Production of low-alcoholic naturally carbonated fermented debittered beverage from W. Murcott mandarin (Citrus reticulata) by naringinase producing yeast

The processing of citrus fruits to beverages has encountered commercial restrictions due to their undesirable bitter taste, which is attributed to the presence of naringin. The biotechnological potential of microbial naringinase has drawn great attention from scientists worldwide for enzymatic debittering of citrus fruit juices. The novel yeast isolate Clavispora lusitaniae mutant has been isolated and characterized moleculary and biochemically in the Department of Microbiology, Punjab Agricultural University. Yeast produces naringinase, mixture containing α-L-rhamnosidase and β-Dglucosidase. Naringin is hydrolyzed by α-L-rhamnosidase to rhamnose and prunin then by β-glucosidase to glucose and naringenin. Bitterness of prunin is 1/3 rd of that of naringin. Thus it is a reliable, controllable, reproducible technology, and especially safeguards the interest of horticulturists during seasonal glut of the fruits. The freshly prepared fermented W.Murcott (Citrus reticulata) beverage had TSS 14°B, pH 4.4, acidity 0.25%, Brix acid ratio 56.0, total sugars 10.4%, reducing sugars 3.24%, ascorbic acid 25.60 mg/100 ml, naringin 410.5 ppm, alcohol 0.00% (v/v), CO 2 0.00 bar and total yeast count 5.70 (Log no. of cells/ml). Physicochemical changes recorded after three months of storage at refrigerated temperature revealed TSS 11.0°B, pH 3.95, acidity 0.53%, Brix acid ratio 21.75, total sugars 8.5%, reducing sugars 2.64%, ascorbic acid 20.04 mg/100 ml, naringin 164.30 ppm, alcohol 0.91% (v/v), CO 2 1.35 bar and total yeast count 8.93 (Log no. of cells/ml). Naturally produced CO 2 by Clavispora lusitaniae during fermentation adds effervescence, sparkle, tangy taste to the beverage in addition to its antimicrobial properties.