Study On The Technology Of Apricot Dregs Vinegar Fermentation With Immobilized Cells

In this study, the apricot dregs were used as a material. The production technology of the apricot dregsvinegar by immobilized yeast and immobilized acetic bacteria was studied. The preparation technology ofboth the immobilized yeast and the immobilized acetic bacteria were studied and the experiments of theirfermentation properties were conducted.The sodium alginate, polyvinyl alcohol and silica as the basiccarrier, the calcium carbonate, carrageenan, diatomite and gelatin as the adding materials were selected bythese measurement indexes, which were the permeability, infiltration capacity, mechanical strength,damage number, service life, alcohol degree and residual sugar. The continuous alcohol fermentation andbatch acetic fermentation of apricot dregs juice was researched. The aroma components and the aminoacids of apricot dregs original vinegar were decetected, and the hygienic indexes were tested.The resultsshowed that the optimal composition of immobilized yeast were calcium carbonate0.6%(g/100mL),sodium alginate4%(g/100mL), polyvinyl alcohol3.2%(g/100mL), Silica1.6%(g/100mL). In this condition,the immobilized yeast had high mechanical strength, good fermentation stability, shortened brewing-time,and high alcohol degree. The alcohol degree still maintained up to8.0%(v/v) after nine times batchfermentation for about40d. The optimal parameters of the continuous fermentation were as follows, wineyeast: ester yeast: lactic acid bacteria2:2:1(v/v), the dilution rate0.02h-1, the inoculums16%(g/100mL),the soluble solids17%, the temperature30℃, pH3.8, the alcohol content could reach6.3%(v/v). Theoptimal conditions of the acetic acid fermentation were as follows, the initial alcohol degree was6%(v/v),the inoculum was12%(g/100mL), the liquid volume was20%(v/v), the rotational speed was80r/min, pHwas4, fermentation for21d at30℃, the yield of acetic acid up to6.9g/100mL. The aroma components ofapricot dregs original vinegar was analyzed by gas chromatography-mass spectrometry. The aromacomponents was28species,included7kinds of esters,6kinds of alcohols,5kinds of acids, consisting of43.45%,14.8%，20.04%of the total volatile components respectively (the relative content). The ethyl acetate was the highest amount of aroma components, the highest amount of alcohol components was2-butyl octanol; the highest amount of acids components was acetic acids, and the relative content was23.81%,2.92%,10.05%respectively. It is identified a total of16kinds of amino acids in apricot dregoriginal vinegar, the total content of amino acid was1.0g/100mL. The content of aspartic acid is thehighest.The contents of arsenic, lead, aflatoxin B1, colony count, escherichia coli and pathogens in apricotdregs original vinegar were lower than criterion of GB18187-2000fermented vinegar and ZB X66004-86quality standard of vinegar by liquid process. The total acid6.9g/100mL>3.5g/100mL, the soluble solids5.0g/100mL>0.5g/100mL were higher than criterion of GB18187-2000fermented vinegar and ZB X66004-86quality standard of vinegar by liquid process.