Barley Starch Research Articles

Barley SS2a single base mutation at the splicing site led to obvious change in starch

Starch biosynthesis is a complex process that relies on the coordinated action of multiple enzymes. Resistant starch is not digested in the small intestine, thus preventing the rapid rise of the glycemic index. Starch synthase 2a (SS2a), a key enzyme in amylopectin biosynthesis, has significant effects on starch structure and properties. In this study, we identified an ss2a null mutant (M3-1413) with a single base mutation from an ethyl methane sulfonate (EMS)-mutagenized population of barley. The mutation was located at the 3´ end of the first intron of the RNA splicing receptor (AG) site, resulting in abnormal RNA splicing and two abnormal transcripts of ss2a, which caused the inactivation of the SS2a gene. The starch structure and properties were significantly altered in the mutant, with M3-1413 containing decreased total starch and increased amylose and resistant starch levels. This study sheds light the effect of barley ss2a null mutations on starch properties and helps to guide new applications of barley starch to develop nutritious food products.

Dry heating affects the multi-structures, physicochemical properties, and in vitro digestibility of blue highland barley starch.

As a physical method for starch modification, dry heating treatment (DHT) at high temperatures (150 and 180°C, respectively) was applied to blue highland barley (BH) starch with different durations (2 and 4 h). The effects on its multi-structures, physicochemical properties, and in vitro digestibility were investigated. The results showed that DHT had changed the morphology of BH starch, and the diffraction pattern remained an "A"-type crystalline structure. However, with an extension of DHT temperature and time, the amylose content, gelatinization temperature, enthalpy value, swelling power, and pasting viscosity of modified starches decreased, while the light transmittance, solubility, and water and oil absorption capacities increased. Additionally, compared with native starch, the content of rapidly digestible starch in modified samples increased after DHT, whereas those of slowly digestible starch and RS decreased. Based on these results, the conclusion could be drawn that DHT is an effective and green way to transform multi-structures, physicochemical properties, and in vitro digestibility of BH starch. This fundamental information might be meaningful to enrich the theoretical basis of physical modification on BH starch and extend the applications of BH in the food industry.

Combined ultrasound and germination treatment on the fine structure of highland barley starch

Highland barley is a grain crop grown in Tibet, China. This study investigated the structure of highland barley starch using ultrasound (40 kHz, 40 min, 165.5 W) and germination treatments (30℃ with 80% relative humidity). The macroscopic morphology and the barley's fine and molecular structure were evaluated. After sequential ultrasound pretreatment and germination, a significant difference in moisture content and surface roughness was noted between highland barley and the other groups. All test groups showed an increased particle size distribution range with increasing germination time. FTIR results also indicated that after sequential ultrasound pretreatment and germination, the absorption intensity of the intramolecular hydroxyl (–OH) group of starch increased, and hydrogen bonding was stronger compared to the untreated germinated sample. In addition, XRD analysis revealed that starch crystallinity increased following sequential ultrasound treatment and germination, but a-type of crystallinity remained after sonication. Further, the Mw of sequential ultrasound pretreatment and germination at any time is higher than that of sequential germination and ultrasound. As a result of sequential ultrasound pretreatment and germination, changes in the content of chain length of barley starch were consistent with germination alone. At the same time, the average degree of polymerisation (DP) fluctuated slightly. Lastly, the starch was modified during the sonication process, either prior to or following sonication. Pretreatment with ultrasound illustrated a more profound effect on barley starch than sequential germination and ultrasound treatment. In conclusion, these results indicate that sequential ultrasound pretreatment and germination improve the fine structure of highland barley starch.

The role of guar gum in improving the gel and structural characteristics of germinated highland barley starch

Germinated highland barley has been shown to have many health benefits, but the weakening of the starch gel properties during the germination limits its further application. In this study, germinated highland barley starch (GBS) was obtained after germination treatment. Guar gum (GG) was added to explore the effects of gelatinization on the rheology, gel and structural characteristics of GBS, and the potential of preparing gel-based products was also evaluated. The results showed that the addition of GG significantly increased the viscosity, gel strength and viscoelasticity of GBS, which was beneficial to the formation of gel, and promoted its formation of an ordered and compact gel network structure. The study provides a theoretical reference for the preparation of gel-based food with highland barley starch, and increases the application range of highland barley.

Barley thermoplastic starch nanocomposite films reinforced with nanocellulose

Abstract Despite being one of the starch producers, barley has yet to be widely studied for thermoplastic starch applications, including nanocellulose thermoplastic composites, due to its uses in the food and beverage industries. However, only 20% of barley is used in the malting industry to produce both alcoholic and non-alcoholic beverages, and 5% is used as an ingredient in a wide variety of foods. As the fourth most important cereal in the world after wheat, corn, and rice, barley can be considered an interesting biomass source to produce biodegradable thermoplastics, stemming from its starch constitution. Therefore, this review attempts to highlight the barley starch properties and its potential utilization for nanocellulose thermoplastic starch composites. Several studies involving barley-based starch in thermoplastic production and nanocellulose reinforcement for properties enhancement are also reviewed, particularly in the attempt to provide various options to reduce and replace the uses of harmful petroleum-based plastic.

Intrinsic and extrinsic factors drive differences in the gelatinisation behaviour of barley and malt starch

We studied the impact of malting on barley starch gelatinisation properties and whether observed differences are due to changes in extrinsic or intrinsic factors. We isolated the total starch and large and small starch granules fractions from barley and malt samples and subjected them to DSC. The peak gelatinisation temperature for malt starch was, on average, 1.2 °C higher than for barley starch. The malting process and endosperm breakdown products were each responsible for half of this difference. The presence of water-extractable, non-starch components (sugars, minerals, protein and starch hydrolysis products,…) increased the intrinsic starch gelatinisation temperatures by 2.2–4.7 °C for barley and 3.6–5.3 °C for malt. The small starch granule fractions from barley had a 3.1 °C higher peak gelatinisation temperature than large granule fractions. No effect of malting was observed here. These findings indicate that matrix effects and starch granule size must be considered when addressing starch conversion during brewing.

The relationship between starch structure and digestibility by time-course digestion of amylopectin-only and amylose-only barley starches

The multi-scale structural dynamics of amylopectin-only barley starch (APBS), normal barley starch (NBS), and amylose-only barley starch (AMBS) digested with amylolytic enzymes for 120 min were investigated in this study. For all starches, 0–20 min was identified as a rapid digestion stage, followed by a 20–120 min slow digestion. For APBS and NBS, the content of short chains (DP ≤ 12) and the thickness of crystalline and amorphous nano-lamellae increased, whereas the crystallinity decreased, and pores were generated on the granular surface during the rapid digestion stage. At the following slow digestion stage, the branching degree and relative amount of double helices increased, the crystalline and lamellar structures were lost, and the hydrolyzed starch segments aggregated. For AMBS, the rapid digestion stage was characterized by an increased content of short chains (DP ≤ 8) and B-type crystals and decreased amounts of V-type crystals. Furthermore, the lamellar and granular structures were lost, and digestion residues aggregated during the first stage of AMBS, which were formed in the second digestion stage of APBS and NBS. The second slow digestion stage of AMBS was characterized by an increased branching degree and a decreased relative content of single helices. It is suggested that the aggregated digestion residues at the initial digestion stage are the main reason for the overall low digestibility of AMBS.

Effect of Lactiplantibacillus plantarum and Saccharomyces cerevisiae fermentation on the multi-scale structure and physicochemical properties of highland barley starch

Modified starch was better suitable for food processing, and fermentation was one of the effective methods to modify starch. This study investigated the separate and synergistic fermentation of Lactiplantibacillus plantarum and Saccharomyces cerevisiae could whether affect the multi-scale structure and physicochemical properties of highland barley starch (HBS). The results of multi-scale structure determination of HBS showed that compared with unfermented HBS (32.27%), fermentation showed a significant increase in relative crystallinity (35.49–39.81%), while the crystal type of HBS as observed from X-ray diffraction (A-type crystalline pattern) did not change. The small angle X-ray scattering revealed that fermentation reduced the amorphous region and increased the crystalline layer thickness of the HBS. Consequently, the changes in the physicochemical properties showed that the peak viscosity, trough viscosity, and final viscosity of HBS were reduced after fermentation, and the aging of starch gel was delayed significantly. Our results showed that Lactiplantibacillus plantarum and Saccharomyces cerevisiae fermentations improve the physicochemical properties of HBS by modifying the multi-scale structure of starch, especially the synergistic fermentation effect was more effective.

Highland Barley Starch: Structures, Properties, and Applications.

Highland barley (HB) is a nutritious crop with excellent health benefits, and shows promise as an economically important crop with diverse applications. Starch is the main component of HB and has great application potential owing to its unique structural and functional properties. This review details the latest status of research on the isolation, chemical composition, structure, properties, and applications of highland barley starch (HBS). Suggestions regarding how to better comprehend and utilize starches are proposed. The amylopectin content of HBS ranged from 74% to 78%, and can reach 100% in some varieties. Milling and air classification of barley, followed by wet extraction, can yield high-purity HBS. The surface of HBS granules is smooth, and most are oval and disc-shaped. Normal, waxy, and high-amylose HBS have an A-type crystalline. Due to its superb freeze-thaw stability, outstanding stability, and high solubility, HBS is widely used in the food and non-food industries. The digestibility of starch in different HB whole grain products varies widely. Therefore, the suitable HB variety can be selected to achieve the desired glycemic index. Further physicochemical modifications can be applied to expand the variability in starch structures and properties. The findings provide a thorough reference for future research on the utilization of HBS.

Removing starch granule-associated surface lipids affects structure of heat-moisture treated hull-less barley starch

The effects of starch granule-associated surface lipids removal on hull-less barley starch structure formed by heat-moisture treatment were investigated. Removing surface lipids made the peak at 2θ of 13° disappear and resulted in higher lamellar peak intensity after harsh treatment and a lower reduction in mass fractal dimension (from 2.49 to 2.43) and radius of gyration (from 24.3 to 24.0) when temperature increased from 100 to 120 °C at 20 % moisture. Treatment at 25 % moisture and 120 °C decreased relative crystallinity (from 15.73 % to 7.43 %) and Gaussian peak area (from 646.7 to 137.7) of native starch, and decreased relative crystallinity (from 14.24 % to 12.56 %) and Gaussian peak area (from 604.1 to 539.6) for starch without surface lipids. Different trends of change in lamellar thickness, linear crystallinity, peak temperatures, and enthalpy of gelatinization were observed among modified starches with increasing temperature and/or moisture content. These results demonstrate that removing surface lipids changes structure of heat-moisture treated starch.

Physicochemical properties and in vitro digestibility of highland barley starch with different extraction methods

The objective of this study was to compare the structural, thermal, rheological and digestive properties of highland barley starch (HBS) by different extraction methods. Five techniques were used to extract HBS: Alkali extraction, Ultrasound extraction, double enzyme extraction (DE), three enzyme extraction (TE) and ultrasonic assisted TE (U-TE). The results indicated that the Ultrasound extracted HBS had fewer Maltese crosses, lower molecular weight (Mw), and higher content of damaged starch (P < 0.05). Meanwhile, DE extracted HBS had higher Mw, and the content of short amylopectin than that of Alkali extracted HBS (P < 0.05). Additionally, the DE extracted HBS showed the highest relative crystallinity and good short-range ordered structure, which led to the outcome of stronger thermal stability and higher values of G′ and G′′ (P < 0.05). These results indicated that enzymatic extraction could better protect the resistance of HBS by protecting its physicochemical properties.

Tribo-electrostatic separation of binary mixtures from polymeric and food materials

Tribo-electrostatic separation in a free-fall separator with a set of prepared mixtures from seven powder materials was investigated, five of them being polymers, whilst the other two are commonly used powders of food origin (cellulose, PTFE, barley starch, whey protein, high-density polyethylene, polyethylene and polyamide). Quantification of material content on the separated fractions attached to the electrodes led to deduce a triboelectric series, where materials are ranked in a sequential mode according to their charging behavior. The obtained material proportion in the separated fractions partially reproduces the idea that, the farther apart two materials are located in the triboelectric series, the larger the difference between their relative proportions on each electrode. The experimental work is supplemented with an estimation of the relative strength of forces acting on the charged particles as they move to the electrodes.

Extraction and characterization of waxy and normal barley β-glucans and their effects on waxy and normal barley starch pasting and degradation properties and mash filtration rate

Interactions between β-glucan and starch influence the health benefits of barley-based foods and barley brewing performance. Here, we characterized β-glucans from waxy and normal barley varieties and compared the effects of different β-glucans on the pasting and degradation of waxy and normal barley starches as well as the filterability of mashes from unmalted waxy and normal barley. Waxy barley Zangqing18 β-glucan displayed more compact micrographic features, higher molecular weight, larger particle size, higher thermal decomposition temperature and lower rheological viscosity than normal barley Zangqing2000 β-glucan. β-Glucan not only significantly decreased the pasting viscosities of waxy and normal starches but also lowered the pasting temperatures and peak times of normal starch, likely by inhibiting granule swelling and disrupting the integrity of the continuous phase. β-Glucan also decreased in vitro digestion extent of starch and increased the resistant starch. The unmalted waxy barley had a mash filtration rate much faster than normal barley because starch and β-glucan in waxy barley were rapidly and completely digested and formed more open filter passages. The effects of β-glucan on starch properties varied with the types and contents of β-glucans, whilst the types of starches showed more significant effects. Chemical compounds studiedβ-Glucan (Pubchem CID: 439262); Amylopectin (Pubchem CID: 439207); Starch (Pubchem CID: 156595876).

Utilising phase diagram to understand barley starch microsphere preparation in an aqueous two-phase system

In this work, a waxy barley starch-PEG aqueous two-phase system (ATPS) phase diagram was constructed, and starch microsphere preparation was explored at different phase diagram positions. The aim was to investigate starch-PEG ATPS phase behaviour and relate this to starch crystallisation and microsphere formation. The hypothesis was that phase diagram position would influence the starch microsphere preparation and the properties of the microspheres. The microsphere formation process was investigated with regard to microsphere development and starch crystallisation kinetics. Microsphere physicochemical properties and their development during different stages of the preparation were studied by examining freshly produced, freeze-dried, and redispersed microspheres. Enzymatic hydrolysis of redispersed microspheres was also investigated. It was possible to produce microspheres from different positions in the phase diagram using 24 h incubation at 25 °C. However, the operational area for the used production conditions was relatively small compared to the biphasic region of the phase diagram. The main findings were that the starch-PEG ATPS phase behaviour can affect the rate of microsphere formation and particle size, but the additional properties of the dried and redispersed microspheres did not differ to a considerable extent. Thus, we have identified a robust production space where production parameters such as time to obtain microspheres can be considerably influenced by the ATPS system phase diagram position.

Impact of a Full Range of Amylose Level on Pasting and Gelling Properties of Barley Starches at High‐Temperature Heating

AbstractPasting and gelling behaviors of barley starches isolated from Cinnamon (waxy of 3.3% apparent amylose; WB), Golden Promise (normal of 26.2% amylose; NB), and amylose‐only (high‐amylose of 97.8% amylose; AO) varieties were examined over 95–140 °C cooking. Gelatinization temperatures of AO starch were significantly higher than those of WB and NB, thereby the former displaying negligible pasting viscosity at 95 °C heating. At 140 °C, AO starch was completely gelatinized and able to develop viscosity, particularly at the final pasting stage. Gel hardness of NB gradually decreased with higher cooking temperatures. After 140 °C cooking and storage, only AO starch formed a gel, exhibiting the largest hardness among the studied gels or pastes. Gelation mechanisms of the barley starches at 95—140 °C cooking were elucidated by visualizing their gel/paste microstructures under scanning electron microscopy. The insightful information on the physicochemical properties of the barley starches possessing 3.3–97.8% amylose will be meaningful for their industrial applications.

Electron beam irradiation application for improving the multiscale structure and enhancing physicochemical and digestive properties of acetylated naked barley

The study used electron beam (EB) irradiation pretreatment to prepare acetylated (AC) naked barley starch. EB pretreatment enhanced the degree of substitution in acetylation from 0.027 to 0.109 %. The starch granules treated with EB and AC had a rough surface but maintained integrity. EB depolymerized the starch structure, providing opportunities for molecular rearrangement, thereby increasing the efficiency in the subsequent acetylation process. Therefore, EB pretreatment decreased AC starch amylose content (27.82 to 21.61 %), amylopectin molecular weight, relative crystallinity (31.04 to 26.23 %), short-range order, and increased amylose molecular weight comparing EB or AC-treated alone. These structural changes improve the properties of starch; thus, EB pretreatment reduced the thermal transition temperature, gelatinization enthalpy, pasting parameters, rapidly-digestible starch content (67.09–51.74 %), solubility, and improved content of slowly-digestible starch (23.82–36.65 %) and resistant starch (9.09–11.62 %). EB pretreatment can enhance efficiency and improve the structure and performance of acetylated modified starch.

Effects of Different Extraction Methods on the Gelatinization and Retrogradation Properties of Highland Barley Starch.

The purpose of this study was to compare the gelatinization and retrogradation properties of highland barley starch (HBS) using different extraction methods. We obtained HBS by three methods, including alkali extraction (A-HBS), ultrasound extraction (U-HBS) and enzyme extraction (E-HBS). An investigation was carried out using a rapid viscosity analyzer (RVA), texture profile analysis (TPA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and Fourier-transform infrared spectrometry (FTIR). It is shown that the different extraction methods did not change the crystalline type of HBS. E-HBS had the lowest damaged starch content and highest relative crystallinity value (p < 0.05). Meanwhile, A-HBS had the highest peak viscosity, indicating the best water absorption (p < 0.05). Moreover, E-HBS had not only higher G′ and G″ values, but also the highest gel hardness value, reflecting its strong gel structure (p < 0.05). These results confirmed that E-HBS provided better pasting stability and rheological properties, while U-HBS provides benefits of reducing starch retrogradation.

Morphological and thermo-mechanical characterization of sweet potato starch based nanocomposites reinforced with barley starch nanoparticles.

The aim of present study was to develop and characterize the biodegradable sweet potato starch-based nanocomposite films reinforced with barley starch nanoparticles (SNP). Sweet potato starch-based films with varying concentrations of barley SNP (5-25% w/w) were manufactured by adopting solution casting method using glycerol as a plasticizer. The morphology, thickness, transparency, water solubility, water vapor transmission rate (WVTR), tensile strength, elongation at break and thermal stability properties of nanocomposite films were evaluated. The results showed that the incorporation of barley SNP led to a significant increase in tensile strength from 2.63 (control film) to 8.98MPa (nanocomposite with 15% (w/w) SNP). Compared with the native starch film, the surface of the nanocomposite films became more rough and uneven with the increasing concentration of nanofillers. High concentration of SNP (upto 25%, w/w) significantly decreased the transparency and WVTR, and water solubility (upto 20%, w/w) of nanocomposite films. The WVTR decreased from 3294.53 to 349.06g/m2/24h. In addition, the thermal stability of nanocomposites got improved after incorporation of SNP into starch-film matrix.

Preparation and characterization of canola oil-in-water Pickering emulsions stabilized by barley starch nanocrystals

Pickering emulsions (PE) have gained attention in food engineering applications. This study aimed to elaborate stable PE of canola oil by using barley starch nanocrystals (BSNC) as stabilizers which were prepared by acid hydrolysis of the starch and used in five nanocrystals to oil weight ratios (0.026, 0.038, 0.051, 0.076 and 0.102) to stabilize the emulsions. The size of the nanocrystals ranged between 43 and 396 nm and their average size was 141 nm. Emulsion droplet size decreased as the content of BSNC increased. It was observed by backscattering that the sedimentation of the droplets occurred slower in the systems having a higher amount of BSNC. All emulsions were stable to coalescence and creaming during storage and it was observed that, the most stable emulsions were those having nanocrystals to oil ratio of 0.24. Apparent viscosities of the emulsions increased with the content of nanocrystals. It was concluded that barley starch nanocrystals are suitable to produce and stabilize food-grade Pickering emulsions. • Barley starch nanocrystals were obtained by acid hydrolysis of starch. • Barley starch nanocrystals positively stabilized Pickering emulsions of canola oil. • A relatively small number of nanocrystals adequately protected Pickering emulsions against coalescence and phase separation. • Emulsions showed shear thinning behaviors and G′ values were larger that G¨ ones.

Effects of Barley Starch Level in Diet on Fermentation and Microflora in Rumen of Hu Sheep.

Simple SummaryIncreasing the starch level in the diet of ruminants can promote rumen fermentation to a certain extent and improve production performance. However, the degradation of rapidly fermentable carbohydrates in the rumen can lead to the accumulation of large amounts of organic acids (mainly volatile fatty acids and lactic acid), increasing the risk of subacute ruminal acidosis (SARA) in high-yielding ruminants. By changing the fermentation sites of rapidly fermentable carbohydrates, the rumen environment and feed efficiency could be effectively improved. The object of this study was to explore the effects of replacing corn starch with barley starch in the diet of Hu sheep on the fermentation and microflora in the rumen. Our results showed that, starch in the diet cannot be derived entirely from barley, and it is feasible to replace 33% of the corn with barley in the diet for Hu sheep.This study aimed to explore the effects of different levels of barley starch instead of corn starch on the rumen fermentation and microflora when feeding a corn-based diet to Hu sheep. Thirty-two male Hu sheep equipped with permanent rumen fistulas were selected and fed in individual metabolic cages. All sheep were randomly divided into four groups (eight sheep in each group) and fed with four diets containing a similar starch content, but from different starch sources, including 100% of starch derived from corn (CS), 33% of starch derived from barley + 67% of starch derived from corn (33 BS), 67% of starch derived from barley + 33% of starch derived from corn (67 BS) and 100% of starch derived from barley (100 BS). The experimental period included a 14 d adaptation period and a 2 d continuous data collection period. The results showed that the molar proportions of acetate, isobutyrate, butyrate and isovalerate and the ratio of acetate to propionate in the 67 BS and 100 BS groups decreased compared with the CS and 33 BS groups (p < 0.001), while the molar proportions of propionate and valerate increased (p < 0.001). The combination of 33% barley starch and 67% corn starch in the diet improved the production of TVFAs (p = 0.007). The OTUs and Shannon indexes of the CS and 33 BS groups were higher than the 67 BS and 100 BS groups (p < 0.001), and the Chao1 and Ace indexes were higher than the 100 BS group (p < 0.05). In addition, the 33 BS group had increased the relative abundances of Bacteroidetes, Prevotella and Ruminococcus and the abundances of Fibrobacter succinogenes, Ruminococcus flavefaciens, Streptococcus bovis, Selenomonas ruminantium and Prevotella brevis relative to the CS group (p < 0.05). These results indicate that the substitution of 33% of the CS with BS did not change the rumen fermentation pattern relative to the CS group, and increased the richness and diversity of the rumen microbes in Hu sheep compared with other two starch substitute groups.