Enzyme Activity And Chemical Property In Sufu Production

The changes of chemical compositions, enzyme activities, and properties of rheology during sufu production were studied in the paper.The research on enzyme activities showed, generally, that the higher relative humidity, the higher yield of enzyme at the given temperature. The result showed that the optimum conditions for A. elegans and R. oligosporus were 30? and 35?, respectively. So R. oligosporus can be used in the sum manufacture in hot summer.The study on chemical compositions showed that the protein in sufu with low-salt content (5% and 8%) decreased rapidly during the ageing by contrast with that of sufu with high salt-content (11%), and so did the total acid and free amino nitrogen. But the crude fat decreased much slowly by comparing with that of protein, and the increasing rate of free fatty acid was not significant during the ageing. The pH showed that sufu with 5% salt spoiled during the ageing, but sufu with 8% or 11% salt content remained high quality.The study on properties of rheology of sufu showed that the hardness of sufu decreased rapidly during sufu ageing, and hardness of sufu after 80 days fermentation was only 10 to 15% of that of tofu. The spring of sufu decreased 40-45% by comparing with that of tofu, but the adhesiveness increased during sufu fermentation, and the adhesiveness of sufu after 80 days fermentation was 12-15 times of that of tofu.