MARCOS VIEIRA DA SILVA

Título da Dissertação: EFEITO DO PROCESSAMENTO E DO ARMAZENAMENTO NAS CONCENTRAÇÕES DE ÁCIDOS GRAXOS E ANTIOXIDANTES EM PÃO DE FORMA COM ÓLEO DE LINHAÇA

Orientador: Prof. Dr. Jesuí Vergílio Visentainer

Data da Defesa: 26/08/2011

RESUMO GERAL

INTRODUCTION. In Western diet is common the consumption of products with hydrogenated vegetable fats, which are sources of saturated and monounsaturated fatty acids, including trans fatty acids, undesirable to health. In this group of products are manufactured pan breads, very popular, and often daily. For this reason there is interest in including in their formulation compounds that enhance its nutritional quality, such as polyunsaturated fatty acids omega-3, consumed infrequently, but important because of its major representative, linolenic acid, be strictly essential, and related to anti-inflammatory and the balance of cholesterol in the human body. Flaxseed is one of the most abundant plant sources of alpha-linolenic acid.
AIMS. The aims of these work were to evaluate the effects of substitution of hydrogenated vegetable fat by flaxseed oil in the formulation of pan bread, and the resulting chemical and sensory changes, and the impact of processing on the composition of omega-3 fatty acids, omega-6 and trans, the content of phenolic compounds and antioxidant activity, and storage in the concentration of these fatty acids.
MATERIAL AND METHODS. Three formulations of pan breads were prepared in a professional bakery: FI, with hydrogenated vegetable fat, FII, with hydrogenated vegetable fat and flaxseed oil in equal proportions, and FIII, with linseed oil. Were performed to analyze chemical composition of fatty acids by gas chromatography with capillary column, of total phenolics, flavonoids and antioxidant activity by spectrophotometric methods, sensory acceptance, specific volume and instrumental color.
RESULTS AND DISCUSSION. The average content of ash (2.14%), protein (14.01%), total lipid (3.12%) and carbohydrate (80.73%) were similar between the three formulations (P > 0.05). The concentrations of saturated fatty acids, monounsaturated and trans were inversely proportional to the amount of flaxseed oil in the formulation, while poly-unsaturated and omega-3 ratio was directly proportional. The trans fatty acids were reduced to 214.04 mg.g-1 from FI, to 3.44 mg.g-1 in FIII, while the omega-3 fatty acids increased from 9.04 mg.g-1 to 335.17 12mg.g -1, improving the ratios n-6/n-3 from 19.84 to 0.61. FIII would be able to supply 22.00% of the recommended daily intake of omega-3 per serving, for an adult male, and 31.99% for an adult female. The baking reduced the concentrations of n-6 and n-3, and more intensely in FIII, decreasing to 96.64% and 89.17%. There was no significant change in the concentration of n-3 fatty acids, n-6 and trans during storage (P > 0.05). The amount of flaxseed oil in the formulation and baking increased the content of phenolic compounds in the pan bread. Flavonoids and antioxidant activity were not detected in the formulations. Measures of instrumental color and specific volume were similar (P > 0.05) among the three formulations, as well as the sensory attributes of appearance, color, texture. Only the flavor and aroma of FIII showed lower acceptance compared to other formulations, but the overall acceptance did not differ among the formulations, whose acceptability indexes were higher than 79.72%.
CONCLUSION. The substitution of hydrogenated vegetable fat by flaxseed oil was effective in the increasing of the composition of omega-3 fatty acids, so the consumption of this pan bread may be beneficial to human health.
KEY WORDS: pan bread, flaxseed, fatty acids.

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