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

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

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

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

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

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

Yeast Nutritional Phases Cell # Time lag log stationary death Brix

Survival Factors  Oxygen  Fatty Acids  Sterols  Nutritional Factors

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

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

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

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

The Nutrients Nutrients Rate of Addition (lb /1000 gal) Diammonium Phosphate (DAP) Thiamine Amino Acids Yeast Hulls No Addition Scott Lab Phosphate Titers Bioferm® Equilibre Bioferm® Xtreme Nutrex

ºBrixpHTA (g/L) NOPA (mg/L) Ammonia (mg/L) YAN (mg/L) Yeast Strain Lalvin M2® Composition of Chardonnay Juice