2.2.1. Hot water blanching (HWB)
Hot water blanching was carried out by immersing stem lettuce
cubes (8 8 8 mm) into 95 C distilled water in a stainless steel
pan heated by an induction cooking plate. The weight ratio of stem
lettuce cubes and distilled water was 1:2. The temperature inside
the samples was measured with a thermocouple and blanching
was stopped when the temperature of the stem lettuce cubes
reached 95 C within 2 min and held for 2 min. After the pretreatment,
the samples were cooled using a fan until there was no visible
water on the surface of the samples.