Effects of hot water treatments and storage temperatures on the ripening and the use of electrical impedance as an index for assessing post-harvest changes in mango fruits.
Nyanjage, M. O., Wainwright, H. and Bishop, C. F. H.
Annals of Applied Biology. Volume 139, Issue 1, 2001, Pages 21-29.
2001
บทคัดย่อ
The effects of hot water treatment (hwt) and storage temperature (4, 13 or 22 deg C) on the quality and impedance of outer and inner mesocarp of mango cv. Tommy Atkins were assessed in two experiments during storage, impedance being a potential non-destructive measure of tissue damage following heat treatment. Fruits were subjected to equivalent heat units at 36.5 deg C for 60 min plus 46.5 deg C for 43 min or 46.5 deg C for 90 min by hwt on the assumption of cumulative heat effects and a base temperature of 12-13 deg C. Fruit reflectance decreased, whereas, chroma and hue angle increased over storage time and also with increase in storage temperature. The yellow colour increased with a rise in storage temperature in hot water treated mangoes. Soluble solids content of mangoes held at 22 deg C was highest at 5 days of storage, but decreased subsequently over storage time. Impedance of all fruits decreased with increase in frequency, storage temperature and time in store. The impedance of hwt mangoes was lower than that of non-hwt fruits 8 h after immersion, but recovered almost to control levels on day 5 at 4 or 13 deg C, but decreased gradually after 5 days at 13 deg C. Impedance of all mangoes stored at 22 deg C decreased continuously during storage. Impedance was higher in the inner mesocarp than outer pulp. Impedance of hwt fruits was poorly correlated with soluble solid content and chroma but well correlated with reflectance of fruit pulp at 22 deg C. Changes in impedance of mangoes are discussed in relation to physiological and biochemical changes that occur during heat treatment and storage.