Annual Review of Food Science and Technology - Volume 3, 2012

The human intestinal microbiota forms an integral part of normal human physiology, and disturbances of the normal gut microbiology have been implicated in many health and disease issues. Because newborns are essentially sterile, their microbiota must establish and develop from the very first days of life. The first colonizers play an important role in the development of the ecosystem and may impact the long-term composition and activity of the microbiota. These first settlers obviously develop and proliferate dependent on host characteristics and diet, but other factors can also significantly contribute to this vital biological process. Considering the importance of the microbiota for the human immune, metabolic, and neurological systems, it is important to understand the dynamics and driving determinants of this development. This review gives a global overview of our current understanding of the different factors impacting the intestinal microbiology in early life.

The majority of the protein in cow's milk is contained in the particles known as casein micelles. This review describes the main structural features of these particles and the different models that have been used to define the interior structures. The reactions of the micelles during processing operations are described in terms of the structural models.

The unique properties of wheat reside primarily in its gluten-forming storage proteins. Their intrinsic viscoelastic behavior is responsible for the characteristics of different wheat-based foods and for the use of wheat gluten proteins in different food products. Wheat-based food processing generally develops and sets the gluten protein network. Heat-induced gluten aggregation proceeds through cross-linking within and between its protein fractions. Prominent reactions include sulfhydryl (SH) oxidation and SH-disulfide (SS) interchange, which lead to SS cross-links. Other covalent bonds are also formed. Gluten functionality can be (bio-) chemically impacted. We focus on bread making, in which gluten proteins contribute to dough properties, bread loaf volume, and structure, and on pasta production, in which gluten proteins generate the desired cooking quality. Furthermore, it is speculated that the structure and texture of soft wheat products are also, at least to some degree, shaped by the heat-induced changes in the gluten protein fraction.

First recognized in 1895, X-ray irradiation soon became a breakthrough diagnostic tool for the dental and medical professions. However, the food industry remained slow to adopt X-ray irradiation as a means for controlling insects and microbial contaminants in food, instead using gamma and electron beam (E-beam) irradiation. However, the reinvention of X-ray machines with increased efficiency, combined with recent developments in legislation and engineering, is now allowing X-ray to actively compete with gamma irradiation and E-beam as a microbial reduction strategy for foods. This review summarizes the historical developments of X-rays and discusses the key technological advances over the past two decades that now have led to the development of several different X-ray irradiators capable of enhancing the safety and shelf life of many heat-sensitive products, including lettuce, spinach, tomatoes, and raw almonds, all of which have been linked to high profile outbreaks of foodborne illness.