Análise da concentração de retinol em fígados de galinhas submetidos a diferentes processamentos térmicos

Abstract

In Brazil, the production and consumption of giblets are under development, in particular the liver, which is the source of nutrients considered to be a rich source of vitamin A. This vitamin is a micronutrient that plays an essential role in vision, growth, development and maintenance of the epithelial tissue, and in immunological processes in reproduction. Being a food easy acquisition and low commercial value, the chicken liver is a bet to combat vitamin A deficiency (VAD), which affects mainly children and pregnant women in developing countries. This study aimed to analyze the concentration of retinol by high performance liquid chromatography (HPLC) in livers of farms of chickens, organic and hillbillies in different conditions of thawing and cooking, marketed in the city of Natal/RN. In addition, this study aimed to validate an adaptation of the methodology proposed by Hosotani & Kitawaga (2003) for retinol analysis in this food so that the method of analysis become simple, fast and cheap. The mean values of retinol in farm chicken liver for the three brands analyzed were: 9152,9 ± 719; 4673,1 ± 389; 5943,6 ± 614 mg/100 g (p < 0,05). The average retinol organic chicken liver was 3401,33 ± 597,12 g / 100 g. The average retinol in hillbilly chicken liver was 30094.79 ± 4628,75 g/100 g. It was observed that the baking oven for 35 minutes at 200 ° C and thawing process in microwave for one minute caused a significant loss of 39,9 % (p < 0,05) and 26,2 % (p < 0,01), respectively, the retinol concentration in farm chicken liver. The method validation technique resulted in a rapid extraction and determination and quantification need retinol in chicken liver samples, with an average retention time of 5,2 minutes at 23 ° C, with excellent results linearity (R = 0,9999 ) standard stock stability and freeze-thaw process accurately coefficient of variation below 15% and recovery with values of 93 % to 101,2 %. Despite significant losses in thermal processes, consumption of an average serving of roasted liver (88 g) supplies the daily requirement of vitamin A for a man over 14 years up to 6 times and 20 times the daily needs of children 1 to 3 years. The study showed a significant difference between farm livers brands as well as free-range and organic chicken livers, and a significant loss in the retinol content in chicken livers when subjected to thermal processing. The validated method is suitable and safe for retinol analysis in this type of food.