Serendip is an independent site partnering with faculty at multiple colleges and universities around the world. Happy exploring!
Food Microbiology
- Wine
- Sake*
- Beer
- Vinegar
- Cheese
- Soy Sauce
- Sauerkraut
- Yogurt
- Tempeh*
- Oncom
- Quorn
- Kombucha *
Microbial Husbandry (Preferential Selection and Management of Beneficial Micro-Organisms):
- Yeast – Saccharomyces, Brettanomyces, Candida
- Bacteria – Acetobacter, Lactobacillus, Leuconostoc
- Mold – Penicillium, Aspergillus, and Rhizopus
Microbial Husbandry is all about supplying a beneficial energy source (Sugars and Organic Acids) and managing Oxygen, pH, acidity and osmotic balance.
Microbial Husbandry is all about supplying a beneficial energy source (Sugars and Organic Acids) and managing Oxygen, pH, acidity and osmotic balance.
- Description of the Food, Microbes used, and important steps in its production
- Important and/or interesting biochemical transformations facilitated by microbes.
- Brief History and/or Health Claims
- Miscellaneous (only if something seems compelling)
Wine | Sake* |
Beer | Vinegar |
Cheese | Soy Sauce |
Tempeh* | Oncom |
Quorn | Kombucha* |
Yogurt | Sauerkraut |
Winemaking
“…the occurrence of ethanol in ripe and decaying fruit and the substantial heritability of alcoholism in humans suggest an important historical association between primate frugivory and alcohol consumption. “
(from: The Quarterly Review of Biology, 2000).
“Survival and reproductive success hinge on the perception of environmental stimuli. In this regard, foraging efficiency depends on discerning predictive signals in food. A widespread occurrence of ethanol in fruits indicates a sustained historical exposure of frugivores to this compound. Accordingly, Dudley (2000, Quart. Rev. Biol. 75:3–15) proposed that ethanol could represent a prominent sensory cue to primates because of direct and indirectly associated caloric and physiological rewards. …Ethanol has likely played a significant and underestimated role in the regulation of primate foraging behavior.“
(from: INTEGR. COMP. BIOL., 44:295–303 (2004)).
“The ancient chemical evidence now enables the later beverages to be traced back as far as 7000 B.C. and reveals how Chinese beverage-making developed over the millennia. “
(from: PNAS, 2003)
Steps in Wine Making: (Simple Overview), (In the Vineyard) and (Detailed Outline)
- Supplying the Microbes with the "Goods" (Fermentation Substrate and more).
Primary Fermentation:
Secondary Fermentation / Malolactic Fermentation:
- It’s about Apples and Milk (not oranges): Malic Acid versus Lactic Acid
Spoilage / Undesirable Fermentation:
- Metabolic Oxidation of Ethanol by Acetobacter = Vinegar
- Accentuated by chemical oxygenation of Ethanol into Acetaldehyde
Molds found on grapes:
- Aspergillus
- Penicillium
- Rhizopus (Bread, Fruit Mold)
- Botrytis (Noble Rot)* - Necessary for the sweet dessert wines of Sauterne and Monbazillac
Yeast found on grapes:
- Saccharomyces
- Brettanomyces
- Schizosaccharomyces
Good, pleasant, helpful Microbes in Wine:
- Saccharomyces
- Botrytis (Noble Rot)
- Pediococcus cerevisiae, Leuconostoc, Lactobacillus (both in highly controlled conditions)
Bad, unpleasant, unhelpful Microbes in Wine:
- Pediococcus cerevisiae, Leuconostoc, Lactobacillus (in uncontrolled conditions)
- Acetobacter = Vinegar
- Brettanomyces (and basically all yeast other than Saccharomyces cerevisiae) = off flavors
The Good, the Bad and the Ugly – It’s all about aromatic esters and phenols from secondary metabolites:
Examples:
- A condensation between an acetic acid and an alcohol yields the ester ethyl acetate. Small amounts smell and taste fruity, but quickly becomes vinegary and nail polish.
- 4-ethyl phenol formed by Brettanomyces Smell and taste of barnyard, rancidity and sweaty horse.
Comments
Post new comment