Stronger, Water-Resistant Food Wrap for Longer-Lasting Cherry Tomatoes

Jenn Hoskins
26th July, 2024

Stronger, Water-Resistant Food Wrap for Longer-Lasting Cherry Tomatoes

Atomic force microscopy images reveal that zein aggregates are uniformly distributed within the entangled molecular network formed by Konjac glucomannan and curdlan, demonstrating the good compatibility of the components in the composite system.

Image adapted from: Tian et al. / CC BY (Source)

Key Findings

  • Researchers at Hubei University of Technology developed a new packaging material by adding zein to a konjac glucomannan/curdlan system
  • The optimized zein content in the packaging film improved water resistance, tensile strength, and elongation at break
  • The new packaging significantly reduced water loss and maintained the quality of cherry tomatoes during storage
The preservation of fruits and vegetables during storage is a significant concern due to the potential for moisture loss, microbial contamination, and degradation of nutritional quality. Addressing these issues effectively can extend shelf life and maintain the quality of produce. Recent research conducted by Hubei University of Technology has focused on improving the mechanical and barrier properties of packaging materials to enhance the preservation of fruits and vegetables, particularly cherry tomatoes[1]. The study introduced zein, a hydrophobic substance, into a konjac glucomannan (KGM)/curdlan (KC) system to form a new packaging material. Zein is a type of protein found in corn that is known for its water-resistant properties. By incorporating zein into the KGM/curdlan matrix, the researchers aimed to create a packaging film that could better protect fruits and vegetables from moisture loss and maintain their quality during storage. The KC/zein (KCZ) films demonstrated good compatibility, with zein aggregates uniformly distributed within the network formed by the entanglement of KGM and curdlan micelles. This network is held together by hydrogen bonds, which are a type of chemical bond that occurs when a hydrogen atom is attracted to a highly electronegative atom. The addition of zein inhibited the extension of the KC entangled structure, enhancing the solid-like behavior of the films. One of the key findings of the study was that a high content of zein (greater than 6%) led to excessive zein aggregation, which negatively affected the structure and properties of the KCZ films. However, when the zein content was optimized, the films showed significant improvements in water vapor permeability, tensile strength, and elongation at break. These properties are crucial for creating a durable and effective packaging material. The hydrophobicity of the KCZ films was significantly enhanced, as evidenced by an increase in the water contact angle from 81° to 112°. Hydrophobicity refers to the ability of a material to repel water. The increased water contact angle indicates that the KCZ films are more water-resistant, which is beneficial for preserving the moisture content of fruits and vegetables. Additionally, the moisture content, swelling, and soluble solid loss ratio of the films decreased, further indicating their improved water resistance. The study specifically highlighted the effectiveness of the K56C40Z4 coating in preserving cherry tomatoes. This coating significantly reduced water loss and the decline in firmness of the tomatoes. It also helped maintain the appearance, total solid content, total acid content, and ascorbic acid content of the tomatoes. Ascorbic acid, also known as vitamin C, is an important nutrient that can degrade over time, so maintaining its content is crucial for the nutritional quality of the tomatoes. These findings build upon earlier research that explored various methods for preserving fruits and vegetables. For instance, previous studies have shown that biopolymer films can inhibit moisture loss and improve preservation efficiency[2]. The current study enhances this understanding by demonstrating that the addition of zein to a biopolymer matrix can further improve the water resistance and mechanical properties of the packaging material. Additionally, the study aligns with research on the use of antimicrobial treatments to extend the shelf life of produce. For example, the combination of aqueous ozone and ultrasound has been shown to enhance microbial safety without compromising the nutritional quality of cherry tomatoes[3]. Similarly, the use of antifungal compounds like Bacillomycin D and chitosan has been effective in reducing postharvest fungal rot and maintaining storage quality[4]. The current study complements these approaches by providing a physical barrier that can protect against moisture loss and microbial contamination. In conclusion, the research conducted by Hubei University of Technology presents a promising strategy for enhancing the preservation of fruits and vegetables through the development of hydrophobic packaging materials. By incorporating zein into a KGM/curdlan matrix, the researchers have created a film that significantly improves water resistance and mechanical properties, thereby extending the shelf life and maintaining the quality of produce like cherry tomatoes. This work represents a valuable contribution to the field of food preservation and offers a practical solution for reducing food waste and ensuring the nutritional quality of stored produce.

AgricultureBiotechPlant Science

References

Main Study

1) Improvement of mechanical, barrier properties, and water resistance of konjac glucomannan/curdlan film by zein addition and the coating for cherry tomato preservation.

Published 23rd July, 2024

https://doi.org/10.1016/j.ijbiomac.2024.134132

Related Studies

2) Moisture loss inhibition with biopolymer films for preservation of fruits and vegetables: A review.

https://doi.org/10.1016/j.ijbiomac.2024.130337

3) Sonozonation: Enhancing the antimicrobial efficiency of aqueous ozone washing techniques on cherry tomato.

https://doi.org/10.1016/j.ultsonch.2020.105059

4) Effect of combined Bacillomycin D and chitosan on growth of Rhizopus stolonifer and Botrytis cinerea and cherry tomato preservation.

https://doi.org/10.1002/jsfa.10635


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