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Stevioside Stevia taste compounds, the most important component of stevia glycosides (Stevioside, STV), Knight packages Di glycosides the A (rebaudiosides, A, referred to as RA) and the Knight package Di glycosides C (rebaudiosides C, referred to as RC). RC sweetness of sucrose 40-60 times as the STV 270-300 times as sweet as sucrose, but the taste is slightly bitter, RA 350-450 times as sweet as sucrose, taste the best quality and taste of effect closer to sucrose, stevioside highest quality ingredients, thereby increasing the proportion of RA content is of great significance for improving the quality of stevia. This test Stevia cultivars, topping processing, trace elements, lighting control, and harvesting and drying the main component of the stevia were studied. The results are as follows: (1) The results show that the different varieties of stevia, Morita quality is better than Morita 2 and Rudder, the main component of RA content of 9.83%, respectively, higher than 14.44% of Morita and Rudder and above the leaves of the best quality, RA content of 11.53% and 12.47%. (2) topping twice in the cultivation process is conducive to improve the quality of Stevia, Stevia leaves topping twice RC content, RA content of total glucosinolate content, free amino acids and crude protein content were significantly higher than other treatments, respectively, 1.12%, 10.01%, 12.24%, 4.98% and 19.58%. (3) the Stevia growth process, the RA and the total glycosides are gradually increased the RA of total glycosides ratio increased from 75.46% to 85.21%, the STV and RC ratio decreased from 17.64% to 8.33% and 6.89%, respectively, decrease to 6.47%. (4) spraying processing results of trace elements manganese fertilizer early branches sprayed with 3 mg / g of potassium permanganate treatment of RA content of total glucosinolate content and free amino acids were significantly higher than CK, 10.11%, 12.35% and 5.65%, no significant differences in other quality indicators and CK, higher and more heavy and mellow sweetness of Stevia compared to other treatments. Boron processing, optimized to 0.5 mg / g of boric acid treatment of Mycobacterium early RA content of total glucosinolate content and free amino acids were significantly higher than CK, respectively, 10.10%, 12.51% and 5.49%, STV content and CK was no significant difference in the crude fiber content significantly lower than CK, 16.72%, 0.77% lower than the CK, compared to other treatments sweetness of Stevia higher direct consumption is strong. Molybdenum fertilizer treatment, early branching spraying the effect of 3 mg / g ammonium molybdate treated with the best Stevia RA content of the treatment, the total glucosinolate content, free amino acids and crude protein content were significantly higher than CK, respectively 10.43%, 12.32%, 6.14% and 20.93%. And STV content of only 85% of CK, while the crude fiber content is 1.90% higher than CK. In zinc fertilizer processing, branching peak 3 mg / g of zinc chloride treatment effect best, the RA content and free amino acids were significantly higher than CK, 10.13% and 4.77%, respectively, STV content CK low of 11.65%, crude fiber content also significantly higher than CK, reached 17.19%. (5) Stevia light control results show that different shade processing time, a layer of shade net cover one week of treatment effect best, the crude protein content were significantly higher than CK, 20.06%. STV content is less than CK, 0.84%. Free amino acids, crude fiber content and the content of RA and CK was no significant difference in the sweetness of Stevia obtained more palatable. Different light was to cover the 2 layer shade net effect relative to other, the obtained RA content of total glucosinolate content, free amino acids and crude protein containing significantly higher than other treatments are 9.47%, 11.55%, 5.31% and 20.16%, respectively. Compared with CK, the stevioside content difference is not significant, the total free amino acid content of crude protein and crude fiber content was significantly higher than CK. (6) Stevia harvesting stevia lower leaves begin to age drop before picking better, get stevia leaves better quality, the RA content and total glucosinolate content reaches its maximum value, 10.54% and 12.37%, respectively. The study found that the drying temperature on stevioside content to 80 ° C treatment effect is better, retains more of RA and total glycosides, respectively, compared with 7.77% and 6.50% of the CK high, free amino acids and crude protein content is maintained at a certain the high level.
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