Updating present mango storage parameters.
Kruger F. J., Robertson A., Malumane R., Freeman T.
Author Affiliation: Institute for Tropical and Subtropical Crops, Private Bag X11208, Nelspruit 1200, South Africa.
: 110-115
Abstract : A study was conducted to upgrade current mango storage parameters and to develop new operating procedures where the need exists. During the last season, samples of cultivars 'Tommy Atkins', 'Kent', 'Sensation' and 'Heidi' were obtained from the Hoedspruit and Onderberg areas (South Africa) during both the early and late seasons and stored under a range of storage conditions. The latter conditions included delivery air temperatures ranging between 4 and 18°C, relative humidities between 75 and 95%, and windspeeds between 0.5 and 6 m/s. An elaborate set of step down temperature regimes were also evaluated. In addition to the above, a number of ad hoc trials were conducted. These included experiments on the effect of soaping on the manifestation of external chilling injury. Also included were trials aimed at establishing the potential of stepping up the storage temperature during storage. This was done in an attempt to develop a method to land fruit with better external colour without a significant loss in firmness. The results firstly indicated that packinghouses should be aware that the use of soap might increase the prevalence of external physiological disorders under certain conditions. Further research on this topic is required. Although the temperature trials confirmed the absence of scalding injury in early 'Tommy Atkins', 'Kent' and 'Sensation' when stored at delivery air temperatures approaching 8°C, poor degreening may necessitate export at a higher temperature if external colouration is important. In the case of 'Keitt' and 'Heidi', chilling injury was only eliminated at storage temperatures approaching 12°C and a storage temperature of 11°C is recommended for the early season. It is advocated that fruit be cooled to the holding temperature as soon as possible after palletizing without employing intermediate steps. It is further suggested that current cold room air flow rates and relative humidities be retained for now. Future laboratory based research should include trials aimed at identifying appropriate alternatives to soap. As the present step-down temperature trials entailed the moving of boxes of fruit between cold rooms, it would be worthwhile to establish whether the surface scalding recorded on these fruit is ascribable to the temperature stepdown procedure or condensation during transfer. If the latter applies, it may be worthwhile to compare the effect of the conventional cold chain with direct container loading. Packinghouse based studies must include trials aiming to quantify the effect of stepping fruit through the palletizing room. The potential of Filacell technology recently installed in an avocado packinghouse should also be gauged. The potential use of controlled atmosphere in combination with higher temperature regimes is another research option. Finally, the timing and increments at which the maturity related storage temperature is to be lowered is to be refined.