| Okra(Abelmoschus esculentus)is an annual herb,like to grow in hot places,is a national promotion of cash crops,can be used in catering,medical,health care and other industries.However,in the process of storage,transportation and processing,okra is easily oxidized and deteriorated by external environmental factors,resulting in a decrease in freshness and loss of nutrients,thus losing its economic benefits.At present,due to the high planting quantity of okra,the storage process of okra is faced with many serious problems.In this paper,starting from the study of the nutrition composition,drying method and the development of new products of okra okra,the study of the nutritional composition of okra okra,the effect of drying on its quality and the preliminary utilization of okra dried products.The results are as follows:(1)The fresh seasonal okra was used as the test material.The moisture content of okra was 89.81%,the crude protein content of okra was 1.63%,and the crude fat content of okra was 0.86%.The content of soluble sugar and reducing sugar in okra was 6.83mg/g and 0.62 mg/g,the content of vitamin C was 34.78 mg/100 g,the total phenol was5.31 mg/g,and the flavonoid was 3.33 mg/g.the total amount of carotenoids in fresh okra was 46.8 ?g/g,wherein the lutein content was 25.99 ?g/g,and the zeaxanthin was 11.55?g/g,the ?-carotene was 9.16 ?g/g.It contains 18 kinds of amino acids required by the human body,and the total amount of amino acids is 98.04 mg/g(dry weight).The content of magnesium,phosphorus,potassium and calcium in the okra is high,and the inorganic elements are abundant.(2)Taking the commercially available fresh okra as experimental material,the effects of three drying processes,such as hot air drying,microwave drying and vacuum freeze drying,on the texture,nutrient composition,chlorophyll and antioxidant activity of okra were studied.The results showed that the quality of okra was changed to different degrees by three different drying methods.The effects of hot air drying and microwave drying on the texture,soluble protein,vitamin C,soluble sugar and antioxidant activity ofokra were studied maximum.Among them,freeze-drying has little effect on quality,and the quality is close to that of fresh okra.Three drying methods showed that there was a significant correlation between flavonoids and polyphenols in okra and reducing power and DPPH· assays.(3)The fermentation technology of okra yogurt was studied with freeze-dried okra powder and fresh cow milk as main materials.With ratio of water holding and sensory score as evaluation indexes,the process for production of okra yogurt was optimized by response surface methodology based on single-factor experiments.By analyzing the experimental data using Design-Expert V8.0,the optimum fermentation parameters were determined as follows: freeze-dried okra powder addition of 0.37%,inoculation quantity of 4.1%,fermentation time of 5.3 h and fermentation temperature of 41.8 ?.Under these conditions,the comprehensive index of yogurt was 0.9895 showing a relative standard deviation of 0.97% compared to the theoretical value of 0.9991.The okra yogurt obtained under the optimized fermentation conditions exhibited exquisite mouth feeling,unique flavor and elegant aroma,and the basic physical and chemical indexes conformed to national standard of yogurt. |
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