Original Research Article Non-destructive determination of b-carotene content in mango by near-infrared spectroscopy compared with colorimetric measurements Parika Rungpichayapichet a , Busarakorn Mahayothee b, *, Pramote Khuwijitjaru b , Marcus Nagle a , Joachim Mu ¨ ller a a Universita ¨t Hohenheim (440e), Institute of Agricultural Engineering, Tropics and Subtropics Group, Stuttgart 70599, Germany b Silpakorn University, Faculty of Engineering and Industrial Technology, Department of Food Technology, Nakhon Pathom 73000, Thailand 1. Introduction Mango is a major global fruit crop that is widely grown in tropical and subtropical regions around the world. Increasing demand has stimulated production to rise about 17% from 2008 to 2012, with the major producers in terms of volume being India, China and Thailand, respectively (FAOSTAT, 2014). Mango is a good source of vitamins, minerals and other bioactive compounds (Liu et al., 2013; Ma et al., 2011; Masibo and He, 2009; Schieber et al., 2000). In mango, the colour of both the fruit peel and the fruit flesh is governed by concentrations of chlorophyll and carotenoid pigments. During ripening, colour of the flesh (and in some cultivars peel as well) shifts from green to yellow-orange, due to chlorophyll degradation in conjunction with carotenoid biosynthe- sis (Gouado et al., 2007; Va ´ squez-Caicedo et al., 2006). There are 17 major carotenoids found in mango, amongst them b-cryptoxanthin, zeaxanthin, luteoxanthin isomers, violaxanthin, neoxanthin and b- carotene, with the last being the most prevalent (Mercadante et al., 1997; Ornelas-Paz et al., 2007). Carotenoid content is affected by various factors, such as ripening stage, cultivar and processing method (Gouado et al., 2007; Mahayothee et al., 2007). Mercadante and Rodriguez-Amaya (1998) reported that total carotenoid content increased about threefold during ripening and other research stated that carotenoid accessibility was greater in ripe fruits than in unripe ones (Ornelas-Paz et al., 2008). Therefore, ripened mango is a good source of provitamin A and can be a nutritional source for malnourished people and also for customers who are interested in functional foods (West and Darnton-Hill, 2008). Journal of Food Composition and Analysis 38 (2015) 32–41 A R T I C L E I N F O Article history: Received 19 May 2014 Received in revised form 11 July 2014 Accepted 2 October 2014 Available online 18 November 2014 Chemical compounds studied in this article: b-Carotene Type II (PubChem CID: 5280489) Keywords: Mangifera indica Provitamin A HPLC Near-infrared spectroscopy Food analysis Food composition Wavelength selection Fruit colour b-Carotene Carotenoid Food pigment and nutrition A B S T R A C T Non-destructive applications for the detection of food quality, especially internal properties, are highly relevant for process control in the food industry. In this respect, colour measurement and near-infrared spectroscopy (NIRS) were evaluated and compared for their ability to predict b-carotene content in mango cv. ‘Nam Dokmai’. Colorimetric analysis of peel and flesh colour as well as NIR measurements in the short- (700–1100 nm) and long-wave regions (1000–2500 nm) were analysed for prediction ability. It was found that b-carotene content could be estimated by multiple linear regression (MLR) models developed from b* and hue angle (h8) values of the flesh with good results for coefficient of determination (R 2 ) and standard errors of cross validation (SECV) of 0.941 and 10.2 retinol equivalents (RE) 100 g 1 edible part (EP), respectively, while peel colour showed poor results. However, flesh colour measurement is a destructive method. NIRS calibration showed good results with R 2 > 0.800 and standard error of prediction (SEP) 11.642–20.2 RE 100 g 1 EP. Long-wave NIR provided better prediction ability than short-wave. From these results, NIRS can be recommended for non-destructive and reliable determination of b-carotene content in mango. The results have implications for quality control in the industrial handling and processing of fruits. ß 2014 Elsevier Inc. All rights reserved. * Corresponding author. Tel.: +49 0711 459 22480; fax: +49 0711 459 23298. E-mail address: busarakorn@su.ac.th (B. Mahayothee). Contents lists available at ScienceDirect Journal of Food Composition and Analysis jo u rn al ho m epag e: ww w.els evier .c om /lo cat e/jfc a http://dx.doi.org/10.1016/j.jfca.2014.10.013 0889-1575/ß 2014 Elsevier Inc. All rights reserved.