Exopolysaccharides produced by lactic acid bacteria are a diverse group of polysaccharides produced by many species. They vary widely in their molecular, compositional, and structural characteristics, including mechanisms of synthesis. The physiochemical properties of these polymers mean that they can be exploited for the sensorial and textural enhancement of a variety of food and beverage products. Traditionally, lactic acid bacteria exopolysaccharides have an important role in fermented dairy products and more recently are being applied for the improvement of bakery products. The health benefits that are continually being associated with these polysaccharides enable the development of dual function, added-value, and clean-label products. To fully exploit and understand the functionality of these exopolysaccharides, their isolation, purification, and thorough characterization are of great importance. This review considers each of the above factors and presents the current knowledge on the importance of lactic acid bacteria exopolysaccharides in the food and beverage industry.
2 April 2019 in Comprehensive Reviews in Food Science and Food Safety
Acetic acid bacteria (AAB) have, for centuries, been important microorganisms in the production of fermented foods and beverages such as vinegar, kombucha, (water) kefir, and lambic beer. Their unique form of metabolism, known as “oxidative” fermentation, mediates the transformation of a variety of substrates into products, which are of importance in the food and beverage industry and beyond; the most well‐known of which is the oxidation of ethanol into acetic acid. Here, a comprehensive review of the physiology of AAB is presented, with particular emphasis on their importance in the production of vinegar and fermented beverages. In addition, particular reference is addressed toward Gluconobacter oxydans due to its biotechnological applications, such as its role in vitamin C production. The production of vinegar and fermented beverages in which AAB play an important role is discussed, followed by an examination of the literature relating to the health benefits associated with consumption of these products. AAB hold great promise for future exploitation, both due to increased consumer demand for traditional fermented beverages such as kombucha, and for the development of new types of products. Further studies on the health benefits related to the consumption of these fermented products and guidelines on assessing the safety of AAB for use as microbial food cultures (starter cultures) are, however, necessary in order to take full advantage of this important group of microorganisms.
The increasing prevalence of coeliac disease (CD) and gluten-related disorders has led to increasing consumer demand for gluten-free products with quality characteristics similar to wheat bread. The replacement of gluten in cereal-based products remains a challenge for scientists, due to its unique role in network formation, which entraps air bubbles. When gluten is removed from a flour, starch is the main component left. Starch is used as gelling, thickening, adhesion, moisture-retention, stabilizing, film forming, texturizing and anti-staling ingredient. The extent of these properties varies depending on the starch source. The starches can additionally be modified increasing or decreasing certain properties of the starch, depending on the application. Starch plays an important role in the formulation of bakery products and has an even more important role in gluten-free products. In gluten-free products, starch is incorporated into the food formulation to improve baking characteristics such as the specific volume, colour and crumb structure and texture. This review covers a number of topics relating to starch; including; an overview of common and lesser researched starches; chemical composition; morphology; digestibility; functionality and methods of modification. The emphasis of this review is on starch and its properties with respect to the quality of gluten-free products.