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Received Nov 5, 2017; Accepted Jan 4, 2018
This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
1. Introduction
Cucumber is a nonclimacteric fruit vegetable that contains more than 90% water. The principal factor affecting fruit quality during transportation, storage, and marketing is often excessive moisture loss [1]. Besides weight loss resulting in a lower price when sold on a weight basis, postharvest moisture loss also reduces fruit quality through loss of glossiness, shriveling, and increased susceptibility to postharvest pathogens [2, 3].
Fruits and vegetables have diverse adaptive mechanisms to control moisture loss [4]. Cuticular wax is a major barrier restricting moisture transfer. It has been reported that a high content of the cuticles was correlated with moisture retention capacity of plant tissue [5]. Immature fruits typically have a relatively thin cuticle and the cuticle is often at least partially removed during washing. Postharvest moisture loss of such commodities can be reduced by coating with a wax after harvest [6]. In addition, wax coatings may result in the development of a modified atmosphere within coated products, slowing respiration and other physiological processes and possibly improving the quality and extending shelf life [7, 8]. Such practices have been used successfully in fruits and vegetables such as tomato [9], orange [10], and avocado [11].
Previous studies have evaluated the effects of wax coatings on postharvest moisture loss at a specified controlled temperature [7, 12]. However, temperature is the most critical factor influencing the rate of moisture loss. Thus, the objective of this work was to evaluate the influence of different temperatures on moisture loss of waxed cucumbers. A kinetic model was also developed to investigate the relationship between temperature, wax coating, and moisture loss. The shelf life of cucumber under different temperatures was also predicted based on the kinetic model.
2. Materials and Methods
2.1. Materials and Wax Treatments
Commercially ripe cucumbers (Cucumis sativus L., cv. Jinglv) were harvested in the local orchard. All cucumbers were grown under the same environment and harvested at the same time for subsequent experiments. Cucumbers were selected for uniformity in appearance and size (