Development of low alcoholic naturally carbonated fermented debittered beverage from grapefruit (Citrus paradisi)

A pure yeast Clavispora lusitaniae, isolated from whey beverage, phenotypically characterized and molecularly characterized by sequencing of D1/D2 domain of 26S rRNA and Internal Transcribed Spacer (ITS) region was used to produce low alcoholic naturally carbonated fermented debittered beverage from Grapefruit. C. lusitaniae produces enzyme naringinase. This enzyme is a mixture of I±-L-rhamnosidase and I²-D-glucosidase. The bitter component in citrus fruit, naringin can be hydrolyzed by I±-L-rhamnosidase to rhamnose and prunin then by I²-glucosidase to glucose and naringenin. The freshly prepared fermented Grapefruit beverage had TSS 14 °B, pH 4.7, acidity 0.26%, brix acid ratio 53.85, total sugars 11.6%, reducing sugars 3.34%, ascorbic acid 21.9 mg/100 ml, naringin 643.2 ppm, alcohol 0.00% (v/v), CO2 0.00 bar and total yeast count 5.83 (Log no.of cells/ml). Physico-chemical changes recorded after three months of storage at refrigerated temperature revealed TSS 12.0 °B, pH 4.2, acidity 0.54%, brix acid ratio 22.22, total sugars 8.97%, reducing sugars 1.94%, ascorbic acid 18.45 mg/100 ml, naringin 365.2 ppm, alcohol 0.76 % (v/v), CO2 1.35 bar and total yeast count 8.54 (Log no.of cells/ml). Naturally produced CO2 by C. lusitaniae during fermentation adds effervescence, sparkle, tangy taste to the beverage in addition to its antimicrobial properties. Thus bio-enzymatic debittering by C. lusitaniae may become the new direction of citrus juice processing in the future, due to its economical viability with strong ability to remove the bitter taste from citrus juice beverage.