Creating Edible Coatings from Apple Waste Using Natural Plant Fibers

Jim Crocker
27th August, 2024

Creating Edible Coatings from Apple Waste Using Natural Plant Fibers

Image Source: Natural Science News, 2024

Key Findings

  • Researchers at Shaanxi Normal University developed edible coatings from apple pomace to extend the shelf life of fresh-cut apple slices
  • The coatings are made by breaking down apple pomace fibers into nanofibers, which are then formed into films with strong mechanical and oxygen barrier properties
  • These coatings are non-toxic and effectively inhibit browning and reduce respiration rates, keeping apple slices fresh and firm for longer
Minimally processed fruits and vegetables (MPFVs) have become increasingly popular due to their convenience and fresh quality. However, the management of perishable waste pomaces (WPs) and the short shelf-life of these products remain significant challenges. A recent study by researchers at Shaanxi Normal University offers a promising solution by developing edible bio-nanocomposite coatings from apple pomace (AP) to extend the shelf life of fresh-cut apple slices[1]. The study addresses two main issues: the waste generated from fruit processing and the rapid spoilage of MPFVs. Apple pomace, a byproduct of apple juice production, is often discarded, contributing to environmental waste. By repurposing this waste into edible coatings, the researchers aim to reduce waste and enhance the preservation of fresh-cut fruits. The process begins with alkaline demethylation, a chemical reaction that modifies pectin, a natural polysaccharide found in the cell walls of plants. This step releases carboxyl groups (-COO-) at a concentration of 1.23 mmol g-1, improving the fibrillation of AP fibers. Fibrillation refers to the breaking down of fibers into smaller, more manageable pieces. The demethylated AP fibers are then subjected to high-pressure homogenization, which further reduces their size to an average width of 18 nm, creating apple pomace nanofibers (AP-NFs). The AP-NFs are then cast into films, forming a homogeneous coating with desirable properties. These films exhibit a transparency of 56% at 600 nm, making them visually appealing for use on food products. They also demonstrate superior mechanical strength, with a Young modulus of 6.4 GPa and a tensile strength of 81.7 MPa. Additionally, the films have excellent oxygen barrier properties, measured at 79 mL μm m-2 day-1 bar-1, which is crucial for slowing down the oxidation process that leads to spoilage. One of the significant findings of this study is the non-toxicity of the AP-NF coatings, making them safe for use on food products. When applied to fresh-cut apple slices, these coatings effectively inhibit browning and reduce respiration rates, which are key factors in extending shelf life. The coated apple slices retain their firmness and freshness for a longer period compared to untreated slices. This innovative approach not only addresses the issue of food waste but also offers a sustainable method to enhance the quality and longevity of MPFVs. The findings build on previous research that explored various methods to preserve MPFVs. For instance, the use of chlorine for disinfection has been widely adopted due to its low cost and high efficacy. However, it poses health risks due to the formation of suspected carcinogenic compounds in high organic wash water[2]. The new method using AP-NFs provides a safer alternative without compromising the quality of the produce. Additionally, the study aligns with recent advancements in the use of biopolymer-based edible films containing probiotics to preserve MPFVs. These films offer barrier, antioxidant, and antimicrobial functions while maintaining the nutritional value and quality of the produce[3]. The AP-NF coatings developed in this study could potentially be combined with probiotic-loaded films to further enhance their preservative effects. Moreover, the research draws parallels with other studies that have utilized fruit processing byproducts for creating functional materials. For example, biopolymer films developed from apple peels have shown promising physical properties such as water vapor permeability and oxygen permeability, which are essential for food packaging[4]. The AP-NF coatings developed in this study exhibit similar barrier properties, making them suitable for extending the shelf life of fresh-cut fruits. Overall, this study by Shaanxi Normal University demonstrates a practical and sustainable approach to valorize fruit processing waste and improve the shelf life of MPFVs. By converting apple pomace into effective edible coatings, the research provides a viable solution to the challenges of food waste management and product preservation in the modern food industry.

SustainabilityBiotechPlant Science

References

Main Study

1) Fabraction of edible bio-nanocomposite coatings from pectin-containing lignocellulosic nanofibers isolated from apple pomace.

Published 24th August, 2024

https://doi.org/10.1016/j.ijbiomac.2024.135030

Related Studies

2) Improving the shelf-life and quality of fresh and minimally-processed fruits and vegetables for a modern food industry: A comprehensive critical review from the traditional technologies into the most promising advancements.

https://doi.org/10.1080/10408398.2018.1553025

3) Probiotic-loaded edible films made from proteins, polysaccharides, and prebiotics as a quality factor for minimally processed fruits and vegetables: A review.

https://doi.org/10.1016/j.ijbiomac.2023.127226

4) Apple peel-based edible film development using a high-pressure homogenization.

https://doi.org/10.1111/j.1750-3841.2009.01273.x


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