The Effect of Drying Temperature on the Phenolic Content and Functional Behavior of Flours Obtained from Lemon Wastes

Jesús Patrón-Vázquez,Teresa Ayora-Talavera,Lizzie Baas-Dzul,Ángeles Sánchez-Contreras,Neith Pacheco,Nelly Medina-Torres,Ulises García-Cruz

doi:10.3390/agronomy9090474

Jesús Patrón-Vázquez, Teresa Ayora-Talavera + Show 5 more

Open Access

https://doi.org/10.3390/agronomy9090474

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Abstract

Lemon processing generates thousands of tons of residues that can be preserved as flours by thermal treatment to obtain phenolic compounds with beneficial bioactivities. In this study, the effect of different drying temperatures (40, 50, 60, 70, 80, 90, 100 and 110 °C) on the Total Phenolic Content (TPC), antioxidant and antimicrobial activities of phenolic compounds present in Citrus. lemon (L.) Burn f waste was determined. Identification and quantification of phenolic compounds were also performed by UPLC-PDA and UPLC-ESI-MS analysis. Eriocitrin (19.79–27.29 mg g−1 DW) and hesperidin (7.63–9.10 mg g−1 DW) were detected as the major phenolic compounds in the flours by UPLC-PDA and confirmed by UPLC-ESI-MS. Antimicrobial activity determined by Minimum Inhibitory Concentration (MIC) against Salmonella typhimurium, Escherichia coli and Staphylococcus aureus was observed. Accordingly, a stable functional flour as a source of bioactive phenolic compounds obtained from lemon residues at 50 °C may be produced as a value-added product useful in various industrial sectors.

Highlights

Mexico is one of the main producers of lemon, with a harvest estimated at 2.5 million tons in 2018 [1]
Lemon residues are rich in phenolic substances such as phenolic acids and flavonoids, which are responsible for a variety of helpful biological effects [7]
Antioxidant capacity has been reported for eriocitrin and hesperidin: two glycosylated flavanones found in these residues

Summary

Introduction

Mexico is one of the main producers of lemon, with a harvest estimated at 2.5 million tons in 2018 [1]. Industrial transformation generates thousands of tons of by-products with no commercial value, which are regularly discarded in adjacent areas, becoming an increasing problem of environmental pollution [3]. A part of the lemon by-products has been used for various purposes, including animal feed, fertilizer, charcoal, pectin source, and as a biofuel substrate [4,5,6]. The phytochemical compounds present in the lemon residues make it a potential source for food additives or supplements with high nutraceutical value. Lemon residues are rich in phenolic substances such as phenolic acids and flavonoids, which are responsible for a variety of helpful biological effects [7]. Antioxidant capacity has been reported for eriocitrin and hesperidin: two glycosylated flavanones found in these residues

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