Studies On Solid State Fermentation Technology Of Apricol Dreg Vinegar

In this paper the fermentation technology in the solid state of apricot dreg vinegar was studied. The acetic acid bacteria which is suitable strain in the fermentation of apricot dreg vinegar has isolated and identified. The experiments of both the protoplast preparation and the orientational mutagenesis with the protoplast from the isolated acetic acid are conducted. The parameters of technology which are:the preparation of rice mash, solid state alcohol fermentation solid-state acetic acid fermentation, clarification and sterilization of apricot dreg vinegar are studied. The volatile aroma components of apricot dreg original vinegar are determined. The results showed:that the strain AcO2was isolated from the natural fermental.The acetic acid yield of the strain AcO2can reach3.04g/100ml.The similarity of16S rDNA sequence is more than99%between the strain AcO2and Acetobacter pomorum strain LMG18848.The rate of protoplast preparation is81.68%and the rate protoplast regeneration is39.29%when the strain AcO2was treated by0.20mg/ml lysozyme for60min. The mutant F1was obtained after the protoplasts of the strain AcO2was treated by ultraviolet (UV) and nitrosoguanidine (NTG). The acid acetic yield of mutant F1, reached3.33g/100ml, and increased by11.10%compared with the strain AcO2, and genetic stability is good. The liquefaction conditions of rice mash were as follows:25%rice mash was hydrolysedby the a-amylase solution (12U/g) at65℃for’45min.Then dextrose equivalent (DE) value can reach16.064%the optimal conditions of saccharification for rice mash were180U/g of glucoamylase70℃for180min, the content of reducing sugar is56.496%. The mixture of the apricot dreg pulp and the rice mash were heated for sterilization at100℃for5min.The optimal parameters of the solid state alcoholic fermentation:17%of the initial soluble solids content,4.50%of the inoculation amount with Saccharomyces cerevisiae and2.30%of the inoculation amount with Ester production yeast, fermentation time is6days, the alcohol content is7.05%(v/v). The process parameters of solid state alcohol fermentation:6%initial alcohol content,14%inoculum amount with F1, fermentation time is25daysfermentation temperature is31℃, the content of acetic acid could reach8.16g/100ml.4%bentonite solution was used to clarify apricot dreg vinegar6ml/100ml for24hours, and the rate of light transmittance reached86.90%. Sterilization conditions were that the apricot dreg vinegar was treated at75℃for3min. The results of volatile aroma components of apricot dreg original vinegar were as follows:32species of esters, whose relative content is63.80%;21kinds of alcohols, consisting of3.47%of the total volatile components; aldehydes, consisting4.14%of the total volatile components;12kinds of acids, whose relative content is11.81%; vinyl material, whose relative content is only0.04%; other substances identified contains a total of17species, whose relative content is1.99%. It is identified a total of17kinds of amino acids in apricot dreg original vinegar. The content of aspartic acid is the highest.