Lireny Aparecida Guaraldo Gonçalves

Oil Wastes as Unconventional Substrates for Rhamnolipid Biosurfactant Production by Pseudomonas aeruginosa LBI

Oil wastes were evaluated as alternative low‐cost substrates for the production of rhamnolipids by Pseudomonas aeruginosa LBI strain. Wastes obtained from soybean, cottonseed, babassu, palm, and corn oil refinery were tested. The soybean soapstock waste was the best substrate, generating 11.7 g/L of rhamnolipids with a surface tension of 26.9 mN/m, a critical micelle concentration of 51.5 mg/L, and a production yield of 75%. The monorhamnolipid RhaC10C10 predominates when P. aeruginosa LBI was cultivated on hydrophobic substrates, whereas hydrophilic carbon sources form the dirhamnolipid Rha2C10C10 predominantly.

Oxidative stability of fermented goat meat sausage with different levels of natural antioxidant

Goat meat was used for fermented sausage processing. The oxidative stability of the fermented goat meat sausage, containing two different levels of natural antioxidant (rosemary-Rosmarinus officinalis), at room temperature, was evaluated by way of periodical analyses for thiobarbituric reactive substances (TBARS), overall acceptance and descriptive sensory profile, for 90 days. The initial values for TBARS indicated that lipid oxidation occurred during the processing of the fermented sausages. Significant correlations were not found between the TBARS values and the sensory analysis, except for an oxidized aroma in the control sample and the overall acceptance after 75 days of storage. Formulations containing 0.05% rosemary showed the best characteristics in relation to oxidative stability, with the lowest initial values for TBARS, the greatest sum for the overall acceptance sensory, highest values for red color and lowest scores for oxidized aroma and flavor, when compared with the sample containing 0.025% rosemary.

Dynamic impregnation of silica stationary phases for the argentation chromatography of lipids

Abstract Homogeneous silver-impregnated thin-layer chromatographic (TLC) plates were obtained in a dynamic manner by chromatographing an acetonitrile solution of silver nitrate on ready-made silica TLC plates. Plates obtained in this manner are very reproducible. Separations according to the number of double bonds in the individual triglycerides on dynamically impregnated plates are equal to or better than those obtained on silver nitrate TLC plates prepared in the conventional manner. The plates are easier to handle, and savings in silver nitrate result in comparison with the dipping procedure. It is possible to impregnate a plate simultaneously with both phloxin and silver in one run, the immobilized phloxin then serving as a fluorescence detection agent for a subsequent triglyceride separation and for semi-quantitative densitometry. Silica high-performance liquid chromatographic columns can also be impregnated with silver nitrate in a similar dynamic manner.

Interesterificação química: alternativa para obtenção de gorduras zero trans

The function of lipids in human nutrition has been intensively debated in the last decade.This context reinforces the concern about controlling the trans fat ingestion, due to its negative implications on health. Interesterification provides an important alternative to modify the consistency of oils and fats without causing formation of trans isomers. This article reports research done towards production of zero trans fats by chemical interesterification, for different industrial purposes. Aspects related to the effect of trans fats on diet, their impact on health and modifications in Brazilian legislation are also covered.

Modificação por via enzimática da composição triglicerídica do óleo de piqui (Caryocar brasiliense Camb)

Piqui (Caryocar brasiliense Camb) oil was transformed into a cocoa butter-like fat through an enzymatic interesterification reaction using Lipozyme in the presence of stearic acid that was incorporated in the sn 1,3-3,1 position into triglyceride. Stearic acid incorporation was determined by HPLC, based on the quantification of the principal triglycerides (POP, POS e SOS) found in cocoa butter. The proposed process was feasible with a reaction time of 240 minutes with 10% of Lipozyme at 70oC and substract weight ratio of 0,33 (stearic acid:piqui oil).

Refining of rice bran oil (Oryza sativa L.) to preserve γ-orizanol

γ-orizanol is an antioxidant present in rice bran oil, but absent in other vegetable oils, which were attributed to antioxidant and hypocholesterolemic effects. The content of γ-orizanol in crude rice bran oil varies between 1-2%, but during neutralization in chemical refining this substance is transferred to soapstock. The aim of this research is to study an alternative technique of physical refining in light conditions with the purpose of preserving γ-orizanol. Inativacted and extrused rice bran obtained by the production of parboilizated rice was used to extract crude rice bran oil (Oryza sativa) by the expeller method. The process of refining consisted of: acid degumming (with 85% H3PO4), centrifugation, clarification, deodorization, and winterization. Chemical analyses were carried out by the characterization of refined oil according to the AOCS methods. Results showed that the physical refining process was able to preserve 97% of γ-orizanol, and its presence improved the oxidative stability of the oil comparing with the commercial rice bran oil (by 33% 13.3 hours to 110 oC).

Otimização da reação de interesterificação química do óleo de palma

The Brazilian market has been showing a growing concern with nutritional values of oil components of foods. Chemical interesterification is a promising alternative to the current processes of modifying the consistency of oils. Chemical interesterification of deodorized palm oil was studied on a laboratory scale. The best results were obtained with 0.4% MeONa and heating for 20 min at 100 °C. These conditions are based on the largest variation in triacylglycerols as compared to a control. The trisaturated values varied from 6.2 to 9.9%, showing that the consistency of the oil improved for it to be used in margarines, without the formation of trans isomers.

Quantificação de TBHQ (terc butil hidroquinona) e avaliação da estabilidade oxidativa em óleos de girassol comerciais

Sunflower oil is one of the vegetable oils most susceptible to oxidative reaction. Therefore the presence of natural (tocopherol) and/or synthetic (TBHQ) antioxidants is a prerequisite to secure the stability of this oil during its shelf life, especially with the increased use of PET packaging. On determining the total tocopherol content in 10 samples of deodorized sunflower oils, high losses in total tocopherol during deodorization were identified. In order to facilitate researche involving oxidative stability of vegetable oils, a method for isolated quantification of TBHQ using the isocratic elution system was developed.

Efeito do teor de gordura nas características químicas e sensoriais de embutido fermentado de carne de caprinos

The objective of this study was to verify the effect of the addition of different fat contents (5, 10 and 20%) in the processing, chemical characteristics and sensory acceptance of a goat meat fermented sausage. During processing, pH and water activity were measured. Moisture, protein and fat contents were determined in final products, as well as sensory acceptance by hedonic scale. Final average values of pH and water activity, which ranged from 5.07 to 5.14 and 0.897 to 0.923 respectively, showed no significant difference (P>0.05) among any of all treatments. There were no significant differences (P>0.05) for any of all measured sensory attributes. No different percentage of fat in manufacturing of goat meat fermented sausage significantly affected its processing and sensory acceptance. Due to low fat content in goat meat, 10 to 20% of fat level were considered as the most adequate.

Evaluation of the quality of pet foods using fast techniques and official methods

This paper was designed to evaluate the rancidity of 18 pet food samples using the Diamed FATS kits and official AOCS methods for the quantification of free fatty acids, peroxide value and concentrations of malonaldehyde and alkenal in the lipid extracted. Although expiration dates have passed, the samples presented good quality evidencing little oxidative rancidity. The results of this study suggest that the Brazilian pet food market is replete with products of excellent quality due to the competitiveness of this market sector.