Zbigniew Czarnecki

Bioconversion of grape and chokeberry wine polyphenols during simulated gastrointestinal in vitro digestion.

The primary objective of the present study was to assess the qualitative and quantitative changes of wine polyphenols during in vitro digestion process conducted in a gastrointestinal tract model. Wines selected for these experiments were red grape, white grape and chokeberry wines. Following the stages of in vitro digestion—stomach, small and large intestine—qualitative and quantitative changes particularly in phenolic acids were monitored. Decomposition of resveratrol and chlorogenic acid, secretion of caffeic acid and formation of other derivatives characterized with high antioxidant activity were determined. As a second focus of this work the evaluation of interactions between human fecal microflora (Enterobacteriaceae, Lactobacillus, Enterococcus and Bifidobacterium) and polyphenolic compounds and their derivatives secreted during the digestion were performed.

Water and energy saving bioprocess for bioethanol production from corn grain applying stillage liquid part recirculation

The distillery stillage is a major and arduous byproduct generated during ethanol production in distilleries. The liquid part of this stillage was proved that can be recycled in the ethanol production from corn, without disturbing the fermentation process. The corn seeds were fermented employing the conventional non-pressure method for gelatinizing as well as including a novelty: Recirculation system of distillery stillage liquid part instead of process water. The efficiency of fermentation and main chemical parameters of stillage were estimated. The liquid part of stillage was recycled 28 times. At these conditions distillery yeast Saccharomyces cerevisiae efficiently produced ethanol yielding 79.80% of the theoretical, keeping the vitality and quantity on the same level. However, recirculation of the liquid part of stillage caused protein and potassium increase in the wet cake what makes this product more attractive for fodder supplementation. It was proven that the addition of stillage liquid fraction to the mashing process instead of process water and 28 recirculation cycles in ethanol production from corn constitutes the way which could significantly reduce the water and energy consumption, what essentially reduce whole general production costs without ethanol efficiency decreasing.