Effect of Particle Size and Solid-to-Solvent Ratio on Yield, Piperine Content, Volatile and Non-Volatile Contents of Black Pepper Oleoresin Extracts

Black pepper oleoresin is extensively applied as a natural flavoring ingredient in the food industry. It contains piperine which has various benefits for human health. However, limited research has been conducted on black pepper oleoresin extraction, especially regarding the influence of key parameters on the yield and quality of the oleoresin product. Therefore, this research determined the effect of particle size and the solid-to-solvent ratio on the yield and quality of black pepper oleoresin extracted using the soxtec method. Four different particle sizes and four solid-to-solvent ratios were evaluated using ethanol as the solvent. The moisture content of black pepper powder, the oleoresin yield, the piperine content and the volatile oil and non-volatile oil contents were determined. The moisture content of the black pepper powder was 12.5% whereas the oleoresin and volatile oil contents of black pepper were 16.2% d.b. and 3.9% d.b., respectively. Both the yield and piperine content of oleoresin significantly increased with decreasing particle size from 0.5 to <1 mm to smaller than 0.125 mm. A decrease in the solid-to-solvent ratio from 1:5 to 1:10 significantly increased the oleoresin yield; however, a ratio lower than 1:10 did not provide any significant increase in the oleoresin yield. Decreasing the solid-to-solvent ratio led to a significant increase in the piperine content of oleoresin only when the ratio decreased from 1:5 to 1:20. There were no significant effects of particle size or the solid-to-solvent ratio on the volatile oil and non-volatile oil contents in the oleoresin. A suitable particle size and solid-to-solvent ratio were below 0.125 mm and 1:10, respectively, regarding increased yield and piperine content in the oleoresin. These results have contributed to a better understanding of the key factors affecting the yield and piperine content of black pepper oleoresin and of the conditions suitable for black pepper oleoresin extraction which can be utilized in the food and pharmaceutical industries. Keywords: Black pepper oleoresin, Particle size, Piperine, Solid-to-solvent ratio, Soxtec method.