5 grams of chilli powder sample is taken in a weighed and folded filter paper and is loaded into the main chamber of the Soxhlet extractor. The Soxhlet extractor is placed onto a flask . About 150 ml of solvent is added from the top of the extraction chamber . The Soxhlet is then equipped with a condenser. The solvent is heated to reflux. The solvent vapour travels up a distillation arm, and floods into the chamber housing the sample. The condenser ensures that any solvent vapour cools, and drips back down into the chamber housing the solid material. The chamber containing the solid material slowly fills with warm solvent. Some of the desired compound will then dissolve in the warm solvent. When the Soxhlet chamber is almost full, the chamber is automatically emptied by a siphon side arm, with the solvent running back down to the distillation flask. This cycle is allowed to repeat many times, over 10 hours.
During each cycle, a portion of the non-volatile compound dissolves in the solvent. After many cycles the desired compound is concentrated in the distillation flask.
After extraction, the extract is flash evaporated in a rotary evaporator to remove the solvent which is condensed and recovered. The oleoresin is condensed.
Similarly the solid waste of chilli after extraction is also dried to remove the solvent. The following data are obtained
Weight of filter paper = w1 gms
Weight of filter paper +chilli sample = w2 gms
Weight of empty flask = w3 gms
Weight of flask + oleoresin = w4 gms
Percentage of oleoresin = (w4-w3)/(w2-w1)
The solvent extraction experiment is conducted on the 4 varieties of chilli and each variety of chilli was extracted using 3 different solvents and % of oleoresin extraction was determined in each case.
Each oleoresin thus obtained was subjected to TLC to separate the components (other instrumental techniques such as GLC , HPLC, photocolor determination etc, were not performed due to lack of facilities).
Samples of oleoresin obtained are shown below in the photographs