响应面法优化酶法制备羊肉特征风味前体工艺

Optimization of Enzymatic Preparation of a Flavor Precursor with Mutton Characteristics by Response Surface Methodology

以精炼羊脂为原料,利用脂肪酶酶解以得到小分子脂解产物。选取底物浓度、加酶量、酶解时间为单因素,脂解率为响应指标进行单因素试验,并在此基础上采用Box-Behnken响应面法设计优化羊脂酶解工艺,且对不同酶解程度羊脂特征性挥发成分进行顶空固相微萃取/气相色谱-质谱(SPME/GC-MS)分析,确定酶解程度与挥发物之间的关系。结果表明,在酶解温度为50℃,pH为6.5时,最佳酶解体系参数为:底物质量分数达到60%,酶添加量为140 U/g底物,酶解时间6 h,脂解率可达29.76%。GC-MS结果表明:在此脂解率时,可富集大量比其它酶解程度更多挥发性的醛类、酮类、酸类、醚类。且在此脂解率时,对香气贡献最大的醛种类最多,总含量最高为(1.868±0.013) ng/g,可作为最适酶解程度。本研究参数为后续羊脂氧化及美拉德反应制备羊肉特征风味香精奠定基础。

Refined mutton was digested by lipases to obtain small molecular products.The substrate concentration,enzyme dosage and enzymatic hydrolysis time were selected as single factors,and the lipolysis rate was used as the response index.The Box-Behnken response surface method was used to optimize the lipolytic process based on the experiment of single factors.The characteristic volatile components with different degree of enzymatic hydrolysis were analyzed by a headspace solid phase microextraction/gas chromatography-mass spectrometry(SPME)/GC-MS),and the relationship between the degree of enzymatic hydrolysis and volatiles was determined.The optimum enzymatic hydrolysis conditions were determined as enzymatic temperature 50℃,pH 6.5,substrate mass fraction 60%,enzyme dosage 140 U/g substrate and hydrolysis time 6 h,under which the lipolysis rate was up to 29.76%.GC-MS analysis showed that with this lipolysis rate,the hydrolyzate was rich in characteristic volatiles such as aldehydes,ketones,acids and ethers,and aldehyde species contributed to the falvor,with the highest total content of 1.868±0.013 ng/g.This study laid the foundation for the subsequent preparation of mutton flavor by oxidation of mutton tallow and Maillard reaction.