Effects of Active Paper Sheets on the Quality of Cherry Tomatoes and Kale During Storage

The effect of active packaging on maintaining the quality of cherry tomatoes and kale during storage was investigated. The active packaging consisted of kraft paper sheets coated with thymol/eugenol (50:50) encapsulated in β-cyclodextrin. Cherry tomatoes were stored at 10, 15, and 22 °C for 15, 14, and 8 days, respectively, while kale was stored at 2, 8, 15, and 22 °C for 21, 16, 9, and 7 days. Physicochemical (pH, total soluble solids, titratable acidity, colour, and firmness), microbiological (mesophilic, psychrophilic, enterobacteria, moulds, and yeasts) and pigment/bioactive/nutritional (chlorophylls, carotenoids, total phenolic content, vitamin C, and total antioxidant capacity) characteristics were analysed. Active packaging significantly reduced microbial growth, particularly enterobacteria and moulds, in cherry tomatoes and psychrophiles and moulds in kale, without negatively affecting the physicochemical quality. The microbial kinetics were successfully described using the Baranyi-Ratkowsky predictive model, which quantified the effects of temperature and active packaging on microbial growth parameters. This modelling approach revealed that active packaging increased the minimum growth temperature and reduced the specific growth rate of key microbial groups, confirming its inhibitory action under different storage conditions. The use of active packaging slowed colour degradation in kale by reducing chlorophyll loss up to 50% at 22 °C and maintained tomato firmness and colour during storage. Furthermore, a strong correlation (R² = 0.87) between colour index and carotenoid content was found, enabling the non-destructive prediction of ripening in tomatoes. Overall, active packaging enhanced microbial stability, delayed visual deterioration, and sustainably extended the shelf life and post-harvest quality of perishable products, offering a promising alternative to conventional preservation methods.