Abstract
The respiration rate, the chemical components including ascorbic acid and sugar, and the quality stability of Welsh onion (A llium fistulosum L.) harvested in summer (July, '95), autumn (November, '95), winter (January, '96) and spring (April, '96) were investigated during storage at room temperature or at 15°C. A nearly second order regression equation (Y = a + b * T+c * T2) with high relative coefficient (R = 0.987 - 0.991), was established between respiration rate (mgCO2 /kg/hr) (Y) and temperature of Welsh onion (T). At the same temperature, Welsh onions harvested in the winter season showed a higher respiration rate than those harvested in the summer season. In the Welsh onion harvested in the summer and stored at room temperature conditions, ascorbic acid content decreased markedly and the score of leaf tip withering increased. These results indicate that Welsh onions harvested in the summer season and stored at room temperature do not retain good quality. Ascorbic acid and sugar contents in Welsh onion harvested in winter were maintained for 6 days, suggesting that good quality is retained during storage room temperature. On the other hand, summer season Welsh onions stored at 15°C indicated much better quality stability than those of the winter season. There was a correlation between the respiration rate of Welsh onions and quality stability, meaning that the lower was the respiration rate, and the higher was the quality stability.
