The research group of Prof. Bisping deals with fermentations for the production and nutritional improvement (functionality) of food and with fermentations for the processing of food waste. The main research topics are solid substrate fermentations for the enrichment of soybean-based foods with vitamins.
Aerobic and anaerobic submerged fermentations of soya products for enrichment with vitamins, especially vitamin B12, and for the production of naturally formed antibiotic substances, lantibiotics, to improve the shelf life of food are carried out. This research is carried out in a cooperative project in collaboration with the University of Gadjah Mada, Faculty of Agricultural Technology, Yogyakarta, Java, Indonesia.
Another focus is the fermentation of cocoa seeds. It is known that three typical stages occur during cocoa fermentation: 1) alcoholic fermentation, 2) lactic acid fermentation, 3) oxidation of the ethanol formed to acetic acid. It is only when the microbially formed acetic acid penetrates the seed that the conditions for the formation of the cocoa aroma are created. Since cocoa fermentation takes place in the respective countries of cultivation and no starter cultures are used, the composition of the microflora and the population dynamics during fermentation vary. By identifying the composition of the microflora and recording the respective population dynamics, microbiological influencing factors are to be recognised and used to control the cocoa aroma. The flavor is influenced by the fact that not only acetic acid but also microbially formed esters and other short-chain organic compounds that influence the flavor penetrate the cocoa seeds. In this respect, there is an analogy here to the influence of the prevailing microflora on the wine aroma. This research is carried out in cooperation with the Indonesian Institute of Sciences (LIPI), Research Center for Biotechnology, Cibinong, Java and with the Institute for Microbiology and Biochemistry of the Geisenheim University of Applied Sciences, Geisenheim.
A further topic is research into the occurrence of off-flavors in hazelnuts. This project is carried out in cooperation with the Chair of Food Chemistry and Molecular Sensory at the Technical University of Munich in Freising.