Postharvest Conditions Inducing the Occurrence of Concavities on Scales of Garlic Bulbs

Abstract

Curing and long-term storage are essential postharvest treatments for the year-round shipping of garlic bulbs. We examined the postharvest conditions that induce concavities on the scales of long-term-stored garlic bulbs using 'Fukuchi White', a major cultivar in Japan. Bulbs were cured by a tempering method which consisted of heating at about 34°C during the day and nonheating at night under forced ventilation, and were stored at -3, -2, and -1°C under standard and low-humidity regimes for a maximum of 10 months. Some bulbs stored at -3°C had concavities on the scales, but few bulbs stored at -2 and -1°C had concavities regardless of the storage humidity. Bulbs were cured by continuous heating at 33°C or by the tempering method, and were stored at -3, -2, and 0°C for a maximum of 8 months. The mean temperature during tempering was about 30°C. After curing by continuous heating at 33°C, most of the bulbs stored at -3, -2, and 0°C had concavities, but few bulbs stored at -2 and 0°C after curing by tempering had concavities. Severe concavities were observed on the bulbs stored at -2 and -3°C after curing by continuous heating at 33°C. These results suggest that curing at a high temperature and storage at a low temperature induce the occurrence of concavities, and that the curing condition markedly affects the occurrence of concavities when bulbs are stored at -2°C, which is the current storage temperature used for the year-round shipping of garlic bulbs in Aomori Prefecture. This method of curing by tempering combined with storage at -2°C may provide high-quality garlic bulbs throughout the year.

Post-harvest Techniques for Practical Use Regarding a Steady Year-round Supply of Garlic Bulbs

“…This suggests that the curing temperatures used in the tempering method and continuous heating affect the incidence of concavities during storage. Therefore, Yamazaki et al (2014) conducted a test on curing methods and the occurrence of concavities on scales. The test section created a 33°C continuous heating zone where 33°C hot air was ventilated all day, as well as a tempering method zone where 34°C hot air was ventilated during the daytime, with ambient temperature air being ventilated at night.…”