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Valencia P.L.,Federico Santa Maria Technical University | Flores S.A.,Federico Santa Maria Technical University | Pinto M.J.,Federico Santa Maria Technical University | Almonacid S.F.,Federico Santa Maria Technical University | Almonacid S.F.,Centro Regional Of Estudios En Alimentos Y Salud Creas
Journal of Food Engineering | Year: 2016

The aim of this work was to validate a mathematical model and evaluate hydrolysis of salmon muscle proteins by Alcalase in batch reactor. The inhibition constants were correlated with conversion and temperature thus improving dramatically the agreement between model predictions and experimental hydrolysis time courses. The standard operation in batch reactor consisting in pre-heating, isothermal stage and inactivation of enzyme was evaluated through simulation of different operational strategies based on increasing temperature gradients. Operational conditions were 7.5%(w/w) protein, 1 g/l Alcalase and different temperatures from 50 °C to 73 °C. The optimal temperature for the standard process was 68 °C with a processing time of 41 min. Different operational strategies, included temperature profiles, resulted in longer operation times. The standard process was the best reactor performance due to the maximization of the enzyme efficiency. © 2015 Elsevier Ltd. Source


Valencia P.,Federico Santa Maria Technical University | Espinoza K.,Federico Santa Maria Technical University | Ceballos A.,Federico Santa Maria Technical University | Pinto M.,Federico Santa Maria Technical University | And 2 more authors.
Process Biochemistry | Year: 2015

A novel methodology for the modeling and characterization of the enzymatic hydrolysis of proteins is proposed. The hydrolysis time course can be predicted at different operating conditions for protein concentration, enzyme concentration and temperature. The hydrolysis kinetics of salmon muscle proteins and whey protein isolate by Alcalase were studied using a central composite design. A combination of the logarithmic equation P = 1/bln (abt + 1) to model the hydrolysis time course with the response surface methodology to correlate the kinetic constants a and b with the operating conditions: protein concentration, enzyme concentration and temperature were achieved. The logarithmic equation was a very good fit with the hydrolysis time courses, with both substrates achieving R2 > 0.995. The kinetic constants a and b were significantly affected by the operating conditions. Empirical models were obtained for a and b as functions of operating conditions. The kinetic constant values were predicted, and a strong correlation between predicted and experimental values was obtained for a (R2 = 0.949) and b (R2 = 0.945). The predicted and experimental time courses resulted in good correlation for both salmon muscle proteins (R2 > 0.987) and whey protein isolate (R2 > 0.978). The model allowed calculation of the hydrolysis time course of proteins from a given set of operating conditions with good predictability. This methodology can be used with different sources of proteins and enzymes to test the susceptibility of proteins to hydrolysis as well as the catalytic efficiency of proteases. Additionally, the combined model can be used as a design and optimization function. © 2015 Elsevier Ltd. All rights reserved. Source


Molinari A.,Pontifical Catholic University of Valparaiso | Oliva A.,Pontifical Catholic University of Valparaiso | Arismendi-Macuer M.,Pontifical Catholic University of Valparaiso | Guzman L.,Pontifical Catholic University of Valparaiso | And 5 more authors.
Molecules | Year: 2015

1H-Benzo[f]indazole-4,9-dione derivatives conjugated with C-protected amino acids (glycine, L-alanine, L-phenylalanine and L-glutamic acid) 6a-l were prepared by chemically modifying the prenyl substituent of 3-methyl-7-(4-methylpent-3-enyl)-1H-benzo[f]indazole-4,9- dione 2 through epoxidation, degradative oxidation, oxidation and N-acyl condensation reactions. The chemical structures of the synthesized compounds were elucidated by analyzing their IR, 1H-NMR and 13C-NMR spectral data together with elemental analysis for carbon, hydrogen and nitrogen. The preliminary in vitro antiproliferative activity of the synthesized derivatives was evaluated on KATO-III and MCF-7 cell lines using a cell proliferation assay. The majority of the derivatives exhibited significant antiproliferative activity with IC50 values ranging from 25.5 to 432.5 μM. These results suggest that 1H-benzo[f]indazole-4,9-dione derivatives are promising molecules to be researched for developing new anticancer agents. © 2015 by The Authors. Source


Vinet R.,University of Valparaiso | Vinet R.,Centro Regional Of Estudios En Alimentos Y Salud Creas | Alvarez R.,University of Valparaiso | Knox M.,University of Valparaiso | And 3 more authors.
Boletin Latinoamericano y del Caribe de Plantas Medicinales y Aromaticas | Year: 2016

Solatium crispum Ruiz & Pav. (S. crispum) is a southern South American native plant that is usually used in traditional medicine for the treatment of symptoms associated with both, acute and chronic ailments. Enema and infusion of leaves and stems are used to treat fever, headache, inflammation and hypertension. In this study, we aim to assess the vasoactive effect of hydroalcoholic extracts of S. crispum on isolated rat aorta rings. The hydroalcoholic extract of S. crispum induced a vasodilatory effect (42.6 ± 4.1%) in aortic rings precontracted with phenylephrine (0.1 μM). The aortic relaxation was largely endothelium-dependent and mediated by nitric oxide (NO). The endothelium- and NO-dependence was demonstrated by a drastic fall in the dilatation induced by the extract when the endothelium was removed (10.6 ± 2.3%) and when nitric oxide synthase (NOS) was inhibited (12.3 ± 2.5%) by nitro-L-arginine (L-NNA). This result supports the popular use of S. crispum in the treatment of hypertension that may be due, at least in part, to the vasodilator effect of one o more compounds present in their leaves and stems. Further studies should be performed to clarify this phenomenon. © 2016. Source


Sotomayor-Zarate R.,University of Valparaiso | Sotomayor-Zarate R.,University of Santiago de Chile | Jara P.,University of Santiago de Chile | Araos P.,Centro Regional Of Estudios En Alimentos Y Salud Creas | And 11 more authors.
Basic and Clinical Pharmacology and Toxicology | Year: 2014

Amphetamine derivatives have therapeutic potential in diseases such as attention deficit hyperactivity disorder, narcolepsy and obesity. However, their prolonged use has been associated with cardiovascular toxicity and addiction. In recent years, we have studied the pharmacological effects of amphetamine derivatives such as methylthioamphetamine (MTA) and N,N-dimethyl-thioamphetamine, with the aim of improving their therapeutic selectivity. In this work, we show that similarly to MTA, N,N-dimethyl-thioamphetamine has effects on the dopamine system, producing a significant increase in extracellular levels of dopamine (as measured by in vivo brain microdialysis) and locomotor activity, which is a behavioural measure of dopaminergic activation. However, unlike MTA, N,N-dimethyl- thioamphetamine does not produce aortic contraction in vitro. Our results show that N,N-dimethyl-thioamphetamine is a drug that retains the dopaminergic effects of amphetamine derivatives but exhibits a lower potential for producing cardiovascular side effectss. © 2013 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society). Source

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