Relationship between Some Characteristics of WPC Hydrolysates and the Enzyme Complement in Commercially Available Proteinase Preparations

Action of a pancreatin and an Aspergillus oryzae protease on whey proteins: correlation among the methods of analysis of the enzymatic hydrolysates

“…Only one report was found in the literature addressing the evaluation of the DH of WPC hydrolysates obtained by an A. oryzae protease. In contrast to the current work, Smyth and FitzGerald (1998), using different hydrolytic conditions (pH 8, 37 ºC, E:S ratio 1:50), found a significant variation between the DH obtained after 30 min (7.1%) and that was obtained after 8 h (24.3%) of reaction using the OPA method. Table 1 shows the occurrence of a positive and significant correlation of strong intensity in three cases for pancreatin (formaldehyde with OPA, formaldehyde with osmometry and OPA with osmometry) and in only one case for the A. oryzae protease (OPA with soluble protein content), according to the values established by Sampaio (2002), i.e., r > 0.7 and p < 0.05.…”

“…Other authors have also used the OPA method for evaluating the DH of WPC proteins hydrolyzed by pancreatin. Using different hydrolytic conditions of the present study (pH 8, 37 °C, E:S 1:50, reaction time of 8:30 h), Smyth and FitzGerald (1998) have reported a maximum DH of 11.5%, which is lower than the values obtained in the current work (21.33 to 22.48%). The higher results obtained here could be explained by the addition of 2-mercaptoethanol.…”

“…2). As the A. oryzae protease (Flavourzyme TM ) has endo-and exopeptidase activities, its action might have released considerable amounts of soluble small peptides, which would have reduced the FolinCiocalteau reagent (Zaia et al 1998) (Smyth and FitzGerald 1998;Briczinski and Roberts 2002) as well as its lower activity (0.69 U mL -1 ). Furthermore, the action of the A. oryzae protease might have resulted in less protein breakdown than pancreatin, leading to a reduced amino acid content in the supernatant and, consequently, the inferior degree of hydrolysis measured by this method.…”

“…For the formaldehyde method, the influence of the reaction time on the DH was higher and longer because a significant increase in the DH occurred when the reaction time increased from 1 h (15.14%) to 2 h (22.26%) and from 2 h to 3 h (26.50%). The A. oryzae protease (Flavourzyme TM ) has both endo-and exopeptidase activities, with the latter being more predominant (Smyth and FitzGerald 1998;Briczinski and Roberts 2002). Thus, the gradual increase of the DH measured by formol titration could be related to the gradual release of amino acids, whose pKa values were different when they were in the free form vs. the peptide form.…”

Influência da ação das enzimas alcalase e flavourzyme no grau de hidrólise das proteínas de carne de frango

“…As reações enzimáticas foram conduzidas à temperatura e pH de máxima atividade catalítica de cada enzima de acordo com a literatura. 9,13,14,[20][21][22][23][24][25] O substrato foi homogeneizado em uma solução tampão fosfato 0,2 M e o pH fixado em 7 para a enzima flavourzyme e 7,5 para a enzima alcalase. Pesou-se uma determinada quantidade de carne de frango que correspondeu a uma concentração total de proteína em solução entre 3,3 e 11,7% (m/v).…”