Lipid Analysis
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| Physical characteristics, iodine value, saponifcation value, and free fatty acids are all methods to analyze ______. | bulk fat or oil
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| Measuring present status and evaluating stability are methods to analyze _____. | lipid oxidation
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| GC and TLC are methods to analyze _____. | lipid fractions
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| Fat ____ with solvents is typically required before fat _____ if not bulk fat or oil. | extraction, chracterization
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| Name three ways to minimize oxidation of fats. | Addition of antioxidants, flush with nitrogen, avoid heat/light.
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| Name three physical characterization methods for bulk fats and oils. | Refractive index, melting point, cold test, cloud point, spreadability.
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| Solid fat index is measured using _____ and is plotted as ____ vs _____. | dilatometry, volume, temperature
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| Solid fat content is measured using continuous wave or pulsed _____. | NMR
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| _____ can be used to determine the actual percentage of fat in a sample. | SFC (solid fat content)
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| _____ is a measure of degree of unsaturation. | Iodine value
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| Define iodine value. | The number of grams of iodine absrobed by 100 g of sample.
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| _____ gives the average molecular weight of triglycerides in a sample. | Saponification value
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| Define saponification value. | The number of mg of KOH required to saponify (give salt and glycerol) 1 g of sample.
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| _____ measures the fatty acids liberated upon hydrolysis of triglycerides. | Free fatty acids
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| ____ are an indication of adequacy of refining. | Free fatty acids
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| ____ are the primary products of oxidation. | Peroxides
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| Define peroxide value. | Number of mEq of peroxides per 1 kg sample.
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| A freshly refined or very rancid oil will have a peroxide value of ____. | zero
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| _____ estimates the amount of unsaturated aldehydes (secondary oxidation products) in a sample. | p-anisidine value
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| _____ indicates total oxidation using both peroxide and p-anisidine values. | Totox value
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| _____ is a secondary oxidation product responsible for off flavors/odors. | Hexanal
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| T or F: Lipid extraction is required for hexanal measurement. | False
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| The TBARs test measures a secondary oxidation product known as _____. | malonaldehyde
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| What is the disadvantage of TBARs test? | Method is not very sensitive.
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| T or F: TBARs correlates better with sensory evaluation than peroxide value. | True
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| ____ is usually used to measure lipid oxidation in meat products. | TBARs test
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| Conjugated dienes absorb at ____ nm. | 232
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| Conjugated trienes absorb at ____ nm. | 270
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| How should oxidative stability be evaluated? | 1. Subject sample to oxygen or heat
2. Monitor oxidation over time with present status test.
3. Determine the induction period before rancidity.
4. Use accelerated shelf-life studies
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| What can be fractionalized with gas chromatography? | Fatty acids, trans isomers, glycerols, cholesterol
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| What can be fractionalized with IR? | Trans isomers
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| What can be fractionalized with HPLC? | Glycerols, lipid soluble pigments/vitamins
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| What can be fractionalized with TLC? | Glycerols
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| How is Olestra analyzed in lipid fractions? | Lipase enzyme is used to breakdown triglycerides and then is precipitated with calcium.
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