Study On Brewing Technology Of Coix Seed Vinegar

Coix is a kind of grain with rich and balanced nutrition,which contains protein,various amino acids,vitamins,minerals and flavones.Its nutritional value and health value far exceed other grains,and it is known as "the king of gramineous plants in the world".Modern pharmacological studies have shown that coix has anti-tumor,immune enhancement,hypoglycemic and anti-inflammatory activities.But Coix is difficult to cure,the characteristics of cooking difficult limits its consumption,so the development of coix deep processing products has important practical significance.In this experiment,coix seed and sorghum were used as raw materials,based on the traditional brewing process of shanxi aged vinegar,the dominant active dry yeast was screened,and the process parameters of each stage of the brewing process of coix vinegar were optimized by single factor test,orthogonal test and response surface design,so as to brew a functional vinegar with the nutritional and health value of coix vinegar.The experimental results are as follows:(1)The optimum conditions for the gelatinization of coix were that the number of crush mesh of coix is40 mesh,the material-water ratio is 1:5,the gelatinization temperature is 75?,and the gelatinization time is 100 min.Under the optimized conditions,the gelatinization degree of coix mash was 34.4%,the color of gelatinized mash was uniform,the odor was coordinated,the consistency was good,and the sensory evaluation was excellent;(2)Three main factors that significantly affect the content of reducing sugar and total flavonoids in barley mash: liquefaction temperature,liquefaction time and saccharifying enzyme addition.Through box-behnken experimental design and response surface analysis,the optimal process conditions for the saccharification of coix were determined as follows: sorghum addition 0.8 times,feed water ratio 1:3,?-amylase addition 0.3%,liquefaction temperature 81.5?,liquefaction time 47 min,saccharification enzyme addition 1.9%,saccharification temperature 60?,and saccharification time 40 min.Under these conditions,the content of reducing sugar and total flavonoids in the coxi's saccharified mash can reach13.2g/100 mL and 136.55mg/100 g respectively.The content of reducing sugars and total flavones increased by 22.2% and 34.8%,respectively,compared with that of coix seed mash without process optimization;(3)The optimal fermentation conditions of each of the four active dry yeasts were respectively determined as danbaoli yeast.:the fermentation temperature was 32 ?,the yeast addition amount was1.2 ‰,and the initial pH was 5.5.Fermenting yeast: the fermentation temperature was 30?,the yeast addition was 0.7‰,and the initial pH was 5.0.La-ba yeast: the fermentation temperature was 27?,the yeast addition was 0.5‰,and the initial pH was 5.0.Angel yeast: the fermentation temperature was 30?,the yeast dosage was 0.8‰,and the initial pH was 5.5.The best active dry yeast was selected as Fermenting yeast.(4)The three factors that had significant influence on the degree of alcohol,which were the initial sugar degree,yeast inoculation amount and fermentation temperature.The optimal process condition is: the initial pH is 5.0,the initial sugar 14%,yeast inoculation quantity of 0.6 ‰,29 ? fermentation temperature,fermented eight days.Under these conditions,the alcohol content of the coix wine mash can reach11.5%vol.(5)Three factors with significant influence on acidity were selected by orthogonal test,which were initial wine degree,yeast inoculation amount and fermentation temperature.The optimal technological conditions for the vinegar fermentation of ciox vinegar were determined as follows: the initial pH was 4.5,the initial liquor degree was 18%vol,the inoculation amount of acetic acid bacteria was 4‰,the fermentation temperature was 36.5?,and the fermentation days were 10 days.Under this condition,the acetic acid degree of coix vinegar was up to 6.35g/100 mL.(6)The physical and chemical indexes of coix vinegar were determined and showed that the acidity of coix vinegar was 6.35g/100 mL,the total ester was 1.41g/100 mL,the amino acid nitrogen content was0.43g/100 mL,the non-volatile acid content was 2.45g/100 mL,and the reducing sugar content was1.38g/100 mL;During the fermentation process,the content of total flavones showed an upward trend in the vinization stage,decreased slowly in the first four days of the vinization stage,and then increased slowly.The content of total flavones reached 198.35mg/100 g after the completion of the vinization and fermentation,24.2% higher than pure coix vinegar.;coix vinegar contains 18 kinds of amino acids,including8 kinds of essential amino acids;The finished product of coix vinegar obtained from the optimization of brewing process is pure in color,rich in vinegar flavor,soft and mellow in taste,with typical aroma of coix vinegar,and the sensory score can reach 9.5 points.