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María R Alberto

Publications and source records attributed to María R Alberto.

3 recordsLinked to original sources

Metabolism of gallic acid and catechin by Lactobacillus hilgardii from wine.

The ability of Lactobacillus hilgardii 5w to metabolize gallic acid and catechin was evaluated. It was grown in a complex medium containing gallic acid or catechin. The metabolites were analyzed by high-performance liquid chromatography and identified by comparing the retention times and spectral data with the standards of a database. In gallic acid-grown cultures, gallic acid, pyrogallol, catechol, protocatechuic acid, p-hydroxybenzoic acid, p-hydroxybenzaldehyde, and p-hydroxybenzyl alcohol were detected. In catechin-grown cultures, catechin, gallic acid, pyrogallol, catechol, p-hydroxybenzoic acid, acetovanillone, and homovanillic acid were detected. This work presents evidence of gallic acid and catechin degradation by L. hilgardii from wine.

Adsorption↗

Differences between biogenic amine detection by HPLC methods using OPA and dansyl derivates.

Biogenic amines can be formed and degraded as a result of normal metabolic activity in animals, plants, and microorganisms and are usually produced by the decarboxylation of amino acids. Recent trends in food security are promoting an increasing search for trace compounds that can affect human health. Although they are present in fermented foods and beverages in low quantities, they exhibit interactions with normal human metabolism (e.g., having vasoactive or psychoactive properties) that justify the research on their presence in foods and the possible related toxicological effects that they may cause. Estimation of the biogenic amines histamine, tyramine, agmatine, putrescine, and cadaverine is important not only from the point of view of their toxicity, but also because they can be used as indicators of the degree of freshness or spoilage of food. Until recently, because of the difficulty in detecting and quantifying amines reliably we have had insufficient information about their occurrence in different types of foods and beverages. These problems are related to matrix interference (e.g., the presence of free amino acids) and the low levels at which the amines are found. Early techniques for the determination of biogenic amines in foods were based on thin-layer chromatography. More modern analytical techniques have since been developed that allow the acquisition of reliable quantitative data and better separation/resolution of various amines. The quantitative determination of biogenic amines is generally accomplished by overpressure-layer chromatography, high-performance liquid chromatography (HPLC), and gas chromatography. The use of reverse-phase column and precolumn derivatization was more efficient and faster than the conventional ion-exchange techniques. This study was conducted to evaluate two HPLC derivatization methods for quantitative determination of biogenic amines: the method described by Gonzales de Llano et al. for amino acid analysis and the method described by Eerola et al.

Biogenic Amines↗

Effect of wine phenolic compounds on Lactobacillus hilgardii 5w viability.

After 6 days of Lactobacillus hilgardii 5w incubation at 4 degrees C, the viable cell counts diminish 31.9, 45.6, and 89.0% when suspended in control wine (2,600 mg/liter gallic acid equivalents [GAE]), three-fold concentrated wine (6,150 mg/liter GAE), and six-fold concentrated wine (13,000 mg/liter GAE), respectively. At 20 degrees C in the same conditions, the cell viabilities decrease 74.2, 80.5, and 100.0%, respectively. In decolorized wines, which result in tannin losses, the viable cell counts increase. There is a relationship between L. hilgardii 5w tannin binding and its viability loss.

Color↗