Quality of Physalis peruviana fruits coated with pectin and pectin reinforced with nanocellulose from P. peruviana calyces

Physalis peruviana is marketed without its calyx, which generates byproducts and a decrease in the shelf life of these fruits. The aim of this study was to evaluate the effect of edible pectin-coatings reinforced with nanocellulose from calyx on the physical-chemical and physiological parameters of P. peruviana fruits during refrigerated storage (5 °C) for ten days. The nanocellulose extraction was carried out using a combined extraction method (chemical procedures and ultrasound radiation). The characterization of the fibers showed that the maximum degradation temperatures ranged between 300 and 311 °C. The SEM analysis revealed the presence of fibers after the chemical treatment. The removal of lignin and hemicellulose was validated using Fourier Transform Infra Red (FTIR) spectroscopy. The results showed that the fruits treated with pectin and pectin reinforced with nanocellulose at 0.5 % (w/w) had an adequate visual appearance and showed a minor color change (ΔE of 19.04 and 21.04, respectively) and the highest retention of L∗ during storage. Although the addition of nanocellulose at 0.5% presented the lowest respiratory rate (29.60 mgCO(2)/kg h), the treatment with pectin offered the least weight loss and showed the highest firmness retention at the end of storage. Thus, the edible pectin-coating may be useful for improving the postharvest quality and storage life of fresh P. peruviana fruit. Nanocellulose from P. peruviana calyces can be used under the concept of a circular economy; although, its use as a reinforcement of pectin showed some limitations.