of juice samples could not be achieved even after ultracentrifugation. Since the density of one particle fraction was almost equal to that of the continuous phase, this fraction was resistant to sedimentation by centrifugal forces up to 60 600 × g in an 8° Brix carrot juice. Cloud stability problems of carrot juices, therefore, are usually associated with bottom sediment formation, but not with visible loss of turbidity. Particle size and density were shown to be decisive for suspension stability, whilst both particle charge and serum viscosity did not show any effect on cloud stability. The reasons for the exceptional stability of the suspended particles are discussed. Based on three particle fractions, a new physical concept could be deduced according to particle size and density explaining the extraordinary suspension stability of carrot juices. Copyright © 2003 Society of Chemical Industry     

基于空间-时间消光图谱技术测定不同稳定剂对西番莲果汁稳定性的影响

为了解决西番莲果汁稳定性差、易沉淀的问题,本研究以西番莲果汁为研究对象,使用基于空间-时间消光图谱技术的全自动稳定性分析仪以沉降速率、积分透射率和透射红外图谱为主要分析指标,判定稳定剂琼脂、羧甲基纤维素钠及这两种稳定剂复配对西番莲果汁稳定性的影响,选出相对适宜的单一稳定剂以及复配稳定剂的添加比例.结果表明:添加单一稳定...     

沙棘果汁稳定剂选择初探

目的：选择合适的沙刺果汁稳定剂,以保持沙棘果汁的稳定性。方法：通过单因素试验对沙棘果汁稳定剂的选用进行了探讨。结果：沙棘果汁饮料的最佳乳化稳定剂为黄原胶,添加量为0.2%,羧甲基纤维素钠（CMC-Na）和单甘酯的稳定效果均不理想。结论：工艺简单可行,成本低廉,具有很好的市场开发前景。     

混浊胡萝卜橙汁生产中稳定性的研究

研究了七种单一稳定剂对胡萝卜橙汁稳定性的影响,并从中选择了三种稳定剂进行复合,研究其稳定性。结果表明,黄原胶、瓜儿豆胶和海藻酸钠对原料的稳定性较其它几种更好。将这三种进行复合,结果表明黄原胶:瓜儿豆胶:海藻酸钠按3:1:1的比例,添加量为0．12％,使胡萝卜橙汁达到很好的稳定效果。     

Calcium and pH influence on orange juice cloud stability

BACKGROUND: Clarification of citrus juice is a severe quality defect related to pectin methylesterase (PME) activity. PME activity and calcium chelation of pectic acid as well as other physical interactions of cloud components influence cloud stability. The cloud stability and physical properties of pulp‐free, fresh juice with and without ammonium oxalate (AO) at pH 4.0 and pH 5.5 was evaluated. RESULTS: The only juice to clarify in the 3‐week study was the sample without AO at pH 4.0. Particle size analysis showed that the samples at pH 4.0 were larger than those at pH 5.5, and samples at pH 5.5 had a more negative zeta potential than samples at pH 4.0. Furthermore, cloud particle size increased and then decreased prior to the onset of clarification. CONCLUSION: Ammonium oxalate prevented sedimentation via calcium pectate cross‐bridges and subsequent clarification. Interaction of cloud constituents, change in particle size with pH and change in particle size with storage time suggest that, in addition to electrostatic attraction and calcium binding, cloud particles associate and dissociate via non‐covalent, non‐electrostatic interactions. Copyright © 2010 Society of Chemical Industry