Changes in Enzyme Activities During Postharvest Deterioration of GreenAsparagus Spears

Abstract

Fresh asparagus (Asparagus officinalis L.) deteriorates rapidly after harvest. Early enzymatic changes that fol- low harvesting of asparagus are important factors contributing to postharvest deterioration. We held asparagus spears at 25°C for up to 5 days after harvest and examined changes in the activities of Acid invertase (AI), Sucrose Synthase (SS), Glutamine Synthetase (GS) and Phenylalanine ammonia Lyase (PAL) in both top and bottom portions of the spears. Solu- ble AI activity increased during the first day of storage and after that it decreased gradually up to five days in both top and bottom portions. Sucrose synthase activity was higher in the bottom portion than in the top; its activity declined daily for five days. Sucrose content was negatively correlated with invertase and sucrose synthase in both portions.GS enzyme ac- tivity in both top and bottom portion declined throughout the experimental period which may be related to increased am- monia accumulation. The increase in PAL activity continued until day 3 and declined thereafter.