Midterm 1 Flashcards
What is a Difference/Discrimination Test?
objective measurement of differences of tastes between similar product types
What are the two sensory tests?
Difference/discrimination test and descriptive test
What is a Descriptive Test?
verbal description of characteristics of products
What is an example of Consumer Testing?
Affective Test
What is an Affective Test?
measurement of a subjective impression or preference for products
Three international food regulatory agencies
FAO, WHO, JECFA
Two theories that are used to describe the chemical basis of sweetness
AH,B, X Theory and the Multi-Point Attachment Theory
AH-B Theory of Sweetness
Proposed that a sweet-tasting compound must contain a hydrogen bond donor (AH), as well as a hydrogen bond acceptor (B)
Multi-point Attachment Theory
Assumes the presence of at least 8 fundamental recognition sites between a sweetener and a sweetness reception site
Which flavours involve the use of ion channels?
Salty and sour tastes are detected through ion channels which regulate the flow of ions across the membrane where the movement generates a voltage
Which flavours are detected by the G protein-coupled receptors?
Sweet, bitter, and umami
How does the degree of dissociation of a food acid impact sourness?
Most acids in foods are weak acids. By increasing [H+], pH decreases, and the decrease in pH makes the food more sour. Any pH below 4.76 will keep the acid in pronated form and the product sour
How do flavour enhancers work?
Synergism occurs when a flavouring stimulus attaches to the tongue receptors in combination with an or all of the following: MSG, IMP, or GMP. Different combinations provide stronger flavour signals to the brain. Bind with MSG has strongest flavour
Which pigments are important for the colour of meat?
Myoglobin, a protein complex made of blobulin and iron. The colour of meat is influenced by the oxidation state of iron in the myoglobin molecule. A bright pink colour is preferred
Colour of the reduced form of myoglobin?
Purple colour
Colour of the oxygenated form of myoglobin?
Bright red
Colour of the oxidized form of myoglobin?
Brown
How do emulsifying salts improve the texture of processed cheese?
Emulsifyings salts are added and Na ions from emulsifying salts and Ca ions from caseinate are exchanged, product is heated and becomes hydrophobic. Insoluble casein becomes unbound and emulsifies fat globules in cheese through hydrophobic reactions to create smooth texture
What is the chemical process of fermentation?
Undergoes aerobic respiration, where glucose is broken down to pyruvate (glycolysis - anaerobic process), and in the presence of oxygen, pyruvate moves into the mitochondria and takes part in Kreb’s Cycle and ETC. When oxygen is not present fermentation takes place
What is lactic acid fermentation?
Glucose –> ATP + lactic acid
lactic acid fermentation: yogurt example
- start of fermentation, ST is more active
- increased formic acid initiates growth of LAB by decreasing pH
What is alcohol fermentation?
Glucose –> ATP + alcohol + CO2
alcohol fermentation: beer foam
CO2 bubble stays stabilized due to Lipid Transfer Protein which is hydrophobic. It coats the CO2 bubble and binds with bitter iso-alpha acids to increase stability of foam
