A comparative study on oxidative and hydrolytic stability of monovarietal extra virgin olive oil in bakery products Francesco Caponio ⁎, Mariagrazia Giarnetti, Carmine Summo, Vito M. Paradiso, Lucrezia Cosmai, Tommaso Gomes Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti (Di.S.S.P.A.), Università degli Studi, Via Amendola, 165/a, I-70126 Bari, Italy abstract article info Article history: Received 20 March 2013 Received in revised form 28 May 2013 Accepted 24 June 2013 Keywords: Extra virgin olive oil Cultivar Oxidative degradation Shelf-life Volatile compounds An experimental investigation was carried out with the aim to assess the influence of the chemical character- istics of the extra virgin olive oil used in dough formulation of bakery products on the evolution of hydrolytic and oxidative lipid fraction degradation, by means of the determinations of free fatty acids, peroxide value, specific absorption at 232 and 270 nm, as well as volatile and polar compounds. At this purpose, three differ- ent monovarietal extra virgin olive oils, cultivars Bosana, Coratina and Ogliarola barese (named Ogliarola), having different chemical composition, were tested and used in the taralli production recipes. The obtained data showed that oxidized triacylglycerols significantly increased during storage irrespective of the oils used in dough formulation, whereas peroxide value, K 232 and polar compounds significantly increased only in taralli prepared with Bosana oil; all others parameters did not show significant differences. In any case, a different lipid degradation was observed in function of the utilized oils. In particular, when Coratina oil was used, a significant lesser oxidative degradation was observed, probably due to both the higher content of antioxidants (total phenols and carotenoids) and the lower content of substances characterized by pro-oxidant activity (oxidized triacylglycerols and diacylglycerols) than those of Bosana and Ogliarola oils. The results of the volatile compounds confirm the more susceptibility to oxidation of taralli made with Bosana oil. The research assessed the importance of the chemical composition of extra virgin olive oil used in the ingredient formulation of taralli. © 2013 Elsevier Ltd. All rights reserved. 1. Introduction Fats play a key role in bakery products. The choice of fat for the preparation of bakery goods is driven not only by nutritional needs of consumers, but also by the need of obtaining the desired rheological properties and the contribution of specific sensory properties (aroma, flavor, softness, volume, palatability, bright appearance), as well as to stabilize the products toward oxidation reactions, stale, and moisture migration (Pagani, Bottega, & Mariotti, 2010). The fats usually used in the preparation of bakery products are butter, lard, hydrogenated vege- table oils, margarine and refined oils. Previous researches highlighted that it is possible to improve the quality of the lipid fraction of bakery products. In particular, taralli manufactured with extra virgin olive oil, which is at the base of the Med- iterranean diet, were significantly more appreciated by consumers than those made with the more frequently used refined oils, due to their visu- al appearance and odor (Caponio, Giarnetti, Summo, & Gomes, 2011). Moreover, with respect to the other kinds of oil, the use of extra virgin olive oil led to significantly lower values of triacylglycerol oligopolymers (TAGP) and a much lower content of oxidized triacylglycerols (ox-TAG) and diacylglycerols (DAG) than olive pomace oil and refined palm oil re- spectively (Caponio, Giarnetti, Paradiso, Summo, & Gomes, 2013). It is well known that the products of oil oxidation are considered potentially toxic to consumers' health (Billek, 2000; Saguy & Dana, 2003). Further- more, trans fatty acid isomers, that have negative effects on the consumers' health (Koletzko & Decsi, 1997; Morrison, Glueck, & Wang, 2008; Willett & Ascherio, 1994), were absent in taralli made with extra virgin olive oil but were constantly present in those produced with refined oils. Giarnetti, Caponio, Paradiso, Summo, and Gomes (2012), in a study carried out to investigate on the evolution of the volatile profile of taralli as a function of both the kind of oil used in the dough and the storage time, demonstrated that the kind of oil plays an important role on the formation and on the release of aroma compounds. In fact, the volatile compounds significantly increased during storage and their individual levels were in most cases significantly lower in taralli made with extra virgin olive oil than in those made with refined oils. The chemical composition of the virgin olive oil is a result of differ- ent variables, such as (i) environmental, climatic, soil and cultivation conditions, age of the tree, olive ripeness and healthy status (Aparicio & Luna, 2002; Caponio, Gomes, & Pasqualone, 2001; Salvador, Aranda, & Fregapane, 1999); (ii) transport and storage conditions (Gimeno, Food Research International 54 (2013) 1995–2000 ⁎ Corresponding author at: Università degli Studi, DiSSPA, Sezione di Scienze e Tecnologie Alimentari, Via Amendola 165/a, I-70126 Bari, Italy. Tel./fax: +39 080 5443467. E-mail address: francesco.caponio@uniba.it (F. Caponio). 0963-9969/$ – see front matter © 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.foodres.2013.06.022 Contents lists available at ScienceDirect Food Research International journal homepage: www.elsevier.com/locate/foodres