鸡肉酶解物中不同氨基前体对肉香味形成的贡献

通过超滤分离鸡肉酶解物,制备分子质量小于1 ku、1~5 ku、大于5 ku的3个肽组分样品。采用盐酸水解鸡肉酶解物,制备氨基酸组分样品。以3个肽组分和氨基酸组分及葡萄糖为原料,设计加或不加氧化鸡脂两类共8个模型反应体系,研究鸡肉酶解物中不同氨基组分对肉香味形成的贡献。通过分析比较反应产物在波长420 nm处紫外-可见光吸收值和pH变化值,以及固相微萃取/气-质联机分析挥发性风味物质组成,发现对于加与不加氧化鸡脂的两类反应体系,均为随氨基组分的分子质量增大,420 nm处紫外-可见光吸收值降低,产生的挥发性化合物总量减少,这可能因分子质量大反应活性差导致。无论加或不加氧化鸡脂,均为氨基酸组分对含硫化合物贡献最大,小于1 ku和1~5 ku肽组分对吡嗪类化合物贡献最大。但氧化鸡脂中含有羰基类脂质氧化产物可对美拉德反应有影响,与不加氧化鸡脂相比,加入氧化鸡脂后420 nm处紫外-可见光吸收值稍增加,产生的风味化合物总量大幅度下降,并有带烷基链的化合物(如2-甲基-5-丙基-噻吩)含量增加及新杂环化合物2-丁基吡啶出现。

Roles of Different Amino-containing Precursors in Enzymatically Hydrolyzed Chicken in Meat Flavor Formation

To study the effect of different amino-containing precursors to meat flavor formation,peptides fractions in molecular weights of<1 ku,1-5 ku,and>5 ku,were separated from enzymatically hydrolyzed chicken by ultrafiltration,and the samples of free amino acids were prepared by hydrochloric acid hydrolysis of the enzymatically hydrolyzed chicken.A total of eight model thermal reactions subdivided into two types,i.e.,with or without the addition of oxidized chicken fat,were carried out using the samples of peptide fractions and the free amino acids,and glucose as reactants.For the reaction products,the absorbance at 420 nm and pH values were measured,and the volatile flavor compounds were analyzed by solid phase microextraction(SPME)and gas chromatography-mass spectrometry(GC-MS).It showed that for both the two types of reactions,with the increase of molecular weight of the amino-containing samples,absorbance values at 420 nm and total amounts of volatile compounds were decreased.These might be due to the amino-containing precursors of larger molecular weights from the enzymatically hydrolyzed chicken possessing a lower reactivity.Among them,the free amino acid samples behaved the best in generation of sulfur-containing compounds,and the<1ku or 1-5 ku peptides samples behaved the best in generation of pyrazine compounds.On the other hand,because of affect of lipid degradation products especially carbonyls in the oxidized chicken fat on the Maillard reaction,when the oxidized chicken fat was added,absorbance values at 420 nm of the reaction solutions were slightly increased,whereas total amounts of volatile flavor compounds were considerably decreased.Meanwhile,amounts of some alkane chain compounds(e.g.2-methyl-5-propylthiophene)were increased and a new alkane chain compound 2-butylpyridine emerged with the addition of the oxidized chicken fat.