María F. Gayol

Effect of storage on chemical and sensory profiles of peanut pastes prepared with high-oleic and normal peanuts.

BACKGROUND Peanut paste and peanut butter have high oil contents and are thus susceptible to developing rancidity and off-flavours through lipid oxidation. Preservation of the chemical and sensory quality of these products is one of the main problems in the peanut industry. The purpose of this study was to compare the chemical and sensory stability of peanut paste prepared with high-oleic peanuts (cv. Granoleico, GO-P) with that of peanut paste prepared with normal peanuts (cv. Tegua, T-P) from Argentina. RESULTS Chemical (peroxide and p-anisidine values and conjugated dienes) and sensory (roasted peanutty, oxidised and cardboard flavours) indicators of lipid oxidation were measured in peanut pastes stored at 4, 23 and 40 °C. Chemical indicator values and oxidised and cardboard flavours showed lower increments in GO-P than in T-P during storage. T-P had significantly higher peroxide value than GO-P. Roasted peanutty flavour showed a lower decrease in GO-P. Peanut paste prepared with high-oleic peanuts had four (at 4 °C), two (at 23 °C) and three (at 40 °C) times longer shelf-life than peanut paste prepared with normal peanuts. CONCLUSION These results indicate that high-oleic Granoleico kernels provide peanut paste with higher protection against lipid oxidation.

Antioxidant activity of rosemary essential oil fractions obtained by molecular distillation and their effect on oxidative stability of sunflower oil

The objective of this study was to evaluate the antioxidant activity of rosemary essential oil fractions obtained by molecular distillation (MD) and investigate their effect on the oxidative stability of sunflower oil. MD fractions were prepared in a series of low-pressure stages where rosemary essential oil was the first feed. Subsequently, a distillate (D1) and residue (R1) were obtained and the residue fraction from the previous stage used as the feed for the next. The residue fractions had the largest capacity to capture free radicals, and the lowest peroxide values, conjugated dienes and conjugated trienes. The antioxidant activity of the fractions was due to oxygenated monoterpenes, specifically α-terpineol and cis-sabinene hydrate. Oxidative stability results showed the residues (R1 and R4) and butylated hydroxytoluene had greater antioxidant activity than either the distillate fractions or original rosemary essential oil. The residue fractions obtained by short path MD of rosemary essential oil could be used as a natural antioxidants by the food industry.

Highly concentrated omega-3 fatty acid ethyl esters by urea complexation and molecular distillation: Concentrated omega-3 FAEE by UC and MD

BACKGROUND Raya liver deodorized oil contains high concentrations of eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA). The present study investigated the processes of urea complexation (UC) and molecular distillation (MD) to determine the most adequate operation conditions for each process, separately and together, aiming to obtain highly concentrated EPA, DPA and DHA ethyl esters with chemical indicator values permitted by the current legislation for edible oils. RESULTS In the second stage of MD, a concentration of 820.27 g kg-1 in the distillate and 951.06 g kg-1 of omega-3 fatty acid ethyl esters in the residue was obtained. The distillate showed values of free fatty acids, peroxide and p-anisidine lower than the maximum allowed for edible oils in accordance with the current legislation. CONCLUSION The use of UC and MD together has revealed a significant improvement in the total concentration of omega-3 fatty acid ethyl esters in the final product and good application prospects.

Sensory quality of milk fat with low cholesterol content fractioned by molecular distillation

BACKGROUND Anhydrous milk fat (AMF) is a valuable ingredient in several industries, but its cholesterol content is a disadvantage because it is associated with several diseases. The objective of this study was to remove the largest possible amount of cholesterol from AMF by molecular distillation and to analyze the sensory properties of the obtained product. AMF was subjected to various molecular distillation arrangements. RESULTS The first set of experiments involved molecular distillations performed over a range of evaporation temperatures. Then, according to the outcome of the first set of experiments, a second set of experiments was carried out in order to study the effect of the feeding flow rate. Finally, the number of distillation stages was modified. CONCLUSION The best results were obtained in a three-stage arrangement, in which ∼60% of cholesterol was removed with a 30.48% distillate yield. The sensory properties of this distillation cut were also the most similar to those of the untreated milk fat.