New Coproduct Technology Produces Food-Grade Yeast

by Don McLellan (AFC Yeast/Ethanol Producer Magazine) Typically, in ethanol production the nonfermentable leftovers from the feedstocks and yeast are combined and sold either as wetcake or dried distillers grains for feed. But the yeast included in that sale of animal feed includes protein, sometimes vitamins and minerals, cell walls and nucleotides, which have a value in their own right on world markets.

So the questions are: 1. How can those components be collected separately without losing them in the mix? 2. Isn’t there some way that ethanol producers can earn some additional revenue from these components?

When the ethanol fermentation process is finished, the yeast cells, still intact and maintaining their full integrity, can be centrifuged off from the beer prior to distillation.

The separated, washed and dried yeast has a protein content between 45 and 55 percent, is rich in B vitamins and minerals and contains 7 percent ash. It also contains beta glucans and mannans that have medical applications along with the potent antioxidant glutathione and traces of other elements. As a vegetable yeast, it is suitable for vegans and vegetarians and has GRAS status (generally regarded as safe under the U.S. Food and Drug Administration.)

• An egg substitute in baked goods such as cakes, biscuits, muffins or donuts that retains the protein content previously provided by eggs.

• A milk extender that can increase milk volume by 30 percent, without settling due to the yeast’s functional property of solubility. This would have particular relevance for feeding young animals because of the presence of nucleotides.

• A protein concentrate for use in sports and health drinks or in a range of textured vegetable protein dishes intended as meat substitutes.

The research findings have potential to be attractive to the ethanol producer economically. Because the ethanol fermentation period is so short, it may be possible to have a second fermentation in the same original time, increasing capacity by 67 to 100 percent. READ MORE