| This study aims to obtain a kind of quinoa health vinegar with good flavor and strong function.The saccharification process of quinoa vinegar was optimized by using the functional characteristics and fermentation performance of mash as the evaluation index.The precipitation phenomenon and product flavor of quinoa vinegar were studied.Strains and combination proportions of microorganisms were optimized,and Daqu fermentation was strengthened to obtain high-quality quinoa vinegar via the process of alcoholization and acetification.Through taste optimization,we were able to obtain a quinoa health vinegar beverage with high clarity and acceptability;which provided us theoretical guidance for the recognition of the function and high value of Shanxi coarse grain vinegar.The main research methods and results are as follows:1.9 influencing factors of quinoa saccharification such as the amount of water and ?-amylase and the liquefaction and saccharification time were evaluated via Plackett Burman experiment design.Four factors with significant effects were screened out in order to improve the final quality of the quinoa fermentation products,obtain quinoa saccharification mash with good fermentation performance,and more functional components based on the single factor experiment.The best quinoa saccharification technology was determined according to the central combination experiment design principle: water content 500%,gelatinization temperature 80 ?,gelatinization time 40 min,liquefying enzyme content 800 U/g,liquefying temperature 80 ?,liquefying time 17 min,saccharifying enzyme content 4000 U/g,saccharification temperature 65 ?,saccharification time 50 min.Under the optimum conditions,the total flavone content of quinoa mash was 185 mg/100 m L,the reducing sugar content was 11.9 g/100 m L,and it had the unique fragrance of quinoa;2.The best conditions of quinoa wine and vinegar were determined via screening and application of superior yeast,lactic acid bacteria,and acetic acid bacteria,and the quality of quinoa Jiulao and Cupei improved.Based on the bacterial tolerance test,the dominant bacteria during the fermentation stage were identified as yeast Y18 and lactic acid bacteria L20.The best technology of quinoa fermentation was determined through the control test as follows: adding 0.5% of yeast Y18 culture liquid and 0.3% of lactic acid bacteria L20 culture liquid,the fermentation temperature was 35 ?,and there were 7 fermentation days.Under these conditions,the alcohol content of quinoa mash was 8.3%Vol,total flavone content 141.3mg/100 g,nonvolatile acid content 1.39 g/100 g,total ester content 3.53 g/100 g.Based on the tolerance test of acetic acid bacteria,the dominant bacteria were determined to be acetic acid bacteria A14 and A15,and the best technology of quinoa acetification was determined: add 6% mixed acetic acid bacteria(A14:A15=1:2),fermentation temperature 36 ?,10 fermentation days,under which the total acid of quinoa acetified grains was 4.79 g/100 g;19.7% higher than CK,the content of nonvolatile acid was 1.66g/100 g which is 36.1% higher than CK,the content of total flavone is 133.5 mg/100 g,which is 7.1%higher than CK,the content of total ester is 4.02 g/100 g;25.6% higher than CK.3.Under the premise of minimizing the precipitation and unstable suspension of quinoa health vinegar,the flavor and taste of the vinegar were optimized.Among the 6 alternative stabilizers,chitosan,xanthan gum,and CMC-Na were selected as stabilizers for quinoa health vinegar;the best combination of the three stabilizers was 0.10% chitosan,0.10% xanthan gum and 0.05% CMC-Na.Results of sweet acid ratio interaction test indicated that quinoa vinegar has the best flavor when the acidity of quinoa vinegar is 1.5%,xylitol content is 2%.The physical and chemical indexes of the final product are: acidity 1.47 g/100 m L,nonvolatile acid 0.47 g/100 m L,sugar content 2.31 g/100 m L,total flavone 43.5 mg/100 m L,total ester1.18 g/100 m L,amino acid nitrogen 0.51 g/100 ml. |
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