Statistical analysis in enrichment of total whey protein by continuous foam fractionation method

The objective of the present study was to optimize the operating conditions in the separation of the total whey proteins from whey by continuous foam fractionation method using response surface methodology (RSM). The effects of the different process variables such as pH (X1) of proteins in feed, gas flow rate, (X2) of initial feed solution, protein: surfactant ratio (X3) and volumetric flow rate (X4) where investigated on the performance criteria of fractionation of raw processed whey. Four factors, three levels Box-Behnken design was used for the optimization procedure. Quadratic model regression equations and response surface plots correlate independent variables (X1, X2, X3 and X4) and dependent variables (response) such as concentration of Foamate (Cf), Enrichment ratio (Er), and percentage Recovery (% Rp) of total whey proteins. All the four factors had significant effects on the response variables. The model predicted that the optimized values of the factors (X1, X2, X3 and X4) such as 5, 290, 1.5 and 14, respectively. The predicted responses were (concentration of foamate, enrichment ratio, and percentage recovery) such as 6647.32, 13.27, and 78.02, respectively. Experiments were performed with the predicted values of factors

Nematic Films and Radially Anisotropic Delaunay Surfaces

We develop a theory of axisymmetric surfaces minimizing a combination of surface tension and nematic elastic energies which may be suitable for describing simple film and bubble shapes. As a function of the elastic constant and the applied tension on the bubbles, we find the analogues of the unduloid, sphere, and nodoid in addition to other new surfaces.Comment: 15 pages, 18 figure

Maintaining yeast viability in continuous primary beer fermentation

Continuous fermentation is a long known and vastly studied process. The use of immobilized cell technology (ICT) is exploited in a significant number of studies owing to the associated high volumetric productivity, time savings and low capital demand. This work was aimed at solving one of the most relevant obstacles to implementing ICT on a large scale in beer fermentations, namely the control of biomass and the maintenance of cell viability in a gas-lift bioreactor. For this purpose, foam fractionation by skimming was proposed as a tool for control of continuous biomass concentration. The consequences of foaming on lignocellulosic yeast carrier losses were assessed and discussed. A steady consumption of sugars from wort, as well as consistent ethanol production, were achieved. The viability of the suspended cells in the reactor was compared with that of the cell population in the foam using flow cytometry. Results suggest that foam might be used as a promising tool to skim non-viable biomass out of the gas-lift reactor, thus ensuring the maintenance of a cell culture with optimum viability. Copyright © 2014 The Institute of Brewing & DistillingEduardo Pires gratefully acknowledges the Fundacao para a Ciencia e a Tecnologia (FCT, Portugal) for PhD fellowship support (SFRH/BD/61777/2009) and Cristina Ribeiro from the Centre of Molecular and Environmental Biology/Department of Biology for technical support. This work was also supported by FEDER through POFC - COMPETE and by national funds from FCT through the project PEst-C/BIA/UI4050/2011. The materials supplied by UNICER Bebidas, S.A. (S. Mamede de Infesta, Portugal) are gratefully acknowledged. The financial contributions of the EU FP7 project EcoBioCAP - Ecoefficient Biodegradable Composite Advanced Packaging, grant agreement no. 265669 as well as of the Grant Agency of the Czech Republic (project GACR P503/12/1424) are also gratefully acknowledged