Edible Coating with Good Bacteria Keeps Strawberries Fresh Longer

Jenn Hoskins
22nd June, 2024

Edible Coating with Good Bacteria Keeps Strawberries Fresh Longer

Garden strawberry (Fragaria × ananassa)

Photo adapted from: Oleg Kosterin / CC BY (Source)

Key Findings

  • Researchers at Northwest A&F University found that sodium alginate-based coatings with lactic acid bacteria can effectively preserve strawberries
  • These coatings significantly reduced weight loss, decay, and ascorbic acid degradation in strawberries
  • Strawberries treated with these coatings had much lower fungal growth compared to untreated ones, enhancing their shelf life and safety
Edible coatings have emerged as a promising solution for extending the shelf life of perishable fruits and vegetables. A recent study conducted by researchers at Northwest A&F University evaluated the effectiveness of sodium alginate-based coatings, combined with various strains of lactic acid bacteria, in preserving strawberries and mitigating microbial risks associated with their storage[1]. Strawberries are known for their high vitamin C and phenolic compound levels, which contribute significantly to their antioxidant properties and overall health benefits[2]. However, they are also highly perishable, making effective preservation methods essential. Traditional methods such as refrigeration can delay ripening and reduce microbial growth but are insufficient once the fruits are exposed to ambient temperatures[3]. This new study builds on prior research by exploring the potential of alginate-based coatings to offer a more sustainable and health-conscious alternative to synthetic fungicides[4]. The study specifically investigated the use of three strains of lactic acid bacteria—Lacticaseibacillus paracasei, Lacticaseibacillus rhamnosus, and Lacticaseibacillus plantarum—as antimicrobial agents in the coatings. The findings revealed that these alginate-based antimicrobial coatings were highly effective in reducing the rate of weight loss, decay index, and ascorbic acid degradation in strawberries. Despite an overall increase in fungal growth over time, the strawberries treated with the alginate and lactic acid bacteria coatings exhibited significantly lower final colony formation counts compared to the control group. Specifically, the counts were 6.82 log CFU/g for SA + LPC, 6.04 log CFU/g for SA + LGG, and 6.26 log CFU/g for SA + LP, compared to 8.73 log CFU/g in the untreated control group. The study also highlighted the bacterial resistance of these lactic acid bacteria strains under gastrointestinal conditions. L. paracasei demonstrated the highest survival rate post-simulated gastric fluid exposure, while L. plantarum showed the greatest resilience post-simulated intestinal fluid exposure. This aspect of the study underscores the potential benefits of these coatings not only in enhancing the storage quality of strawberries but also in contributing to gut health. Edible coatings made from biopolymers like sodium alginate have been gaining attention due to their biodegradability and ability to extend the shelf life of various food products[3]. Alginates, derived from marine brown algae, possess excellent film-forming properties, low permeability to oxygen and vapors, and are flexible, water-soluble, tasteless, and odorless. When combined with additives such as organic acids, essential oils, and plant extracts, alginate coatings can enhance moisture retention, reduce shrinkage, retard oxidation, inhibit color and texture degradation, and reduce microbial load, thereby extending the shelf life of the coated products[4]. This study's findings are particularly relevant for Argentina, a major producer and exporter of strawberries, where the need for effective postharvest treatments is critical to maintaining fruit quality and safety during transport and storage[2]. The incorporation of antimicrobial agents like lactic acid bacteria into alginate coatings offers a natural and safer alternative to synthetic fungicides, aligning with global trends towards more sustainable and health-conscious food preservation methods[3][4]. In conclusion, the research conducted by Northwest A&F University demonstrates the efficacy of alginate-based antimicrobial coatings in preserving strawberries. By reducing weight loss, decay, and ascorbic acid degradation, and by providing antimicrobial protection, these coatings represent a significant advancement in postharvest technology. The study not only addresses the immediate need for better preservation methods for strawberries but also contributes to broader efforts in developing sustainable and health-promoting food packaging solutions.

FruitsHealthBiotech

References

Main Study

1) An alginate-based edible coating containing lactic acid Bacteria extends the shelf life of fresh strawberry (Fragaria × ananassa Duch.).

Published 19th June, 2024

https://doi.org/10.1016/j.ijbiomac.2024.133273

Related Studies

2) Bioactive Compounds and Antioxidant Capacity of Camarosa and Selva Strawberries (Fragaria x ananassa Duch.).

https://doi.org/10.3390/foods2020120

3) Recent advances in the use of edible coatings for preservation of avocados: A review.

https://doi.org/10.1111/1750-3841.15540

4) Use of Alginates as Food Packaging Materials.

https://doi.org/10.3390/foods9101440


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