Enhancing quality attributes of fresh-cut potatoes with gellan gum coatings added with “Rossa di Tropea” onion waste extract

Abstract

The aim of this work was to study the effect of an edible gellan gum–based coating with “Rossa di Tropea” onion waste extract onthe quality attributes and storage stability of fresh-cut potatoes. Color; texture; enzymatic activity (polyphenol oxidase, peroxidase,and pectin methylesterase); and antioxidant properties of fresh-cut potatoes were studied during 14 days of storage at 4°C.Changes in cellular structure, starch granule distribution, and extracellular spaces were also evaluated under a transmissionlight microscope on the day of production and on the last day of storage. The use of the coating enriched with “Rossa diTropea” onion waste extract preserved the main quality attributes of potatoes over time, thanks to the effective transport ofbioactive compounds such as those contained in the solid waste. Fresh-cut potatoes treated with gellan gum–based coatingsupplemented with onion waste extract preserved their physiological parameters, showing limited changes in color ΔE < 3, p <0 01 and, in combination with ascorbic acid (AA), a controlled browning development without significant changes over time,resulting in a better color preservation. In addition, GC + AA + OE fresh-cut potatoes were characterized by the highestcontent in TPC (413 9 ± 10 1 mg GAE kg−1) and a correlated higher antioxidant activity for both DPPH and ABTS assays(1117 2 ± 20 7 and 3242 1 ± 223 3 μM Trolox kg−1 , respectively) throughout storage. This treatment also resulted in a greatercontrol of PPO and POD activities, showing the lowest values from the first to the last day of storage (1.29–4.20 and 0.73–2.44UA g−1, respectively). The synergistic action between onion waste extract and the gellan gum–based coating was alsoconfirmed by the slight increase observed for PME activity (55.19–67.85 μmol s−1 g−1) and the quite constant texture values offresh-cut potatoes throughout storage, with over 41.6 N s−1 of cutting resistance on the 14th day.