The effect of various storage temperatures on peroxidase activity and protein PAGE gel electrophoresis in ‘Queen’ pineapple fruit

SummaryMature ‘Queen’ pineapple fruit were stored for 30 days at various temperatures and afterwards examined for internal quality. A storage temperature of 8°C is at present generally accepted as the optimum. It was found that peroxidase (PO) activity is correlated with storage temperature and the appearance of storage injury symptoms. High storage temperatures of 10°C, 12°C and 16°C resulted in a high PO activity with internal browning of the core and pulp whereas temperatures of 2°C, 4°C and 6°C resulted in a low PO activity and white watery pulp. To verify these results, polyacrylamide gel electrophoresis was carried out with the proteins in the fruit. The difference in the two extreme temperatures of 2°C and 16°C resulted in a high intensity of high molecular mass proteins at 2°C and an increase in intensity of low molecular mass proteins at 16°C. There is a distinct “change over” of these protein band intensities at 8°C to 12°C. It is presumed that the correct storage temperature will be within these two limits.