Extending Tomato Shelf Life with a Special Natural Coating

Jenn Hoskins
24th August, 2024

Extending Tomato Shelf Life with a Special Natural Coating

Image Source: Natural Science News, 2024

Key Findings

  • Researchers at GITAM University developed biodegradable films using CMC, pectin, PHB, and thymol for food packaging
  • Film F5, with 0.9% thymol, showed the best mechanical strength, antioxidant activity, and biodegraded in soil within 21 days
  • Film F5 significantly extended the shelf life of tomatoes by up to 15 days, preserving their firmness and delaying spoilage
The quest for sustainable alternatives to petroleum-based plastic films has gained significant momentum, driven by the urgent need to reduce environmental pollution. A recent study conducted by GITAM (Deemed to be University) explores the development of biodegradable polymeric films using carboxymethyl cellulose (CMC), pectin, polyhydroxybutyrate (PHB), and varying concentrations of thymol, with glycerol as a plasticizer[1]. This study aims to create films that not only possess desirable mechanical and optical properties but also exhibit strong antimicrobial and antioxidant activities, making them suitable for food packaging applications. The research team prepared films by solution casting technique, incorporating different concentrations of thymol (0.3%, 0.9%, 1.8%, 3%, and 5%) into a base matrix of CMC (4%), pectin (2%), and PHB (0.5%). The mechanical properties, such as tensile strength and Young's modulus, along with optical, antimicrobial, and antioxidant properties of the films, were thoroughly evaluated. Among the tested films, Film F5, which contained 0.9% thymol, showed the most promising results with a tensile strength of 15 MPa, Young's modulus of 395 MPa, and an impressive antioxidant activity (AA) of 92%. Additionally, Film F5 demonstrated rapid biodegradation in soil within 21 days and exhibited strong antimicrobial activity against various bacterial and fungal strains, including Klebsiella pneumoniae, Staphylococcus aureus, Escherichia coli, Aspergillus niger, and Aspergillus flavus. This study builds upon previous research that has investigated the incorporation of natural substances into CMC-based films to enhance their properties. For instance, the addition of summer savory essential oil (SSEO) to CMC-agar biocomposite films was shown to improve antimicrobial activity and mechanical flexibility while increasing water vapor permeability and reducing tensile strength[2]. Similarly, polysaccharides from chickpea hull (CHPS) were incorporated into CMC films, resulting in increased tensile strength, antioxidant effects, and improved thermal stability[3]. The current study extends these findings by demonstrating that the inclusion of thymol not only enhances the antimicrobial and antioxidant properties of CMC-based films but also maintains desirable mechanical properties at optimal concentrations. The study also highlights the impact of thymol concentration on the film's properties. Higher concentrations of thymol (1.8%, 3%, and 5%) led to a decrease in mechanical properties due to thymol's hydrophobic nature, which affects the film's structural integrity. This observation aligns with previous findings where the addition of certain natural compounds increased microstructural heterogeneity and affected mechanical properties[2]. To assess the practical application of the developed films, shelf life studies were conducted on tomatoes using three selected films: F2 (a film without thymol), F5 (the film with superior properties), and F7 (a film with low mechanical properties). The results indicated that Film F5 significantly enhanced the shelf life of tomatoes up to 15 days by preventing weight loss, preserving firmness, and delaying biochemical changes such as lycopene, phenols, and antioxidant activity. This demonstrates the film's potential for active food packaging and preservation, providing a sustainable solution to reduce food waste. In conclusion, the study conducted by GITAM (Deemed to be University) presents a viable alternative to petroleum-based plastic films through the development of biodegradable polymeric films incorporating CMC, pectin, PHB, and thymol. Film F5, in particular, stands out for its excellent mechanical, optical, antimicrobial, and antioxidant properties, making it suitable for extending the shelf life of fruits and vegetables. This research not only advances the field of biodegradable packaging materials but also offers practical applications for the food industry, contributing to environmental sustainability and food preservation.

VegetablesAgricultureBiochem

References

Main Study

1) Extension of shelf life of tomato (Solanum lycopersicum L.) by using a coating of polyhydroxybutyrate-carboxymethyl cellulose-pectin-thymol conjugate.

Published 22nd August, 2024

https://doi.org/10.1111/1750-3841.17312

Related Studies

2) Carboxymethyl cellulose-agar biocomposite film activated with summer savory essential oil as an antimicrobial agent.

https://doi.org/10.1016/j.ijbiomac.2018.12.115

3) Production and characterization of CMC-based antioxidant and antimicrobial films enriched with chickpea hull polysaccharides.

https://doi.org/10.1016/j.ijbiomac.2018.06.090


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