TEXTURAL AND COMPOSITIONAL CHANGES OF GREEN AND WHITE ASPARAGUS SPEARS DURING STORAGE

A textural and compositional comparison of green and white asparagus (Asparagus officinalis L. cv. 'Grande') during storage was carried out. Spears harvested from a commercial plantation on the 28th, 35th and 42nd day during the 60-day harvest season of 1999 were stored for 6 days at 1 or 10 oC. The changes in fibre content of the white spears were larger than those of the green ones, indicating that postharvest textural changes proceed more rapidly in the former and therefore the spears become tougher than those of green asparagus. The postharvest colour changes after storage at 1 oC include the appearance of an intense purple colour at the tip of the white spears, due to anthocyanin synthesis and the degradation of chlorophyll at the tip of green spears. The losses of ascorbic acid during storage were larger in the green spears, especially at the higher storage temperature. A decrease in the total soluble phenols was observed only in the green spears. The green spears were susceptible to negative geotropic growth curvature or bending, especially when the spears were placed horizontally at 10 oC. No geotropic response was observed in the white spears.