Citral nanoemulsion incorporated edible coating to extend the shelf life of fresh cut pineapples

Citral is known as potent antibacterial agent, but its incorporation in food system is limited because of low water solubility and stability. Such limitations can be overcome by nano-emulsification of citral and its delivery on food surface through edible coating. In the present study, effect of sodium alginate based edible coating containing different concentrations of citral nanoemulsion i.e. 0.1% (NE1), 0.5% (NE2) and 1% (NE3) on the physicochemical, microbial and sensory quality of fresh cut pineapples stored at 4 degrees C and 90% relative humidity for 12 days were evaluated. The average droplet diameters of the nanoemulsion incorporated edible coatings were found to be in the nanometric range (66.67-131.08 nm). The interaction of nanoemulsion with the alginate was elucidated by FTIR. Among the treatments, NE2 and NE3 coated pineapple samples had better color retention (higher L* and b* values), lower respiration rate and reduced microbial growth during storage. NE2 coating application in pineapple also caused 2.52 and 2.23 log CFU/g reduction of artificially inoculated Salmonella enterica and Listeria monocytogenes. Incorporation of high citral concentration in NE3 led to the decrease in texture and sensory acceptance of the pineapple samples and therefore, NE2 could be further explored for commercial applications.