No abstract

A study was undertaken to compare the postharvest properties of organically and conventionally grown bananas. The effects of ethrel treatment on the skin colour of organic and non-organic bananas (Musa AAA group Cavendish subgroup, Robusta) were determined during ripening at 22-250C. In addition, pulp temperature, impedance (at 100Hz, 500Hz, I kHz, 10kHz), gravimetric and volumetric pulp: peel ratios, fruit density, total soluble solids (TSS) and major (N, P, K, Ca and Mg) minerals of ripe fruit were also compared for organically and conventionally grown bananas. Organic bananas ripened faster than non-organic bananas as measured by peel colour change (reflectance, chroma and hue angle). Hedonic scale values showed that ethrel treatment promoted uniform skin change from green to yellow. Visual colour values had strong positive correlation against reflectance, chroma or hue angle, but was more closely related to hue angle. Organic and non-organic bananas had no significant difference in TSS contents. Impedance decreased with rise in frequency and pulp temperature and showed strong negative correlation against reflectance, chroma and hue angle of organic and non-organic banana at I 00 Hz. Ripe nonorganic bananas had both higher gravimetric pulp: peel ratio and impedance compared with organic fruits. In all fruits, the peel had higher N, P, K, Mg and Ca than the pulp. The peel of non-organic fruits had higher N and lower P contents than organic fruits. Differences in mineral content between the pulp of organic and non-organic fruits were much less than those between the peel. This study shows that production methods of bananas has a significant influence on the postharvest behaviour of bananas and this in turn must influence their subsequent management in order to optimize quality for the consumer.

SummaryThe effects of hot water treatment and storage temperature (4°C, 13°C or 22°C) on the quality and impedance of outer and inner mesocarp of mango 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°C for 60 min plus 46.5°C for 43 min or 46.5°C for 90 min by hot water treatments (hwt) on the assumption of cumulative heat effects and a base temperature of 12–13°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°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°C or 13°C, but decreased gradually after 5 days at 13°C. Impedance of all mangoes stored at 22°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°C. Changes in impedance of mangoes are discussed in relation to physiological and biochemical changes that occur during heat treatment and storage.

No abstract

No abstract