EXAM 4: Fermented Foods Flashcards
What is fermentation?
The conversion of carbohydrates into carbon dioxide, ethanol, lactic acid, acetic acid (and other compounds) by yeast or bacteria
- some fermentation requires the use of mold (ex. Blue cheese)
What are the two common fermentation pathways
Lactic acid producing bacteria
Ethanol producing yeasts
What are the other end products of lactic acid producing bacteria
- Other end products: acetic acid, ethanol, CO2
What is the main pathway of lactic acid producing bacteria
90% sugar substrate is converted to lactic acid
What is the pathway of ethanol producing yeasts
This is how alcohol is produced
What are the food products produced by milk fermentation
Cheese
Yogurt
Buttermilk
Sour cream
What are the foods produced by meat fermentation
Sausages (salami, bologna, cervelat)
Fish (fish sauces and pastes)
What foods are produced by grain fermentation
Yeast breads
Beer and sake
Whiskey
What foods are produced by vegetable fermentation
Cucumbers -> pickles
Olives -> green olives
Cabbage -> sauerkraut
Chinese cabbage -> kimchi
Soybeans -> miso, soy sauce, natto, sufu, tempeh
What foods are produced by fruit fermentation
Grapes -> wine
What are the properties of fermented foods
Preservation
Nutrition
Uniqueness
Products made cant be created without fermentation
What are the nutritional properties of fermented foods
Start from nutritionally rich raw materials
Fermentation may enhance nutritional properties
May allow individuals lacking digestive enzymes to consume food products
May offer additional health benefits
- nutrients, polyphenols, live microorganisms
Functionality is different from original source
- exc cheese different from milk
Dairy: what are some cultured dairy products
Yogurt, buttermilk, kefir
What is yogurt
A fermented milk product with at least 8.5% MSNF and 0.5% acid
Added bacteria
- streptococcus thermophilus
- lactobacillus bulgaricus
Held at warm temperatures and fermented until desired consistency is reached. Then fermentation by bacteria is stopped
Gelation and nonfat dried milk may be added to create firmer texture, acidity or add color
Sweeteners/fruit are added to provide flavor - watch kcals!
What is buttermilk
Skim milk or part-skim milk is treated with bacteria
- lactobacillus Bulgaria’s and streptococcus lactis
Lactose -> lactic acid
As pH decreases, proteins precipitate out making thicker milk
Uses
- adds moisture and tanginess to baked products
- provides acid for leavening agent
What is kefir
Milk is treated with kefir grains or starter cultures
- bacteria and yeast
4 end products that create flavor
- lactic acid, acetic acid, diacetyl, and acetaldehyde
Uses
- beverage
What is vinegar
Starter foods
- grape wine or rice wine
- grains or malt mash
- apple cider
Bacteria used
- acetobacter and gluconobacter are primary ones used
To be called a vinegar it must
- contain 4% acetic acid
- pH between 2 to 3.5
Uses:
- flavoring agent in cooking
- tenderizer of meat, poultry, vegetables
What is kombucha
Black tea based
Symbiotic culture of bacteria and yeast (SCOBY)
- acetic acid, bacteria and ethanol fermenting yeast
4 end-products that create flavor: lactic acid, acetic acid, ethanol and CO2
Uses: beverage
What is pickling
Food is preserved by soaking food in acidic liquid
Process
- cover food with vinegar
- then boil
- seal in a container
- stand at least 3 weeks to allow vinegar to penetrate the food
Natural sugars in foods undergo fermentation with they react with vinegar
Foods that are commonly pickled: cucumbers, beets, cauliflower pieces, green tomatoes, green beans, bell peppers, chilis
What is sauerkraut/kimchi
Fermented cabbage
- saurkraut - European that uses white cabbage and salt bring
- kimchi - Korean that uses several cultivars of cabbage and includes flavorings added to the salt brine
Uses lactic acid bacteria for fermentation
End products that contribute to flavor
- acetic acid, ethanol, mannitol, diacetyl, acetaldehyde
Kimchi nutritional benefits
- vitamin c, b vitamins, calcium, iron, potassium, dietary fiber, antioxidants
