Impact of Nutrients on Saccharomyces Aroma Compounds

1. Impact of Nutrients on Saccharomyces Aroma Compounds Linda F. Bisson Department of Viticulture and Enology University of California, Davis

2. Yeast Nutrition • Macronutrients: Building blocks needed for new cell material • Micronutrients: Catalysts needed to facilitate biochemical reactions

3. Macronutrients • Carbon/Energy Sources: glucose, fructose, sucrose • Nitrogen Sources: amino acids, ammonia, nucleotide bases, peptides • Phosphate Sources: inorganic phosphate, organic phosphate compounds • Sulfur Sources: inorganic sulfate, organic sulfur compounds

4. Micronutrients • Minerals and Trace Elements: Mg, Ca, Mn, K, Zn, Fe, Cu • Vitamins: biotin is the only required vitamin, but others are stimulatory

5. Nutrients Are Required For: • Creation of new cells • Maintenance of metabolism • Adaptation to new environments • Stress tolerance

6. Nutritional Requirements of Different Phases of Fermentation • Growth Phase: Building blocks and catalysts • Stationary Phase: Survival factors

7. Yeast Nutritional Phases stationary death Cell # log Brix lag Time

8. Survival Factors • Oxygen • Fatty Acids • Sterols • Nutritional Factors

9. Nutrition and Aroma • Allow fed species to proliferate and dominate • Affects persistence in environment and prevention of spoilage • Directs end product formation • Affects enzymatic activities

10. Macronutrients and Aroma • Sugars: give rise to ethanol, organic acids, fatty acids • Nitrogen compounds: give rise to esters, fusel alcohols and aldehydes • Sulfur compounds: give rise to S-volatiles

11. Micronutrients and Aroma • Impacts enzymatic portfolio • Limitation can impact cell growth and metabolism • Can be degraded if in excess to aromatic compounds

12. Nutrient Additions Tasting • Glass 1: No addition • Glass 2: Phosphate titers • Glass 3: Bioferm Equilibre • Glass 4: Bioferm Xtreme: one addition • Glass 5: Bioferm Xtreme: split addition • Glass 6: Nutrex 370

13. The Nutrients

15. Composition of Chardonnay Juice