Effect of PLA Active Packaging Containing Monoterpene-Cyclodextrin Complexes on Berries Preservation

Abstract

Blackberries and raspberries are highly perishable and fragile products, which limits their shelf life. The effect of biodegradable active packaging of blackberries and raspberries containing 2.5% and 5.0% weight (wt%) of thymol or carvacrol complexed in β-cyclodextrins (β-CDs), successively added to poly (lactic acid) (PLA), and melt-processed by injection molding was evaluated under stored conditions at 4 °C for 21 days, using as reference commercial clamshell and PLA package control samples. Thus, physicochemical, headspace, microbiological, and sensory quality studies were carried out in order to compare the efficacy of the different packages. Concerning weight loss, color, and total phenolic and soluble solids content, significant differences were detected when compared with commercial clamshell packaging. The results show that the PLA packages containing thymol and carvacrol complexes maintained the color, weight, and phenolic content of berries until day 21, with a score up to 45% better compared to commercial clamshell. The headspace analysis detected 101 mg L−1 (ppm) of thymol and 35 ppm of carvacrol on the first day of refrigeration; these concentrations decreased with time. This release mechanism of carvacrol and thymol into the PLA package modified the initial atmosphere composition. After 21 days of storage, the berries had 4.25 degrees of acceptance, without adverse perception of aroma or flavor for both carvacrol and thymol compounds. A general microbial inhibition was observed for yeast and molds, which increased with the concentration of monoterpene in PLA packages, and showed an inhibition of 3.5 log units for PLA packages containing thymol, and of 3 log units for those containing carvacrol. Overall results show that PLA/β-CD-thymol 5.0% packages prolonged raspberries’ and blackberries’ shelf life by one more week at 4 °C, compared with commercial clamshell packaging.

The Effect of Controlled-Release Carvacrol on Safety and Quality of Blueberries Stored in Perforated Packaging

“…Cherry tomatoes coated with the combinations of chitosan and carvacrol exhibited weight loss between 11.1% and 14.2% at the end of storage, and higher carvacrol concentrations corresponded to lower weight loss [ 29 ]. Carvacrol complexed in β-cyclodextrins and poly(lactic acid) maintained the weight of blackberries and raspberries up to 21 days [ 35 ]. The result of the current research suggests a similar consequence of carvacrol treatment causing a retention of fruit firmness and reduction in weight loss.…”

Active PLA Packaging Films: Effect of Processing and the Addition of Natural Antimicrobials and Antioxidants on Physical Properties, Release Kinetics, and Compostability

“…This is due to the fact that most evidence related to the durability of PLA has been mainly associated to thermal decomposition, photo-oxidation, hydrolysis, thermo-oxidation at high temperatures, and natural weathering [ 1 , 87 ]. On the other hand, the monitoring of the functionality of active PLA films over time remains one topic to be considered by researchers for further industrial purposes [ 88 , 89 ].…”

Development of Bio-Composites with Enhanced Antioxidant Activity Based on Poly(lactic acid) with Thymol, Carvacrol, Limonene, or Cinnamaldehyde for Active Food Packaging

“…Moreover, the antioxidant activity of either thymol or carvacrol in PLA-based films was studied as a means to extend the shelf life of several foods, including salmon slices [42], lettuce [43,44], ground beef [45] and blackberries and raspberries [46].…”