Amylose Content Of Starch Research Articles

Effect of process conditions and amylose/amylopectin ratio on the pasting behavior of maize starch: A modeling approach

The effects of different process conditions on the pasting behavior of the 14%, w/w suspensions of high amylose, waxy and normal maize starches at mixing speeds of 50, 160 and 250 rpm with the heating rates of 2.5, 5 and 10 °C/min were investigated. In addition, the impact of the starch mixture with an amylose-amylopectin ratio of 0–70% at 160 rpm and a heating rate of 5 °C/min on the pasting parameters was studied. According to the results, when stirring speed decreased from 250 rpm to 50 rpm, the peak viscosity dramatically increased. Furthermore, both heating and stirring rates significantly affected the pasting properties (p < 0.05). The amylose content of maize starch had a negative correlation with peak viscosity, trough viscosity, breakdown viscosity, final viscosity, and setback viscosity. Besides, syneresis values decreased as amylose content decreased from 70% to 0%. According to the kinetic modelling of pasting curves, starch coefficients were found to be higher than 1 for all starches, indicating that the penetration of water into starch granules increased granule swelling rate. The findings of the present study confirmed that both process conditions and amylose/amylopectin ratio can be optimized without necessity of starch modification to obtain the products with the desired quality.

Effect of γ-radiation on physico-chemical, morphological and thermal characteristics of lotus seed (Nelumbo nucifera) starch

Native and gamma (γ) irradiated lotus seed starches were studied for their physicochemical, thermal, pasting and morphological properties. Upon gamma irradiation of 5, 10, 15 and 20 kGy, amylose content of starches was decreased as the dose of irradiation was increased. Lotus seeds starch granules had bimodal size distribution varying in size from small to large. Observation under scanning electron microscope (SEM) showed that at low dose of irradiation (5, 10kGy), no significant changes were observed in shape and size. However, minor alterations were notice during treatment of 15kGy and 20 kGy, which included roughness. Irradiation significantly decreased the pasting properties (peak, trough, final and setback viscosities) of the starch. For native starch, To, Tp, and Tc of 137.44 °C, 138.29 °C and 143.21 °C and 169.51 °C, 169.72 °C, and 177.73 °C respectively was observed for first and second peak. Upon irradiation, the gelatinization temperatures were decreased. The irradiated starch showed no change in diffraction pattern compared to native lotus seed starch but a dose-dependent decrease in relative crystallinity was observed.

Structure and properties of soft rice starch

Pasting and rheological properties of starch from soft rice and two traditional rice varieties were analyzed. Soft rice starch was found to have a low pasting temperature of 67.2 °C, with a high system viscosity, including peak and trough viscosity. The storage modulus and loss modulus of soft rice starch were high and showed good viscoelasticity. The amylose content of soft rice starch was found to be 11.3%, classifying it was low amylose content type. Compared with japonica rice starch, soft rice starch had lower solubility but higher swelling power, gel consistency, and water binding capacity. The medium particle size and volume mean particle size of soft rice starch were the highest. The average molecular weight of soft rice starch was 5.4 × 107. The molecular density and proportion of short amylopectin side chains, with a range of 6–12, were the highest among all varieties tested. These findings provide a theoretical basis for the processing of soft rice starch and breeding of high-quality rice.

Diversity and relationship among grain, flour and starch characteristics of Indian Himalayan colored corn accessions.

The present study examined the diversification and relationship among grain, flour and starch characteristics of thirty eight differently coloured corn accessions. The differences among accessions were more pronounced due to heterogeneity in genetic traits than color. Colour properties were positively related with phenolics and antioxidant activity. K, Ca, Zn, Mg, Na, Cu, Fe and Mn were the prominent minerals present in accessions. Accumulation of 10 polypeptides, ranging from 10 to 95kDa was also evaluated. HPLC analysis showed the presence of gallic acid, Catechin, caeffic acid, chlorogenic acid, protocatechuic acid, p-coumaric acid, vanillic acid, quercetin, sinapic acid, ferulic acid, reservatrol and luteolin in flours. Accessions had higher proportions of amino acids, citrulline, arginine, GABA, phenylalanine, isoleucine, tyrosine, threonine, glycine. Starch granules with different particle size showed angular structure.Final viscosity, set back viscosity and crystallinity positively related to amylose content of starch. Starches with A-type crystalline pattern showed variability in thermal properties. The results of this study showed significant relationship between DPPH and total phenolic content, thermal properties, amylose content and crystallinity among various corn germplasm. These will be helpful for selection of appropriate accessions having required characteristics not only for food applications but also for non-food ones.

Comparative studies on physicochemical properties of total, A- and B-type starch from soft and hard wheat varieties

Starch from soft wheat and hard wheat varieties was evaluated for physicochemical properties, including pasting and retrogradation properties, swelling power and solubility, and granule morphology. Grain hardness index of soft and hard wheat varieties ranged from to 25 to 35, and 71 to 82, respectively. Soft wheat varieties showed a larger proportion of total starch (TS) and A-type starch (AS), and a smaller proportion of B-type starch (BS). The amylose content of starch from hard wheat varieties was significantly higher than that from soft wheat varieties. Starch from soft wheat varieties exhibited higher pasting viscosity, transmittance, swelling power, and smaller crystallinity as compared to starch from hard wheat varieties. BS from hard wheat exhibited the lowest average breakdown and setback viscosity, hardness, adhesiveness, and fracturability. AS exhibited the highest pasting viscosity, better transparency, gel properties, freeze-thaw stability, swelling power, clearer “Maltese cross”, and higher crystallinity, whereas BS exhibited the highest gelatinization temperature, better gel stability and solubility. The study might broaden the recognition of starch from different wheat varieties, and provide a theoretical basis for wheat breeding and the potential utilization of different types of wheat starch and flour.

Physicochemical, pasting, and rheological properties of pearl millet starches from different cultivars and their relations

Physicochemical, pasting, and rheological properties of pearl millet starches were studied and correlations among these properties were calculated. Amylose content, swelling power, and solubility of starches varied from 11.57 to 21.93%, 11.11 to 17.91 g g−1 and 12.20 to 15.20%, respectively. Volume% of starch granule size less than 10 µm varied from 36.23 to 48.34%, and 12.16 to 18.75% for above 20 µm size of granule. Peak viscosity of starches varied from 1291 to 1853 mPa·s, cv. RHB-173 had the highest value. Frequency sweep measurement of starch pastes revealed higher magnitude of G′ as compared to G″ with increase in to, indicating visco-elastic behaviour. Yield stress (σo), consistency index (K), and flow behaviour index (n) were observed as 40.73 to 115.72 Pa, 0.729 to 3.998 Pa·s, and 0.604 to 0.964, respectively. Starch pastes from cultivars studied showed shear thinning behaviour.

Comparison of structural features of reconstituted doughs affected by starches from different cereals and other botanical sources

Starch, as the main component of flour products, determines the physicochemical properties of dough. This work investigated the relationship of the physical properties of seven types of starches from various cereals with the structural features of reconstituted dough. Results of mixing and tensile properties analysis and scanning electron microscopy displayed that rice reconstituted flour exhibited maximum water absorption; pea reconstituted flour had higher dough stability; sweet potato dough had higher tensile resistance; highland barley dough had the greatest extensibility. Moisture distribution analysis revealed that various model dough showed remarkably different water distribution, which was distributed at T21 (0.07–0.11 ms), T22 (0.8–2.66 ms) and T23 (10.0–20.82 ms). Correlation analysis indicated that large starch granules associated with good dough stability; amylose content of starch positively affected tensile resistance of dough; crystallinity of starch showed negative effects on water absorption; starch with higher crystallinity associated with greater dough stability.

Microstructure, gelatinization and pasting properties of rice starch under acid and heat treatments

Microstructure of starch plays a vital role in the physicochemical properties. In this study, the microstructure, gelatinization and pasting properties of rice starches after acid, heat and acid-heat treatments were investigated. In our findings, molecular weight and size, amylopectin chain length distribution, degree of branching, amylose content, relative crystallinity, and hot water-solubility of rice starch were varied significantly after acid-heat treatment, showing a synergy between acid and heat. Correspondingly, acid-heat treatment markedly changed gelatinization and pasting properties of rice starch by sharply decreasing gelatinization and pasting temperatures as well as pasting viscosities. Pearson correlation analysis was performed, showing that molecular weight, size, amylopectin chain length distribution, and amylose content were significantly correlated to gelatinization temperatures, and crystallinity was remarkably correlated to gelatinization enthalpy. As for pasting properties, molecular weight and size as the major factors were substantially correlated to pasting viscosities and pasting temperature. This study provides a structure-property correlation for acid-heat treated rice starch, giving scientific basis for the application of starch in food industry.

Modified tuber starches as potential stabilizer for food-grade Pickering emulsions

The application of modified tuber starches in particle-stabilized emulsions was studied to obtain surfactant-free emulsions, called Pickering emulsions. Three different starches, namely, potato (P), sweet potato (S) and tapioca (T) starches were modified using dry-heat treatment (HD, 120°C, 150 mins), hydrothermal treatment (HM, 50°C, 30 mins), OSAmodification (OSA, 2.9%) and hydroxypropylation (HP, 2 mL of 20% propylene oxide) before being used as stabilizer for stabilizing emulsion. The physicochemical properties of the starches and the characteristics of the stabilized emulsion were studied. Potato OSAtreated starch (POSA) had significantly higher degree of substitution (DS) (DS = 0.0154) than SOSA (DS = 0.0081) and TOSA (DS = 0.0083). For the starches undergone treatment of hydroxypropylation, SHP had the highest molar substitution (MS) value of 0.20, followed by PHP (0.11) and THP (0.10). The amylose content of starches reduced significantly after all modifications (HD, HM, OSA, and HP). All OSA-treated starch (POSA, SOSA, and TOSA) had higher fat binding capacity compared to their native and starches that modified using different treatments (HD, HM, and HP). Based on the emulsification index values and optical microscopic images, all starch particles were able to stabilize emulsions except for SC, SHM, TC, and THM. Optical microscopic images showed that the starch particles accumulated and formed a densely packed layer at the oilwater interface. At the starch concentration of 400 mg/mL oil, emulsion stabilized by dryheated potato starch and all hydroxypropylated-starch-stabilized emulsions had a high emulsification index value of 1. Significantly highest viscosity was noticed from the emulsion stabilized by POSA. Overall, by comparing the physico-chemical properties of the modified starches and the characteristics of emulsions stabilized, potato OSA-treated starch (POSA) had the best emulsifying ability.

Influence of organic and inorganic nutrients on yield, physicochemical properties and cooking quality of seeragasamba rice

Field experiments were conducted during samba seasons of 2017-2018 and 2018-2019 to study the effect of organic manures and inorganic nutrients on yield, physicochemical and cooking quality of Seeragasamba rice. The experiments were conducted in sandy clay loam with pH around 7.5. Fourteen treatments comprising different sources of organic manures and inorganic nutrients were replicated thrice under RBD. The treatments are as follows: T1- 100%N through Green Manure, T2-75%N through Green Manure+25%N through RDF, T3-50%N through Green Manure+50% N through RDF, T4 -100%N through FYM, T5-75% N through FYM+25% N through RDF, T6-50% N through FYM+50% N through RDF, T7-100% N through Composted Poultry Manure, T8-75%N through Composted Poultry Manure+25%N through RDF, T9-50% N through Composted Poultry Manure+50%N through RDF, T10-100%N through Vermicomposted Pressmud, T11- 75% N through Vermicomposted Pressmud+25% N through RDF, T12-50% N through Vermicomposted Pressmud + 50% N, T13-RDF @ 56:37:37 NPK Kg/ha through in organic and T14 - Control (No Nitrogen). The results revealed that in both samba seasons, the highest grain yield was obtained in (T3) application of 50% N through green manure + 50% N through RDF and it was followed by the (T12) application of 50% N through vermicomposted pressmud + 50% N through RDF. However, both treatments were found to be on par with each other. The milling recovery, head rice recovery, protein and starch amylose content were also found to be higher in these treatments as compared to others. The cooking quality evaluated interms of increased length and breadth of cooked rice were also enhanced in these treatments. The sensory evaluation attributes viz., colour, taste, texture and overall acceptability were also increased in T3 and T12.

Physicochemical properties of enzymatically prepared resistant starch from maize flour and its use in cookies formulation

ABSTRACT The current study was aimed to enzymatically modify maize flour by using amylase and pullulanase in combination for increasing the yield of resistant starch type III (EM-RSIII). The enzymatic treatment imparts unique desired physicochemical properties to the maize flour including resistant starch content, amylose content, milk, oil, and water interaction ability. The sensory analysis was performed by distributing questioners among individual and results were interpreted by 5-point hedonic scale. Result indicated an increase in the stability, amylose content, and milk absorption capacity of maize flour, while a decrease in swelling power, water absorption, and oil absorption capacity. The enzymatic treated maize flour led to the transformation of amorphous native structure into a crystalline structure which was confirmed by light microscopy, scanning electron microscopy, X-ray diffractograms analysis, and in vitro digestibility of EM-RSIII. The EM-RSIII rich maize flour was used in cookies preparation and a significant difference in palatability and color parameters was observed. Crispiness and texture of EM-RSIII containing cookies was increased due to its low swelling power, water absorption, and oil absorption capacity. The sensory analysis showed that consumers depicted the highest acceptability of EM-RSIII supplemented cookies specifically for its appearance, sharp aroma, texture and accepted as nutritionally important food item for consumers.

Extraction and characterization of native starch obtained from the inhambu tuber.

Starch is the main carbohydrate consumed by humans, obtained from many vegetable sources and known for its non-toxicity, applications and low cost. The aim of this work was the extraction and study of characteristics of non-conventional starch arising from inhambu (Dioscorea trifida L.). Chemical, physicochemical, thermal, morphological, structural and technological properties were evaluated. The starch yield percentage obtained from the extraction, starch and amylose contents of inhambu starch were considerably high, 22.76%, 84.56% and 36.82% respectively. Native starch presented high purity due the low ash, protein and fat content. The thermogravimetric analysis shown 69% weight loss in a 293.12-476.59°C temperature range and the endothermic peak was at 100.0°C. The starch granule morphology shown spherical shapes and smooth surfaces and size ranging from 5.06 to 14.59µm. Considering the unique starch characteristics, its application in different industrial sectors can be foreseen.

How starch-g-poly(acrylamide) molecular structure effect sizing properties

The effect of starch-g-poly(acrylamide) (S-g-PAM) molecular structure on sizing properties has been investigated. S-g-PAMs were synthesized with the catalysis of horseradish peroxidase (HRP) and Fourier transform infrared (FT-IR) confirmed the acrylamide (AM) units had been successfully grafted on starch chains. Structural parameters, including degree of branching (DB), degree of substitution (DS) and grafting ratio (GR) were characterized by 1H nuclear magnetic resonance (1H NMR), and were correlated with sizing properties of apparent viscosity, adhesion to cotton yarns and film mechanical properties. The apparent viscosity of S-g-PAMs has no obvious correlation with DB and DS (or GR), as the amylose content of the native starch might have more influence on the viscosity of grafted starches. DS (or GR) values of grafted starches have a positive relationship with the tensile strength of sized cotton yarns and are negatively related with tensile strength of starch film. These results can provide guidance in the section of starch with improved sizing properties.

Physicochemical properties and rheological behavior of flours and starches from four bean varieties for gluten-free pasta formulation

Abstract The rheological behavior of gluten-free flour dispersions from four pulse market classes, including great northern, navy, red kidney (Phaseolus vulgaris L.), and garbanzo beans (Cicer arietinum) were evaluated and compared to soft wheat as a gluten-containing control. Their starches were isolated and the relationships between flour behavior and starch characteristics were studied. Soft wheat (56%) and garbanzo (39%) flours presented higher starch contents than the Phaseolus vulgaris beans (33–35%), which resulted in the development of stronger gel network structures. It was found that starch amylose content and granule size affected the swelling and pasting properties of both starches and flours. Rheology tests suggested that garbanzo and navy bean flours developed the strongest structures among the gluten-free samples included. Therefore these were chosen to develop gluten-free pasta. The cooking and texture parameters of these pastas were also studied and compared with soft wheat pasta.

Effect of Amorphization Methods on the Properties and Structures of Potato Starch‐Monoglyceride Complex

Abstract Recently, starch‐based fat replacers (FRs) have emerged as unique ingredients, possessing few calories and high vascular scavenger function without adverse organoleptic changes. Here, a two‐step modification method for the development of a starch‐based FRs is reported. First, native potato starch is amorphized by grinding, alkali and ethanol treatment. Then, the amorphized starch is complexed with monoglyceride. The results show that alkaline amorphous potato starch (AAPS) has the best emulsifying activity; ethanol amorphous potato starch complex (EAPSC) has the highest content of resistant starch (RS) (21.49%), while grinding amorphous potato starch (GAPS) retains the granular structure of the original starch best. The amorphization reduces the amylose content of starch, leading to reduced swelling power and increased digestibility. Complexation, on the other hand, is more like attaching a layer of the hydrophobic membrane. Combined with DSC and XRD, amorphization reduces the value of enthalpy and crystallinity, while the complexation process does the opposite. Overall, EAPSC is the best candidate for novel FRs, due to its greater emulsion stability and enzyme resistance. The experimental results provide a theoretical basis for the application of a novel potato starch‐monoglyceride complex in foods such as cakes and snack fillings.

Relationships between transparency, amylose content, starch cavity, and moisture of brown rice kernels

Rice with low amylose content (AC) is popular due to the unique eating and cooking quality, but its transparency is poor. It is unclear why low AC rice has poor transparency until now. In this study, the transparency and microstructure of brown rice kernels were investigated in rices with different ACs. Chalkiness of endosperm resulted from the loosely packed starch granules, and existed in rice kernels with low and high moisture. However, dry kernels with low AC were opaque or dull due to the cavities in the center of starch granules, and could become transparent gradually with the increase of moisture. For rices with the same genetic background but different ACs, the cavity size was negatively correlated with AC, and the transparency of dry kernels was significantly correlated positively with AC and negatively with cavity size. The transparency of kernels was positively correlated with moisture of kernel, and the effect of moisture on transparency was significantly correlated positively with starch cavity size and negatively with kernel AC. The above results showed that the transparency of low AC rice was remarkably influenced by cavity size and AC of starch, and could be regulated through controlling the moisture of kernel.

Understanding the structural and digestion changes of starch in heat-moisture treated polished rice grains with varying amylose content

Although the effects of heat-moisture treatment on starch structures and digestibility have been evaluated, the changes in structures and digestion of starches in heat-moisture treated starch-based food systems with varying amylose contents are not well understood. In the present study, starches isolated from heat-moisture treated polished rice grains were characterized with multi-scale structures and digestibility to reveal the effect of amylose in rice grains on structures and digestibility of starch subjected to heat-moisture treatment. Results indicated that heat-moisture treatment contributed to the partial gelatinization of starch granules, but also significantly reinforced the molecular interactions between starch molecules and thus increased starch resistance to hydrothermal treatment and enzymes attack. The higher amylose content of the native starch was, the greater reduction in digestion was observed for heat-moisture treated starch. Pearson's correlation matrix showed that the amylose content highly correlated with the changes in structural features (e.g., molar mass, short-range ordered structure, crystalline structure, and lamellar structure) of starches followed by heat-moisture treatment. The amylose promoted the reinforcement of interactions between starch chains during heat-moisture treatment and then significantly contributed to the reduction in starch digestibility.

Corn and cassava starch with carboxymethyl cellulose films and its mechanical and hydrophobic properties

The amylose and amylopectin content of starch influences its functional characteristics and its interaction with other materials. Thus, it is important to study the mechanical strength and hydrophilicity of starch films of different botanical origins to elucidate the influence of their constituents in the interaction with carboxymethyl cellulose (CMC). The objective of this work was to evaluate the mechanical and physico-chemical properties of corn and cassava starch films and their blends with CMC by casting. The addition of CMC improved the tensile, increasing the strength at 206% for its blends with corn starch and 51% for its blends with cassava starch, the rupture stress at 89% and 74%, respectively, and the rupture strain at 381% and 57%, respectively. The elastic modulus presented increase of 20% for corn starch/CMC and 18% for cassava starch/CMC and the water vapor permeability at 48 and 40%, respectively. The corn starch film was more hydrophobic due to its higher amylose content, which contributed to the interaction between starch and glycerol OH groups and CMC COOH groups. This interaction was evidenced by FTIR and contact angle analysis, turning corn starch/CMC films into less hydrophilic material and reducing its water vapor permeability rate, which made this material promising for several applications, including food packaging.

Generation of selectable marker-free soft transgenic rice with transparent kernels by downregulation of SSSII-2

The amylose content (AC) of rice endosperm starch varies from 0 to 35%, and is associated with rice cooking and eating quality. Soft rice has low AC, generally between 6% and 15%, and its eating quality is high whether it is consumed hot or cold. However, the appearance quality of current soft rice cultivars needs to be improved, especially opaque endosperm. Conventional genetic engineering has improved some agronomic traits of soft rice varieties, but not endosperm appearance. In the present study, a RNAi construct of the soluble starch synthase II-2 (SSSII-2) and the hygromycin phosphotransferase (HPT) gene were introduced into an elite japonica rice variety, Kangtiaowuyunjing (KWY8) by co-transformation. Several selectable marker-free (SMF) transgenic lines were obtained, and SSSII-2 expression was significantly downregulated in selected transgenic lines, resulting in lower AC of the endosperm. The physicochemical properties of the transgenic rice kernels, including gel consistency (GC) and rapid visco analyzer (RVA) profile, differed significantly from those of wild-type rice and were similar to those of a soft rice variety, Nanjing 46 (NJ46). These findings indicate that the cooking, eating, and processing qualities of transgenic rice are comparable to those of NJ46. However, the transgenic rice endosperm retained a transparent appearance under low-moisture conditions. Thus, SMF SSSII-2 RNAi rice provides a resource for breeding soft rice with transparent endosperm.

Влияние содержания амилозы в пшеничной муке на процесс черствения и показатели качества хлеба в процессе хранения

Статья посвящена рассмотрению основных аспектов, влияющих на процесс ретроградации крахмала и разработку хлебобулочных изделий длительного хранения. В статье обоснована необходимость разработки данных изделий, направленная на решение, в т.ч. вопросов продовольственной безопасности. Изучены современные подходы к селекции мягкой пшеницы, с целью выведения сортов с низким содержанием амилозы в крахмале. Опытным путем установлено влияние муки из пшеницы сорта waxy на процесс черствения хлебобулочных изделий. В ходе исследований применялись стандартные методы определения амилозы, клейковины в муке пшеничной хлебопекарной 1 сорта, органолептические и физико-химические методы исследования для установления качественных показателей хлебобулочных изделий. Показано, что использование пшеничной муки с низким содержанием амилозы оказывает благоприятное влияние на замедление процесса черствения хлеба и сохранения его потребительских характеристик.&#x0D;