The Future of Postharvest Preservation: Chitosan and?Beyond

Freshly picked fruits and vegetables contain a large percentage of water and continue to metabolize after harvest, making them more susceptible to spoilage fungus, loss and wastage. Edible coatings can help reduce waste, protect the environment and improve consumer health because they are made from naturally occurring renewable resources. Edible coatings, such as chitosans, form a thin layer around fresh produce, providing protection, extending shelf life, controlling the ripening process and preserving the nutritional properties of the coated product. This article explores the potential of chitosan and other emerging technologies in postharvest preservation and discusses how they may change the way to store and transport fresh produce in the future. Innovative Strategies for a Greener?Future The world?s rapidly growing population threatens global food security and the efficient production of sufficient quantities of quality food. Fruits and vegetables help reduce the incidence of malnutrition and are an essential part of a healthy human diet. Because they are highly perishable, they must be handled with the right technology to ensure quality and extend shelf life after harvest. But over time, quality attributes such as weight, nutritional value, flavor, color and bioactive compounds decline due to senescence. What?s more, plant diseases cost money every year, reduce crop productivity and quality, and lead to higher food prices and global food insecurity. Especially in the context of limited natural resources and climate change, minimizing the loss and waste of fresh fruits and vegetables can help relieve pressure on food production systems. Furthermore, increased consumer awareness of pesticide residues on food has motivated the search for natural and environmentally friendly optional strategies to control pre- and postharvest diseases. An emerging technology for protecting fruits and vegetables from postharvest spoilage fungi is the use of edible coatings with antifungal activity. Coatings can change the composition of the atmosphere around the fruit, sealing off gas exchange such as carbon dioxide, ethylene, and oxygen involved in respiration. A variety of edible coatings have been shown to protect the nutritional content of the fruit more effectively than traditional packaging. Marche Polytechnic University, (Ancona, Italy) published a study in 2022 discussing the latest research on the application of chitosan and other edible coatings. Below is a summary of the alternatives. Chitosan There are many edible coatings available, the most common of which is chitosan. It is the second most abundant polysaccharide in nature after cellulose and is found in the exoskeletal structure of marine invertebrates, insects, fungi, yeasts, and algae.? Chitosan is one of the most widely used edible coatings due to its biocompatibility, biodegradability and bioactivity, as it is a powerful material that can be applied in human medicine, cosmetics and agriculture.? When applied to fruits and vegetables, chitosan can induce host defense. It has antimicrobial activity against decay-causing fungi and forms a semi-permeable film on a treated surface.? For post-harvest preservation of fresh fruits and vegetables, this edible coating is widely used. In recent years there has been a growing body of scientific literature on chitosan-based edible coatings. This can be explained by its importance in crop protection as a natural fungicide and plant defense enhancer, and by its use to extend the shelf life of a wide variety of fruits and vegetables around the world.? By 2014, chitosan hydrochloride was approved by the European Union as one of the first active ingredients for crop protection.? Chitosan has been shown to inhibit a number of postharvest fungal pathogens and has broad-spectrum antimicrobial activity. Scientists now know that chitosan can act as an exogenous inducer to trigger the activities of several defense-related enzymes in papaya fruit.? Over the past few years, numerous studies have demonstrated its effectiveness when used on its own or in combination with other natural compounds to preserve the physical properties of a variety of fruits and vegetables.? Because this biopolymer reduces the volatility of essential oils and masks the poor taste of essential oils, the incorporation of various essential oils into polymer matrices has attracted widespread attention. Many commercial chitosan formulations are available on the market for biopesticidal use. Other edible coatings Shellac, carboxymethyl cellulose, hydroxypropyl methylcellulose, bee wax and glycerol may have different applications and activities (fungicide, antioxidant and additive). Incorporating different components to create edible materials with appropriate functionality to meet a specific fruit or vegetable requirement is the focus of most studies. For example, some of these studies found that: Certain edible coatings, such as hydroxypropyl methylcellulose, have no antimicrobial activity but are used to enhance the antimicrobial activity of incorporated essential oils. This is how incorporating essential oil with aloe vera showed greater inhibition of Colletotrichum musae on bananas than aloe vera alone. Infections by decay-causing fungi were inhibited by 20?100% when the edible coating was applied to fruits and vegetables. In this way, grapefruit decay and chilling injury were reduced by combining shellac with carvacrol or thymol. The combination of carboxymethyl cellulose and stearic acid with phenylalanine reduced the incidence and severity of decay and improved the flavor of avocado fruit. Exopolysaccharide containing Lactiplantibacillus plantarum inhibited the growth of Fusarium spp. and Rhizopus stolonifer on cherry tomatoes. In short, the combination of various edible coatings with compounds that have antifungal properties has emerged as an alternative technology for post-harvest protection of fresh produce from pathogenic fungi. Exploring the potential of edible?coatings? The use of edible coatings has the potential to revolutionize the way to store and transport fresh produce in the future. Besides helping to extend the shelf life of fresh produce, edible coatings can reduce food waste, improve transportation, and offers health benefits. Reduce food waste Edible coatings can help reduce food waste by extending the shelf life of fresh produce. Since food waste is a major contributor to greenhouse gas emissions and represents a significant loss of resources, this can have significant environmental and economic benefits. Improve transportation Fresh produce can also be transported long distances without damage thanks to edible coatings. It helps protect fruits and vegetables from physical damage, temperature and humidity variations that affect quality and freshness. Offers health benefits Bioactive compounds such as antioxidants and antimicrobials can be incorporated into fresh produce using edible coatings. This can benefit consumer health as well as help prevent harmful microorganisms from growing. The Takeaway Several countries are increasingly restricting synthetic crop protection products, and export markets are demanding fruits and vegetables with no or low residues. According to the aforementioned study by the Italian university, research continues to explore the role of all-natural finishes as an environmentally friendly alternative that is biodegradable, consumable with packaged food, and derived from renewable resources. These coatings have shown promising results in extending shelf life, maintaining quality through the reduced gas exchange, slowing ripeness and inducing host defense mechanisms. Edible coatings could complement or replace traditional preservation methods. Unfortunately, most studies have been conducted at the laboratory scale and only a limited number of coatings are commercially available. To ensure market and consumer acceptance of coated fresh fruits and vegetables, further studies under semi-commercial and commercial conditions are needed to validate the efficacy of small-scale trials. Author:?Jorge Luis?Alonso G. (with ChatGPT)?Maximizing Agribusiness Profits with Expert Postharvest Storage Strategies | Horticultural Writing Specialist. This article was written exclusively for the business platform Postharvest. Cover photo:?Courtesy of Pixabay ?