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Physicochemical characteristics and fine structure of high-amylose wheat starches isolated from Australian wheat cultivars
Abstract
High-amylose starch is a source of resistant starch (RS) which have great impact on human health like dietary fiber. Nowadays, high-amylose wheat has been produced by genetic backcrossing, which enhances apparent amylose content and generates altered amylopectin. In this study, the high-amylose wheat starches isolated from various high-amylose wheat cultivars grown in Australia were characterized for understanding their physicochemical properties and fine structure of starch. The physicochemical characteristics of the high-amylose wheat starches are significantly different among the cultivars. Amylose contents of these cultivars were in a range of 28.0–36.9%, which is significantly higher than that of the normal wheat starch (25.6%). The high-amylose wheat starches also had higher blue value but lower λmax than the normal wheat starch. Gelatinization temperature of the high-amylose wheat starches is higher than that of the normal wheat starch but transition enthalpy is lower. X-ray diffraction showed that the high-amylose wheat starch had C-type crystals close to A-type crystal. Pasting properties of the high-amylose wheat starches were varying depending on the cultivars. However, almost high-amylose wheat starches had lower peak and final viscosities and higher setback viscosity than did the normal wheat starch. Fine structure of amylose and amylopectin was different among the high-amylose wheat cultivars and related to the physicochemical properties of starch. These results help to understand well the characteristics of the high-amylose wheat starches before application for food processing.
... Different breeding approaches can result in starches with increased amylose that vary in their functional, structural and thermodynamic characteristics. For example, wheat varieties with increased amylose content described by Hung, Maeda, and Morita (2007) had levels of crystallinity comparable to starches with normal amylose content, whereas another study using a different breeding strategy found increased amylose content to be accompanied with a loss of crystallinity (Hung, Maeda, Miskelly, Tsumori, & Morita, 2008). ...
... The varieties used in this study, and those described by Blazek and Copeland (2008) and Hung et al. (2008), were obtained by genetic back-crossing of wheat cultivars grown in Australia. The swelling power test was used as a simple screening method to select lines for increased amylose content; hence, the genetic background of these wheat cultivars was not uniform. ...
... The swelling power test was used as a simple screening method to select lines for increased amylose content; hence, the genetic background of these wheat cultivars was not uniform. These starches have been shown to have a gradation of pasting, swelling and thermodynamic characteristics correlated to amylose content (Blazek & Copeland, 2008;Hung et al., 2008). In this study, SAXS together with DSC, XRD and fluorophore-assisted capillary electrophoresis, were employed to further examine structural features that provide these starches with a wide range of functional properties within a narrow range of enriched amylose content. ...
Small-angle X-ray scattering (SAXS) together with several complementary techniques, such as differential scanning calorimetry and X-ray diffraction, have been employed to investigate the structural features that give diverse functional properties to wheat starches (Triticum aestivum L.) within a narrow range of enriched amylose content (36-43%). For these starches, which come from a heterogeneous genetic background , SAXS analysis of duplicate samples enabled structural information to be obtained about their lamellar architecture where differences in lamellar spacing among samples were only several tenths of nanometer. The SAXS analysis of these wheat starches with increased amylose content has shown that amylose accumulates in both crystalline and amorphous parts of the lamella. Using waxy starch as a distinctive comparison with the other samples confirmed a general trend of increasing amylose content being linked with the accumulation of defects within crystalline lamellae. We conclude that amylose content directly influences the architecture of semi-crystalline lamellae, whereas thermodynamic and functional properties are brought about by the interplay of amylose content and amylopectin architecture.
... The exhibition of larger final viscosity and setback value may be responsible for a huge tendency for retrogradation in food products during storage [4], whereas the high-setback rice flour provides more food structure. This rice flour property is appropriately recommended for fried snacks, stick rice noodles, and pasta noodles [37]. The results from pasting properties indicate that RD43 rice flour may be more enhance the structure of food products than Hom Mali rice flour. ...
... Foods 2020, 9, x FOR PEER REVIEW 10 of 15 food structure. This rice flour property is appropriately recommended for fried snacks, stick rice noodles, and pasta noodles [37]. The results from pasting properties indicate that RD43 rice flour may be more enhance the structure of food products than Hom Mali rice flour. ...
... Also, the amylose-lipid complex may influence pasting properties by increasing the hydrophobicity of starch granules, resulting in an increase in granule swelling and amylose leaching [36]. Consequently, this interaction causes a reduction of peak and breakdown viscosity and an increase in setback and final viscosity [36,37]. In addition, storage time, temperature during milling process, and environment are other factors on different pasting properties of the rice flour [40][41][42]. ...
The increased use of a new rice cultivar is the result of increasing consumer demands for healthier choices. In this study, physicochemical, thermal, pasting, and functional properties of flour from RD43 rice, a new rice variety, and its food application were investigated. RD43 rice flour demonstrated an irregular and polyhedral shape with a volume mean diameter of 103 ± 0.15 µm. In addition, the amylose content of RD43 rice and Hom Mali rice flour was 19.04% and 16.38%, respectively. The X-ray diffraction (XRD) and Fourier Transforms Infrared (FTIR) confirmed the presence of a V-type crystalline structure and less crystallinity in RD43 rice flour, which resulted in a significant reduction of the water absorption index (WAI), swelling power (SP), water solubility index (WSI), gelatinization temperature, and pasting properties. Comparing with Hom Mali rice flour, RD43 rice flour had greater ability to disrupt cholesterol micellization and bind bile acid. Furthermore, it had lower starch digestibility, with a lower percentage of rapidly digestible starch (RDS) and higher percentage of undigestible starch than Hom Mali rice flour. Moreover, steamed muffins based on RD43 rice flour had lower starch digestibility than Hom Mali steamed muffins. The sensory analysis showed no significant differences between Hom Mali and RD43 steamed muffins. The findings suggest that RD43 rice flour could be an alternative ingredient for lowering the glycemic index of food products.
... Application of integrated cultivated throughout the world along with rice, production methods are recently considered as a means barley, maize, rye, sorghum, oats and millet. Nowadays, to reduce production costs, to efficiently use human wheat cultivars have been developed for different labor and other inputs and to protect the environment qualities in accordance with the development of genetic (often in conjunction with high numbers of tourists recombination [1]. Wheat is grown under irrigated as present in the area). ...
... (1) derived from Neyman technique [19]. (1) where n is the required sample size; N is the number of holdings in target population; Nh is the number of the population in the h stratification; Sh is the standard deviation in the h stratification, S2h is the variance of h stratification; d is the precision (x -X); z is the reliability coefficient (1.96 which represents the 95% reliability); D2 =d2/ z2. ...
... The mechanical energy was computed on the basis of total fuel consumption (L ha ) in different operations. 1 100% of total land in each farm was irrigated; Land in the selected farms was owned (100%). The input used in wheat production and their energy equivalents, output energy equivalent and energy ratio are illustrated in Table 2 and Table 3, respectively. ...
The aim of this study was to examine direct and indirect input energy in per hectare in whea t production. The research also sought to analyse the effect of farm size. For this purpose, the data were collected from 300 wheat farmers by questionnaire method. The results indicated that wheat production consumed a total of 38.36 GJ hā of which fertilizer energy consumption was 38.45% followed by diesel and machinery energy. 1 Output-input energy ratio and energy productivity were found to be 3.13 and 0.16 kg of wheat MJ̄ , 1 respectively. Large farms were more successful in energy use and energy ratio. It was concluded that energy use management at farm level could be improved to give more efficient and use of energy.
... Increasing amylose content by selective breeding can lead to disruption of the semi-crystalline structure of starch, leading to e.g. alteration of polymorphism, birefringence pattern and size/shape of starch granules (Cai, Zhao, Huang, Chen, & Wei, 2014;Van Hung, Maeda, Miskelly, Tsumori, & Morita, 2008). For example, compared to normal maize starch, high-amylose maize starches have aggregated and elongated granules with multiple birefringent regions. ...
... (Cai et al., 2014). Wheat starches with slightly raised amylose contents up to 36.9 % have similar granular shapes as normal wheat starches, but the surface of the high-amylose wheat starches are damaged and cracked (Van Hung et al., 2008). When the amylose content is elevated to > 67 %, high-amylose wheat starches have distorted granules Regina et al., 2015). ...
High-amylose wheat starch (HAWS) and flour (HAWF) have the potential to deliver food products with enhanced nutritional functionality, but structure/function relationships are not well understood. We report the structural bases for differences in water absorption and pasting properties for HAWS and HAWF (amylose contents 71-84%) compared with wild-type (WTWS/WTWF). With higher amylose content, the proportion of longer amylopectin chains with DP > 25 increased. Both the degree of branching and the branch lengths of amylose were lower for HAWS than WTWS. Compared with WTWF, HAWF contained less total starch, more protein, had lower peak viscosity by high-temperature RVA, lower dough development time and stability time and higher water absorption by Farinograph. Water absorption by HAWS was ∼1.5 times greater than for WTWS, suggesting loose packing of polymers within HAWS granules. Consistent with this, crystallinity and birefringence of starch granules were lower in HAWS.
... Wheat (Triticum aestivum L.) is among the oldest and most extensively grown of all crops (Hung et al., 2008). It is the main cereal cultivated throughout the world along with rice, barley, and maize. ...
... It is the main cereal cultivated throughout the world along with rice, barley, and maize. Wheat cultivar has been developed for different qualities in accordance with the development of genetic recombination (Hung et al., 2008). It is also grown under irrigated as well as rainfed conditions. ...
the total energy input (tEI) of irrigated wheat in Fars province, Iran, was estimated at 901 liter diesel oil equivalent per hectare (LDOE ha-1) (423 LDOE or 4819 Mcal, (47%) and 478.14 LDOE or 5454 Mcal, (53%) for wheat production and post production, respectively. the tEI for 1 ton wheat was estimated at 200 LDOE and for 1 ton of bread at 181 LDOE (wheat bread at 28% moisture). the direct use of fossil fuel oil in land preparation, planting, harvesting and transportation was estimated at 106 LDOE ha-1. the applications of fertilizer and pesticide contributed about 40% of the total energy bill in production while it was larger in baking the bread at 72.3 LDOE ton-1 or 75% of the energy costs of post production. At 4515 kg ha-1 average yield of irrigated wheat in Fars province, Iran, the energy output was estimated at 15848 Mcal for raw wheat, 13409.55 Mcal for bread and 2895 Mcal for straw. the energy balance for raw wheat production (field level) was estimated at 3.3. Post- production (baking bread) consumed a lot of energy. the estimated energy balance was 1.3. Measures on how to reduce the energy bill for wheat production and for post-production (baking bread) are discussed.
... The blue value and λ max of C-AS were 0.148 and 466.0 nm, while those of U-AS were 0.259 and 514.5 nm, respectively. The λ max value is influenced by amylose chain length, degree of polymerisation and amylopectin structure [68]. The amylose content is parallel to the blue value and the λ max value [69]. ...
Acorn (Quercus ithaburensis) is the fruit of the Quercus tree, with a rich chemical composition, used as a food for human consumption. Despite being rich in starch, more than half of the production of acorns (Quercus ithaburensis) is not utilised. This study aims to produce and characterise starch from acorn seeds using conventional and ultrasound-assisted methods. For this purpose, the starch production conditions of both methods were obtained from 2FI models using the desirability function approach and optimised using response surface methodology. In the classical method, the optimum extraction time, extraction temperature, and sample/solvent ratio were 3 h, 45 °C, and 1:3. In contrast, in the ultrasound-assisted method, the optimum extraction time, ultrasound frequency, and sample/solvent ratio were 30 min, 45 W and 1:2. The ultrasound-assisted method changed the functional properties of the starch. The amylose contents of starches produced by conventional and ultrasonic methods were 31.12 and 34.26, and the minimum gel formation rates were 18% and 14%, respectively. As a result of thermogravimetric analysis, 98.42% of conventional starch and 87.19% of ultrasonic starch was lost. IR-spectra also showed a similar pattern in both modifications, with the band's intensity at 1076 cm⁻¹ decreasing in the ultrasonically assisted method. Predicted glycemic index of starches ranged from 78.95 to 79.41. This study characterised acorn starch produced by different methods and demonstrated the demonstrated its potential for use in foods.
... Similarly, through genetic backcrossing, the amylose content of six wheat cultivars (Diamondbird, Pelsart, Banks, Lang, SM1028, and SM1126) was increased to 28.0%-36.9%, which was significantly higher than that of normal wheat starch (25.6%) ( Van Hung et al., 2008). Furthermore, Targeting Induced Local Lesions in Genomes (TILLING) was used to identify new alleles of SBEIIa, and combined with conventional breeding, high-amylose non-transgenic wheat varieties with an amylose content of 47.0%-55.0% ...
Resistant starch type 3 (RS3), often found in cooked starchy food, has various health benefits due to its indigestible properties and physiological functions such as promoting the abundance of gut beneficial microbial flora and inhibiting the growth of intestinal pathogenic bacteria. However, it is challenging to develop starchy food with high RS3 content. This review aims to provide a detailed overview of current advancements to enhance RS3 content in starchy food and its effects of RS3 on gut microbiota. These approaches include breeding high‐amylose cereals through gene editing techniques, processing, enzyme treatments, storage, formation of RS3 nanoparticles, and the incorporation of bioactive compounds. The mechanisms, specific conditions, advantages, and disadvantages associated with each approach and the potential effects of RS3 prepared by different methods on gut microbiota are summarized. In conclusion, this review contains important information that aims to provide guidelines for developing an efficient RS3 preparation process and promote the consumption of RS3‐enriched starchy foods to improve overall health outcomes.
... Compared to RDS, SDS provides a gradual increase of postprandial blood glucose level and can maintain blood glucose at a much longer period (Lehmann and Robin, 2007). Resistant starch acts as a fermentation substrate for beneficial microbes and possesses high concentration of amylose leading to its slow and resistant digestion nature (Hung et al., 2008). Banana starch comprises amylose content higher than those of corn, potato and wheat starch and BS is also known for its resistance to acid hydrolysis (Acevedo-Guevara et al., 2018). ...
Banana (Musa spp.), an evergreen perennial crop belonging to the Musaceae family, is one of the world's most important tropical and subtropical fruits. It is characterized by a wide variation in production, composition, and usefulness due largely to the cultivar, planting method, climate, as well as the availability of nutrients. Bananas are a rich source of essential minerals such as potassium, magnesium, and phosphorus, vitamins such as vitamins A, B6, B12, and C, and phytochemicals such as phenolic acids, flavonoids, tetrapenoids and catecholamines. The Cavendish group including cultivars like Grand Nain, Williams, Chinese, and Valery, is preferred over other cultivars due to a high yield potential and marketability both in the domestic and international markets. However, incomplete identification of cultivars used in producing flour, developing innovative products as well as postharvest losses, are key issues hindering the expansion of banana production. Identification of suitable cultivars and determining the applicable maturity stage of unripe banana is thus crucial for various food and industrial applications. This review therefore provides information on the taxonomy of bananas, their diverse cultivars, and elaborates on the composition of unripe banana flour required in various food applications.
... Pasting properties of starch sample suspensions (7%, w/v) were tested using a rapid visco analyzer (RVA, Newport Scientific, Sydney, Australia) based on the procedure described by a previous study [18] with moderate modification. The starch dispersions were subjected to the heating profile as follows: the temperature holding at 50 • C for 1 min, followed by heating from 50 • C to 95 • C and holding for 5 min, and, lastly, cooling to 50 • C with a holding time of 2 min. ...
Starch nanoparticles (SNPs) have unique attributes that make them suitable for specific applications. In this study, we assessed the optimum conditions for the fabrication of SNPs from the rice starches of low-(TCSG2) and medium-amylose rice lines (TK11) using pullulanase debranching combined with annealing treatment and evaluated their physicochemical and digestion properties. The highest crystalline SNP percent recoveries of 15.1 and 11.7% were obtained from TK11 and TCSG2, respectively, under the following debranching conditions: 540-630 NPUN/g, pH 5.0, 60 °C, and 12 h. The percent recovery of the crystalline SNPs by the combined modification of the de-branching and the annealing treatment with an extended annealing incubation prepared from TK11 and TCSG2 was significantly increased to 25.7 and 23.8%, respectively. The modified starches from TK11 had better percent recovery of the crystalline SNPs than those from TCSG2. They exhibited a higher weight-average molecular weight (Mw) and a broader/bimodal molecular weight distribution with a higher polydispersity (PDI) (Mw = 92.76-92.69 kDa; PDI = 4.4) than those from TCSG2 (Mw = 7.13-7.15 kDa; PDI = 1.7). Compared to the native counterparts, the color analyses showed that the modified starches from TK11 and TCSG2 exhibited decreased brightness (L*)/whiteness index (WI) values with marked color difference values (∆E) ranging between 6.32 and 9.39 and 10.67 and 11.32, respectively, presumably due to the protein corona formed on the surface of SNPs which induced the browning reaction during the treatments. The pasting properties revealed that the modified starches displayed restricted swelling power with extremely low pasting viscosities, reflecting that they were highly thermally stable. The modified starches, especially those treated with an extended annealing incubation, exhibited marked decreases in the rate and extent of digestion and estimated glycemic index due to the honeycomb-like agglomerates comprising an assembly of densely packed SNPs. The results could provide helpful information for the preparation and characterization of the crystalline SNPs for potential applications such as emulsion stabilizers for Pickering emulsion and health-promoting ingredients.
... Amylose (AM) contents ranged from 24.24% to 30.22%; amylopectin (AP) content varied from 42.03% to 89.80%; and relative crystallinity (RC), from 10.60% to 36.30% (Table 4). Wheat starch has amylose and amylopectin ratios ranging from 25%-28% to 72%-75%, respectively, and differences in the proportions between the polymer chains will influence the characteristics of starch, e.g., gelatinization (Hung, 2008). ...
Brazilian Cerrado wheat has emerged as an alternative to expand a new agricultural frontier in tropical areas. In this study, technological quality of 34 samples grown in five locations situated in the Cerrado Mineiro was evaluated in terms of their grain, flour and starch properties. Damaged starch was positively (p<0.05) correlated with Single Kernel Characterization System parameters (r=0.578) and pasting properties (r=0.761); and negatively (p<0.05) correlated with enthalpy (r=‐0.400) and relative crystallinity (r=‐0.379). The irrigation system strongly influenced the starch characteristics, rheological and pasting properties. Piumhi location showed the highest mean of resistant starch (0.80 g/100 g), bringing an interesting prebiotic appeal to these samples. Gluten index (mean=90.6) and damaged starch (mean=5.0%) values showed that genotypes present suitable standards for bakery products. This pioneering study highlights promising agronomic materials for cultivation in the Brazilian Cerrado region, which has great potential to produce tropical wheat.
... High-amylose wheat starch has asymmetrical, deformed, and crescentshaped granules with A-type crystallinity, while some high-amylose (28-36.9%) starches show C-type (similar to A-type crystals with unclear peaks at 5.2 and 4.8 2θ degree) (Hung et al., 2008). The highamylose content was observed on the periphery of granules compared to the center (core) and also linked with amylopectin (Jane, 2006). ...
Starch exists naturally as insoluble semi-crystalline granules assembled by amylose and amylopectin. Acknowledging the pioneers, we have reviewed the major accomplishments in the area of starch structure from the early 18th century and further established the relation of starch structure to nutritional functionality. Although a huge array of work is reported in the area, the review identified that some features of starch are still not fully understood and needs further elucidation. With the rise of diet-related diseases, it has never been more important to understand starch structure and use that knowledge to improve the nutritional value of the world's principal energy source.
... According to the use of starch for a variety of purposes, therefore, the starch plays an important role both in the food and non-food industry. Starch is a semi-crystalline polysaccharide that can be found in various vegetable kingdom sources, such as cereal grains (corn, wheat, rice) [18,19], tubers crop [20], stems [21,22], and legume [23,24]. The starch is a natural polymer containing different structure of glucose such as amylose (␣-1,4-glycosidic bond) and amylopectin (␣-1,6glycosidic bond) [25]. ...
This work aims to study the synthesis of flowers shaped silver nanoparticles (AgFLs) with green method by using corn starch (Co-S), cassava starch (Ca-S) and sago starch (Sa-S). The starch acts as a reducing agent in synthesis of silver nanoparticles and contains glucose by reducing silver ions from silver nitrate as silver nanoparticles. The silver nanoparticles were characterized by using Transmission electron microscopy (TEM), X-ray diffraction (XRD), UV–vis spectrophotometer, Fourier transform infrared (FTIR), Thermogravimetric (TGA) and Particle size analyzer. TEM images show the shape of synthesized silver nanoparticles as flowers-like and particle size distribution of synthesis of silver nanoparticles from corn starch, cassava starch and sago starch in the range of 47.8 nm, 107.5 nm and 118.9 nm respectively. The X-ray diffraction patterns indicated that silver nanoparticles had face-centred cubic (fcc) structure. The UV–vis spectroscopy shows the maximum absorption of silver nanoparticles at 420–430 nm. Therefore, synthesized silver nanoparticles with different starch were of flower-shape. Moreover, the size of flower- shape silver nanoparticles from by corn starch was smaller particle distribution than that of cassava starch and sago starch.
... Iodine binding by molecularly dispersed starch is typically used to estimate the nominal percentage of amylose in a starch sample. Higher BV indicates higher content of amylose (Hung, Maeda, Di, Tsumori, & Morita, 2008). It can be observed that as compared with native starch, gelatinization would increase the BV of starch. ...
As an emerging processing method, 3D printing attracts more attention on food manufacturing. The characteristics of 3D printed samples made from potato, wheat, and corn starch were investigated in this study. Morphology, color, iodine absorption spectra, rapid visco analyzer, texture analysis, Fourier transform infrared spectroscopy and scanning electron microscopy were used to evaluate the quality of products. The results indicated that all starch gels could obtain a complete 3D printing model. The dimension of 3D printed sample created by wheat starch was closest to the CAD designed model. Wheat starch gel displayed the lowest viscosity and better extrudability as well as better storage properties. Besides, the microstructure of 3D printed samples processed by wheat starch presented more regular network structure than potato and corn starch. The study provides a new theory for the application of 3D printing in food production and technical support for actual production.
Practical applications
3D printing also referred to as additive manufacturing, offers a wide range of new processing possibilities to the food industry. It potentially allows rapid manufacturing of complex objects, which are unhindered by design complexity, thus providing substantial liberty to create new and untested geometric shapes. In terms of food manufacturing, the potential that 3D food printing technologies can bring may revolutionize certain aspects of food manufacturing, providing the convenience of low‐cost customized fabrication and even tailored nutrition control. Be an emerging food processing method, it is important to develop more compatible materials. Starch is a polymeric carbohydrate composed of a large number of glucose units connected by glyosidic bonds. It is also the most abundant source of carbohydrate in human diet. Using starch as the 3D food printing material can be a good choice with good mechanical behaviors and lower cost.
... This could be attributed to the formation of differently sized crystallites during water equilibration. Hung, Maeda, Di, Tsumori, and Morita (2008) also reported that two melting peaks occurred during the gelatinization of Banks high-amylose wheat star- ches with Tp values of 62.60 and 101.3 °C. However, DBSP3.0(20) ex- hibited a relatively narrow melting peak with a melting temperature range (Tc-To) of 20.49 °C and a low melting enthalpy change of 2.86 J/ g. ...
Debranched starch (DBS) has attracted immense interest from the food, pharmaceutical, and cosmetic industries as a versatile ingredient. Herein, we firstly developed a simple fractionation method using an edible alcohol solution to separate DBS of different degrees of polymerization (DP). These DBSs were separated from debranched waxy corn starch on the basis of their differential solubility in aqueous/ethanol solutions of different volumetric ratios (1:1.5 and 1:3). Four DBS products were obtained with DP values of 23.53, 20.04, 9.14, and 6.75. The DBS (DP 23.53) exhibited higher iodine staining index values compared to DBSs of lower DPs. The thermograms of DBSs (DP 9.14 and DP 6.75) displayed no apparent peak, indicating their amorphous nature. Compared to freeze-drying, oven-dried DBS (DP 23.53) exhibited a higher relative crystallinity (72.0%). Therefore, the ethanol precipitation method developed here serves as a simple, scalable, and green approach for preparing DBS fractions of different molecular weights.
... The specific contribution of HAW starch to dough rheology at constant protein quality and content warrants further investigation. HAW starch granules possess a more irregular shape and rougher surface compared to CW starch granules (Hung et al., 2008;Regina et al., 2006;Yamamori et al., 2000). The difference in shape and surface characteristics of HAW starch granules would likely increase the starch-starch and starch-protein interactions, leading to changes in dough behaviour. ...
High amylose wheat (HAW) starch has been the focus of a number of nutritional studies, but there is limited information around its effect on the mechanical properties of wheat flour dough. This study investigated the size, shape and packing volume of HAW starch and their effect on the microstructure and rheology of dough. Four flour blends were formulated by adding vital wheat gluten and either HAW or commercial wheat starch to HAW flour to achieve a constant 14% protein content, but varied amounts of HAW starch. A large number of small and irregularly shaped HAW starch granules resulted in a high packing volume per gram of starch. Confocal laser scanning microscopy of optimally mixed doughs correlated the degree of starch granule aggregation with the level of HAW starch in the bi-continuous dough network. Small deformation rheology demonstrated that increased quantities of HAW starch in the dough increased the elastic modulus G′ values. Uniaxial extension measurements highlighted a synergy between HAW starch and sources of gluten proteins resulting in increased strain hardening. The impact of HAW starch on dough rheology was attributed to its irregular shape and large number of small granules leading to greater granule-granule interactions.
... Both the blue value (BV) and the maximum absorption wavelength (k max ) of starch-amylose complexes were higher in the germinated-fermented sorghum flour than in control. Yu et al. (2012) reported that the BV and k max of rice starch and flour increased with the amylose content, whereas k max has been reportedly related to the average chain length of amylose and amylopectin (Huang et al. 2008). ...
The combined effects of grain germination and of subsequent fermentation on the physicochemical properties of sorghum flour were investigated by studying the structural changes occurring in the starch and protein fractions and by assessing their effects on physical properties of the resulting materials most relevant to end use. The sequential treatments were more effective than either individual treatment in the modification of starch-related properties, whereas modification of the protein components only occurs in the fermentation step, almost regardless of a previous germination step. The resulting profile of physicochemical traits offers several hints as for the suitability of flour from treated sorghum as an ingredient for various types of gluten-free food products, and provides a basis for expanding the use of processed sorghum in applications other than traditional African foods.
... Both the blue value (BV) and the maximum absorption wavelength (k max ) of starch-amylose complexes were higher in the germinated-fermented sorghum flour than in control. Yu et al. (2012) reported that the BV and k max of rice starch and flour increased with the amylose content, whereas k max has been reportedly related to the average chain length of amylose and amylopectin (Huang et al. 2008). ...
This study aimed to evaluate the effect of sorghum and sweet potato on the bioavailability of iron, gene expression of proteins involved in iron metabolism and the plasma antioxidant capacity in animals fed with whole sorghum grains processed by dry heat or extrusion, combined or not with sweet potato flour with high content of carotenoids. Five experimental groups were tested (n=7): dry heat sorghum flour (DS); extruded sorghum flour (ES); whole sorghum flour + sweet potato flour (DS + SP); extruded sorghum flour + sweet potato flour (ES + SP) and positive control (FS). The evaluations included: hemoglobin gain, hemoglobin regeneration efficiency, gene expression of divalente metal transporter 1 (DMT-1), duodenal citochroma B (DcytB), ferroportin, hephaestin, transferrin and ferritin and total plasma antioxidant capacity (TAC). The ES+ SP group showed higher (p<0.05) expression of DcytB, ferroportin and hephaestin when compared to the control group. The DS group showed high (p<0.05) expression of DMT-1 and the ES showed high mRNA expression of transferrin and ferritin. The changes in the sorghum physicochemical properties from extrusion process reduced the iron and phytate content, and increased the gene expression of proteins involved in iron metabolism, improving iron bioavailability. The combination of sweet potato and sorghum flour (dry or extruded) improved the iron capture and total antioxidant capacity, probably due to the presence of β-carotene and antioxidant compounds.
... However, the difference due to rice type was much larger as indicated by the F value (Supplementary Table 1). λ max of starch is reported to relate to the degree of polymerization and average chain length of amylose and amylopectin (Hung, Maeda, Miskelly, Tsumori, & Morita, 2008). Thus, the higher blue value and λ max of NTP treated long grain rice in the present study might be due to an increase in branching of chains in molecules of amylose and amylopectin. ...
... In contrast, the maximum absorption wavelength of the high-amylose maize starch was significantly lower than that of the normal maize starch. This result agreed with the high-amylose wheat starches isolated from Australian wheat cultivars as previously reported by Hung, Maeda, Miskelly, Tsumori, and Morita (2008). ...
High-amylose maize starch is of interest because of its health benefits and industrial uses. Hybrid maize is widely grown for the practical and economical value of heterosis. However, starch structure of high-amylose hybrid maize has seldom been reported compared with that of high-amylose inbred maize. In this study, structure of starches from high-amylose maize inbred lines and their hybrids was investigated and compared. Starch granule became smaller in size and more spherical, oval or elongated in shape with increasing amylose content. Hybrid maize starch had lower amylose content and long branch-chain of amylopectin and higher short branch-chain and branching degree of amylopectin than inbred maize starch. Inbred maize starch had B-type crystalline structure with low relative crystallinity, but hybrid maize starch had CB-type crystalline structure and high relative crystallinity. Hybrid maize starch had lower degree of order at a short-range scale on the edge of starch granule than inbred maize starch. Hybrid maize starch had higher double helix content and lower amorphous starch than inbred maize starch. Hybrid maize starch had higher peak intensity and longer Bragg spacing of lamellar structure than inbred maize starch. Hybrid maize starch had lower gelatinization temperature and higher gelatinization enthalpy and swelling power than inbred maize starch. The different structural properties of starches had significant correlation.
... It is a main cereal cultivated throughout the world along with rice, barley, maize, rye, sorghum, oats and millet. Nowadays, wheat cultivars have been developed for different qualities in accordance with the development of genetic recombination (Hung et al., 2008).Wheat is grown under irrigated as well as rain-fed conditions worldwide. Under rain-fed conditions the developing grains are frequently exposed to mild to severe stress at different stages of grain development (Singh et al., 2008). ...
The aim of this study was investigated the cost of wheat production in Iran and the effect of combine availability on harvesting cost. Information of combine number and cost of wheat production in each province, for this period (2000 – 2006), attained from Ministry of Jihad-e-Agriculture of Iran statistics. Data from variable costs such as land preparing, planting, cultivating, harvesting and land price in each province in each year was entered into computer. Comparisons between means of producing cost, specially harvesting cost, were carried out with use of SPSS15. To compare the mean of costs in each province Duncan test was used. The result showed that the cost of wheat harvesting in provinces has decreased with increasing the number of combine harvester in provinces. Therefore for decreasing the harvesting cost in Iran provinces it is necessary to distribute more combine harvester in provinces.
... If It has been reported that an increase in amylose content would be expected to be accompanied by decreasing crystallinity, decreasing melting enthalpy and decreasing values of melting temperature of the amylopectin crystallites in native wheat starch granules with amylose content less than 50% (Koroteeva et al., 2007a, b;Kozlov et al., 2007b). In agreement with results by Hung et al. (2008), our results did not confirm these trends. Insignificant differences in total crystallinity and the lack of correlation between T m and any of the studied characteristics within the set of varieties from VAWCRC program indicates that there may be several underlying factors affecting lamellar structure that may mask general trends that occur over a wider range of amylose content. ...
... ) for the second endotherm has been reported for high amylose Australian wheat cultivars (Hung et al., 2008). ...
Starches from nine Indian wheat lines were evaluated to study the relationships between physicochemical and rheological properties. Large granules (>15 μm) were present in the highest proportion followed by medium (5–15 μm) and small granules (G′ peak (576 Pa) and G′ final (432 Pa). Amylose content showed positive relationships with retrogradation, gel firmness, gumminess and adhesiveness while negative with springiness. Cooked starch pastes with the highest amylose content (37.2%) had higher ΔH ret (0.88 J g−1), G′ ret (361 Pa), adhesiveness (1.48 Ns), firmness (0.45 N) gumminess (0.22 N) and the lowest springiness (0.88). Amylose–lipid complex (AML) dissociation showed negative relations with swelling power, G′ peak, G′ breakdown and breakdown viscosity (r = −0.779, −0.66, −0.771 & −0.775, respectively, P 0.05) while positive relationship with pasting temperature (r = 0.775, P 0.05).
... The results suggested that all of the starches with high blue values contained the high concentration of amylose. Huang et al. (2008) determined the amylose content and blue value of six high-amylose wheat cultivars. It was concluded that the WSs containing generally higher amylose contents displayed the higher blue values. ...
In this study, the ghost structures of potato starch granule gelatinization in the presence and absence of Mesona Blumes gum ( MBG ) at different temperatures and time points were studied. Our results indicated that ghost structures could form merely after the amylose was completely leached from granules. In addition, MBG could prevent amylose from leaching outside the granules, and thus extend ghost structure existence in aqueous solution. Furthermore, the interactions among eight kinds of starches and MBG were assessed by B rabender parameters. It was concluded that rice, wheat, pea and corn starches could be significantly influenced by MBG ( P < 0.05), then followed by mung bean and sweet potato starch, whereas the effects of tapioca and potato starch could be insignificant ( P > 0.05). Textural measurement illustrated that MBG /rice starch gel was the hardest among all samples in this study. Rheological properties of rice starch and various hydrocolloids were evaluated at 25 C by frequency sweep from 1 to 10 Hz with a constant strain 1%. It was shown that rice starch and MBG could also form the strongest gel.
Practical Applications
To understand the interaction between MBG and different starches from various sources, ghost structures, B rabender curves, and textural and rheological properties were investigated in this paper. Ghost structure indicated that gels between MBG and starch might be constituted by collapsed starch granule, MBG and swollen amylose. B rabender curves showed that MBG could affect rice starch gelatinization significantly ( P < 0.05). Moreover, the results of textural studies also demonstrated that MBG /rice starch gels formed the hardest gel. In addition, the results obtained from rheological properties between various hydrocolloids and rice starch suggested that the strongest MBG /rice starch gel occurred. Therefore, gels formed by MBG and rice starch might be potentially used as a novel filler or thickener in food industry.
... It is a main cereal cultivated throughout the world along with rice, barley, maize, rye, sorghum, oats and millet. Nowadays, wheat cultivars have been developed for different qualities in accordance with the development of genetic recombination (Hung et al., 2008). Wheat is grown under irrigated as well as rain-fed conditions worldwide. ...
Energy use efficiency in the wheat production as one of the key indicators for developing more sustainable agricultural, was studied by analysis of energy flow in this crop in Kermanshah province of Iran in 2012. Data was collected using questionnaires and face to face interviews with 70 farmers. Total inputs and outputs of wheat systems were calculated and converted to their energy equivalent. Results indicated that total energy input and output in wheat production were 16762.8 and 143070.4 MJ/ha, respectively. The highest share of input energy was recorded for chemical fertilizer (31.5%), diesel fuel (30.04%) and water for irrigation (16.7%). The results also showed that energy ratio, energy productivity and net energy were 8.52, 0.25, and 126307.6 MJ/ha-1 respectively. In this study also the Data Envelopment Analysis (DEA) method is used to estimate the energy efficiencies of wheat producers the following results were obtained: 15.7% and 57.1% of farmers were found to be technically and pure technically efficient, respectively. The average values of technical, pure technical and scale efficiency scores of farmers were found to be 0.83, 0.97 and 0.86, respectively. Also, energy saving target ratio for wheat production was calculated as 2.2 %, indicating that by following the recommendations resulted from this study, about 371.99 MJ ha-1 of total input energy could be saved while holding the constant level of wheat yield.
... Depending on amylose content, corn starch is generally classified as waxy (essentially devoid of amylose), normal (20-35% amylose), or high-amylose (>40% amylose) types (Tester et al., 2004;Kuakpetoon and Wang, 2008), though this classification often varies according to the botanical origin (e.g., wheat, rice). For example, wheat starch is subdivided into waxy (0-3% amylose), partial waxy (16-23% amylose), normal (25-28% amylose), and high-amylose (30-37% amylose) categories (Graybosch, 1998;Geera et al., 2006;Van Hung et al., 2008). ...
Ultra high pressure (UHP) processing is an attractive non-thermal technique for food treatment and preservation at room temperature, with the potential to achieve interesting functional effects. The majority of UHP process applications in food systems have focused on shelf-life extension associated with non-thermal sterilization and a reduction or increase in enzymatic activity. Only a few studies have investigated modifications of structural characteristics and/or protein functionalities. Despite the rapid expansion of UHP applications in food systems, limited information is available on the effects of UHP on the structural and physicochemical properties of starch and/or its chemical derivatives included in most processed foods as major ingredients or minor additives. Starch and its chemical derivatives are responsible for textural and physical properties of food systems, impacting their end-use quality and/or shelf-life. This article reviews UHP processes for native (unmodified) starch granules and their effects on the physicochemical properties of UHP-treated starch. Furthermore, functional roles of UHP in acid-hydrolysis, hydroxypropylation, acetylation, and cross-linking reactions of starch granules, as well as the physicochemical properties of UHP-assisted starch chemical derivatives, are discussed.
The demand for agricultural goods is currently higher than it has ever been before due to the expansion of the world population. This has resulted in the conversion of grassland into agricultural areas, the development ofhigh-energy-intensive agriculture production systems, and the use of additional chemical and organic inputs inagricultural production systems. The output of greenhouse gases (GHGs) has also increased in the same way.Carbon dioxide (CO2), Nitrous Oxide (N2O), and Methane (CH4) is the most significant greenhouse gases (GHGS)that are producing a variety of disastrous consequences due to climate change. Despite the fact that CH4 and N2Oare released in smaller amounts than CO2, they have a larger Global Warming Potential than CO2. This analysisbegins with an examination of the variables that contribute to greenhouse gas emissions, which covers bothinorganic factors (such as nitrogen, phosphorus, and potassium fertilizers) and organic factors (Animal manure,composted manure, bio-solids, crop species). This study underlines the need for more research into the intricateinteractions of physical, chemical, and biological elements in the near future. Field crops other than cereals, suchas legumes, oilseeds, vegetables, and fruits, account for a significant amount of greenhouse gas (GHG) emissions.Precision agriculture may be a viable option for increasing agricultural efficiency. Optimal management prac-tices should be implemented in farm and field settings through methodical, site-specific approaches.
A thorough understanding of structural changes during gelatinization is extremely important for precise control of starch functional properties for food processing and human nutrition. Here we select five starches with different amylose content between 1.06% and 63.08% to reveal the relationship between the structural changes and amylose content during starch gelatinization by Raman spectroscopy and X‐ray diffraction (XRD) in conjunction with a protocol using the rapid viscosity analyzer (RVA) to generate material for analysis. The results show that the high‐amylose starch had stronger resistance to gelatinization, and its long‐range order structure is more stable which is consistent with the conclusion that certain residual crystallinity remained after gelatinization. Meanwhile, the destruction of short‐range order structure was not significant compared with that in low‐amylose starch when the temperature reached the pasting temperature. These phenomena are related to the fact that the high‐content amylose promotes the formation of the amylose‐lipid complex during the gelatinization by differential scanning calorimeter (DSC). The presence of the amylose‐lipid complex can restrain the swelling of starch granules and maintain their molecular structure during heating. This article is protected by copyright. All rights reserved
Cereal grains comprise part of the traditional eating habits of different cultures. Wheat alone accounts for 20% of the daily protein and the food calories of 4.5 billion people worldwide. Wheat quality, in the wider sense, involves carbohydrate, protein, and micronutrient composition, grain processing, and food safety. Wheat seed components, both those that contribute to the energy required from the human body and those with a positive activity, such as phenolic compounds with antioxidant capacity, have to be considered in an introduction to wheat and breadmaking. This chapter will address the potential for including wheat in the human diet as a means of promoting health. Processing of wheat represents another significant aspect of the food production chain, because of the great variation in the composition of the different anatomic parts of the wheat kernel and their functionality. This chapter provides an introduction to wheat kernel composition, breadmaking steps, and processes. It will also introduce to the reader the content and the aims to be achieved by this book and briefly highlight the topics that are going to be covered.
The low temperature in spring is a meteorological problem in wheat production because it leads to yield reduction and alteration of wheat quality. In this study, an artificial low-temperature treatment (LTT) at the stem elongation stage was implemented to investigate the starch granule development and physical and chemical properties of wheat starch. Results showed that the agronomic traits of spike, such as spike length, spikelet number per spike, and grain number per spikelet, decreased after LTT. LTT promoted the development of starch granules in developing grains at 15 days post-anthesis, resulting in increased B-type granules and reduced C-type granules with an irregular shape in mature grains. The swelling power of the starch granules was reduced, but their solubility was enhanced by LTT. The proportion of the amorphous structure within the granules increased, but the crystalline component decreased after LTT, leading to a significant reduction in the relative degree of crystallinity and double- and single-helix structures. Three types of hydrolysis showed that starch in LTT was easy to hydrolyze, resulting in a high degree of hydrolysis. The findings suggest that low temperature at the stem elongation stage can not only reduce the yield parameters of spike but also alter starch accumulation, thereby affecting the processability and structure characteristics of starch in wheat grains.
Starches from extraordinarily soft wheat (Ex-SW), medium-hard wheat (MHW) and hard wheat (HW) varieties were evaluated for various properties and their relationship with each other was established. Varieties showed wide variation in grain hardness index (GHI) that varied between 17 and 95. Starches were evaluated for physicochemical properties, granule size distribution, starch morphology, pasting and thermal properties. Starches from MHW showed the presence of the largest proportion of A-type granules and the smallest proportions of B-type and C-type granules whereas Ex-SW showed the greatest proportion of C-type granules. Starches from HW and MHW varieties showed lower swelling power (SP) and higher amylose content (AC) than that from Ex-SW varieties. Starches from HW varieties had greater crystallinity than starches from Ex-SW. Transition temperatures of starch gelatinization decreased with decrease in GHI.
Lots of bananas were wasted before commercialization. It is necessary to search potential industrial applications of banana. In the present study, starches from seven banana cultivars (labeled as A-G) were isolated and then characterized. These starches presented different and irregular shapes, such as sphere, long spheroid and polygonal granules. The distribution of size and analyses of average molecular weight showed more small granules in samples B, D, F and G than other samples. The amylose content varied from 22.59% to 38.40%. The crystal types of these starches were a mixture of B-type and C-type, and the relative crystallinity varied greatly. The differential scanning calorimetry (DSC) results showed that the onset temperature of gelatinization increased as follows: A < B < E < C ≈ D < F. The maximum viscosity of banana starch decreased as follows: G > C > D > F > E = B > A. The in vitro digestibility test showed that the content of resistant starch was very high in banana starches. These results would be useful to the application of those starches in food and nonfood industries.
This present study was aimed to evaluate proximate composition, antioxidant activity, amino and phenolic acids, protein profile and pasting characteristics of pigmented rice (PR) and non pigmented rice (NPR) landraces grown in Himalayan region. Higher antioxidant activity, total phenolic content, fat and protein content were observed for PR as compared to NPR. Histidine, iso-leucine, lysine, methionine, phenyl-alanine, valine and threonine were significantly higher for PR. Paste viscosities were higher for NPR (except IC568266) as compared to PR. IC568266 was observed to be waxy landrace. Higher free (gallic acid, catechin, caffeic acid, vanillic acid, sinapic acid and luteolin) and bound phenolics (ferulic acid, p-coumaric acid and quercetin) were observed in PR as compared to NPR. Majority of PR landraces showed higher accumulation of prolamines with low molecular weight polypeptides of 18, 20 and 29 kDa as compared to NPR. PR showed the higher essential amino acids, phenolic acids (p-coumaric acid, ferulic acid and quercetin) and antioxidant activity with improved nutritional value and showed potential for developing nutraceutical and functional foods.
Background and objectives
Physicochemical, amino acids, phenolic acids, protein profiling and rheological characteristics of milled rice (MR) from different traditional (IC362109, IC568259 and IC548363) and improved paddy varieties (PR113, PR127 and PB1121) and its utilization for making gluten free chapati using pearl millet (PM) flour were investigated.
Findings
Higher L*, antioxidant activity, protein content, phosphorus (P), potassium (K), foaming and water absorption capacity were observed for MR from improved paddy varieties (IPV) as compared to traditional paddy varieties (TPV). The higher accumulations of gallic acid, catechin, ferulic acid, p‐coumaric acid and protocatechuic acid were found in MR from IPV. Histidine, iso‐leucine, lysine, methionine, phe‐alanine, valine and threonine were higher for MR from IPV as compared to TPV. Higher accumulation of glutelins (33 and 31 kDa; 22 and 20 kDa) and prolamins (18 kDa, 16 kDa and 15 kDa) were observed in MR from IPV. MR from IPV showed better rheological properties as compared to TPV. Rheological parameters (Gʹ, Gʹʹ and tan δ) of dough from PM flour were increased with increasing incorporation of rice flour. The chapati made from PB1121 (IPV) showed higher consumers’ acceptability and increasing the health benefits. MR from IPV showed high nutritive value and processing quality in food industries.
Conclusions
from IPV showed better nutritional and rheological properties and more useful for utilization in making gluten free chapati (highly nutritious and acceptable). Chapati made from 20% MR from PB1121 (IPV) was better in appearance, taste, texture and palatability.
Significance and novelty
The research appears to have greater potential to highlight the gluten free aspect and also health and nutritional benefits of the IPV for food products for the future and application in additional composite style products.
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Starch constitutes the major carbohydrate in the endosperm of wheat grains and serves as a multifunctional ingredient for the food or nonfood industries. The functional properties of starch are important for their use in food products and industrial applications, especially the pasting properties and gelatinization and retrogradation characteristics. These properties in respect to wheat starch are characterized in this chapter. Furthermore, the chapter discusses the methods of wheat starch isolation, its molecular structure, and the resulting functional properties. The influence of its components, protein, lipids, and nonstarch polysaccharides, present both on the surface and inside wheat starch granule, on shaping its properties has been characterized. The important role of starch interactions with bioactive compounds on the formation of its functional properties has been indicated as one of the most intensively developing research area concerning starch. The positive impact of resistant starch (RS) on the improvement of human health is also stressed.
Although the processing and eating qualities of noodles are largely related to the quality and quantity of wheat protein (gluten), the importance of starch, a major ingredient of wheat flour, is often overlooked. Recent developments on the multilevel structural model of starch have brought new insights into the role of starch for better processing and noodle eating qualities. With critical analysis and discussion, this review outlines the comprehensive relationships between the multilevel (molecular, crystalline, and granular) starch structure, noodle eating qualities, and related physicochemical properties. Further, the major and minor structural features of wheat starch and their contributions toward noodle quality are summarized and presented as a schematic diagram, which shows the effects of starch structure on cooked noodles. These features provide new insights for the scientific community, as well as industry, into the role of starch, along with gluten, on the quality of noodles.
Starch is the main component of wheat having a number of food and industrial applications. Thousands of cultivars/varieties of different wheat types and species differing in starch functionality (thermal, retrogradation, pasting and nutritional properties) are grown throughout the world. These properties are related to starch composition, morphology and structure, which vary with genetics, agronomic and environmental conditions. Starches from soft wheat contain high amounts of surface lipids and proteins and exhibit lower paste viscosity, whereas that from hard cultivars contain high proportion of small granules and amylose content but lower gelatinization temperature and enthalpy. Waxy starches exhibit higher-percentage crystallinity, gelatinization temperatures, swelling power, paste viscosities and digestibility, but lower-setback viscosity, rate of retrogradation and levels of starch lipids and proteins than normal and high-amylose starches. Starches with high levels of lipids are less susceptible towards gelatinization, swelling and retrogradation and are good source of resistant starch, while that with high proportion of long amylopectin chains are more crystalline, gelatinize at high temperatures, increase paste viscosity, retrograde to a greater extent and decrease starch digestibility (high resistant and slowly digestible starch and low rapidly digestible starch).
A high-amylose starch was prepared from ginkgo by hydrolysis using isoamylase and its structures (morphology and crystallinity) and physicochemical properties (swelling factor, water solubility and gelatinization) were determined. The experiments used response surface methodology to determine the optimum parameters for enzymatic hydrolysis: pH 5.0 at 52 °C for 170 min, using an enzyme dose greater than 100 IU/mL. The experimentally observed maximum yield of ginkgo amylose under these conditions was 74.74% and the blue value was 0.756. The high-amylose ginkgo starch showed an irregular surface and porous inner structure while the native starch granules were oval with a smooth surface. X-ray showed that the high-amylose starch displayed a V-type structure. Because of its high amylose content and different structural characteristics, high-amylose starch exhibited a higher gelatinization peak temperature (109.25 °C) and water solubility, and a lower crystallinity (19.13%), gelatinization enthalpy (63.83 J/g), and swelling power. The present study has indicated that high-amylose starch prepared using isoamylase has unique functional properties, which lays the foundation for the wider application of ginkgo starch.
The native and physically modified rice starches with varying amylose contents were subjected to investigate the in vitro digestibility and the in vivo glucose tolerance in mice. The amylose and resistant starch (RS) contents of five native rice starches ranged in 4.7-30.6% and 6.3-11.8%, respectively. The RS contents of rice starches increased to 18.5-23.9% after heat-moisture treatment (HMT) and to 19.5-26.9% after annealing treatment (ANN). The heat-moisture and annealing treatments significantly reduced glycemic index (GI) values of the rice starches. GI values of the native, heat-moisture treated and annealed rice starches ranged in 68.9-100, 61.2-88.9 and 21.2-43.9, respectively. There was no correlation between amylose contents and the RS contents or GI values, while a strong negative correlation between RS contents and GI values was found (R(2)=-0.747, P<0.01).
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The effects of a combination of acid and heat-moisture treatment on formation of resistant starch (RS) and characteristics of high-amylose, normal and waxy rice starches were investigated in this study. The degrees of polymerization of the rice starches treated with citric acid, lactic acid or acetic acid were significantly reduced as compared to the native starches. The RS contents of acid and heat-moisture treated rice starches were in a range of 30.1-39.0%, significantly higher than those of native rice starches (6.3-10.2%) and those of heat-moisture treated rice starches (18.5-23.9%). The acid and heat-moisture treatments reduced swelling power and viscosity, but increased solubility of the starches, while the crystalline structure did not change. Among the organic acids used, citric acid had the most impact on starch characteristics and RS formation, followed by lactic acid and acetic acid. The results are useful in production of RS for functional food application.
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Fusarium culmorum is a ubiquitous soil-borne fungus which is able to cause foot and root rot on different small-grain cereals, in particular wheat and barley. Wheat (Triticum aestivum L.) is among the oldest and most extensively grown of all crops. Systemic acquired resistance (SAR) is a pathogen-induced disease resistance response in plants that is characterized by broad spectrum disease control. SAR is an important component of the disease resistance repertoire of plants. The effect of the resistance inducer, methyl jasmonate (MeJA), was tested by seed-soaking to determine whether this resistance inducer controlled root rot of wheat caused by F. culmorum. MeJA is an inducing disease resistance in a number of dicotyledonous and monocotyledonous plant species. This research has been conducted to determine the effect of MeJA seed treatment on chlorophyll a, chlorophyll b, total protein, peroxidase (POD) enzyme, phenolic compounds and phenylalanine ammonia lyase (PAL) factors. MeJA, which is an important chemical inducer of SAR, can activate resistance to pathogen infection in commercial crops. Seeds treated with MeJA showed an elevation in the total chlorophyll, carotenoid and activity of defence-related enzymes, POD and PAL.
Debranching starch by pullulanase is considered to improve the RS content of starch which is widely used to produce the starch-based foods with high-health benefit impacts. In this study, the cassava and potato starches were debranched by pullulanase, followed by an autoclave treatment and storage at −18°C, 4°C, or 25°C to investigate their crystallinity and functional properties. After debranching, the potato starch contained significantly higher CL (35.4 glucose units) than did the cassava starch (32.4 glucose units). The debranched cassava and potato starches after retrogradation at the storage temperatures had a typical B-type crystalline structure although the native cassava and potato starches exhibited the different crystalline forms (A- and B-type, respectively). The RS contents of the debranched cassava and potato starches significantly improved with higher RS content of the debranched potato starch than that of the debranched cassava starch at the same storage condition. The storage temperature significantly affected the RS formation of the debranched starches with the highest RS content at storage temperature of −18°C (35 and 48% for the debranched cassava and potato starches, respectively). The debranched starches had significantly lower viscosities and paste clarities but higher solubilities than did the native starches. As a result, the debranched cassava and potato starches can be considered for use not only in functional foods with enhanced health benefits but also in pharmaceutical and cosmetic industries.
The objective of this study is to investigate formation of slowly digestible starch (SDS) and resistant starch (RS) and change in physicochemical properties of sweet potato and yam starches under a combination of acid and heat-moisture treatments using three mild organic acids including acetic acid, lactic acid and citric acid and heating temperature at 110 oC for 8h. The results show that the SDS and RS in sweet potato starch significantly increased from 6.6% and 14.7% in native starch to 8.7% – 13.2% and 37.5% – 42.1% in acid and heat-moisture treated starches, respectively. Likewise, the SDS and RS in yam starch increased from 4.7% and 21.6% in native starch to 10.0% – 11.3% and 39.0% – 46.4% in the treated starches, respectively. The RS content in the acid and heat-moisture treated starches also significantly higher than that of the heat-moisture treated starches without acid hydrolysis. Yam starch produced higher amount of RS under acid and heat-moisture treatment as compared to sweet potato starch at the same condition. Swelling power and viscosity of starches significantly reduced, whereas the solubility significantly increased after treatments. The citric acid had the most impact on RS formation and starch properties, followed by lactic acid and acetic acid. As a result, the combination of acid and heat-moisture treatment is a useful method to produce higher amount of resistant starch which can be applied for functional foods.
Nowadays, there are many breeding program to improve the quality of rice since the direct measurement (iodine colorimetric) is time consuming, complex and environmentally unfriendly. The objective of this study was to analyze the amylose content (AC) in several types of local rice and import rice in Malaysia. Next is to investigate suitable rice intake for diabetic patient. In this study, non-destructive method by using Near-Infrared Spectroscopy (NIRS) was used to measure the amylose content of single rice grain for milled rice and brown rice. The result showed that the AC for the brown rice was higher than basmati rice followed by local white rice. Therefore, the high amylose content is most suitable for the diabetic patient. Thus, NIRS was a convenient way to screen the quality of rice as well as increase the global competitive for farmers in agriculture field.
The susceptibility of wheat (Triticum aestivum L.) starches to hydrolysis by pancreatic α-amylase in vitro was investigated using a series of 35 starches with slightly enriched amylose content within a narrow range (36–43%), but widely differing functional properties. After 2 h of incubation with α-amylase, native starch granules were digested to different extents, but there were no differences between any of the starches once they were gelatinized. Cooling the starch for 72 h at 4 °C after cooking reduced the susceptibility of all of the starches to enzymic digestion by a similar extent, whereas addition of monopalmitin decreased the digestibility of the starches that contained amylose, but did not affect the digestibility of waxy starches that were also included in the study. Amylopectin chain length distribution of partly digested starch granules displayed increased proportion of short and medium chains and decreased proportion of long chains in comparison to native granules. Separated large (A) and small (B) starch granules from three of the starches differed significantly in their susceptibility to in-vitro digestion. A predictive model of the susceptibility of starch in the different forms was developed from the physico-chemical and functional properties of the starches.
The starches and flours from four different rice cultivars were evaluated for composition, crystallinity characteristics,
blue value, turbidity, swelling power, solubility, pasting properties, and textural and retrogradation properties. The amylose
content of starches and flours from different rice cultivars differed significantly. The results showed that the physicochemical
properties of rice starch and rice flour were correlated to amylose content. The crystallinity degree of rice starch and flour
depended on amylose content. The blue value, turbidity value, and gel hardness were positively correlated to amylose content;
however, the swelling power, solubility, and gel adhesiveness were negatively correlated to amylose content. Furthermore,
the pasting properties and gel textural and retrogradation properties of rice flours were related to the structure properties
of rice starch. And the characteristics of starch, protein, and lipid significantly influenced the turbidity, pasting properties,
and gel textural and retrogradation properties of rice flours.
KeywordsAmylose–Rice starch–Rice flour–Physicochemical properties–Rice
Small-angle X-ray scattering (SAXS) together with several complementary techniques, such as differential scanning calorimetry and X-ray diffraction, have been employed to investigate the structural features that give diverse functional properties to wheat starches (Triticum aestivum L.) within a narrow range of enriched amylose content (36–43%). For these starches, which come from a heterogeneous genetic background, SAXS analysis of duplicate samples enabled structural information to be obtained about their lamellar architecture where differences in lamellar spacing among samples were only several tenths of nanometer. The SAXS analysis of these wheat starches with increased amylose content has shown that amylose accumulates in both crystalline and amorphous parts of the lamella. Using waxy starch as a distinctive comparison with the other samples confirmed a general trend of increasing amylose content being linked with the accumulation of defects within crystalline lamellae. We conclude that amylose content directly influences the architecture of semi-crystalline lamellae, whereas thermodynamic and functional properties are brought about by the interplay of amylose content and amylopectin architecture.
Two waxy bread wheat lines, KI07Wx1 and KI07Wx2, have been developed by treating cv. Kanto 107 seeds with ethyl methanesulphonate (EMS). About 2, 000 seeds of the cultivar were soaked for 4 hours in 0.5% EMS dissolved in 7% ethanol, and then 2, 000 seeds were sown in a green-house and 10, 634 M2 seeds were obtained from 1, 872 M1 plants. Cross sections of the distal endosperms of 4, 000 M2 seeds were stained with an iodine-potassium iodide solution, and two seeds stained red-brown. Since the M3 and M4 seeds derived from the remaining proximal halves of these two seeds showed the characteristic feature of waxy endo-sperm, the waxy endosperm character was considered to be genetically fixed in these two mutant lines, which were designated as KI07Wx1 and KI07Wx2. The amylose content of endosperm starch from both mutant lines was 0.9%, and no waxy proteins were detected in the starch of either line. The agronomic characters of KI07Wx1 and KI07Wx2 were very similar to those of cv. Kanto 107 grown under field conditions, except for the heading dates of the mutant lines and the 1, 000-grain weight of KI07Wx2. These results indicate that the mutagen treatment of seeds is effective in inducing of waxy, i.e. amylose-free, mutants when a bread wheat cultivar has a single waxy protein in their endosperm starch.
The effect of substitution of waxy-wheat flour (WWF) for common wheat flour, 'Hermes' on dough and baking properties was determined. Flours consisting of 20% WWF and 80% Hennes (20 WWF) and 40% WWF and 60% Hermes (40 WWF) were used. Two other mixed flours were prepared for comparison: one consisted of 20% Chinese spring flour (CSF) and 80% Hennes (20 CSF) and the other of 40% CSF and 60% Hennes (40 CSF). Breadcrumbs became softer with increasing WWF substitution, and harder with increasing CSF substitution. From cross sections of these breads from 20 WWF and 40 WWF, the partial substitution of WWF for Hermes was considered favorable for baking results. Especially, 40 WWF made larger loaves and improved glutinous texture, such as the chewing property or adhesiveness of breadcrumbs, as compared with Hermes alone. DSC data showed that WWF retarded the staling of breadcrumbs during storage and also accelerated the refreshing of breadcrumbs with softness and glutinous texture after reheating. Substitution of WWF decreased the setback of viscosity under the holding temperature and suppressed the gelation of starch under cooling, both of which improved the pasting property of starch. In addition, WWF appeared to suppress the formation of an insoluble network structure of starch during cooling, which improved the tolerance of gelatinized starch to the retrogradation. These results indicate that the partial substitution of WWF for common flour improved the softness and glutinous texture of breadcrumbs and retardation of staleness. Consequently, WWF might have applications in practical baking.
A simple straight-line relationship between iodine staining and the average chain length (CL) of the linear amyloglucans has been derived utilizing the published data of Baldwin et al. [J. Am. Chem. Soc.66, 111 (1944)], Bailey and Whelan [J. Biol. Chem.236, 939 (1961)], Szejtli et al. [Biopolymers5, 5 (1976)], Pfannemüller et al. [Biopolymers10, 243 (1971)], and Banks et al. [Carbohydr. Res.17, 25 (1971)]. The iodine staining characteristics—the wavelength of maximal optical absorbance (λM); the maximal absorbance (AM); and the iodine binding capacity (Ib) per chain—are all linearly related to the chain length. As an example, Ib per chain is linearly related to the CL and in the formula of a straight line: Y = nX − c where Y equals Ib per chain (or Ib × CL); X equals the CL, n is the slope, and c is the intercept of the Y-axis by the straight line. Thus, CL and Ib are related as follows: CL = c/(n − Ib) Using the data of Banks et al., it was found that the slope was not affected by changes in temperature, but the Y-intercept became less negative with decreasing temperature. Thus, the number of glucose residues per iodine molecule in the helix did not change, but shorter chain length species could complex with the iodine, and a larger fraction of each chain could form the helical configuration with iodine as the temperature was reduced. These findings suggest that the CL and therefore the number-average degree of polymerization and the number-average molecular weight of the unbranched amyloglucans could be determined by AM, Ib or λM measurements after standardization under precise experimental conditions.
The large (A-type) and small (B-type) wheat starch granules were characterized and used for hydroxypropylation and cross-linking. The A-type granules contained higher amylose content and exhibited lower gelatinization temperature and higher transition enthalpy as compared with the B-type granules. Hydroxypropylated starches (HS) and hydroxypropylated and cross-linked starches (HCS) from the A-type granules were more hydroxypropylated than were those from the B-type granules. Moreover, HS and HCS of A-type granules had higher swelling power and resulted in greater paste consistency and clarity than HS and HCS of B-type granules. Hydroxypropylation of starches increased swelling power, paste consistency and clarity. In contrast, cross-linking of the HS inhibited granule swelling and reduced paste viscosity and clarity. Both the HS and HCS decreased the gelatinization temperature but improved freeze–thaw stability as compared with the native starches.
A starch granule protein, SGP-1, is a starch synthase bound to starch granules in wheat endosperm. A wheat lacking SGP-1 was
produced by crossing three variants each deficient in one of three SGP-1 classes, namely SGP-A1, -B1 or -D1. This deficient
wheat (SGP–1 null wheat) showed some alterations in endosperm starch, meaning that SGP-1 is involved in starch synthesis.
Electrophoretic experiments revealed that the levels of two starch granule proteins, SGP-2 and -3, decreased considerably
in the SGP-1 null wheat though that of the waxy protein (granule-bound starch syn- thase I) did not. The A-type starch granules
were deformed. Apparent high amylose level (30.8–37.4%) was indicated by colorimetric measurement, amperometric titration,
and the concanavalin A method. The altered structure of amylopectin was detected by both high- performance size-exclusion
chromatography and high-performance anion exchange chromatography. Levels of amylopectin chains with degrees of polymerization
(DP) 6–10 increased, while DP 11–25 chains decreased. A low starch crystallinity was shown by both X-ray diffraction and differential
scanning calorimetry (DSC) analyses because major peaks were absent. Abnormal crystallinity was also suggested by the lack
of a polarized cross in SGP-1 null starch. The above results suggest that SGP-1 is responsible for amylopectin synthesis.
Since the SGP-1 null wheat produced novel starch which has not been described before, it can be used to expand variation in
wheat starch.
The practical applications of flour from waxy (amylose-free) hexaploid wheat (Triticum aestivum L.) were assessed. The applications evaluated were bread, cakes, white salted noodles, and pasta for gyoza. An excessive addition of waxy hexaploid wheat flour to total wheat flour (>20%) resulted in poorer functional properties (sticky, lumpy, or less crispy textures) in almost every end use product. However, incorporation of <20% waxy hexaploid wheat flour, produced considerable improvement in shelf-life characteristics. After one day of storage, the bread from flour including waxy hexaploid wheat flour maintained moistness, softness, and stickiness. This application of waxy hexaploid wheat flour as an antistaling ingredient was also confirmed in cake products. Tests were also conducted on alimentary pasta products. In alimentary pasta, waxy hexaploid wheat flour was most effective when utilized for frozen fried dumplings (gyoza). By using flour including 30 of 50% waxy hexaploid wheat flour, the problem of firmness was solved without other ingredients. In conclusion, flour from waxy hexaploid wheat may be useful in developing more increased staling- and freezing-tolerant grain-based foods. Starch properties could be responsible for these improved characteristics.
Cereal Chem. 75(6):887-896 Three high-amylose maize starches (HAS) and a common corn starch (CCS) were subjected to differential alcohol precipitation using isoamyl alcohol and 1-butanol to obtain fractions designated as amylose (AM), amylopectin (AP), and intermediate material (IM). For each starch, IM had a blue value and an iodine binding wavelength maximum (λmax) between the λmax of the respective AM and AP. Size-exclusion chromatography (SEC) showed similarities in the AM from CCS and HAS. HAS AP had higher blue values and iodine binding λmax values than CCS AP. SEC of the intact HAS AP and IM both showed large proportions of material eluting after the void volume (45-85%) when compared to CCS AP and IM. Chain length (CL) distributions of debranched AP and IM indicated that these fractions from each starch were highly branched, and that AP had a shorter average chain length than IM. Consequently, the differential precipitation behavior of the HAS AP and IM appears dependent on general branching structure rather than size. We conclude that in both CCS and HAS, AP and IM are subsets of the branched molecules with AP as the predominant fraction. For HAS, AP and IM include molecules of a size typical for AM and contain a higher proportion of chains that are longer than those of CCS AP. Differential alcohol precipitation is a useful method of separating amylose, amylopectin, and intermediate material from HAS.
Cereal Chem. 79(4):491-495 The dough properties and baking qualities of a novel high-amylose wheat flour (HAWF) and a waxy wheat flour (WWF) (both Triticum aestivum L.) were investigated by comparing them with common wheat flours. HAWF and WWF had more dietary fiber than Chinese Spring flour (CSF), a nonwaxy wheat flour. Also, HAWF contained larger amounts of lipids and proteins than WWF and CSF. There were significant differ- ences in the amylose and amylopectin contents among all samples tested. Farinograph data showed water absorptions of HAWF and WWF were significantly higher than that of CSF, and both flours showed poorer flour qualities than CSF. The dough of WWF was weaker and less stable than that of CSF, whereas HAWF produced a harder and more viscous dough than CSF. Differential scanning calorimetry data showed that starch in HAWF dough gelatinized at a lower temperature in the baking process than the starches in doughs of WWF and CSF. The starch in a WWF suspension had a larger enthalpy of gelatinization than those in HAWF and CSF suspensions. Amylograph data showed that the WWF starch gelatinized faster and had a higher viscosity than that in CSF. The loaves made from WWF and CSF were significantly larger than the loaves made from HAWF. However, the appearance of bread baked with WWF and HAWF was inferior to the appearance of bread baked with CSF. Bread made with WWF became softer than the bread made with CSF after storage, and reheating was more effective in refreshing WWF bread than CSF bread. Moreover, clear differences in dough and bread samples were revealed by scanning electron microscopy. These differences might have some effect on dough and baking qualities.
In our wheat breeding program to introduce the low amylose character of Tanikei A6099 to elite lines, five waxy lines were unexpectedly obtained from 249 doubled haploid lines of the F1 hybrid of Saikai 168 x Tanikei A6099. The amylose content of all the waxy lines was <1% and the blue value was <0.1. Starch granule-bound proteins were extracted and subjected to modified sodium dodecyl sulfate polyacrylamide gel electrophoresis. The waxy lines lacked the Wx protein. Starch paste viscosity measurements gave pasting profiles of waxy wheat starch that were quite different from those of nonwaxy wheats but similar to those of waxy maize. However, the peak viscosity of waxy wheats was much higher than that of the waxy maize.
Study of A type starch granules from immature wheat endosperm with the scanning electron microscope has led to a developmental sequence being suggested. Evidence is provided which indicates that the initial minute spherical granule becomes a “nucleus” which is progressively surrounded in the equatorial plane by a continually enlarging structure which resembles two lips with a furrow between them. When the lips have completely surrounded the “nucleus” the thickness and diameter of the granule continue to increase in such a way that the furrow becomes shallower and is present in the mature biconvex structure only as a shallow score.
The influence of water content on the gelatinization of wheat starch was examined by differential scanning calorimetry. Three endothermic transitions were observed when starch was heated to 140 °C with 35 to 80% (w/w) water. The temperature of the second and third endotherms and the enthalpies of the first and second endotherms vary with water content.
Die Wirkung des Wassergehaltes auf die Verkleisterung von Weizenstärke Der Einfluß des Wassergehaltes auf die Verkleisterung von Weizenstärke wurde mit Hilfe der Differential-Raster-Kalorimetrie untersucht. Wenn Stärke mit 35 bis 80% (w/w) Wasser auf 140 °C erhitzt wurde, konnten drei endotherme Übergänge beobachtet werden. Die Temperatur der zweiten und dritten Endothermen und der Enthalpien der ersten und zweiten Endothermen verändert sich mit dem Wassergehalt.
A series of linear, amylose oligomers has been synthesized enzymically to yield samples having the number-average degree of polymerisation, , in the range 22 to 134. The interaction of these materials with iodine has been studied. The wavelength of maximal absorption of the iodine complex, λmax, has been found to be related to by the Langmuir isotherm: .Differential, potentiometric titration of iodine has shown that the iodine-binding capacity of the linear oligomers is a function of both and temperatures. The enthalpy of the iodine uptake has been measured, and found to be a function of for values of <200.
Three commercial kudzu starches from Vietnam, Japan and Korea were used to determine chemical compositions, isoflavone compounds, fine structure and physicochemical properties. The kudzu starch from Vietnam had polygonal granules, whereas the kudzu starches from Japan and Korea contained both polygonal and spherical granules. Total protein, lipid, ash and phosphorus contents present in these kudzu starches were less than 1% (starch basis). The kudzu starch from Vietnam and Korea contained both daidzein and daidzin, whereas the kudzu starch from Japan had only daidzein. These starches had similar actual amylose contents (22.2–22.9%). However, λmax, blue value and apparent amylose contents of the kudzu starch from Vietnam were lower than those from Japan and Korea. Amylose molecules of the kudzu starch from Vietnam had the largest average degree of polymerization (DPn) and number of chains (NC), followed by the kudzu starches from Japan and Korea. Amylopectin molecules of the kudzu starch from Vietnam also had the largest DPn and NC, followed by the kudzu starches from Korea and Japan. X-ray diffraction patterns of the kudzu starches from Vietnam, Japan and Korea were A-type, C-type and B-type, respectively. The kudzu starch from Vietnam was found to have the specific characteristics such as significantly high gelatinization temperature, transition enthalpy and degree of crystallinity as compared to the kudzu starch from Korea and Japan.
Cereal Chem. 78(2):111–115 Amylose and amylopectin were prepared from large, medium, and small granule starches of classified waxy barley flour, and their fine structures were investigated. The amylose content had a wide distribution range (≈1.4–9.4%). Number-average degrees of polymerization (DP n) of the amyloses were similar among the samples (≈1,200–1,300). But number of chains per molecule (NC) decreased from the surface to the center (≈6–10 chains). DP n of the amylopectins varied from 4,657 to 14,604; decreased in the order of large, medium, and small granules in same fractions of the grain; and increased from the surface layer to the center. Longest chains (LC) were not found in any of the amylopectin molecules. The large amylopectin molecule had more long chains and fewer A chains than the small molecule. The amylose content had definite effects on the transition temperature range and crystal formation of the starch granules. There were positive correlations between DP n of the amylopectin and rela-tive crystallinity (γ = +0.69) and enthalpy value (γ = +0.80), respectively. These findings may help to elucidate biosynthesis mechanism of starch.
Waxy and high-amylose wheats are genetically modified cultivars produced firstly in Japan. The physicochemical properties of waxy and high-amylose wheat starches were investigated and compared to those of normal bread-wheat starch. The waxy wheat starch (˜ 1% of amylose) showed higher gelatinization temperature, transition enthalpy and crystallinity of granules than the normal and high-amylose wheat starches. The paste of waxy wheat starch had higher peak viscosity and swelling power, lower pasting temperature and final viscosity, which are favorable for producing Japanese white-salted noodles (Udon) of high-quality. In contrast, the high-amylose wheat starch had higher amylose content (37.5%), blue value and wavelength of maximal iodine absorption but lower gelatinization temperature and crystallinity than the normal wheat starch. The paste of high-amylose wheat starch had lower peak viscosity, breakdown and final viscosity than that of the normal wheat starch. These properties of the high-amylose wheat starch contributed to improve textural properties of noodles which were similar to durum wheat noodles.
The hierarchical granule structure of starches with different amylose content extracted from winter wheat was investigated
using light microscopy (LM), scanning electron microscopy (SEM), wide-angle X-ray diffraction (WAXS), high-sensitivity differential
scanning calorimetry (HS DSC) and different thermodynamic approaches. Morphology (size, size distribution and shape), crystallinity
of native granules with different amylose content (1.5-39.5%), as well as the cooperative melting unit, thickness of crystalline
lamellae, heat capacity drop related to hydration during melting of native granules, and thermodynamic parameters related
to the surface of crystalline lamellae were determined. The relationship between structure and thermodynamic properties of
mutant wheat starches is discussed.
To characterize superior genotypes for the white Japanese noodle, endosperm starch properties including amylose content, flour peak viscosity and starch-granule bound Waxy (Wx) proteins were compared using several cultivars preferred for noodle manufacture. Amylose contents from three seasons trials and flour peak viscosity from two seasons trials varied among cultivars. Low amylose content was a common property in the noodle cultivars, whereas a high peak viscosity was not always the case. When the Wx proteins were analyzed by sodium dodecylsulfate polyacrylamide gel electrophoresis, a clear reduction in the amount of low molecular weight protein or a lack of the high molecular weight protein occurred in the noodle cultivars. Segregation of Wx proteins was detectable in a B1F1 population, indicating that the Wx protein analysis has a potential as a surrogate of selecting low amylose genotypes in early generations.
The distributions of chain lengths in the amylopectins of starches from 20 species (11 A-, 6 B-, and 3 C-type) were characterised by h.p.l.c. in terms of the relationship between the molecular structure of the amylopectin and the crystalline structure of the starch granule. The weight-average chain-lengths of the amylopectins of the A-, B-, and C-type starches were in the ranges 23–29, 30–44, and 26–29, respectively. Gel-permeation chromatograms of the amylopectins debranched with isoamylase showed bimodal distributions of fractions containing long and short chains for 17 specimens (including corn, rice, potato, etc.) and trimodal distributions, of which the fraction containing short chains had twin peaks, for wheat, tapioca, and tulip amylopectins. The correlation coefficients between the average chain-lengths of amylopectins and the fractions of long and short chains and the ratio of the fractions of short and long chains by weight were 0.90, 0.69, and −0.95, respectively. In general, amylopectin molecules of A-type starches have shorter chains in both the long- and short-chain fractions and larger amounts of the short-chain fractions than those of the B-type starches. The chain lengths of amylopectins of the C-type starches were intermediate and it is inferred that these starches possibly yield any type of crystalline structure depending on the environmental temperature and other factors, whereas the A- and B-type starches are insensitive to temperature.
Convenient and sensitive methods are described for analyses of the reducing and non-reducing residues of amylose. The multi-branched nature of amylose samples from several plant sources was revealed quantitatively by these methods. Pseudomonas isoamylase partially (30%) split the branch linkage of potato amylose. The concurrent action of Aerobacter pullulanase and sweet-potato beta-amylase hydrolysed the amylose completely.
The fine structure of wheat amylopectin was analyzed by means of a new enzymic method, as well as by conventional methods. Its general properties were found to be similar to those of rice amylopectin with intermediate iodine affinity, but the chain-length distribution was clearly distinguishable from that of rice amylopectins. The B chain, as defined by Peat and co-workers [J. Chem. Soc. (1956) 3025], was classified into Ba and Bb chains on the basis of whether A chains were bound (Ba) or not bound (Bb), and the number of A chains bound to a Ba chain was determined from the ratio of non-reducing to reducing residues of the stepwise degradation products of the amylopectin with β-amylase, isoamylase, and β-amylase. A Ba chain was found to carry 2.1 A chains on average, but the longer Ba chains bound increased numbers of A chains (up to four). The A: B and the Ba: Bb chain ratios were found to be 1.26:1 and 1.5:1, respectively, indicating that ∼40% of the B chains carried no A chains.
A method for the purification of amylose from rice starch has been developed. The critical step was the removal of insoluble amylopectin-like contamination from crude amylose in water at 50° by ultracentrifugation at 100,000g for 1 h. The conventional autoclaving procedure was avoided. Gel-permeation chromatography and h.p.l.c. indicated the amylose specimens prepared from indica and japonica rice starches to be pure. The iodine affinities and blue values of the specimens were 20.0–21.1 g/100 g and 1.40–1.47, respectively. The amyloses had number-average d.p. (n) values of 980–1110, average chain-lengths of 250–370, and beta-amylolysis limits of 73–84%, indicating them to be slightly branched molecules with 2–5 chains on average. The weight-average d.p. (w) values were 2750–3320, and the high w/n values (2.6–3.4) suggested broad distributions of molecular weights.
The Waxy (Wx) protein has been identified as granule-bound starch synthase (GBSS; EC 24.1.21), which is involved in amylose synthesis in plants. Although common wheat (Triticum aestivum L.) has three Wx proteins, "partial waxy mutants" lacking one or two of the three proteins have been found. Using such partial waxy mutants, tetra- and hexaploid waxy mutants with endosperms that are stained red-brown by iodine were produced. Both mutants showed loss of Wx protein and amylose. This is the first demonstration of genetic modification of wheat starch.
Table 4 Fine structure of amylose fractionated from several Australian high-amylose wheat starches
- P V Hung
Table 4 Fine structure of amylose fractionated from several Australian high-amylose wheat starches P.V. Hung et al. / Carbohydrate Polymers 71 (2008) 656–663