Food Protein Analysis Flashcards
1
Q
what is food protein analysis
A
the use of reliable quantitative methods to determine the total protein content of foods and food ingredients
2
Q
why do we need food protein analysis
A
to establish nutrient values/ content
to regulate safety specifications
to avoid risks to the public health
3
Q
what are the methods of food protein analysis
A
Kjeldahl method and Dumas method
- nitrogen based methods that rely on total nitrogen determination to estimate protein content
4
Q
what are the advantages of the Kjeldahl method and Dumas method
A
- cheap and fast
5
Q
what are the disadvantages of the Kjeldahl method and Dumas method
A
- cannot distinguish protein-based nitrogen from non-protein based nitrogen
6
Q
what is the Kjeldahl method
A
- quantifies the total protein content of foods by direct nitrogen measurement and subsequent multiplication by a conversion factor of 6.25
The total organic nitrogen content is analysed by:
- digestion to convert nitrogen to ammonium sulfate
- neutralisation with alkali to convert ammonium sulphate to free ammonia
- distillation of ammonia to boric acid
- titration of excess boric acid with alkali
- takes 3 hours
- the use of sulfuric acids presents safety concerns
7
Q
what is the Dumas method
A
- total nitrogen is measured by gas chromatography and the nitrogen protein conversion factors are used to calculate the total protein content
- simple, cheap, safe
- takes 3 minutes
8
Q
Name some other emerging methods of food protein analysis
A
- antibody based methods
- enzyme-linked immunosorbent assays
- chromatographic methods
- electrophoretic methods
- mass spectrophotometry
