General Characteristics of Enzymes

EFEITO DO TRATAMENTO TÉRMICO SOBRE A ATIVIDADE DE PEROXIDASE (POD) E POLIFENOLOXIDASE (PPO) EM MAÇÃ (Mallus comunis)

“…A peroxidase (POD) tem um aumento em sua solubilidade durante o período de maturação, conseqüentemente um aumento na atividade desta enzima no pós-climatério. A peroxidase e a polifenoloxidase têm sido consideradas as principais enzimas responsáveis pela deterioração da qualidade em muitos frutos congelados [7,20]. Estas enzimas podem participar de um grande número de reações oxidativas e de biodegradação, tais como mudança de cor, degradação da clorofila ou auxinas, oxidação de fenóis, oxidação do ácido indol acético, biossíntese da lignina, e muitos destes fatores também podem ser associados com flavour, cor, textura e qualidade nutricional dos alimentos [5,6,8,9,12,21].…”

The Promise of Enzymes in Therapy of Uremia. II. Theoretical Basis – Enzyme Properties

“…The for mer class comprises microorganisms whose enzymes do not change in quality under varying growth conditions, regardless of the presence or absence of a specific sub strate necessary for the maintenance of life. Only the degree of enzymatic activity can be affected [4][5][6][7]12]. The present review deals with microorganisms equipped with trainable enzymes.…”

“…Crystalline lipase has been pre pared from Aspergillus niger [28] and Penicillinum roqueforti [27], and two lipases are synthesized by Rhizopus sp. [32], The positional specificity varies to such an extent that the lipases have been classified according to this property [12]. Thus, Pseudomonas J'ragi shows a strong specificity for the 1 (or 3) positions of TG, while Staphylococcus aureus produces a lipase capable of hydrolyzing the fatty acids of the TG at all positions [34],…”

“…Microorganisms equipped with trainable enzymes fluc tuate with respect to both their ability to produce 'new' enzymes, and their ability to change the enzyme activity as a result of changes in the presence or absence of specific substrate(s) in their environment [3][4][5][6][7][12][13][14], The syn thesis of a given enzyme is thus enhanced by its substrate entering the cell, which then induces a chain of metabolic events, originally termed 'adaptation' [17], The micro organisms with trainable enzymes emanate from the soil [19][20][21] and sometimes live in a well-fertilized environ ment, sometimes under extremely barren conditions. Therefore, they are prepared to meet the extreme require ments in their ecosystem.…”

Study of aroma formation from lipids of the fruit raw material

“…The study of aroma formation from lipids in vitro is connected with large methodological difficulties; so lipid transformation processes due to thermal, physical or combined effects on the plant raw material are not much discussed in scientific publications. According to the theory of flavor restoration by G.Reed, with the availability of precursors, flavor can be restored in the fruit raw material after heat treatment when interaction conditions are created (Reed G.,1966). The preconditions for the repetitive flavor formation from precursors in fruits after heat treatment have been previously investigated (Dateo G.…”