Industrial orange juice debittering: Impact on bioactive compounds and nutritional value Carla M. Stinco a , Rocío Fernández-Vázquez a , Dolores Hernanz b , Francisco J. Heredia a , Antonio J. Meléndez-Martínez a , Isabel M. Vicario a,⇑ a Food Colour & Quality Lab., Dept. Nutrition & Food Science, Universidad de Sevilla, Facultad de Farmacia, 41012 Sevilla, Spain b Dept. Analytical Chemistry, Universidad de Sevilla, Facultad de Farmacia, 41012 Sevilla, Spain article info Article history: Received 27 August 2012 Received in revised form 16 November 2012 Accepted 19 November 2012 Available online 29 November 2012 Keywords: Carotenoids Colour Debittering Orange juice Phenolics abstract The impact of an industrial debittering process (DP) on nutritional and bioactive compounds in orange juice (OJ) was studied. The DP was aimed at removing bitter components in OJ by physical adsorption in a resin. The levels of bioactive compounds (carotenoids, ascorbic acid and phenolics), total antioxidant activity and the colour in the fresh orange juices (non-debittered) and in the debittered counterparts were measured. The results demonstrated that the carotenoid contents were not significantly affected by the treatment. However, the debittered orange juices showed a reduction (p < 0.001) of 26% in ascorbic acid, 32% in hydroxycinnamic acids, 28% of flavones and 41% of flavanones in comparison with the non- treated juices. The antioxidant activity of the hydrophilic fraction (HF) was significantly higher (p < 0.05) in untreated juice than in debittered juices. Some colour parameters (L / , a / and h ab ) were also affected. Discriminant analysis revealed that the canonical function related to the levels of HF compounds allowed a 100% correct classifications of the different types of juices. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Taste is one of the sensory quality attributes that, together with colour and flavour determines food selection. Bitter or astringent tastes tend to be rejected by the consumer, for that reason early season orange juice (OJ) or OJ from immature fruits must be sub- jected to an appropriate treatment to reduce bitterness. Limonoids and flavonoids are the main groups of bitter com- pounds in citrus. Limonin, nomilin, and nomolinic acids are triter- pene derivates compounds that occur gradually in certain varieties of citrus after juice processing giving a ‘‘delayed bitterness’’ (Puri et al., 1996). Limonin is the most representative compound in this group (Kimball and Kimball, 1991). Among flavonoids some are bitter while others are not, depending on the type of chain glyco- sides. The neohesperidose flavanones (rhamnosyl-a-1,2 glucose) (Fig. 1), such as naringin, neohesperidin and neoeriocitrin are responsible for the bitter taste in grapefruit and bitter orange while rutinoside flavanones (rhamnosyl-a-1,6 glucose) such as hesperi- din, narirutin and didymin are tasteless (Horowitz, 1986). Naringin is found in the membranes and albedo of the fruit and is extracted into the juice, giving it an ‘immediate’ bitterness when their levels exceed 20 ppm (Fisher and Wheaton, 1976). The bitterness level can be reduced by different technologies based on chemical, physical or microbiological processes. The cur- rent industrial technology for debittering is based on the adsorp- tion of bitter compounds onto porous adsorbent resins (cellulose acetate or macroporous resin beads or cross-linked styrene divi- nylbenzene resins) (Shaw et al., 2000). The effectiveness of differ- ent adsorbent resins to reduce the content of bitter compounds, mainly limonin have been assessed by several authors (Lee and Kim, 2003; Kola et al., 2010), but few have reported additional ef- fects on other nutritional compounds like other flavonoids, ascor- bic acid or carotenoids. Some resins, like Dowex Optipore L285 have been reported to reduce the titratable acidity and increase the soluble solids content (Kola et al., 2010). Kimball and Norman (1990) reported that a commercial debittering system (Drow hydrophilic absorbent) reduced not only the bitter limonin con- tents by 71%, but also non-bitter flavonoids as hesperidin by 26%, in California navel orange juices. The objective of the present work was to explore the impact of the industrial DP on bioactive compounds (carotenoids and phen- olics) and on the nutritional value (provitamin A carotenoids and vitamin C) in orange juice. Additional parameters like colour and antioxidant activity were also evaluated. 0260-8774/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jfoodeng.2012.11.009 Abbreviations: DP, debittering process; OJ, orange juices; FOJ, fresh orange juice; DOJ, debittered orange juice; RAE, retinol activity equivalent; HCA, hydroxycin- namic acid derivatives; LF, lipophilic fraction; HF, hydrophilic fraction; HAA, hydrophilic antioxidant activity; LAA, lipophilic antioxidant activity. ⇑ Corresponding author. Tel.: +34 954556339. E-mail address: vicario@us.es (I.M. Vicario). Journal of Food Engineering 116 (2013) 155–161 Contents lists available at SciVerse ScienceDirect Journal of Food Engineering journal homepage: www.elsevier.com/locate/jfoodeng