Appraisal of the combined effect of time and temperature on the total polyphenol yield in batch stirred-tank extraction of medicinal and aromatic plants: The extraction efficiency factor

Abstract

Medicinal and aromatic plants (MAPs) have always been a source of a vast variety of secondary metabolites with high biological potency. There is to-date an enormous ongoing research on the development of sophisticated methodologies for the production of bioactive MAP extracts, which may be applied in a spectrum of products, such as foods, pharmaceuticals and cosmetics. A great concern in implementing an extraction protocol is the use of appropriate conditions to achieve maximum efficiency with minimum cost, energy, and environmental aggravation. Although several parameters may affect the effectiveness of an extraction process, time and temperature are of utmost importance, and largely define both operating cost and quality of the final extract. Thus, there is a need for a simple tool of assessing an extraction method and allow for sound comparisons. In such a frame, this study introduces for the first time the concept of “extraction efficiency factor” (FEE). The purpose was to combine time (t) and temperature (T) in a single factor for evaluating extraction processes in general, and to enable easy and sound comparison of results obtained by solid-liquid extractions of MAPs. Such an approach could facilitate process control and would permit trading time and temperature of a treatment such that equivalent final effects are obtained.