Dakgalbi, a spicy stir-fried chicken dish that originated in Chuncheon, occupies a special place in Korean cuisine. A consumer survey cited by the authors found that Chuncheon dakgalbi accounted for 14.2 percent of preferred Korean-style chicken dishes for dining out. Beyond restaurants, the dish has strong potential in the home meal replacement sector, particularly in ready-to-cook formats that consumers can finish at home with minimal effort. The global home meal replacement market was valued at 564.5 billion US dollars in 2022 and is projected to reach 839.7 billion dollars by 2028, while the ready-to-cook segment is expected to grow at a compound annual rate of 6.83 percent between 2019 and 2025. Yet dakgalbi suffers from a persistent commercial weakness: a short shelf life driven by high initial microbial loads from raw chicken, vegetables, and sauce ingredients.

The research team tackled this problem using breast meat from Woorimatdag No. 1, a three-way crossbreed developed to overcome the slow growth and unstable supply of conventional Korean native chickens while retaining their distinctive flavor. The meat was diced, marinated in a soy sauce-based sauce at a one-to-four sauce-to-meat ratio, and divided into three treatments: an untreated control, and formulations containing either 0.14 percent or 0.18 percent pomegranate peel extract. The extract was prepared by washing and surface-sterilizing fresh pomegranates, separating the peels, grinding and freeze-drying them, and performing an aqueous extraction at a one-to-fifty weight-to-volume ratio for four hours at 20 degrees Celsius before a second lyophilization step yielded a dry powder.

Chemical analysis confirmed why pomegranate peel is such a promising candidate. The water-soluble extract contained 179.16 milligrams of gallic acid equivalents per gram of dry matter, a total phenolic content consistent with values reported in earlier literature. Pomegranate peel is particularly rich in hydrolyzable tannins, especially punicalagin and punicalin, along with ellagic acid and gallic acid, compounds recognized as the principal bioactive constituents of the peel. Antioxidant capacity, measured by three complementary assays, reached 2735.67 micromoles of Trolox equivalents per gram in the ABTS radical-scavenging test, 2285.85 micromoles per gram in the ferric reducing antioxidant power assay, and 1063.82 micromoles per gram in the oxygen radical absorbance capacity test. These phenolics are highly redox-active and can inhibit oxidative chain reactions in meat systems through radical scavenging, reducing power, and metal chelation.

The extract also displayed potent antimicrobial activity. In a paper disc diffusion assay against four major foodborne pathogens, pomegranate peel extract at concentrations ranging from 1.25 to 10 milligrams per disc generated measurable inhibition zones against all tested strains, with effects increasing dose-dependently. Salmonella Enteritidis proved the most sensitive organism, while Listeria monocytogenes was relatively less susceptible, a difference the authors attribute to species-specific variations in cell envelope structure, permeability, and stress adaptation. Even at the lowest dose of 1.25 milligrams per disc, inhibition zones exceeded 10 millimeters. The antimicrobial action is believed to involve disruption of the bacterial cell envelope, interference with membrane-associated proteins and enzymes, restriction of essential metal ions, and inhibition of biofilm formation.

When the fortified dakgalbi was vacuum-packaged and stored at 4 degrees Celsius for 16 days, the microbial results told a clear story. Total aerobic bacterial counts rose significantly in all treatments, but from day 12 onward the control group showed markedly higher counts than either extract-treated group. By day 16, counts stood at 6.27 log colony-forming units per gram in the control compared with 5.96 and 5.89 in the 0.14 percent and 0.18 percent treatments respectively, all remaining below the Korean Ministry of Food and Drug Safety limit of 6.70 log CFU per gram, although the control was approaching the threshold. Coliform counts told a similar tale, rising sharply by day 16 with significantly greater levels in the control than in the extract-treated samples. No Escherichia coli was detected in any treatment throughout storage.

Chemical spoilage indicators reinforced the microbiological picture. Total volatile basic nitrogen, a marker of protein degradation by microbial and endogenous enzymes, increased in all groups but was significantly lower in the treated samples by the end of storage, reaching 32.22 milligrams percent in the control compared with 27.46 and 28.66 milligrams percent in the two extract groups. Because soy sauce itself elevates baseline nitrogenous compounds, the authors caution that absolute values should be interpreted alongside the formulation and other spoilage indicators. Lipid oxidation, measured by thiobarbituric acid reactive substances, rose with storage time but did not differ significantly among treatments, indicating that under these conditions the extract did not effectively retard rancidity in the soy sauce-marinated breast meat product. Water-holding capacity, however, was better preserved: by day 16, the treated samples retained more moisture than the control, whose value had fallen to 46.10 percent, with the highest retention of 51.46 percent observed in the 0.14 percent group, a finding the authors link to better preservation of muscle protein functionality.

Sensory evaluation by a trained 15-member panel added an important consumer dimension. Appearance scores for the extract-containing samples declined after day 8, reflecting the darker color and reduced lightness and yellowness imparted by the dried peel powder. Flavor and off-flavor scores in the control deteriorated significantly by day 12, whereas the treated groups maintained these attributes without significant change, and overall acceptability was sustained through day 12 in all formulations. Notably, the proximate composition of the final products, containing roughly 20.20 to 20.73 percent crude protein and only 0.83 to 0.91 percent crude fat, was unaffected by extract supplementation, confirming that the addition improved functional quality without altering basic nutritional value. The authors concluded that the lower 0.14 percent addition level appeared sufficient, making it a practical choice for manufacturers seeking to balance efficacy against color penalties.

The study carries broader significance for the food industry’s search for natural alternatives to synthetic preservatives. Concerns over synthetic antioxidants have intensified demand for plant-derived solutions, and pomegranate peel, a waste stream of juice processing, has previously outperformed butylated hydroxytoluene in chicken patties and ascorbic acid in refrigerated sausages, and has shown potential as a nitrite substitute in dry-fermented products. Its application to Korean marinated chicken dishes, however, had remained largely unexplored. By demonstrating that the extract preserved the quality of dakgalbi primarily through suppressing microbial proliferation and proteolysis, and by validating Woorimatdag No. 1 breast meat as a suitable raw material, the researchers have opened a path toward longer-lasting, clean-label ready-to-cook chicken products. The authors note that further work is warranted to characterize shifts in the microbial community, standardize active compound levels, and confirm performance across wider processing conditions, but the message for an industry racing to meet demand for convenient, minimally preserved foods is clear: the answer may lie in the peel.

Subject of Research: Use of pomegranate peel extract as a natural preservative to improve the quality and refrigerated storage stability of marinated chicken dakgalbi

Article Title: Effect of pomegranate (Punica granatum L.) peel extract on the quality and storage stability of dakgalbi prepared from the breast meat of Korean native chicken

Article References: Jeong, D., Sujiwo, J., Jung, Y., Kim, D., Lee, H.-J., Oh, S., Lee, S., Choo, H.-J., & Jang, A. (2026). Effect of pomegranate (Punica granatum L.) peel extract on the quality and storage stability of dakgalbi prepared from the breast meat of Korean native chicken. Food Science of Animal Resources, 46(1), Article 95. https://doi.org/10.1007/s44463-026-00080-x

Image Credits: AI Generated

DOI: 10.1007/s44463-026-00080-x

Keywords: pomegranate peel extract, dakgalbi, Korean native chicken, Woorimatdag, natural preservatives, antimicrobial activity, antioxidant capacity, shelf life, meat quality, food storage stability, ready-to-cook meals, phenolic compounds

The researchers conducted extensive laboratory tests to assess the effectiveness of this biofilm on strawberries stored in refrigerated conditions. Remarkably, the fruit coated with this innovative film exhibited only an 11% weight loss over a span of 12 days. In contrast, uncoated strawberries began showing signs of fungal contamination after merely four days. This significant disparity highlights the film’s potential not only for extending the fruits’ freshness but also for serving as a protective barrier against spoilage and waste.

The collaborative effort received substantial backing from the São Paulo Research Foundation (FAPESP) and partnered with experts from EMBRAPA Instrumentation as well as the Federal University of São Carlos (UFSCar). Their findings were featured in a prestigious publication in the journal Food Chemistry, marking a significant milestone in food preservation research. The innovative biofilm showcases the team’s ability to harness local resources, turning what was once considered waste into a valuable asset for food preservation.

Central to the creation of this edible film is the extraction of antioxidants from pomegranate peel, a byproduct often discarded in food processing. Utilizing natural deep eutectic solvents (NADES), researchers achieved an impressive 84.2% increase in antioxidant extraction efficiency from pomegranate peels. This extraction mechanism significantly contributes to enhancing the shelf life of strawberries by infusing the biofilm with preservative properties that combat microbial growth and oxidative degradation.

The approach of utilizing pomegranate peels aligns with sustainable practices by repurposing agricultural waste into functional materials. As over 40% of a pomegranate can consist of peel, this research embraces an eco-friendlier methodology by reducing waste while simultaneously providing health benefits to consumers. The antioxidants derived from these peels not only enhance the biofilm’s functionality but also underscore the importance of exploring alternative applications for food industry byproducts.

To maximize the effectiveness of the biofilm, the research team chose to incorporate chitosan, a natural biopolymer extracted from the shells of crustaceans. Unlike chitosan derived from shrimp, which poses allergenic concerns, chitosan sourced from squid offers a safe alternative with similar beneficial properties. By combining chitosan and gelatin, the team created a robust film that could withstand different environmental conditions while ensuring the integrity of the strawberries during storage and transport.

Strawberries served as an ideal candidate for this study due to their high perishability and susceptibility to microbial attacks. Their relatively short shelf life of under a week and their high respiratory activity created a compelling case for testing this biofilm’s efficacy. Encouraged by preliminary results, researchers hypothesized that this protective film could potentially be effective on other fruits, leading to broader applications in the field of food preservation.

In testing the hypothesis, strawberries were coated through an immersion method, followed by evaluations of their physicochemical properties, microbiological safety, and sensory characteristics throughout the storage period. The treated strawberries displayed a remarkable ability to retain their texture, color, and bioactive compounds, demonstrating that the coating effectively slowed metabolic processes during the post-harvest phase. This innovative solution addresses not only the logistical challenges of fruit distribution but also the nutritional quality concerns prevalent in the industry.

The research team’s analysis showed that the edible film can successfully form a moisture-retentive barrier, preserving the fruit’s sensory qualities and preventing dehydration. Coated strawberries displayed significant improvements in maintaining weight and delaying fungal infections, ultimately contributing to enhanced market viability. Furthermore, the film’s ability to maintain the volatile compounds responsible for the fruit’s aroma highlights its positive influence on consumer preferences, supporting sensory appeal.

Remarkably, this biofilm does not alter the taste, aroma, or visual attributes of strawberries, as indicated during sensory analyses conducted with participants from the University. This further solidifies its potential application in commercial settings, where maintaining the original integrity of the fruit is crucial for customer satisfaction. As market readiness approaches, the team has filed a patent application for their formulation, ensuring that their research findings can be translated into practical solutions for industry stakeholders.

An estimated cost of BRL 0.15 per fruit has been projected for the application of this biofilm, suggesting that consumers may find the added expense reasonable for fruits with extended shelf life and enhanced usability. As food waste continues to present a growing concern worldwide, this innovation offers a progressive step towards tackling perishability issues while promoting sustainability within the agricultural domain.

In conclusion, the development of this edible biofilm signifies a pivotal breakthrough in food preservation technology. By leveraging waste materials and innovative techniques, researchers have paved the way for a more sustainable approach to maintaining the quality of perishable produce. As practical applications of their research emerge and the technology becomes available to interested companies, the potential impact on the agricultural industry and consumer habits could be profound.

Subject of Research: Edible biofilm for extending strawberry shelf life
Article Title: Improvement of the physical-chemical, microbiological, volatiles and sensory quality of strawberries covered with chitosan/gelatin/pomegranate peel extract-based coatings
News Publication Date: 2-Jan-2025
Web References: https://www.sciencedirect.com/science/article/abs/pii/S0308814625000056
References: Online journal publication in Food Chemistry
Image Credits: Mirella Romanelli Vicente Bertolo

Keywords

Food preservation, Edible biofilm, Strawberries, Antioxidants, Chitosan, Pomegranate, Sustainable agriculture, Food chemistry, Waste reduction, Microbial contamination, Shelf life extension, Agricultural research.