S. de Diego

Bio: S. de Diego is an academic researcher from University of Burgos. The author has contributed to research in topics: Pectinase. The author has an hindex of 1, co-authored 1 publications receiving 115 citations.

Pectin and Pectinases: Production, Characterization and Industrial Application of Microbial Pectinolytic Enzymes

Abstract: Departamento de Bioquimica e Microbiologia Instituto de Biociencias Universidade Estadual Paulista, UNESP, Avenida 24A, 1515, CEP 13506-900 Rio Claro, SP

The Arrhenius Equation Revisited

Abstract: The Arrhenius equation has been widely used as a model of the temperature effect on the rate of chemical reactions and biological processes in foods. Since the model requires that the rate increase monotonically with temperature, its applicability to enzymatic reactions and microbial growth, which have optimal temperature, is obviously limited. This is also true for microbial inactivation and chemical reactions that only start at an elevated temperature, and for complex processes and reactions that do not follow fixed order kinetics, that is, where the isothermal rate constant, however defined, is a function of both temperature and time. The linearity of the Arrhenius plot, that is, Ln[k(T)] vs. 1/T where T is in °K has been traditionally considered evidence of the model's validity. Consequently, the slope of the plot has been used to calculate the reaction or processes’ “energy of activation,” usually without independent verification. Many experimental and simulated rate constant vs. temperature relation...

Date syrup: Effect of hydrolytic enzymes (pectinase/cellulase) on physico-chemical characteristics, sensory and functional properties

Abstract: This work is a contribution to give value addition to second grade dates (with hard texture) by the production of enzymatically treated syrup with high commercial value. It was observed that the pulp:water at ratio 1:3 treated with 50 U of pectinase and 5 U of cellulase during 120 min at 50 °C gave the highest recovery of total soluble solids (72.37 g of total soluble solids/100 g fresh basis) and the lower turbidity (186.45 NTU) compared with control without enzyme addition (Total soluble solids yields: 66.34 g of total soluble solids/100 g fresh basis and turbidity: 1513 NTU). physico-chemical measurements indicated that carbohydrates were predominant in all date varieties as well as their syrups (∼69.59–83.76 g/100 g dry matter in dates and ∼62.14–74.68 g/100 g fresh weight in syrup). Allig variety was characterised by a high content of reducing sugars content (∼77.91 g/100 g dry matter), contrary to Deglet Nour (∼23.17 g/100 g dry matter) and Kentichi (∼21.3 g/100 g dry matter). The CIE L∗ a∗ b∗ colour values of the enzyme-treated date syrup of Deglet Nour, Allig and Kentichi variety showed lighter colours (L∗ values ranging from 24.16 to 44) than the control without enzyme (L∗ values ranging from 0.545 to 17.2). Hedonic evaluation showed that enzyme-treated date syrup was more appreciated by consumers. Microbiological study showed that date syrups were free from aerobes, moulds, coliforms and enterobacteriaceae and were microbiologically stable during five months storage. Results suggested that enzymatic treatment could be used for production of date syrup with high commercial value