【作者】 胡芬；

【导师】 李小定；

【作者基本信息】 华中农业大学 ， 食品科学， 2011， 硕士

【摘要】 淡水鱼作为备受青睐的消费品,其营养价值极为丰富。是优质蛋白质的重要来源,含有人体必需的8种必须氨基酸,不饱和脂肪酸尤其是DHA和EPA。随着人们生活水平的提高,加上消费观念的转变,对淡水鱼类产品的需求也在不断地提高。食品的营养健康、便捷、享受型产品是食品工业发展的新趋势,越来越多的消费者把营养、健康放在了首要位置。目前对于鱼肉品质的研究大多集中在对肉质指标的常规研究上,建立淡水鱼营养价值综合评价体系可以为人们的合理膳食和营养健康提供更合理的指导,为食品的产品开发和加工提供理论依据。本文以湖北地区的淡水鱼为基础,测定了淡水鱼的基本营养指标,建立了几种鱼的营养数据库,并对其营养价值进行比较分析,分析了营养指标随体重的关系；用氨基酸评分、氨基酸多元分析、脂肪酸多元分析的方法对其营养价值进行评价,引入模糊综合评价模型和灰色系统综合评价模型对淡水鱼的营养价值进行综合评价；分析了营养指标与质构指标间的相关性,探讨进一步简化评价过程的可能。(1)测定了4个季节的5～7种淡水鱼的水分、粗蛋白、粗脂肪、粗灰分、脂肪酸、氨基酸等基本营养指标,结果表明淡水鱼营养成分随种类和季节均存在一定差异,粗蛋白含量表现出春冬季高于夏秋季的的现象,而粗脂肪则正好相反,夏秋季要高于春冬季节的粗脂肪含量。氨基酸总含量(占干样)为50%～80%之间,在所测定的17种氨基酸中,Glu、Lys、Ile的含量都较高。EAA总量的变化与氨基酸总量的变化相似,半必需氨基酸随季节及种类的变化不大。共检测到26种脂肪酸,不同鱼类脂肪酸组成有差异,其中棕榈酸(C16：0)、油酸(C18：1n9c)、顺-11-二十烯酸(C20：1)的含量及比例都较高,不饱和脂肪酸含量高于饱和脂肪酸。测定了鲫鱼、草鱼、鲤鱼不同体重下的基本营养指标,所测定3种鱼水分含量随体重的增加而略有降低,粗脂肪随体重的变化差异显著,蛋白质变化与脂肪变化相反,灰分与体重的差异变化不大。氨基酸总量随体重的不同表现出一定的差异,每种氨基酸的差异变化与TAA的变化相似。脂肪酸重量随体重的增加呈增加的趋势,EPA和DHA的总量随体重的增加而降低。(2)对测定的淡水鱼氨基酸进行了氨基酸评价分析,AAS值均接近或大于1,其中Ile和Lys、Phe+ Tyr的AAS值显著高于FAO标准,CS值小于AAS值,Ile和Lys水平较高。(3)分别对所测定淡水鱼的氨基酸和脂肪酸进行了多元分析,氨基酸主成分分析从17种氨基酸中提取出3个主成分因子,累计方差贡献率达86.03%。主成分前的聚类分析将4个季节的5种淡水鱼共分为3类,用3个主成分因子的聚类分析将其分为4类,增大了差异性,但距离较近的鱼类间的距离没有变化,说明主成分后增大了大类的差异性。脂肪酸主成分分析共提取出6个主成分因子,其累计方差贡献率达87.46%,主成分前对4个季节的4种鱼的脂肪酸分为3大类,而主成分因子的聚类分析将其分为了6类,说明鱼类脂肪酸随种类和季节的不同差异较大。以脂肪酸和氨基酸主成分因子为指标的聚类结果与脂肪酸主成分结果较为相似,说明脂肪酸的差异性对鱼类品质的差异有较大的影响。(4)运用了模糊综合评价模型和灰色系统综合评价模型对淡水鱼的营养指标进行了综合评价,根据模糊综合评价结果,综合营养价值最高的是秋季鲢鱼,其次是春季鲫鱼、冬季草鱼、春季团头鲂。灰色聚类结果显示,大部分鱼类都处在中高营养价值区域,因淡水鱼本身就属于高营养价值的食品,符合实际情况。(5)淡水鱼的质构特性随季节和个体表现出显著差异,体重的增加,肌肉硬度增大,弹性增强,春季鱼的质构特性值要大于冬夏两季。质构指标与营养指标和生理指标间均表现一定相关性,硬度、粘聚性和胶着度受营养指标的影响较大。更多还原

【Abstract】 Freshwater fish is famous for rich nutritional value and is very popular in people’s life. It’s the important source of high protein, contains 8 kinds of essential amino acids for human body, and rich in unsaturated fatty acids especially DHA and EPA.With the improvement of living standards, plus the change of consumption idea, the demand for freshwater fishes is increasing constantly. Food’s nutrition and health, convenience is a new trend in the development of food industry for more and more consumers put nutrition, health in the first place. Establishing the comprehensive evaluation system of freshwater nutritional value will guide people’s rational diet and nutrition and health, provide more reasonable guidance for food product development and provide theoretical basis for processing.In this paper, Based on the basis of freshwater fish in Hubei Province, the basic nutrition indexes were measured, nutrient database of freshwater fish was established, the difference of nutritional value among freshwater fish were compared, the relationship between nutritional index and weight was analysed. The amino acid score(AAS), multivariate analysis based on amino acids and fatty acids were used to evaluate the nutrition value of freshwater fish, two comprehensive evaluation models were introduced in this paper,the fuzzy comprehensive evaluation model and the gray system comprehensive evaluation model. The correlation between structure indexes and nutrition indexes was analysed so as to explore several methods to simplify the evaluation process in the future.(1) Nutrition indexes include moisture, crude protein, crude fat, crude ash, fatty acid; amino acids of freshwater fish in four seasons were determined.The results showed that there is variation in nutrients in different freshwater fish species and seasons. The crude protein content in spring and winter is higher than in summer and autumn. But the crude fat content is the opposite of crude protein content while the content in summer and autumn higher than in spring and winter. The proportion of total Amino acid content (of dry kind) is ranged from 50%～80%,17 kinds of amino acid were detected, among them,glutamic acid (Glu), lysine, Ileleucine content is higher. The changes of EAA amount are similar with the total amino acid amount; Semi-EAA amount varies little with season.26 kinds of fatty acids were detected, fatty acid composition varies with different fishes. C16:0, C18:1n9t, C20:1 is with the higher content and ratio, the unsaturated fatty acid content is higher than saturated fatty acid.Basic nutrition indexes of Carassius auratus Linn, Ctenop gharryngodon idellus Cuv.et al, Cyprinus carpio Linn was measured under different weight, the moisture content decreases slightly with body weight, crude fat content vary significantly with weight, and the variation of crude protein content is opposite to crude fat content. Ash content varies little with weight. The total amino acids content varies with weight, the varies of each amino acid is similar with TAA.Fatty acids content increase with weight, but the total EPA and DHA content decrease with weight.(2) According to the ratios and patterns of amino acids recommended by FAO/WHO, the nutritive values of the proteins in freshwater fish were evaluated. The results showed that the amino acid scores (AAS) of 7 kinds of EAA were close to or greater than 1, The AAS of Ileleucine and lysine, phenylalanine + tyrosine are significantly higher than the FAO standards. CS value is less than AAS value, but the CS value of Ile and Lys were close to 1.(3) By applying SPSS, multivariate analysis of amino acids and fatty acids of freshwater fish was given in this paper. Factor analysis was performed for 17 kinds of amino acids of 5 kinds of freshwater fish in four seasons.3 factors were selected whose cumulative contribution of variance accounted to 86.03%.Clustering analysis was adopted to analyze 17 kinds of amino acids of 5 kinds of freshwater fish in four seasons. The 20 kinds of fish were divided into 3 categories while 4 categories were divided Clustering analysis with 3 principal component factors. It seems that the difference between fish groups increased after Factor analysis, but the distance is the same between fish with short distance before Factor analysis.Factor analysis was performed for 26 kinds of fatty acids of 4 kinds of freshwater fish in four seasons.6 factors were selected whose cumulative contribution of variance accounted to 87.46%.Clustering analysis was adopted to analyze these data. Results show that The 16 kinds of fish were divided into 3 categories while 6 categories were divided Clustering analysis with 6 principal component factors. It seems that fatty acids varies significantly with classes and seasons.Clustering analysis was performed for both amino acids and fatty acids, the result was more similar to that of the fatty fish quality. So the comprehensive quality of freshwater fish was greatly affected by fatty acids.(4) Fuzzy comprehensive evaluation model and Gray system comprehensive evaluation model was used in the comprehensive evaluation of freshwater fish. According to fuzzy comprehensive evaluation results, comprehensive nutrition value is the highest in Hypophthalmichthys molitrix Cuv.et al in spring. Grey clustering results showed that most of the freshwater fish were with high nutritional value.(5) TheTPA properties of freshwater fish showed significant differences with seasons and individual. With the weight gain, muscle hardness and springiness increase. TheTPA properties in spring were superior to summer and winter.There were some correlations between the TPA properties and nutrition and physiological indexes which could be seeing in hardeness, adhesiveness, gumminess.更多还原