SOP: Moisture and Volatile Matter in Oils and Fats

GIFSQ — Global Institute for Food Safety & Quality

Principle

Water in fats tends to settle when the fat softens and melts, so the sample is thoroughly mixed to distribute it uniformly before analysis. The moisture and other volatile matter are driven off by drying the sample in an oven at 105°C, and the loss in weight gives the moisture and volatile matter content. All the impurity determinations of this chapter can be done in series on the same sample.

Apparatus required

• Tared dish (previously dried and cooled in a desiccator)
• Oven, at 105°C (AOCS recommendation: 101°C ± 1°C)
• Desiccator
• Mixer

Procedure

Mix the sample thoroughly to distribute the water uniformly; soften solid fats with gentle heat but do not melt them; mix thoroughly with a mixer

↓

Weigh accurately 5 g of the sample into the tared dish which had been previously dried and cooled in a desiccator

↓

Dry in an oven at 105°C (AOCS recommendation: 101°C ± 1°C); remove from the oven, cool in a desiccator and weigh

↓

Repeat the procedure until the loss in weight does not exceed 0.05% per 30 min drying period

Calculation

                             Loss in weight
% Moisture and volatile matter = ──────────────── × 100
                                 Wt of sample

References

Ranganna, S., Handbook of Analysis and Quality Control for Fruit and Vegetable Products, 2nd edition.

Official and Tentative Methods, 3rd edn., American Oil Chemists’ Society, Vol. 1, Ca 4-25 (1975) — cited in the book.