Kefir yeast technology: scale-up in SCP production using milk whey.

A three-step process to scale-up kefir biomass production at a semi-industrial scale employing whey is reported. Aerobic fermentations were initially performed at laboratory scales, in 1.5- and 4-L bioreactors, yielding 79 g/L final kefir biomass (0.89 g/g of lactose utilized), in 7 h of fermentation time. The use of whey as carbon source even in solid cultures led to the formation of a granular biomass. These results encouraged scale-up at a semi-industrial-scale pilot plant employing 100- and 3,000-L bioreactors, leading to the development of a process for granular kefir biomass production. The results validated the laboratory-scale experiments and the avoidance of centrifugal separators due to granular biomass formation. Pilot-plant operations showed kefir to be highly resistant to contamination under actual industrial conditions and no serious problems in handling of raw materials and equipment were observed. Economic analysis showed a 20% higher cost of the market price of products, with added value of up to 15.9 x 10(9) within the European Union.

Development of a novel whey beverage by fermentation with kefir granules. Effect of various treatments.

The development of a novel whey-based beverage with acceptable organoleptic properties is reported, where various treatments were studied. Kefir yeast immobilized on delignified cellulosic materials (DCM) or gluten pellets proved to accelerate whey fermentation significantly, with the latter support being not so preferable. Kefir granules seemed to achieve similar fermentation times as DCM. The final pH of the product is suggested to be 4.1 since the profile of the volatile byproducts was higher than other pH values tested. The addition of fructose seemed to be beneficial on the volatile content of the product, although its acceptability as determined by a preference panel was similar to that of the control. Finally, black raisin extract appeared to promote fermentation without any positive effect on the preference of the evaluators.

Antioxidative properties of water extracts obtained from herbs of the species Lamiaceae.

Essential oils and extracts of aromatic herbs obtained by organic solvents have been extensively studied for their antioxidant activity in lipid substrates. Very little is known about the possible presence of antioxidants in polar extracts from herbs used in preparation of infusions and decoctions. In this work water extracts of six different herbs of the Lamiaceae family (dittany, lemon balm, mint, sage, sideritis and sweet marjoram) were prepared. The extracts were examined for their effect against lipid oxidation in comparison to a tea water extract. Sweet marjoram, sage and dittany extracts were found to have a remarkable capacity in retarding lipid oxidation. Examination by thin-layer chromatography of the freeze-dried extracts, before and after hydrolysis, showed that the extracts were rich in bound forms of phenolic compounds such as hydroxycinnamic acids and flavonoids. Rosmarinic and caffeic acids were detected in all extracts with the exception of those from mint and sideritis. These results indicate that certain plants used for the preparation of infusions could be further studied like tea as sources of antioxidants.