【作者】 曾晓房；

【导师】 赵谋明；

【作者基本信息】 华南理工大学 ， 粮食、油脂及植物蛋白工程， 2007， 博士

【摘要】 鸡骨架是肉鸡加工过程中产生的大宗副产品,但其开发一直没有得到充分重视。本文利用酶解及Maillard反应生香技术对鸡骨架进行深度开发,对于国内鸡骨架的回收利用以及实现鸡肉加工业的可持续发展具有重要意义。鸡骨架富含蛋白质,蛋白质组成氨基酸中必需氨基酸和鲜味氨基酸含量高,抽提物具有良好的呈味效果。采用Pancreatin、Papain、Alcalase、Protamex和Flavorzyme酶解鸡骨架表明,产物中可溶性氮、氨基氮均随酶解时间的延长不断增加,而肽基氮则由于处于生成与降解的动态变化中,存在一最高值。肽谱分析表明,产物中大分子肽段随酶解时间的延长不断减少,而小分子肽段不断增加,不同酶解产物中肽段分子量分布各具特点。复合酶酶解产物中可溶性氮、氨基氮含量以及肽段分子量分布随酶解时间的变化规律与单酶相同。Pancreatin酶解产物中鲜味氨基酸和含硫氨基酸含量较高,适宜于酶解鸡骨架蛋白制备风味基料。在酶解初期以亲水性氨基酸和蛋白酶作用位点氨基酸的释放为主,后期,蛋白酶对肽键的疏水性氨基酸作用加强。鸡骨架酶解过程中氨基酸的释放对产物的呈味具有明显影响,其中以Pancreatin酶解4hr产物呈味效果最好。鸡骨架酶解产物挥发性成分中具有多种对鸡肉风味具有贡献的香味成分,其中以醛类为主,还含有杂环类及含硫直链化合物等,这些物质共同作用构成了鸡骨架酶解产物特有的风味。蛋白酶解、加热灭酶对鸡骨酶解产物挥发性成分的形成具有重要影响,加酶处理能提高鸡骨架的香味贡献成分含量;而加热灭酶使酶解产物鸡肉风味更丰满,能提高鸡骨架挥发性成分中鸡肉香味贡献性成分含量。在最基本配方的基础上,通过Friedman排序检验法确定了以鸡骨架酶解产物为主要原料的Maillard反应制备鸡肉香精的优化条件。在Maillard反应优化条件下,反应过程中呈鲜味的天冬氨酸、谷氨酸损失较少,因此,Maillard反应制备鸡肉香精对体系的鲜味强度影响程度较小。经GC-MS检测显示,共检出产物包括:烃类12种、醇类13种、醛类16种、酮类4种、酸类3种、酯类2种、杂环类22种以及含硫直链化合物2种共计74种,其中醛类、醇类、杂环类较多,三者占定性化合物总量的78.51%。鸡骨架酶解肽中疏水性氨基酸在Maillard反应中的降解程度较大,而亲水性氨基酸在热降解过程中的降解程度较大。鸡骨架酶解肽的降解与酶解程度有关,而且与肽段分子量具有相关性。鸡骨架酶解肽与葡萄糖Maillard反应所产生的挥发性产物以含氮杂环化合物最多,其中吡嗪类化合物占定性化合物的34.04%。更多还原

【Abstract】 Chicken bone is one of staple byproducts of poultry-processing. However, chicken bone has not been pay much attention to recycle, and the bulk of this material is being either discarded or partly used. Hence, further development of this material using bio-enzymatic and Maillard enhancing aroma reaction techniques in this thesis means much for improving this situation and facilitating sustainable development of poultry-processing industry.The composition of chicken bone showed it had high content of protein, and the ratio of constituent amino acid indicated that chicken protein had high content of necessary amino acids, umami amino acids, and what’s more, had a good taste in its extraction solution. Five Proteases (Pancreatin, Papain, Alcalase, Protamex, Flavorzyme) were employed to hydrolyze chicken bone. The content of soluble nitrogen, amino nitrogen were obviously increased after treated by protease and the content of them was increased as the hydrolysis time increased. The result obtained from SEC profile of different hydrolysate showed that higher molecular weigh fractions in peptide decreased and smaller one in peptide increased as hydrolysis time increased. This suggested that the molecular weight distribution profile and functional properties of hydrolysates could be controlled by using relevant protease.During chicken bone treated by Pancreatin, almost all free amino acid content increased as hydrolysis time prolonged, in which hydrophilic amino acids and amino acids in main cleavage site of Pancreatin were preferred to liberate. In initial stage of chicken bone treated by pancreatin, hydrophilic amino acid was liberated more preferablely than hydrophobic amino acid, the mole ratio of hydrophilic amino acid, However, when extensively hydrolyzed, more and more hydrophobic amino acid was liberated from peptide bonds due to treated by Pancreatin. The amino acid liberation rule during chicken bone treated by protease caused important effect on qualities of hydrolysates, and the 4 hr hydrolysates of Pancreatin had best savory characteristics.The volatile compounds in chicken bone hydrolysates was rich and owned highest content of aldehyde, including some important chicken charateristics flavor compounds. The results of volatile compounds in flavor concentration of chicken bone hydrolysates with and without protease treatment showed that lever of volatiles were influenced obviously by protease treatment and protease treatment was help for strengthening chicken characteristic flavor. Meanwhile, thermal inactivation procedure would improve the lipid aroma, meat flavor and the whole flavor quality of chicken bone hydrolysate. The conditions for Maillard reaction to produce chicken process flavorings optimized by the Friedman methodology. The GC-MS results of chicken flavor showned that, aldehydes, alcohols and heterocyclyclic compounds were the major volatile compounds and accounted for 78.51% in all volatile compouns, thus, the chicken flavor was good in chicken characteristic flavor and meat flavor when prepared on the base of chicken bone hydrolysates.The degradation peptide fractions in chicken bone hydrolysate during Maillard reaction showed that it was related with hydrolysis degree of chicken bone hydrolysates and molecular weight of peptide fractions. The length of peptide fractions was responsible for influencing the peptide fraction degradation in Maillard reaction. The results of component amino acid in chicken bone hydrolysate peptide showed that hydrophilic amino acid had a higher degradation degree in thermal degradation reaction and a milder degradation degree in Maillard reaction when compare to hydrophobic amino acids. The GC-MS analysis of chicken bone hydrolysate peptide fractions Maillard reaction with glucose showed that nitrogen-containing heterocyclyclic compounds was the dominating component in volatile compounds, among which pyrazines were major compounds and pyrazines accounted for 34.04% in all identified compounds.更多还原