Alin Teusdea

Physical-chemical, biological, and sensory analyses in grape processing using the high frequency electromagnetic field

This paper presents the experimental results of physical-chemical, biological, and sensory analyses, obtained in processing grapes using the high frequency electromagnetic field. We processed the following varieties of grapes: Muscat Ottonel, Merlot, and Pinot Noir (harvested in the Crişana-Santimreu vineyard in 2014).

The use of the high-frequency electromagnetic field (MW) and of the pulsed electric field (PEF) for the extraction of bioactive compounds from grapes

In recent years the uses of the high-frequency electromagnetic field (MW) and of the pulsed electric field (PEF) are studied as alternative methods in winemaking for better economic efficiency and to provide high quality products, rich in bioactive compounds. The aim of our paper was to compare the two methods, MW and PEF, in terms of their applicability for the extraction of bioactive compounds from two varieties of grapes (Pinot Noir and Merlot). We also determined the antioxidant capacity of the PEF or MW treated samples, and the results were processed using multivariate analysis. Finally, we noticed that both methods are effective for the extraction of bioactive compounds, but PEF treatments determine the highest rate of extraction of bioactive compounds.

Effect of forage preservation method on fatty acid composition and oxidative stability of organic sheep milk

The aim of this study was to evaluate the effect of different forage preservation method in mountainous areas on the relationship between the fatty acid (FA) profile, fat-soluble antioxidants contents and oxidative stability of organic sheep milk. Twenty-four multiparous Turcana ewes were randomly assigned to 3 treatments: grazed grass (G), hay grass (H), and grass silage (GS). Indoor ewes were offered ad libitum grass hay or grass silage. All animals received 300 g DM grain mix (triticale and barley,1:1) per day. Conservation of grass by drying compared with ensiling resulted in lower forage 18:2n-6, 18:3n-3 and fat-soluble vitamin concentrations. Milk from ewes grazed, has a considerably higher concentration of n-3 FA and n-6 FA but and a higher content of nutritionally beneficial trans-fatty acids (e.g. CLA; conjugated linoleic acid, VA; vaccenic acid) than milk from ewes fed hay or grass silage. In spite of lower content, milk fat 18:2n-6 and 18:3n-3 content was higher (P < 0.05) for hay than for silage diets (2.34 vs. 1.64 and 2.11 vs. 1.70 % of total FA, for hay, and silages, respectively). Forage conservation method had no clear effects on milk VA or CLA content. Compared with silage, hay diets resulted in milk containing lower (P < 0.001) α-tocopherol and retinol concentrations, but had no effect on γ-tocopherol. There was no clear association between increased levels of the α-tocopherol and retinol in milk and a lower risk of lipid oxidation (lower concentration of alondialdehyde). There was a marked effect of composition of the lipids on the oxidative stability of milk, where high concentrations of PUFA (polyunsaturated FA), especially the concentration of n-3 FA were associated with an increasing risk of lipid oxidation.

Microwave-assisted extraction as a method of improving the quality of wines

ABSTRACT The aim of this paper is to study and compare the effect of microwave-assisted extraction (MW) on the content of bioactive compounds (total phenols, flavonoids, and monomeric anthocyanins), antioxidant capacity, chromatic parameters, and sensory properties of wines derived from three varieties of grapes (Muscat Ottonel, Pinot Noir, and Merlot). The applied MW treatment resulted in a more effective extraction of bioactive compounds from grapes that were also found in a large amount in the wine compared to the untreated (control) sample. The antioxidant capacity and colour intensity of the must and wine samples was much higher compared to the control sample. The influence of MW treatment depends on the variety of grapes treated. The results indicate that MW treatment is an appropriate method to produce white and red wine through increased extraction of bioactive compounds and implicitly colour enhancement.

The bioactive compounds, antioxidant capacity, and color intensity in must and wines derived from grapes processed by pulsed electric field

ABSTRACT The aim of this work was to study the effect of pulsed electric field (PEF) treatment on the content of bioactive compounds (total phenols, total flavonoids, monomeric anthocyanin content), antioxidant capacity, color intensity (CI), and sensory quality of wines derived from three varieties of grapes (Muscat Ottonel, Pinot Noir, and Merlot). PEF treatment resulted in an increase in all bioactive compounds, and consequently, an increase in their antioxidant capacity, which was evaluated by different methods. Applying PEF treatment to red grapes resulted in obtaining wines with higher CI compared to the control sample. For a better interpretation of the results and a proper discrimination of the samples in terms of the variety of grapes and PEF treatment, multivariate analyses, such as the principal component analysis, multivariate analysis of variance, and hierarchical cluster analysis, were applied.