Effects of thermal processing on fatty acids, phytosterols and other chemical properties of black table olives

Abstract

Black table olives are a popular food and highly appreciated for its taste, typically used in pizzas, salads and other meals. Among the compounds present in this food are the bioactive lipids like monounsaturated fatty acids (MUFAs) and phytosterols, related to the prevention of the occurrence of some chronic diseases. Pasteurization may be applied to black table olives aiming to ensure its microbiological quality, but this processing can cause undesired degradation of thermosensitive organic compounds. This work aimed to evaluate the changes that occur in chemical properties, fatty acids profile, and phytosterols in Azapa black table olives after pasteurization. The olives were treated at 80 °C for 5 min, which achieved a lethality factor F62.4ºC equal 40 min. Fatty acids and phytosterols determination were carried out using a Gas Chromatography with Flame Ionization Detector (GC-FID). Other components were analyzed by physicochemical determinations. The results demonstrate that Azapa black table olives are a source of unsaturated fatty acids (72.33g.100 -1 g) and total phytosterols (137.4 mg.100 -1 g), substances associated with beneficial health effects. Pasteurization did not promote chemical changes (p>0.05) in total protein, lipids, ash content, acidity, pH, and total chlorides in the samples, except for moisture content that had 4.1% of reduction. The fatty acid composition also was not affected (p>0,05). However, phytosterol levels were affected (p<0.05) by thermal processing, with a decrease of about 24.6% of campesterol, 16.8% of β-sitosterol, and 60.9% of stigmasterol. Data suggest that thermal processing used to treat Azapa black olives must be optimized to minimize this negative effect.