Chemical composition of oysters from São Paulo and Paraná, Brazil

Abstract

SYNOPSISDuring the years 1966/ 67 a compara tive study of the chemical composition of oysters was performed on protein, water, ash, trimethylamine oxide, trimethylamine, cru de glycogen, iron (Fe+ + +), calcium, magnesium, total and inorganic ' phosphorus, wÍth oysters coming from the lagoon regions of the State of São Paulo, namely Cananéia and Bertioga Channel (Santos) , and from the State of Paraná.The oyster discussed here is the species found ori mangrove tree stilt roots. It was determined as O~rea arborea Chemnitz, by Dr. Hugo de Souza Lopes, Museu Nacional do Rio de Janeiro. Other zoologists have placed the present species in the genus Crassostrea.Appraisal of the analytical results of the oysters was ma de taking into consideration the reproductive cycle and the meteorological conditions of the three . regions under study.A seasonal variation was observed regarding fat, crude glycogen, dry matter and energy content when related to fresh and dry matter, and of protein when expressed in relation to dry matter.The seasonal variation are related to the r eproductive cycle of Q' ysters and is probably influenced by water temperature variations which depend on the solar radiation incidénce, and aIs o by phytoplankton abundance.W e endeavoured to determine the season when distinct phases of the oyster reproductive cycle occurs, fattening, ripening, gonadal and sexual products discharge, for e;lCh one of the t hree regions studied, as well as the most favorable time of the yéar for comsumption (wint~r and spring). This paper shows that oysters are a complementary source of food and income, that their production must be managed for an optimum return to the population inhalfitingr-the lagoon regions of !>razil southern coast.