foods Article Impact of Preharvest and Postharvest on Color Changes during Convective Drying of Mangoes Alioune Diop 1,2,3,4, * , Jean-Michel Méot 3,4 , Mathieu Léchaudel 4,5 , Frédéric Chiroleu 4,6 , Nafissatou Diop Ndiaye 2 , Christian Mertz 2,3,4 , Mady Cissé 7 and Marc Chillet 1,4   Citation: Diop, A.; Méot, J.-M.; Léchaudel, M.; Chiroleu, F.; Ndiaye, N.D.; Mertz, C.; Cissé, M.; Chillet, M. Impact of Preharvest and Postharvest on Color Changes during Convective Drying of Mangoes. Foods 2021, 10, 490. https://doi.org/10.3390/ foods10030490 Academic Editor: Min Zhang Received: 20 January 2021 Accepted: 22 February 2021 Published: 25 February 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 CIRAD, UMR QualiSud, 7, Chemin de l’IRAT, 97410 Saint-Pierre, La Réunion, France; marc.chillet@cirad.fr 2 ITA, Route des Pères Maristes, Hann-Dakar BP-2765, Senegal; ndiop@ita.sn (N.D.N.); christian.mertz@cirad.fr (C.M.) 3 CIRAD, UMR QualiSud, 34398 Montpellier, France; jean-michel.meot@cirad.fr 4 QualiSud, Univ Montpellier, CIRAD, Montpellier SupAgro, Univ d’Avignon, Univ de La Réunion, 34398 Montpellier, France; mathieu.lechaudel@cirad.fr (M.L.); frederic.chiroleu@cirad.fr (F.C.) 5 CIRAD, UMR QualiSud, 97130 Capesterre-Belle-Eau, Guadeloupe, France 6 CIRAD, UMR PVBMT, 7 Chemin de l’IRAT, 97410 Saint-Pierre, La Réunion, France 7 Laboratoire d’Electrochimie et des Procédés Membranaires (LEPM), ESP-UCAD, Dakar 10200, Senegal; mady.cisse@ucad.edu.sn * Correspondence: aliounediop23@gmail.com or alioune.diop@cirad.fr; Tel.: +22-177-2047-374 Abstract: The purpose of this study was to evaluate the impact of the harvest stage, ripening conditions and maturity on color changes of cv. ‘Cogshall’ and cv. ‘Kent’ variety mangoes during drying. A total of four harvests were undertaken, and the fruits were ripened at 20 and 35 ◦ C for five different ripening times at each temperature. At each ripening time, mangoes were dried at 60 ◦ C/30% RH/1.5 m/s for 5 h. A wide physico-chemical and color variability of fresh and dry pulp was created. The relationships according to the L*, H* and C* coordinates were established using mixed covariance regression models in relation to the above pre- and postharvest (preprocess) parameters. According to the L* coordinate results, browning during drying was not affected by the preprocess parameters. However, dried slices from mangoes ripened at 35 ◦ C exhibited better retention of the initial chroma, and had a greater decrease in hue than dried slices from mangoes ripened at 20 ◦ C. However, fresh mango color, successfully managed by the pre- and postharvest conditions, had more impact on dried mango color than the studied parameters. The preprocess parameters were effective levers for improving fresh mango color, and consequently dried mango color. Keywords: mango; maturity stage; ripening temperature; dried mangoes; color; quality 1. Introduction Drying represents one of the most common unit operations in the agri-food industry, for product stabilization. It greatly reduces the weight of the products, lowers water activity and slows microbe growth, as well as chemical and bio-chemical reactions. Hence, long storage and transport can be provided at a lower energy cost. Drying also alters the physical chemistry of foods, by causing changes in the mechanical properties [1], aromatic properties [2,3], nutritional properties [4,5], and color properties [6–9]. Color is generally the top purchase criterion for fruit [10], and for dried mangoes [11] in particular. Natural dried mangoes, without any added sugar or sulfites, are regarded as more dietetic and having a stronger taste [11]. The absence of added antioxidants means that they are prone to browning during preparation, drying and storage. Browning causes a color change in the mango slices from yellow-orange to brown-black, and when over-developed leads to rejection by consumers. The main fruit browning reactions are both enzymatic and nonenzymatic [12]. Enzy- matic browning of mangoes is caused by oxidation of phenolic compounds by polyphenol- oxidases (PPOs) and peroxidases (PODs). This reaction triggers a succession of other Foods 2021, 10, 490. https://doi.org/10.3390/foods10030490 https://www.mdpi.com/journal/foods