Enzyme activity, sugar composition, microbial growth and texture of fresh Barhi dates as affected by modified atmosphere packaging.

Abstract

The effects of modified atmosphere packaging (MAP) on various physicochemical quality attributes of fresh Barhi dates at the Khalal (yellow) stage were studied. Polypropylene (PP) and polyethylene (PE) plastic with varied perforation sizes (0, 50, 100 and 150µm) were evaluated for storage of date fruits at temperatures of 1, 5, 15 and 25°C up to 45days. MAP showed significant effects on fruit quality. PP date packages perforated with 150-µm perforations and stored at 5°C had the lowest acidity and microbial load. Dates packed in PE exhibited higher pectin methylesterase (PME) and polyphenol oxidase (PPO) activities than dates packed in PP. Dates stored in nonperforated packages had the highest PME, PPO and invertase activities. The maximum fructose and glucose contents were observed in PP-packaged dates stored at 15°C. Analysis of the interactions of several MAP variables revealed temperature as the major variable controlling the quality of dates. The findings showed that MAP can be effectively employed to preserve the quality and improve the shelf life of Barhi dates using PP with 150-µm perforations as the packaging material during storage for 2weeks at 5°C.