Effect of modified atmosphere packaging on glutathione and ascorbic acid content of asparagus spears

Asparagus (Asparagus Officinalis L.) spears were packaged in ordinary and m icroperforated oriented polypropylene (OPP) films and were bored at 15C and 75% RH for up to 10 days. CO2 concentrations ranged from 15.5 to 23% at 10 days of storage. Weight loss was less than 1.2% in microperforated film pa ckages compared with 15% in air storage under similar conditions. Ascorbic acid content was found to be adversely affected at all the O-2 levels (1-6% ) prevailing in microperforated film packages, bur it was retained to the e xtent of 45-55 % of its original concentration in ordinary OPPfilm packaged asparagus. The O-2 concentrations in microperforated film packages were al so associated with higher glutathione concentrations in packed asparagus sp ears. Results of the study indicated that to preserve ascorbic acid and glu tathione simultaneously in stored asparagus through MAP under high CO2 and low O-2 conditions, O-2 concentration levels must be selected between I and 6% in such a way so as to get acceptable retention levels of ascorbic acid and glutathione.