Critical moisture content for microbial growth in dried food-processing residues.
BACKGROUND
Food-processing residues are good feedstocks for biofuel and biochemical production because they have high energy content and are abundant. Year-round biofuel and biochemical production requires proper storage to prevent microbial decomposition and thermal runaway. In this study, microbial activity of tomato pomace (TP), grape pomace (GP), fermented grape pomace (FGP) and sugar beet pulp (SBP) was monitored at nine different moisture contents.


RESULTS
Maximum and cumulative respirations for each feedstock with respect to moisture content followed a sigmoidal relationship. The critical moisture content below which no microbial activity was detected for SBP, TP, FGP and GP was 24-31, 16-21, 23-33 and 43-46% (dry basis) respectively. A logarithmic relationship was observed (R(2) = 0.94) between critical moisture content and initial water-soluble carbohydrate (WSC) content of the processing residues.


CONCLUSIONS
The critical moisture content below which no microbial activity was detected and the relationship between critical moisture content and initial WSC content were determined in this study for four food-processing residues. Both parameters permit evaluation of the potential for deterioration of food-processing residues during storage based on moisture content and WSC content.
Rezaei
Farzaneh
F
Department of Biological and Agricultural Engineering, University of California at Davis, Davis, CA 95616 , USA.
Vandergheynst
Jean S
JS
D027461:Beta vulgaris / Q000382:microbiology; D056804:Biofuels; D002241:Carbohydrates / Q000032:analysis*; D019069:Cell Respiration; D003890:Desiccation; D005285:Fermentation; D005511:Food Handling; D005516:Food Microbiology; D005638:Fruit / Q000382:microbiology; D007218:Industrial Microbiology; D018551:Solanum lycopersicum / Q000382:microbiology; D019684:Magnoliopsida / Q000382:microbiology*; D008827:Microbiological Phenomena; D028321:Plant Preparations / Q000737:chemistry*; D018517:Plant Roots / Q000382:microbiology; D012016:Reference Values; D027843:Vitis / Q000382:microbiology; D014867:Water / Q000032:analysis*
D056804:Biofuels; D002241:Carbohydrates; D028321:Plant Preparations; D014867:Water