18 - Probiotic functional foods

Abstract

Traditionally probiotics have been added into fermented dairy products. This is due to the fact that dairy-based matrices are good carriers for probiotic bacteria. Currently, probiotics are available for consumers in an increasing variety of foods, especially non-dairy applications. All food matrices have unique characteristics that can either support the viability of probiotics or be detrimental to it. In food applications the factors that need to be considered include raw materials and additives, the process itself, final product and its properties, storage conditions and shelf-life. In fermented milks, several factors such as pH, organic acids, starter microbes, and potential presence of flavouring compounds and various additives (including preservatives) affect the viability of probiotic bacteria. Processing, storage conditions and shelf-lives of fermented milk products vary considerably and all these factors have an impact on the viability and stability of probiotics added into the product. Similarly to dairy-based matrices, cereal-based food matrices may be quite good supporters of probiotic viability and stability. Milk and many cereals have been shown to contain components (e.g. protein, fat, or fibre) that can protect the viability of added microbes. In shelf-stable beverages one of the most important factors affecting probiotic viability is the pH of the product, where values below 4 are typically detrimental to most probiotic strains. Some vegetable-based probiotic applications exist, although these are few in number compared to fruit-based applications.