Lecture 16 Flashcards
How does edible algae effect the gut microbiota?
research suggests that gene transfer can occur, for example porphyranse genes has been found in gut’s of those who eat a lot of nori
What is the purpose of food fermentation?
preserve food by limiting microbial growth, improve digestibility by breaking down fibres, and add nutrients/flavor
What microbes do traditional fermented food depend on?
indigenous flora (microbes naturally in food) starter cultures (microbes from previous fermentation)
What are the major classes of fermentation reactions?
Homolactic acid, propionic acid, heterolactic acid, ethanolic, and alkaline fermentation
What are the starting points to major chemic conversions in fermented foods?
Carbohydrates and proteins
What are the end products of each class of fermentation reaction?
homolactic - lactic acid heterolactic - lactic acid, ethanol, CO2 ethanolic - Ethanol and CO2 alkaline - ammonia propionic - acetic acid, CO2, water
What is the purpose of acid and alkaline fermentation?
controls the pH to help preserve food
Why are there thousands of flavours?
there are thousands of different combinations of fermentation methods
What type of fermentation do dairy products typically undergo?
lactic acid fermentation
How are cheese curds formed?
through proteolysis and acidification
What contents are adjusted when making cheese?
content of fats and proteins
What occurs when milk undergoes lactic acid fermentation?
casein denatures under acidic conditions and forms bonds with hydrophobic molecules in milk
solidification - curds
liquid - whey
How are soft, unripened cheeses made?
no proteolysis/aging, whey is only partially drained which makes food soft and easily spoiled
How are semi-hard ripened cheeses made?
proteolysis occurs, whey is removed, and is aged for months
How is hard cheese made?
concentrated to a very low water content, aged for sometimes years
