L. Lopes

Nutritional quality of the protein of Vigna unguiculata L. Walp and its protein isolate

A protein’s true digestibility and amino acid composition are important characteristics for its nutritional characterisation. This study determined the true digestibility of the protein from cowpea (Vigna unguiculata L. Walp.) and of its protein isolate, and their nutritional values were estimated after correcting for the amino acid score. The protein was isolated from the defatted whole bean by its alkaline solubilisation and isoelectric precipitation. The amino acid composition of the protein from the whole bean and from the isolate was determined by ion-exchange chromatography. Protein digestibility was assessed by the nitrogen balance method. The amino acid score is the lowest value obtained from the ratio between the individual amount of each essential amino acid present within the protein and the recommendation of each one for preschool infants. Methionine was the limiting amino acid in both the whole bean and the isolate. The true digestibility of the protein corrected by the amino acid score is an estimate of its nutritional value. The amino acid score for the whole bean was 0.44, and protein digestibility was 86.7%. For the isolate, these values were 0.60 and 96.7%, respectively. Correcting each score by the digestibility resulted in an estimated nutritive value of 38% and 58% for the whole bean and the isolate, respectively. Therefore, by having higher digestibility and increasing the bioavailability of essential amino acids, cowpea protein isolate is of interest for inclusion in food products, especially cereal-based products, which contain lysine as a limiting amino acid and are rich in methionine.

Cholesterol-Lowering and Liver-Protective Effects of Cooked and Germinated Mung Beans (Vigna radiata L.)

We investigated the hypocholesterolemic and liver-protective effects of cooked and germinated whole mung beans. Hamsters were fed for 28 days on diets rich in saturated fatty acids and cholesterol, differing only in protein source (20%): casein, cooked whole mung bean, and germinated mung bean. After 28 days, we found reduced plasma concentrations of total cholesterol and non-HDL cholesterol, increased faecal cholesterol excretion, and reduced levels of asparagine aminotransferase and alanine aminotransferase enzymes in the liver. Reduction in hepatic lipid deposition was observed between each of the mung bean groups relative to the casein group. In addition, the animals of the geminated mung bean group showed a lack of inflammatory infiltrate and better vascularisation of the hepatic tissue. Results from this study show significant hypocholesterolemic and liver-protective properties of the mung bean, which are further enhanced after germination.

P45. HIPERPARATIROIDISMO PRIMÁRIO SECUNDÁRIO AO LÍTIO: A PROPÓSITO DE UM CASO CLÍNICO

Introducao: A terapeutica com litio esta indicada no tratamento da doenca bipolar. Para alem de uma maior incidencia de bocio e de hipotiroidismo, o uso prolongado de litio esta associado a varias consequencias metabolicas, nomeadamente a hipercalcemia e o hiperparatiroidismo (HPT). Caso clinico: Mulher, 64 anos, com antecedentes de doenca bipolar e HTA. Medicada com litio, quetiapina, bisoprolol e enalapril. Recorre a nossa consulta em Agosto de 2008 por BMN conhecido desde ha varios anos e por niveis de calcio elevados. Sem historia conhecida de litiase renal. Na consulta e-lhe confirmado um BMN (com citologia benigna dos nodulos) e um hiperparatiroidismo primario (calcio 10,6, fosforo 2,06, PTH 256, clearance creatinina 73 ml/min, calciuria e funcao tiroideia sem alteracoes). Cintigrafia das paratiroides com sestamibi negativa. Osteodensitometria ossea com evidencia de osteopenia (Tscore -2,0) ao nivel da extremidade distal do radio. Medicada com acido alendronico 70 mg/semana. A hipotese de diagnostico mais provavel foi BMN e HPT secundarios ao litio (HPTL). Por nao ser possivel parar o litio, decidiu-se manter vigilância. Apos 1 ano, verifica-se franco agravamento da hipercalcemia (calcio: 12,8). Repete sestamibi, que mostra um aumento da captacao do radiofarmaco ao nivel da paratiroide inferior esquerda, razao pela qual e proposta para cirurgia. Em Jan/2010 e submetida a tiroidectomia total e paratiroidectomia inferior esquerda. O DH revelou um adenoma da paratiroide com 13 × 12 × 8 mm e uma hiperplasia folicular, multinodular da tiroide. Pos operatorio com normalizacao do calcio e reducao da PTH. Inicia terapeutica com levotiroxina 12 5ug/dia e mantem litio. Durante 1 ano, a doente manteve niveis de calcio normais e de PTH discretamente elevados. Repetiu sestamibi que foi negativo. Atualmente, mantem-se em vigilância na consulta de Endocrinologia, mantendo terapeutica com litio. Discussao: O HPTPL pode afectar uma ou varias paratiroides, pelo que o tratamento cirurgico nao e consensual. A individualizacao da terapeutica e essencial, sendo frequentemente necessaria uma exploracao bilateral. O rastreio atempado e vigilância do HPTL e essencial em doentes sob terapeutica com litio, permitindo uma reducao das comorbilidades associadas.