Ana Paula Gusso

Enhancement of microbial oil production by alpha-linolenic acid producing Yarrowia lipolytica strains QU22 and QU137

Microbial oils enriched in essential polyunsaturated fatty acids can be used as nutritional complements. In order to improve the lipid yields and lipid profiles of 2 Yarrowia lipolytica strains, the effects of medium components and culture conditions were investigated using shake flasks. Under optimized conditions (cultivation for 3 days at 25oC and 150 rpm, using peptone as a nitrogen source and glucose as a carbon source), the biomass, lipid yield, and lipid content reached 6.75 g/L, 3.48 g/L, and 51.55% for Y. lipolytica QU22, and 6.85 g/L, 3.52 g/L, and 51.38% for Y. lipolytica QU137, respectively. Using a shaking speed of 150 rpm, unsaturated fatty acids constituted 87.96% (QU22) and 87.08% (QU137) of the total lipids produced by these strains, with 9.52 and 7.86% of alpha-linolenic acid, respectively. The strains are suitable candidates for fermentation processes involving essential polyunsaturated fatty acid (PUFA) production.

COMPARAÇÃO DE DIFERENTES MÉTODOS ANALÍTICOS PARA QUANTIFICAÇÃO DE LIPÍDIOS EM CREME DE RICOTA

The complexity of each sample makes impossible to describe only one method of analysis as the best, therefore, we should consider the advantages and disadvantages of each method and relate it with the sample. The aim of this study was identify the best method for lipids quantification in ricotta cream with a comparative study of three physico-chemical methods of analysis for lipids. The methods used were Soxhelt (hot extraction, using ether as solvent), Bligh; Dyer (cold extraction with chloroform, methanol and water) and Gerber (acid hydrolysis, using sulfuric acid and isoamyl alcohol). We evaluated the method in this study, among those mentioned, which would provide greater efficiency and reproducibility. The method of Gerber had the lowest performance among the methods tested, although not statistically differ from the Soxhlet method, the reproducibility of Gerber detract this type of method. The Soxhlet method showed better reproducibility of results, and values closer to those pre-determined for this sample. Bligh; Dyer method showed the highest yield of the lipid content of the sample, so the hot extraction methods (Soxhlet) and cold (Bligh; Dyer) are those that best show the lipid content of ricotta cream analyzed.

Caracterização físico-química e perfil lipídico de queijos produzidos com leite ovino

This study aimed to characterize the cheese Pecorino Toscano, Feta and Labneh made with sheep milk as to the physicochemical and lipid profile. Cheeses were acquired and analyzed of the following types: Pecorino Toscano Fresh, with 90, 180 and 270 days of ripening, Feta and Labneh made with sheep’s milk, sold in the state of Rio Grande do Sul, Brazil. The analyzes performed were: pH, titratable acidity, protein, fat, moisture, ash and fatty acids profile. The greater pH occurred in cheeses of the Pecorino Toscano type with 180 days of ripening and Feta. Regarding the titratable acidity they showed behavior contrary to the one of the pH. The protein values ranged between 15.98 and 28.29%, being the highest values for cheeses with longer ripening time. Fat showed variation identical to protein, for which the cheeses of the Pecorino Toscano type with 180 and 270 days of ripening showed higher value. The humidity values were reversed to the ripening time, and the cheeses with 270, 180 and 90 days of ripening showed values of 25.14, 25.95 and 30.26% respectively. Ashes also were higher for ripened cheeses. Regarding the lipid profile, were identified 23 fatty acids, occurring significant difference in most of the results, including in the sum of saturated, monounsaturated and polyunsaturated fatty acids and in the ratio between unsaturated and saturated. Therefore, due to the scarcity of information on the composition of cheeses made with sheep milk, further research should be conducted to characterize these products consistently.This study aimed to characterize the cheese Pecorino Toscano, Feta and Labneh made with sheep milk as to the physicochemical and lipid profile. Cheeses were acquired and analyzed of the following types: Pecorino Toscano Fresh, with 90, 180 and 270 days of ripening, Feta and Labneh made with sheeps milk, sold in the state of Rio Grande do Sul, Brazil. The analyzes performed were: pH, titratable acidity, protein, fat, moisture, ash and fatty acids profile. The greater pH occurred in cheeses of the Pecorino Toscano type with 180 days of ripening and Feta. Regarding the titratable acidity they showed behavior contrary to the one of the pH. The protein values ranged between 15.98 and 28.29%, being the highest values for cheeses with longer ripening time. Fat showed variation identical to protein, for which the cheeses of the Pecorino Toscano type with 180 and 270 days of ripening showed higher value. The humidity values were reversed to the ripening time, and the cheeses with 270, 180 and 90 days of ripening showed values of 25.14, 25.95 and 30.26% respectively. Ashes also were higher for ripened cheeses. Regarding the lipid profile, were identified 23 fatty acids, occurring significant difference in most of the results, including in the sum of saturated, monounsaturated and polyunsaturated fatty acids and in the ratio between unsaturated and saturated. Therefore, due to the scarcity of information on the composition of cheeses made with sheep milk, further research should be conducted to characterize these products consistently.