Oil quality characterization of the Arauco variety from the main olive growing areas of Mendoza (Argentina)

‘Arauco’ forms part of the over two thousand olives (Olea europaea L.) varieties identified worldwide with the peculiarity of being the only recognized variety from Argentina. In this work, the fruit and oil characteristics from the ‘Arauco’ variety cultivated in the three main olive growing zones of Mendoza province (Argentina) were evaluated over two harvests (2016 and 2017). The characteristics assessed were oil and water concentrations, pulp/pit ratio, industrial yield, oxidative stability, fatty acid profile, total phenols and total flavonoids, among others. The results showed relatively high oleic acid and phenolic contents, together with low acidity and extinction coefficients (K232 and K270), as well as a well-balanced fatty acid profile. In addition, three interesting relationships among oxidative stability and ratios of monounsaturated fatty acids/polyunsaturated fatty acids (R2=0.96), oleic/linoleic (R2=0.96) and stearic acid (R2=0.93) were observed. These results showed that the ‘Arauco’ variety cultivated in Mendoza provides excellent oil quality.

Comparative study of the physicochemical properties of a vegan dressing-type mayonnaise and traditional commercial mayonnaise

The food industry has developed a vegan dressing-type mayonnaise due to new consumer demands. The aim of this study was to compare three commercial mayonnaise types with a vegan dressing, measuring their physicochemical properties. Four dressing samples were analyzed: vegan, homemade recipe, creamy, and light. The following properties were measured: water activity, color, droplet size, rheological properties, structural analysis, and oxidative stability. A high color difference was observed between vegan and the other samples due to the presence of chickpea protein. The size and distribution of droplets of the vegan sample were greater than the others. The rheological properties indicated that all samples are non-Newtonian pseudoplastic fluids. The FT-IR results indicated that the highest peak for vegan corresponded to its content in mono-unsaturated fat. Therefore, it showed the lowest oxidative stability. In conclusion, the mayonaise formulations were affected by physicochemical properties such as the content and composition of the oil, thickener and protein contents, along with processing technology.

Comparison of a Rapid Light-Induced and Forced Test to Study the Oxidative Stability of White Wines

The oxidation processes of white wines can occur during storage and commercialization due to several factors, and these can negatively affect the color, aroma, and quality of the wine. Wineries should have faster and simpler methods that provide valuable information on oxidation stability of wines and allow fast decision-making procedures, able to trigger suitable technological interventions. Using a portable prototype instrument for light irradiations at different wavelengths and times was considered and evaluated on sensorial, spectrophotometric, and colorimetric parameters of white wines. The sensorial analysis revealed that white and light blue were the most significant, after only 1 h of irradiation. The experimental results showed that hydrogen peroxide could enhance the effect of light treatment, allowing a contemporary evaluation of the oxidation stability of wine against light and chemical stresses. As expected, a good correlation (R2 > 0.89) between optical density at 420 nm and b* parameter was highlighted. The synergic effect of light and H2O2 was also studied on the hydrolyzable and condensed tannins’ additions to white wine. The proposed methodology could be used to evaluate the oxidative stability of white wines, but also to evaluate the effect of some oenological adjuvants on wine stability.

Biochemical characterization of olive oil samples obtained from fruit mixtures and from oil blends of four cultivars grown in Central Tunisia

Blends of olive oils obtained from four cultivars (Olea europaea L. cv. Chemlali, Chetoui, Oueslati and Koroneiki) were produced by two different methods of blending: processing fruit mixtures or mixing monovarietal oils, using the same proportions of selected cultivars. The obtained blends were biochemically characterized to evaluate quality, and the two methods were compared. The results indicated that the most successful formulations are mainly F8 (60% Chemlali × 20% Oueslati × 20% Koroneiki) characterized by the highest contents of phenols and an elevated oxidative stability, and F5 (50% Chemlali × 50% Koroneiki) containing the highest MUFA level and the highest oxidative stability. The effect of the blending process on pigments and volatiles cannot be easily regulated, unlike phenols, fatty acid composition and OS, all of which positively correlated to the fruit mass ratio in the blend. Results suggest that processing fruit mixtures of different cultivars resulted in a better oil quality than that of oils obtained by the common oil blending method. This blending procedure offers a possibility to modulate the contents of antioxidants, fatty acids and volatile compounds in virgin olive oil, and therefore, its quality and sensorial characteristics.