Effect of some Technological Treatments on Physical Properties and Bioactive Components of Ripe Soft Persimmon Fruits

Abstract

Fruits of persimmon are considered as one of the health promoting foods which has been established as one of the major fruits. Persimmon is one of the fruits processed mainly by drying. Persimmon (Diospyros kaki coststa.) fruit is rich in health promoting substances. It contains health promoting bioactive compounds like, ascorbic acid, total phenolic and carotenoids, which have antioxidant properties. The objective of this investigation was to evaluate the quality of blanched and dried peel and pulp of persimmon fruits. This quality was estimated by determining of physical properties, chemical composition, some bioactive components and antioxidant activity of peel and pulp. To achieve this aims persimmon fruits were sorted and graded then washed and blanched to inhibit the enzymes during drying. Physical properties, Chemical properties and bioactive component were determined to evaluate the effect of blanching on dried persimmon peel and pulp. The obtained results showed that the L*(brightness) of unblanched and blanched dried pulp were 59.17 and 61.55, respectively. The values of a* (redeness) and b* (yellowish) of unblanched dried pulp were 1.37 and 18.85, respectively. The blanched treatment increased a* and b* values of blanched dried pulp. Therefore, the blanched treatment had a positive effect on dried persimmon. Bulk density was increased by blanching from 0.52 to 0.59 g/100ml, water holding capacity(WHO) increased from 80.5 to 85.9 g/100ml, oil holding capacity increased from 90.6 to 96.5 g/100ml and emulsifying capacity increased from 25.18 to 35.01 by blanching dried pulp. In the same time the blanching of the dried persimmon slightly increased moisture, protein, lipid, ash, carbohydrate and fiber for both pulp and peel persimmon. The decreasing rate of ascorbic acid in unblanched dried pulp was higher than blanched dried pulp (ascorbic acid was 180.3 mg/100g decreased to 150.8 mg/100g in unblanched dried pulp where it was 200.2 mg /100g in fresh pulp). Blanching had increased total phenol, β carotene and in the same time antioxidant activity percentage were increased in blanched dried pulp (75% , while it was 70% in unblanched dried pulp). The same trend for bioactive component was obtain for dried peel in ascorbic acid, total phenol, β carotene and antioxidant activity.