Kinetics and specificity of Lipozyme-catalysed oil hydrolysis in supercritical CO(2)

Blackcurrant seed oil is rich in linoleic and linolenic acids. Selective enzyme-catalysed oil hydrolysis was studied with aim to obtain different levels of alpha- and/or gamma-linolenic acid in the mixture of liberated fatty acids and in the fraction of di- and monoacylglycerols, making them suitable for special dietary needs. The oil was dissolved in supercritical carbon dioxide flowing through a packed bed reactor (temperature 40 degrees C, pressure 15-28 MPa, and superficial velocity 0.1-0.7 mm s(-1)) with Lipozyme(R), a 1,3-specific lipase from Mucor miehei immobilised on a macroporous ion-exchange resin. The enzyme activity was stable as long as water precipitation in the reactor was prevented. The reaction was found to be controlled by both Michaelis-Menten kinetics and mass transfer. The maximum rate of fatty acids liberation per unit amount of enzyme, 2.6 x 10(-3) mol s(-1) kg(-1), was achieved at the maximum flow velocity and pressure. Compared to oil, the liberated fatty acids contained more alpha-linolenic, palmitic and stearic acids, while di- and monoacylglycerols contained increased levels of gamma-linolenic and stearidonic acids

Three-dimensional longitudinal evaluation of palatal vault changes in growing subjects

Objective: To evaluate palatal vault change in children and to assess the reliability of two palatal parameters in assessing growth modifications. Subjects and Methods: A group of 26 healthy white children aged 5.3 ± 0.3 years (15 boys, 11 girls) were randomly selected. Impressions of the upper dental arches were obtained at baseline and at 12, 18, and 30 months follow-up. Three-dimensional digital images of study casts were obtained using a laser scanning device. Palatal surface area and palatal volume were measured on the digital study casts at each time point. Effect size (ES) coefficients were calculated for both parameters as indices of diagnostic reliability in individual subjects when at least equal to 1.0. Results: Significant increases in palatal surface area and volume were seen over the observation period (P < .001). ES coefficients for palatal surface area were greater than those for palatal volume. However, even for the former parameter, only the value taken at 30 months was above the threshold. Conclusions: Growth of the palatal vault was significant during the observation period, which coincides with primary and mixed dentition stages. Palatal surface area appears to be more reliable than palatal volume in assessment of growth modifications in individual subjects