Browsing by Author "Castro, Matilde L. F."
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- Content and distribution of conjugated linoleic acid isomers in bovine milk, cheese and butter from AzoresPublication . Pestana, Jose M.; Martins, Susana I. V.; Alfaia, Cristina M. M.; Lopes, Paula A.; Costa, Ana S. H.; Bessa, Rui J. B.; Castro, Matilde L. F.; Prates, Jose A. M.Pasture intake is a major factor affecting the content and the distribution of the conjugated linoleic acid (CLA) isomers in bovine milk fat. The aim of this study was to determine the CLA contents and its isomeric distribution in milk, cheese and butter
- 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
- Irradiation effect on fatty acid composition and conjugated linoleic acid isomers in frozen lamb meatPublication . Alfaia, Cristina M. M.; Ribeiro, Paulo J. L. C.; Trigo, Maria J. P.; Alfaia, Antonio J. I.; Castro, Matilde L. F.; Fontes, Carlos M. G. A.; Bessa, Rui J. B.; Prates, Jose A. M.The effect of gamma radiation processing on the lipid content, fatty acid composition and conjugated linoleic acid (CLA) profile in frozen lamb meat was investigated. Samples of longissimus thoracis muscle from lambs fed lucerne basal diets either unsupplemented or Supplemented with polyunsaturated vegetable oils were irradiated (7 kGy) and analysed. CLA contents in lamb meat did not affect (P 0.05) the levels of lipid oxidation induced by the irradiation. No significant differences (P 0.05) were observed for fatty acid composition, related nutritional indexes (n - 6/n - 3 and PUFA/SFA), as well as for total lipid and CLA contents, between non-irradiated (control) and irradiated meat samples. In contrast, meat irradiation affected the relative proportions of total trans, trans and cis/trans CLA isomers (P 0.001), in addition to the percentage of some minor individual CLA isomers (t11,t13 and t9,t11, with P 0.05 and P 0.001, respectively). The percentage of total cis/trans CLA isomers slightly decreased in irradiated samples, while the relative proportion of total trans, trans isomers slightly increased. This observation may be explained by the higher susceptibility to autoxiclation of the cis double bond relative to the trans configuration. (c) 2007 Elsevier Ltd. All rights reserved.