Lecture 8 Flashcards
1
Q
why is vitamin anaylis in food important?
A
- assesing diet adequacy
- nutrtion labelling
- determing the effect of food processing
2
Q
- why are extraction procedures specific to each vitamin, what is the purpose of extraction and how may it be done?
A
- because very diverse chemical structures
- designed to stabilize it
- treated with heat, acid, alkali, solvents or enzymes
- designed to stabilize it
3
Q
- what are influencing factors in extraction
A
- antioxidants added to inhibit oxidantion (vit a,b9)
- addition of chelating agents (vit c in fortified or food with iron)
- pH (vit c)
- light (should be kept away from vit a and B2)
- heat (B9)
4
Q
- describe biological methods
A
- for vit B12 and D
- feed animals then sacrifice them to measure for example vitamin D content based on bone calcifcation
- not done very often due to cost, ethics, length
4
Q
- describe microbiological methods
-
A
vit are growth fatcors for microogranisms
- only for water soluble vit
- used to measure B complex vitamins by measuring growth of microogranisms that need those vit to grow
- use of calibration curve (known vit [] to estimate vit content from food)
- growth of microogranism is proportional to their specific vit requirments
- measuring of microgranims through carbon dioxide production, turbidity, acid production, gravimetry, respiration
4
Q
- what are the three categories of anayltical methods for quanitifying vitamins
A
- biological tests: Vit D, B12
- microbiological test: Vit B3, B9
- Physiochemical tests: A,C,E,B1,B2
4
Q
- what are some physio chemical techinques?
A
- titration
- spectrophotometry
- Fluorometry
- chromotagraphy
- enzymatic
- immunological
4
Q
- when choosing a method what factors need to be considered?
A
- accuracy and precision of method
- info needed on bioavability
- time needed
- intrustments needed
- staff needed
- food matrix being anaylzed
- number of samples need
- regulatory requirments
