Drying of probiotics to enhance the viability during preparation, storage, food application, and digestion: A review

Abstract

Functional food products containing viable probiotics have become increasingly popular and demand for probiotic ingredients that maintain viability and stability during processing, storage, and gastrointestinal digestions. This has resulted in heightened research and development of powdered probiotic ingredients. The aim of this review is to overview the development of dried probiotics from upstream identification to downstream applications in food. Free probiotic bacteria are susceptible to various environmental stresses during food processing, storage, and after ingestion, necessitating additional materials and processes to preserve their activity for delivery to the colon. Various classic and emerging thermal and nonthermal drying technologies are discussed for their efficiency in preparing dehydrated probiotics, and strategies for enhancing probiotic survival after dehydration are highlighted. Both the formulation and drying technology can influence the microbiological and physical properties of powdered probiotics that are to be characterized comprehensively with various techniques. Furthermore, quality control during probiotic manufacturing and strategies of incorporating powdered probiotics into liquid and solid food products are discussed. As emerging technologies, structure‐design principles to encapsulate probiotics in engineered structures and protective materials with improved survivability are highlighted. Overall, this review provides insights into formulations and drying technologies required to supplement viable and stable probiotics into functional foods, ensuring the retention of their health benefits upon consumption.

The Impact of Physicochemical Conditions on Lactic Acid Bacteria Survival in Food Products

“…Thermophilic LAB strains can tolerate temperatures up to 65 • C, but in general heat stress above 50 • C is harmful to most LAB. [26]. The extent of cell heat injuries depends on the duration and severity of the heat stress and in severe form can lead to death.…”

“…Another effect of freezing is the dehydration of bacterial cells. This creates another stress-high osmolarity-caused by high concentrations of internal solutes [26]. Finally, this injury can lead to cell death.…”