Lecture 8 Flashcards

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1
Q

why is vitamin anaylis in food important?

A
  • assesing diet adequacy
    • nutrtion labelling
    • determing the effect of food processing
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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
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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)
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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
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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

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4
Q
  • what are the three categories of anayltical methods for quanitifying vitamins
A
  1. biological tests: Vit D, B12
    1. microbiological test: Vit B3, B9
    2. Physiochemical tests: A,C,E,B1,B2
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4
Q
  • what are some physio chemical techinques?
A
  • titration
    • spectrophotometry
    • Fluorometry
    • chromotagraphy
    • enzymatic
    • immunological
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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
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