title: Sensor fusion for on-line monitoring of yoghurt fermentation.
abstract: Measurement data from an electronic nose (EN), a near-infrared spectrometer (NIRS) and standard bioreactor probes were used to follow the course of lab-scale yoghurt fermentation. The sensor signals were fused using a cascade neural network: a primary network predicted quantitative process variables, including lactose, galactose and lactate; a secondary network predicted a qualitative process state variable describing critical process phases, such as the onset of coagulation or the harvest time. Although the accuracy of the neural network prediction was acceptable and comparable with the off-line reference assay, its stability and performance were significantly improved by correction of faulty data. The results demonstrate that on-line sensor fusion with the chosen analyzers improves monitoring and quality control of yoghurt fermentation with implications to other fermentation processes.
authors.affiliation: Division of Biotechnology, Department of Physics and Measurement Technology, Linköping University, S-58183 Linköping, Sweden.
authors.forename: Christian
authors.initials: C
authors.lastname: Cimander
authors.forename: Maria
authors.initials: M
authors.lastname: Carlsson
authors.forename: Carl-Fredrik
authors.initials: CF
authors.lastname: Mandenius
mesh_terms: D000818:Animals; D001419:Bacteria / Q000378:metabolism; D019149:Bioreactors / Q000382:microbiology*; D002417:Cattle; D003198:Computer Simulation; D004867:Equipment Design; D005246:Feedback; D005285:Fermentation; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D005690:Galactose / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000378:metabolism; D007785:Lactose / Q000378:metabolism; D008892:Milk / Q000378:metabolism / Q000382:microbiology; D008954:Models, Biological; D016571:Neural Networks, Computer; D009812:Odorants / Q000032:analysis; D009862:Online Systems; D011786:Quality Control; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019265:Spectroscopy, Near-Infrared / Q000379:methods; D018511:Systems Integration; D013696:Temperature; D014159:Transducers; D015014:Yogurt / Q000032:analysis* / Q000382:microbiology*
chemical_list: D019344:Lactic Acid; D007785:Lactose; D005690:Galactose