Study on the Physicochemical Index Variation of the Sweet Sorghum Fermented Grains Mixed with Stalks

【 Objective 】 The purpose of this study is to make clear the temperature, humidity change characteristics and the physical and chemical index of the sweet sorghum fermented grains and understand the correlation between the factors.【 Method 】Using the whole plant (including spike) of sweet sorghum as raw materials for solid state fermentation, timing sampling and analysis the fermented grains temperature,moisture content, alcohol, total sugar, reducing sugar, protein, acidity. The correlation between alcohol and physical and chemical indexes was analyzed by SPSS software.【 Result 】The temperature of all parts of pits were different, the fermented grains temperature was: upper > middle > lower,and the upper fermented grains heating and cooling process went on more smoothly than the middle and lower parts. The fermented grains humidity center area changed more slowly than the surrounding areas. Change characteristics of region and its surrounding regions with a layer of fermentation of fermented grains temperature center was different. The same layer center area and the surrounding area fermented grains temperatures were different, and changes in central area of fermented grains temperature was relatively slow. The humidity of fermentation increased by 10%rh,the fermented grains humidity was: lower > middle > upper,centre of fermented grains humidity changed more slowly than the surrounding area. Fermented grains physical and chemical index change rule was: ① The alcohol content increased first and then decreased, and at the time of 156 h it reached the highest value 12.5%; ② The content of total sugar and reducing sugar decreased rapidly and stabilized gradually after sixth days; ③ After fermentation, protein content increased from 5.1% to 8.6%, which was increased by 68.5%.【 Conclusion 】Based on the variation process of fermentation of sweet sorghum grain and stalk physicochemical index, the appropriate pit distillation time is selected, which can effectively improve the yield of ethanol. The production of ethanol from sweet sorghum grain and stalk in solid state fermentation not only realizes the energy conversion of sweet sorghum, but also improves the nutritional value of sweet sorghum fermentation residue as feed.