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doi:10.1016/j.jbiotec.2010.09.352

[P-F.109]

Technical and economic prefeasibility of a fructooligosaccha-rides production plant by enzymatic transformation of thicksugar beet juice

Gonzalo Correa 1, Carolina Silva 1, Paola Poirrier 1,2,∗, María ElviraZúniga 1,2

1 Pontificia Universidad Católica de Valparaíso, Chile2 CREAS, ChileKeywords: Fructooligosaccharides; Enzymatic transformation;Thick sugar beet juice

Introduction: Fructoligosaccharides (FOS) are food additiveswith several health benefits, especially in the digestive tube, wherethey perform as prebiotics with several advantages over otheroligosaccharides synthesized industrially.

This work studies the pre-feasibility and design of a plant forscale production of FOS from a by-products or products from thesugar beet production process using enzymatic transformation.

Process outline: FOS production consisted of a conditioning stageof the raw material followed by enzymatic synthesis. The enzymaticreaction was carried out using a commercial enzyme preparationwith elevated fructosiltransferase activity, at pH 5.5 and 60 ◦C for24 h until a mixture of short-chain FOS of DP <5 such as 1-kestose,nistose and fructosilnistose was obtained. Finally the product wasconcentrated through a triple-effect evaporator spray-dried result-ing in a powder rich in FOS.Economic Evaluation: It was determinedfrom market research an annual processing capacity of 16.000 tonsof sugar thick juice to generate an annual output of 4.800 tons ofFOS, with an estimated lifespan of the project of 10 years.Economicassessment indicated positive values of profitability, assuming aprice for the product of U.S. $ 4.1 per kilogram with an estimatedpayback period of one year.

Conclusions: FOS production from sugar beet thick juice productsand by-products constitute an innovative and profitable alternativethat could support the sugar beet industry in Chile, while satisfy-ing the growing needs of the population for healthy foods withbioactive compounds.

Acknowledgements

PUCV ProJect BIOACTIVES, creas.

doi:10.1016/j.jbiotec.2010.09.353

[P-F.110]

Thermal sanitising in a commercial dishwashing machine

C. Nicolella 1,∗, B. Casini 1, F. Rossi 2, A. Chericoni 3, G. Pardini 3

1 University of Pisa, Italy2 Polo Tecnologico Magona, Italy3 Eurotec Warewashing, ItalyKeywords: E.coli; thermal inactivation; bacterial count

Unsanitised food contact surfaces can be a direct or indirectsource of food borne illness, as pathogens can be transferred tofood from crockery and utensils that are not properly sanitised.Several national and international standards establish minimumpublic health and sanitising requirements for the materials, design,construction and performance of commercial and household ware-washing machines. The improvement of sanitising of food contactsurfaces was recommended by the US Department of Health andHuman Services in a report on the occurrence of food borne illnessrisk factors in hospital, schools and restaurants. Improper clean-ing and sanitising of food contact surfaces was the factor mostcommonly observed to be out of compliance.

In this work, the reduction of microbial counts in a commer-cial dishwashing machine is experimentally investigated, with themain aim of establishing the relationship between operating con-ditions (namely duration and temperature of the rinsing phase)and sanitising performance. The experimental results obtained on apilot dishwashing machine are analysed using available kinetic datafor reference organisms, and the compatibility of the observed sani-tising performance with quality standards is discussed. The kineticanalysis suggests that the thermal effect is not sufficient to obtainsignificant reductions of microbial counts on food contact surfacesunder typical conditions of temperature and washing cycle length.The observed reduction of microbial counts increases with the vol-ume of water used for rinsing. It is inferred from these experimentalresults that the reduction of microbial counts on food contact sur-faces is mainly due to the mechanical elution of water jets ratherthan to thermal inactivation.

doi:10.1016/j.jbiotec.2010.09.354

[P-F.111]

Mixing regimes and washout conditions for continuous culturesin a three-stage tubular model of the human gut

C. Nicolella

University of Pisa, ItalyKeywords: mixing; washout; colon

The development and performance of a three-stage tubu-lar model of the large human intestine is outlined. Each stagecomprises a membrane fermenter where flow of an aqueouspolyethylene glycol solution on the outside of the tubular mem-brane is used to control the removal of water and metabolites(principally short chain fatty acids) from, and thus the pH of, theflowing contents on the fermenter side. The three stage system gavea fair representation of conditions in the human gut. Numbers ofthe main bacterial groups were consistently higher than in an exist-ing three-chemostat gut model system, suggesting the advantagesof the new design in providing an environment for bacterial growthto represent the actual colonic microflora. Concentrations of shortchain fatty acids and pH levels throughout the system were simi-lar to those associated with corresponding sections of the humancolon. The model was able to achieve considerable water transfer