Amalia A. Carelli

Chemical quality and oxidative stability of extra virgin olive oils from San Juan province (Argentina)

This study provides information about the chemical quality (quality indices, fatty acid profile, total polyphenols (PPs), tocopherols and pigments) and oxidative stability index (OSI) of virgin olive oils of Arbequina, Changlot Real and Coratina cultivars (San Juan province, Argentina). The influence of the cultivar and the effect of earlier harvest dates on the yields (OY), quality and OSI of the oils were also evaluated. All the oils were classified as extra virgin. The OY (L/100kg) averaged: Arbequina=13.2, Changlot Real=21.3, Coratina=18.3. The oleic acid (O) percentage, oleic to linoleic plus linolenic ratio [O/(L+Ln)], PPs and OSI were highly dependent on cultivar (Arbequina<Changlot Real<Coratina). The earlier harvest season associated with lower maturity indices increased the OSI of all the oils (Arbequina: from 6.3-13.8h up to 10.6-19.0h, Changlot: from 6.0-12.1h up to 13.7-36.9h and Coratina: from 20.5-26.0h up to 24.6-42.4h) due to a more favorable O/(L+Ln) ratio and antioxidant composition. Regional producers are recommended to bring forward the harvest season to obtain oils with better chemical and nutritional quality, higher oxidative stability and a fatty acid profile according to the IOC trade standard.

Emulsions of sunflower wax in pectin aqueous solutions: Physical characterization and stability

The knowledge of the stability and physical properties of film-forming solutions is necessary for optimizing the process design of films. In order to evaluate their applicability for the production of edible films, the rheological and microstructural properties, particle size and physicochemical stability of aqueous emulsions of low methoxyl pectin and sunflower waxes from normal and high-oleic hybrids were assessed. Emulsions were prepared with different pectin concentrations (1, 2 and 3% w/w) and wax proportions (0.1, 0.2 and 0.3 g/g pectin). The rheological behavior was best described by the power law model. The values of the behavior index (n) were close to 1, exhibiting a behavior close to Newtonian fluids. The addition of waxes caused an increase in viscosity and shear stress. The particle size of the emulsions made with waxes from high-oleic sunflower was smaller than those from the normal hybrid. In most cases, size distributions with greater height and less amplitude were obtained, mainly when the pectin content was higher. Confocal images allowed to observe the presence of waxes and their dispersion in the pectin matrix. Destabilization phenomena such as sedimentation, coalescence and creaming were observed at long test times independent of the wax origin. These results evidence the potential use of these emulsions for the manufacture of edible films.

Solvent-free enzymatic hydrolysis of non-polar lipids in crude sunflower lecithin using phospholipase A1 (Lecitase® Ultra)

Abstract In this contribution, a new chromatographic method was applied to study the hydrolysis of non-polar lipids, i.e. triacylglicerols (TAG), diacylglycerols (DAG) and monoacylglycerols (MAG), when crude sunflower lecithin is treated with Lecitase® Ultra, an enzymatic preparation with phospholipase A1 (PLA1) activity. Results not only proved the enzyme lipase activity toward non-polar lipids in selected reaction conditions (aqueous system, T = 50 °C, pH = 5) but also suggested the occurrence of acyl-migration phenomenon observed by other authors in similar systems. Results showed that 1 h of reaction was enough to decrease the content of TAG in 54%, while DAG and MAG concentration increased from 0.4 to 3.5 and from 1.9 to 6.5 g/100 g of crude lecithin, respectively. Along the reaction, different contents of glycerides could be achieved, obtaining products with different composition which, in combination with the presence of phospholipids (PL) and/or lysophospholipids (LPL), could present specific emulsifying/stabilizing properties with a wide range of applications in food and pharmaceutical industry.