engleski

Recycling of food factory by-products: Supercritical extraction of yarrow herbal dust from filter tea factory

INTRODUCTION: During the production of filter tea a certain amount of herbal material of particle size lower than the size of pores of filter bag material is produced. This kind of material, usually called „herbal or fruit dust“, is discharged from the production as by- product or waste. Among aromatic herbs in Serbia yarrow is one of the mostly used in such form of production. During yarrow processing approximately 15% of raw material is converted in to “herbal dust”. Yarrow is medicinal plant widely used in traditional medicine for various forms of disorders. The main active compounds of yarrow are flavonoids, tannins, coumarins, sterols, salicylic acid, isovaleric acid and asparagine, but the most important compound in yarrow is essential oil and containing aromatic compounds. Having in mind main bioactive compounds and nature of this kind of material the application of supercritical extraction by carbon dioxide could be one of the possible choices for yarrow herbal dust recycling and utilization. Supercritical extraction by carbon dioxide represent the green environmentally friendly technology. In comparison to others extraction it enable production of “ready to use” solvent free extracts. OBJECTIVES: The main objective of this study was to apply supercritical carbon dioxide for production of low polar yarrow extracts with high concentration of aromatic bioactive compounds and no trace of extraction solvent. During investigation influence of main process parameters on extraction yield and extracts composition was analysed. METHOD / DESIGN: Supercritical carbon dioxide extraction of yarrow herbal dust was performed at two different temperatures (40 and 60°C) and three different pressures (100, 200 and 300 bar). Extraction yield was measured after 30 min, 1, 1.5, 2, 3 and 5 hours, and using these results extraction kinetics was analysed. By application of GC/MS and GC FID qualitative profile and concentration of main aromatic compounds in obtained supercritical extracts was analysed. RESULTS: Total extraction yield was in the rage from 0.769 to 6.003%, and it was increased with increase of process pressure. The highest extraction yield was obtained by application of supercritical carbon dioxide at pressure of 300 bar and temperature of 40 ºC, while lowest was observed at pressure of 100bar and temperature of 60 ºC. In obtained extracts several aromatic constituents has been detected, among most important were: p-cimen, linalool, 4-terpineol, trans caryophyllene, eucalyptol, camphor, borneol, and gama and alpha terpinene. Dominant compounds in all extracts were eucalyptol and camphor. Highest concentration of both compounds (1.56 for eucalyptol and 3.52 g/100g of extracts for camphor) has been obtained in extract prepared using supercritical carbon dioxide at pressure of 200 bar and temperature of 60 ºC. CONCLUSIONS: This study has showed that yarrow herbal dust represent a valuable by-product of food industry, in mean high concentration of bioactive compounds, especially aromatic ones e.g. eucalyptol and camphor. Application of supercritical carbon dioxide extraction could be the solution for such material utilization. In extraction process parameters impacted on extraction efficiency, therefor for higher process efficiency and better product/extract quality higher pressures e.g. 300 bar should be applied.

supercritical extraction; by-product; herbal dust; yarrow; camphor; eucaliptol

nije evidentirano