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Food security is one of the biggest concerns in food processing. In recent decades, the effects of contaminants in food crops are currently compromising food security and human health. Food contamination can be microbiological, chemical and physical. It can occur on different steps of food processing, such as transport, storage and packaging of raw or processed food, as well as during heating processes. Therefore, substances including the additives can help to maintain the food security during food processing until it reaches the consumers. They can provide food preservation, maintaining freshness and preventing bacterial contamination, among many others. The additives from natural sources have been receiving more attention from food manufacturers when compared to the synthetic ones, due to their higher quality and safety. An example of natural additives are biosurfactants, which are derived from microorganisms. Interests in the use of biosurfactants have been increasing in the food market, as a result of their capacity to replace synthetic additives in the food industry. The objective of this chapter is to present the main microbial biosurfactants used to avoid contamination during food processing. We briefly discuss their potential applications as food preservatives, presenting antimicrobial, antioxidant and antibiofilm activities against food pathogens.

Microbial exopolysaccharides (EPS) are an abundant and important group of compounds that can be secreted by bacteria, fungi and algae. The biotechnological production of these substances represents a faster alternative when compared to chemical and plant-derived production with the possibility of using industrial wastes as substrates, a feasible strategy after a comprehensive study of factors that may affect the synthesis by the chosen microorganism and desirable final product. Another possible difficulty could be the extraction and purification methods, a crucial part of the production of microbial polysaccharides, since different methods should be adopted. In this sense, this review aims to present the biotechnological production of microbial exopolysaccharides, exploring the production steps, optimization processes and current applications of these relevant bioproducts.

Nowadays, food, cosmetic, environmental and pharmaceutical fields are searching for alternative processes to obtain their major products in a more sustainable way. This fact is related to the increasing demand from the consumer market for natural products to substitute synthetic additives. Industrial biotechnology appears as a promising area for this purpose; however, the success of its application is highly dependent of the availability of a suitable microorganism. To overcome this drawback, the isolation of microorganisms from diverse sources, including fermented food, adverse environments, contaminated samples or agro-industrial wastes is an important approach that can provide a more adaptable strain able to be used as biocatalyst and that exhibit resistance to industrial conditions and high yields/productivities in biotechnological production of natural compounds. The aim of this review is to provide a solid set of information on the state of the art of isolation and screening studies for obtaining novel biocatalysts able to produce natural compounds, focusing in aromas, biosurfactants, polysaccharides and microbial oils.

Products that bear the label "natural" have gained more attention in the marketplace. In this approach, the production of aroma compounds through biotransformation or bioconversion has been receiving more incentives in economic and research fields. Among the substrates used in these processes, terpenes can be highlighted for their versatility and low cost; some examples are limonene, α-pinene, and β-pinene. This work focused on the biotransformation of the two bicyclic monoterpenes, α-pinene and β-pinene; the use of different biocatalysts; the products obtained; and the conditions employed in the process.