Leomar Hackbart da Silva

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).

Desenvolvimento de massa alimentícia fresca funcional com a adição de isolado protéico de soja e polidextrose utilizando páprica como corante

The trend of the current consumer is to use foods that are easy to prepare and that besides having nutritional quality provide health benefits. In this work, fresh food with functional characteristics was developed incorporating Soy Protein Isolate (SPI) and polidextrose using paprika as the coloring agent. The consumption of IPS could contribute to decrease cholesterol levels while polidextrose, acting as a fiber, could promote the reduction of risk of colon cancer. The optimization of the formulation was carried out using a 23 complete factorial design considering independent variables the following contents: i) SPI; ii) polidextrose; and iii) paprika. The effects of these variables on the quality of the food were evaluated through physical-chemical characteristics (color and cooking test), instrumental texture, and sensory analysis. Regarding the physical parameters, instrumental color of the raw pasta was affected only by the addition of paprika. The parameters cooking time (2.5 minutes), increase in mass (1.40 to 1.64%), and loss of solids (3.80 to 5.56%) were not influenced by the ingredients used. Elasticity (instrumental texture parameter) was reduced with the increase of polidextrose. Regarding sensory analysis of the raw food, an increase in the addition of SPI and a reduction in the addition of polidextrose positively affected global acceptance and purchase intention. An increases in SPI and paprika increased color acceptance. Regarding sensory analysis of the cooked food, SPI had a positive effect on texture while polidextrose and paprika negatively affected this parameter. Nevertheless, the ingredients used did not influence purchase intention of the cooked food. The ideal percentages of polidextrose, soy protein isolate, and paprika were 3.5, 8.0, and 1.5%, respectively.