EFFECTS OF POLYETHYLENE PACKAGING ON THE QUALITY OF HEAT TREATED TOMATO FRUITS

Abstract

Packaging affects the overall quality, shelf-life and consumer acceptance of fresh produce. Correct prestorage heat treatment controls decay. The objective of this work was to determine the best polyethylene (PE) thickness for storage of tomatoes at different maturity stages under two temperatures. ‘Roma’ tomatoes at mature-green (MG), breaker, turning and pink maturity stages were subjected to hot air treatment at 46°C for 1 h, packed into different grades of PE and stored at 12 or 28°C. The fruits were assessed for ripening and disease incidence at 8 and 15 days of storage. Results showed advancement in colour development in all stages of fruits and in all thicknesses of PE, but the advancement were not statistically significant in fruits stored at 12°C except in turning fruits while it was significant in all at 28°C. The greatest advancement was by MG in 2.5 µm thick polyethylene which ripened beyond light red while the least progress was by the same mature-green in 40 µm thick PE. As the thickness of packaging material increased from 2.5 to 40 µm, colour development reduced. Titratable acidity (TA) increased in all the packages except turning fruits packed in 2.5 and 10 µm which had reduced TA, indicating more ripening in those fruits. Total soluble solids (TSS) increased in pink fruits at 12°C but decreased in the same pink fruits at 28°C. Greatest increase in TSS occurred in turning fruits in 5.0 µm PE. Disease occurred in all maturity stages of fruits in all packages but was lower at 12 than at 28°C. Disease was lowest among MG fruits at both temperatures except fruits in 40 µm thick PE at 28°C, and highest in pink fruits in 10 µm at 12°C and in 40 µm thick PE at 28°C. Tomatoes, in different ripening stages should be packaged in the appropriate PE thickness that best preserves their quality.