Biochemical changes in chaenomeles fruits and fruit juice during ripening and storage

In this paper, studies on the changes in characteristics and chemical composition of Japanese quince (Chaenomeles japonica) fruits and fruit juice during fruit ripening and storage are reported. Juice was extracted from unripe, mature and stored fruits, respectively, and pH, density, viscosity, turbidity, content of soluble and insoluble solids, titratable acidity and content of vitamin C and phenols were analysed. Fruit biochemistry was clearly influenced by genotype and site of cultivation of plants. Ripening was associated with an increase in density, soluble solids, titratable acidity and content of vitamin C in the juice. During storage at 1 °C and 5 °C, respectively, the general tendencies for changes in fruit biochemistry were similar for all genotypes analysed. The characteristics of the fresh fruit were well preserved at 1 °C, even during two months of storage. However, after three months a significant loss in juice yield was observed. This was accompanied by browning of the fruit skin, an increase in turbidity of the juice, changes in the content of vitamin C and a modification of aroma. The fruits kept at 1 °C and 85% relative humidity could be stored for a maximum of nine weeks without significant loss in quality. At 5 °C and 80% relative humidity, the corresponding storage period decreased to four weeks