Gelatin-based coating enriched with blueberry juice preserves the nutraceutical quality and reduces the microbial contamination of tomato fruit

Abstract

To preserve quality and extend the shelf life of tomato, a bioactive edible coating was prepared using gelatin wastes from pharmaceutical industry and lyophilised blueberry juice (BJ). The effectiveness of gelatin-coating (G) and G enriched with blueberry juice (GB) was tested, monitoring carotenoids, polyphenols and flavonoids content, the antioxidant activity and the antimicrobial efficiency of coating against the native microflora.

After 7 d of storage, coated fruit showed higher phenolic and flavonoids content and increased antioxidant activity, while carotenoids were unaffected by the treatments. The growth of mesophilic bacteria of GB, and the growth of coliform bacteria of G and GB were significantly reduced during the entire period. The results indicate that GB preserved the nutritional quality of tomatoes and that BJ was able to increase the antimicrobial activity of the coating. This paves the way for a possible use of this biodegradable waste polymer as an eco-friendly coating material.

Keywords:

• Edible coatings
• carotenoids
• phenolic compounds
• fruit storage
• microbial contamination

Acknowledgements

Research supported by University of Pisa, Italy and by CNR, Consiglio Nazionale delle Ricerche, Italy. We thank Prof. Alessandro de Oliveira Rios and Dr. Carlos H. Pagno (Departamento de Ciência dos Alimentos, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brasil) for providing the gelatin used in this research.