EFFECT OF IRRADIATION AND HEAT TREATMENTS ON THE QUALITY CHARACTERISTICS OF SIWI DATE FRUIT (PHOENIS DACTYLIFERA L.)

Abstract

The present work was carried out to improve the quality and the shelf-life of Siwi date fruit during storage time using irradiation and heat treatments, and investigate the effect of these treatments on the physical and chemical properties of the Siwi date fruit. Results showed that control dates samples (without treatments) contained 18.74% moisture, 1.72% crude protein, 1.21% fat, 2.62% crude fiber and 2.05% ash while in the irradiated date samples, the average percent contents were 17.65 moisture, 1.65 crued protein, 1.19 fats, 2.58 fibers and 1.97% ash. On the other hand, the results showed that the date fruit treated with heat had 19.48% moisture, 1.61% protein, 1.140% fat, 2.55% fiber and 1.99% ash. The results indicated that the moisture content of the control date samples decreased from 18.74 to 11.35% over a 9-month of storage while it decreased from 19.48 to 12.68% and from 17.65 to 11.82 over 9-months of storage for the heat treatment and irradiated samples, respectively. The results also showed that, during the storage period (9-months), the protein contents decreased from 1.72 to 0.80% for control; from 1.61 to 0.782% for heat treated samples and from 1. 65 to 0.80% for irradiated samples. In our study, all essential and non-essential amino acids increased sharply after the heat and irradiation treatments, compared with the control samples. The most affected amino acid appeared to be Aspartic acid, Glutamic acid, Serine and Tyrosine. The results demonstrated that the heat treatment samples had lower Valine content than the control and the irradiated sample. These results suggest that irradiation of Siwi date fruit at doses up to 1kGy could be used as alternative method for improving fruit quality, as well as prolonging the marketable period of date fruit.