Time-temperature Tolerance for Keeping Quality of Fresh Fruits and Vegetables

Part III. Time-temperature tolerance of spinach and celery

Abstract

We have investigated the time-temperature tolerance of various fresh fruits and vegetables during low temperature storage at above freezing temperature in relation to their marketing qualities. This report describes the effects of various temperatures and the fluctuation on the quality of spinach and celery during the storage.
1. It was recognized that freshness, leaf color and ascorbic acid content of spinach were strongly influenced by storage temperatures. The period of keeping marketing quality of stored spinach was about 35 days at 1°C, about 15 days at 6°C, and about 3 days at 20°C. The fluctuation of the temperature during storage accerated the deterioration of the quality, and it depended on the maximum temperature of the fluctuation. Ascorbic acid content of stored spinach decreased rapidly at 20°C but decreased gradually at 6°C and 1°C, The fluctuation of the temperature during storage resulted in a rapid decrease of ascorbic acid.
2. In order to keep freshness and higher content of reducing sugar in stored celery, the constant low temperature of 1°C was required immediately from the harvest day. The good quality was kept for 7 weeks at 1°C, for about 25 days at 6°C and for about 5 days at 20°C. The patterns of gas chromatogram of the volatile compounds of celery were significantly different between 20°C or 6°C-treatment and 1°C-treatment.
3. Thus, it was shown that for the keeping quality of spinach and celery they should be kept at nearly 1°C immediately after harvest and during the subsequent storage.