Table_2_The Triple Jags of Dietary Fibers in Cereals: How Biotechnology Is Longing for High FiberGrains.docx

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.

谷物是人类健康中益处显著的化合物的重要来源，包括宏量及微量营养素、维生素和生物活性分子。通常，全谷物产品的消费与显著的健康益处相关联，这得益于其中丰富的膳食纤维（DF）。然而，与更精制的食品相比，全谷物食品的消费量仍然有限。在此意义上，关注种子内腔——即胚乳——中DF含量的增加具有重要意义，因为胚乳是衍生面粉的主要部分。谷物纤维的主要成分包括阿拉伯木聚糖（AX）、β-葡聚糖（βG）和抗性淀粉（RS）。这三种成分在谷物中的分布各不相同，但它们都存在于胚乳中。AX和βG，作为非淀粉多糖（NSP），存在于细胞壁中，而RS则存在于胚乳中，是一种淀粉组分。由于膳食纤维的化学结构影响其可消化性，识别参与其代谢的关键作用者，可以为其在人类健康中的功能改善开辟道路。在此，我们回顾了植物生物技术在谷物中DFs调控的主要成就，突出了可被利用的新遗传靶点，以及面临的主要问题，以提高谷物在对抗营养不良方面的潜力。