Comparison of two extraction methods (high pressure extraction vs. maceration) for the total and relative amount of hydrophilic and lipophilic organosulfur compounds in garlic cloves and stems. An application to the Italian ecotype “Aglio Rosso di Sulmona” (Sulmona Red Garlic)

Abstract

Garlic-based extracts have been surveyed as healthy promoting supplements in relation to their content of organosulfur compounds. The present study investigated the effect of high pressure extraction and maceration, and four extraction solvents (three hydroalcoholic mixtures and sunflower oil) on the total and relative amounts of the main organosulfur compounds of clove and stem extracts of the Italian ecotype “Aglio Rosso di Sulmona” (Sulmona Red Garlic). Organosulfur compounds were more abundant in cloves than in stem extracts. High pressure extraction led to higher recoveries of hydrophilic compounds than maceration whereas the highest amounts of lipophilic compounds were detected in macerates. A higher alliin-to-allicin conversion ratio was detected in clove, in comparison to stem extracts. Sunflower oil fostered allicin decay to compounds such as ajoenes, vinyldithiins and sulfides. The use of specific extraction methods may lead to standardised grade extracts, both from native raw materials and by-products.