EFFECT OF HOT WATER IMMERSION ON PEEL COLOR OF PEARS AND ON WHITE ROT CAUSED BY BOTRYOSPHAERIA BERENGERIANA

Abstract The effectiveness of hot water immersion (HWI) on peel color and the control of white rot caused by Botryosphaeria berengeriana on wound-inoculated European pears, cv. La-France, were investigated. After HWI at 40, 45, 48, 50, 52 and 54C for varying immersion periods, the pears were held at 20C, ≥ 90% RH (simulated retail conditions). The peel color (L*, a*, b*) was determined before and after HWI treatment. The dominant role of L* suggested that peel darkening was the major factor in color change of the HWI treated pears. The L* value of 54 was judged as the border line for acceptability and less than 51 resulted in browning. Similarly the critical points for a*, b*, chroma, hue and ΔE* were found to be −6, 34, 35, 100, and 8, respectively. Disease incidence recorded 7 days after treatment revealed that High Temperature Short Time (HTST) treatment of 54C for 3 min reduced incidence about 85% with good retention of color. Both temperature and immersion period are to be carefully selected to prolong shelf-life and retain the peel color quality of 'La-France'pears.