Co-encapsulation efficiency of silk sericin-alginate-prebiotics and the effectiveness of silk sericin coating layer on the survival of probiotic Lactobacillus casei

Purification and drying methods of sericin from Bombyx mori cocoons

Different methods of purification and drying of sericin were evaluated to obtain a material free of contaminating residues through the development of safer and sustainable environmental technology. Samples purified using different proportions of alcohol solvents and by freezing/thawing were compared, while drying was performed by lyophilisation and atomisation in a spray. No significant statistical differences were observed in the yield of the purification process compared with the evaluated methods. Thus, the freezing/thawing method has economic and environmental advantages over other methods. Drying by spraying and lyophilisation produced particles exhibiting different properties in terms of structure: β-sheets, random sheets, and β-turns. In general, these particles are amorphous. The particles obtained by spray drying were more luminous, soluble, and spherical. Thus, purification by freezing/thawing and drying by spray can be considered appropriate methodologies for obtaining contaminant-free sericin through sustainable environmental technology.

Encapsulation of probiotic Lactobacillus acidophilus ATCC 4356 in alginate-galbanum (Ferula Gummosa Boiss) gum microspheres and evaluation of the survival in simulated gastrointestinal conditions in probiotic Tahini halva

One of the famous traditional confectionery products is Tahini halva. The aim of this study was the production of probiotic halva using free Lactobacillus acidophilus (FLA) and microencapsulated Lactobacillus acidophilus (MLA) with sodium alginate and galbanum gum as the second layer. The survival rate of MLA and FLA during heat stress, storage time, and simulation gastrointestinal condition in Tahini halva was assessed. The survival rates of MLA and FLA under heat stress were 50.13% and 34.6% respectively. During storage in Tahini halva, the cell viability loss was 3.25 Log CFU g-1 and 6.94 Log CFU g-1 for MLA and FLA, separately. Around 3.58 and 4.77 Log CFU g-1 bacteria were reduced after 6 h of exposure in simulated gastrointestinal conditions, for MLA and FLA respectively. These results suggest that the use of alginate and galbanum gum is a promising approach to protecting L. acidophilus against harsh environmental conditions.

Membrane Emulsification as an Emerging Method for Lacticaseibacillus rhamnosus GG® Encapsulation

Techniques capable of producing small-sized probiotic microcapsules with high encapsulation yields are of industrial and scientific interest. In this study, an innovative membrane emulsification system was investigated in the production of microcapsules containing Lacticaseibacillus rhamnosus GG® (Lr), sodium alginate (ALG), and whey protein (WPI), rice protein (RPC), or pea protein (PPC) as encapsulating agents. The microcapsules were characterized by particle size distribution, optical microscopy, encapsulation yield, morphology, water activity, hygroscopicity, thermal properties, Fourier-transform infrared spectroscopy (FTIR), and probiotic survival during in vitro simulation of gastrointestinal conditions. The innovative encapsulation technique resulted in microcapsules with diameters varying between 18 and 29 μm, and encapsulation yields > 93%. Combining alginate and whey, rice, or pea protein improved encapsulation efficiency and thermal properties. The encapsulation provided resistance to gastrointestinal fluids, resulting in high probiotic viability at the end of the intestinal phase (> 7.18 log CFU g-1). The proposed encapsulation technology represents an attractive alternative to developing probiotic microcapsules for future food applications.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s11947-023-03099-w.