Phytochemical content in organic and conventionally grown Italian cauliflower Valentina Picchi a,⇑ , Carmela Migliori a , Roberto Lo Scalzo a , Gabriele Campanelli b , Valentino Ferrari b , Luigi Francesco Di Cesare a a Agricultural Research Council (C.R.A.) – Research Unit of Food Technology (C.R.A. – I.A.A.), Via G. Venezian 26, 20133 Milan, Italy b Agricultural Research Council (C.R.A.) – Research Unit for Horticulture (C.R.A. – O.R.A.), Via Salaria 1, 63030 Stella di Monsampolo, AP, Italy article info Article history: Received 30 November 2010 Received in revised form 12 May 2011 Accepted 12 July 2011 Available online 19 August 2011 Keywords: Cauliflower Organic and conventional farming Phytochemicals Glucosinolates Volatile substances Antioxidants abstract An experiment was conducted that compared the phytochemical content of two genotypes (Emeraude and Magnifico) of a green typology cauliflower under conventional or organic management. In addition, three fertilisation regimes were considered within the framework of organic agriculture. The two geno- types showed a contrasting response to organic practices: the phytochemical content of Emeraude was generally reduced, while in Magnifico, most of the quality parameters were unaffected or increased. In addition, under organic management, the use of higher fertilisation levels significantly increased the phy- tochemical production of Magnifico, in particular ascorbic acid (P < 0.05) and polyphenols (P < 0.01). However, the same fertigation treatments decreased the phytochemical production of Emeraude, partic- ularly glucosinolates and ascorbic acid. This genotype was identified as a key factor in the determination of cauliflower quality under different management practices. Moreover, our results indicate that the addition of fertilisers to organic soil might be effective only with a cauliflower genotype suited to organic agriculture. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction Phytochemicals are studied for their physiological role in plants, such as in stress response and resistance to diseases, and their abil- ity to increase agronomic performances. In addition, together with the commonly measured quality parameters (dry matter, soluble solid residue and titratable acidity), they represent an important quality parameter because of their positive effect on human health. Among vegetables, cauliflower (Brassica oleracea, L., subsp. Botrytis) is particularly rich in phytochemicals, such as glucosinolates, vita- min C, polyphenols, and, to a minor extent, carotenoids. Glucosin- olates, formed by a glycone (which contains thioglucose and sulphonated oxime) and an aglycone (which is derived from amino acids such as methionine, phenylalanine, tyrosine and tryptophan), are hydrolysed to glucose and isothiocyanates by myrosinase (b- thioglucoside glucohydrolase) (Fenwick, Heaney, & Mullin, 1983). Some isothiocyanates (e.g., 3-methylsulphonilpropyl NCS, 4-meth- ylsulphonilbutyl NCS or sulphoraphane, and 3-indolylmethyl NCS) can produce sulphur and nitrogen compounds during vegetable cooking, which are the characteristic volatile substances of cooked Brassicaceae (VanEtten & Daxenbichler, 1977). Glucosinolates and the products of their hydrolysis (isothiocyanates) are produced by plants in response to specific biotic stressors, such as fungi, bac- teria, nematodes and insects attacks (Troncoso, Espinoza, Sánchez- Estrada, Tiznado, & García, 2005). In the context of human health, they are known to protect against cancer (Verkerk, van der Gaag, Dekker, & Jongen, 1997). Cauliflower contains large amounts of sul- phoraphane, indole-3-carbinol and 2-propenyl isothiocyanates, which are the breakdown products of glucoraphanin, glucobrassi- cin and sinigrin, respectively (Fig. 1)(Agerbirk, De Vos, Kim, & Jan- der, 2009). Vitamin C, which includes ascorbic acid (Fig. 1) and its oxida- tion product, dehydroascorbic acid, is involved in many biological activities, both in plants and in animals. Vitamin C is the most abundant hydrophilic antioxidant in plants where it directly detox- ifies ROS (Reactive Oxygen Species). Additionally, it may play a role as an indirect antioxidant, providing reducing power to (ascorbate) peroxidases and repairing the tocopheroxyl radical of vitamin E, thereby restoring its antioxidant activity (Padh, 1990). Moreover, the high antioxidant capacity of vitamin C is responsible for the slowdown of cellular aging (Wada & Ou, 2002). In human health, vitamin C is relevant for the prevention of cancer, cardiovascular and chronic inflammatory diseases, hypertension and diabetes (Bremus, Herrmann, Bringer-Meyer, & Sahm, 2006). Phenolic compounds are a large group of secondary metabolites that are categorised into classes based on their structure. The common feature of these compounds is the presence of relatively labile hydrogen atoms that are able to neutralise or quench free radicals. Thus, polyphenols are recognised as powerful antioxi- dants (Rice-Evans, Miller, & Paganga, 1997). Fruits and vegetables are the richest potential sources of these substances. In fact, 0308-8146/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodchem.2011.07.036 ⇑ Corresponding author. Tel.: +39 02 239557204; fax: +39 02 2365377. E-mail address: valentina.picchi@entecra.it (V. Picchi). Food Chemistry 130 (2012) 501–509 Contents lists available at SciVerse ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem