DMF - Comunicações em Actas de Conferências
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- Gamma irradiation effect on fatty acid composition and conjugated linoleic acid isomers of lamb meatPublication . Alfaia, Cristina M. M.; Ribeiro, Paulo J. L.; Castro, Matilde L. F.; Bessa, Rui J. B.; Prates, José A. M.The perception of quality and "healththiness" of food has become the most important factor for decision. ln meat, this aspect is largely related to its fat content and fatty acid composition. Some meat fatty acids play important roles in metabolism and human health. Recent interest in a minor group of fatty acids that are characteristic of ruminant fat, named conjugated linoleic acid (CLA), is also of great nutritional and bíological consideration. One of the major concerns with the existing technologies for food preservation, including irradiation, is that these processes may enhance lipid oxidation and thereby affect meat qualíty . There are attempts to enforce irradition not only for food safety, but also for technological purposes. Even though irradiation is a prospective technology, its application causes physical-chemical and biochemical changes, that may affect nutritional value and sensory characteristics of irradiated food . The aim of this study was to evaluate the effect of gamma irradiation on fatty acid composition and contents of CLA isomers in frosen lamb meat. The major fatty acids were 18:1c9 as monounsaturated, 16:0 and 18:0 as saturated and 18:2n-6 as polyunsaturated fatty acids. No significant differences were observed in fatty acid composition between non-irradiated and irradiated meat samples. The CLA isomeric distribution showed a clear predominance of the c9,t11,c13.18:2 (10.3 and 10.1%) and t7,c9-18:2 (2.91 and 2.94%). It was found that the irradiation treatment, in contrast to the percentages of partial sums of CLA isomers (trans, trans, cis/trans and cis, cis), which showed significant differences (p<0.001), had no effect on the relative proportions of individual CLA isomers (except for the minor t11,t13.18:2 and t9,t11-18:2). In addition, and regarding the health-promoting CLA isomers (c9t11-18:2 and t10c12-18:2), the irradiation process does not negatively alter the composition and nutritional value of lamb meat
- Lipid composition and nutritional value of some meats with Protected Designation of Origin (PDO)Publication . Prates, José A. M.; Ribeiro, Verónica; Quaresma, Mário; Lourenço, Marta; Martins, Susana; Alves, Susana; Portugal, Ana; Castro, Matilde; Fontes, Carlos M. G.; Bessa, Rui J. B.; Alfaia, Cristina M.The aim of this work was to characterise and compare the lipid cQmposition (lípid and eholcsterol contents, fatty acid composition and conjugated linoleie acid isomers) and nutritiona! value (PUFA/SFA and n-6/n-3 ratios) of four Portuguese mea!s with Protceted Designation of Origin (POO; Camalentejana-PDO beel: Mertolenga-POO beef, Barrosã-POO veal and Arouquesa-POO veal), in 1\\'0 distinct slaughter seasoos (early autUnm and late spring). The purebred bovines were maintained according to the traditional productioo systems following the rules established in the meat-POO product specificatioos. ln addition, we also compared the nutritional qU31ityof illtramuscular fat in thesc meats-PDO ,vith the meat obtained from AlentejanaxCharolais erossbrcd young bulls produced io a typical intcnsive concentrate-based system. The results obtained for Carnalentejana-PDO beef (Meat Science. 2006. 72, 425-436), Mertolenga-PDO bcef (Joumal of lhe Science of Food and Agrieulture, 2006, 86, 2196-2205), Barrosã-PDO veal (Food Chemistry, 2006, 94,469-477; Meat Science, 2007, 75,44-52) and Arouquesa-PDO veal (Meat Science, submitted), indicate that intramuscular tàts of meats-PDO. as a result of the beneficial grass effects 00 the eharacterislics of meat lipids, are of grcater nutritional quality than inteosively produêcd bcef from crossbred young bulls throughout the year. However, the data suggest that beef-PDO (Camalentejana-POO aod Mertolenga-POO) iotramuseular falorelative 10Ihat fram veal-PDO (Barrosã-PDO veal and Arouquesa-PDO veal), depiets a 1m.vnutritional ql,lality throughout the year. These differences may be explained by the finishing period of Alentejana and Mertolenga purebrcd young bulls 011coneentrate, which attenuates the beneficia] effects on the charaeteristies ofmeat fat associated with grass intake