Relationships between protein content, starch molecular structure and grain size in barley

The molecular structure of leaf starch from three cereal crops

Plants produce storage and transient starches in seeds and in leaves, respectively. Understanding molecular fine structure and synthesis of transient starch can help improve plant quality (e.g. by helping breeders produce slowly digested amylopectin, which is beneficial for human nutrition). In the present study, leaf starches from rice, wheat and barley were isolated with cesium chloride gradient centrifugation. Starch fine structure was measured using size-exclusion chromatography and flurophore-assisted carbohydrate electrophoresis. The chain-length distribution (CLD) of amylopectin leaf starch was trimodal in wheat and barley leaf starch. The global peak of leaf starch was at degree of polymerization (DP) 22, and leaf amylopectin containeds more long branches, which are generally considered to hinder starch digestion, suggesting that leaf-specific starch synthesis enzymes could be expressed in the endosperm by genetic modification to produce amylopectin with more long chains, which would be more slowly digested, with advantages to human health. HYPOTHESIS: The biosynthetic processes for leaf starch and storage starch in a given plant species will show significant differences.

Formation of the rosette-like starch with enhanced V-type crystallization via modified solvent-shifting method

This research investigated the effect modified solvent-shifting method on the formation, ordered structure, and morphology of V-type starch. Ionic liquid (IL) dissolution and hot ethanol aqueous incubation in gradient concentrations from 30 % to 80 % (v/v) were applied to optimize the relative crystallinity of V-type starch. The results showed that this new method worked in producing V-type conformation, and higher ethanol concentration tended to yield V-type starch with higher crystallinity and more disk-like shape structure within the ethanol range of 30-50 % (v/v). Notably, the crystalline order of V-type starch reached the maximum with a specific rosette-like morphology under the condition of an ethanol concentration of 50 % (v/v). While the grown crystals organized into small-size flower-like assemblies and this morphology even disappeared accompanied by the V-type crystallization weakening when starch chains co-crystallized with the ethanol concentrations of 60 %-80 % (v/v). The molecular structure analysis indicated no significant correlation between the relative crystallinity of V-type starch and its fine structure. IL served to promote the formation of V-type starch, while it didn't participate in the formation process and could be removed during the washing process. The findings can provide new insights into developing a bottom-up pathway for regulating crystallization and morphology of V-type starch.

Natural starches suitable for 3D printing: Rhizome and seed starch from Millettia speciosa champ, a non-conventional source

The demand for exploring and investigating novel starches for various applications has been high, yet starches abundant in Millettia speciosa Champ (M. speciose) plants have barely been studied. This study aims to investigate the multiscale structure and physicochemical properties, especially good hot-extrusion 3D printability of M. speciosa starches. MRS (rhizome starch of M. speciose) and MSS (seed starch of M. speciose) exhibited different structure comparing with CRS (cassava starch) and WCS (waxy corn starch), such as smaller granules, higher amylose content, weaker short-range ordered structures and lower crystallinity. MSS exhibited a high Rh,AP2 value of 2.50, the thickest lamellar repeating distance of 10.30 nm and the strongest interconnected structure. Correspondingly, MSS displayed low solubility and swelling power, along with the highest onset gelatinization temperature (To), gelatinization enthalpy (ΔH) and resistance starch (RS) content at 75.81 °C, 11.74 J/g and 29.91 %, respectively. Notably, MRS and MSS demonstrated hot-extrusion 3D printability with high printing accuracy(> 93 %) and stability (> 98 %). The significant differences in physicochemical properties between M. speciosa starches are presumed to be influenced by the content of amylose and the length of amylopectin. Starches from M. speciose exhibit potential as thermostable additives and 3D printing materials.

Fine structure of starch biomacromolecules and digestibility: The regulative role of amylose and amylopectin in the digestive hydrolysis of starch in rice

The digestibility of starch in staple foods has rarely been examined at the bio-macromolecular level. This study addresses this by investigating the fine structures of amylose and amylopectin to understand their roles in starch digestibility in cooked white rice. Using the static INFOGEST protocol and oral processing by human volunteers, we assessed the starch digestion characteristics of 13 rice varieties, with amylose and amylopectin chain length distribution being analyzed using size-exclusion chromatography and high-performance anion exchange chromatography, respectively. Kinetic modelling revealed that chewed white rice follows a typical parallel digestion pattern, with rapidly (SF) and slowly digestible starch (SS) being digested simultaneously at distinctly different rates. Amylose content (AC) and amylose weight were significantly and positively correlated with the digestion rate and extent of SS, whereas the digestion rate and extent of SF were closely linked to amylopectin, particularly its short and intermediate chains (degree of polymerization 13-36). Compared to low-amylose rice (AC < 25 %), high-amylose rice exhibited significantly higher SS but with a lower digestion rate, attributed to its higher AC with shorter chains and fewer short to intermediate Ap branches. These findings provide insights into starch structure-digestibility relationships, aiding the development of rice varieties with slower digestion rates.

Highly efficient esterification of waxy maize starch in choline chloride/acetic acid acidic deep eutectic solvent system

In this study, to address the issue of solvent selection in the chemical modification of starch, a method was developed for the efficient esterification of waxy maize starch (WMS) using an acidic deep eutectic solvent composed of choline chloride and acetic acid (CCHAc-ADES). The impact of different mass fractions of CCHAc-ADES on the degree of substitution and reaction efficiency of lauric acid starch esters was explored. It was found that under the conditions of 70 wt% CCHAc-ADES, starch esters with the highest degree of substitution of 0.161 were successfully prepared, achieving an esterification efficiency of 79.63 %. 13C and 1H nuclear magnetic resonance spectroscopy, X-ray diffraction and gel permeation chromatography revealed that CCHAc-ADES acted within the surface voids of WMS particles without seriously damaging the WMS structure, making it a favorable solvent for chemical modification of WMS. By monitoring changes in the morphology, relative crystallinity, particle size, and hydrophobicity of esterified WMS in CCHAc-ADES, the formation mechanism of lauric acid starch esters was inferred, primarily related to the competitive hydrogen bonding of CCHAc-ADES with WMS. The method proposed in this study allows for the preparation of long-chain fatty acid starch esters without the use of any additional chemicals or enzymes, offering significant guidance for the application of deep eutectic solvents in green synthesis.

Effect of wet media milling on starch-quercetin complex: Enhancement of Pickering emulsifying ability and oxidative resistance

This research explored the effect of media milling on complexation of corn starch (CS) and quercetin (QC), interaction mechanism and Pickering emulsifying ability of corn-quercetin (CS-QC) complex. CS-QC with QC/CS ratio of 1:24 had the highest encapsulation efficiency of 76.00 ± 1.30 %. Average volume-mean diameter, average whole molecular size (Rh) and debranchedamylopectinchain length of CS-QC were significantly decreased after milling. Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) spectra confirmed the complexation between CS and QC. Emulsifying capacity and emulsion stability of Pickering emulsion stabilized by 5 % CS-QC complex particles after 120 min milling reached 100.00 % and 100.00. Pickering emulsions stabilized by these complex particles demonstrated superior oxidative stability. These results demonstrated that media milling could be an efficient physical approach to obtain starch-polyphenol complex by enhancing non-covalent interactions, which could not only be used as food-grade Pickering emulsifiers, but also retard lipid oxidation.

Study of starch molecular structure-property relations provides new insight into slowly digested rice development

White rice consumption has been regarded as a potential risk factor for non-communicable diseases including obesity and type 2 diabetes. Thus, increasing attention has been paid to develop slowly digested rices with acceptable palatability. As the most abundant component of rice kernels, the fine molecular structure of starch controls not only the texture & aroma, but also the digestion properties of cooked rice. A large number of studies have been conducted to see what molecular structural features control the digestibility and palatability of cooked rice, which further could be connected to starch biosynthesis to enable rices with targeted functionalities to be chosen in non-empirical ways. Nonetheless, little progress has been made because of improper experimental designs. For example, the effects of starch fine molecular structure on cooked rice digestibility and palatability has been rarely studied within one study, resulting to various digestion results. Even for the same sample, it is hard to obtain consistent conclusions and sometimes, the results/coclusions are even controversy. In this review paper, starch fine molecular structural effects on the texture, aroma and starch digestion properties of cooked white rice were summarized followed by a detailed discussion of the relations between the fine molecular structures of amylopectin and amylose to deduce a more general conclusion of starch molecular structure-cooked rice property relations. It is expected that this review paper could provide useful information in terms of how to develop slowly digested rices with acceptable palatability.

Advances in Extraction, Structure, and Physiochemical Properties of Sorghum Kafirin for Biomaterial Applications: A Review

Kafirin is an endosperm-specific hydrophobic protein found in sorghum grain and the waste by-product from sorghum biorefineries known as sorghum dried distillers' grain with solubles (DDGS). Because of kafirin's poor nutritional profile (negative nitrogen balance, slow digestibility, and lack of some essential amino acids), its direct human use as a food is restricted. Nevertheless, increased focus on biofuel production from sorghum grain has triggered a new wave of research to use sorghum DDGS kafirin as a food-grade protein for biomaterials with diverse applications. These applications result from kafirin's unique chemical nature: high hydrophobicity, evaporation-induced self-assembling capacity, elongated conformation, water insolubility, and low digestibility. Aqueous alcohol mixtures have been widely used for the extraction of kafirin. The composition, structure, extraction methodologies, and physiochemical properties of kafirin, emphasising its biomaterial functionality, are discussed in detail in this review. The literature survey reveals an in-depth understanding of extraction methodologies and their impact on structure functionality, which could assist in formulating materials of kafirin at a commercial scale. Ongoing research continues to explore the potential of kafirin and optimise its utilisation as a functional biomaterial, highlighting its valuable structural and physicochemical properties. Further studies should focus on covering gaps in the research as some of the current structural understanding comes from data on zein protein from maize.

Variations in the effects of extrusion treatments and ferulic acid addition on starch digestibility with different botanical backgrounds

In the current study, the effects of extrusion using a haake rheometer with a twin-roll mixer, with and without FA addition, on the structures and in vitro digestibility of starches from different sources were investigated. After extruding for 15 min at 90 °C with a moisture content of 40 %, no matter FA was added or not, lager Ap molecules were preferentially debranched, while Am with longer CL were depolymerized simultaneously, resulting to reduced averaged molecular size of Ap and shortened Am chains. Of all starches, regardless of their botanical backgrounds, although synergic effects were found between extrusion and FA addition on reducing their relative crystallinity and the ordered structures, distinctly different effects on the in vitro digestibility of these starches have also been observed especially regarding the digestion of starch branches with DP > 10 Particularly, the Am chains with DP 10-1000 was remaining undigested when FA was added. This study provides important information concerning how to adjust starch digestibility into a healthy range through altering the starch structures using extrusion technique with the addition of phytochemicals or not.

The changed multiscale structures of tight nut (Cyperus esculentus) starch decide its modified physicochemical properties: The effects of non-thermal and thermal treatments

Non-thermal dielectric barrier discharge plasma (DBDP) and four thermal treatments, including baking (BT), high pressure cooking (HPC), radio frequency (RF) and microwave (MW) were applied to modify the structural and physicochemical properties of Cyperus esculentus starch (CES). The results showed that the thermal treatments remarkably disordered the crystalline structures of CES through weakening the double-helix conformation of amylopectin, while DBDP caused much more gentle influence on the starch structures than them. Specifically, MW induced the high-frequency displacement of polar molecules and intensive collisions between starch and water molecules, causing the largest stretching and swelling extents of amylopectin, resulting in the highest pasting and rheological viscosity of CES in four thermal treatments. As DBDP did not favor the aggregation of amylopectin chains, the deaggregated starch chains promoted the hydration effects with water molecules, boosting the final pasting viscosity, apparent rheological viscosity, freeze-thaw stability and digestion velocity of CES. Besides, the gelatinization-retrogradation process in the thermal treatments regulated starch digestion velocity and produced type III resistant starch in CES. Conclusively, the modified physicochemical properties of CES resulted from the altered molecular structures of starch by the applied treatments.

Development of a barley reference material for gluten analysis

Celiac disease (CD) can be triggered in susceptible individuals by the consumption of gluten, a complex storage protein mixture present in wheat, rye and barley. There is no specific reference material (RM) available for barley and this leads to inaccurate quantitation of barley gluten in supposedly gluten-free foods. Therefore, the aim was to select representative barley cultivars to establish a new barley RM. The relative protein composition of the 35 barley cultivars averaged 25% albumins and globulins, 11% d-hordeins, 19% C-hordeins, and 45% B/γ-hordeins. The mean gluten and protein content was 7.2 g/100 g and 11.2 g/100 g, respectively. The prolamin/glutelin ratio (1:1) commonly used in ELISAs to calculate the gluten content was found to be inappropriate for barley (1.6 ± 0.6). Eight cultivars suitable as potential RMs were selected to ensure a typical barley protein composition and improve food safety for CD patients.

Sustainable Isolation of Bioactive Compounds and Proteins from Plant-Based Food (and Byproducts)

Plant-based food produces significantly less greenhouse gases, and due to its wealth of bioactive components and/or plant-based protein, it becomes an alternative in a sustainable food system. However, the processing and production of products from plant sources creates byproducts, which can be waste or a source of useful substances that can be reused. The waste produced during the production and processing of food is essentially nutrient- and energy-rich, and it is recognized as an excellent source of secondary raw materials that could be repurposed in the process of manufacturing and preparing food, or as feed for livestock. This review offers an overview of the sources and techniques of the sustainable isolation of bioactive substances and proteins from various sources that might represent waste in the preparation or production of food of plant origin. The aim is to uncover novel approaches to use waste and byproducts from the process of making food to provide this waste food an additional benefit, not forgetting the expectations of the end user, the consumer. For the successful isolation of bioactive ingredients and proteins from food of plant origin, it is crucial to develop more eco-friendly and efficient extraction techniques with a low CO2 footprint while considering the economic aspects.

Climate-Nutrient-Crop Model: Novel Insights into Grain-Based Food Quality

Mineral nutrients spatiotemporally participate in the biosynthesis and accumulation of storage biopolymers, which directly determines the harvested grain yield and quality. Optimizing fertilizer nutrient availability improves the grain yield, but quality aspects are often underestimated. We hypothesize that extensive mineral nutrients have significant effects on the biosynthesis, content, and composition of storage proteins, ultimately determining physicochemical properties and food quality, particularly in the context of climate change. To investigate this, we hierarchized 16 plant mineral nutrients and developed a novel climate-nutrient-crop model to address the fundamental question of the roles of protein and starch in grain-based food quality. Finally, we recommend increasing the added value of mineral nutrients as a socioeconomic strategy to enhance agro-food profitability, promote environmental sustainability, and improve climate resilience.

Variation in quality of grains used in malting and brewing

Cereal grains have been domesticated largely from food grains to feed and malting grains. Barley (Hordeum vulgare L.) remains unparalleled in its success as a primary brewing grain. However, there is renewed interest in "alternative" grains for brewing (and distilling) due to attention being placed on flavor, quality, and health (i.e., gluten issues) aspects that they may offer. This review covers basic and general information on "alternative grains" for malting and brewing, as well as an in-depth look at several major biochemical aspects of these grains including starch, protein, polyphenols, and lipids. These traits are described in terms of their effects on processing and flavor, as well as the prospects for improvement through breeding. These aspects have been studied extensively in barley, but little is known about the functional properties in other crops for malting and brewing. In addition, the complex nature of malting and brewing produces a large number of brewing targets but requires extensive processing, laboratory analysis, and accompanying sensory analysis. However, if a better understanding of the potential of alternative crops that can be used in malting and brewing is needed, then significantly more research is required.

Insights into the Supramolecular Structure and Degradation Mechanisms of Starch from Different Botanical Sources as Affected by Extrusion-based 3D Printing

Extrusion-based 3D printing has emerged as the most versatile additive manufacturing technique for the printing of practically any material. However, 3D printing of functional materials often activates thermo-mechanical degradation, which affects the 3D shape quality. Herein, we describe the structural changes of eight different starch sources (normal or waxy) as a consequence of the temperature of an extrusion-based 3D printing system through in-depth characterization of their molecular and structural changes. The combination of size-exclusion chromatography, small-angle X-ray scattering, X-ray diffraction, dynamic viscoelasticity measurements, and in vitro digestion has offered an extensive picture of the structural and biological transformations of starch varieties. Depending on the 3D printing conditions, either gelatinization was attained ("moderate" condition) or single-amylose helix formation was induced ("extreme" condition). The stiff amylopectin crystallites in starch granules were more susceptible to thermo-mechanical degradation compared to flexible amorphous amylose. The crystalline morphology of the starch varieties varied from B-type crystallinity for the starch 3D printing at the "moderate" condition to a mixture of C- and V-type crystallinity regarding the "extreme" condition. The "extreme" condition reduced the viscoelasticity of 3D-printed starches but increased the starch digestibility rate/extent. In contrast, the "moderate" condition increased the viscoelastic moduli, decreasing the starch digestion rate/extent. This was more considerable mainly regarding the waxy starch varieties. Finally, normal starch varieties presented a well-defined shape fidelity, being able to form a stable structure, whereas waxy starches exhibited a non-well-defined structure and were not able to maintain their integrity after printing. The results of this research allow us to monitor the degradability of a variety of starch cultivars to create starch-based 3D structures, in which the local structure can be controlled based on the 3D printing parameters.

Adaptability of high-protein barley genotypes under the conditions of the Volga-Vyatka region

Background. Barley grain is unique raw material of versatile uses. More than 60% of the grain produced In the Volga-Vyatka region goes directly to fodder production purposes. One of the urgent tasks is to develop high-yielding cultivars with good grain quality, thus reducing protein deficiency in farm animal feeds and meeting the need for fodder grain that increases every year. Its successful solution requires a search for new high-yielding and high-protein source genotypes adapted to the conditions of the Volga-Vyatka region and their involvement in the breeding process.

Materials and methods. Experimental work was carried out in 2018–2020 at the Federal Agricultural Research Center of the North-East named N.V. Rudnitsky, Kirov. Protein content in grain, yield, resistance to lodging, and duration of the growing season of 31 barley accessions were assessed. The barley collection was studied according to the International COMECON List of Descriptors for the Genus Hordeum L. and Methodological Guidelines. Protein content was measured using a universal rapid analyzer (INFRAMATIC 8620).

Results and conclusions. Protein content had a strong correlation with Selyaninov’s hydrothermal coefficient in the interphase period from ear emergence to maturity (r = 0.85); the sum of effective temperatures during the entire growing season (r = 0.75); and precipitation in the period from seedling emergence to maturity (r = 0.67). Traits of breeding value (yield, lodging resistance, environmental plasticity, and stability) were observed in the following accessions: k-30574 (‘Filippa’, Sweden), k-30256 (‘Rodos’, Poland), ya-52 (‘Crusades’, Great Britain), k-35415 (NCL 95098, Argentina), k-30892 (‘Naran’, Russia), k-15619 (‘Polyarny 14’, Russia), ya-4 (752A, Switzerland), k-30349 (Landrace, Peru), k-5983 (Local, Afghanistan), k-3506 (Local, India), k-2929 (Local, China), k-2930 (Local, China), and k-5210 (‘Makbo’, Australia). 

Effect of Genotype and Environment on Food-Related Traits of Organic Winter Naked Barleys

This study aimed to understand how genetics and environment influence organic winter naked barley composition and functionality, and to identify traits that might effectively categorize basic physicochemical functionality of food barley. Across three years, two locations, and 15 genotypes, genotype significantly influenced all 10 food-related traits and was the dominant influence for three. Location significantly influenced eight traits and was dominant for three. Year significantly influenced all traits but was dominant only for one. Of the interactions location * year was the most influential and was the dominant effect for two traits. For all interaction terms where genotype was a component, the effect sizes were either small or non-significant suggesting that even with low leverage traits there is the potential for genetic gain by observing trait rankings across environments. Principal component analysis identified six traits that could serve to categorize basic physicochemical functionality of food barley. These were grain protein content, beta-glucan content, flour-water batter flow, water solvent retention capacity, time to peak viscosity of cooked flour, and hardness of cooked intact grains.

Dimension Reduction of Digital Image Descriptors in Neural Identification of Damaged Malting Barley Grains

The paper covers the problem of determination of defects and contamination in malting barley grains. The analysis of the problem indicated that although several attempts have been made, there are still no effective methods of identification of the quality of barley grains, such as the use of information technology, including intelligent sensors (currently, quality assessment of grain is performed manually). The aim of the study was the construction of a reduced set of the most important graphic descriptors from machine-collected digital images, important in the process of neural evaluation of the quality of BOJOS variety malting barley. Grains were sorted into three size fractions and seed images were collected. As a large number of graphic descriptors implied difficulties in the development and operation of neural classifiers, a PCA (Principal Component Analysis) statistical method of reducing empirical data contained in the analyzed set was applied. The grain quality expressed by an optimal set of transformed descriptors was modelled using artificial neural networks (ANN). The input layer consisted of eight neurons with a linear Postsynaptic Function (PSP) and a linear activation function. The one hidden layer was composed of sigmoid neurons having a linear PSP function and a logistic activation function. One sigmoid neuron was the output of the network. The results obtained show that neural identification of digital images with application of Principal Component Analysis (PCA) combined with neural classification is an effective tool supporting the process of rapid and reliable quality assessment of BOJOS malting barley grains.

Evaluation and Multivariate Analysis of Cowpea [Vigna unguiculata (L.) Walp] Germplasm for Selected Nutrients—Mining for Nutri-Dense Accessions

A total of 120 highly diverse cowpea [Vigna unguiculata (L.) Walp] genotypes, including indigenous and exotic lines, were evaluated for different biochemical traits using AOAC official methods of analysis and other standard methods. The results exhibited wide variability in the content of proteins (ranging from 19.4 to 27.9%), starch (from 27.5 to 42.7 g 100 g−1), amylose (from 9.65 to 21.7 g 100 g−1), TDF (from 13.7 to 21.1 g 100 g−1), and TSS (from 1.30 to 8.73 g 100 g−1). The concentration of anti-nutritional compounds like phenols and phytic acid ranged from 0.026 to 0.832 g 100 g−1 and 0.690 to 1.88 g 100 g−1, respectively. The correlation coefficient between the traits was calculated to understand the inter-trait relationship. Multivariate analysis (PCA and HCA) was performed to identify the major traits contributing to variability and group accessions with a similar profile. The first three principal components, i.e., PC1, PC2, and PC3, contributed to 62.7% of the variation, where maximum loadings were from starch, followed by protein, phytic acid, and dietary fiber. HCA formed six distinct clusters at a squared Euclidean distance of 5. Accessions in cluster I had high TDF and low TSS content, while cluster II was characterized by low amylose content. Accessions in cluster III had high starch, low protein, and phytic acid, whereas accessions in cluster IV contained high TSS, phenol, and low phytic acid. Cluster V was characterized by high protein, phytic acid, TSS, and phenol content and low starch content, and cluster VI had a high amount of amylose and low phenol content. Some nutri-dense accessions were identified from the above-mentioned clusters, such as EC170579 and EC201086 with high protein (&gt;27%), TSS, amylose, and TDF content. These compositions are promising to provide practical support for developing high-value food and feed varieties using effective breeding strategies with a higher economic value.

Preparation of Natural Food-Grade Core-Shell Starch/Zein Microparticles by Antisolvent Exchange and Transglutaminase Crosslinking for Reduced Digestion of Starch

The purpose of this study was to slow down the digestibility of starch granules by encapsulating it in zein shells. Drop of the preformed swollen corn starch (CS) granule suspension into thermal-treated zein ethanolic solution enables antisolvent precipitation of thermal-treated zein on the surface of the preformed swollen CS granules, leading to the formation of core-shell starch/zein microparticles. Confocal laser scanning microscopy images showed that the preformed swollen CS granules were coated by thermal-treated zein shells with a thickness of 0.48–0.95 μm. The volume average particle diameter of core-shell starch/zein microparticles was 14.70 μm and reached 18.59–30.98 μm after crosslinking by transglutaminase. The results of X-ray diffraction and Fourier transform infrared spectroscopy demonstrated that an interaction occurred between the preformed swollen CS granules and the thermal-treated zein. The results for thermodynamic characteristics, pasting properties, and swelling power indicated that the compact network structure of core-shell starch/zein microparticles crosslinked by transglutaminase could improve starch granule thermal stability and resistance to shearing forces. Compared to native CS, the peak gelatinization temperatures of core-shell starch/zein microparticles increased significantly (p < 0.05), with a maximum value of 76.64°C. The breakdown values and the swelling power at 95°C of core-shell starch/zein microparticles significantly (p < 0.05) decreased by 52.83–85.66% and 0.11–0.28%, respectively. The in vitro digestibility test showed that the contents of slowly digestible starch and resistant starch in the core-shell starch/zein microparticles increased to ∼42.66 and ∼34.75%, respectively, compared to those of native CS (9.56 and 2.48%, respectively). Our research supports the application of food-grade core-shell starch/zein microparticles to formulate low-digestibility food products.

Multi-scale structure of A- and B-type granules of normal and waxy hull-less barley starch

The multi-scale structure of combined (A- and B- type granules), A-type, and B-type granules from normal (NHB) and waxy hull-less barley (WHB) starch was studied, including crystalline structure, molecular branching, nanostructural and fractal characteristics. Particle size distribution was applied to determine the separation purity (>95%), and micrography was used to distinguish between the A-type and B-type granules. Lacking amylose, WHB had higher relative crystallinity, gelatinization temperature, enthalpy, level of scattering intensity and uniformity of orientation of double helices than NHB starch. Generally, B-type granules had higher gelatinization temperature, lower enthalpy, greater relative crystallinity, higher ratio of crystalline to amorphous region, more fa chains in amylopectin, and thicker semi-crystalline lamellae than A-type and combined granules. The results showed that the multi-scale structure of A-type and B-type granules differed greatly, and the characteristics of combined granules were not the same as those of its two constituent granule fractions.

Mutual interactions between α‑amylase and amyloglucosidase on the digestion of starch with distinct chain-length distributions at fully gelatinized state

Amyloglucosidase (AMG) and α-amylase (AMY) are involved in the human small intestine for starch digestion, whereas their mutual interactions with starch molecules of distinct structures are still unknown. In current...

Mashing performance as a function of malt particle size in beer production

Significant innovations have occurred over the past 50 years in the malting and brewing industries, focused on optimization of the beer mashing, boiling and fermentation processes. One of the challenges faced in beer brewing has been in the malting process to obtain the desired malt and wort quality to produce high-quality beer products. The hydrolytic enzymes produced during grain germination are mostly entrapped inside the cellular matrices of the grain. The intra-grain diffusion of enzymes for in-situ hydrolysis, as well as diffusion of enzymes to wort, depends upon the malt size and malt size fractions obtained after milling. This review investigates the relationship between varying barley grain particle size distribution and the efficiency of the malting and mashing processes. Recommended ideal particle size of barley grain before and after milling are proposed based on the review of existing literature. Each brewing batch of grains with a proportion of >80% plump grains (>2.5 mm in size) is suggested to be the optimal size before milling, whereas the optimum grain particle size after milling ranged between 0.25 and 0.5 mm. The current review will summarize the theoretical aspects for malt milling and the particle size characteristics for optimizing the brewing process.

Microwave treatment alters the fine molecular structure of waxy hull-less barley starch

Waxy hull-less barley kernels and their isolated starches were exposed to different microwave conditions (power 640, 720, and 800 W, time 60, 120 and 180 s) and changes in morphology, particle size, digestibility, rheological properties, and molecular structure were measured and analyzed. Microwave treatment caused roughness and deformation of granular surfaces, and an increase in granule size. After treatment, the in vitro digestibility of starch was increased, i.e., the RDS increased, but the RS decreased. Microwave treatment decreased the K values of the in-kernel MWI WHBS. Dynamic rheological results showed that the in-kernel MWI WHBS pastes had lower T_G'max, and higher G'_max, G'_90°C, G'_25°C, G'_0.1Hz and G'_20Hz after treatment. The chain-length distribution did not significantly change after microwave treatment. However, the results for molecular size distributions showed that the peaks of amylopectin (R_h = ~100 nm) shifted left and right, indicating that the molecular volume might become smaller or larger under different processing conditions. The primary effects of microwave treatment may be loosening the molecular structure and cutting main chains of amylopectin.

Starch molecular fine structure is associated with protein composition in chickpea seed

Chickpea (Cicer arietinum L.) seed is a nutritional food high in starch and protein. This study aims to find the relationships between the molecular fine structure of starch and the composition of storage proteins and metabolic enzymes, using different chickpea varieties. It is found that storage proteins and starch biosynthetic enzymes influence each other. The initial formation of amylopectin molecules is affected by storage proteins, as suggested by the positive correlation (p < 0.01) between the average molecular size of amylopectin and total protein content. In addition, a higher amount of seed globulin could be an indication of higher amylose content and more short - medium amylose chains (degree of polymerization, DP, 118-2000). This study might assist selection of chickpea varieties with desirable qualities, such as low starch digestibility.

Rheological behaviors, structural properties and freeze-thaw stability of normal and waxy genotypes of barley starch: a comparative study with mung bean, potato, and corn starches

The rheological behaviors, structural properties and freeze-thaw stability of starch isolated from Tetonia barley (Normal genotype, Reg. No. CV-334, PI 646199) and Transit barley (Waxy genotype, Reg. No. CV-348, PI 660128) were investigated, along with other common starch sources for comparison. Transit barley starch showed the highest loss tangents (tan δ) during a frequency sweep test, which suggested a predominance of elastic properties over viscous properties. However, the tan δ of Tetonia barley starch was similar to that of potato starch, which indicated more solidity in comparison to Transit barley starch. Transit barley starch had the highest gelatinization temperature and the lowest gelatinization enthalpy (P < 0.05). Moreover, Tetonia and Transit barley starches displayed weak diffraction peak intensities by X-ray diffraction analysis. Additionally, Transit barley starch showed the lowest % syneresis even when freeze-thawed up to five cycles (P < 0.05). However, Tetonia barley starch had the worst freeze-thaw stability (P < 0.05), which was verified via scanning electron microscopy analysis of freeze-thawed starch gels. The results of present study indicate that barley starch can be practically applied as a functional ingredient in some specialty starchy foods.

Electrospinning of glutelin-hordein incorporated with Oliveria decumbens essential oil: Characterization of nanofibers

In this study, electrospinning of hordein and glutelin extracted from barley was carried out. Different ratios of the glutelin-hordein blends (25:75, 30:70, 35:65) were tested and the operation parameters including voltage, ejection flow rate and needle-to-collector distance were optimized. According to the scanning electron microscope images, the glutelin-hordein 25:75 blend generated at the voltage of 15 kV, the needle-to-collector distance of 150 mm and the ejection rate of 1 mL/h was selected for the fabrication of uniform nanofibers. The apparent viscosity at the ejection point was decreased with increasing the glutelin concentration from 25 to 35 %. Moreover, the Oliveria decumbens essential oil (ODEO) with different loading concentrations (2-4 % (v/v)) was incorporated into the protein blend. Fourier-transform infrared spectra demonstrated the occurrence of the interactions of proteins the ODEO. The encapsulation efficiency of ODEO in the nanofibers was 79.30 %. The presence of ODEO led to inhibition the growth of Staphylococcus aureus, Escherichia coli and Bacillus cereus in a synthetic medium. The optimal nanofibers showed high antioxidnat activity. The results herein showed the possibility of the production of electrospun nanofibers using barley proteins with promising (bio)functionalities for the active food packaging applications.

Brewing with Starchy Adjuncts: Its Influence on the Sensory and Nutritional Properties of Beer

In brewing, the use of cereals (wheat, barley, maize, rice, sorghum, oats, rye or millet), pseudo-cereals (buckwheat, quinoa or amaranth) and tubers (sweet potato), as starch adjuncts, is being promoted for the production of a variety of high-quality beers, from sensory and nutritional points of view. The sensory properties of the obtained beer depend on the characteristics of each adjunct but also on the forms in which the adjunct is added: whole cereal, grits, malted, extruded grains, torrefied and syrup. Among these common forms, the extruded grains (maize or rice) produce a higher content of aroma compounds in beer. From a nutritional point of view, the use of non-conventional starch adjuncts, such as black rice, buckwheat or sweet potato, leads to an increase in the polyphenol content of the beer, and thus, its antioxidant capacity. Cereals such as maize, rice, sorghum or millet are the most promising for the production of gluten-free beers. A close relationship can be developed between the use of adjuncts in the beer industry and the use of commercial enzymes. Advances made by biotechnology to design new enzymes with different functionalities could be associated to a future increase in adjunct usage in brewing.

Identification of QTL for barley grain size

Background

Barley grain size is one of the key factors determining storage capacity during grain filling. Large, well-filled grains also have a high malt extract potential. Grain size is a complex quantitative trait and can be easily affected by environmental factors thus the identification of genes controlling the trait and the use of molecular markers linked to the genes in breeding program is the most effective way of improving grain size.

Methods

Grain sizes of 188 doubled-haploid (DH) lines derived from the cross of a Japanese malting barley variety (Naso Nijo) and a Chinese feed barley variety (TX9425) were obtained from three different sites in two consecutive years. The average data were used for identifying QTL for grain size.

Results

A total of four significant QTL were identified for grain length (GL) and three for grain width (GW). The two major GL QTL are located at similar positions to the QTL for malt extract on 2H and uzu gene on 3H, respectively. However, the GL QTL on 2H is more likely a different one from the malt extract QTL as most of the candidate genes are located outside the fine mapped QTL region for malt extract. The GL QTL on 3H is closely linked with uzu gene but not due to a pleiotropic effect of uzu. The three QTL for grain width on 1H, 2H and 5H, respectively, were located at same position to those for GL.

Novel parameters characterizing size distribution of A and B starch granules in the gluten network: Effects on dough stability in bread wheat

Our study on six wheat genotypes has revealed strong interaction between gluten and starch to affect dough stability. To establish gluten-starch interaction and its roles in dough stability, we randomly selected 16 wheat genotypes and investigated the physicochemical properties of gluten and starch. The manner in which the starch granules occupied available space in gluten network was quantitatively analyzed using gluten lacunarity and proportion of different sized A-type and B-type starch granules. Positive correlations were found between the morphological attributes (B/A/Lacunarity, B/Lacunarity) and dough stability. The correlation coefficient between B/A/Lacunarity and dough stability was highest, followed by the percentage of unextractable polymeric protein (UPP%), B/Lacunarity and dough stability. Dough mixing properties were strongly affected by gluten-starch interactions, as indicated by novel parameters. Whereas the effect of gluten on its own did not provide any evidence to suggest its concrete role in dough mixing properties because of the various genetic backgrounds.

Effects of physicochemical and structural properties of single and double feedstuffs derived from different botanic sources on in vitro starch digestion and glucose release kinetics

Starch is the largest constituent in animal diets. The aims of this study were as follows: (a) to assess the variability of basic physicochemical properties and in vitro starch digestion of starchy feedstuffs and investigate relationship between physicochemical properties and starch digestion of the feedstuffs, and (b) to explore the effects of different sources of starchy feedstuffs on starch digestion and glucose release. In this study, we determined the inherent molecular structure and granular structure of starch and chemical compositions of seven starchy feedstuffs, as well as starch digestion in single feedstuff and different feedstuffs combined with corn. Scanning electron microscope (SEM) results revealed significant difference between granule shape and size of starch of different feedstuffs. Fourier transforms infrared (FTIR) spectra for barley and wheat had lower (p < 0.05) absorbance band at areas A_860 and A_928 than other feedstuffs, yet rice starch had the lowest value for ratio (R) (1047/1022). Moreover, digestion rate ranged from 0.0157/min for resistant starch (sorghum) to 0.029/min for rapidly starch (broken rice). The principle component analysis (PCA) showed that predicted glycaemic index (pGI) was positively related to A_1022, glucose and rapidly (RDS) content and negatively related to A_995, A_1047, R (1047/1022), resistant starch (RS) and amylose content. Most of the feedstufss with corn combination had no effect on rate of starch digestion. In addition, different starchy feeds and corn combination changed the rate of starch digestion, when barley, however, sorghum combined with corn seemed to affect rate of starch digestion. To sum up, different sources differed in basic physicochemical and structural properties, which would influence the digestion rate of starch and the release of glucose. Combination of different feedstuffs particular sorghum with corn has interactive effect on starch digestion and the release of glucose.

A combined action of amylose and amylopectin fine molecular structures in determining the starch pasting and retrogradation property

Starch fine molecular structures are of essentially important in determining its pasting and retrogradation properties. In this study, 10 different starches from various botanical sources were selected to investigate the combined action of amylose and amylopectin molecules in determining the starch physicochemical properties. Correlation between starch structural parameters with the pasting and retrogradation properties showed that amylose and amylopectin CLDs do not affect these properties in isolation. Such as, the amount of amylose long chains and amylopectin short chains are both positively correlated with the melting temperatures and enthalpy of retrograded starches. Furthermore, relatively longer amylose short to medium chains can result in higher trough and breakdown viscosity, while higher amount of amylopectin medium to long chains result in higher peak viscosity. The results help a better understanding of the importance of amylose and amylopectin fine molecular structures in determining starch functional properties.

Mutation of the d-hordein gene by RNA-guided Cas9 targeted editing reducing the grain size and changing grain compositions in barley

In this study, we successfully knock-out the d-hordein component of barley storage protein using RNA-guided Cas9. Mutation frequencies of 25% and 14% at two different target sites were obtained. Homozygous mutant plants that were T-DNA free were identified in the T1 generation. Barley grains without d-hordein proteins from T2 seeds showed a significantly reduced grain size compared to the parent plant and control non-edited line. The protein matrix surrounding the starch granules was increased, whereas the starch granules themselves were decreased in size in the mutant plants compared to controls. The main effect of a lack of d-hordein was a considerable decrease in the prolamines and an increase in the glutenins. The changes of other grain composition included the increased starch content, amylose content, and β-glucan content. The roles of d-hordein mutation on barley grain size and grain composition remain to be studied.

Novel insights into the effect of drought stress on the development of root and caryopsis in barley

Drought is a common natural disaster in barley production, which restricts the growth and development of barley roots and caryopses seriously, thereby decreasing yield and debasing grain quality. However, mechanisms for how drought stress affects barley caryopses and roots development under drought stress are unclear. In this paper, Suluomai1 was treated with drought from flowering to caryopses mature stage. The morphological and structural changes in roots growth and caryopses development of barley were investigated. Drought stress increased root/shoot ratio and eventually led to the 20.16% reduction of ear weight and 7.75% reduction of 1,000-grain weight by affecting the biomass accumulation of roots and caryopses. The barley roots under drought had more lateral roots while the vessel number and volume of roots decreased. Meanwhile, drought stress accelerated the maturation of caryopses, resulting in a decrease in the accumulation of starch but a significant increase of protein accumulation in barley endosperm. There was a significantly positive correlation (0.76) between the area of root vessel and the relative area of protein in endosperm cells under normal condition and drought increased the correlation coefficient (0.81). Transcriptome analysis indicated that drought induced differential expressions of genes in caryopses were mainly involved in encoding storage proteins and protein synthesis pathways. In general, drought caused changes in the morphology and structure of barley roots, and the roots conveyed stress signals to caryopses, inducing differential expression of genes related to protein biosynthesis, ultimately leading to the increase in the accumulation of endosperm protein. The results not only deepen the study on drought mechanism of barley, but also provide theoretical basis for molecular breeding, high-yield cultivation and quality improvement in barley.

The Brewing Industry and the Opportunities for Real-Time Quality Analysis Using Infrared Spectroscopy

Brewing is an ancient process which started in the middle east over 10,000 years ago. The style of beer varies across the globe but modern brewing is very much the same regardless of the style. While there are thousands of compounds in beer, current methods of analysis rely mostly on the content of only several important processing parameters such as gravity, bitterness, or alcohol. Near infrared and mid infrared spectroscopy offer opportunities to predict dozens to hundreds of compounds simultaneously at different stages of the brewing process. Importantly, this is an opportunity to move deeper into quality through measuring wort and beer composition, rather than just content. This includes measuring individual sugars and amino acids prior to fermentation, rather than total °Plato or free amino acids content. Portable devices and in-line probes, coupled with more complex algorithms can provide real time measurements, allowing brewers more control of the process, resulting in more consistent quality, reduced production costs and greater confidence for the future.

Nutritional quality and in vitro digestion of immature rice-based processed products

The nutritional contents of rice decreased as grains matured, and pepeta-type processing improves the nutritional properties and in vitro protein digestibility of rice.

New insights into amylose and amylopectin biosynthesis in rice endosperm

How various isoforms of rice-starch biosynthesis enzymes interact during amylose and amylopectin synthesis is explored. The chain-length distributions of amylopectin and amylose from 95 varieties with different environmental and genetic backgrounds were obtained using size- exclusion chromatography, and fitted with biosynthesis-derived models based on isoforms of starch synthase (SSI-SSIV), starch branching enzyme (SBE, including SBEI and SBEII) and granule-bound starch synthase (GBSS) that are involved in amylose and amylopectin synthesis. It is usually thought that these are synthesized by separate enzymes. However, the amount of longer amylopectin chains correlated with that of shorter amylose chains, indicating that GBSS, SBE and SS affect both amylose and amylopectin synthesis. Further, the activity of GBSS in amylose correlated with that of SS in amylopectin. This new understanding of which enzymes are suggested by the statistics to be involved in both amylose and amylopectin synthesis could help rice breeders develop cereals with targeted properties.