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Foram analisados os ésteres metílicos de ácidos graxos (FAMEs) em amostras comerciais de leite empregando cromatografia gasosa acoplada ao detector por ionização em chama. Os ácidos graxos saturados (SFA) foram os mais abundantes. Os principais SFA encontrados foram o ácido palmítico (16:0), o ácido esteárico (18:0) e o ácido mirístico (14:0). Foram obtidas diferenças significativas (P < 0,500) entre as quantidades de ácido palmítico (276 ± 17 mg g -1 e 248 ± 20 mg g -1 ) e ácido mirístico (95 ± 5 mg g -1 e 85 ± 7 mg g -1 ) nas amostras analisadas. Entretanto, não foi observada uma diferença significativa para o ácido esteárico (113 ± 6 mg g -1 e 114 ± 11 mg g -1 ). O isômero conjugado do ácido linoleico (CLA) 18:2c9t11 foi detectado nas amostras e quantificado. Para este ácido, as diferenças encontradas nas amostras analisadas não foram significativas (10,4 ± 0,7 mg g -1 e 9,9 ± 0,6 mg g -1 ). A análise de uma amostra do material de referência certificado de leite (RM-8435 NIST) mostrou uma boa recuperação (> 80%) indicando que o método pode ser aplicado para determinar eficientemente ácidos graxos em amostras de leite e em produtos lácteos.Fatty acid methyl esters (FAMEs) in commercial milk samples were analyzed by gas chromatography coupled with flame ionization detection. The saturated fatty acids (SFA) were the most abundant. The major SFA were palmitic acid (16:0), estearic acid (18:0), and myristic acid (14:0). Significant differences (P < 0.500) were found between the amounts of palmitic acid (276 ± 17 mg g -1 and 248 ± 20 mg g -1 ) and myristic acid (95 ± 5 mg g -1 and 85 ± 7 mg g -1 ) in samples. However, no difference was observed for estearic acid (113 ± 6 mg g -1 and 114 ± 11 mg g -1 ). The conjugated linoleic acid (CLA) isomer 18:2c9t11 was detected in the samples and quantified. However, the differences found between the samples analyzed were not significant (10.4 ± 0.7 mg g -1 and 9.9 ± 0.6 mg g -1 ). The analysis of a certified reference powder milk sample (RM-8435 NIST) gave good recoveries (> 80%), indicating that the method can efficiently determine fatty acids in milk and dairy products.

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Pereskia aculeata Miller, known worldwide as ora-pro-nobis, is a highly nutritive species of the Cactaceae family from the Brazilian Atlantic Forest. In this work, we report inedited information on the phenolic profile of P. aculeata leaves, besides a broad study of their antioxidant potential using a set of five different methods. A total of ten phenolic compounds were identified, such as two phenolic acids (caffeic acid derivatives) and eight flavonoids (quercetin, kaempferol and isorhamnetin glycoside derivatives). Caftaric acid was the extract's major phenolic constituent, accounting for more than 49% of the phenolic content, followed by quercetin-3-O-rutinoside (14.99%) and isorhamnetin-O-pentoside-O-rutinoside (9.56%). Overall, the ora-pro-nobis leaf extract showed relevant values of antioxidant capacity, with higher activities than the Trolox in the DPPH and ABTS trials. The antimicrobial activity exhibited by the extract against both Gram-positive and Gram-negative bacteria suggests the presence of a broad spectrum of phytochemicals with antibiotic activity.