Physicochemical, shelf-life and sensory characteristics of conventional and organic sugar-loaf pineapples stored at two temperatures

Abstract

The pineapple (Ananas comosus) is a tropical plant with edible fruit of the Bromiliaceae family, having several different cultivars or types. They are non-climacteric fruits, i.e. they must be harvested ripe because it will not continue to ripen once harvested. Fresh pineapple is an excellent source of vitamin C. The sugar-loaf pineapple is smaller in size than other varieties, stay green even when ripe and feature a brighter pearl white fruit, with a soft edible core. There is a big demand for organically produced sugar-loaf pineapples in Europe. At this stage, however, sugar-loaf can only be air-freighted. Studies have indicated that organically grown sugar-loaf is stronger and has a longer shelf life that could be suitable for export market. This makes exporting the sugar-loaf pineapple by sea seemingly possible under the right conditions of temperature and humidity. The main objective of this research was to assess the possibility of sea-freighting organic sugar-loaf pineapples by comparing the shelf-stability of conventional and organic pineapples. Conventional and organic grown sugar loaf pineapples of 150 days (8 month age of forcing) and age 135 days (11months age of forcing) respectively were studied. Conventional pineapples were harvested from Albe Farms in the Eastern region and organic pineapples from Ali farms in the Central regions of Ghana. Three batches of the pineapples were supplied. Physical characteristics (fruit weight, fruit length, crown weight, crown length, crown to fruit ratio, core diameter and translucency) were determined. Chemical properties (pH, brix, titratable acidity and vitamin C) were also determined. These properties were assessed at a baseline (after harvest) and after storing for 14 days at 1 °C or 8 °C. Generally, organic pineapples had large fruits compared to conventional pineapples. The conventional pineapples had a short shelf-stability than organic pineapples. The pH values for the organic pineapples was lower than the conventional pineapples while the acidity of the organic sugar-loaf pineapples was higher than the conventional. The vitamin c content for the baseline organic sugar-loaf pineapples varied from 25.22 to 33.02 mg/100 ml and that for conventional pineapples 19.69-23.66 mg/100 ml. Generally, conventional sugar-loaf stored at 8°C attained a higher translucency (50-75%). Although Vitamin C was generally lower after storage (compared to the baseline), organic sugar-loaf stored at 1°C and 8°C had higher Vitamin C compared to the conventional pineapples. Lower acidities were also observed in both types of sugar-loaf pineapples after storage. Organic sugar-loaf pineapples stored at 1°C and 8°C largely had 25-50% translucency after storage. Only 16% and 8% of the organic fruits recorded 50-75% translucency for after storing at 1°C and 8°C correspondingly. Conversely, a majority (52.3%) of conventional sugar-loaf pineapples at 1°C recorded 50-75% translucency. These results suggest that the organic sugar-loaf pineapples will have a longer shelf-life under refrigerated conditions. Using proper handling and packaging methods and the right conditions (1°C and 8°C), it is may be possible to sea-freight organic pineapples to Europe because it can thrive at both temperatures without spoilage