In conclusion, the samples with phenolic extracts showed a better stability in terms of turbidity, colour formation and foam quality.
The use of all studied phenolic extracts showed an enhancement of flavour stability and a protective effect on beer quality. The best results were obtained with the condensed tannins and in particular with the extract Oxnomore super (a high purity green tea extract).
Specifically, data analysis revealed beer with Oxnomore super as the most stable, limiting the increase in colour and turbidity and the loss of foam. Moreover, the panellists judged the beer added with Oxnomore super to be the most elegant for aroma and taste, with a smooth and rounded body. Further, Oxnomore super showed an interesting antioxidant activity: excellent inhibition of free radicals (DPPH), good reducing capacity against the Fe3+ ion (FRAP), and above all exhibited excellent oxygen scavenger action (ABTS) as demonstrated also by the substantial reduction of the dissolved oxygen.
Also, Oxnomore pro recorded relevant antioxidant power and excellent quality and analytical values, but especially improved the overall organoleptic beer profile. Grape seed tannins increased the citric and spicy notes, but above all increased the body of the beer, defined by the judges as more rounded.
This study confirms that the condensed phenolic extracts are a possible solution to counteract the effects of beer aging. According to our results, it is important to test the phenolic extracts before marketing them and then adding beer. This work makes it clear how each tannin can bring different characteristics to beer especially from the organoleptic point of view. Cooperation between universities and companies remains a fundamental aspect.