卡拉胶在香肠中的应用

<正> 卡拉胶萃取自红海藻,是一种长链多糖,即所谓的牛聚乳糖,不能被人体吸收,已获得欧盟承认为一种无害的食品添加剂,在食品工业中主要被用作稳定剂和增稠剂,也是肉制品的理想油脂替代品。本文将探讨其特性及其在香肠加工中的应用。 卡拉胶的性质 高持水和保水性 卡拉胶具有非常高的蛋白反应性,故与高蛋白含量的肉类混合时,就会与蛋白质和水分结合(包括肉类本身水分和外来水),形成不可逆转的网络结构。由于只有键合的水分子才能保存于产品中,这个网络结构的形成就使产品更加多汁。     

卡拉胶及其在香肠制品中的应用

卡拉胶是源于某些红藻的天然硫酸多糖,具有多种生物活性。本文主要介绍了卡拉胶的来源、结构、类型及其在香肠制品中的应用。     

卡拉胶凝胶特性及其在巧克力牛奶中的应用

针对卡拉胶水凝胶的两个主要指标凝胶强度和胶体黏度,研究了卡拉胶含量、钾离子浓度和pH值三个主要因素对卡拉胶水凝胶特性的影响,结果表明:凝胶强度随胶体含量的增加线性增大后渐趋平稳、受钾离子的影响出现峰值、在pH值8.0和10处出现两个拐点;胶液黏度随卡拉胶含量增加迅速增大、随钾离子浓度提高而减小、中性时的黏度最大.通过正交实验确定了影响卡拉胶凝胶因素的主次顺序为卡拉胶浓度、钾离子浓度和溶液的pH值,最佳条件组合为卡拉胶浓度1.2%,钾离子浓度1.2%,pH值9.0;通过考察单独使用卡拉胶以及卡拉胶与魔芋胶、刺槐豆胶及结冷胶等几种食品胶在巧克力牛奶中形成凝胶时的结构状态,判定卡拉胶与刺槐豆胶的协同作用效果最佳.     

κ-卡拉胶在共溶质场中的凝胶形成机制及在3D打印中的应用进展

κ-卡拉胶因其优异的胶凝能力而被广泛用于食品行业中。共溶质场是指蛋白或多糖等高分子材料溶胶-凝胶转变时所处的环境不是仅含高分子组分的水溶液环境,同时溶液中还含有蔗糖、乳化剂、多元醇等单一或多种小分子共溶物（即共溶质）。共溶质对κ-卡拉胶的凝胶化进程有重要影响,其相关作用机制包含以下三种假说：共溶质引起“水的结构化”、高分子对共溶质的“排离效应”、共溶质与高分子的“结合效应”,但目前尚没有统一的结论。此外,本文还综述了κ-卡拉胶在3D打印食品中的应用,包括κ-卡拉胶作为3D打印用凝胶基质材料、以及κ-卡拉胶作为添加剂以调控不同食材体系的3D打印特性。     

k－卡拉胶凝胶特性的研究

本文研究了卡拉胶含量、钾离子浓度、凝胶温度和pH值对卡拉胶水凝胶的强度和粘度的影响。结果表明:胶体含量是影响凝胶强度和粘度的主要因素,凝胶强度随胶体含量的增加线性提高后渐趋平稳、受钾离子的影响出现峰值、在pH值8.0和10.0处出现两个拐点;胶液粘度随卡拉胶含量增加迅速增大、随钾离子浓度提高而减小,中性时的粘度最大。     

卡拉胶及其在香肠制品中的应用

卡拉胶是源于某些红藻的天然硫酸多糖,具有多种生物活性。本文主要介绍了卡拉胶的来源、结构、类型及基在香肠制品中的应用。     

对卡拉胶及其魔芋复配凝胶强度的测量

本文对卡拉胶及其与魔芋复配胶,在不同的ＫＣｌ浓度,不同ｐＨ环境,不同酸化浓度,不同温度下加酸所成凝胶,以及凝胶在不同温度和不同测量时间内的胶凝强度进行了测量。９并对观察所得结果进行了初步的解释,探讨和推测。     

卡拉胶凝胶质构特性的研究

研究了卡拉胶凝胶的质构特性。结果表明,影响卡拉胶凝胶硬度的主次因素依次为:〔K+〕、离子强度、〔Ca2+〕、卡拉胶浓度、pH、〔Mg2+〕;影响其弹性的因素依次为:〔K+〕、离子强度、卡拉胶浓度、〔Ca2+〕、pH、〔Mg2+〕。形成较好凝胶的条件为:卡拉胶浓度10～20mg/mL、pH5、离子强度0.3、〔K+〕0.05mol/L、〔Ca2+〕0.025～0.05mol/L。在肌原纤维蛋白中添加卡拉胶能明显增加凝胶的硬度、弹性和保水性。      

壳聚糖明胶共混成纤的研究

明胶是温水可溶的多肽高分子聚合物，含有人体所必需的多种氨基酸；壳聚糖是天然甲壳素经乙酰基反应后的可溶物，具有良好的生物相容性和防腐抑茵性。根据明胶和壳聚糖的用途及优良性能，通过系列实验筛选出明胶与壳聚糖共混成纤的条件及工艺路线。     

十二烷基硫酸钠和乙醇对明胶超细纤维成型的影响

通过添加表面活性剂十二烷基硫酸钠(SDS)、乙醇改善较低质量分数(13%)明胶水溶液的静电纺丝成型性能,发现SDS在降低明胶溶液表面张力的同时,提高了溶液的电导率及黏度。当SDS质量分数在0.5%以上时,电纺明胶纤维毡中的串珠消失;溶剂中水/乙醇为95/5(质量比)时,获得的明胶超细纤维毡中串珠减少且纤维直径变细。     

Physico-chemical and film forming properties of giant squid (Dosidicus gigas) gelatin

Giant squid (Dosidicus gigas) inner and outer tunics were subjected to hydrolysis with pepsin prior to gelatin extraction (G1 gelatin) by a mild-acid procedure. Furthermore, a second gelatin extraction (G2 gelatin) was done using the collagenous residues that remained from the first extraction. Pepsin allows the collagen solubilisation and the extraction yield to increase by yielding extracts high in α-chains. G1 exhibited good gel forming ability but G2 showed poor viscoelastic behaviour and low gel strength, in agreement with the results for the molecular weight distribution, which showed a considerably higher content of low molecular weight components. In spite of these differences, both G1 and G2 showed good filmogenic ability and similar properties were found including the absence of colour, opacity, low water vapour permeability and high puncture deformation. Nevertheless, films made from G1 had a higher puncture force than films made from G2 as a result of the different molecular weight distribution.     

明胶在锂离子电池正极制备中的应用

采用明胶溶液对锂离子电池正极中导电剂石墨的分布进行优化,在最终的正极复合物中石墨的含量仅为2.1%.经明胶溶液优化后,石墨粒子在LiMn2O4颗粒表面上分布较均匀,而且在明胶的固化作用下,石墨粒子与LiMn2O4的相对位置被固定下来,从而使得石墨粒子传导电子的能力增强,传导电子的路径更加稳定,锂离子也更容易在活性颗粒表面嵌入和脱出,大大提高了正极材料的循环性能.     

明胶微球的制备及其粒径影响因素的研究

以明胶为原料,采用乳化交联法制备明胶微球;分别考察了搅拌速度、乳化剂用量、明胶浓度、水油相比例和乳化时间对明胶微球(GMS)质量和粒径的影响;选取其中影响较为显著的搅拌速度、明胶浓度、水油相比例3个因素为考察对象,进行正交优化实验。结果表明,提高搅拌速率、降低明胶浓度或水油比例均有利于减小GMS的粒径并提高其圆整度;通过优化实验条件,在明胶浓度0.20g/mL、搅拌速度800r/min、水油比1∶6、1.5%的乳化剂用量、乳化15min时研制出了平均粒径为11.6μm的表面平整、分散性好的GMS。     

不同干燥方式对明胶特性的影响

系统研究了不同干燥方式(热风干燥,真空冷冻干燥和喷雾干燥)对明胶性质的影响,包括得率、色差、十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(sodium dodecyl sulfate-polyacrylamide gel electrophoresis,SDS-PAGE)、凝胶强度、凝胶持水力、疏水性以及傅里叶变换红外光谱(Fo...     

Mass spectrometric detection of marker peptides in tryptic digests of gelatin: A new method to differentiate between bovine and porcine gelatin

Gelatin is a mixture of polypeptides obtained by hydrolysis of collagen primarily from bovine and porcine skin and bones. The similarity between different gelatins makes it difficult to trace their species origin. In this work, a new method for differentiation between bovine and porcine gelatin was developed based on detection and identification of marker peptides in digested gelatins. Sequence alignment analysis indicates that bovine and porcine Type I collagen contain differential sequences. The gelatins were digested by trypsin, and the resulting peptides were analyzed by high performance liquid chromatography/tandem mass spectrometry (HPLC–MS/MS). The marker peptides specific for bovine and porcine were successfully detected in the digested bovine and porcine gelatin, respectively. Comparative analysis indicated that more marker peptides could be detected in gelatin with a higher mean molecular weight. It was found that proline hydroxylation was a key factor affecting the peptide identification. For peptides such as GPPGSAGSPGK and GPPGSAGAPGK detected in digested bovine and porcine gelatin, respectively, the sequence should be verified manually since the mass shift caused by proline hydroxylation can be confused with the mass difference between Ser and Ala residues. The results indicate that detection of marker peptides in the digested gelatin sample using HPLC–MS/MS is an effective method to differentiate between bovine and porcine gelatin.     

Optimising conditions for enzymatic extraction of edible gelatin from the cattle bones using response surface methodology

This work was initiated to optimise the factors affecting the enzymatic extraction of edible gelatin from the cattle bones using response surface methodology. A central composite rotatable design was used to evaluate the effects of the enzyme concentration, time of enzymatic treatment and extraction temperature on the yield of extraction, gel strength, apparent viscosity and absorption at 420 nm. The R ² values of regression models for all the response variables were higher than 0.9. Data analysis showed that all the process variables significantly ( P  < 0.01) affected the gel strength and apparent viscosity of extracted gelatin, whereas the effect of extraction temperature on both yield of extraction and absorption at 420 nm was not significant ( P  > 0.05). Graphical optimum conditions for the extraction yield, gel strength, apparent viscosity and absorption at 420 nm were determined as 6.1 ppm, 15.6 h, 70 °C; 9.1 ppm, 11.9 h, 70.3 °C; 7.86 ppm, 14.9 h, 77.5 °C and 2.8 ppm, 10 h, 60 °C, respectively. For all the response variables, the experimental values were very close to the predicted values and were not statistically different ( P  < 0.05).     

干发酵香肠中发酵剂活化条件的研究

本文研究了发酵香肠中发酵剂的活化条件,主要考察活化温度、活化时间和培养基添加量对香肠产酸能力的影响.结果表明,活化温度和活化时间对香肠产酸能力的影响显著(p＜0.05);而培养基添加量对香肠的产酸能力影响不显著,添加量超过80mL/kg时,香肠的感官品质迅速下降.当活化温度从22℃升至33℃时,发酵剂产酸能力随之增强;温度继续升高,产酸能力逐渐降低.而在39h时,香肠的pH随活化时间的增加显著下降,9h时降至5.27,活化时间延长至15h,pH基本趋于稳定.将发酵剂接种于脱脂牛乳中,培养基添加量为40mL/kg,32℃下培养12h,香肠的产酸能力最强,感官品质较好.另外,本试验中最佳活化条件生产的香肠中亚硝酸盐残留量为9.1mg/kg,符合国家肠制品对亚硝酸盐残留量的规定,香肠的安全性较高.     

Evaluation of tilapia skin gelatin as a mammalian gelatin replacer in acid milk gels and low-fat stirred yogurt

Tilapia skin gelatin (TSG) was studied in a 3-stage process (cooling, annealing, and heating) for pure gelatin gels and in a 4-stage process (acidification, cooling, annealing, and heating) for acid milk gels and cultured yogurt. The aim was to evaluate the use of TSG as a replacement for mammalian gelatin in yogurt. In pure TSG gels, stronger gels with higher melting temperatures were formed with increasing TSG concentrations. Compared with bovine gelatin (BG), which gelled at a concentration of 2.5%, TSG gels had lower gelling (14.1°C) and melting (24°C) temperatures but comparable storage moduli during annealing. In acid milk gels, addition of TSG increased the firmness of the gels with increasing concentration. Gelling and melting points of TSG in milk gels were observed at sufficient concentrations during cooling and heating. Strands and sheets were observed in the electron micrographs of milk gels with 1% TSG and a very dense structure was observed with 2.5% TSG. Yogurt with 0.4% TSG had similar viscosity, consistency, pseudoplasticity, and thixotropy as yogurt containing 0.4% BG; no difference was perceived by sensory panelists according to a triangle test. Addition of 0.4% TSG completely prevented whey separation from the acid milk gel and yogurt. The results suggest that TSG could be a suitable replacement for mammalian gelatin in low-fat stirred yogurt.