Brewing with Sea Vegetable: The Effect of Spirulina (Arthrospira platensis) Supplementation on Brewing Fermentation Kinetics, Yeast Behavior, and the Physiochemical Properties of the Product

Spirulina is a highly nutritious microalgae commonly used as a food additive. During fermentation, different adjuncts are incorporated to act as a nutrient source for yeast and fortify or modify the sensory attributes of the final product. In this study, the effect of Spirulina on the characteristics of controlled yeast fermentation and the production of volatile organic compounds (VOCs) was analyzed. Spirulina was added to malted barley during mashing and fermented under standard conditions. An unaltered mash (negative control) and yeast extract (positive control) were also fermented. The addition of Spirulina resulted in an increased fermentation rate (~14% faster) and bigger yeast cells (~34% larger) in comparison to the negative control. There were differences in color (determined as SRM) between treatments; however, there were only minor differences in VOCs, with no statistical differences observed between chemical compound groups. No differences were observed in the pH, total number of yeast cells, or final attenuation between treatments. The primary mechanism for the observed differences is believed to be an increase in amino acids available to yeast that were contributed by the Spirulina. This shows both that Spirulina has a high potential as a fermentation adjunct and that the amino acid profile of an adjunct can significantly impact fermentation.