Simultaneous blending and fermentation of ToTu™ an egg-white drink with different fruit juices and probiotic lactic acid bacteria

Abstract

Egg-white drink (ToTu™) is an egg-based dairy alternative food in the market that can function as an effective probiotic carrier. In this study, the monocultural fermentation for the production of a probiotic egg-white drink blended with different fruit juices (strawberry, pineapple and peach) by two probiotic bacteria, Lacticaseibacillus casei 01 and Ligilactobacillus salivarius CRL 1328 strains was focused. Both probiotic bacteria strains grew very well in all blended samples. Starting with an initial cell count of around 7.35 logCFU/mL, the cell concentration of L. casei 01 strain reached 9.06 logCFU/mL, 8.97 logCFU/mL, and 8.83 logCFU/mL in the cases of egg-white blended with peach, pineapple and strawberry, respectively at the end of the fermentation process (24 hours). In the case of L. salivarius CRL 1382 strain, the cell counts of all blended samples increased significantly from 5 logCFU/mL to 8.12 logCFU/mL at 8-hour and remained unchanged. The pH values of all samples were in range of pH 3.76–4.07 after 24 hours. Slight changes in the colours of fermented products were detected. The protein profiles of drinks also changed favourably, the density of some proteins in EW, such as ovalbumin, ovomucoid and ovoflavoprotein decreased during fermentation. Rheological parameters exhibited pseudoplastic behaviour when pineapple was added to an egg-white drink and shear thickening fluid when peach and strawberry were incorporated. A total of 17 sensory attributes of 4 fermented samples were analysed by ProfiSens software, and overall, the highest score was counted in the egg-white drink blended with strawberry juice and fermented by Ligilactobacillus salivarius CRL 1328 strain sample. Meanwhile, the blended samples fermented by L. casei 01 strain can be stored in cold conditions for 8 weeks with a very minimal decrease in viable cell count, whereas by L. salivarius CRL 1328 strain, the viability of probiotic cells dropped drastically (about 50 % when storage for 4 weeks). Our results contributed valuable information to the development of probiotic egg-white drinks blended with fruit juices.