Effect of different harvest maturity on storage quality of loquat 'Xinbai No. 8' at room temperature

Abstract: 【Objective】Loquat'Xinbai No. 8'is a new bred, high quality, late maturity and white-flesh cultivar with large-size fruit in recent years. Differences and changes of storage and quality of different harvest maturity of'Xinbai No. 8'at room temperature were discussed in order to provide references for improving scientific harvest and rational storage technology of this cultivar.【Methods】The fresh fruit of loquat cv.'Xinbai No. 8'at 70%, 80%, 90% and 100% maturity stored at room temperature for0, 1, 4, 7, 10, 13 days were compared. Water loss rate of fruit, rate of rotten fruits, and rate of wrinkled fruits were counted. Dynamic changes of chromatism index of fruit peel (L*, a*, b*, c*and H0), pulp firmness, TSS, sugar composition(Sucrose, fructose, glucose and sorbitol), acid composition(Malic acid,quinic acid, lactic acid and fumaric acid) and other quality indicators of fresh fruits of'Xinbai No. 8'were measured.【Results】With the prolongation of storage time, the Hovalue of fruit at each maturity showed an orderly slow downward trend, the a*value showed an orderly upward trend, the L* value decreased slightly during storage, and the changes of b*value and c*value all showed firstly upward, then downward and upward trend. a*value and H0 value of fruits at 70%, 80%, and 90% maturity stored for13 d, 7 d and 1 d made approximation to that at 100% maturity stored for 0 d. Water loss rate of fruit showed parabola rising, and the water loss rate at 70% maturity was higher than that at other maturities.When fruits were stored for 13 d, the water loss rate reached 4.15%. After 4 d-storage, the wrinkled fruit rate at 100% maturity increased rapidly, up to 34.71% when stored for 13 days, and the wrinkled fruit rate at 80% and 90% maturity increased slowly, and the wrinkled fruit rate at 70% maturity could not be found. Rotten fruit rate increased with the prolongation of storage time and fruits at 100% maturity had the highest rotten fruit rate, and rotten fruit rate was as high as 44.29% when storage time reached 13 days, followed by fruits at 70% maturity which had rotten fruit rate of 27.67% while fruits at80% and 90% maturity which had the lower rotten fruit rate of 20.96% and 19.00%, respectively. The pulp firmness at each maturity has a slowly increasing trend and it increased by 0.19-0.52 kg · cm^-2 after13 days storage. The higher the maturity of the fruit was, the greater the increasing scope was. The soluble solids and total sugar content increased slightly from 0 to 4 days of storage, and since then they had all declined slowly. Finally, the soluble solids content decreased by 1.20%-1.49% while total sugar decreased by 14.11-18.53 mg · g-1. The fructose content showed an upward trend with an increase of 3.19-9.31 mg·g-1, and the increase at 70% maturity was the largest. The glucose content increased before storage of 7 days, and the glucose content at 90% and 100% maturity after 7 days decreased by 13.65% and18.49%, respectively. Sucrose content of fruits at each maturity had the largest variation, which increased by 12.03%-16.08% in storage of 1 day, and after 1-7 days showed a declining trend by 32.62-71.11%, with the exception of fruits at 100% maturity and of which fruits at 70% maturity decreased the most. The content of sorbitol content decreased after the first increase during storage, of which fruits at100% maturity increased the most by 64.28%. The total acid and malic acid content showed the similar decreased trend. The lower the fruit maturity decreased, the greater the decrease scope was. Total acid at70% and 80% maturity decreased by 47.04% and 35.45% while the malic acid decreased by 48.81%and 37.21%, respectively. The contents of quinic acid and fumaric acid fluctuated during storage, but there was no significant difference between before and after storage. The content of lactic acid decreased after increased for 4-10 days. The ratio of sugar to acid and the solid acid to acid showed an ascending-descending-ascending fluctuation. At storage of 10-13 days, the ratio of sugar to acid and the solid acid to acid at 80% maturity were similar to those at 100% maturity before storage. However,fruits at 70% maturity still failed to increase to this level.【Conclusion】After room temperature storage,fruit color at 70% maturity showed gradually full maturity, fruits show no wrinkled skin but rotten fruit rate was high. Moreover, the total acid content reached highest while the sugar content was lowest, so edible quality of fruit at 70% maturity was poor. At 100% maturity the sugar content reached highest while the total acid content was lowest, so fresh fruit had best taste. However, on the fourth day at room temperature storage, winkled and rotten fruit rate at 100% maturity rapidly increased, good commodity showed downward trend significantly and fruits had weak flavor and less juice. Moreover, fruit pulp became firm and a small amount of stone cells appeared. Then edible quality of fruits decreased. After room temperature storage, fruits at 80% and 90% maturity had slowly decreased sugar and acid content,appropriate sweet and sour taste, good flavor and medium wrinkle and rotten fruit rate. It is concluded that fruits at 80% and 90% maturity are more suitable for storage at room temperature and had less than10 d for good storage effects. Fruits at 100% maturity should be sold or used for fresh fruit as soon as possible and stored at room temperature for less than 4 days.