Lemon Juice Aroma Concentration by Reverse Osmosis

Ethanol, a major component of lemon juice, was analyzed to indicate degree of lemon juice aroma concentration. Aroma solution was concentrated from 12.2 to 23.4% ethanol at 8.3 MPa and 19°C by reverse osmosis. Ethanol rejected by the membrane decreased from the initial 87.7% to 78% at the final aroma concentration of 23.4% ethanol. Membrane rejection of neral, geranial, and terpinene-4-ol was > 96% while rejection of the alcohols, n-propanol, 2-methyl-3-buten-2-ol, and 3-methyl-2-buten-1-ol, ranged from 6.9% to 83.5%. Sensory analysis indicated no difference between initial aroma and aroma concentrated by reverse osmosis. Mass balance determined the true recovery of total volatiles was 79.7%. Loss of volatiles was attributed to adsorption in the polymeric matrix of the membrane and some loss was attributed to cleaning.