Low glycaemic index foods from wild barley and amylose-only barley lines

Food Hydrocolloids: Structure, Properties, and Applications

Hydrocolloids are extensively used in the food industry for various functions, including gelling, thickening, stabilizing foams, emulsions, and dispersions, as well as facilitating the controlled release of flavor [...].

Beneficial glycaemic effects of high-amylose barley bread compared to wheat bread in type 2 diabetes

BACKGROUND

Cereals foods with a high content of dietary fibres or amylose have potential to lower postprandial glucose levels. Optimisation of cereal foods may improve management of type 2 diabetes (T2D).

METHODS

We investigated the impact on 4 h postprandial glucose responses given as incremental area under curve (iAUC) of bread made of either 50% RNAi-based (genetically modified) amylose-only barley flour (AmOn) (and 50% wheat flour), 50% hulless barley flour (and 50% wheat flour) or 75% hulless barley (and 25% wheat flour) in subjects with T2D compared with 100% wheat flour bread.

DESIGN

Twenty adults with T2D were randomly allocated to one of four breads at four separate visits. We measured fasting and 4 h postprandial responses of glucose, insulin, glucagon, triacylglycerol (TG), free fatty acids (FFA), glucagon-like peptide-1 (GLP-1) and gastric inhibitory polypeptide (GIP). Mixed model ANOVA was used to examine the differences.

RESULTS

Bread made from 50% AmOn lowered the 4 h postprandial glucose by 34%, 27%, 23% (P < 0.05) compared with 100% wheat, 50% or 75% hulless barley, respectively. Bread made from 75% hulless barley reduced the postprandial glucose response (iAUC) by 11% (P < 0.05) compared to 100% wheat bread. Postprandial insulin responses (iAUC) were reduced for 50% AmOn compared with 100% wheat and 50% hulless barley and for 75% hulless compared to 50% hulless barley bread (P < 0.05). 4 h postprandial glucagon (tAUC) did not differ between the four bread types (P > 0.05). Lower postprandial GIP (iAUC) was observed after all barley breads compared to 100% wheat (P < 0.05), whereas no difference was seen in postprandial GLP-1. Postprandial TG and FFA (tAUC) were difficult to judge due to differences in fasting values.

CONCLUSIONS

Bread made by replacing wheat flour with either 50% high-amylose or 75% hulless barley flour lowered postprandial glucose responses compared to 100% wheat bread indicating a beneficial impact on glucose regulation in T2D subjects. This trial was registered at clinicaltrials.gov as NCT04646746.

Prehistoric Plant Exploitation and Domestication: An Inspiration for the Science of De Novo Domestication in Present Times

De novo domestication is a novel trend in plant genetics, where traits of wild or semi-wild species are changed by the use of modern precision breeding techniques so that they conform to modern cultivation. Out of more than 300,000 wild plant species, only a few were fully domesticated by humans in prehistory. Moreover, out of these few domesticated species, less than 10 species dominate world agricultural production by more than 80% today. Much of this limited diversity of crop exploitation by modern humans was defined early in prehistory at the emergence of sedentary agro-pastoral cultures that limited the number of crops evolving a favorable domestication syndrome. However, modern plant genetics have revealed the roadmaps of genetic changes that led to these domestication traits. Based on such observations, plant scientists are now taking steps towards using modern breeding technologies to explore the potential of de novo domestication of plant species that were neglected in the past. We suggest here that in this process of de novo domestication, the study of Late Paleolithic/Late Archaic and Early Neolithic/Early Formative exploration of wild plants and identification of neglected species can help identify the barriers towards domestication. Modern breeding technologies may then assist us to break these barriers in order to perform de novo domestication to increase the crop species diversity of modern agriculture.

Role, Relevance, and Possibilities of In vitro fermentation models in human dietary, and gut-microbial studies

Dietary studies play a crucial role in determining the health-benefiting effects of most food substances, including prebiotics, probiotics, functional foods, and bioactive compounds. Such studies involve gastrointestinal digestion and colonic fermentation of dietary substances. In colonic fermentation, any digested food is further metabolized in the gut by the residing colonic microbiota, causing a shift in the gut microenvironment and production of various metabolites, such as short-chain fatty acids (SCFA). These diet-induced shifts in the microbial community and metabolite production, which can be assessed through in vitro fermentation models using a donor's fecal microbiota, are well known to impact the health of the host. Although in vivo or animal experiments are the gold standard in dietary studies, recent advancements using different in vitro systems, like artificial colon (ARCOL), mini bioreactor array (MBRA), TNO in vitro model of the colon (TIM), Simulator of the Human Intestinal Microbial Ecosystem (SHIME), M-SHIME, CoMiniGut, and Dynamic Gastrointestinal Simulator (SIMGI) make it easy to study the dietary impact in terms of the gut microbiota and metabolites. Such a continuous in vitro system can have multiple compartments corresponding to different parts of the colon, i.e., proximal, transverse, and distal colon, making the findings physiologically more significant. Further, post-fermentation samples can be analyzed using metagenomic, metabolomic, qPCR and flow cytometry approaches. Moreover, studies have shown that in vitro results are in accordance with the in vivo findings, supporting their relevance in dietary studies and giving confidence that shifts in metabolites are only due to microbes. This review meticulously describes the recent advancements in various fermentation models and their relevance in dietary studies. This article is protected by copyright. All rights reserved.

Effect of Amylose and Crystallinity Pattern on the Gelatinization Behavior of Cross-Linked Starches

Starches from normal maize (NM), normal potato (NP), waxy maize (WM), and waxy potato (WP) were cross-linked with seven different concentrations (0.01, 0.05, 0.1, 0.5, 1, 5, 10%) of sodium trimetaphosphate and sodium tripolyphosphate. The use of low-amylose WM and WP as well as A-crystalline maize and B-crystalline potato starches can determine the influence of the amylose content and crystallinity pattern on the cross-linking of starches. The results showed that the viscosity of the cross-linked starch (CLs) first increased and then deceased, and finally no viscosity was detected; WM showed no viscosity at 5% and NP at 1%. In addition, the viscosity of NM first increased and then became undetectable at 0.5%. Strikingly, the WP developed viscosity even at a 10% reagent level (RL), and it developed the highest viscosity of all samples at 1%. The starch-iodine method was a facile and high-performance method for the characterization of the cross-linking degree (CL%), having been applied to normal starches, because the increase in the CL% resulted in a decrease of iodine-complexed amylose and blue intensity. In this study, the starch-iodine method was extended to waxy starches, which stained brown with iodine, and the brown intensity decreased with the increase of the CL%. Moreover, the CL% and RL showed a linear-log relationship.

High Amylose-Based Bio Composites: Structures, Functions and Applications

As biodegradable and eco-friendly bio-resources, polysaccharides from a wide range of sources show steadily increasing interest. The increasing fossil-based production of materials are heavily associated with environmental and climate concerns, these biopolymers are addressing such concerns in important areas such as food and biomedical applications. Among polysaccharides, high amylose starch (HAS) has made major progress to marketable products due to its unique properties and enhanced nutritional values in food applications. While high amylose-maize, wheat, barley and potato are commercially available, HAS variants of other crops have been developed recently and is expected to be commercially available in the near future. This review edifies various forms and processing techniques used to produce HAS-based polymers and composites addressing their favorable properties as compared to normal starch. Low toxic and high compatibility natural plasticizers are of great concern in the processing of HAS. Further emphasis, is also given to some essential film properties such as mechanical and barrier properties for HAS-based materials. The functionality of HAS-based functionality can be improved by using different fillers as well as by modulating the inherent structures of HAS. We also identify specific opportunities for HAS-based food and biomedical fabrications aiming to produce cheaper, better, and more eco-friendly materials. We acknowledge that a multidisciplinary approach is required to achieve further improvement of HAS-based products providing entirely new types of sustainable materials.

Barley: a potential cereal for producing healthy and functional foods

Barley is the fourth largest cereal crop in the world. It is mainly used for feeding, beer production and food. Barley is receiving more attention from both agricultural and food scientists because of its special chemical composition and health benefits. In comparison with other cereal crops, including wheat, rice and maize, barley grains are rich in dietary fiber (such as β-glucan) and tocols, which are beneficial to human health. It is well proved that diets rich in those chemicals can provide protection against hypertension, cardiovascular disease, and diabetes. Barley has been widely recognized to be great potential as a healthy or functional food. In this review, we present the information about the studies on physical structure of barley grain and the distribution of main chemical components, nutrient and functional composition of barley grain and their health benefits, and the approaches of improving and utilizing the nutrient and functional chemicals in barley grain. With the development of processing technologies, functional components in barley grains, especially β-glucan, can be efficiently extracted and concentrated. Moreover, nutrient and functional components in barley grains can be efficiently improved by precise breeding and agronomic approaches. The review highlights the great potential of barley used as healthy and functional foods, and may be instructive for better utilization of barley in food processing.

Tritordeum as an Innovative Alternative to Wheat: A Comparative Digestion Study on Bread

Tritordeum results from the crossbreeding of a wild barley (Hordeum chilense) species with durum wheat (Triticum turgidum spp. turgidum). This hexaploid crop exhibits agronomic and rheological characteristics like soft wheat, resulting in an innovative raw material to produce baked goods. We applied a gel-based proteomic approach on refined flours to evaluate protein expression differences among two widespread tritordeum cultivars (Aucan and Bulel) taking as the reference semolina and flour derived from a durum and a soft wheat cvs, respectively. The products of in vitro digestion of model breads were analyzed to compare bio-accessibility of nutrients and mapping tritordeum bread resistant peptides. Significant differences among the protein profiles of the four flours were highlighted by electrophoresis. The amino acid bio-accessibility and the reducing sugars of tritordeum and wheat breads were comparable. Tritordeum cvs had about 15% higher alpha-amino nitrogen released at the end of the duodenal simulated digestion than soft wheat (p < 0.05). Bulel tritordeum flour, bread and digested bread had about 55% less R5-epitopes compared to the soft wheat. Differences in protein expression found between the two tritordeum cvs reflected in diverse digestion products and allergenic and celiacogenic potential of the duodenal peptides. Proteomic studies of a larger number of tritordeum cvs may be successful in selecting those with good agronomical performances and nutritional advantages.

Starch/Poly(glycerol-adipate) Nanocomposites: A Novel Oral Drug Delivery Device

Biocompatible and bio-based materials are an appealing resource for the pharmaceutical industry. Poly(glycerol-adipate) (PGA) is a biocompatible and biodegradable polymer that can be used to produce self-assembled nanoparticles (NPs) able to encapsulate active ingredients, with encouraging perspectives for drug delivery purposes. Starch is a versatile, inexpensive, and abundant polysaccharide that can be effectively applied as a bio-scaffold for other molecules in order to enrich it with new appealing properties. In this work, the combination of PGA NPs and starch films proved to be a suitable biopolymeric matrix carrier for the controlled release preparation of hydrophobic drugs. Dynamic Light Scattering (DLS) was used to determine the size of drug-loaded PGA NPs, while the improvement of the apparent drug water solubility was assessed by UV-vis spectroscopy. In vitro biological assays were performed against cancer cell lines and bacteria strains to confirm that drug-loaded PGA NPs maintained the effective activity of the therapeutic agents. Dye-conjugated PGA was then exploited to track the NP release profile during the starch/PGA nanocomposite film digestion, which was assessed using digestion models mimicking physiological conditions. The collected data provide a clear indication of the suitability of our biodegradable carrier system for oral drug delivery.

Wxlv, the Ancestral Allele of Rice Waxy Gene

In rice grains, the Waxy (Wx) gene is responsible for the synthesis of amylose, the most important determinant for eating and cooking quality. The effects of several Wx alleles on amylose content and the taste of cooked rice have been elucidated. However, the relationship between artificial selection and the evolution of various Wx alleles as well as their distribution remain unclear. Here we report the identification of an ancestral allele, Wx^lv, which dramatically affects the mouthfeel of rice grains by modulating the size of amylose molecules. We demonstrated that Wx^lv originated directly from wild rice, and the three major Wx alleles in cultivated rice (Wx^b, Wx^a, and Wxⁱⁿ) differentiated after the substitution of one base pair at the functional sites. These data indicate that the Wx^lv allele played an important role in artificial selection and domestication. The findings also shed light on the evolution of various Wx alleles, which have greatly contributed to improving the eating and cooking quality of rice.