Effect of Osmotic Concentration through Polydimethylsiloxane Membrane on Aroma of Freeze-Dried Rose Hydrolat

In order to explore the effect of polydimethylsiloxane (PDMS) membrane pervaporation technology on the concentration of freeze-dried rose hydrolat (Rosa damascene), headspace solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) were used to analyze the volatile aroma components of freeze-dried rose hydrolat, and its sensory properties and applicability were evaluated by sensory analysis. The results showed that 54 aroma components were detected in rose hydrolat, and its characteristic aroma components including phenylethyl alcohol, citronellol and geraniol accounted for more than 90% of the total, indicating great utilization value. After two osmotic concentration cycles, the rose aroma became more intense and typical, and the content of benzene ring compounds significantly increased, characterized by total odor activity value (OAV) of rose aroma substances increased by 20.47%. The sensory flavor profile analysis also showed similar results: the proportion of floral aroma intensity (M value) increased from 37% to 51%, which was consistent with the result of partial least squares regression (PLSR) validation analysis. Additionally, it was found that the aroma intensity of freeze-dried rose hydrolat obtained after secondary osmosis was similar to that of rose essence sold in the market, and still higher than that of rose soda water sold in the market after 100-fold dilution, demonstrating its potential as a flavor enhancer in daily chemicals and beverages.