Detecting Freshness of Fruit and Vegetable Without and With Edible Protein-Based Foil

In recent years, food packaging has become essential, both for producers and consumers. The increasing use of food packaging has a major impact on food quality, but also on the environment. Ripening, freshness and quality of fruit and vegetable from field to the table became increasingly demanding in the food industry. The classical approach to maintain the freshness of fruits and vegetables after cutting is based on use of plastic foils, which is not eco-friendly and increases plastic waste. The purpose of this study is to explore the possibility of maintaining the freshness of chopped and cut fruits and vegetables using materials based on biopolymers such as protein-based films. Comparing to the most used films and coatings for food packaging, plant protein-based films are edible, biodegradable, vegetarian- and eco-friendly. Non-destructive method used for characterization of freshness during time was electrical impedance spectroscopy connected to the transmission line-based platform. The aim of this work was to correlate the bioelectrical impedance variation with ripening and dehydration of fruit and vegetables (pear and zucchini) without and with a wrapped protein-based films. The impedance of the samples on the microchips was measured at frequency sweeps ranging from 2 kHz to 200 kHz for 39 points. The results demonstrated that the bioimpedance increased with the progresses in fruits and vegetable ripening. For a better understanding of the underlying processes, we provided an equivalent electrical circuit with physical interpretation of circuit elements. Changes of model parameters with time showed excellent correlation with fruits and vegetable ripening.