Caracterização dos grãos, torta e óleo de três variedades de girassol (Helianthus annuus L.) e estabilidade do óleo bruto
Abstract (Summary)The production of sunflower and the consumption of its oil has grown significantly in the last years in Brazil, due to the growing demand of the agro-industrial and commercial sectors and the superior oil quality. The use of screw-press for extracting sunflower oil becomes an alternative for small producers cultivating grains of high oil content, adding value to the culture. In this study, seeds, crude oil and cake of three sunflower varieties (catissol, EMBRAPA 122 and a hybrid variety), cultivated in organic system, were studied. Nutricional, fatty acid and tocopherol composition and oxidative stability were determined. Oil kept at room temperature in amber-colored glass bottles was monitored monthly for the first three months and then fortnightly until six months of storage. The peroxide value, specific extinction (232 and 270 nm) acid value and smoke point were determined according to the AOCS methodology. Oil stability was evaluated through accelerated oxidation (Schaal Oven Test). According to the results obtained, significant differences on nutritional composition among the studied varieties were observed. For accelerated oxidation tests, the highest oxidative stability was observed for oil obtained from Catissol, which presented the highest total tocopherol content. After six months of storage, peroxide value ranged from 0,2 to 7,2 meq/Kg; specific extinction at 232 and 270 nm ranged from 1,8 and 0,3 to 5,0 and 1,8 respectively; acid value ranged from 0,6 to 0,8 mg KOH/g; smoke point ranged from 180oC to 140oC. After six months of storage the oil was still suitable for consumption, with peroxide and acid value in accordance with the Brazilian legislation regarding crude oils (peroxide value of 15 meq/Kg and acid value of 4,0 mg KOH/g), but not suitable for frying due to its low smoke point (140oC).
Advisor:Roseane Fett; Jane Mara Block
Source Type:Master's Thesis
Date of Publication:02/24/2007