Effect of hot water treatment on leaf extension growth,fresh weight loss and color of stored minimally processed leeks

Freshly harvested leeks (Allium porrum L.) were heated by immersion in water at 50, 52.5, 55 or 57.5 °C for 0–60, 0–35, 0–20 and 0–15 min, respectively. After hot water treatment, leeks were cooled in water at ambient temperature for 10 min and then cut at 22 cm from the compressed stem of the root base, weighed, had color measured and stored at 4 °C for 9 days. Untreated stalks (without immersion in a hot water bath) were used as controls. Hot water treatments at 50 °C for 40–60 min, 52.5 °C for 25–35 min, 55 °C for 17.5–20 min and 57.5 °C for 10–15 min efficiently controlled postharvest leaf extension growth in stalks stored for 9 days. However, treatments that controlled leaf extension growth showed fresh weight loss significantly higher than the control. There was only a slight effect of heat treatment on color attributes of stored minimally processed leek.