A História da Alimentação: balizas historiográficas

Os M. pretenderam traçar um quadro da História da Alimentação, não como um novo ramo epistemológico da disciplina, mas como um campo em desenvolvimento de práticas e atividades especializadas, incluindo pesquisa, formação, publicações, associações, encontros acadêmicos, etc. Um breve relato das condições em que tal campo se assentou faz-se preceder de um panorama dos estudos de alimentação e temas correia tos, em geral, segundo cinco abardagens Ia biológica, a econômica, a social, a cultural e a filosófica!, assim como da identificação das contribuições mais relevantes da Antropologia, Arqueologia, Sociologia e Geografia. A fim de comentar a multiforme e volumosa bibliografia histórica, foi ela organizada segundo critérios morfológicos. A seguir, alguns tópicos importantes mereceram tratamento à parte: a fome, o alimento e o domínio religioso, as descobertas européias e a difusão mundial de alimentos, gosto e gastronomia. O artigo se encerra com um rápido balanço crítico da historiografia brasileira sobre o tema

Preparation of extracts of culture liquids for gas-chromatographic determination of acidic fermentation products

An extraction method coupled with gas-chromatographic analysis has been devised for the determination of small amounts of C1-C7 branched and straight-chain saturated fatty acids as well as 18 mono-, di- and tricarboxylic acids and related compounds, the latter being analyzed either as their methylesters or as their trimethylsilyl-derivatives. Methods for extracting non-volatile acids or both volatile and non-volatile acids are described for large and small volumes of culture media. The proposed methods have been successfully applied to the determination of non-acidic fermentation products, known amounts of alcohols, and to volatile and non-volatile acids in bacterial fermentation solutions, namely a batch culture of Lactobacillus casei subsp. rhamnosus ATCC 7469. A carbon balance sheet of this organism's metabolic behaviour throughout growth is proposed

Comparative studies of fructose 1,6-diphosphate aldolase from Escherichia coli 518 and Lactobacillus casei var. rhamnosus ATCC 7469

A comparative study has been carried out with FDP aldolases from Escherichia coli 518 and Lactobacillus casei ATCC 7469, which had been purified 17.6- and 65-fold, respectively. The aldolase of L.casei was stable only in the presence of mercaptoethanol, whereas that of E.coli was strongly inhibited at low (1.0×10-4m) and activated at high concentrations (2.0×10-1m) of the same compound. p-Chloromercuric benzoic acid inhibited both aldolases, with 40% inhibition at 2×10-5m with E.coli aldolase against at 2×10-4m with L.casei aldolase. Significant differences were also observed in pH optima and Km values. E.coli aldolase exhibited a maximal activity at pH 9.0 and gave a Km value of 1.76×10-3m FDP with strong substrate inhibition above 7×10-3m, against pH 6.8-7.0 and a Km of 7.04×10-3m FDP for L.casei aldolase. Strong resistance of L.casei aldolase against inhibition by EDTA, Ca2+ and Mn2+ was observed compared with complete inhibition at concentrations of 20 mm, 40 mm and 20 mm, respectively, with E. coli aldolase. Polyacrylamide gel electrophoresis did not reveal any differences between the two enzyme preparations. The differences of the properties of FDP aldolases from different bacterial genera are discussed in relation to other Class II aldolases

The effect of oxygen and pH on the glucose metabolism of Lactobacillus casei var. rhamnosus ATCC 7469

Growth of cultures of Lactobacillus casei ATCC 7469 without pH control under aerobic conditions resulted in very low maximum specific growth rates (0.19 hr-1), exponential glucose utilization rates (0.10 log units/hr/ml of culture) and exponential lactate production rates (0.17 log units/hr/ml of culture), compared to anaerobic cultures. In anaerobic cultures glucose was converted stoichiometrically to lactate but in aerobic cultures this was never observed. It was found that aeration affects both the rate at which glucose is converted to lactate and the stoichiometry of this conversion. The investigation of a number of glucose-metabolizing enzymes suggests that an oxidative pathway for glucose breakdown becomes operative under aerated conditions