Limitation and good practices for breakage of cold chain on cos lettuce (Lactuca sativa var. longifolia)

¹ Chiang Mai University, Faculty of Engineering, Department of Mechanical Engineering, 239 Huay Kaew Road, Muang District, Chiang Mai 50200, Thailand
² Chiang Mai University, Faculty of Agro-Industry, Division of Food Engineering, Chiang Mai 50100, Thailand
³ Ministry of Higher Education, Science, Research and Innovation, Postharvest Technology Innovation Center, 238 Thanon Si Ayutthaya, Thung Phaya Thai, Ratchathewi, Bangkok 10400, Thailand
⁴ Chiang Mai Royal Project Produce Center, The Royal Project Foundation, 243 Moo 3 Muang District, Chiang Mai 50100, Thailand
⁵ Chiang Mai University, Faculty of Agriculture, Postharvest Technology Research Center, 239 Huay Kaew Road, Muang District, Chiang Mai 50200, Thailand

^* Corresponding author: damorn.b@cmu.ac.th

Abstract

An effect of breaking the cold chain on cos lettuce (Lactuca sativa var. longifolia) had been studied in this research. Cos lettuce was taken under cold chain system at 4°C. Imitating the exposure to high temperature in hot country, cos lettuce was put out in the 25, 30, 35,and 40C atmosphere for 15, 30, 45 and 60 min. Product life, weight loss percentage, change of colour and chlorophyll content were measured to investigate quality degradation of cos lettuce. The limitation and good practices cos lettuce which had to go through cold chain breakage were acquired. From the results, it is recommended that cos lettuce should not exposed to temperature higher than 25C for longer than 30 min in order to maintain acceptable quality and freshness close to absolute cold chain, considered from degradation of weight, colour and chlorophyll. Degree of temperature had influences on degrading levels of cos lettuce. Exposing to temperature higher than 35C would degrade its quality and freshness and reduce storage life and should be avoid in any cases.