Encapsulation of Lacticaseibacillus casei TCS using a Pickering water-in-oil-in-water double emulsion to preserve bacterial viability and aroma characteristics in yogurt

A Pickering water-in-oil-in-water (W 1 /O/W 2 ) double emulsion was used to encapsulate Lacticaseibacillus casei TCS ( L. casei TCS), a strain used as a starter culture in yogurt production, by cross-linking β-cyclodextrin (β-CD), octenyl succinic anhydride (OSA) starch, Gum Arabic (GA), with the aim of improving its survival and viability during freeze-dried and subsequent storage. Optical microscope, Scanning electron microscope (SEM), laser particle size analyzer, Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), and X-ray diffraction analysis (XRD) were used to measure the morphological characteristics of microcapsules. The microencapsulated capsules exhibited a smooth surface and a dense microstructure, with a particle size of 34.10 μm and an impressive encapsulation efficiency of 94.33 %. Encapsulation significantly improved L. casei TCS survival rates to 90.63 % (vs. 83.07 % for free cells) post-freeze-drying and maintained higher viability after 42 days of storage. The encapsulated L . casei TCS was subsequently added to milk for yogurt fermentation, and the results of gas chromatography-mass spectrometry (GC-MS) and sensory evaluation demonstrated a superior contribution to flavor in yogurt compared to free cell. The findings suggested that encapsulated LAB starter culture using a W 1 /O/W 2 type Pickering emulsion can enhance their viability and metabolic activities in the food industry. • A W 1 /O/W 2 type Pickering emulsion was prepared by β-CD, OSA, GA and Span 80. • Analysis of morphological characteristics of L. casei TCS microcapsules. • Encapsulated L. casei TCS exhibited higher viability during starter storage period. • Starter encapsulation improved sensory properties and volatile compounds of yogurt.