Abstract:

The microwave-assisted extraction of proanthocyanidins (PC) from Rosa davnrica Pall. seeds was optimized using
the response surface methodology. The PC content of Rosa davnrica Pall. seeds was determined to be (1.55 ± 0.12) g/100 g
by iron salt catalysis method. The results of one-factor-at-a-time experiments showed that the addition of 0.2% sodium
hexametaphosphate (SH) provided the best stability for the proanthocyanidins. Extraction time, solid to liquid ratio,
microwave power, and ethanol concentration were selected as independent variables, while the extraction yield of PC was
taken as response variable. The optimization was carried out based on Box-Behnken experimental design by investigating
the individual and combined effects of the four factors on the response variable. The optimum extraction conditions were
determined as follows: extracting time, 70 s; material to liquid ratio, 1:20 (g/mL); microwave power, 360 W; and ethanol
concentration, 60%. Under these conditions, the PC yield in one extraction cycle obtained was 72.58% with a relative error
of 1.12% as compared with the model prediction of 73.46% indicating that these parameters are reliable. In first three cycles,
93.19% of the measured PC were extracted.

Key words: Rosa davnrica Pall. seeds, proanthocyanidins, response surface methodology, extraction process