Spatial distribution of dry matter in yellow fleshed cassava roots and its influence on carotenoid retention upon boiling H. Ceballos a, b, ⁎, J. Luna b , A.F. Escobar a , D. Ortiz a , J.C. Pérez a , T. Sánchez a , H. Pachón a , D. Dufour a, c a International Center for Tropical Agriculture (CIAT), Apartado Aéreo 6713, Cali, Colombia b Universidad Nacional de Colombia, Palmira Campus, Colombia c Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), UMR Qualisud, 34398 Montpellier Cedex, France abstract article info Article history: Received 2 May 2011 Accepted 3 October 2011 Keywords: Isomerization True retention Biofortification Cooking losses Lixiviation Understanding retention of carotenoids after different processing methods is important. This study was con- ducted to quantify dry matter content and carotenoids found in different sections of the cassava roots from six clones and to assess true retention of carotenoids after 30 min of boiling. Retention was quantified in nor- malized prisms taken from proximal, central and distal sectors of the root. Dry matter content (DMC) was measured along and across the roots and varied from 14.1 to 51.0%. DMC tended to be lower at the center of the root and in distal sections. DMC affected the homogeneity of the food matrix and, therefore, contribut- ed in spatial variation in retention of carotenoids. Average true retention (dry matter basis) was 86.6% and ranged from 76.0 and 96.7% (averages per clone and section of the root, respectively). Retention was positive- ly associated with carotenoid content in unprocessed samples, although the relationship was weak. The study shows that during boiling weight of samples changed from slight losses to gains of up to 40% (depending on original DMC of the uncooked root), resulting in an “apparent dilution” of the carotenoids. Results suggested the occurrence of some isomerization. All-trans β-carotene losses (13%) were partially explained by increases in the 13-cis (34%) and 15-cis (8%) isoforms, as well as lixiviation (b 1%) into the boiling water. © 2011 Elsevier Ltd. All rights reserved. 1. Introduction Vitamin A (VA), along with iron and iodine, is among the most im- portant micronutrients whose deficiency is a matter of public health concern (Underwood, 2000). It is estimated that 190 million preschool-age children have low serum retinol (b 0.70 μmol L -1 ), the sub-clinical symptom of VA deficiency (WHO, 2009). Improving the VA status of children reduces mortality rates by 23% to 30% (ACC/SCN, 1992; Beaton et al., 1993; West, 2003). There is growing evidence that VA has a positive synergistic effect with iron and zinc bio-availability (Graham & Rosser, 2000). VA is the generic descriptor for compounds with the qualitative biological activity of retinol. VA exists as preformed retinoids (retinol, retinal and retinoic acid) which are stored in animal tissue and pro-VA carotenoids, which are synthesized and stored in many green, yellow and/or orange plant tissues. Carotenoids from veg- etables contribute two-thirds of dietary VA, worldwide, and more than 80% in the developing world (Combs, 1998). Three main strategies have been traditionally used to prevent VA deficiency: dietary diversification, food fortification and/or supple- mentation. These strategies are relatively cost-effective, but have failed to completely eradicate the problem for a diversity of reasons (West, 2003). Recently, different programs such as HarvestPlus (www.harvestplus.org) and AgroSalud (www.agrosalud.org) involv- ing a global alliance of research institutions initiated the implementa- tion of a fourth strategy (biofortification) to develop micronutrient- dense staple crops (Bouis, Hotz, McClafferty, Meenakshi, & Pfeiffer, 2011; Hirschi, 2008; Montagnac, Davis, & Tanumihardjo, 2009; Nestel, Bouis, Meenakshi, & Pfeiffer, 2006; Pfeiffer & McClafferty, 2007a, 2007b; Welch & Graham, 2005). Among these initiatives is the devel- opment of biofortified cassava (Manihot esculenta Crantz) clones with high pro-VA contents in the roots. Biofortification can be achieved through conventional breeding techniques that take advantage of the genetic variability for micronutrients in different crops (Chávez et al., 2005; Welch, 2002). It represents a sustainable strategy that aims at solving the root of the micronutrient problem: a deficient diet. However, the higher micronutrient content of biofortified crops needs to be retained after processing the food (industrially and/or in the home) ultimately leading to greater absorption and use by the body. Several studies are gradually contributing to a better under- standing of carotenoid retention in different biofortified crops (Bechoff et al., 2010; Chávez et al., 2008; Li, Tayie, Young, Rocherford, & White, 2007; Maziya-Dixon, Dixon, & Ssemakula, 2009; O'Sullivan, Galvin, Food Research International 45 (2012) 52–59 Abbreviations: DMC, Dry matter content; DWB, Dry weight basis; FWB, Fresh weight basis; HPLC-DAD, High-performance liquid chromatography-diode array detec- tor; MTBE, Methyl ter-butyl ether; TBC, Total β-carotenoid; TCC, Total carotenoid con- tent; VA, Vitamin A. ⁎ Corresponding author at: International Center for Tropical Agriculture (CIAT), Apartado Aéreo 6713, Cali, Colombia. Tel.: +57 2 445 0125; fax: +57 2 445 0083. E-mail address: h.ceballos@cgiar.org (H. Ceballos). 0963-9969/$ – see front matter © 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodres.2011.10.001 Contents lists available at SciVerse ScienceDirect Food Research International journal homepage: www.elsevier.com/locate/foodres