Usage of 405 nm LED light to extend the storage time and food safety level of strawberries in refrigerators

Date

2024-9

Author

Güven, Özge

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Strawberries (Fragaria × ananassa) are extensively consumed in their fresh form and are well known for their high content of natural antioxidants, including anthocyanins, flavonoids, and phenolic compounds. However, their delicate texture, high metabolic activity, and vulnerability to fungal attacks make them highly perishable. LED light at 405 nm, known for its antimicrobial properties, is now being applied to prevent microbial growth on fresh produce. This study uses strawberries as a model food to evaluate 405 nm LED light in refrigerators. Strawberries were placed in refrigerators with 405 nm LED lights providing low and high irradiation and a control refrigerator without light at 4.4±0.2℃. The application involved a 3 days light treatment followed by a 1 week storage period. The reduction of microbial load was studied using Escherichia coli ATCC 25922 and Botrytis cinerea. After treatment, 1.32±0.07 log CFU/g and 2.01±0.18 log CFU/g inhibition was observed for Escherichia coli; 0.86±0.08 log CFU/g and 0.97±0.08 log CFU/g inhibition were observed for Botrytis cinerea in low irradiance and high irradiance refrigerators, respectively. Physicochemical analyses showed that the 405 nm LED light application could preserve and even enhance the nutritional content during the storage period, as indicated by the total phenolic content, antioxidant activity, total anthocyanin content, and ascorbic acid content analyses (p<0.05). However, no significant improvement was observed compared to the control refrigerator regarding weight loss, color, total soluble solids, titratable acidity, texture, ethylene, oxygen and carbon dioxide levels, and Time Domain Nuclear Magnetic Resonance relaxometry measurements (p>0.05). Nonetheless, continuous low irradiance light was more effective in maintaining physicochemical properties, suggesting it is more energy efficient and sustainable than high irradiance light.

Subject Keywords

Strawberry, LED Light Technology, Food Preservation, Cold Storage, Shelf-lif

URI

https://hdl.handle.net/11511/111375

Collections

Graduate School of Natural and Applied Sciences, Thesis