The Pasting Characteristics of Various Sizes of Starch Granule from Wheat

Starches, of contrasted pasting properties from two bread wheat cultivars, were fractionated on the basis of granule size. Differences in starch hot-pasting characteristics were observed mainly between large A-granule fractions (diameter about 23 μm) of the two starches. Less pasting differences were seen between B-granules (diameter < 10 μm) of the two starches. Examination of immature starches suggested that pasting differences between A-granules were established during the period of A-granule early growth, within about 15 days of fertilization, rather than during the later period of grain filling and desiccation. Granule size distribution itself did not determine the differences observed.     

Effect of gamma‐ray irradiation on the physicochemical properties of flour and starch granule structure for wheat

Effect of gamma irradiation on the physicochemical properties of flour and starch granule structure of wheat was compared to non‐irradiated wheat. The moisture content of wet gluten and titratable acidity of wheat flour were significantly affected by gamma irradiation. This treatment also destroyed the starch granules of wheat grain and their breakage augmented as the dose of gamma irradiation increased, apparently resulting in the increase of small starch granules. Probably, these results were due to the disruption of large molecule, such as proteins, lipids and starch. The irradiated wheat flour for RVA pasting properties (flour viscosity) was also evaluated. Besides the difference in RVA profile, starch pasting curves showed a considerable decrease for six main parameters as gamma irradiation dose at different velocity increased.     

Effects of size of cellulose granules on dough rheology, microscopy, and breadmaking properties

ABSTRACT:  Breadmaking was performed with cellulose-blended wheat flour. Cellulose granules (7 types) of various sizes (diameter) were prepared by kneading. With increase of the blend percent of the cellulose samples from 10% to 20%, breadmaking properties such as bread height and specific volume (SV) gradually decreased in every sample; however, the decreasing levels of the properties in 7 types of various sizes varied. The decrease of bread height and SV was associated with the size of the cellulose granule. It was observed at both 10% and 20% blends that the same bread height and SV as for bread baked with only wheat flour could be obtained when the diameter of cellulose granule was above 154 μm in cellulose/wheat flour breadmaking, while they gradually decreased with granules below 154 μm. When the largest cellulose granules were mechanically ground to make smaller ones, the bread height and SV decreased with increasing grinding time. It was ascertained that the size of the cellulose granule was important for breadmaking properties. Cellulose-blended wheat flour was subjected to mixograph tests. When cellulose granules above 154-μm dia were blended with wheat flour, the profile of the mixogram was almost the same as that for wheat flour; that is, the profile had a short mixing requirement and showed a viscous gluten matrix. However, when cellulose granules below 81-μm dia were blended, a different curve showing a nonviscous dough due to breakdown of the gluten protein was observed, as ascertained by microscopy. Farmograph test showed that the amount of the released gas from cellulose-blended bread dough increased with decrease of the size of the cellulose granule due to breakdown of the gluten protein.     

Effect of industry-scale microfluidization on structural and physicochemical properties of potato starch

A recently designed “industry-scale microfluidizer” (ISM) was applied to treat potato starch, then the structural and physicochemical properties of potato starch treated at different ISM pressure (30, 60, 90, and 120 MPa) were investigated. As ISM pressure increased, starch granule size was firstly increased, and subsequently declined at 120 MPa. A remarkable destruction of starch granules was observed, and all the large granules disintegrated into irregular block-like structures after treatment at 120 MPa. Both crystalline and short-range ordered structure were progressively disrupted with the increase of pressure. The structural destruction was attributed to starch gelatinization, which depended on ISM pressure. ISM treatment could arbitrarily adjust pasting viscosity and increase setback value of potato starch. Moreover, moduli and mechanical rigidity of starch pastes were enhanced by ISM treatment. These results implied that ISM treatment could be a potential choice to modify starch containing large granules at an industrial level.Industrial relevanceMicrofluidization was an available physical technique to improve functional properties of starch. However, it was difficult for conventional microfluidizer to treat starch containing big granule sizes both in laboratory and industrial scale owing to the drawbacks of devices. A recently designed “industry-scale microfluidizer” (ISM) in our laboratory could be applied to treat potato starch containing large granules. This preliminary study gave important indications that the practical industrial applications of potato starch could be widen by safe and simple microfludization technology, and ISM may be used for processing whole grains flour to obtain nutritional products.     

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°.     

Physicochemical Properties and Starch Granular Characteristics of Flour from Various Manihot Esculenta (Cassava) Genotypes

ABSTRACT: Flour and starch were produced from 11 cassava genotypes. Starch and total dietary fiber contents were determined using a single-enzyme gravimetric procedure and high-performance anion exchange chromatography, pasting profiles by rotary viscometry, water holding capacity gravimetrically, and granular characteristics by scanning electron microscopy. Starch and total dietary fiber contents varied among genotypes. Flour peak viscosities, setback, and final viscosities differed significantly. Flour water holding capacity correlated with flour peak viscosity (r = 0.7). Starch granules ranged from 9 to 20 μm. Predominant granule shapes were oval, rounded, and truncated. The results provide insights into cassava genotype characteristics, and functionality of cassava starch and flour.     

Starch from hull-less barley: I. Granule morphology,composition and amylopectin structure

Starch was extracted from 10 hull-less barley (HB) genotypes [waxy (CDC Candle, CDC Alamo, SB 94912, and SB 94917), normal amylose (Phoenix, CDC Dawn, SR 93102, and SB 94860), and high amylose (SB 94893 and SB 94897)]. Starch content ranged from 56 to 65%. The purity of the isolated starches was greater than 96%. Average starch yield and extraction efficiency were 44 and 71%, respectively. The starches from all genotypes consisted of a mixture of large lenticular and small irregularly shaped granules. The granules of most starches were intact, whereas in others (SB 94917, SR 93102, and SB 94860) they were compound (clustered). The proportions of small (diameter⩽10 μm) and large granules (diameter>10 μm), by total number and by total weight differed among genotypes. Bound lipid content was positively correlated (r=0.92, P<0.01) with total amylose content. Free and bound lipid contents ranged from 0.1–0.3% and 0.3–1.7%, respectively. The apparent and total amylose contents ranged from 0–39% and 0–45%, respectively. The amounts of amylose complexed with native lipids (total amylose–apparent amylose) ranged from 0.5 to 7.8%. The proportion of small granules was correlated with total amylose content (r=0.59, P<0.1). However, the average granule diameter was negatively correlated (r=−0.65, P<0.05) with total amylose content. The debranched amylopectins of all starches exhibited the highest peak in the MALDI-MS spectrum at DP 12. The average chain length (CL) and degree of branching ranged from 17.6–22.7% and 4.4–5.5%, respectively. The short (DP 5-17) and long (DP⩾35) chains ranged from 58.2–59.1% and 3.0–12.8%, respectively. The study showed that amylose/amylopectin ratio and amylopectin branch chain length have high correlation with granule size and size distribution in this set of barley genotypes.     

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.     

Studies on Oat Starch with a Celloscope: Granule Size and Distribution

Detailed granule size distribution in oat starch was determined with a Celloscope. Maximum granule number appeared at a diameter range of 1.9-2.4 μm and corresponding maximum volume was at 6.0-7.6 μm. In light of the observed high reproducibility of the Celloscopic technique it was concluded that no aggregation of individual granules occurred at concentrations below 1 mg/ml. The Celloscopic data based on direct counting of granules as a function of their shape-independent volume. It could be demonstrated that two different average granule sizes, 3.0 and 6.4 - 7.4 μm, can be obtained depending on whether the sizings are based on estimation of the granule's cross-sectional areas or directly the effective volumes. Only the latter approach was capable of revealing variety-specific differences in the average granule masses. For rapid starch sizings of samples containing granules from any of the size ranges within the distribution diagram a rapid “coarse” counting method was developed.     

Morphological and starch characteristics of the <Emphasis Type="Italic">Japonica</Emphasis> rice mutant variety Seolgaeng for dry-milled flour

Producing good-quality, fine rice flour is more difficult than wheat flour because the rice grain is harder. The non-glutinous Japonica-type variety Seolgaeng, derived from N-methyl-N-nitrosourea (MNU) mutagenesis, and four other varieties, representing a range of amylose contents, were evaluated in this study. Dry-milled Seolgaeng rice flour exhibited an average particle size that is <70 μm, a more uniform particle-size proportion than other varieties. Moreover, we noted significant differences in the damaged starch content in flour from Seolgaeng compared to the other varieties (p<0.05). Seolgaeng flour showed a round starch structure, which would lead to better friability, finer particle size, and less damage to the endosperm during dry milling. Indeed, among all varieties evaluated in this study, dry-milled Seolgaeng flour had the finest particle size (averaging <70 μm) and exhibited less damaged starch. With its round starch granules, Seolgaeng is a suitable candidate for drymilled rice flour.     

Effect of the milling process on quality characteristics of rye flour

BACKGROUND: Most of rye flour is obtained by a gradual reduction system using roller flour mills, which generate different flour streams. The study of the different flour streams composition is necessary since it determines the flour quality and the flour uses. Four break streams and nine reduction streams were analysed for moisture, ash, starch, protein, damaged starch, falling number, amylose/amylopectin ratio, β‐glucans and colour. Mixing and pasting properties were also determined with a doughLAB and a Rapid Visco Analyser respectively. RESULTS: As the milling process advanced, moisture and starch content decreased but protein, ash, β‐glucans and damaged starch increased. The differences in composition are probably related to the effect of the roller mills and the increase in the contamination with bran. The absorption, development time, and pasting viscosity increased as the milling proceeded, in detriment of the peak time. The β‐glucan content was positively correlated to absorption, mixing tolerance index and pasting viscosity, and negatively correlated to peak time. CONCLUSION: Differences in composition, above all, in bran, showed different mixing and pasting properties in rye streams. The most different streams corresponded to the last streams in the break process, in the sizings and in the middlings. Copyright © 2008 Society of Chemical Industry     

The physico-functional characteristics of starches from cowpea (Vigna unguiculata), pigeon pea (Cajanus cajan) and yambean (Sphenostylis stenocarpa)

Starches fractionated from cowpea (Vigna unguiculata, Ife Brown), pigeon pea (Cajanus cajan, Cita II) and yambean (Sphenostylis stenocarpa) were comparatively studied for physical and functional properties, including granule morphology, granule sizes, water absorption capacity, water–oil absorption index, swelling capacity, ionic property, bulk density and amylographic viscosities. The three legume starch granules range in diameter size from 5–57.5 μm. The water absorption capacities of all the starches were generally low at room temperature up to 70°C. Pigeon pea starch was the least susceptible to swelling while the cowpea starch was the most susceptible. The starches displayed non-ionic character, low water activity, high bulk density, water and oil absorption capacities and type C Brabender visco-amylograms at 6.2% starch-water slurry (on dry wt basis). ©     

Modified starch granules as particle-stabilizers of oil-in-water emulsions

Oil-in-water (O/W) emulsions of 20 vol% n-tetradecane have been prepared using food-compatible hydrophobic starch particulates as the primary emulsifier. As such, the systems appear to be Pickering emulsions. The starch particulates were generated from chemically cross-linked granules that do not swell on prolonged contact with water and which were made partially hydrophobic by reaction with octenyl succinic anhydride. The degree of substitution was of the order of 0.03. The size of the modified starch particulates was reduced by freezer-milling before preparing the emulsions via a jet homogenizer. Conventional light transmission microscopy, confocal laser scanning microscopy, scanning electron microscopy, multi-angle light scattering and laser Doppler light scattering all suggested that a wide range of starch particle sizes was produced. Some particles were considerably smaller than the original starch granule sizes, but a large proportion appeared to be above several microns in size. The emulsion droplets produced using 1–3 wt.% of starch as emulsifier were quite large (from approximately 1 to 20 μm in diameter), i.e., of the same order of size as a large proportion of the starch particulates. Consequently, the emulsions creamed readily, but they were extremely stable to coalescence with no significant change in the emulsion droplet-size distributions appearing for over 3 months. Further tests on the surface tensions of the homogenized and non-homogenized starch dispersions themselves confirmed the supposition that the O/W emulsions were stabilized by starch particulates and not starch molecules.     

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.     

Prediction of sweetpotato starch physiochemical quality and pasting properties using near-infrared reflectance spectroscopy

A rapid predictive method based on near-infrared reflectance (NIR) spectroscopy (NIRS) was developed to measure sweetpotato starch physiochemical quality and pasting properties. The starch samples were scanned by NIRS and analyzed for quality properties by reference methods, respectively. Results of statistical modeling indicated that NIRS was reasonably accurate in predicting amylose content (AC), amylose percent (AP), total starch content (TSC), protein content (PRC), phosphorus content (PHC), solubility (SOL), swelling power (SP), average granule diameter (AGD), big granule percent (BGP), small granule percent (SGP), crystallinity (CRY), peak viscosity (PKV), hot paste viscosity (HPV), setback (SB), and pasting temperature (P_temp) with high coefficients of determination (RSQ = 0.85–0.92) and relatively low standard errors of prediction. The results showed that NIR analysis was sufficiently accurate and effective for rapid evaluation of starch physicochemical properties in sweetpotato. The NIR-based protocol developed in this study can be used for screening large number of starch samples in food enterprises and sweetpotato breeding programs.     

Comparative analysis of starch properties of different root and tuber crops of Sri Lanka

The physicochemical properties of starches of six different root and tuber crop species grown mainly in Sri Lanka showed significant differences among the tested crop species and varieties. The median granule size of starch of tested root and tuber crop species varied from 33.5 to 10.2 μm. The largest granule size and the highest blue value were given by the canna, Buthsarana, and yam species, in that order. The amylose content of cassava was higher than those of sweet potato and many yams. High peak viscosities, high breakdown, and high final viscosities were observed in yams, and, generally, such starch showed a high swelling power. According to the correlation analysis, these pasting properties would mainly be due to their larger starch granule size. Based on the thermal properties, cassava starch showed less energy requirement for gelatinization and thus gelatinized at lower temperatures. Furthermore, a higher susceptibility of raw cassava starch toward fungal glucoamylase was observed. The low enzyme digestibility of raw yam starch would be due to its large granules. Correlation analysis showed that the blue value and starch granule size were important in determining the pasting, thermal, and other properties of starch.     

Swelling Characteristics of Native and Chemically Modified Wheat Starches as a Function of Heating Temperature and Time

The effects of hydroxypropylation (molar substitution, MS 0.05, 0.12, and 0.18) and cross‐linking (0.03%, 0.1%, and 0.2%) on swelling properties of wheat starch granules at several temperatures and heating times were investigated by laser diffraction particle size analysis. Starch samples were dispersed in water at temperatures ranging from 30 to 90°C, for 1 to 360 min. All starch granules exhibited distinct bimodal size distributions: small B‐granules with mean diameter of 2.3 μm and large A‐granules with mean diameter of 20.4 μm. As temperature increased, the B‐granules swelled more than A‐granules. Swelling of A‐granules sharply increased at 60°C. Swelling was more pronounced with increasing molar substitution of hydroxypropyl groups, while increased swelling was not observed in cross‐linked starches. The dependence of swelling capacity on heating time was different at 60 and 80°C as well as amongst modified starches. As heating time was prolonged, mean granule sizes for native, control, and hydroxypropylated starches at 80°C decreased after reaching maximum size due to loss of granule integrity, while those at 60°C showed no significant change.     

Differences in the properties of potato starch as an effect of the application of herbicides in potato cultivation

Triazine herbicides (Sencor, Bladex and Topogard) and urea preparations (Afalon, Patoran and Monorotox), used in the cultivation of four potato varieties, influenced both chemical composition and physical properties of the subsequent starch. All herbicides except Sencor caused changes in the starch granularity. Bladex increased the number of granules larger than 35 μm and the average diameter of the granules. Topogard increased the number of granules less than 10 μm and 20 μm in diameter and decreased the number of 20–35 μm granules and the average diameter of the granules. Urea preparations resulted in a decreased number of granules smaller than 20 μm, while Afalon decreased the number of granules larger than 35 μm and increased the 20–35 μm granules; Monorotox increased the number of granules larger than 35 μm and the average diameter of the granules. All herbicides decreased the viscosity of 0·25% starch pastes and Topogard decreased the amylose content of the starch.     

Granular Structure and Physicochemical Properties of Starches from Amaranth Grain

The granular structure and physicochemical properties of starches isolated from grain amaranth cultivar K112 (Amaranthus cruentus L.) were studied in this study. Detailed physical and chemical analyses were performed by determining the granular morphology, crystallinity, particle size, thermal characteristics, blue value, enzyme susceptibility, and pasting properties. Results showed polygon-shaped A. cruentus L. K112 starch granules. The average diameter was 1.38 μm, in which half of the diameter was <2.91 μm. An A-type X-ray diffraction pattern was revealed with intense peaks of 15.2°, 17.5°, and 23.2°. The peak viscosity was 181 BU and the breakdown value was 2 BU. Amaranth starch obtained the highest pasting temperature (70.7°C) and enzymatic digestibility (absorbance value = 0.41 ± 0.013) compared with corn, cassava, and sweet potato starches.     

Physicochemical properties of commercial semi-sweet biscuit

This study was performed to provide information about the physical and chemical characteristics of commercial semi-sweet biscuits and to ascertain the key characteristics of commercial semi-sweet biscuits (rich tea type), in terms of starch properties, such as gelatinisation, pasting, granule crystallinity and morphology, and to compare the magnitudes of changes of physical characteristics (diameter, thickness, weight and bulk density) for selected brands. A total of 10 rich tea biscuits from different brands were bought locally and were measured for physical and chemical characteristics. The three-point bend test showed that a biscuit with lower fat content was harder than a biscuit with normal fat content, except for sample B. Starch gelatinisation properties show that To, Tp and Tc were higher than for wheat flour whereas ΔH was lower than for wheat flour. X-ray results showed that commercial biscuits still retained their crystallinity but at lower intensities than native wheat flour. Microscopy observations revealed that some of the granule birefringence of commercial biscuits can still be observed under polarised light. Different brands of biscuits showed different physical and chemical characteristics.