The Change Of Physiology And The Study Of Sugar And Cell Wall Mechanisms On Sweet Persimmon At Post-harvest

Five maturities of’Fuyu’sweet persimmon fruit (Diospyros kaki’Fuyu’) was used as the experimental material of this article. We could discussed the change of fruit special flavour quality index and effect of carbohydrate metabolic and cell wall metabolic of’Fuyu’sweet persimmon fruit, by measuring fruit quality、carbohydrate composition、related sugar metabolic enzymes、cell wall matter、cell wall degrading enzymes activity during storage at atmospheric temperature and low temperature(4±1℃) at regular intervals. The results indicated that:1、Five colour (from yellow-green to orange-red) was divided according to peel colour of’Fuyu’(priority to the equator). With turning red of fruit peel colour, the ripeness and soluble solid were rised and hardness was reduced gradually of these five maturities. It could judge grade of maturity of sweet persimmon accurately and intuitively with colour chart through peel colour.2、The materials of five maturities were researched the change of hardness、 respiratory rate、rotted ratio、rate of water loss、side in length and breadth、index of fruit shape and soluble solid. The dates showed that it was not suitable long-term storage at the atmospheric temperiture, because of the high water loss rate and rotted rate; Maturity I and II fruit suited storage in21d and Maturity III and IV was in15d at short-term room temperture. However, Maturity V fruit was suitable for eating at postharvest. While it could control the decline of fruit hardness, reducing the rate of water loss and rotted, delaying the up of soluble solid at low temperature. There was good quality of fruit in five maturities when storage35d at low temperature, because of nice hardness and crisp felling and moderate TSS. But most of fruits were soften and quality was poor after35days. So, it suited to storage35d at low temperature. Maturity II was the best ripeness of these five maturities, secondly Ⅲ、Ⅰ andⅣ. While maturity V should not be long-term storage for14d.3、According to maturity Ⅱ、Ⅲ、Ⅴ of’Fuyu’sweet persimmon fruit, the change of carbohydrate composition and sugar metabolic enzymes were studied in the postharvest and during of storage. The consequence manifest:fructose and glucose were uptrend, but rising of reducing sugar could be controled at low temperature. And sucrose was extremely low at the whole storage. Low temperature could inhibit the up of invertase activity, yet there was little effect to SS-clastic enzyme. Therefore, AI、NI and SS-c regulatory and control the accumulation of reducing sugar at the atmospheric temperiture.4、According to maturity Ⅱ、Ⅲ、Ⅴ of’Fuyu’sweet persimmon fruit, the variation of cell wall matter and cell wall degrading enzymes activity were studied in the postharvest and during the storage. The consequence indicate:when harvested the grade of maturity was lower, the protopectin was less, the more water soluble pectin was. With storage time extending, the activity of PG、Cx and β-Gal went up. It could accelerate protopectin declining and water soluble pectin rising constantly. Protopectin、cellulose and water soluble pectin could be control, the activity of PG and β-Gal could be put off at earlier stage of low temperature. Among whole storage, fruit hardness had significantly positive correlation with protopectin and cellulose, water soluble pectin was opposite.5、In conclusion, there was two apparent descending stage of fruit firmness at the storage. Descending of fruit firmness was concerned with cellulose in the first stage and pectin in the second stage. In my experiment, descending of fruit hardness was caused by reducing of cellulose content at earlier stage and reducing of pectin content at later. Maturity Ⅰ-Ⅳ fruits were appropriate for short-term storage at room. There was good quality before14-21d and poor quality after21d. There was good quality of fruit in maturity Ⅱ when storage35d at low temperature, because of nice hardness and crisp felling and moderate TSS. But most of fruits were soften and quality was poor after35days. So it suited to storage at most35d at low temperature. Secondly, maturity III and IV suited to storage less than28d. Because of low maturity, maturity I tasted lightly at low temperature. While maturity V should not be long-term storage for14d. At last, maturity Ⅰ-Ⅲ fruit of sweet persimmon was fit for putaway when storage between21-28d at low tempreture, and maturity Ⅳ fruit was28d. And the shelf time did not exceed one day.