# Encapsulated Probiotics: Potential Techniques and Coating Materials for Non-Dairy Food Applications
## 1 Introduction  
The growing awareness among consumers regarding healthy lifestyles has increased the demand for food that could provide additional specific health benefits beyond nutrition. Functional food is one of the leading trends in today's food industry. The term \"functional food\" refers to foods containing (either present naturally or added by manufacturers) ingredients or bioactive compounds that provide extra health benefits over its adequate nutritional effects, which can beneficially affect one or more physiological mechanisms in the body, resulting in an enhancement in health and reduction in risk for disease, in the amount consumed in a diet [1]. For example, probiotics are one of the dominant groups of functional foods [2]. Probiotics, from the Greek word, \"for life\", are defined as \"live microorganisms that, when administered in adequate amounts, confer a health benefit to the host\" by a joint United Nations Food and Agricultural Organization/World Health Organization working group in 2001 and The International Scientific Association for Probiotics and Prebiotics (IS-APP). Probiotics have also been considered functional foods due to their health-promoting abilities [3]. Among probiotic strains in use today, strains from genera of _Lactobacillus_ andBifidobacterium_ are the most frequently used. In addition, other non-pathogenic microorganisms that occur within the host gut or tissues have also been developed as probiotics. These include strains from genera _Propionibacterium_, _Pediococcus_, _Bacteroides_, _Basillus_, _Streptococcus_, _Escherichia_, _Enterococcus_, and _Saccharomyces_. Lately, _Faecalibacterium prausnitzii_, _Akkermansia muciniphila_, and _Eubacterium hallii_ have also been identified as potential next-generation probiotics with promising health-promoting functionalities [1; 4]. By regulating the natural balance of gut bacteria in the human gastrointestinal tract, probiotics have been shown to promote a wide range of health benefits such as improving intestinal health, improving lactose digestion, enhancing the host's immune response, reducing serum cholesterol, diarrhea diseases, and inflammatory bowel disease, counter-acting allergies, and lowering the risk of certain cancers [5]. For a potential probiotic strain to exert therapeutic effects on the host, the viability of probiotics in food should be at least 6 to 7 log CFU/mL (or CFU/g) when reaching the small intestine and colon. In this regard, the viability of at least 8 to 9 log CFU/mL (or CFU/g) of probiotics in food before ingestion is necessary [3; 6]. Probiotics must be stable throughout the digestive tract and able to adhere to human epithelial cells when they reach the intestine. However, the survival of probiotics is greatly affected by the harsh conditions of the gastrointestinal tract, including the acidic pH of the gastric environment and bile acids (a loss of around 2 log CFU/mL or CFU/g during digestion) [7]. Several intrinsic (e.g., pH, water activity, molecular oxygen, the composition of the food, food additives added, and oxidation-reduction potential) and extrinsic factors (e.g., temperature, relative humidity, and gas composition) have also been observed to negatively affect the viability and stability of probiotics during food preparation and food processing, as well as over a prolonged storage period [5; 7; 8]. Traditionally, dairy products have been recognized as the best carriers of probiotics. Current probiotics have been formulated into numerous dairy products, such as fermented milk, yogurt, cheese, and ice cream. However, consumers' preferences today lie more with non-dairy-based probiotic products because of the ongoing trend of vegetarianism and awareness of drawbacks associated with the intake of dairy products, such as lactose intolerance, high cholesterol content, and milk protein allergy [2; 9].