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- Natural antioxidants in emulsions O/WPublication . EL-GEUNDOUZ, Soukaina; Azza, S.; Dandlen, Susana Anahi; MAJDOUB, Nesrine; Lyoussi, Badiaa; Raposo, Sara; Gomes, Vera; Bankova, Vassya; Popova, Milena; Antunes, Maria Dulce; Miguel, Maria GracaThis study compared the capacity of propolis extract (PE) and thyme waste extract (TWE) to prevent the oxidation of oil in water (O/W) emulsion, as well as their impact on emulsion apparent viscosity (AV) in the presence of wheat germ and almond oils as lipid phase. For this, central composite design (CCD) and principal component analysis (PCA) were performed. Oxidation process was monitored by evaluating the formation of primary and secondary lipid oxidation products, at the same time the AV behavior was determined evaluating consistency index and flow behavior index. The results revealed that the increase of PE% and TWE% decreases TBARS (Thiobarbituric Acid Reactive Substances) and hydroperoxides formation. Viscosity increases with the rise of TWE% over (0.04%), whereas lower concentrations of PE% decreases it. Those results have been confirmed in the PCA analysis. TWE showed higher resistance to oxidation, although PE was more effective as antioxidant than TWE.
- Nutritional characterization and storage ability of Salicornia ramosissima and Sarcocornia perennis for fresh vegetable saladsPublication . Antunes, Maria Dulce; Gago, Custódia; Guerreiro, Adriana; Sousa, Ana Rita; Julião, Miriam; Miguel, Maria Graca; Faleiro, Maria Leonor; Panagopoulos, ThomasThe aim of this work was to study the potential of two halophytes for fresh salads. Sarcocornia perennis (SAR) and Salicornia ramosissima (SAL) plant tips were harvested in May and July, and stored at 4 °C for 14 days. At harvest, mineral analyses (Na, K, Mg, Ca, P, N, Fe, Zn, Cu, Pb and Cd), chlorophyll content, protein, β-carotene and ascorbic acid were performed. Color (CIELab), phenolics, antioxidant activity and microbial contamination were measured at harvest and after 14 days storage at 4 °C, and a taste panel evaluated the products. SAL had generally slightly higher values of vitamin C, phenols and carotenoids than SAR. In SAR after 14 days of storage, the levels of phenols and the antioxidant activity were higher than at harvest, both in May and July. The opposite was observed for SAL. In this case, only the antioxidant activity was higher after 14 days of storage. Microbial contamination was very low, not reaching even half of critical limits. Both halophytes had good nutritional value, being suitable for use as fresh salads which can be stored for up to 14 days at 4 °C. SAR seems to be a better source of antioxidants, Ca and Fe than SAL and has less general quality and nutritional value changes from harvest time through cold storage. Fresh tips of both halophytes showed better appearance and nutritional quality when harvested in the early season (May) than at the end of the season (July).
- Targeted gene disruption coupled with metabolic screen approach to uncover the LEAFY COTYLEDON1-LIKE4 (L1L4) function in tomato fruit metabolismPublication . Gago, Custódia; Drosou, Victoria; Paschalidis, Konstantinos; Guerreiro, Adriana; Miguel, Maria Graca; Antunes, Maria Dulce; Hilioti, ZoeKey message Functional analysis of tomato L1L4 master transcription factor resulted in important metabolic changes affecting tomato fruit quality. Abstract Tomato fruits from mutant lines bearing targeted disruption of the heterotrimeric nuclear transcription factor Y (NF-Y) transcription factor (TF) gene LEAFY-COTYLEDON1-LIKE4 (L1L4, NF-YB6), a master regulator of biosynthesis for seed storage proteins and fatty acids, were evaluated for metabolites content and morphology. Metabolic screens using LC-MS/MS-based analysis and physico-chemical methods in different L1L4 mutants of the fourth generation allowed a comparative assessment of the effects of the TF disruption. Mutagenesis resulted in fruits phenotypically similar to wild-type with subtle shape differences in the distal end protrusion and symmetry. Conversely, mutant fruits from independent lines had significant variation in moisture content, titratable acidity and overall metabolite profiles including oxalic and citric acid, fructose, beta-carotene, total polyphenols and antioxidants. Lines 6, 7 and 9 were the richest in beta-carotene and antioxidant activity, line 4 in ascorbic acid and lines 4 and 8 in succinic acid. The reduced content of the anti-nutrient oxalic acid in several mutant fruits suggests that L1L4 gene may regulate the accumulation of this compound during fruit development. Detailed LC-MS/MS analysis of mutant seeds showed substantial differences in bioactive compounds compared to wild-type seeds. Taken together, the results suggest that the L1L4 TF is a significant regulator of metabolites both in tomato fruit and seeds providing a molecular target for crop improvement. Elucidation of the candidate genes encoding key enzymes in the affected metabolic pathways aimed to facilitate the L1L4 gene network exploration and eventually lead to systems biology approaches in tomato fruit quality.