Hary Razafindralambo

By Mohamed Amin Ali, Joël De Coninck and Hary L. Razafindralambo

Wettability is a macroscopic consequence of microscopic phenomena occurring at the fluid-solid interfaces. This functional property is crucial for the formulation of wettable powders in food and non-food sectors. Basically, powder wettability is mostly assessed through the contact angle measurements of solid particles reacting with dispersing media, by either the sessile drop method or the capillary rise technique. Among the most popular bioactive agents nowadays are probiotics and their metabolites, which are receiving a growing interest for their beneficial effects on our ecosystem health. As live functional ingredients, probiotics are mainly available in a powder form that is sensitive to the environmental stress factors during processing and storage steps. It is therefore crucial to understand and control their wettability, regarding their performance, dispersibility, and stability when probiotic particles come into contact with dispersing media and body fluids. The proposal chapter aims to review: (1) the theoretical aspects of powder wettability by considering compact and porous materials; (2) the analytical tools and methodologies of measurement, including sessile drop and capillary rise methods using models Lucas-Washburn equation and Darcy\'s law; and (3) the applications to probiotic powders as functional ingredients in food and agricultural sectors.

Part of the book: New Advances in Powder Technology

By Hary Razafindralambo, Vijayaram Seerengaraj and Holy Rabetafika

Bacillus subtilis is widely recognized as a beneficial and safe microbe for both living species and the environment due to its broad spectrum of bioactive properties. Used for decades as a probiotic, B. subtilis produces diverse bioactive metabolites with antimicrobial, antitumor, antioxidant, and immunomodulatory activities. It forms resilient biofilms, sporulates under stress, promotes plant growth, enhances nutrient uptake, controls pathogens, and contributes to the bioremediation of environmental pollutants such as heavy metals and hydrocarbons. Its long-standing use in food fermentation supports its safety profile and recognition as a safe organism in various applications. Consequently, B. subtilis stands out as a promising candidate for achieving optimal “One Health” outcomes for humans, animals, plants, and their interconnected ecosystems. This chapter provides a biochemical classification of the metabolites and derivatives produced by B. subtilis, highlighting their properties and functions that offer health benefits to both living organisms and the environment.

Part of the book: Bacillus subtilis