Evaluation of the influence of pretreatment methods on the quality characteristics of okra hot-air drying based on the coefficient of variation method

Objective: Improve the quality of dried okra products. Methods: The rehydration ratio, shrinkage rate, vitamin C content, drying time and sensory score were used to analyze the effects of different pretreatment methods on the quality of dried okra products, and the coefficient of variation method was used for comprehensive weighted evaluation. Results: The results showed that blanching and ultrasonic pretreatment can significantly increase the rehydration ratio of the dried sample （P＜0.05）. The shrinkage rate was most affected by blanching. The vitamin C content of the pretreatment group was lower than that of the control group, and the ultrasound treatment group had the least loss. The blanching and ultrasonic pretreatment can shorten the drying time, and sensory scores of samples pretreated by ultrasound and color protection were significantly higher than those pretreated by blanching （P＜0.05）. The comprehensive evaluation by the coefficient of variation method showed that the quality of the okra pretreated by ultrasonic was the best, followed by the color protection treatment, and the blanching treatment had the lowest comprehensive score. When the ultrasonic pretreatment temperature was 20 ℃, the comprehensive score of the dried sample obtained was the highest, which was 0.907. Conclusion: The research showed that the ultrasonic pretreatment was a better pretreatment method with hot air drying of okra.