Recent developments in nanoemulsions against spoilage in cold-stored fish: A review

Nanoemulsion-based technology is developing rapidly in the food industry, especially in the design of delivery systems for bioactive compounds. This review presents an in-depth understanding of the composition, function, antibacterial mechanism and successful application of nanoemulsions as preservative agents against fish spoilage. The results showed that the inclusion of bioactive substances in the food-grade nanoemulsions encapsulation system could improve its stability, control its release, inhibit the microbial growth and reproduction through a variety of targets. These nanoemulsions can inhibit fish spoilage via reducing microbial load and retarding the oxidation of proteins and lipids, thereby maintaining quality attributes of fish. In addition, nanoemulsions could be coupled with vacuum package for enhancing microbial destruction, retaining nutritional value and extending the shelf-life of fish. Accordingly, nanoemulsions are suggested as a promising strategy to inhibit fish spoilage.

Antibacterial effects of extracted corn zein with garlic extract-based nanoemulsion on the shelf life of Vannamei prawn (Litopenaeus vannamei) at refrigerated temperature

BACKGROUND

Litopenaeus vannamei is one of the most perishable foods due to microorganism growth. Using essential oil-based nanoemulsion as a biodegradable and edible coating can enhance the shelf life of shrimp at refrigerated temperature through retarding microbial growth compared to synthetic coatings.

METHODS

Zein was extracted from 50 g dry milled corn with ethanol. Garlic essential oil was prepared by mixing with Tween 80. Nanoemulsion was prepared in an ultrasonic bath. DLS analysis, turbidity, and stability of nanoemulsions were performed. Radical scavenging activity, and total phenol content were done for evaluation of garlic essential oil and nanoemulsion. A 10% zein solution was prepared using ethanol 95% and glycerol plasticizer (2.5%). In the end, various microbial analysis, peroxide value, the thiobarbituric acid reactive substance (TBARS) value, the total volatile basic nitrogen (TVB-N) values, and sensory evaluations of different shrimp samples were determined.

RESULTS

Corn zein along with garlic-based nanoemulsion, had a great impact on the TVB-N, TBARS, and peroxide value (which indicated that z+24% garlic nanoemulsion group was the lowest among other groups on days 3, 7, and 14 (p < 0.05) as well as microbial properties (garlic EO nanoemulsion had significantly better antibacterial effectiveness compared to other groups (p < 0.05)), and sensory evaluation (the z+24% garlic nanoemulsion sample received a significantly higher score than other groups (p < 0.05)) of Litopenaeus vannamei.

CONCLUSIONS

Corn zein nanoemulsion functioned as an antioxidant and antimicrobial agent, increasing the shelf life of Litopenaeus vannamei at refrigerated temperature.

PRACTICAL APPLICATION

Emerging nanotechnology-based approaches with no side-effects on immune system of consumers plays a vital role in bioactive packaging, and on reduction of food spoilage or food poisoning in the transportation, exporting, and distribution stages of food products, especially marine-based products with cold chain transportation. Additionally, it can reduce aquaculture and environmental risks due to the usage of chemical agents used in packaging. Our results showed that administration of a corn zein with nanoemulsion of garlic extract can prolong shelf life of Litopenaeus vannamei. The paper should be of interest to readers such as food microbiologists, aquaculture scientists, fisheries scientists, marine biologists, biomaterial scientists, food packaging industrialists, medical microbiologists, public health managers, and health system managers.