Total carotenoids and antioxidant activity of fillets and shells (in natura or cooked) of “Vila Franca” shrimp (Litopenaeus Schmitti) in different intervals of storage under freezing

ABSTRACT Shrimps are sources of carotenoids, astaxanthin is the predominant, responsible for their special and desirable properties, as well as for their instability under heat treatment during the domestic preparation, industrial processing or storage under freezing. These can cause discoloration and reduce the beneficial health properties. This study aimed to evaluate the effect of heat treatment and storage under freezing (0, 45 and 90 days) on the levels of total carotenoids and stability of the antioxidant activity of ethanolic extracts of fillets and shells, raw and cooked, of the white shrimp (“Vila Franca”) Litopenaeus schmitti (Burkenroad, 1938). The antioxidant ability of the extracts was evaluated using the radicals DPPH• (2,2-diphenyl-1-picryl-hydrazyl) and ABTS+• (2,2’-azino-bis (3-ethylbenzothiazoline-6 sulfonic acid), as well as by the iron reducing power (FRAP) test. The extracts of cooked or in natura shrimps (fillets and shells) represent dietary sources of carotenoids, displaying antioxidant activity through all the tested methods, after heat treatment and storage under freezing. The antioxidant activity of the extracts was superior to the one of ascorbic acid, mainly in the cooked fillet and shells. The samples of shrimp shells seemed a valuable source of carotenoids, whose antioxidant activity was verified even 90 days after freezing, and can be used in food products as functional natural supplement, adding value to this waste. RESUMO Os camarões são fontes de carotenóides, sendo a astaxantina o predominante, responsáveis por suas propriedades especiais e desejáveis, e também a causa da sua instabilidade pelo tratamento térmico durante o preparo doméstico, processamento industrial ou armazenamento sob congelamento, que pode causar descoloração e redução de suas propriedades benéficas à saúde. Este trabalho visou avaliar o efeito do tratamento térmico e armazenamento sob congelamento (0, 45 e 90 dias) nos teores de carotenóides totais e na estabilidade da atividade antioxidante dos extratos etanólicos de filé e cascas, cruas ou cozidas, de camarão “Vila Franca” Litopenaeus schmitti (Burkenroad, 1938). A capacidade antioxidante dos extratos foi avaliada utilizando os radicais DPPH• (2,2-difenil-1-picril-hidrazila) e ABTS+• (2,2’-azino-bis-(3-etilbenzotiazolina-6- acido sulfônico), bem como pelo teste do poder redutor do ferro (FRAP). Os extratos do camarão cozido ou in natura (filé e cascas), representam fontes dietéticas de carotenóides