1985 Volume 54 Issue 2 Pages 257-264
The effect of fluctuating temperature (square-wave form) on the quality of asparagus, broad bean, edible podded pea, shallot, shii-take mushroom, enoki-take mushroom and ‘Muscat of Alexandria’ grape was investigated, in comparison with those held at a steady temperature. In the fluctuating temperature treatment, materials were kept under the following conditions: fluctuation amplitudes of ±5°C, ±3°C and ±1°C for periods of 12-hours and 6-hours, the standard temperature being 6°C.
In asparagus, deterioration of appearance, increase in hardness and decrease of ascorbic acid content were hastened as fluctuating amplitude widened. The fluctuating temperature produced a reduction in quality of broad bean seeds rather than on visual freshness of the pod; browning of the hilum portion was promoted even with an amplitude of ±1°C. Fluctuating temperature did not have so much influence on the deterioration rate of edible podded pea. However, adverse effects of fluctuating temperature were observed in shallot, shii-take and enoki-take, and their deterioration rates were higher under conditions of fluctuating temperatures. While the browning of stems and pedicels of Muscat of Alexandria′ grape was slightly accelerated with fluctuating temperatures, little differences in deterioration rate were found between clusters stored at fluctuating temperatures and those stored at standard temperature of 6°C.
From the results above, it is evident that the fluctuating-temperature tolerance of asparagus, broad bean, shallot, shii-take and enoki-take is low and that a steady low temperature is required to retain quality during low temperature storage. The fluctuating-temperature tolerance of edible podded pea and ‘Muscat of Alexandria’ grape is slightly higher than that of the above products and temperature fluctuation during storage is tolerated to a certain extent.