Co-migration of phytate with cereal β-glucan and its role in starch hydrolysis in-vitro

This study investigated the mechanisms of the co-migration of phytic acid during β-glucan isolation and its contribution to the retardation of starch hydrolysis in vitro. During the isolation, phytic acid precipitated together with β-glucan when ethanol was added as the precipitation solvent. The precipitation of phytic acid was reduced by lowering the pH or the ethanol concentration. When 20% (NH₄)₂SO₄ was used as the precipitation solvent, only minor phytic acid was found in isolated β-glucan, because phytic acid did not precipitate by this solvent. In the in vitro starch hydrolysis test, the isolated oat β-glucan (OBG) containing 3.9% co-migrated phytic acid showed better retardation effect than OBG containing 0.6% phytic acid. Therefore, we concluded that the co-migration of phytic acid was dependent on the chosen isolation procedure and conditions, and both intrinsic phytic acid and viscosity contributed to the retardation of starch hydrolysis.     

Effect of home processing on ascorbic acid and β-carotene content of spinach (Spinacia oleracia) and amaranth (Amaranthus tricolor) leaves

The present investigation was conducted to study the concentration of ascorbic acid and -carotene in spinach and amaranth leaves as affected by various domestic processing and cooking methods which included storage of leaves in polythene bags or without packing for 24 and 48 hours in refrigerator at 5 °C; at 30 °C in polythene bags; drying (sun and oven); blanching (5, 10, 15 min); open pan and pressure cooking. Ascorbic acid content of fresh leaves was 624.1 to 629.0 mg and -carotene content was 35.3 to 53.1 mg/100 g dry weight. The percent loss of ascorbic acid ranged from 1.1 to 6.3 and 55.3 to 65.9 while lower losses (0.0 to 1.3 and 1.5 to 2.1) of -carotene were observed in leaves stored in refrigerator and at 30 °C, respectively. A markedly greater reduction in ascorbic acid and -carotene was observed in dried, blanched and cooked leaves. The study recommended the storage of leaves in refrigerator, drying in oven, blanching for shorter time and cooking in pressure cooker for better retention of these two vitamins.     

Predicting wheat quality – consequences of the ascorbic acid improver effect

Genotype and environment sets of wheat cultivars and breeding lines were tested for bread making, dough mixing, dough rheology, protein composition and thiol/disulphide composition to find methods that could identify wheat with high baking quality (high-BQ) and moderate work input (moderate-WI) requirement using the mechanical dough development system. Wheat with these properties generally had a high baking response to ascorbic acid (AA) and a GluD1a (HMW-GS 2 + 12) allelic composition. Strong wheat with high WI and high-BQ generally had low baking response to AA and a GluD1d (HMW-GS 5 + 10) allelic composition. Using protein composition data to identify wheat of high-BQ (with AA) and moderate-WI, it was best to select wheat with as high as possible percent of SDS-unextractable polymeric protein (%UPP) in flour and as low as possible %UPP in total polymeric protein. Using a dough extension test for identifying wheat of high-BQ (with AA) and moderate-WI, it was best to select wheat with intermediate values for maximum resistance to extension (Rmax) and for values of extension at Rmax as high as possible within the intermediate Rmax range. Cysteine content of protein fractions and glutathione content of flour gave mostly poor to weak correlations with all baking and mixing properties.     

Effect of Indoleacetic acid （IAA） on the Negative Phototropism of Rice Root

To explore the effects of IAA on negative phototropism of rice (Oryza sativa L) root, agar block containing IAA was unilaterally applied on root tip to examine the phototropic response of root to exogenous IAA, and microstructure of the bending part was observed with an optical microscope. The growth of seminal roots could be regulated by exogenous IAA as well as light,as a result the root bent towards the site treated, causing asymmetric growth of the root cells at the elongation zone and consequently bending growth. IAA concentration in the shaded side of adventitious root increased much greater at 1.5 h after the start of irradiation. The unequal lateral IAA distribution can be concluded to be the main cause for negative phototropism of rice root.     

Changes in β-carotene and ascorbic acid content of fresh amaranth and fenugreek leaves during storage by low cost technique

Leafy vegetables are highly perishable and their shelf life depends on duration and conditions of storage. A low cost storage structure was used to extend the shelf life of amaranth and fenugreek and their quality was evaluated on the basis of retention of -carotene, ascorbic acid and chlorophyll during storage. Losses of -carotene ranged from 46.5 to 85.0% for amaranth and 24.0 to 73.0% for fenugreek depending on duration and conditions of storage. Similarly ascorbic acid retention varied from 9–32% for amaranth and 23–80% for fenugreek. Results showed that the degradation of quality parameters was faster at ambient conditions and packaging of leaves in low density polyethylene bags was beneficial in improving shelf life and nutritive value. Low cost storage structure was similar to low temperature storage for retention of -carotene, ascorbic acid, chlorophyll content and enhancement of shelf life.     

Understanding the role of oat β-glucan in oat-based dough systems

B-glucan is one of the components that differentiate oats from other cereals and that contribute to the health-related value of oats. However, so far oats cannot easily be applied in bread-like products without loss of product quality. Here we have studied how the content and viscosity of oat β-glucan affect the technological properties of oat dough in both a gluten-free and a gluten-containing system. In both systems, increasing the β-glucan concentration resulted in an increase of dough stiffness and in a reduction of dough extensibility. β-glucan negatively impacted the elastic properties that additional wheat gluten conferred to oat dough. This effect was smaller for medium-viscosity β-glucan than for high-viscosity β-glucan. Interestingly, dough made from low β-glucan flour (<2%) had increased gas retention capacity. Overall, the impact of β-glucan on the properties of oat dough systems was governed by concentration and viscosity, with or without additional wheat gluten. Our findings indicate that β-glucan is a key component that determines the rheology of oat-based dough systems and, with that, the technological functionality of oat in dough systems.     

Pre-harvest glyphosate application effects on properties of β-glucan from oat groats

Pre-harvest glyphosate is applied to cereal grains to control weed growth. However, it has been claimed that oat (Avena sativa L.) composition is affected by pre-harvest glyphosate application. The research was conducted to evaluate differences in properties of β-glucan in grains of pre-harvest glyphosate treated versus untreated oat plants. Two oat cultivars (Rockford and Souris) were grown at Minot and Prosper, ND, in 2015, and glyphosate was sprayed during the soft dough stage, hard dough stage, or not applied. β-glucan viscosity was not significantly (p > 0.05) affected by treatment at soft dough (1082 cP) or mature (1166 cP) stages compared with untreated (1150 cP) controls. Applying glyphosate at the soft dough stage significantly (p < 0.05) reduced the content and solubility of the β-glucan versus untreated samples. β-glucan content and solubility in oat treated at soft dough were 4.35% and 52.1%, respectively, while in untreated samples were 4.65% and 60.6%, respectively. Treatment at soft dough and hard dough stages significantly (p < 0.05) increased weight average molecular weight (M_w) of the high molecular weight fraction of soluble β-glucan (4.4 × 10⁶ and 3.8 × 10⁶, respectively), compared with untreated controls (3.5 × 10⁶). The M_w of the low molecular weight fraction of soluble β-glucan fraction significantly (p < 0.05) increased at soft and hard dough treatments (5.5 × 10⁵ and 3.3 × 10⁵, respectively), versus untreated samples (3.0 × 10⁵). Therefore, glyphosate can be applied when the grain has reached physiological maturity or thereafter.     

Effect of genotype, environment and agronomic management on β-glucan concentration of naked barley grain intended for health food use

(1,3:1,4)-β-d-Glucan is an important bioactive that contributes to the ability of barley foods to help prevent type-2 diabetes. Realisation of these benefits requires understanding of genotype and environment effects on β-glucan concentration and how this variation affects biological activity of barley foods. Field experiments showed genetic variation in β-glucan concentration (3.0-7.0 g/100 g DM), but also considerable variation between environments. β-Glucan concentrations were lower in the wet summer of 2007 than 2006 or 2009; and slightly less in the dry summer of 2006 than 2009. β-Glucan was not diluted by higher grain yields. The role of β-glucan as an assimilate buffer adds complexity to interpreting the effects of environment during grain filling. Autumn sowing and fungicide increased the duration of grain filling, decreased β-glucan concentration but increased environmental stability; possibly due to lower demand for assimilate buffering. Lodging and foliar disease decreased β-glucan concentration, by decreasing assimilate supply leading to remobilisation of carbohydrate from β-glucan, so that fungicide increased β-glucan in some disease-susceptible accessions. Sequential harvesting starting at GS 91 suggested an optimum harvest window for maximum β-glucan concentration. The variability in β-glucan reported here between genotypes and environments was sufficient to affect control of post-prandial blood glucose in healthy volunteers.     

Optimization of the β-glucan extraction conditions from different waxy barley cultivars

The purpose of this work is to provide a complete study of the influence of several operational parameters on the aqueous extraction of β-glucan from barley, and to find an optimal combination of factors that maximize the extraction yield. Temperature, pH, extraction time, particle size, stirring rate and solvent:flour ratio were identified as the critical factors affecting the extraction process. Preliminary experiments were useful to set the extraction temperature at 55 °C (maximum extractability of β-glucan below gelatinization temperature of starch), and pH close to neutrality. In order to determine the optimal combination of the other four factors, a Taguchi experimental design approach was used: four variables (three levels) in L₉ orthogonal array. Nine different trials were conducted in duplicate for two different waxy barley cultivars: D24 (hulled; 6.02% β-glucan) and H13 (hulless; 4.64% β-glucan). The optimal conditions obtained from the signal to noise ratio analysis were: particle size, 100 μm; solvent:flour ratio equal to 5; stirring rate, 1000 rpm and extraction time, 3 h. The confirmatory experiment conducted with the optimal conditions provided an extraction yield of 73.4 ± 1.2% for D24 and 62.3 ± 1.8% for H13, corresponding to the maximum and showing that these conditions are valid regardless the composition of the used barley.     

Impact of native form oat β-glucan on starch digestion and postprandial glycemia

Whole grain oats, as a rich source of β-glucan, have been shown beneficial to glycemic control. In the current study, the impact of native form β-glucan in oat grains (NFO-glucan) on starch digestion and postprandial glycemia was investigated. The dry-milling prepared NFO-glucan sample was enriched with native form β-glucan (15.6%), and an in vitro starch digestion assay of NFO-glucan (0.5% starch equivalent) showed a significant decrease of starch digestion rate compared to oat starch (0.5%, w/v). However, pretreatment by either β-glucanase or pepsin significantly increased the starch digestion. Consistently, an in vivo examination on the postprandial glycemia of the cooked NFO-glucan sample using a mouse model displayed a significant decrease of postprandial glycemia compared to gelatinized oat starch. Further experiment on the pasting property of NFO-glucan sample by a rapid visco-analyser demonstrated both β-glucan and protein affected its viscosity profiles. Scanning Electronic Microscope (SEM) observation revealed a network-like native structure of β-glucan that might encapsulate protein and starch to reduce the enzyme accessibility and so the digestion of starch. Novel food processing technologies to maintain the native form of β-glucan in oat grains might be a better way to modulate the postprandial glycemia of oat-based whole grain foods.     

Effects of environment and variety on content and molecular weight of β-glucan in oats

Oat β-glucan has been shown to have cholesterol, insulin and glucose lowering effects, which are related to increased viscosity of the intestinal contents. Some important factors influencing the viscosity are molecular weight, structure and concentration. To study the effect of variety and environment on β-glucan content and molecular weight of β-glucan, four oat varieties were grown in 11 different environments (location × year combinations) in a field experiment. The β-glucan content varied between 2.3 and 3.2% and the average molecular weight of β-glucan between 1.73 and 2.02 × 10⁶ g mol⁻¹. There was a significant difference between varieties and environments for both β-glucan content and molecular weight of β-glucan. The effect of environment was much greater on molecular weight (71%) than on β-glucan content (42%), while the effect of variety was greater on β-glucan content (23%) than on molecular weight (4%). There was also a positive significant correlation between β-glucan content and molecular weight of β-glucan (p < 0.001, r = 0.46). These results show that β-glucan content is a better target for plant breeding than molecular weight. However, both factors are important for the physiological effects of β-glucan, and selection for high β-glucan content will probably also give higher molecular weight.     

Effects of roasting on barley β-glucan,thermal, textural and pasting properties

Different hulled barley cultivars were subjected to roasting in hot sand (280 °C) and the effects on β-glucan extractability, physico-chemical, thermal and pasting properties were studied. The grain puffed upon roasting and grain hardness and colour difference ΔE were significantly lowered. The roasted barley flour had significantly higher water absorption and water solubility index. The cultivars DWR-28, RD-2503 and PL-172 had the highest total β-glucan content (up to 5.47%). Roasting brought about a decrease in the soluble β-glucan content in all the cultivars and this decrease ranged from 4.9 to 25.3%. The β-glucan extractability was not affected by the roasting process but roasting lowered the ratio of soluble to insoluble β-glucan content by 8.1–41.9%. Roasting significantly affected the pasting and thermal properties of the flours, together with an increase in the cooked starch content that ranged from 28.8 to 43.1%.     

Barley grain β-glucan content as affected by nitrogen and irrigation

Barley (Hordeum vulgare L.) with high grain β-glucan content in the soluble dietary fiber fraction may be useful as a specialty crop for human food. In contrast, low β-glucan content is desirable for brewing or animal feed. The objective of this study was to evaluate the effect of nitrogen and irrigation on barley grain β-glucan content. Relationships between barley grain β-glucan content and some agronomic traits were examined. Generally, high nitrogen levels increased barley grain β-glucan content in both years. The N₂ treatment gave the best grain β-glucan contents. A negative effect of irrigation was observed for barley grain β-glucan content. Increased levels of irrigation tended to decrease grain β-glucan content in barley. Non-irrigated treatments commonly had the greatest values for grain β-glucan content in all treatments. Higher positive correlations between β-glucan and protein content were observed in both years. A negative correlation between β-glucan content and 1000 grain weight was significant in 1999 while a negative correlation between β-glucan content and sieve analysis was significant in 2000. It may be concluded that increased nitrogen is desirable for high grain β-glucan content in barley but not irrigation.     

Effect of LaCl_3 on the chilling tolerance of rice seedlings

The rice variety Tesanai 2 is susceptible tochilling. Exposure of the seedlings grown at 28±1℃ and under a photo flux density(PFD) of30μmol/m~2s to 1℃ and under a PFD of 150μmol/m~2s for 2 d caused a physiological disor-der called chilling injury which reduced the sur-vival rate to 50%. The experimental results in-dicated that the activity of scavenge oxygen     

Development of β-glucan enriched wheat bread using soluble oat fiber

Soluble oat fiber (SOF) containing 70% oat β-glucan was incorporated into wheat bread by replacing 10, 12, and 14% of flour in wheat bread formulas. At each level of SOF, bread was made at the farinograph water content defined by the amount of water required to develop a dough consistency of 500 Brabender Units in farinograph tests, and 10 and 20% extra water above the farinograph water content. At the farinograph water content, bread formulated at each level of SOF exhibited lower specific volume and porosity, darker color, higher hardness, and lower springiness and cohesiveness than the control white bread. These negative effects were effectively counteracted by optimizing the water content in bread formulas. For the three levels of bran addition, when the water content was increased by 20% above the farinograph water content, the obtained loaves exhibited similar loaf volume, microstructure, textural properties, and crumb porosity to the control white bread. A serving (28 g) of the developed bread contained respectively 0.95, 1.12, and 1.28 g of β-glucan, which substantially exceed the minimum standard for approved health claims.     

Effect of germination-hydrothermal treatments followed by fractionation on inhibitory factors, β-carotene and iron-zinc bioaccessibility in pearl millet fractions

Combination of strategies involving germination-hydrothermal treatments and fractionation were adopted to separates the native and treated grain into coarse (bran & germ) and fine (endosperm) fractions. The inhibitory factors, polyphenol oxidase, and phytase activity were higher in coarse fractions. On treatment, the phytic acid content in the coarse fraction decreases significantly by 49% while polyphenols decreased 13% in the fine fraction and increased 6% in the coarse fraction. Galloyls reduced by 21% and 48% in the fine and coarse fraction while catechols increased by 74% in the fine fraction and reduced by 27% in the coarse fraction. In the fine fraction, the soluble and insoluble fibre increased by 27.8% and 28.7% while in the coarse fraction is reduced by 23.5% and 24.1%. The β-carotene content reduced slightly in the coarse fraction with no variation in the fine fraction. Iron bioaccessibility was enhanced from 1.79 to 5.7% in the fine fraction and 3.06–6.05% in the coarse fraction. Zinc bioaccessibility increased from 15.44 to 24.67% and 18.59–47.6% in the fine and coarse fraction, respectively. In the treated coarse fraction the iron-zinc bioaccessibility increased due to a significant reduction in phytic acid (49%), insoluble dietary fibre (24%), galloyls (48%) and catechols (27%).     

Effect on the application of large granule urea to irrigated rice

The effects of large granule urea(LOU) to irrigated rice were studied at the farm of China National Rice Research Institute. Experiment soil contained organic C 19.0g/kg, total N 2.2g/kg, total P 0.60g/kg, total K 20.1g/kg and pH6.9.