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
N2 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 APPLICATIONS
This 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.