No abstract

The effect of fermentation on nitrate, nitrite and organic acid contents in pickled Chinese cabbage and brine was researched. The nitrate content in pickled Chinese cabbage decreased from 1,303.5 and 1,380.5 mg/kg to 245.7 and 354.9 mg/kg, respectively, during the natural and inoculated fermentation. The peak content of nitrite was formed in pickled vegetables and brine during the natural fermentation. The nitrite was at a low level in pickled Chinese cabbage and brine during the inoculated fermentation. During the 7‐day natural fermentation, lactic acid increased from 22.4 to 3,117.3 mg/kg, acetic acid increased from 32.9 to 254.6 mg/kg and citric acid increased from 8.3 to 255.8 mg/kg, and the responding results were 27.9 to 3,559.9 mg/kg, 40.5 to 572.1 mg/kg and 13.4 to 268.0 mg/kg, respectively, during the inoculated fermentation. When the pH of the brine was lower than 4.5, the peak content of nitrite gradually decreased. PRACTICAL APPLICATIONS Pickle is a traditional Chinese fermented vegetable product. It has been widely consumed in China for many centuries. In many families, the homemade pickle is popular. There are also hundreds of industrial pickle‐processing factories. It is necessary to focus on the quality of the pickle. The research presented in this paper showed that during the pickle processing, the peak content of nitrite that formed far exceeded the limit value of the nitrite content recommended by the World Health Organization. This research can be a guide for pickle processing both in families and in factories.

Douchi is a traditional Chinese soybean‐fermented food. For preparation of a functional douchi with high fibrinolytic activity, the effect of soybean variety on the fibrinolytic activity and sensory characteristics of douchi was investigated. Douchi was prepared by inoculating the cooked soybean made from 15 soybean varieties [Glycine max (L.) Merr.] with Bacillus subtilis DC33 and fermented at 30C for 30 h. The soybean variety affected the fibrinolytic activity, amino nitrogen and sensory characteristics of douchi significantly. The soybeans that had higher soluble sugar and smaller 100‐grain weight produced the better douchi with higher fibrinolytic activity. Yellow soybeans with round seeds were more appropriate to process douchi than black ones. Longxiaolidou 1 was screened out as the optimal variety for processing fibrinolytic douchi with regard to sensory properties. It is suggested that varietal differences should be considered when selecting soybeans for douchi production. PRACTICAL APPLICATIONS Douchi is a traditional soybean‐fermented food with a long history; however, there is very little research about douchi. Recently, douchi are still mostly processed by the traditional natural fermentation with a small scale of production. Therefore, the processing of douchi is not yet industrialized. Comparing douchi to material soybean, the physiological activities in douchi has a great improvement. In order to improve the thrombolytic activity in douchi, the douchi in this study is prepared by inoculating Bacillus subtilis DC33 with a high fibrinolytic enzyme yield to produce functional douchi. The effects of soybean varieties on the traits and sensory characteristics were studied. The optimal soybean variety for processing fibrinolytic douchi was screened out. The result has the guiding significance to process fibrinolytic douchi.

Changes in microflora during salting Chinese cabbage were studied, with special attention given to the effects of salt concentration, time and temperature of the process. Total mesophilic aerobic bacteria (TMAB), bacterial endospores (B. endospores), lactic acid bacteria (LAB), Enterobacteriaceae and fungi were used as control parameters. LAB accounted for 0.1-1% of total bacteria. Best process conditions for highest undesirable microbial inhibition were: salt 8% (w/v), temperature 15°C, and salting time 8 h. High levels (Ͼ10 5 cfu/g) of TMAB and Enterobacteriaceae were found in the whole salting time, and 90% of TMAB was identified as Gram negative. The levels of fungi, LAB and B. endospores after 12 h of the salting process were lower than 10 4 , 10 3 and 10 2 cfu/g, respectively.