Prediction of plastic film thickness based on gas permeability and validation with ‘Kyoho’ table grapes for optimal modified atmosphere packaging

Abstract

Modified atmosphere packaging (MAP) storage has become a useful technique for extending the shelf life of fruit and vegetables. However, the success of MAP depends on many factors, including types of fresh products, storage conditions, and the characteristics of the packaging films. To achieve the optimal gas composition in the package headspace and improve the postharvest quality of fresh produce, the packaging film with appropriate barrier properties needs to be selected. This study aimed to predict the film thickness by applying produce respiration rate and package film permeability data measured in given product weight and storage conditions. An available film (eg, 25‐μm‐thick low‐density polyethylene) was used to pack fresh produce, and the respiration rate of fresh produce and in‐package O2 and CO2 concentrations at steady state were measured. Permeability of the film was calculated based on mass balance, and the thickness of the film could be predicted if the recommended target O2 and CO2 concentration was obtained from the literature. To validate the predicted thickness value, an experiment was conducted by packaging fresh table grapes in bags of the predicted thickness. The effect of packaging with different film thicknesses on the quality of the fruit was determined. The results showed good agreement between the predicted and the experimental in‐bag O2 and CO2 concentrations, and the MAP with predicted thickness (90 μm) film was more effective in maintaining postharvest quality of grapes during low‐temperature storage than the thinner films (30 and 60 μm) and the control.

The Postharvest Quality of Fresh Sweet Cherries and Strawberries with an Active Packaging System

“…The O 2 concentrations inside all the Life + packaged strawberries decreased rapidly during the initial days of storage, and a steady-state concentration was established between the second and third day. According to Chen et al [26], MAP packaging takes approximately three days to generate a steady-state atmosphere passively through produce respiration. In this study, the O 2 concentration fell from 21 kPa to a steady-state value of about 12 kPa, whereas the CO 2 concentration hovered around 10 kPa in both treatments following an initial rapid increase in CO 2 concentration from 0 kPa to 6 kPa inside all the packages during the first day.…”