Optimization of the Extraction Technique of Free Amino Acids from Pixian Board-bean Paste by Response Surface Methodology and Analysis of Their Taste Characteristics

The extraction technology of free amino acids from Pixian board-bean paste was optimized and its taste characteristics were studied in this paper. On the basis of single factor test and taking free amino acids extraction amount as an indicator,the amino acid extraction process was optimized using response surface test,and free amino acids of six kinds of Pixian board-bean paste were analyzed by amino acid automatic analyzer. The taste active compounds and their contribution were evaluated by taste activity value(TAV),and taste characteristics of Pixian board-bean paste were determinded by taste sensory evaluation. As a result,optimum extraction process parameters of free amino acids in Pixian broad-bean paste were obtained:Liquid material ratio 27:1 (mL/g),ultrasonic temperature 35℃,and ultrasonic time 30 min,the extraction rate amount of free amino acids was 18.51 mg/g.Umami with sour taste free amino acids(glutamic acid(Glu),aspartic acid(Asp)and asparagine(Asn))were the most abundant,the average content was 6.380 mg/g in six kinds of Pixian board-bean paste,followed by umami and sweet taste of free amino acids(threonine(Thr),serine(Ser),glycine(Gly),alanine(Ala)and proline(Pro)),the average content was found to be 5.540 mg/g,in addition,the amount of bitter taste and bitter with sweet taste amino acids were least,the results showed that average content of umami taste free amino acids was 11.920 mg/g.The value of glycine,glutamic acid,aspartic acid,lysine,hlstidine,argnine and valine showed TAV>1,they were the major contributors to the taste of Pixian board-bean paste.The taste sensory evaluation revealed that the six kinds of Pixian board-bean paste were characterized by strong umami and saline taste. The free amino acids extraction process from Pixian board-bean paste by response surface methodology was obtained,which was convenient and feasible.The above research showed that there were some differences in the free amino acids components and content of six kinds of Pixian board-bean paste,and glutamate made the greatest contribution to umami taste.