Barley

Dietary Fibre from Whole Grains and Their Benefits on Metabolic Health

“…Barley is one of the earliest cultivated cereals and exists in hulled and hulless varieties. Hulled barley can be dehulled after harvest prior to processing [ 7 ]. However, the hull from barley is not that easy to remove, as it is ‘cemented’ to the outer layer of the kernel or caryopsis, i.e., the pericarp [ 43 ].…”

“…However, the hull from barley is not that easy to remove, as it is ‘cemented’ to the outer layer of the kernel or caryopsis, i.e., the pericarp [ 43 ]. In both hulled and hulless types, the caryopsis is composed of the pericarp, testa (seed coat), aleurone layer, endosperm, and embryo [ 7 ]. Oats, on the other hand, is also a hulled cereal, but its hull is relatively easy to remove.…”

“…β-glucan and AX are typically present as 70 to 20% of the total dietary fibre content in these cereals. Cereal β-glucan is composed of cellotriosyl and cellotetraosyl units linked through β-1-3 linkages ( Figure 3 ) [ 7 ]. The presence of such β-1-3 linkages leads to bends in the polymer chain structure, allowing water to get in between the chains [ 7 ].…”

“…Cereal β-glucan is composed of cellotriosyl and cellotetraosyl units linked through β-1-3 linkages ( Figure 3 ) [ 7 ]. The presence of such β-1-3 linkages leads to bends in the polymer chain structure, allowing water to get in between the chains [ 7 ]. This explains the higher solubility of β-glucan as compared to cellulose, a structurally related polymer built exclusively of β-1-4-linked d -glucose units [ 67 ].…”

“…Although during this process, the most functional part of a wheat kernel may be purified in the fine white flour to achieve the best quality end product, from a nutritional point of view, the refining process removes vital nutrients, dietary fibre and other phytochemicals from the other grain parts. As a result, the resulting refined products are of lower nutritional quality than the original whole grain products [ 7 ]. Therefore, the consumption of whole grain products, that have inherently a higher dietary fibre content than refined grain products and usually have a dietary fibre profile with a good balance between soluble and insoluble fibre components [ 8 ], undoubtedly can make a big difference in alleviation of risk on NCDs.…”