Microencapsulation of Lactobacillus rhamnosus ATCC 7469 by spray drying using maltodextrin, whey protein concentrate and trehalose

Abstract

This study aimed to microencapsulate Lactobacillus rhamnosus ( L. rhamnosus) ATCC 7469 with whey protein concentrate (WPC), maltodextrin and trehalose by spray drying and to assess the impact of microencapsulation on cell viability and the properties of the dried powders. Spray-drying conditions, including inlet air temperature, air flow rate and feed pump, were fixed as independent variables, while probiotic survival, moisture content, water activity and effective yield were established as dependent variables. The survival of encapsulated L. rhamnosus by spray drying was optimized with response surface methodology, and the stability of the powder was assessed. The optimum spray-drying conditions were an inlet air temperature, air flow rate and feed pump rate of 169 °C, 33 m3·h−1 and 16 mL·min−1, respectively, survival of 70%, air aspiration of 84% and outlet air temperature of 52 °C, achieving an overall desirability of 0.96. The physicochemical and structural characteristics of the produced powder were acceptable for application with regard to residual water content, hygroscopicity, water activity, and particle size. The results indicated that a protein-trehalose-maltodextrin mixture is a good wall material to encapsulate L. rhamnosus, showing important thermal protection during the drying process and increasing survival. However, a decrease in this capacity is observed at an air outlet temperature of approximately 101 °C. The possible effects of the wall materials and the drying conditions on survival are also discussed.

Materials Used for the Microencapsulation of Probiotic Bacteria in the Food Industry

“…All these features make them a perfect carrier for active substances and thus an ideal material for the microencapsulation of bacterial cells. Maltodextrins are produced from a variety of raw materials using different methods and processing conditions [ 83 ].…”

“…The material with which maltodextrins are often used in encapsulation is whey protein. In combination with maltodextrins, whey proteins form structures that effectively protect the core of the capsule and are susceptible to hardening in a calcium chloride solution [ 83 ]. For L. acidophilus La-5, a method of microencapsulation based on spray-drying with the use of soy extract and maltodextrin was proposed.…”

Influence of nitrogen sources on the tolerance of Lacticaseibacillus rhamnosus to heat stress and oxidative stress

“…Spray drying is cost-effective and highly flexible, and it is commonly used in the food industry (Martín et al 2015 ). Therefore, spray drying has been applied in the production of L. rhamnosus powder ( Prasad et al 2003 ; Moayyedi et al 2018 ; Agudelo-Chaparro et al 2021 ). However, spray drying results in a lower survival rate of starters compared to freeze-drying because the bacterial cells are exposed to severe heat and oxidative stress.…”

Transcriptome-phenotype matching analysis of how nitrogen sources influence Lacticaseibacillus rhamnosus tolerance to heat stress and oxidative stress

“…Spray drying is cost-effective and highly flexible and has been applied in the production of LAB powder [ 11 , 12 ]. Heat stress and oxidative stress are the major stresses resulting in a low survival rate of starter cultures during spray drying [ 13 , 14 ].…”