Aspergillus Tempeh. M Melanin Fermentation Conditions And Characteristics Of The Volatile Components

The major reason that causes color change of touchi is due to the melanin substances produced by maillard reaction in the post-fermentation process.The structural and functional features of melanin substances produced in the reaction are still not well known, and further research is necessary to make a clearer definition.This paper mainly focused on the optimization of processing conditions of melanin substances with with pure Aspergillus oryzae, in the post-fermentation process; extraction and purification of melanin substances; determination of physical and chemical properties and stability of melanin substances; and comparison of volatile ingredient between Huayue touchi and the touchi fermented with pure Aspergillus oryzae, the major results are as follows:1.The orthogonal test on the optimization of melanin producing condition were done:Under the condition of 8% salt(w/w),2% alcohol(v/w),50℃and 15d fermentation, the level of melanin was higher than usual.2.The orthogonal test on the extracting condition was done.It showed that extraction level was 3,temperature 60℃,extraction time 180 mins and the ratio of material to liquid 1:15.3.The physical and chemical properties and stability of melanin substances were preliminary studied, which showed that melanin substances was more stable below 80℃,most of the ions showed little effect on the stability of melanin substances except for Al3+,Fe3+ etc.In addition, melanin substances showed excellent reducing resistance, but poor antioxidant.4.Via a comparison of volatile components between Huayue touchi and touchi fermented with pure Aspergillus oryzae, we found that carbonyl componds and esters of Huayue touchi are relatively lower than touchi fermented with pure Aspergillus oryzae, however the content of acids of Huayue touchi are higher than the latter.