Combination of ferulic acid with Aloe vera gel or alginate coatings for shelf-life prolongation of fresh-cut apples

Abstract

Weight loss, microbial spoilage and enzymatic browning are the main quality-determining processes which limit the shelf-life of fresh-cut apples. In this study, two edible coatings based on Aloe vera gel (AV) and sodium alginate cross-linked with calcium lactate (AC), with the addition of 10 mg/mL ferulic acid (FA) as a functional ingredient, were developed in order to prolong the quality and safety of fresh-cut apple discs. Texture parameters, pH and Brix values and water activity did not undergo relevant changes related to the treatments. Except for weight loss, which was significantly lower for the coated samples, the addition of FA was found to be the most relevant factor for the other investigated parameters, including the total phenolic content and the antioxidant activity measured by ferric reducing antioxidant power (FRAP). Browning was delayed by the addition of FA and also by the AV coating, while non-coated and alginate coated samples showed the highest values in early stages. Although no effect on Saccharomyces cerevisiae was observed, FA treatments and alginate were effective in reducing Listeria monocytogenes populations by 2.3 ± 0.4 log CFU / g, which contributes to an enhanced product safety.

The Agrimax project received funding from the Bio-based Industries Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 720719. This work was also supported by the CERCA Programme of Generalitat de Catalunya. 720719. Nicolau-Lapeña is in receipt of a predoctoral grant awarded by the Spanish Ministry of Economy, Industry and Competitiveness (BES-2017-079779). Dr. I. Aguiló-Aguayo thanks the National Programme for the Promotion of Talent and Its Employability of the Spanish Ministry of Economy, Industry and Competitiveness, and the European Social Fund for her Postdoctoral Senior Grant ‘Ramon y Cajal’ (RYC-2016-2019 949).