1/14/2015
Taints Arising During Malolactic Fermentation
Lucy Joseph Department of Viticulture and Enology U.C. Davis
Malolactic Fermentation
OSBORNE AND EDWARDS, ADVANCES IN FOOD AND NUTRITION RESEARCH VOL 50
1 1/14/2015
Spontaneous ML Fermentation
Lactic Acid Bacteria Found in Wine
• Lactobacillus – Lb. brevis, Lb. casei, Lb. hilgardii, Lb. plantarum, Lb. lindneri, Lb. kunkeei • Pediococcus – Pd. parvulus, Pd. damnosus, Pd. ethanolidurans • Oenococcus – O. oeni • Lactococcus
Oenococcus oeni
Bright Field Phase Contrast
400x
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Oenococcus and Pediococcus
1000x
Lactobacillus brevis 1000x Lactobacillus casei
Lactobacillus kunkeei Lactobacillus delbrueckii
ML Bacteria Sensory Affects
• Buttery or nutty diacetyl • Fruity ester production • Release mono‐terpenes through glucosidase • Acetaldehyde metabolism • Glycerol and erythritol production
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ML Bacteria Sensory Affects
ML Bacteria Sensory Affects
Changes in Aroma/Flavor Compounds
Increase – Fusel alcohols (butanediol, furfuryl alcohol) – Esters (isoamyl acetate, ethyl lactate, 2‐phenethyl acetate) – Fatty acids (isovaleric acid, capric acid, caprylic acid) – Aldehydes and ketones (butanedione, butanone) – Lactones (butyrolactone, pantolactone, furaneol) – Phenols (ethyl and vinyl phenols, eugenol, vanillin) – Terpenes (terpineol, geraniol)
4 1/14/2015
Changes in Aroma/Flavor Compounds
Decrease – Fusel Alcohols (Isoamyl alcohol, butanols, hexanols, phenethyl alcohol) – Esters (ethyl acetate, isoamyl caprylate) – Aldehydes and ketones (ethanal, furfural)
Spoilage Compounds Produced by Lactics
Bacteria Compound Sensory Effect Threshold LAB Acetic Acid Vinegar, pungent, sour 0.2 ppt LAB Ethyl acetate Nail polish remover 7.5 ppm Lb., Oeno. Diacetyl (2,3‐butandione) Butter, nutty, caramel 0.1 to 2 ppm Lb., Pd. 2‐Ethoxy‐3,5‐hexadiene Geranium leaves 0.1 ppb Lb., Oeno. 2‐Acetyl‐ Mousy 4 to 5 ppb tetrahydropyridine Lb., Oeno. 2‐Ethyltetrahydropyridine Mousy 2 to 18 ppb Lb., Oeno. 2‐Acetyl‐1‐pyrroline Mousy 7 to 8 ppb Lb., Pd. Acrolein (+anthocyanin) Bitter Pd. b‐D‐Glucan Ropy, viscous, oily Oeno. Mannitol Viscous, sweet LAB Skatole (indole) Fecal 1.7 ppm (1.8) LAB Biogenic Amines None (headache)
Letters in Applied Microbiology 48 (2009) 149–156 ; E.J. Bartowsky
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Metabolic Pathways
Buttery Aroma
• Chemically 2,3‐butanedione (diacetyl), acetoin, and 2,3‐butanediol • Descriptors – buttery, caramel, nutty, fruity, creamy, cocoa butter, buttermilk, sour cream • Production is controlled by the organism type, the substrate availability, the pH and redox state of the cell
Homo‐ fermentative
Anaerobic Aerobic
6 1/14/2015
Hetero‐ fermentative
Mousy Character
Factors Affecting Mousy Aroma
• Amino acids – ornithine and lysine • Ethanol –other alcohols do not give the same results • Metal ions – Fe+2, Mg+2, Mn+2, Ca+2 (ETHP) • Oxygen
7 1/14/2015
Proposed Pathway
Metabolic Pathways (Indole and Skatole)
Skatole
Metabolic Pathways (Biogenic Amines)
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In Tempranillo Wines
Compound Percent Change Putrescine * 107 Histamine* 114 Tyramine* 175 Cadaverine 8.24 Spermidine* ‐4.82 Agmatine 11.1 Tryptamine 11.3 Phenylethylamine 19.4 Isoamylamine 20.3 Total biogenic amines* 63.4 * Significant
Izquierdo Can ̃as et.al., Journal of Food Composition and Analysis 21 (2008) 731– 735
Is it Brettanomyces or Bacteria?
Aroma/Flavor Brettanomyces Lactic Acid Acetic Acid Bacteria Bacteria Chemical, BandAid X
Smoke, Medicinal X
Earthy, Soy X
Sweat, barnyard X
Mousy, Rancid Corn X X Chips Metallic X X
Artificial Floral X X
Vinegar, Acetic Acid X X X
Nail Polish Remover, X X Ethyl Acetate Butter, diacetyl X
Bitter X X
Animal, Fecal, Fur X
Viscous, Oily, Sweet X
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