【作者】 朱健辉；

【导师】 周光宏；

【作者基本信息】 南京农业大学 ， 食品科学， 2005， 硕士

【摘要】 本论文包括三个方面內容:(1)不同等级金华火腿蛋白质水解产物分析;(2)不同等级金华火腿游离脂肪酸分析;(3)不同等级金华火腿挥发性风味物质分析。 第一章:分析了三个等级金华火腿的水分、盐分、pH值、总氮及蛋白水解产物。一级火腿中pH值、总氮显著低于三级火腿(P<0.05),而游离氨基酸态氮占非蛋白氮的比例显著高于二级和三级火腿(P<0.1)。一级和二级火腿的蛋白质水解指数高于三级火腿(P<0.05)。金华火腿中主要的游离氨基酸为Glu、Lys、Ala、Leu、Val,占游离氨基酸总量的47%。一级火腿中各种游离氨基酸含量高于二级和三级火腿,但多数氨基酸差异不显著(P>0.05)。一级火腿氨基酸总量高于三级火腿(P<0.05)。蛋白质水解程度、非蛋白组成、各种游离氨基酸的含量及构成比例,是金华火腿品质差别的一个重要原因。 第二章:分析了三个等级金华火腿肌内脂肪和皮下脂肪中的游离脂肪酸及其氧化情况。金华火腿中主要的游离脂肪酸为棕榈酸、硬脂酸、油酸和亚油酸。肌内脂肪中:肉豆蔻酸、棕榈酸和硬脂酸在一级火腿中的量最高,而三级火腿中亚油酸和花生四烯酸显著高于一级和二级火腿(P<0.05);一级和二级火腿中多不饱和脂肪酸显著低于三级火腿(P<0.05),而饱和及单不饱和脂肪酸差异不显著(P>0.05)。皮下脂肪中:肉豆蔻酸、棕榈酸、硬脂酸、油酸和亚麻酸在一级火腿中的量高于二级和三级火腿(P<0.05);一级火腿中饱和及单不饱和脂肪酸显著高于二级和三级火腿(P<0.05),而多不饱和脂肪酸差异不显著(P>0.05)。一级火腿皮下脂肪的水解作用强于二级和三级火腿,而肌内脂肪的水解程度大于二级火腿。脂肪水解程度是金华火腿品质差异的一个重要原因。 第三章:采用固相微萃取方法并结合气质分析了三个等级金华火腿的挥发性风味物质。鉴定出的主要风味物质为羧酸、酚、醛、醇、酮、酯、内酯、含氮化合物、含硫化合物、芳香烃、脂肪烃等。在不同等级火腿中挥发性化合物的种类相似,但多数化合物的相对含量存在显著差异(P<0.05)。一级火腿挥发性成分中羧酸和醛类物质含量达到60%,其中以乙酸和己醛含量最高,而二级和三级火腿挥发性成分中以丁酸和苯酚为主。羧酸、醛、酮、醇、内酯、含氮化合物、呋喃对金华火腿的风味有促进作用,但过高含量的丁酸和丙酸会有损金华火腿的风味。酯和烃类物质对风味的贡献作用较弱。高含量的苯酚、二甲基二硫化物、二甲基三硫化物和二甲基四硫化物会影响金华火腿的风味。更多还原

【Abstract】 Three parts were included in this paper: (1) The analysis of proteolytic products in Jinhua hams of different quality grade; (2) The amount of free fatty acids in intramuscular and subcutaneous fat was analyzed in Jinhua hams of different quality grade; (3) Volatile flavor compounds were analyzed in Jinhua hams of different quality grade.(1) Moisture, salt, pH, total nitrogen and proteolytic products were analyzed in Jinhua hams of three quality grades. In hams of grade one moisture, pH and total nitrogen were significantly lower than grade three (P<0.05 ), while the ratio of free amino acid nitrogen to non-protein nitrogen was significantly higher than grade two and three (p<0.05) . The proteolysis index of grade one and two was higher than grade three (P<0.1). The major free amino acids in Jinhua hams were glutamic acid、 lysine、 alanine、 leucine and valine, which accounted for 47 per cent of free amino acids . The individual free amino acid in hams of grade one were higher than grade two and three, but most free amino acids differed insignificantly (P>0.05) . The total amount of free amino acids in hams of grade one were higher than grade three (p<0.05) . The degree of proteolysis, component of non-protein nitrogen, amount and proportion of individual free amino acid were one of the important factors to produce different quality in Jinhua hms.(2) The amount of free fatty acids in intramuscular and subcutaneous fat was analyzed in Jinhua hams of three quality grades. The major free fatty acids in Jinhua hams were oleic acid, linoleic acid, palmitic acid, stearic acid. Within intramuscular fat, the amount of myristic acid, stearic acid and linolenic acid in hams of grade one were the most abundant (P<0.05), while linoleic acid and arachidonic acid in hams of grade three were significantly higher than grade one and two (p<0.05). In intramuscular fat of grade one and two hams the polyunsaturated fatty acids were lower than grade three (P<0.05), while saturated and monounsaturated fatty acids differed insignificantly (P>0.05) . Within subcutaneous fat, myristic acid, palmitic acid, stearic acid, oleic acid and linolenic acid in hams of grade one were significant higher than grade two and three (P<0.05). In subcutaneous fat of grade one hams, the saturated and monounsaturated fatty acids were significantly higher than gradetwo and three(.P<0.05), while the polyunsaturated fatty acids differed insignificantly (P>0.05) . The subcutaneous fat in hams of grade one were experienced more intense lipolysis than grade two and three. The lipolytic degree of intramuscular fat in hams of grade one was more intense than grade two. The degree of lipids lipolysis was an important factor to produce different quality in Jinhua hams.(3) The volatile flavor compounds in Jinhua hams of three quality grades were isolated by solid phase microextraction and analyzed by gas chromatography-mass spectrometry. The identified major components were consisted of carboxylic acids, phenols, aldehydes, alcohols, ketones, esters, lactones, nitrogen compounds, sulphur compounds, aliphatic hydrocarbons, aromatic hydrocarbons etc. The volatile substances were similar in hams of different grades, but the relative content of most compounds was differed significantly (P<0.05 ) . In hams of grade one carboxylic acids and aldehydes accounted for 60 per cent of total volatile components, among them the content of acetic acid and hexanal were the most abundant. Butanoic acid and phenol were the major composition of volatile compounds in hams of grade two and three. Carboxylic acids, aldehydes, ketones, alcohols, lactones, nitrogen compounds, furan contributed to the typical aroma of Jinhua hams. But too high content of butamoic acid and propanoic acid damaged the flavor. Esters and hydrocarbons were less important to the flavor. The high content of phenol dimethyl disulfide, dimethyl trisulfide and dimethyl tetrasulfide influenced the aroma. The volatile components contributed, both individually and in combination, to the distinctive aroma properties of Jinhua更多还原