Effect on Viability of Microencapsulated Lactobacillus rhamnosus with the Whey Protein-pullulan Gels in Simulated Gastrointestinal Conditions and Properties of Gels

Abstract

Lactobacillus rhamnosus GG (LGG) has low resistance to low pH and bile salt in the gastrointestinal juice. In this study, the gel made from whey protein concentrate (WPC) and pullulan (PUL) was used as the wall material to prepare the microencapsulation for LGG protection. The gelation process was optimized and the properties of gel were also determined. The results showed the optimal gel was made from 10% WPC and 8.0% PUL at pH 7.5, which could get the best protective effect; the viable counts of LGG were 6.61 Log CFU/g after exposure to simulated gastric juice (SGJ) and 9.40 Log CFU/g to simulated intestinal juice (SIJ) for 4 h. Sodium dodecyl sulphite polyacrylamide gel electrophoresis (SDS-PAGE) confirmed that the WPC-PUL gel had low solubility in SGJ, but dissolved well in SIJ, which suggested that the gel can protect LGG under SGJ condition and release probiotics in the SIJ. Moreover, when the gel has highest hardness and water-holding capacity, the viable counts of LGG were not the best, suggesting the relationship between the protection and the properties of the gel was non-linear.

Effect of pullulan concentration and pH on the interactions between whey protein concentrate and pullulan during gelation

“…In the previous study, the WPC/PUL gel with LGG was freeze-dried into the microencapsulation to evaluate the resistance to the stimulated gastrointestinal juice. 1 Therefore, the gel (0.50 g mL -1 WPC, 0.40 g mL -1 PUL and pH 7.5) in the present study was freeze-dried. Then, WPC and the gel powder were solved with distilled water to 1.0 g L -1 and adjusted to pH 2.0-7.5, respectively, which were then used to evaluate the zeta-potential of the gel at different pH.…”

“…For probiotics to colonize and function in the gut, an effective delivery system must be constructed. 1 Because it is non-toxic and can be absorbed and utilized in the gut, edible gel has gradually become the primary choice for probiotics as a protective material. 2 Whey protein, a by-product of cheese production, has good nutritional and functional properties and is often used as a raw material for the preparation of edible gels.…”

“…After exposure to the simulated gastrointestinal juice test, the best protective effect was obtained when the gel was prepared using 0.50 g mL -1 WPC and 0.40 g mL -1 PUL at pH 7.5. 1 Çabuk and Harsa 6 also showed that microcapsules made from whey protein isolate (WPI)-PUL could resist simulated gastric acid and bile salt, and improve the stability of Lactobacillus acidophilus NRRL-B 4495 coated with the microcapsules after storage.…”

Whey Protein Concentrate, Pullulan, and Trehalose as Thermal Protective Agents for Increasing Viability of Lactobacillus plantarum Starter by Spray Drying

“…As a kind of non-reductive stable polysaccharide, pullulan with strong oxygen resistance has high mechanical strength and low permeability compared with other saccharides (Yuen, 1974). The use of WP and pullulan gel for preparing lactic acid bacteria microcapsules has been reported (Zhang et al, 2019). Trehalose could be used as an excipient in the drying process to stabilize protein structure because of its stable efficacy and excellent processing properties (Mensink et al, 2017).…”

“…Pullulan is a neutral water-soluble extracellular polysaccharide that is produced by microbial and has lots of excellent properties such as heat resistance, solubility, non-hygroscopicity, and filmforming property (Singh et al, 2009). The L. plantarum was embedded by whey protein concentrate (WPC) and pullulan, and the viable counts was 7.24 Log CFU/g after spray drying (Zhang et al, 2019).…”