OPTIMIZATION, PRODUCTION AND SCALE UP OF DEBITTERED KINNOW BEVERAGE BY α-L-RHAMNOSIDASE PRODUCING YEAST

Abstract

α-L-Rhamnosidase is used for debittering the citrus juice by hydrolyzing bitter naringin to nonbitter prunin and rhamnose. The present study was carried out on fermentative production of debittered kinnow (Citrus reticulata Blanco) beverage using α-L-rhamnosidase producing yeast in order to utilize its immense potentiality in processed kinnow juice industry. The effect of percent yeast inoculum concentration (0.25-1.25 v/v), total soluble solids (12-16 °B), temperature (15-35 °C) and incubation time (12-60 h) were studied to optimize the production of α-L- rhamnosidase enzyme from Clavispora lusitaniae in kinnow juice. Results indicated that yeast showing maximum rhamnosidase activity (0.056 IU mL-1) in presence of yeast inoculum concentration (0.75% v/v), brix (13 °B), temperature (30±5 °C) and incubation time (48 h). Further, these optimized conditions were used in upscale production of debittered kinnow beverage. The physicochemical parameters of freshly prepared beverage TSS 13.00±0.20 °B, acidity 0.14±0.03%, pH 3.40±0.10, brix acid ratio 92.85±0.00, limonin 6.90±0.10 ppm, naringin 443.00±10.00 ppm, total sugars 12.90±0.30%, reducing sugars 2.42±0.20 and ascorbic acid 27.80±1.00 mg/100 mL. All the physicochemical parameters did not change significantly during storage. The decrease of naringin with storage was 443.00±10.00 to 143.70±4.00 ppm due to the α-L-rhamnosidase activity of yeast. The percentage of ethanol and CO2 were 0.89±0.05% and 1.46±0.06 bar after three months of storage. All the sensory parameters like taste, color, aroma, bouquet, flavor and astringency of kinnow beverage were stable at storage period of 90 days with almost no change in organoleptic sensation. Thus the technology presented here, a very less time consuming and safe for production of debittered kinnow beverage on large scale in citrus food industries.