Studies On The Changes Of Main Components In The Period Of Fermented Cowpea

Fermented cowpea is one of Chinese traditional product cultivated locally, which has been recognised as one of the most famous pickling vegetables in Hunan Province, with its unique character, as aroma, taste and flavor, but local characteristics thick traditional salted. Fermented cowpea process has not yet been optimized, fermentation mechanism is lack of research either. Discusses the process improvement and the role of the enzyme and changes of chemical constituents is significant to fermented cowpea to update ceaselessly, process maturely and increase its quality.As raw materials, combining traditional method, research improved fermented cowpea processing technology, determined key parameters; preliminary proved enzyme composition and changes in different periods, and determined the main enzymes and fermentation process and the relationship; preliminary sure the changes of main chemical constituents and food safety evaluation of fermentation. The main research results are as follows:(1)Fermented cowpea had a better food technology conditions for, salt content10%, moisture content60%, fermentation temperature27℃. In the most optimal process conditions, through the test, measured protein content, free amino acid, volatile acid, volatile ester content of fermented cowpea were14.33%,0.8012%,1.7926%and0.1602%respectively.(2)In the process, pH was always neutral with slightly acidic partial, acid protease and alkali protease of enzyme activity were relatively small, neutral protease was always dominant, and finally reached peak43.22IU dry base. Under the action of protease, protein was resolved into small molecular peptide, its content eventually dropped to13.78%, the content of free amino acid increased, and eventually rose to0.7801%.(3)In the process, saccharifying enzyme activity reached a maximum on the5day,9.77IU dry base, then saccharifying enzyme activity decreased gradually as pH decreased. Total sugar content continued to decline, the drop range was greatly for the first15days and eventually total sugar content down to16.02%; the reducing sugar content had been kept relatively low for25d because of the decreasing of saccharifying enzyme activity, and consumption by microbial as part of carbon source at the same time, and eventually rose to1.48%.(4)In the process, total acid increased at beginning, was faster between10d～20d, and slower between25d-35d, eventually total acid content reached to the maximum,3.7104%; Volatile acid, volatile ester and trace ethanol showed a marked increase from10d, and tended to be lightly between25d-35d, eventually reached to the maximum,2.1855%,0.2268%and0.2237%respectively; the content of nitrate decreased sharply with the reduction time and closed to zero after25d, eventually fell to0.07mg/kg, showed fermented cowpea can install complete edible after25d.