关键词: 豇豆, 泡菜, 低盐贮藏, 中短波红外干燥

Abstract: Changes in the hardness and color value of fresh cowpea were investigated under different blanching conditions and at different concentrations of browning inhibitor. Then medium-short wave infrared drying technology was used for partial dehydration processing of the pretreated material to determine the effects of radiation temperature, power and distance on the drying characteristics of cowpea. Furthermore, the quality change of pickled cowpea during storage was investigated and two fermentation methods were compared for improving the color and hardness. Results showed that the softening and browning of cowpea could be delayed by blanching at 90 ℃ for 1 min and soaking in 20 g/L calcium lactate solution. The infrared drying conditions were as follows: 70 ℃, 900 W and radiation distance of 10 cm, 50 min. The critical moisture point of semi-dry cowpea was 70%. After 4 weeks of storage, the total number of colonies was 4.4 × 103 CFU/g and the most probable number (MPN) of coliforms was under 3 MPN/g, indicating good microbiological quality. The optimal rehydration condition of semi-dry cowpeas was 20 ℃ and 3 h. Pickle brine was more suitable to obtain improved cowpea pickle quality.

Key words: cowpea, pickles, low-salt preservation, medium-short wave infrared drying