Comprehensive metabolomics to evaluate the impact of industrial processing on the phytochemical composition of vegetable purees Patricia Lopez-Sanchez a,⇑,1 , R.C.H. de Vos b,e,f,1 , H.H. Jonker b,e,f , R. Mumm b,f , R.D. Hall b,e,f , L. Bialek a , R. Leenman a , K. Strassburg d,e , R. Vreeken d,e , T. Hankemeier d,e , S. Schumm a , J. van Duynhoven a,c,e,2 a Unilever Research and Development, Olivier van Noortlaan 120, 3133 AT Vlaardingen, The Netherlands b Plant Research International, Wageningen University and Research Centre, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands c Laboratory of Biophysics, Wageningen University and Research Centre, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands d Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands e Netherlands Metabolomics Centre, Einsteinweg 55, 2333 CC Leiden, The Netherlands f Centre for Biosystems Genomics, P.O. Box 98, 6708 PB Wageningen, The Netherlands article info Article history: Received 13 March 2014 Received in revised form 11 July 2014 Accepted 14 July 2014 Available online 24 July 2014 Keywords: Metabolomics Vitamins Tomato Broccoli Carrot Puree Processing LC–MS GC–MS NMR LC–MRM MS abstract The effects of conventional industrial processing steps on global phytochemical composition of broccoli, tomato and carrot purees were investigated by using a range of complementary targeted and untargeted metabolomics approaches including LC–PDA for vitamins, 1 H NMR for polar metabolites, accurate mass LC–QTOF MS for semi-polar metabolites, LC–MRM for oxylipins, and headspace GC–MS for volatile com- pounds. An initial exploratory experiment indicated that the order of blending and thermal treatments had the highest impact on the phytochemicals in the purees. This blending-heating order effect was investigated in more depth by performing alternate blending-heating sequences in triplicate on the same batches of broccoli, tomato and carrot. For each vegetable and particularly in broccoli, a large proportion of the metabolites detected in the purees was significantly influenced by the blending-heating order, amongst which were potential health-related phytochemicals and flavour compounds like vitamins C and E, carotenoids, flavonoids, glucosinolates and oxylipins. Our metabolomics data indicates that during processing the activity of a series of endogenous plant enzymes, such as lipoxygenases, peroxidases and glycosidases, including myrosinase in broccoli, is key to the final metabolite composition and related quality of the purees. Ó 2014 Elsevier Ltd. All rights reserved. 1. Introduction A high intake of fruit and vegetables is recommended by health authorities worldwide due to a potential relationship with a reduced risk of cancer and cardiovascular diseases (Crowe et al., 2011; Leenders et al., 2013). Led by the consumers demand for more natural and healthier products, the food industry aims to (re)design manufacturing processes for improved nutritional qual- ity of products based on fruit and vegetables. Carrot, tomato and broccoli are good sources of antioxidant vitamins (Steinmetz & Potter, 1996), next to many other phytochemicals that are potentially healthy for human, like various flavonoids and phenyl- propanoids (Moco et al., 2006; Vallejo, Tomas-Barberan, & Ferreres, 2004). Broccoli also contains considerable amounts of glucosino- lates, a group of phytochemicals specifically found in brassica vegetables (Moreno, Carvajal, Lopez-Berenguer, & Garcia-Viguera, 2006). During food manufacture phytochemicals may undergo thermal degradation, air exposure due to disruption of plant tissues/cells and endogenous enzymatic activity. For example, vitamin C can be easily lost, especially during cooking, due to its sensitivity to heat (Francisco, Velasco, Moreno, Garcia-Viguera, & Cartea, 2010). Semi-polar phytonutrients like flavonoids and glucosinolates can also be lost upon heating vegetables (Aires, Carvalho, & Rosa, 2012; Francisco et al., 2010). In contrast, there is generally a relatively high retention of hydrophobic compounds such as b-carotene during thermal treatments (Svelander, Lopez-Sanchez, Pudney, Schumm, & Alminger, 2011). Furthermore, not only the retention but also the bio- accessibility of health related compounds can be influenced by http://dx.doi.org/10.1016/j.foodchem.2014.07.076 0308-8146/Ó 2014 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. Present address: ARC Centre of Excellence in Plant Cell Walls, CNAFS, The University of Queensland, St. Lucia 4072, Queensland, Australia. Tel.: +61 733460793; fax: +61 733650539. E-mail addresses: p.lopezsanchez@uq.edu.au (P. Lopez-Sanchez), john.van. duynhoven@wur.nl (J. van Duynhoven). 1 Both authors contributed equally to this work. 2 Tel.: +31 317482044; fax: +31 317482725. Food Chemistry 168 (2015) 348–355 Contents lists available at ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem