5 chemical score this is based on the chemical

5.) Chemical score - This is based on the chemical analysis of the protein for the composition of essential
amino acids which is then compared with a reference protein (usually egg protein). The chemical score is
defined as the ratio between the quantity of the most limiting essential amino acid in the test protein to the
quantity of the same amino acid in the egg protein, expressed as percentage.
mg of the limiting amino acid / g test protein × 100
mg of the same amino acid / g egg protein
The chemical score of egg protein, for any one of the essential amino acids, is taken as 100 and the rest of
the proteins are compared.Chemical scores of foods are as follows : eggs – 100; meat – 70; milk cow – 65;
liver – 66; fish – 60; rice – 60; soybean – 57; Bengal gram – 44; groundnuts – 44; wheat – 42; sesame – 40;
and gelatin – 0.

CHAPTER 11. ANALYSIS OF FAT AND WATER SOLUBLE VITAMINS
Vitamin Analysis
Definition and Importance; Vitamins are defined as relatively low-molecular weight compounds which
humans, and for that matter, any living organism that depends on organic matter as a source of nutrients,
require small quantities for normal metabolism. With few exceptions, humans cannot synthesize most
vitamins and therefore need to obtain them from food and supplements. Insufficient levels of vitamins result
in deficiency diseases[e.g., scurvy and pellagra, which are due to the lack of ascorbic acid (vitamin C) and
niacin, respectively].
Importance of Analysis; Vitamin analysis of food and other biological samples has played a critical role in
determining animal and human nutritional requirements. Furthermore, accurate food composition
information is required to determine dietary intakes to assess diet adequacy and improve human nutrition
worldwide.
Vitamin Units; When vitamins are expressed in units of mg or μg per tablet or food serving, it is very easy
to grasp how much is present. Vitamins can also be expressed as international units (IU), United States
Pharmacopeia (USP) units, and% Daily Value (DV). To many, these definitions are unclear.
Vitamin assays can be classified as follows:
1. Bioassays involving humans and animals.
2. Microbiological assays making use of protozoan organisms, bacteria, and yeast.
3. Physicochemical assays that include spectrophotometric, fluorometric, chromatographic, enzymatic,
immunological, and radiometric methods.
Extraction Methods
Vitamin assays in most instances involve the extraction of a vitamin from its biological matrix prior to
analysis. This generally includes one or several of the following treatments: heat, acid, alkali, solvents, and
enzymes.Typical extraction procedures are as follows:
• Ascorbic acid: Cold extraction with metaphosphoricacid/acetic acid.
• Vitamin B1 and B2: Boiling or autoclaving in acid plus enzyme tre atment.