Antimicrobial, sealable and biodegradable packaging to maintain the quality of shredded carrots and pineapple juice during storage

Abstract

Increasing consumer demand for foods with high nutritional quality, prolonged shelf life and low environmental impact of the package, is driving innovation towards the development of new packaging. Multifunctional food packaging films, biodegradable, heat-sealable and antimicrobial, were developed. A PLA coating layer incorporating either sodium benzoate, potassium sorbate, or a combination of them was deposited onto a poly(lactic) acid/poly(butylene adipate-co-terephthalate) substrate film. The effectiveness of the developed systems to preserve the quality of foods was tested in shelf-life experiments performed on shredded carrots and pineapple juice, selected as model processed raw foods. The best performance was observed for the active film containing potassium sorbate: microbial populations increased less rapidly and were 0.7-1.8 log CFU/g lower at the end of storage period in this film than in control packs. Of the two model foods, the pineapple juice was better preserved: after 7 days in active packaging, color change and microbial counts of juice were below that of control, observed after one day and after 3 days of storage respectively. Moreover, the incorporation of the active phases did not significantly affect the mechanical, barrier and optical properties of the films, opening new ways to prolong shelf-life of minimally processed foods.

Supplementary information: The online version contains supplementary material available at 10.1007/s13197-022-05435-y.

Keywords: Active packaging; Biodegradable films; Carrot; Heat-sealability; Pineapple; Preservative; Shelf-life.

Fig. 1

Visual appearance of shredded carrots packed into the films containing antimicrobials after 7 days of storage. Arrows indicate black or white spots on the carrot surface. Film names: Control, no active phase; 15SB, sodium benzoate at 15 wt% in the coating layer; 15PS, potassium sorbate at 15 wt% in the coating layer; 15PS+SB, sodium benzoate and potassium sorbate in a 50/50 mass ratio at 15 wt% in the coating layer

Fig. 2

Total aerobic plate counts of shredded carrots (a), yeast and mold counts of shredded carrots (b), enterobacterium counts of pineapple juice (c) and yeast and mold counts of pineapple juice (d), packed in the control film (white bars), in 15SB (grey bars), in 15PS (black bars), in 15SB + 15PS (spotted bars) during refrigerated storage. Film names: Control, no active phase; 15SB, sodium benzoate at 15 wt% in the coating layer; 15PS, potassium sorbate at 15 wt% in the coating layer; 15SB + 15PS, sodium benzoate and potassium sorbate in a 50/50 mass ratio at 15 wt% in the coating layer. Means and standard errors are indicated. Same letter in a graph indicates no significant difference at p < 0.05