In 2012, the world production of starch was 75 million tons. Maize, cassava, wheat and potato are the main botanical origins for starch production with only minor quantities of rice and other starches being produced. These starches are either used by industry as such or following some conversion. When selecting and developing starches for specific purposes, it is important to consider the differences between starches of varying botanical origin. Here, an overview is given of the production, structure, composition, morphology, swelling, gelatinisation, pasting and retrogradation, paste firmness and clarity and freeze–thaw stability of maize, cassava, wheat, potato and rice starches. Differences in properties are largely defined by differences in amylose and amylopectin structures and contents, granular organisation, presence of lipids, proteins and minerals and starch granule size.

Starch-water, gluten-water, and flour-water model systems as well as straight-dough bread were investigated with (1)H NMR relaxometry using free induction decay and Carr-Purcell-Meiboom-Gill pulse sequences. Depending on the degree of interaction between polymers and water, different proton populations could be distinguished. The starch protons in the starch-water model gain mobility owing to amylopectin crystal melting, granule swelling, and amylose leaching, whereas water protons lose mobility due to increased interaction with starch polymers. Heating of the gluten-water sample induces no pronounced changes in proton distributions. Heating changes the proton distributions of the flour-water and starch-water models in a similar way, implying that the changes are primarily attributable to starch gelatinization. Proton distributions of the heated flour-water model system and those of fresh bread crumb are very similar. This allows identifying the different proton populations in bread on the basis of the results from the model systems.

Proteins play a crucial role in determining texture and structure of many food products. Although some animal proteins (such as egg white) have excellent functional and organoleptic properties, unfortunately, they entail a higher production cost and environmental impact than plant proteins. It is rather unfortunate that plant protein functionality is often insufficient because of low solubility in aqueous media. Enzymatic hydrolysis strongly increases solubility of proteins and alters their functional properties. The latter is attributed to 3 major structural changes: a decrease in average molecular mass, a higher availability of hydrophobic regions, and the liberation of ionizable groups. We here review current knowledge on solubility, water-and fat-holding capacity, gelation, foaming, and emulsifying properties of plant protein hydrolysates and discuss how these properties are affected by controlled enzymatic hydrolysis. In many cases, research in this field has been limited to fairly simple set-ups where functionality has been assessed in model systems. To evolve toward a more widely applied industrial use of plant protein hydrolysates, a more thorough understanding of functional properties is required. The structure-function relationship of protein hydrolysates needs to be studied in depth. Finally, test model systems closer to real food processing conditions, and thus to real foods, would be helpful to evaluate whether plant protein hydrolysates could be a viable alternative for other functional protein sources.

In this paper, the current knowledge on properties of starch blends is critically reviewed. Nowadays, chemical modifications are commonly applied to modify starch properties. However, industry calls for alternatives for chemically modified starches to address the consumer's demand for natural food systems. A simple way to impact starch properties is by blending different starches. In some blends, interactions lead to unexpected gelatinization, pasting, gel texture, and retrogradation properties (non‐additive effect), while an additive effect occurs when the behavior of the blend corresponds to what can be expected based on the individual components. Analysis of different studies describing the physicochemical properties of blends brings insight into the role of botanical origin, amylose content, starch‐to‐water ratio, ratio of starches in the blend, etc. in the behavior of the blends. Gelatinization occurs mostly independently in excess water, while at intermediate water content more non‐additive behavior is recorded. Pasting, rheological, and textural properties show primarily non‐additive effects while retrogradation of starch blends occurs mainly in an additive way. Large differences in granule size and swelling power between the starches in a blend lead to uneven moisture distribution during heating of the starch suspension, which results in a different behavior of the blend than what would be expected based on the behavior of the individual starches.

Wheat (Triticum aestivum) contains a previously unknown type of xylanase (EC 3.2.1.8) inhibitor, which is described in the present paper for the first time. Based on its >60% similarity to TLPs (thaumatin-like proteins) and the fact that it contains the Prosite PS00316 thaumatin family signature, it is referred to as TLXI (thaumatin-like xylanase inhibitor). TLXI is a basic (pI> or =9.3 in isoelectric focusing) protein with a molecular mass of approx. 18-kDa (determined by SDS/PAGE) and it occurs in wheat with varying extents of glycosylation. The TLXI gene sequence encodes a 26-amino-acid signal sequence followed by a 151-amino-acid mature protein with a calculated molecular mass of 15.6-kDa and pI of 8.38. The mature TLXI protein was expressed successfully in Pichia pastoris, resulting in a 21-kDa (determined by SDS/PAGE) recombinant protein (rTLXI). Polyclonal antibodies raised against TLXI purified from wheat react with epitopes of rTLXI as well as with those of thaumatin, demonstrating high structural similarity between these three proteins. TLXI has a unique inhibition specificity. It is a non-competitive inhibitor of a number of glycoside hydrolase family 11 xylanases, but it is inactive towards glycoside hydrolase family 10 xylanases. Progress curves show that TLXI is a slow tight-binding inhibitor, with a K(i) of approx. 60-nM. Except for zeamatin, an alpha-amylase/trypsin inhibitor from maize (Zea mays), no other enzyme inhibitor is currently known among the TLPs. TLXI thus represents a novel type of inhibitor within this group of proteins.