凝固型椰子酸奶品质分析

采用固相微萃取—气相色谱—质谱联用技术(SPME-GC-MS)和高效液相色谱仪(HPLC)分别分析了椰子酸奶发酵前后的香气成分种类及含量的变化以及有机酸含量的变化,并结合物性分析仪和感官分析评价了椰子酸奶的质地品质。结果表明:椰奶经乳酸菌发酵后,香气成分种类增加,椰子酸奶成品中酯类化合物、酸类化合物含量分别降低7.38%,6.88%,醇类化合物、萜烯类化合物、酮类化合物和烷烃类化合物含量分别提高8.14%,0.81%,5.21%,0.13%;椰子酸奶中乳酸含量增加至11.3g/L;得到椰子酸奶质构参数:硬度2.15 N,黏性13.13N·s,内聚性0.317,咀嚼性0.57N;椰子酸奶的糖度为14.8°Brix,酸度为80.47g/L,pH值为4.22,持水力为92.52%。综合以上得出:椰子酸奶凝固较好,酸甜比适宜,持水力较强,同时椰子香味和发酵香气较典型,品质优良。

Analysis of the quality of set-type coconut yogurt

Solid-phase microtraction (SPEM) combined with gas chromatography-mass spectrometry (GC-MS) was employed to analyze the flavor compounds of set-type coconut yogurt. The organic acids were analyzed by high performance liquid chromatography. The quality of coconut yogurt was evaluated by texture analyzer, sensory analysis and physic-chemical analysis. Results showed that the flavor components of coconut milk increased after lactic acid fermentation, the contents of esters and acids in the coconut yogurt decreased by 7.38% and 6.88%, the contents of alchols, terpenes, ketones and alkanes increased by 8.14%, 0.81%, 5.21% and 0.13%, respectively. The content of lactic acid in coconut yogurt increased to 11.3 g/L. The texture parameters of hardness, viscosity, cohesion and chewiness in coconut yogurt were 2.15 N, 13.13 N·s, 0.317 and 0.57 N, respectively. The coconut yogurt had the solid content of 14.8 °Brix, the acidity of 80.47 g/L with pH 4.22, and water holding capacity of 92.52%. In general, the coconut yogurt set well and showed typical coconut flavor and fermentation aroma.