Effect of continuous/discontinuous vacuum distillation during fermentation on the volatiles and sensory profiles of unfiltered and unpasteurized Low Alcoholic Beers (LAB)

Title : Effect of continuous/discontinuous vacuum distillation during fermentation on the volatiles and sensory profiles of unfiltered and unpasteurized Low Alcoholic Beers (LAB)

Abstract:

Low-alcoholic beer (LAB) and Non-alcoholic beer (NAB) have gained market share and show increasing sales. A pilot scale under-vacuum fermenter/distiller was used to produce unfiltered and unpasteurized LAB, with a high-temperature fermenting yeast to allow under-vacuum alcohol distillation at 40 °C and negative pressure of 0.8 bar. The tests were carried out in 9 hours, on continuous and discontinuous fermentation/distillation processes starting at 5 hours post yeast inoculum, evaluating volatile composition and alcohol content at different stages. To improve the LAB aroma and flavor profile after the loss of volatiles in distillation, the green beer was subjected to cold maturation (4 °C) and flavored with an LAB-specific hop-derived flavoring product. A trained panel test tasted the LAB for the sensorial evaluation. The results show significant differences among the “green beer” obtained with continuous and discontinuous tests. At the end of fermentation/distillation the alcohol content was lower for the continuous tests while for discontinuous ones the volatiles profile showed higher levels of aldehydes and vicinal diketones. The levels of higher alcohol were similar among the samples. After the cold maturation and aromatization, the beer's volatile profiles were obtained for aldehydes, vicinal diketones, higher alcohols, esters, and hop-derived aromatic compounds. An aromatic strong hop character characterized the beers probably because of the reduced masking effect due to the removal of the other volatiles during distillation. Further research will be needed to investigate LAB stability during storage. This research project was carried out with the financial support of the National Recovery and Resilience Plan (NRRP), Research projects of national interest (PRIN) 2022, funded by the European Union – NextGenerationEU, Cod. Prog.: P2022JEFNF CUP: J53D23018340001.

Biography:

Alfeo studied agriculture, food, and forest sciences at the Palermo University, Bulgaria and graduated as MS in 2013. He then joined the research group of Prof. Aldo Todaro at the Food science and technologies lab, of the University of Palermo, Italy. In 2018, he received his Ph.D. in food science and technology at the same institution. After six months of postdoctoral fellowship supervised by Prof. Rosa Palmeri at the University of Catania, Italy, he joined the research group of Prof. Ombretta Marconi at the Italian Brewing Research Centre, University of Perugia. He has published 18 research articles in SCI(E) journals.