Giselda Macena Lira

Influence of seasonality on the chemical composition of oysters (Crassostrea rhizophorae).

This paper aimed to evaluate the influence of seasonality on the chemical composition of oysters (Crassostrea rhizophorae). Samples were collected during summer and winter from the estuary and lagoon complex of the municipality of Barra de São Miguel, Alagoas, Brazil. Statistical differences (p<0.05) between summer and winter were observed in relation to chemical composition. The oysters cultivated in the winter presented some nutritional advantages because of the higher levels of proteins and functional nutrients, such as the eicosapentaenoic-docosahexaenoic acid combination and percentages of polyunsaturated fatty acids (n-3 and n-6), and the lower levels of saturated fatty acids. Therefore, the animals in winter presented a higher content of cholesterol oxides. The levels of cholesterol oxides found in these products during winter may encourage researchers to investigate the composition of oysters cultivated in different climates all over the world.

Efeito do beneficiamento sobre o valor nutricional do peixe mandim (Arius spixii)

In an attempt to analyze how processing enhances the nutritional value of the mandim fish (Arius spixii) marketed in Maceio-AL, Brazil, the following nutritional components were determined in fresh and processed (salted-dried) fish: centesimal composition, calorie count, chloride, fatty acid and cholesterol profile. The presence of cholesterol oxides was also investigated. Respective results for fresh and processed mandim fish were: moisture (70.13% and 40.31%), proteins (51.73% and 38.07%, dried), carbohyrdrates (4.67% and 2.24%, dried), calories (486 kcal/100g and 367 kcal/100g, dried), fatty acids (polyunsaturared 14,54% and 15,49%, omega-3 8,51% and 6,51%), cholesterol (82.66 mg/100g and 61.30 mg/100g) and oxides (7-ketocholesterol 8.31 µg/g and 17.90 µg/g). These figures clearly showed that processing led to significant change in the nutritional value of the mandim fish.

Perfil de ácidos graxos, composição centesimal e valor calÓrico de moluscos crus e cozidos com leite de coco da cidade de MaceiÓ-Al

The aim of this study was to assess the profile of fatty acids, the chemical centesimal composition and caloric value of raw and boiled mollusks in the city of Maceio. Three species were analyzed: Mytella falcata, Anomalocardia brasiliana and Tagelus plebeus, known locally as sururu, macunim and unha de velho, respectively. Raw and boiled (with coconut milk) specimens were evaluated. Uncooked mollusks were moist and rich in proteins. The greatest concentration of lipids and ashes was found in sururu and macunim, respectively. Sururu had the highest caloric value. Dry coction resulted in a significant reduction in the amount of protein and in a marked increase in the levels of lipids and ashes in mollusks. The highest caloric value was seen in boiled Tagelus plebeus. The predominant polyunsaturated fatty acids in all the raw samples were docosahexaenoic and eicosapentaenoic. Linoleic, linolenic, and aArachidonic acids were also detected. After boiling, the levels of the saturated lauric and miristic acids rose significantly, whereas those of stearic acid decreased considerably in all the raw samples. Linoleic acid was notably reduced in unha de velho and macunim. The polyunsaturated linolenic, arachidonic, eicosapentaenoic, and docosahexaenoic acids were markedly reduced in all mollusks.

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

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.

Changes in the lipid fraction of king mackerel pan fried in coconut oil and cooked in coconut milk

The influence of cooking on the nutritional value of king mackerel when cooked in coconut milk or pan fried in coconut oil was verified from the alterations in the fatty acid content; formation of cholesterol oxides and the nutritional quality indices of the lipids. Cooking in coconut milk caused an 11.6% reduction in the protein content and 28.3% reduction in the ash content. The lipid content increased after cooking (253%) and frying (198%) causing an increase in the caloric value. The total saturated and monounsaturated fatty acids of the cooked king mackerel increased 462% and 248%, respectively, whereas these increases were 418% and 130%, respectively, for the fried king mackerel. There were reductions of 21% and 38% in the total EPA+DHA of the pan fried and cooked samples, respectively, as compared to the fresh king mackerel. The heat treatment did not cause alterations in cholesterol content.