Use of Nile tilapia (Oreocromis niloticus) processing residues in the production of pâtés with the addition of oregano (Origanum vulgare) essential oil.

The effect of the use of Nilo tilapia filleting residues in the production of pâtés with the addition of oregano essential oil stored for 90 days at 4 °C was evaluated. For that, 5 treatments were performed as follows: TSA-control treatment; TES with the addition of sodium erythorbate; and formulation TOE1 with 600 ppm oregano essential oil; TOE2 with 1000 ppm essential oil; and TOE3 with 1400 ppm essential oil. The pâtés showed adequate technological and physicochemical characteristics and microbiological counts within the legislation standards. No significant differences were observed in the luminosity of the pâté formulations during storage, and the addition of oil contributed to the increase in a* values and stability of b* values. Regarding the lipid and protein oxidation, TOE3 showed lower values at the end of the shelf-life. The addition of essential oil did not affect the hardness and cohesiveness of the products. The fatty acids in greater amounts in the samples were linoleic, oleic, palmitic, and stearic acids. The analysis of biogenic amines indicated that only the treatments with the highest amounts of sodium erythorbate (TES and TOE1) showed losses of spermidine. It was observed that decreasing the inclusion of sodium erythorbate and increasing the inclusion of oregano essential oil resulted in a drop in cadaverine values. A total of 46 volatile compounds were detected in the samples with the highest amount of free fatty acids and all the formulations were well accepted sensorially.

Direct Methylation for Determination of Fatty Acids in Coffee Samples by GC-FID.

The direct methylation method developed in this work for coffee samples allowed the determination of fatty acids using smaller sample amounts (100 mg), lower solvent volumes (5 mL) and shorter experimental run time (~12 min). Hence, the experiments are more economical and collaborate with green chemistry, besides favoring the health of the analyst who handles a smaller amount of solvents in a short period. Design Expert software was employed to determine the optimal concentration of the acid and base (0.7 e 1.75 molL-1) and evaluate the sonication time (5 min for both procedures). The experiments were carried out on different coffee samples in which the fat content ranging from 10.18% to 14.86%. The relative standard deviation values for intraday and interday were 2.78% and 7.8%, respectively, confirming the good precision of the proposed method for fatty acid derivatization.