Effects of misting and modified atmosphere packaging on nutrient and market quality of broccoli

Abstract

Vegetables are significant sources of nutrients in the human diet. Therefore, it is important to evaluate effects of new postharvest storage technologies on quality attributes of vegetables. Two recent techniques used by retail produce industry to extend shelf-life of vegetables are automatic misting and modified atmosphere packaging (MAP).

Moisture, vitamin C, color and texture changes were assessed in misted and nonmisted broccoli samples at 0, 24, 48 and 72 h during cabinet display (16$\sp\circ$C). Reduced ascorbic acid (RAA) determinations, ascorbate oxidase (AO) and peroxidase activities, total chlorophyll extractions, Hunterlab color and Instron texture measurements were done. Misting significantly enhanced moisture, RAA, chlorophyll and color retention in broccoli over 72 h. RAA degradation in misted and nonmisted samples and total chlorophyll degradation in nonmisted broccoli samples exhibited first order kinetics. Peroxidase activity was significantly greater in nonmisted broccoli stalk. No differences were found for AO activity or Instron values. Misting was found appropriate for postharvest storage of broccoli.

RAA content was measured in broccoli spears packaged in polymeric film and nonpackaged during 96 h (10$\sp\circ$C). CO$\sb2$ and O$\sb2$ concentrations within packages monitored by gas chromatography were 8% and 10%, respectively. RAA retention was significantly greater in packaged samples over 96 h. RAA destruction in nonpackaged broccoli exhibited first order kinetics. Total chlorophyll and color retention were significantly greater in packaged broccoli. No significant differences were found for moisture, AO and peroxidase activities, or texture. High CO$\sb2$ MAP of broccoli (10$\sp\circ$C) was found acceptable for postharvest storage.

RAA content was measured in broccoli spears packaged in polymeric film and nonpackaged during 96 h storage under environmental conditions (20$\sp\circ$C). CO$\sb2$ and O$\sb2$ concentrations within packages monitored by gas chromatography were 8% and 2.5%, respectively. RAA retention was significantly greater in packaged samples over 96 h. RAA destruction in nonpackaged broccoli exhibited first order kinetics. Peroxidase activity and Instron values were significantly lower, and chlorophyll retention was significantly greater in packaged broccoli. No significant difference was found in total microbial growth trends. MAP recommended under appropriate temperature and relative humidity conditions.