Effect of Ulva flexuosa Wulfen Seaweed and Shirazi Thyme (Zataria multiflora) Extracts on Qualitative Characteristics of Washington Navel Orange under Sorage Period

In recent years, in order to improve qualitative characteristics of horticultural products, the researchers have considered the use of organic substances. This experiment was conducted to evaluate the effects of different concentrations of Ulva flexuosa Wulfen seaweed (endemic of Persian Gulf) and Shirazi thyme extracts on postharvest characteristics of Washington Navel orange under cold storage for 60 days (the qualitative characteristics were evaluated with 15 days interval). The results indicated that fruit weight loss, fruit decay, TSS (total soluble solids) content increased and juice %, titratable acid and ascorbic acid contents decreased at the end of storage period. Postharvest quality of Washington Navel fruits significantly improved when fruits were immersed in seaweed and Shirazi thyme extracts. On the other hand, seaweed extract was more effective in improving these characteristics of orange compared to Shirazi thyme. At the end of storage time, the most effective treatment was 0.94 g/l of seaweed extract, so that the maximum reduction in percentage of fruit decay was observed in this concentration. Also the highest (35.49) fruit juice percentage and the least (3.26%) weight loss were obtained in the concentration of 3.75 g/l of seaweed extract. Therefore, the results of this study showed that seaweed extract could be used as an active bioactive compound to improve qualitative postharvest characteristics of orange fruits.