Aim: Estimation nutritive value of ghee sample (Desi Ghee)
Materials: Ghee sample
Laboratory equipment:
Soxhlet apparatus, Fat
extraction solvent (e.g., hexane or petroleum ether), Rotary evaporator, Oven, Spectrophotometer
(e.g., UV-Vis or FTIR)
Chemical reagents:
Sodium hydroxide
(NaOH)
Hydrochloric acid
(HCl)
Phenolphthalein
indicator
Vitamin A and E
standards
Procedure
1. Moisture Content Determination
Weigh 5-10g of ghee
into a pre-dried aluminum dish.
Place the dish in a
105°C oven for 2-3 hours.
Cool and weigh the
dish again.
Calculate the moisture
content using the formula:
Moisture
content (%) = ((Initial weight - Final weight) / Initial weight) × 100
2. Fat Extraction and
Determination
Weigh 10-20g of ghee
into a Soxhlet apparatus.
Extract the fat using
a solvent (e.g., hexane or petroleum ether) for 4-6 hours.
Evaporate the solvent
using a rotary evaporator.
Weigh the extracted
fat and calculate the fat content using the formula:
Fat
content (%) = (Extracted fat weight / Initial ghee weight) × 100
3. Vitamin A and E
Determination
Prepare a solution of
ghee in a solvent (e.g., hexane or petroleum ether).
Measure the absorbance
of the solution at 325nm (Vitamin A) and 292nm (Vitamin E) using a
spectrophotometer.
Compare the absorbance
values to those of Vitamin A and E standards to estimate the concentrations.
4. Cholesterol
Determination
Prepare a solution of
ghee in a solvent (e.g., hexane or petroleum ether).
Add a known amount of
sodium hydroxide (NaOH) to the solution.
Measure the absorbance
of the solution at 550nm using a spectrophotometer.
Compare the absorbance
value to that of a cholesterol standard to estimate the concentration.
5. Fatty Acid Composition Determination
Prepare a solution of
ghee in a solvent (e.g., hexane or petroleum ether).
Analyze the solution
using gas chromatography (GC) or high-performance liquid chromatography (HPLC)
to determine the fatty acid composition.
Calculations:
Calculate the
nutritive values based on the results obtained from the above steps.
Moisture content (%)
Fat content (%)
Vitamin A and E concentrations (μg/100g or mg/100g)
Cholesterol concentration (mg/100g)
Fatty acid composition (%)
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