Microstructure of Gluten-Free Baked Products

Abstract

Producing high-quality gluten-free products is one of the most challenging issues for the cereal technologist and scientists. Traditionally, most gluten-free products have been produced by replacing wheat flour by alternative flours as well as using some additives to mimic the viscoelastic properties of gluten. Several approaches have been applied to produce gluten-free products similar to that of its gluten-containing counterparts by the use of starches, hydrocolloids, emulsifiers, enzymes, protein, and/or fiber sources. In order to meet the rising demand of celiac patients for high-quality products, sourdough breadmaking technique, as an old biotechnological process, infrared–microwave combination baking, and high hydrostatic pressure (HHP) treatment have also lately been studied as potential methods in gluten-free technology. Up to date, various studies have been conducted on viscoelastic properties of dough/batter, volume, texture, and sensory analysis of gluten-free baked products. Examination of the microstructure of gluten-free products that defines crumb appearance is helpful to provide deeper information about many of the quality attributes of baked products from the knowledge of the ingredients and how they are processed to the cellular structure on which the quality of baked products is established. Food materials are complex systems. The majority of structural elements are below the 100-μm range that makes examining food microstructure a challenging topic for food industry. A large variety of microscopic techniques including light microscopy (LM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), confocal laser-scanning microscopy (CLSM), atomic force microscopy (AFM), magnetic resonance imaging (MRI), nuclear magnetic resonance (NMR) technique, and X-ray microtomography (X-ray μCT) provide a deeper understanding of the microstructure of food products. A number of gluten-free studies have been recently focused on the observation of microstructure to define the quality attributes of dough/batters and/or baked products. The aim of the present chapter is to review the microstructural changes of gluten-free baked products by using various techniques and to understand the influence of different functional ingredients and prospective methods on the microstructure of gluten-free products.