A Comparison of Thermal Processing, Freeze Drying and Forward Osmosis for the Downstream Processing of Anthocyanin from Rose Petals

This study is aimed at extracting and concentrating natural pigment anthocyanin from rose petals for the possible usage in foods. The enriched extractions of anthocyanin from rose petals were performed by different methods such as: liquid N-2 treatment, sonication, usage of alcohol and freeze-thawing. Freezing-thawing the rose petals with solvent prior to grinding resulted in 18% higher extraction of anthocyanin. The enriched rose extract anthocyanin was further subjected to concentration by thermal evaporation, freeze drying and forward osmosis. Forward osmosis concentration process resulted in minimum degradation of anthocyanin (10.17 mg/L) as compared with other methods. The enriched rose extract anthocyanin (color) (5 mL) was supplemented to yoghurt and stored in refrigerated condition for a period of 2 weeks, which showed first-order degradation of anthocyanin at a rate of 31.8 mg/L. Practical ApplicationsThis study deals with the enriched extraction and concentration of anthocyanin from rose petals using different methods. Freezing-thawing followed by grinding the rose petals with water results in higher extraction of anthocyanin from rose petals. Forward osmosis concentration results in minimum degradation of anthocyanin as compared with thermal evaporation and freeze drying. The processed rose anthocyanin can be supplemented to food product to prepare rose colored yoghurt and stored up to 2 weeks.