Studies On Formation Control Of Methanol Of Apple Distilled Liquor Obtained By Solid-State Fermentation

The main problem of fruit distilled liquor production is excess methanol content,which restricts the development of fruit distilled liquor. In this study, Ralls apple origined from Yantai, Shandong province were used as raw meterial. Apple distilled liquor was obtained by solid-state fermentation.The controlling parameters of methanol content and alcohol productive rate were studied, including fermantation time, fermentation temperature, different treatment mode of raw meterial and so on. The experiment results show that pectinase B was added to raw meterial and the mixture was maintained for4h at30℃, then microwave treatment(700W,200g) for5min. After inoculation,batch fermentation was carried out at20℃for6d. Afterwards, the fermented material was distilled for a liquor with42%(v/v) alcohol content and the alcohol productive rate reaches97.2%. The concentration of methnol is29.66mg/100mL without rectification, which is far below the regulation of GB2757. It is bring about the desired result that not only the ethanol productivity was improved but also the methnol content was reduced.The activity of PG, PL and PE in6pectinases (A, B, C, EX, EX-V, HC) were determined. It was found that the higher the PG and PL activity,the higher the ethanol productivity and the higher the PE activity, the higher the methanol content. In the pectinase B, activity of PG and PL are highest and the activity of PE is lowest. It reaches5187.26U/g,152.25U/g and296.47U/g,perspectively. This kind of pectinase such as pectinase B is suitable for the production of distilled liquor obtained by solid-state fermentation of apple, which can improve the ethanol productivity and reduce the methnol concentration.The main component of apple was determined before and after fermentation. As the result, the mass of solid residue was reduced by6.22%, the crude protein content was increased by8.93%, ash content was increased by1.57%and the corase fiber centent was reduced by4.52%. The nutrient value of apple was improved when apple distilled liquor was obtained by solid-state fermentation. The fermentated apple can be used as feedstuff.It solve the problem of apple pomace treatment after squeezing.The process of apple distilled liquor obtained by solid-state fermentation is also suitable for production of mulberry, pineapple, litchi, peach and pear distilled liquor. It also can improve the ethanol productivity and reduce the methanol content at the same time.