Characterization and Film-Forming Properties of Gelatins from Whitemouth Croaker (Micropogonias furnieri) Skin and Bones

The Whitemouth croaker (Micropogonias furnieri), due to its abundance, is considered one of the most traditional and important species fished in the coastal waters and estuaries of South America. The aim of this work was to produce biopolymeric films of gelatins obtained from skin and bones of Whitemouth croaker. The fish gelatins were characterized through the yield, chemical composition, physiochemical, and rheological properties. The films were characterized by tensile strength (TS), elongation at break (EAB), water vapor permeability (WVP), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), and optical properties. The values of protein yield, hydroxyproline content, gel strength, melting temperature, gelling temperature, and viscosity of the skin gelatin were higher than the values of the bone gelatin. The films obtained of skin gelatin showed all properties and thermal analysis superior in relation to the films of bone gelatin; this can be justified by the best physicochemical and rheological characteristics of the skin gelatin.     

Production of Antioxidative Maillard Reaction Products from Gelatin Hydrolysate of Unicorn Leatherjacket Skin

Antioxidative activities of Maillard reaction products (MRPs) derived from gelatin hydrolysate (GH) of unicorn leatherjacket skin as affected by types of saccharides, GH to saccharide ratio, incubation temperatures, relative humidity (RH), and times were investigated. MRPs prepared using mixture of GH and galactose at 2:1 (w/w) ratio showed the highest antioxidative activity. At different incubation temperatures (50–70°C) and RHs (55–75%), optimal condition for preparing antioxidative MRPs included heating GH and galactose (2:1) powder at 70°C and 55% RH for 36 h. Electrophoresis and Fourier transform infrared spectroscopy revealed the formation of high molecular weight polymers, and the advanced glycation took place in MRPs.     

明胶涂膜保持猪背最长肌冷藏期间新鲜度

与传统的包装材料相比,冷鲜肉的明胶涂膜处理具有众多优势,这也决定其具有广阔的发展前景。为研究明胶涂膜处理对生鲜肉冷藏期间氧化稳定性和新鲜度的影响。该文以猪背最长肌为材料,研究其经过不同浓度(0%、10%、20%)明胶涂膜处理后冷藏期间的加压失水率、脂肪氧化、蛋白质氧化、血红素铁、挥发性盐基氮以及肉色的变化情况。结果表明:猪背最长肌在4℃条件下冷藏第3、5和7 d时,明胶涂膜处理组的硫代巴比妥酸反应值、蛋白质羰基、血红素铁质量分数、挥发性盐基氮值、红度值以及高铁肌红蛋白质量分数分别与对照组比较,结果均存在显著性差异(P0.05)。此外,在冷藏时间相同的条件下,10%与20%明胶涂膜处理组之间均差异不显著(P0.05)。试验证实,明胶涂膜处理有益于提高冷藏期间肉品的氧化稳定性,维系理想的肉品色泽及延长其货架期。     

明胶用量及其与卡拉胶复配对奶冻品质的影响

[目的]奶冻在储存过程中常出现失水现象,为提高奶冻贮藏中的品质和保水性。[方法]以不同时间下奶冻质构特性、持水力、感官品质指标评价奶冻品质,探究明胶添加量以及明胶-卡拉胶复配对奶冻品质的影响。[结果]随明胶添加量增大,水析率、回复性和弹性逐渐减小,硬度和咀嚼度逐渐增大,感官品质先提升后下降,明胶添加量为1.8%时奶冻品质最好;在总胶体用量为1.8%情况下,卡拉胶比例增大,水析率和弹性变化幅度小,硬度先增大后减小再增大,咀嚼度先减小后增大,回复性减小,感官品质先降低后提升最后持续降低,卡拉胶比例为7%时其奶冻品质最好。[结论]1.8%的胶体添加量下添加7%的卡拉胶与明胶复配提高了奶冻的贮藏品质,胶体复配可改善奶冻贮藏中品质下降问题。     

动态高压微射流协同谷氨酰胺转氨酶复合修饰对鱼明胶凝胶特性和结构的影响

为了提高鱼明胶的凝胶特性,本试验采用动态高压微射流(DHPM)协同谷氨酰胺转氨酶(TG)交联(DHPM-TG)技术对鱼明胶进行复合修饰。结果表明,鱼明胶的亮度、特性粘度和胶融温度均随着TG含量的增加而增大,凝胶强度和硬度先增大后减小。与TG修饰技术相比,DHPM-TG复合修饰技术可显著提高鱼明胶的特性粘度、胶融温度、凝胶强度以及胶体的硬度和咀嚼性。此外,环境扫描电镜结果表明,DHPM-TG制备的鱼明胶胶体结构更加致密。综上,DHPM-TG复合修饰显著改善了鱼明胶的凝胶特性,为生产可替代哺乳动物明胶的高品质鱼明胶提供了新的理论依据。     

Comparative Effects of Fish and Cow Gelatins and Locust Bean Gum on Chemical,Textural, and Sensory Properties of Yogurt

ABSTRACT

Yogurt is a traditional dairy product widely consumed all over the world. Syneresis, which is a result of lower water holding capacity, is a big concern and an important quality parameter. In this study, the efficiency of locust bean gum and different gelatins (fish skin, fish scale, and bovine skin) in preventing syneresis was investigated. Samples were stored at 4°C for 2 weeks, a typical shelf life of yogurt, and analyzed periodically for quality parameters. Syneresis, viscosity, and water holding capacity of the control and gum added samples were almost identical, while gelatin added samples were generally significantly improved (p < 0.05).     

Oxidative Stability of Spray-Dried Microencapsulated Fish Oils with Different Wall Materials

Multilayer microencapsulation of fish oil was evaluated by using fish gelatin (treated with or without microbial transglutaminase [MTGase]), chitosan, and maltodextrin for its ability to control lipid oxidation. This study showed that a mixture containing gelatin and maltodextrin obtained the highest percentage of core release. The oxidative stability of the formulated mixtures and the bulk oils was investigated during a period of 60 days. The peroxide value (PV) was assessed as a parameter for primary oxidation products, and p-anisidine (p-AV) and thiobarbituric acid reactive sub-stances (TBARS) was used to analyze secondary oxidation compounds. Observation of oxidation products showed that combinations of gelatin and maltodextrin made by adding MTGase and a mixture of gelatin and chitosan were able to increase the oxidative stability, and increases in PV and p-AV and TBARS were found for all oils.     

河豚鱼皮明胶提取工艺研究

研究从无毒河豚鱼皮下脚料中提取鱼明胶的最佳工艺。考察氢氧化钠浓度、硫酸浓度、预处理时间等因素对明胶提取率及性能的影响，确定最佳前处理工艺为分别以8倍0．2％氢氧化钠水溶液浸泡2h，洗净后以0．3％硫酸水溶液浸泡1h；考察河豚鱼皮明胶提取温度、提取时间、溶剂用量对鱼明胶强度及得率的影响，确定最佳的提取工艺为加4倍量水，在...     

复相乳化法制备明胶微囊蛋氨酸的工艺初探

以明胶和羧甲基纤维素钠为包囊材料,蛋氨酸为芯材采用复相乳化法制备蛋氨酸微胶囊。应用均匀实验设计分析了微胶囊制备过程主要影响因素及适宜的工艺条件,得出明胶溶液浓度对微囊的形成影响较大,优化参数得出蛋氨酸微胶囊载药量为61.30%。