Improved viability ofLactobacillus acidophilusNRRL-B 4495 during freeze-drying in whey protein-pullulan microcapsules

Abstract

In this research, pullulan was incorporated in protein-based encapsulation matrix in order to assess its cryoprotective effect on the viability of freeze-dried (FD) probiotic Lactobacillus acidophilus NRRL-B 4495. This study demonstrated that pullulan in encapsulation matrix resulted in a 90.4% survival rate as compared to 88.1% for whey protein (WPI) encapsulated cells. The protective effects of pullulan on the survival of FD-encapsulated cells in gastrointestinal conditions were compared. FD WPI-pullulan capsules retained higher survived cell numbers (7.10 log CFU/g) than those of FD WPI capsules (6.03 log CFU/g) after simulated gastric juice exposure. Additionally, use of pullulan resulted in an increased viability after bile exposure. FD-free bacteria exhibited 2.18 log CFU/g reduction, while FD WPI and FD WPI-pullulan encapsulated bacteria showed 0.95 and 0.49 log CFU/g reduction after 24 h exposure to bile solution, respectively. Morphology of the FD microcapsules was visualized by scanning electron microscopy.

Probiotics in Food Systems: Significance and Emerging Strategies Towards Improved Viability and Delivery of Enhanced Beneficial Value

“…Several materials have been applied for probiotic cells encapsulation, including polysaccharides (alginate, plant/microbial gums, chitosan, starch, k-carrageenan, cellulose acetate phthalate), as well as proteins (gelatin, milk proteins) and fats [155,156,157,158] (Table 1). Based on recent studies the use of gum or biopolymeric matrices can retain the viability of encapsulated probiotic cells compared to free ones, providing in many cases antimicrobial effects [159,160,161,162] against pathogenic or spoilage microorganisms.…”

Multifunctional Role of the Whey Culture Medium in the Spray-Drying Microencapsulation of Lactic Acid Bacteria

“…When the culture medium containing microorganisms was sprayed in the drier, the inlet and outlet temperature and atomizing pressure removed the water from the feed liquid (culture medium) and compacted the denatured whey aggregates, giving the microcapsules a rigid surface ( 62 ); however, the temperature in the drying chamber was not sufficient to evaporate the water (92% wet basis) and the core of the microcapsules had a high moisture content ((12.7±0.2) % wet basis, Table 2 ). Çabuk and Harsa ( 63 ) also reported this high moisture content of >10% (wet basis), with high survival rates of L. acidophilus NRRL B-4495, and they concluded that it is not possible to establish a correlation only based on the moisture content. However, the capsules with high moisture content may create a microenvironment in which the microorganism can repair the damage to the cell membrane after spray drying.…”

“…The diameter values of the optimized powder and culture medium powder were (<13.7±0.3) μm ( Table 2 ). In industrial production, capsule sizes below 100 μm prevent gritty or sandy undesirable textural properties in the food product ( 63 ). Therefore, the powder product obtained in this study had the correct size for use in functional foods.…”

Enhancing Bioavailability of Probiotics using Microencapsulation

“…Polysaccharides like starch, chitosan, carrageenan, alginate and different gums, proteins like gelatin, milk proteins like casein and whey protein, and soy protein as well as fats are few of the researched materials for microencapsulation in the food industry. [23][24][25][26] 2.1.1. Chitosan Food-grade bio-polymers are readily available, low-cost and effective as physical barriers imparting the desired protection to the bacterial core.…”