Effects of the Addition of Dendrobium officinale on Beer Yeast Fermentation

Dendrobium officinale is a precious Chinese medicinal plant that is rich in polysaccharides, flavonoids, polyphenols, and other bioactive ingredients, and has a variety of biological activities. To explore the effects of D. officinale on the growth and metabolism of Saccharomyces cerevisiae, different concentrations (0, 10, 30, 50, and 100 g/L) of fresh D. officinale were added to the wort during the fermentation. The amount of yeast, alcohol content, reducing sugars, total acidity, pH, CO2 loss, and foam height were analyzed. Meanwhile, the glucose uptake, cell viability, key enzyme activity of yeast, total phenolics, antioxidant activity, volatile compounds, and consumer acceptance of brewed samples were also analyzed. The results showed that the growth and metabolism of yeast could be promoted by a suitable dosage of D. officinale but were inhibited at high dosage (100 g/L). The addition of D. officinale increased the activities of glucose-6-phosphate dehydrogenase and alcohol dehydrogenase, while the highest concentration of D. officinale (100 g/L) decreased the glucose uptake and cell activity of the yeast. The contents of total phenolics and esters, along with the scavenging activity against ABTS radicals, were increased, indicating that the antioxidant activity and aromatic characteristics of beer would be improved by the addition of D. officinale.