The Triple Jags of Dietary Fibers in Cereals: How Biotechnology Is Longing for High FiberGrains

Abstract

Cereals represent an important source of beneficial compounds for human health, such as macro- and micronutrients, vitamins, and bioactive molecules. Generally, the consumption of whole-grain products is associated with significant health benefits, due to the elevated amount of dietary fiber (DF). However, the consumption of whole-grain foods is still modest compared to more refined products. In this sense, it is worth focusing on the increase of DF fractions inside the inner compartment of the seed, the endosperm, which represents the main part of the derived flour. The main components of the grain fiber are arabinoxylan (AX), β-glucan (βG), and resistant starch (RS). These three components are differently distributed in grains, however, all of them are represented in the endosperm. AX and βG, classified as non-starch polysaccharides (NSP), are in cell walls, whereas, RS is in the endosperm, being a starch fraction. As the chemical structure of DFs influences their digestibility, the identification of key actors involved in their metabolism can pave the way to improve their function in human health. Here, we reviewed the main achievements of plant biotechnologies in DFs manipulation in cereals, highlighting new genetic targets to be exploited, and main issues to face to increase the potential of cereals in fighting malnutrition.

Increasing the Versatility of Durum Wheat through Modifications of Protein and Starch Composition and Grain Hardness

“…The synthesis of amylose and amylopectin is carried out by different classes of enzymes. In particular, a granule-bound starch synthase (GBSSI) is involved in amylose synthesis, whereas amylopectin is produced by the concerted action of different starch synthases (SSI, SSII, SSIII), starch-branching enzymes (SBEI, SBEIIa and SBEIIb) and starch-debranching enzymes of isoamylase- and limit dextrinase-type (ISA and LD) [ 52 , 53 , 54 ]. The manipulation of starch composition has been the target of many researchers, thanks to the identification of mutants involved in the synthesis of the amylose and amylopectin and the availability of genomic resources and of new high-throughput technologies ( Figure 2 ).…”

Characterization of Fresh Pasta Made of Common and High-Amylose Wheat Flour Mixtures

“…Increasing the amount of amylose in wheat grain is a target of breeding programs as it improves the nutritional profile of wheat by increasing its fraction of resistant starch (RS), which is undigested in the small intestine by amylases and fermented only by intestinal microbiota; this improves glucose metabolism after a meal [ 1 ]. Starch is known to be a mixture of two glucan homopolymers, amylose and amylopectin, that have the same backbone but differ in the degree of polymerization and ramification [ 2 ]. Amylose is smaller and mainly linear compared to amylopectin, which is highly branched.…”

Phytochemical Profiling and Untargeted Metabolite Fingerprinting of the MEDWHEALTH Wheat, Barley and Lentil Wholemeal Flours

“…Svevo-HA was used for the beneficial effects of amylose and resistant starch on health. Indeed, a positive correlation was found between the amylose content in wheat grain and the amount of resistant starch (RS) in the derived foods [ 11 , 12 ]. Although not digested in the stomach, RS plays health benefits similar to those of dietary fibre by reducing the glycaemic index and heart disease, improving prebiotic activity and preventing colon cancer, but, unlike other fibres, RS does not affect the flavour or colour of food [ 13 ].…”