Evaluation of humidity retention in refrigerator storage systems by application of a food simulant

Abstract

Vegetables lose quality after harvest mainly due to water-related weight loss. In households, vegetables are usually stored in refrigerators, typically providing temperatures from 0 – 14°C and relative humidity ranges from 20 – 100 %. Weight loss is related to the storage humidity conditions. As a consequence, storage systems providing humidity-controlled conditions are decisive for the evaluation of the freshness performance of refrigerators. To evaluate the impact of storage zones on the fresh weight loss of stored goods, the international standard IEC 63169:2020 “Electrical household and similar cooling and freezing appliances – Food preservation” has been released. It uses a cellulose based food simulant, overcoming influences of cultivar and post-harvest handling conditions of real vegetables. This publication compares the weight loss of spinach and the food simulant in chilled storage conditions at three ranges of relative humidity. Different cultivars and pre-handling modifications of the spinach were used to determine the impact of product parameters on weight loss. A round robin test was performed to analyse the applicability of the IEC 63169:2020. The results prove the applicability of the standard to analyse the impact of humidity controlled storage on weight loss: It is shown that pre-handling has an impact on spinach's weight loss, which is overcome by the food simulant. For all tested conditions, the weight loss behaviour from spinach and the food simulant is correlating in test durations up to 72 h. The round robin test shows that the test method of IEC 63169:2020 provides repeatable and reproducible results.