Influence of various storage conditions on rind breakdown and quality parameters in tangelo (Citrus reticulata Blanco x Citrus paradisi Macf.)

Abstract

Minneola tangelos were obtained from different production areas in two seasons (1996: Western Cape and Swaziland, 1997: Western and Eastern Cape), and stored at two different temperature regimes simulating the shipping and storage treatments of fruits for overseas markets to determine if storage regimes have an influence on quality parameters. Samples were taken every two weeks and quality parameters such as fruit shape index, mean rind thickness, % juice, %TSS, and % acid were determined. An experiment to determine weight loss during storage time was done at the same time. Main significant differences across all the parameters were observed between fruits from the different production areas, while fruit shape, % juice, and occurrence of rind breakdown did not differ significantly. In 1996, the weight loss developed in storage only showed a significant difference after 8 weeks in storage. In 1997, there was no clear pattern, but the interaction between producers and storage temperatures differed significantly. Focusing on the producer from the Western Cape, there was a significant difference between storage temperatures, confirming that citrus fruits stored at a higher temperature (11°C) will loose moisture faster than those stored at a lower temperature (4.5°C). Even with the higher moisture loss, there were no differences between the fruit stored at the different temperatures, apart from the difference between the producers indicating that changes in quality of 'Minneola' fruit are mainly determined by the producers and apparently to a lesser extent by storage temperatures of 4.5°C and 11°C. With the high rate of over-maturity developing in storage, it is possible that the fruit might have been stored too long. Therefore, the marketing period for soft citrus types is apparently too long and problems with physiological ageing can be abundant at this storage length.