Comparison of Size Characterization of Barley Starch Granules Determined by Electron and Optical Microscopy,Low Angle Laser Light Scattering and Gravitational Field-Flow Fractionation

Several methods were used for the characterization of starch granules isolated from barley kernels. A procedure based on a combination of alkaline digestion, toluene treatment and filtration over sieves with pore diameters of 70 and 40 μm was used for isolation and purification of starch granules from kernels. The released starch granules were characterized by various methods: scanning electron microscopy (SEM), image analysis of optical microscopy data (IAOM), low angle laser light scattering (LALLS), and gravitational field-flow fractionation (GFFF). All methods showed the bimodal size distribution of the isolated starch granules, however, they differed in the ratio of large and small starch granules. LALLS and GFFF were also used for determination of the ratio of large and small starch granules (ratio A/B) isolated from two malting barley cultivars Kompakt and Akcent. Both techniques determined the higher ratio A/B for the cultivar Akcent. SEM was also used to examine the extent of digestion. The micrographs indicate that a significant proportion mainly of small granules are still embedded into residues of endosperm and a more extensive digestion must be performed to release all starch granules from barley kernels.     

Monitoring of barley starch amylolysis by gravitational field flow fractionation and MALDI-TOF MS

BACKGROUND: In barley, starch occurs in the form of granules with bimodal size distribution. Enzymatic hydrolysis of the starch granule is one of the most important reactions occurring during malting and mashing. Previous studies revealed the discrepancies in the assumption that barley varieties with better malting qualities should have a higher A/B (large/small starch granules) ratio. This led us to focus our attention on detailed analysis of two barley varieties, Jersey and Tolar, both with high malting quality but significantly differing in A/B (1.28 and 0.66, respectively), were chosen for more detailed analysis in the actual work. In this study, the capacity of gravitational field flow fractionation (GFFF) to monitor amylolysis of the starch granules was investigated. RESULTS: Isolated starch granules from these two barley cultivars were treated with amylases. The changes in starch granule size and bimodal distribution were studied by GFFF. Simultaneously, free sugars released during enzymatic digestion were observed by matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry. The changes in the fractogram and in the mass spectra reflect a correlation with the progress of enzymatic hydrolysis. CONCLUSION: The results show the interest in utilization of GFFF as a simple and cheap method for monitoring changes in the distribution of the starch granule size during amylolysis. Copyright © 2011 Society of Chemical Industry     

Variation in Minnesota HRS wheats: starch granule size distribution

The functional properties of wheat (Triticum aestivum L.) starch, which are responsible for the unique characteristics of many foods, can be in part explained by variations in starch granule sizes. This study characterizes the variation in starch morphology in Minnesota Hard Red Spring wheats and examines the interdependence of the granule size distribution on selected mixing and pasting properties. Starch granule sizes were measured using an automated microscopic imaging instrument in both wheat-meal and flour, and these data were correlated with their respective mixing and pasting properties. Quantitative image analysis showed significant differences (Tukey HSD, P<0.025) in the mean percentage of wheat-meal large starch granules (>10 μm in diameter) among five varieties commonly grown in Minnesota. The proportion of large starch granules also correlated significantly with the pasting properties of wheat-meal and flour, whereas the proportion of starch granules below 10 μm in diameter correlated significantly to the wheat-meal and flour mixing properties.     

Starch Granule Size Distribution in Grains at Different Positions on the Spike of Wheat (Triticum aestivum L.)

The present study was carried out to characterize the effects of soil water status, cultivar and grain position on starch granule size distribution. The starch granule size distribution and protein and starch content were determined from three wheat cultivars with reference to the position of the grain on the spike. The results showed that the contents of A‐, B‐ and C‐type starch granules were affected by soil water, genotype and soil water×genotype interaction. Grain position was significant for A‐ and C‐type starch granules. Genotype×grain position and soil water×genotype×grain position interactions only affected C‐type starch granules. Both basal and distal grains on middle spikelets contained three types of starch granules: smaller C‐type granules with diameters <2.0 μm, medium B‐type granules with diameters 2.0–9.8 μm and large A‐type granules with diameters >9.8 μm at maturity. Both percent volume and percent surface area distribution of starch granules in basal grains showed the typical three populations, and those in distal grains exhibited a two‐peak curve. The volume and surface area percentage of C‐type granules and protein content in basal grains were higher than that in distal grains, but those of A, B‐type granules in basal grains were lower than that in distal grains. Compared with irrigation, the percent volume and surface area of B, C‐type starch granules and protein content in basal and distal grains were significantly increased, and those of A‐type were evidently decreased in rainfed condition.     

Enzymic Extraction of Native Starch from Sago (Metroxylon sagu) Waste Residue

Residual native starch was extracted from sago pith residue using two types of commercial cell‐wall degrading enzymes, Pectinex Ultra SP‐L and Ultrazyme 100G. The first increased starch yield with a shorter incubation period than the second. The superior effect of Pectinex Ultra SP‐L was observed already at 0.5 h, where a wide granule size distribution (8—87 μm) was obtained. A slight increase in the release of granules ranging from 30—60 μm was noted within a 2 h incubation period. However, upon further incubation, the distribution pattern was similar to that of untreated samples. Samples treated with Ultrazyme 100G exhibited a unimodal distribution pattern, with larger granules, ranging from 40—70 μm, being released upon further incubation within a 2 h incubation period. However, all samples exhibited a bimodal distribution upon further incubation.     

Granule Sizes of Canna (Canna edulis) Starches and their Reactivity Toward Hydration,Enzyme Hydrolysis and Chemical Substitution

Small and large granule fractions were isolated from canna starch (Canna edulis, green leaf cultivar), and their morphology, physicochemical properties, susceptibility towards granular starch hydrolyzing enzymes and chemical reaction with propylene oxide were investigated. Canna starch consisted of a mixed population of large, medium and small granules; the mean of granule diameter was 47.4 μm. The small granules presented round and polygonal shapes, whereas the large granules had oval and elliptical shapes. Significant variations in digestibility of the various granules size by granular starch hydrolyzing enzymes were observed. During the first 24 h, the hydrolysis rate of small granules was higher than that of native and large granule starches. After 72 h, however, the degree of hydrolysis of small granule, large granule and native starches had reached the extent of 19.6%, 32.0% and 27.2%, respectively. The larger the granule size, the higher the MS obtained when modified with propylene oxide, which was due to the higher swelling power of the large granules. The results obtained from this study suggest that small granules had lower water and chemical affinity when compared with the bigger ones. The difference in the reactivity of small and large granules could be presumably attributed to the starch components (amylose and amylopectin) and their organization of glucan chains in ordered and/or less ordered structure of these two fractions.     

醇水相湿热处理对玉米淀粉颗粒性质的影响

采用醇水相湿热处理对玉米淀粉进行研究,考察了处理温度范围为70-90 ℃内淀粉颗粒偏光十字,形貌,粒径分布,结晶结构及糊性质等性质变化。随着湿热处理温度升高,发现：淀粉颗粒偏光十字消失增多,最终颗粒破碎;颗粒平均粒径由23.6 μm持续增加至50.4 μm,其中小颗粒（〈10 μm）数目减少,中等颗粒（10-30 μm）和大颗粒（30-100 μm）数目均有不同程度的增加;淀粉颗粒表面出现小孔和凹坑,最终颗粒成团,干燥粉碎之后破碎成片状;淀粉的X射线衍射在衍射角15°,18°和23°处峰强度逐渐降低,但在衍射角20°处峰强度增加。淀粉的Brabender粘度曲线显示,湿热处理后玉米淀粉糊化起始温度由80.5 ℃升高至90.6 ℃,粘度降低,表明玉米淀粉热糊稳定性和冷糊稳定性增强,糊凝沉性降低;测定分析淀粉分子量可知,淀粉颗粒内部分子链发生了断裂、降解。     

Characterisation of starches from West African yams

Starches from four varieties of West African yams were extracted and characterised. The physicochemical properties investigated (granule size and morphology, amylose content, crystal form, gelatinisation and pasting behaviour) depended strongly on the yam variety. The starch granules extracted from water yam (Dioscorea alata), white yam (D rotundata) and yellow yam (D cayensis) varieties showed mononodal particle size distributions centred between 31 and 35 µm, while the bitter yam (D dumetorum) exhibited a binodal size distribution of starch granules centred at 4.5 and 9 µm. Light microscopy confirmed the variation in starch granule size and shape with yam variety. The X-ray diffractogram of yellow yam was of the B type, while bitter yam showed an A pattern. The starches extracted from the white and water yams were of the intermediate C-type patterns. The temperatures of onset of gelatinisation were derived from DSC and RVA measurements; values of 69.4 and 75.0 °C for the yellow yam, 71.5 and 78.2 °C for the white yam, 76.5 and 79.8 °C for the water yam and 78.1 and 83.1 °C for the bitter yam were obtained. © 1999 Society of Chemical Industry     

Effect of temperature on the synthesis,composition and physical properties of potato microtuber starch

Potato microtubers (cv Maris Piper) were grown at 10, 16 and 24°C in total darkness for 28 days. Soluble and insoluble starch synthase, ADPglucose pyrophosphorylase, sucrose synthase and fructokinase were assayed in extracts of the microtubers and, in the case of soluble and insoluble starch synthase, activity was found to be particularly sensitive to increasing growth temperature. The starch content of the microtubers increased slightly with increasing growth temperature, but with little effect on the number of granules per microtuber and a small increase in the average granule size. The microtuber starch granules were much smaller than those found in commercial potato starch (c 8–9 μm modal diameter compared to c 21 μm). Although the amylose content of the microtuber starches tended to increase with increasing growth temperature, the phosphorus content was variable. Gel permeation chromatographic elution profiles of native and debranched microtuber and a commercial potato starch showed that no differences could be detected in either amylose or amylopectin molecular size, polydispersity or unit chain distribution of amylopectin (which contained two major unit chain fractions at DP 21 and 56). The onset, peak and conclusion temperatures of the DSC gelatinisation endotherm increased linearly as a function of growth temperature whilst the enthalpy of gelatinisation decreased. It is suggested that elevated temperature during starch biosynthesis facilitates ordering of amylopectin double helices into crystalline domains. © 1998 SCI.     

Structure,functionality, and digestibility of acetylated hulless barley starch

Hulless barley starch was extracted and further acetylated using acetic anhydride at different level (3.75, 7.5, 11.25 g/100 g) in this study. The structure changes and functional properties of acetylated hulless barley starches comparing to the native starch were evaluated and analyzed. The shape of granules remained unaltered with cracks formed after modification. Small- (1 μm) and large-sized (20 μm) were observed in four kinds of starches while granule particle sizes distribution changed dramatically. Four hulless barley starches presented A-type x-ray diffraction pattern, with relative crystallinity of 25.6, 27.1, 26.2, and 24.8% for native and acetylated starches. The infrared ratio of 1045/1024 and 1025/995 cm^?1, indicated the difference in long-range order of crystallinities and short-range order of double helices. Results observed in swelling power, gelatinization parameters, pasting viscosities, and in vitro digestibility indicated acetylated hulless barley starch’s potential as a functional food additive and a healthy ingredient.     

Morphology and structure of chestnut starch isolated by alkali and enzymatic methods

The structure and morphology of starch from fruits of two chestnut (Castanea sativa Mill.) varieties, Martainha and Longal, isolated by alkaline (A3S) and enzymatic (ENZ) methods were assessed. Chestnut starch granules were found to be round and oval in shape, consisting of medium/small granules, with a mean granule size ranging between 9 and 13 μm. Isolated chestnut starch appeared to the naked eye as a white powder, with high values of L^∗, and the Longal variety produce starches duller than Martainha. No differences between samples were observed by FTIR analysis. The X-ray patterns of isolated starches are of C-type (more specifically of C_b type) with a relative crystallinity between 31.5% and 39.8%. The ¹³C CP/MAS NMR spectra are similar for both varieties but different for the used isolation methods. The amorphous phase in the starch granules isolated by A3S methods was lower than that of the starch extracted by the ENZ method, making the B-type allomorph in the C-type starch granules more evident than in the A-type. Those differences in the structure of isolated starches are shown by a lower degree of damage, and a higher level of crystallinity of starches isolated by the A3S method, which means that its original structure is less affected or partially destroyed. This study would be helpful to better understand the relationships among structure and functional properties for a eventual industrial application of chestnut starches.     

Isolation, Partial Characterization and Modification of the Great Northern Bean (Phaseolus vulgaris L.) Starch

The yield of the Great Northern bean starch was 18.23% (bean flour basis). The starch granule size ranged from 12 × 12 μm to 58 × 40 μm (length × width). The shape of starch granules was round to oval to elliptical, and in some cases, concave as well. Lamellae were present on all the starch granules observed. Amylose content of the starch was 10.2% (starch basis). Hog pancreatic α-amylase hydrolyzed more starch than did malt α-amylase under similar conditions. The Great Northern bean starch had good water and oil absorption capacities at room temperature (21°C). The bean starch formed a stable gel at concentrations of 7% and above (w/v). The viscoamylographic studies of the isolated starch indicated the restricted-swelling character of the bean starch.     

Effect of wheat puroindoline alleles on functional properties of starch

Puroindoline a and b (Pina, Pinb) form the molecular basis of bread wheat grain hardness. Varieties with a softer endosperm and a wild genotype, in which both Pina and Pinb were present, seemed to produce less damaged starch flour than hard varieties, where Pin mutations occurred and changed the starch rheological properties. The functional property of starch samples extracted from wheat varieties with different Pin alleles was evaluated. Starch morphology was characterized by scanning electron microscopy and laser light scattering. Thermal properties were evaluated by differential scanning calorimetry. Amylose content, starch damage and rapid visco-analyser (RVA) parameters were also determined. Significant variations (P < 0.05) were identified between different Pin variants for the distribution pattern of starch granule volume, amylose content, starch damage, RVA viscosity breakdown and retrogradation, gelatinisation transition temperatures and enthalpies. Hard genotypes presented higher medium diameter granules and lower enthalpic values. However, the differences detected are more evident among varieties that present both Pina and Pinb, than among those presenting only one of the two (a or b).     

Physicochemical and Biochemical Characterization of Starch Granules Isolated of Pigmented Maize Hybrids

In this study, the morphological and physicochemical of pigmented maizes as well as the initial characterization of the corresponding starch granule enzymes are described. Starch granules were isolated from blue, black, and white maize. They were analyzed using scanning electron microscopy, particle size distribution, pasting characteristics, sorption isotherms, differential scanning calorimetry, and two‐dimensional gel electrophoresis. The morphology of the starch granules of pigmented maizes was different from the granules of white maize; the pattern was related to the endosperm type of these varieties. The average starch granule size was higher for black than for white and blue maizes. The average gelatinization temperature was similar in the three starches, but the pigmented maizes had higher gelatinization enthalpy; black maize starch showed the lowest enthalpy of retrogradation. These results indicated that the starches from the three maizes analyzed had different organization level. Black maize starch showed the highest peak viscosity followed by white and blue maize starches. In the gel electrophoresis three starch granules presented one main spot at pI of 5 and MW of 60 kDa that corresponds to the granule‐bound starch synthase. Blue and white starches presented some spots near 97 kDa at pI of 5.3–5.7 (white maize) and 5.1–5.5 (blue maize), spots that were not observed for black maize starch. The morphological and physicochemical characteristics of maize starch are related to the enzymes involved in its biosynthesis.     

Air classification of flours of three legume species: Effect of starch granule size distribution

The effect of starch granule size distribution on separation behaviour of whole starchy grain legume flours during air classification was studied, using laboratory-scale equipment and two varieties each of cowpea (Vigna unguiculata), faba bean (Vicia faba) and pigeonpea (Cajanus cajan). Cut points at a range of classifier settings were calculated from particle-size analysis of the fines and coarse fractions using a Coulter counter. The whole flours varied considerably in starch granule size distribution between species and varieties. Cowpea, which contained a high proportion of small starch granules, yielded fines with a higher starch content and a greater dry weight yield than the other species studied.     

红缨子高粱淀粉分子结构及糊化特性研究

分别采用扫描电镜、X射线衍射及傅立叶变换红外光谱（FTIR）分析茅台酒酿造专用高粱红缨子淀粉的颗粒结构,采用离子色谱分析其支链淀粉链长分布特征,采用差示扫描量热仪、快速黏度仪及流变仪分析其淀粉糊化特征。结果表明,红缨子高粱淀粉颗粒大小介于5～20 μm,部分颗粒表面有凹陷或呈蜂窝状;淀粉颗粒晶体结构为A型,结晶度为31.0%,淀粉颗粒表面结构的有序性比水稻、马铃薯等其他淀粉高;支链淀粉含有较高的fb3长链组分;在低温及高频率条件下,其动态模量相对较高;另外,红缨子高粱淀粉拥有较高的糊化温度和糊化吸收热焓值,具备高崩解值和低回生值等适宜酿酒的重要特征。     

Properties of starches of some West African yams

The tuber starches of several species and varieties of yam (Dioscorea) grown as food crops in West Africa were examined. The granule sizes were investigated, and the forms of the starch granules are illustrated in photographs. Amylose contents were also measured, together with ‘pasting temperatures’, viscous properties and gel strength. The granules of D. rotundata and D. alata were large (10–70 μ) while those of D. esculenta and D. dumetorum were much smaller (1–5 μ). The starch of D. rotundata gave the most viscous solutions, but that of D. alata gave the strongest gel. Pasting temperatures ranged between 76° and 85°.     

Ghosts of B‐type Wheat Starch Granules in Concentrated KI/I2 Solution

When B‐type (2.0–8.0 µm) wheat starch granules containing various amounts (2.1–25%) of amylose were treated with 25% KI/10% I₂ solution, low‐amylose (below 10% amylose) B‐type wheat starch granules changed to the ghost form. It is known that A‐type (25–35 µm) wheat starch granules change to the ghost form and show a typical double structure (a black‐brown central portion and red‐brown surrounding portion), however, the B‐type wheat starch ghosts did not show the same double structure but rather a simple (red‐brown portion) sack form. The relative ghost areas in the B‐type wheat starch granules were highly correlated to the amylose content (%), which was similar to the results of A‐type starch granules. This suggests that the amylose molecule in B‐type starch contributes to the structural stability of the starch granule.     

Starch Granule Size Strongly Determines Starch Noodle Processing and Noodle Quality

Chemical compositions, physical properties, and suitability for starch noodle making of different granule size fractions from potato and sweet potato starches were studied. The ash content, amylose content, phosphorus content, gel firmness, and freeze‐thaw stability of small‐size granule fractions(< 20 μm) were significantly different from those of the large‐size granule fractions. The processibility and the qualities evaluated by objective and subjective methods of both dried and cooked starch noodles made from small‐size granule fractions were significantly better than those made from their initial starch preparations and much better than those made from the large‐size granule fractions.     

The size distribution of starch granules in endosperm of different sized kernels of the wheat cultivar maris huntsman

The particle size distributions of starches prepared by proteolysis from different sized kernels of Maris Huntsman wheat, were determined by Coulter Counter. The number of starch granules was greater in “large plump” kernels than in “small plump” and “shrivelled” kernels grown under the same conditions. In all three kernel types more than one third of the total starch weight was contributed by granules less than 10 μm diameter (B type granules). The proportion of these small granules was significantly greater in “large plump” kernels than in the other two types.