Effects of harvest season on respiration rate, chemical composition and quality stability of broccoli (Brassica oleracea L. italica)
2008
Ikeda, H.(Fukuoka-ken. Agricultural Research Center, Chikushino (Japan)) | Fujise, T. | Miyagi, K. | Ibaraki, T. | Ohta, H.
To study the preservative property of various shredded vegetables treated by steam heating, cabbage, cucumber. The respiration rate, chemical composition in terms of reduced ascorbic acid and total soluble sugar, and quality stability of broccoli harvested in autumn (November), winter (January) and spring (April) were investigated during storage at room temperature or 15degC. A nearly second-order regression equation (Y=a+b*T+c*T**2) with a high relative coefficient (R=0.989-0.996) was established for the respiration rate (mg CO2/kg/hr) (Y) and temperature (degC) (T) of broccoli. At the sametemperature, broccoli harvested in winter showed a higher respiration rate than that harvested in autumn. Broccoli harvested in winter had two times as much total soluble sugar content as that harvested in autumn or spring. For broccoli harvested in autumn and stored at room temperature, its reduced ascorbic acid, total soluble sugar and chlorophyll contents decreased markedly with floret yellowing. These indicate that broccoli harvested in autumn and stored at room temperature does not retain good quality. The reduced ascorbic acid and total soluble sugar contents of broccoli harvested in winter remained unchanged for 6 days, suggesting that the broccoli retains good quality during storage at room temperature. Similarly, broccoli harvested in winter and stored at 15degC showed had much better quality stability than broccoli harvested in the other seasons. For the same harvest season, the quality of broccoli was successfully maintained during storage at low temperature. Moreover, correlations among the respiration rate, chemical composition and quality stability of broccoli were observed, that is the lower the respiration rate, the higher the reduced ascorbic acid and total soluble sugar contents and the higher the quality stability.
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