Ana Valente

Effect of UV-C radiation on bioactive compounds of pineapple (Ananas comosus L. Merr.) by-products.

BACKGROUND The industrial processing of pineapple generates a high quantity of by-products. To reduce the environmental impact of these by-products and the inherent cost of their treatment, it is important to characterise and valorise these products, converting them into high added value products. Ultra-violet radiation is one of the main sustainable sanitation techniques for fruits. Since this radiation can induce plant stress which can promote the biosynthesis of bioactive compounds, it is important to evaluate its effect in fruits. RESULTS The amounts of vitamins (C and E) and carotenoids (α-carotene, β-carotene, β-cryptoxanthin, lutein, lycopene, neoxanthin, violaxanthin and zeaxanthin) in pineapple by-products (core and rind) were analysed before and after treatment with UV radiation. All treated and untreated pineapple by-products contained β-carotene as the main carotenoid (rind, 2537-3225 µg; and core, 960-994 µg 100 g(-1) DW). Pineapple rind also contained lutein (288-297 µg 100 g(-1) DW) and α-carotene (89-126 µg 100 g(-1) DW). CONCLUSION The results provide evidence of the potential of pineapple by-products as a source of bioactive compounds with antioxidant activity, which can be used by pharmaceutical, cosmetics and food industries. In addition, UV-C was shown to be a treatment that can add nutritional value to pineapple by-products.

Validation and clinical application of an UHPLC method for simultaneous analysis of total homocysteine and cysteine in human plasma

Several studies indicate that high levels of homocysteine (Hcy) and L-cysteine (L-Cys) are independent risk factors for cardiovascular disease. The validation and clinical application of an ultra HPLC method for analysis of Hcy and L-Cys is described. The reported method is simple, sensitive, rapid, precise, and less aggressive than other previously reported methods. The effect of the derivatization reaction time, pH, and organic solvent contents in the mobile phase are described and discussed. Optimized conditions resulted in excellent peak shapes. Results of method validation showed a good linearity (r(2) ≥ 0.993) over the investigated concentration ranges and were observed for both compounds. The LOD and LOQ were 0.05 μM and 0.15 μM for Hcy and 0.24 μM and 0.80 μM for L-Cys, respectively. Validation results proved that the method precision was good and the accuracy was satisfactory. This validated method was successfully applied in an epidemiological study to measure and compare the prevalence of Hcy and L-Cys high levels in plasma of Portuguese type 2 diabetic patients with and without angiopathy. The study results showed that prevalence of hyperhomocysteinemia and hypercysteinemia were at least two times higher in diabetic patients with angiopathy compared to diabetics without angiopathy.

Carotenoids, vitamins (A, B2, C and E) and total folate of traditional foods from Black Sea Area countries

BACKGROUND Carotenoids, vitamins (A, B2, C and E) and total folate are related to health promotion. However, there are still many food matrices for which the content of these compounds is not available. In order to fill this gap, traditional foods from Black Sea Area countries (BSAC) were analysed in order to investigate their potential health benefits. RESULTS The most abundant carotenoid was β-carotene. Plum jam was the sample with the highest β-carotene content (608 µg 100 g(-1) edible portion). The group of vegetables and vegetable-based foods contributed most to β-carotene content. Evergreen cherry laurel presented the highest l-ascorbic acid content (29.9 mg 100 g(-1) edible portion), while the highest riboflavin and total folate contents were found for roasted sunflower seeds. Approximately 61% of the analysed samples showed quantifiable amounts of α-tocopherol but did not contain retinol. CONCLUSION Despite the great variability in the content of carotenoids, vitamins and total folate, most of the analysed traditional foods from BSAC can be considered good sources of these compounds. Therefore, owing to their putative health benefits, the consumption of those with higher contents of these compounds should be encouraged and promoted.