Research On Suitability Evaluation And Crispness In Pickled Cowpea

Pickled cowpea was liked deeply by the large crowd because of unique flavor and promoting digestion, increasing appetite, and other effectiveness. With China's rapid and healthy economic development and people's living standard continued to improve, the demand for food has increased, and the study of how to improve the quality of pickles is of great significance. Nine Cowpea varieties, cultivated broadly in Hubei, were pickled, and we carried out an comprehensive evaluation on them by yields, plant diseases and insect pests as well as several aspects after pickling such as nutritive ingredients, color, brittleness, deleterious substances and so on. Selecting two varieties as raw material, the influential factors upon crispness of pickled cowpea, the mechanism and changing law of crispness during pickling were studied, the main study results were summarized as follows:1. There was a great difference on the quality to different varieties after pickling. According to the Grey Correlative Degree Analysis principle, the results showed that correlative value of 201 techang, gaochan 4 and shanjiang 6 are nearer to reference variety and comprehensive performances are good, so they are the most proper varieties for pickling.2. Based on single factor experiment which crispness was evaluation indexes including maturity, salt concentration, environmental temperature, blanching time, blanching temperature, CaCl₂ concentration and pickled time, the optimum process parameters were determined with three-factor quadric orthogonal regression composite experimental design.The mathematical models were established as followings:Y=61.41 +0.09X₁+0.17X₂-0.45X₃+0.25X₁X₂,-0.22X₁X₃+0.06X₂X₃-0.45X₁²-0.42X₂²- 0.74X₃²The crispness of pickled cowpea was noticeably affected by pickled time, salt concentration and CaCl₂ concentration in significant order. The model of crispness showed no significant lack of suitability at 5%, but it was statistically significant at 1%. The model was appropriate to express response variables. The scheme for getting crispness more than 61.49g was that CaCl₂ concentration 0.10%-0.11%, salt concentration 4.06%-4.20%. pickled time 7-8d.3. Crispness declined first and then increased and afterwards declined again during pickling. There was relationship between crispness of pickled cowpea and water content, cellulose content, water soluble pectin, petin content, pectinase and cellulase activity. Results revealed great divergence in comparison with three data statistics method: the grey correlation analysis results showed that the main fators influencing the crispness of pickled cowpea were pectin content, water content, cellulose content and pectinase activity in significant order; correlation analysis of parameters indicated that the crispness of pickled cowpea had significant negative correlation with water soluble pectin content, and positive correlation with water content and cellulose content; the stepwise regression analysis results showed that the main factors influenceing the crispness of pickled cowpea were water content, petin content, water soluble pectin content and cellulase activity. Overall, these factors affected the crispness of pickled cowpea directly or indirectly.