Processing of marjoram (Marjorana hortensis Moench.) and rosemary (Rosmarinus officinalis L.). Effect of blanching methods on quality.

Marjoram and rosemary were blanched for 1 min by dipping in boiling water, exposing to steam or exposing to microwave radiation. Blanched and unblanched herbs were dried in a microwave oven, packaged and analysed for quality parameters (volatile oil content, colour, texture, chlorophyll and ascorbic acid content). Blanched samples retained their original colour to a greater extent than unblanched samples, but had lower contents of volatile oils. Water-blanched samples had the best chlorophyll retention. Microwave blanched herbs had the best ascorbic acid retention (21.5 and 33.0 mg/100g in marjoram and rosemary, respectively, corresponding to 79.4 and 49.9% retention) and the firmest texture on the basis of compression force values.