Barley Starch Research Articles

Effect of pretreatment on the film forming properties of potato and barley starch dispersions

The effects of preheating temperature, glycerol concentration and acid modification on the film-forming properties of potato and barley starches were studied in extension of the starch films and by light microscopy. In addition, the effects of heating pretreatment and acid modification were studied by size exclusion chromatography (SEC). With both starches, the starch: glycerol ratio ranged 100:5 to 100:67 of 3 wt % starch dispersions. Increasing the glycerol content increased the elongation and decreased the tensile strength of potato and barley starch films prepared after preheating at 121 °C. In the case of potato starch at 100:33 starch: glycerol ratio, raising the preheating temperature from 100 to 180 °C caused the tensile strength to increase from 2.4 to 5.0 MPa and the elongation to decrease from 104 to 5%. The mechanical properties of potato starch films underwent a notable change when the preheating temperature was 100 or 121 °C. The molecular mass of amylose decreased from 1100,000 to 670,000. A major change in the molecular mass of potato amylopectin could be detected only after heat treatment at 180 °C. At 121 °C and at 180 °C, starch dispersions exhibited a clear separation into amylose- and amylopectin-rich phases. No continuous films were obtained from acid-modified potato starches with molecular mass of amylose 20,000. With barley starch, as the preheating temperature increased from 100 to 180 °C the tensile strength increased from 2.6 to 4.9 MPa and the elongation decreased from 52 to 5%. At the same time the molecular mass of amylose decreased from 300,000 to 80,000. At 121 °C the granular structure remained, but at 180 °C no granules were left and instead the film consisted of amylopectin droplets and small amylose-rich domains.The strongest films (9.4 MPa), with 7% elongation, were obtained with acid-modified barley starch in which the molecular mass of amylose was 45,000. The tensile strength of both potato and barley starch films increased during storage reaching 9 MPa after 15 days. Elongation of both films decreased markedly during storage.

Heat-induced structural changes of acid-hydrolysed and hypochlorite-oxidized barley starches

The effects of hydrolysis and oxidation on the heat-induced structural changes of barley starch dispersions were studied by dynamic viscoelastic methods and light microscopy. The effects of the modifications on the molecular weight of amylose and amylopectin were investigated by high-performance liquid chromatography (HPLC) with post-column iodine staining. Comparison of the molecular weights of oxidized and acid-hydrolysed barley starch dispersions with the same limiting viscosity values showed that the molecular weight of amylose was decreased more by oxidation than by hydrolysis, whereas the molecular weight of amylopectin was reduced to the same degree. Relative to acid hydrolysis, oxidation also reduced the temperature at which gel-formation occurred and weakened the gels. Irrespective of the type of modification, large amounts of granule residues were left after heating at 120 °C for 20 min. Microstructural studies of the gels showed that both hydrolysed and oxidized starches underwent phase separation into amylose- and amylopectin-rich phases.

Effects on Grain and Malting Quality of Genes Altering Barley Starch Composition

Abstract In this study inbred barley lines carrying waxy and/or high amylose genes were obtained from a cross between Waxy Hector and a breeders» line BE285 (high amylose Glacier×Midas) and assessed for malting quality. Inbred lines were assayed and classified as having none, one or both genes. After malting, waxy lines had a slightly lower hot water extract than normal starch lines. Large effects were demonstrated for both grain nitrogen content and hot water extract in high amylose lines and, particularly, in lines with both genes. Endosperm modification during malting was reduced by both starch mutations. Electron microscopy showed that the phenotype with both genes was characterised by a highly compacted endosperm. During malting, this structure was extremely resistant to modification.

Variation in starch, protein, and fibre of Canadian barley cultivars

Barley (Hordeum vulgare L.) is a major feed in the Maritime region of Canada, but information on the chemical composition of barley cultivars grown in the Maritimes is lacking. Therefore, a study was undertaken to determine if starch, protein, neutral-detergent fibre (NDF), and acid-detergent fibre (ADF) of barley vary from region to region in Canada and to determine if barley cultivars that originated from Eastern Canada exhibit different chemical composition than those that originated from Western Canada. The chemical composition of two-row and six-row, covered and hulless, and feed and malting cultivars were also compared. Seventy-five cultivars were tested in eight environments (i.e. Charlottetown, Ottawa, Brandon, and Bentley in 1991 and 1992). These cultivars were classified into eight classes in four comparisons: eastern vs. western, two-row vs. six-row, hulless vs. covered, and feed vs. malting. Charlottetown grains were relatively low in protein, high in starch, and intermediate in NDF and ADF in comparison with grains produced at the other three locations. This suggests that more research in cultivar development and crop management is needed to increase the protein concentration of barley in the Maritimes. On average, two-row cultivars contained more starch and less fibre than six-row cultivars. Eastern two-row cultivars contained more protein than western two-row cultivars. As expected, hulless barleys contained more starch and protein, but less fibre than covered barleys. Canadian barley cultivars exhibited considerable variation in chemical composition. The cultivar x environment interaction was much smaller than the cultivar effect. Therefore, it is important to identify barley cultivars with high nutritional quality for use in commercial production. Key words: Barley, Hordeum vulgare L., cultivars, starch, protein, fibre

Ruminal Fermentation and Passage of Nutrients to the Duodenum of Lactating Cows Fed Mixture of Corn and Barley

Five Holstein cows were used in a 5 × 5 Latin square design and fed diets containing five different ratios of starch from ground shelled corn and steam-rolled barley. The DMI decreased and both the proportions of OM and starch digested in the rumen increased as barley starch increased in the diet. Corn and barley starches fed in a ratio of 75:25 maximized the proportions of ADF and NDF digested in the rumen. Replacement of 25% of the corn starch with barley starch resulted in the largest increase in the molar percentage of propionate and the largest decrease in the molar percentage of acetate in ruminal fluid. Passage of NAN to the duodenum was not affected by treatment; however, the percentage of nonammonia nonmicrobial N in NAN decreased as barley starch increased. Passage of AA to the duodenum was largest when corn and barley starches were fed in ratios of 100:0 and 0:100 because of the influence of DMI and microbial protein synthesis. Production of milk, CP, and SNF was similar when cows were fed diets containing corn and barley starches in ratios of 100:0, 75:25, and 50:50 but was decreased when the ratios were 25:75 and 0:100. Increased production responses of cows when diets contained larger amounts of starch from ground shelled corn were probably due to increased DMI.

Variation in the chemical composition and test weight of barley and wheat grain grown at selected locations throughout Manitoba

Cultivars of wheat (n = 8) and barley (n = 6) were grown at 12 locations throughout Manitoba over 3 consecutive years. Test weight (TWT = weight of whole grain per volume), and the concentrations of protein, starch, fat, NDF and ADF in the grain from wheat and barley differed (P < 0.05) among cultivars of each grain. Correlation coefficients between measurements were calculated for barley: TWT vs. starch, r = 0.43; TWT vs. NDF, r = −0.66; TWT vs. ADF, r = −0.51; starch vs. NDF, r = −0.49; and they were also calculated for wheat: TWT vs. protein plus starch, r = 0.26; TWT vs. NDF, r = −0.44; TWT vs. ADF, r = −0.31; protein vs. starch, r = −0.50. Variation for TWT and the concentrations of protein, starch, fat, NDF and ADF in the grain from barley and wheat were due both to differences among cultivars and the effect of environment (location and year of growth) on those differences among cultivars. Effects of environment differed among measurements. Variance due to the interaction between cultivar, and location and year of growth (cultivar × environmental variance) was 7.5 and 14.0% of total variance (total variance = environmental variance plus cultivar × environmental variance) for protein in barley and wheat, respectively. Cultivar × environmental variance was also low and ranged from 24.0 to 35.4% of total variance for starch, NDF and ADF in barley and for ADF in wheat. The lower the percentage of cultivar × environmental variance the more predictable were the differences for a measurement among cultivars of a grain across environments. Key words: Grain, wheat, barley, composition, test weight, Manitoba

Hypochlorite Oxidation of Barley and Potato Starch

AbstractThe oxidation of barley and potato starches was studied using sodium hypochlorite as oxidant. The degree of oxidation, depolymerization during oxidation and gel formation of barley starch was compared with the properties of potato starch. The effect of oxidation on gelatinization of starches as well as on amylose‐lipid complex of barley starch was also analyzed. Barley starch was not as easily oxidized as potato starch. In both starches depolymerization of amylopectin and amylose occurred during oxidation. Based on the dissociation enthalpy of amylose‐lipid complex, the lipid‐bound amylose in barley starch was readily oxidized. Oxidation decreased the gelling ability of barley starch. At high level of oxidation gel formation by potato starch was much slower and weaker than by barley starch.

The Standardisation of Infratec 1221 near Infrared Transmission Instruments in the Danish Network Used for the Determination of Protein and Moisture in Grains

The Danish NIR transmission network is used for the determination of protein, moisture and starch in barley and wheat; moisture in rye; oil in rapeseed; and Zeleny in wheat. The network is described briefly. To achieve optimal performance of the field instruments, a standardisation using grain and rapeseed samples has to be conducted at least once a year. The systematic instrument-to-instrument variation is thus virtually eliminated just after standardisation. The random variation between the field instruments and the sub-master is small and not influenced by the standardisation.

Physicochemical Characteristics and Functional Properties of Starch from a High β‐Glucan Waxy Barley

AbstractThe physicochemical properties and functional characteristics of starch from a high β‐glucan waxy barley were compared with those of starches isolated from normal and high amylose barleys. Amylose content of the starches ranged from 1.9 to 34.8%. There was no relationship between amylose content and water binding capacity and gelatinization temperature of the starches. Amylose content and swelling power as well as enzyme susceptibility were negatively correlated. Waxy barley starches had a lower solubility than amylose‐containing starches. High amylose barley starch registered no swelling in the Amylograph. Amylose content in starch proved to be very important for good bread‐ and cake baking quality. Waxy starches did not produce acceptable breads and cakes.The starch from the high β‐glucan barley variety “Shonkin” will be suitable as a thickening agent, but not as an ingredient in bakery products.

Nutritive value of wet distillers' solubles for pigs

Digestibility and nitrogen (N) metabolism were studied to evaluate the nutritive value of wet barley distillers’ solubles (DSB) from an integrated starch-ethanol process for pigs. Eight castrated male pigs (live weight 72-103 kg) were used in a 8 x 3 cyclic change-over design, where the diets were arranged factorially 2x2. The corresponding factors were the protein source (DSB or soya bean meal (SBM)) and the protein level (131 or 162 g crude protein (CP)/kg dry matter (DM)). Faeces and urine were collected in total. The four diets comprised barley, barley starch, minerals and vitamins with either DSB or SBM as the main source of protein. The digestibility of CP(p

Measurement of the biodegradation of starch-based materials by enzymatic methods and composting

The aim of this study was to evaluate the suitability of in vitro enzymatic methods for assaying the biodegradability of new starch-based biopolymers. The materials studied included commercial starch-based materials and thermoplastic starch films prepared by extrusion from glycerol and native potato starch, native barley starch, or crosslinked amylomaize starch. Enzymatic hydrolysis was performed using excessBacillus licheniformis α-amylase andAspergillus niger glucoamylase at 37°C and 80°C. The degree of degradation was determined by measuring the dissolved carbohydrates and the weight loss of the samples. Biodegradation was also determined by incubating the samples in a compost environment and measuring the weight loss after composting. The results indicated that the enzymatic method is a rapid means of obtaining preliminary information about the biodegradability of starch-based materials. Other methods are needed to investigate more accurately the extent of biodegradability, especially in the case of complex materials in which starch is blended with other polymers.

Effect of starch type, total β-glucans and acid detergent fiber levels on the energy content of barley (Hordeum vulgare L.) for poultry and swine

Effects of starch type, total β-glucans and ADF levels on DMD, nitrogen-corrected TME for poultry and DE for swine were evaluated in four experiments utilizing synthetic barley mixtures produced by differential pearling and milling. Forty-seven mature roosters were used in exp. 1 and 45 were used in exp. 3 to determine DMD and TME for poultry and 3 duodenally cannulated pigs were used in exps. 2 and 4 to determine DMD and DE for swine utilizing the MNBT. In exps. 1 and 2, synthetic barley (normal starch) with 11.0% ADF contained lower TME (2733 kcal kg−1) and DE (3278 kcal kg−1) compared to barley with 3.5% ADF (3371 and 3943 kcal kg−1, respectively). Increasing total β-glucans from 3.4 to 6.8% decreased TME from 3248 to 2855 kcal kg−1 and DE from 3679 to 3542 kcal kg−1. In exps. 3 and 4, there was an interaction between ADF and starch type. With normal starch, increasing ADF from 2.1 to 12.0% reduced TME from 3301 to 2630 kcal kg−1 and DE from 4018 to 3247 kcal kg−1 but with waxy starch, increasing ADF had no effect on either TME (2996 vs. 3086 kcal kg−1) or DE (3918 vs. 3712 kcal kg−1). These data suggest that the energy content of barley for poultry and swine is decreased greatly by high ADF and less by high total β-glucans, that β-glucans have a larger negative effect on energy for poultry than for swine, but that high ADF has a minimal effect on energy when barley starch is waxy regardless of the level of β-glucans. The negative effects of high β-glucans from waxy barley in exps. 3 and 4 were more apparent when the diets were low in ADF. Key words: Barley, fiber, energy, digestibility, β-glucans

Enzymatic hydrolysis of oat and soya lecithin: Effects on functional properties

AbstractEnzymatic hydrolysis of oat and soy lecithins and its effects on the functional properties of lecithins were investigated. The phospholipase used was most efficient at low enzyme and substrate concentrations. More fatty acids were released from soy lecithin than from oat lecithin. The maximum degree of hydrolysis was 760 μmol free fatty acids per gram soy lecithin and 170 μmol free fatty acids per gram oat lecithin. On the basis of the total carbohydrate and phosphorus contents in the polar fractions of the lecithins, oat lecithin contained more glycolipids and less phospholipids than soy lecithin. With regard to functional properties, the stability of oil‐in‐water emulsions was enhanced by hydrolyzed soy lecithin and by crude and hydrolyzed oat lecithins, but only hydrolyzed soy lecithin prevented the recrystallization of barley starch. The dissociation enthalpy of amylose‐lipid‐complex (AML‐complex) was significantly higher when hydrolyzed soy lecithin was present. Hydrolyzed oat lecithin slightly affected the dissociation enthalpy of AML‐complex. The other lecithins had no effect on recrystallization or dissociation enthalpies in the barley‐starch matrix.

Hydrolysis of Barley Starch Granules by α-Glucosidases from Malt

Abstract Two α-glucosidases were prepared from malt and were shown to be free of alpha -amylase and limit dextrinase activity. A mixture of large and small starch granules isolated from barley seed was treated with high (G1) and low (G2) pI α-glucosidase, purified alpha -amylase 1 and 2 and a combination of each enzyme. Samples were taken during the digestion and analysed for soluble carbohydrate, glucose and reducing sugar production. Granule morphology was assessed by scanning electron microscopy. α-Glucosidases were found to hydrolyse intact starch granules but at a lower rate than an equivalent α-1,4 bond hydrolysing activity of alpha -amylase. There was some synergism between G1 and the α-amylases in the hydrolysis of starch granules that exhibited larger and more numerous holes on their surfaces. An additive effect on granule degradation was observed for G2.

Amylose Content and Chain Profile of Amylopectin from Normal, High Amylose and Waxy Barleys

AbstractThe amylose content and the chain profile of amylopectin from normal, waxy and high amylose barley starches were determined after enzymatic debranching and gel permeation chromatography and the degree of branching of the amylopectin was analysed by 1H‐n.m.r. spectroscopy. The normal barley starch contained around 30%, the high amylose around 40% and the waxy starch 9% amylose. The amylopectin of the high amylose starches had longer chains than those of the normal or waxy starches, especially in the molecular weight interval 5,400‐8,000, but less of those below 2,400 in molecular weight. The chain length of amylopectin from high amylose barley was on average 5 units longer than those of normal or waxy barleys.

Resistance to acid hydrolysis of lipid-complexed amylose and lipid-free amylose in lintnerised waxy and non-waxy barley starches

Waxy barley starches (0.8–4.0% lipid-complexed amylose = L·AM, 0.9–3.4% lipid-free amylose = F·AM) and non-waxy barley starches (6.1–7.2% L·AM, 23.1–25.9% F·AM) were lintnerised by steeping in 2 M HCl at 35°C for 140 h. Material solubilised from the waxy starches was estimated to be 70.7% of their amylopectin (AP) plus 3.7% of their L·AM and F·AM, and material solubilised from the non-waxy starches was estimated to be 70.7% of their AP plus 28.9% of their L·AM and F·AM. The polysaccharide components of the insoluble residue were characterised by HPLC, GPC, and λ max of the polyiodide complex. I was concluded that short chain-length (CL 16) material was from external chains of AP, intermediate material (modal CL 46) was from retrogated F·AM, and longer chain residues (CL 77, 120–130_ were from lipid-complexed segments of L·AM. The starch lysophospholipids were completely hydrolysed to free fatty acids which remained complexed with L·AM residues. This was shown by the 13C CP/MAS-NMR spectrum which had a clear resonance at 31 ppm from mid-chin methylene carbons of fatty acids in complexes. The C-1 signal of the L·AM residues also included a feature at 104 ppm indicative of single V 6 AM helices. The wide-angle X-ray diffraction patterns of the residues of non-waxy starches were Cc-type ( = mixed A + B types), whereas the spectra of the original starches were A-type. It is suggested that, during the early stages of lintnerisation, amorphous (F·AM was partially hydrolysed into material (CL < 120) that retrogated into double helices (with B-type crystallinity) that were resistant to hydrolysis. Evidence for some B-crystalline polymorph was also obtained from the 13C CP/MAS-NMR spectra, which were consistent with a mixture of double helices and V-type glycosidic conformations, with only a small proportion of non-ordered regions. Broad DSC endotherms were found for both waxy (50–110°C) and non-waxy (50–110°C) lintner residues, which were assigned to disordering of double helices from short chains (modal CL 16) for waxy residues, together with disordering of longer chains (modal CL 46) in double-helix residues of F·AM and also V-helix residues of L·AM for non-waxy starch residues.

Cereal grain digestion by selected strains of ruminal fungi.

The ruminal fungi Orpinomyces joyonii strain 19-2, Neocallimastix patriciarum strain 27, and Piromyces communis strain 22 were examined for their ability to digest cereal starch. All strains digested corn starch more readily than barley or wheat starch. Orpinomyces joyonii 19-2 exhibited the greatest propensity to digest starch in wheat and barley, whereas the digestion of these starches by N. patriciarum 27 and P. communis 22 was limited. Media ammonia concentrations were lower when fungal growth was evident, suggesting that all strains assimilate ammonia. Fungi formed extensive rhizoidal systems on the endosperm of corn, but O. joyonii 19-2 was the only strain to form such systems on the endosperm of wheat and barley. All strains penetrated the protein matrix of corn but did not penetrate starch granules. Starch granules from all three cereals were pitted, evidence of extensive digestion by extracellular amylases produced by O. joyonii 19-2. Similar pitting was observed on the surface of corn starch granules digested by N. patriciarum 27 and P. communis 22, but not on wheat and barley starch granules. The ability of ruminal fungi to digest cereal grains depends on both the strain of fungus and the type of grain. The extent to which fungi digest cereal grain in the rumen remains to be determined.

Accessibility of Barley Starch Granules to α-Amylase during Different Phases of Gelatinization

The effect of the degree of gelatinization of barley starch granules on their accessibility to α-amylolysis was studied. The limited ability of Bacillus licheniformis and porcine pancreatin α-amylases to hydrolyse raw barley starch was reflected in the small release of soluble carbohydrates during α-amylolysis at 30°C. Annealing of starch for 3 hours below 50°C did not increase enzymic accessibility. At the higher pre-heating temperatures of 55 and 60°C, the amount of solubilized carbohydrates increased during subsequent α-amylase treatment at 30°C. The increase in enzymic accessibility could well be explained by the reduced order and crystallinity of starch, which was also detected by thermal analysis. The first change observed in the molecular size distribution of α-amylase-treated barley starch granules was detected as a decrease in the amylopectin moiety only after pre-heating at a temperature of 50°C or higher. The α-amylolysis at 30°C increased the solubility of the residual starch granules at 85°C.

Modification of barley starch by α-amylase and pullulanase

The hydrolysis of the amylopectin of gelatinized waxy barley starch by Bacillus licheniformis α-amylase occurred in a non-random way, showing accumulation of smaller-size hydrolysis products. The hydrolysis of barley starch by Bacillus acidopullulyticus pullulanase also began with a rapid decrease in the molecular size of amylopectin, indicating that the enzyme was capable of hydrolyzing the α-1,6-linkages in the middle of the amylopectin molecule.

Effect of the protein matrix on the digestion of cereal grains by ruminal microorganisms.

Experiments were conducted to investigate the role of the protein matrix in the digestion of barley and corn by ruminal microorganisms. Grains, ground and collected on sieves as two particle fractions .25 to .89 mm (small particles) and 2.00 to 3.00 mm (large particles), as well as isolated barley and corn starch granules, were incubated with ruminal inocula. For both grains, digestion of starch in small particles was greater (P < .001) than that of large particles. At 16 and 24 h starch digestion was greater (P < .01) in barley than in corn, for small and large particles. Digestion of barley starch granules did not differ (P > .05) from that of corn starch granules at any incubation time. A 4-h preincubation of small-particle corn and barley with protease increased (P < .001) microbial digestion of starch in corn at 16 h but did not affect digestion of barley. When four ruminally cannulated steers were fed diets containing 80% barley, corn, or wheat or 100% alfalfa hay in a 4 x 4 Latin square experiment, amylolytic activity of ruminal inoculum was higher for steers fed grains than for those fed alfalfa. However, when standardized for total viable counts of bacteria, ruminal amylolytic activity did not differ (P > .05) among diet treatments, but proteolytic activity of ruminal inoculum for steers fed alfalfa was higher (P < .01) than that for steers fed cereal grains. Activity of serine proteases in ruminal inoculum was higher (P < .05) for steers fed alfalfa than for steers fed grains.(ABSTRACT TRUNCATED AT 250 WORDS)