Volatiles formation from grape must fermentation using a cryophilic and thermotolerant yeast.
Grape must fermentation performance and volatiles formation by simultaneously cryophilic and thermotolerant yeast (strain AXAZ-1), isolated from grapes in Greece, was evaluated in a wide temperature range (5-40°C). Yeast strain was immobilized on brewer's spent grains (BSG) and the formed biocatalyst was introduced into a Multi-Stage Fixed Bed Tower (MFBT) bioreactor. Almost complete sugar utilization from the aforementioned biocatalyst was observed in a wide temperature spectrum, ranging from 5 °C to 37 °C, while at 40 °C residual sugar was up to 29 g/l. Time to complete fermentation with the immobilized yeast ranged from 290 h at 5 °C and 120 h at 40 °C to 25 h at 33 °C. The daily ethanol productivity reached maximum (88.6 g/l) and minimum (5.6 g/l) levels at 33 °C and 5 °C, respectively. The aroma-related compounds' profiles of immobilized cells at different fermentation temperatures were evaluated by using solid phase microextraction (SPME) gas chromatography/mass spectrometry (GC/MS). Must fermentation resulted in a high-quality fermentation product due to the low concentrations of higher and amyl alcohols at all temperatures tested. AXAZ-1 is a very promising strain for quality wine production, as it is capable of performing fermentations of high ethanol concentration and productivities in both low and high temperatures.
Food Biotechnology Group, Section of Analytical Environmental and Applied Chemistry, Department of Chemistry, University of Patras, 26500 Patras, Greece. Kopsahelis@upatras.gr
Nikolaos
N
Kopsahelis
Loulouda
L
Bosnea
Maria
M
Kanellaki
Athanasios A
AA
Koutinas
D001628:Beverages / Q000382:microbiology*; D019149:Bioreactors / Q000382:microbiology; D018914:Cells, Immobilized / Q000378:metabolism; D003080:Cold Temperature; D005285:Fermentation; D006358:Hot Temperature; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D027843:Vitis; D055549:Volatile Organic Compounds / Q000378:metabolism*
D055549:Volatile Organic Compounds