rXXXX American Chemical Society A dx.doi.org/10.1021/jf2003317 | J. Agric. Food Chem. XXXX, XXX, 000–000 ARTICLE pubs.acs.org/JAFC Evaluation of Red Chicory Extract as a Natural Antioxidant by Pure Lipid Oxidation and Yeast Oxidative Stress Response as Model Systems Anna Lante,* ,|| Tiziana Nardi, || Federico Zocca, || Alessio Giacomini, and Viviana Corich Department of Agricultural Biotechnology, University of Padova, Padova, Italy ABSTRACT: The search for renewable and abundant sources of antioxidants has recently focused on agricultural byproducts, especially promising due to their natural origins and low costs. In particular, plant raw materials are sources of important compounds such as dietary fiber, carotenoids, tocopherols, and polyphenolics, which are mostly discarded during harvesting and processing. Among these vegetal crops, red chicory is attractive because of the large quantity of its byproducts (residues as leaves and stems); moreover, there is no information on its role as a food and feed ingredient. In this study, red chicory leaf residue was evaluated as a natural substitute for synthetic antioxidants for the food and feed industry. After lyophilization, a red chicory extract (RC) was characterized for its phenolic profile and its oxidative stability as compared to BHT. RC was shown to reduce lipid peroxidation of different oils in the Rancimat test. In addition, the antioxidant property of RC was studied in a model system by evaluating the Saccharomyces cerevisiae response to oxidative stress by means of gene expression. In this analysis, the RC extract, added to the yeast culture prior to oxidative stress induction, exhibited a pleiotropic protective effect on stress responsive genes. KEYWORDS: red chicory, natural antioxidants, lipid peroxidation, Saccharomyces cerevisiae, oxidative stress ’ INTRODUCTION There is an emerging interest in the use of naturally occurring antioxidants for the preservation of feeds and foods for both their technological relevance and their positive impact on consumer health. In this context, several foregoing studies have pointed out strength relationships between diet and chronic diseases: Phy- tochemicals present in fruits and vegetables may have antioxidant effects, thus protecting them from oxidative damage arising from metabolic and exogenous sources. 13 Lipid oxidation is not an exclusive concern for the food industry but also occurs in feeds and feedstuffs, resulting in rancidity of fats, degradradation of proteins, vitamins, and pigments, and cross- linking of lipids and other macromolecules into non-nutritive polymers with a serious decrease in the nutritional value. The addition of exogenous antioxidants is a well-known strategy; although hundreds of them have been tested, only a few chemicals have shown the qualifications necessary to make them suitable for use in preventing undesirable oxidations in food and feed. An antioxidant must have the following qualifications: (a) it must be effective in preserving animal and vegetable fats, vitamins, and other food and feed qualities subject to oxidative damage; (b) it must be nontoxic to man and to animals; (c) it should be effective at very low concentrations; and (d) it must be low enough in cost to be economically convenient. Among the chemical compounds that have been investigated thus far, BHA and BHT have been demonstrated to be the most efficacious in both the food and feed industries. As these antioxidants are suspected to be promoters of carcinogenesis, 4 the public concern about their safety demands the evaluation of alternative substances. The growing interest in the replacement of synthetic food antioxidants by natural ones has led to multiple investigations in the field of new antioxidants. The search for cheap, renewable, and abundant sources of antioxidants has focused on raw materials of residual origin, especially promising due to their low costs. 5 Moreover, the residuals can be valuable resources for those new business models that are already competing in the emerging market of eco-products and/or healthy foods. Agricultural byproducts contain a variety of biologically active substances, which mostly go to waste, but these are also promising sources of compounds as dietary fibers, carote- noids, tocopherols, and polyphenolics. Among the bioactive com- pounds, phenolics play an important role because, in contrast to most carotenoids and vitamins, they are not chemically synthesized and need to be extracted from plant material. Moreover, recycling of the byproduct has been supported by the observation that poly- phenols are located specifically in the peels. 6 In this respect, grape skin extracts are being marketed for their anthocyanin and procya- nidin contents. 7 Studies on di fferent chicory varieties have demon- strated that they are an interesting source of natural antioxidants. 8 Moreover, chicory is promising because of the large availability of its byproducts. Indeed, before commercialization, large amounts of wastes and residues (leaves, stems, etc.) are produced, which can reach 4050% of the harvested material, and there is no information on their role as food and feed ingredients. 9 The aim of this study is to evaluate red chicory (RC) extract as a natural antioxidant for the food and feed industries. In this work, the chemical composition and oxidative stability of a lyophilized RC extract were investigated. Moreover, the RC extract effect on eukaryotic stress response by means of Sacchar- omyces cerevisiae expression (SCE) analysis has been studied as a Received: January 25, 2011 Revised: April 12, 2011 Accepted: April 13, 2011