Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Utilization of fruit and vegetable pomace and biowaste

The value of various agro-food processing wastes can be increased through fermentation. At present large amounts of vegetable wastes (pomace) are generated during juice extraction from fruit and vegetables. These are often dumped in landfills or fed to animals. The organic fraction of municipal waste (here termed biowaste) may have a similar composition to pomace and may also be upgraded in this way. The project considers a number of different wastes (carrot, potato, grape) and a number of products (dietary fibre, enzymes, waste water processing additive, colours and flavours). The main conversion process used for upgrading under investigation is bacterial fermentation using either lactobacilli or bacilli.

Conversion of vegetable residues to a dietary fibre food additive was investigated using lactic acid fermentation. The possibility of using potato waste as a substrate for the production of microbial amylase and technical grade lactic acid was established. Grape waste has been investigated as a source of wine pip oil, colourings and grape flavour. It has been shown that these processes can be enhanced by incorporating enzymic treatment steps. Good lactic acid fermentation of carrot pomace was observed, using a lactobacillus isolated from sour dough at ambient temperatures in stainless steel vessels. In studies of grape pomace fermentation there was found to be a progressive, temperature inactivation of both yeasts and lactic acid bacteria, leading to the selection of a number of resistant strains. The use of carrot pomace in water treatment focused on active and dense granular sludge in upflow anaerobic sludge blanket (UASB) reactors. The best results were obtained when fresh carrot pulp was added to the lab scale UASB reactors in an integrated recycle contact chamber. This was tried out on a real industrial waste water and was shown to be successful. Finally, enzyme production on potato waste has yielded two alpha-amylases from Bacillus stearothermophilus.

Reported by

Rheinische Friedrich-Wilhelms-Universität Bonn
Römerstraße 164
53117 Bonn
Germany
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