Flavor and Quality Changes in Sweet Onions During Storage at Room Temperature

Flavor and quality parameters of onions (Allium cepa ‘Walla Walla Sweet’) were monitored for up to 7 weeks following harvest. Shelf‐life of bulbs harvested earlier in the season was shorter than that of onions harvested 3 weeks later. Soluble solids of inner scales and average pyruvate, 3,4‐dimethyl thiophene and disulfides content increased during the 4 week shelf‐life at 22C of the onions harvested in June. These increases resulted in the final contents to be comparable to those of onions harvested on July 2, 1992, which were relatively stable. The pyruvate concentration was comparable to that of a mild, nonpungent onion. Correlations between pyruvate, thiophene and soluble solids were not significant. The relationship between 3,4‐dimethyl thiophene, disulfides and onion flavor is discussed.