Artículos de Revistas

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https://repositorio.uft.cl/handle/20.500.12254/2470

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Examinando Artículos de Revistas por Materia "06 - Producción y tecnología industrial"

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    Adsorption of low molecular weight food relevant polyphenols on cross-linked agarose gel
    (Elsevier, 2021-10-25) Rivera-Tovar, Pamela Raquel
    Adsorption of five relevant low molecular weight polyphenols identified in agro-industrial waste extracts (Aristotelia chilensis leaves, Carménère wine pomace, spent coffee grounds, and brewery waste streams) was measured and characterized. SuperoseTM 12 prep grade and between three and six solutions with different water, ethanol, and acetic acid compositions were used as adsorbent and liquid phases. The chosen adsorbent and liquid phases were relevant for designing an adsorption preparative liquid chromatography (APLC) process to isolate these polyphenols. Langmuir and Freundlich models adequately fitted the obtained isothermal equilibrium data. The Freundlich model represented better ferulic acid (FA), kaempferol (KAE), and resveratrol (RSV) adsorptions, while the Langmuir model represented better gallic acid (GA) and catechin (CAT). Different polyphenol/agarose affinities in water-rich liquid phases were observed. From this, a hypothetical elution order was established (KAE < GA < FA < CAT < RSV), which was partially experimentally corroborated (for a mixture of GA, CAT, and RSV) with an APLC system. Lowering the water proportion or increasing the EtOH:HAc ratio in the liquid phase reduced the adsorption of these polyphenols, except for FA. The decrease in adsorption with temperature and the negative values of ΔH indicated that these processes were exothermic. The adsorption of all the polyphenols was governed by physisorption. All the adsorption processes studied were spontaneous and thermodynamically feasible (ΔG < 0). In addition, the polyphenol molecules were less randomly organized (more ordered) at the polyphenol/agarose interface during the adsorption process (ΔS < 0).
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    Functional fermented cherimoya (Annona cherimola Mill.) juice using autochthonous lactic acid bacteria
    (Elsevier, 2020-09-07) Isas, Ana Sofía
    The biochemical and functional properties of fermented Annona cherimola Mill. (cherimoya) juice using five lactic acid bacteria (LAB) isolated from autochthonous fruits from Northwestern Argentina were studied in this work. Fermentation was carried out at 30 °C for 48 h followed by a 21 day-storage period at 4 °C. The assayed LAB grew well during fermentation (final count of 108 CFU/mL, ΔpH ca. 1 U) and survived after the storage period. All strains consumed fructose and glucose present in cherimoya juice as energy sources, with the consequent synthesis of lactic and/or acetic acids as final metabolic products. However, only two of the five evaluated strains were capable to produce fermented cherimoya juices with a perceptible color change. Due to lactic acid fermentation, a moderate reduction in the total phenolic content (between 13% and 43%) was observed in the majority of the samples, although no change in the antioxidant capacity was detected. The fermented cherimoya juices showed a weak antiplatelet activity when adenosine diphosphate agonist was used. The findings of this study evidenced the potential use of Annona cherimola Mill. fermented juice as a novel matrix for the formulation of stable functional beverages with appealing nutritional and functional properties.
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    In house validation for the direct determination of 5-hydroxymethyl-2- furfural (HMF) in “dulce de leche''
    (Elsevier, 2020-10-01) Barrera, Josefina
    In this work an HPLC-DAD determination method for free and total HMF in “dulce de leche” was developed and validated. The separation was carried out using a mobile phase of acetonitrile-water (4.5:95.5, v/v) on Acclaim™120 C18 (4.6 × 150 mm, 5 μm), at 30 °C and a flow rate of 1 mL/min. The detection was done at 284 nm.The method showed good selectivity and linearity (determination coefficient over 0.999). Low LOD and LOQ values were obtained (19.51 μg/L and 65.05 μg/L respectively). Relative standard deviation (RSD) for repeatability and intermediate precision was <4.12 % and <5.98 % respectively. Recovery rates were between 89.04 % and 91.89 %. In addition, the HMF contents in commercial “dulce de leche” from Chile was reported, ranging from 2.33 to 10.31 mg/kg for free HMF and 314.61–464.98 mg/kg for total HMF.
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    Multi-response optimal hot pressurized liquid recovery of extractable polyphenols from leaves of maqui (Aristotelia chilensis [Mol.] Stuntz)
    (Elsevier, 2021-03-29) Rivera-Tovar, Pamela Raquel
    Multi-response optimization of hot pressurized liquid extraction (HPLE) was applied for the first time to obtain maqui (Aristotelia chilensis [Mol.] Stuntz) leaf extracts. The total polyphenol content (TPC), the antioxidant capacity (AC) as well as the total polyphenol purity of the maqui leaf extracts were accurately predicted (RSD < 8%) at the evaluated extraction scales. The optimum HPLE conditions that prioritized TPC and AC equally (OPT1) recovered ~3 times more TPC (205.14 mg GAE/g leaves) than maqui leaf extracts obtained by maceration, while the extract that prioritized purity over TPC and AC presented the highest purity (36.29%) and an EC50 ~3 times lower than currently reported values. It was found by multi-response optimization that maqui leaves and HPLE are among the best natural sources and extraction techniques, respectively, to recover protocatechuic acid, quercetin, and catechin.