Fat Analysis Quiz Flashcards
Fat generally refer to as
lipids that are solid at room temperature
Oils generally refer to as
lipids that are liquid at room temperature
Total fat (FDA definition)
Sum of fatty acids from C4 to C24 calculated as triglycerides
Fats
Esters of fatty acids with glycerol-triacyl-glycerols
Waxes
Esters of fatty acids with long-chain alcohols other than glycerols
Derived lipids
substances derived from neutral lipids or compound lipids
Lipids are soluble
in organic solvents and in soluble in water
Solvent extraction method for multicomponent food products
Acid Hydrolysis
Acid Hydrolysis can break
both covalently and ionically bound lipids into easily extractable lipid forms
Ideal solvent should have
high solvent power for lipids and low or no solvent power for proteins, amino acids and carbohydrates
Ideal solvent Pt.2
Evaporate readily
Leave no residue
Low boiling point
Nonflammable
Nontoxic
% Fat on Dry Weight Basis
(g of fat in sample/ g of dried sample) * 100
Example of semicontinuous extraction method
The Soxhlet Method
Example of discontinuous solvent extraction method
Mojonnier Method (does not require removal of moisture)
Total fat is calculated as
the sum of individual fatty acids expressed as triglyceride equivalents
Saturated and monounsaturated fats are calculated
as sum of respective fatty acids
% Fatty acid on a lipid basis
= mg/mg of fatty acid * 100
% fatty acid on a sample basis
= mg/mg of fatty acid * % lipid
% fatty acid
= (SRF/F) * (final sample volume (ml)) / sample weight (mg)) *100
SRF = Sample response factor
F = Standard Factor
Infrared (IR) method is based on
absorption of IR energy by fat at a wavelength of 5.73 um
Fat content by Foss-Let method is determined as a
Function of the specific gravity of a sample solvent extract
Lipids are generally defined by their
solubility characteristics rather than by some common structural feature
Necessary steps prior to analysis
Predrying
Particle size reduction
Acid Hydrolysis
Total Lipid content of is commonly determined by
organic solvent extraction methods
Classification of solvent extraction methods
Continuous (Goldfish)
Semicontinuous (Soxhlet)
Discontinuous (Mojonnier)
GC Analysis (for nutrition labeling)
