Melting the secrets of gelatinisation temperature in rice

2010 ◽  
Vol 37 (5) ◽  
pp. 439 ◽  
Author(s):  
Rosa P. Cuevas ◽  
Venea D. Daygon ◽  
Henry M. Corpuz ◽  
Leilani Nora ◽  
Russell F. Reinke ◽  
...  
Keyword(s):  
Amylose Content ◽  
Oryza Sativa L ◽  
Length Distribution ◽  
Cooking Time ◽  
Scanning Calorimetry ◽  
Rice Varieties ◽  
Chain Length Distribution ◽  
Chain Lengths ◽  
Major Grouping ◽  
Upper Boundary

Gelatinisation temperature (GT) is one of the key traits measured in programs for breeding rice (Oryza sativa L.). It is commonly estimated by the alkali spreading value (ASV), and less commonly by differential scanning calorimetry (DSC). Using a diverse set of germplasm, it was determined that DSC values associate poorly with ASV, are not correlated with amylose content but correlate with cooking time. Rice varieties are traditionally grouped into three classes of GT based on ASV: high, intermediate and low. However, the distribution of DSC values of 4000 samples shows only two classes: high and low. Large differences in the distributions of chain lengths synthesised by starch synthase IIa (SSIIa) support the two classes as the major grouping, two haplotypes associating with each peak. Each peak of DSC values spanned 10°C. The chain length distribution of the amylopectin molecules from varieties at the upper boundary of each peak showed significantly more chains that span both the crystalline and amorphous lamellae of a cluster than varieties at the other end of that distribution. Improved varieties, classified as intermediate GT by ASV, belong to both of the classes defined by DSC, implying that some enzyme, other than SSIIa is involved in intermediate GT.

scholarly journals Functionality of cassava genotypes for waxy starch

2021 ◽  
Vol 56 ◽  
Author(s):  
Thaís Barbosa dos Santos ◽  
Carlos Wanderlei Piler de Carvalho ◽  
Luciana Alves de Oliveira ◽  
Eder Jorge de Oliveira ◽  
Flávia Villas-Boas ◽  
...  
Keyword(s):  
Amylose Content ◽  
Length Distribution ◽  
Principal Component ◽  
Scanning Calorimetry ◽  
Strong Negative Correlation ◽  
Chain Length Distribution ◽  
Crystallinity Degree ◽  
Waxy Maize ◽  
Waxy Starch ◽  
Paste Viscosity

Abstract: The objective of this work was to select cassava (Manihot esculenta) genotypes from the Brazilian germplasm bank with a functionality similar to that of waxy starch. A total of 881 genotypes were pre-selected using principal component analysis and hierarchical clustering, and their industrial potential was compared with that of the 7745-5WX waxy cassava and the WX-Maize waxy maize clones, both used as references. Two genotypes stood out: BGM0036 and BGM0083. Samples from these four genotypes were characterized by means of amylose content, scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, paste viscosity, and chain-length distribution of amylopectin. The samples presented A-type crystallinity and no statistical differences (p > 0.05) regarding crystallinity degree (25.3 to 30.0), which shows similar proportions of the amylose/amylopectin fractions. No differences were observed in the microstructure of the cassava starches. Initial gelatinization temperature and amylopectin short chains presented a very strong negative correlation, indicating that a lower proportion of short chains of amylopectin results in a higher initial temperature of gelatinization. BGM0036 and BGM0083 show a low final viscosity, close to that of the waxy maize and cassava starches, being an alternative for use in different foods that require stability during freezing.

Natural variation in rice starch synthase IIa affects enzyme and starch properties

2004 ◽  
Vol 31 (7) ◽  
pp. 671 ◽  
Author(s):  
Takayuki Umemoto ◽  
Noriaki Aoki ◽  
Hongxuan Lin ◽  
Yasunori Nakamura ◽  
Naoyoshi Inouchi ◽  
...  
Keyword(s):  
Amino Acid ◽  
Natural Variation ◽  
Oryza Sativa L ◽  
Length Distribution ◽  
Starch Synthase ◽  
Rice Starch ◽  
Nucleotide Polymorphisms ◽  
Cultivated Rice ◽  
Chain Length Distribution ◽  
Starch Properties

The natural variation in starch synthase IIa (SSIIa) of rice (Oryza sativa L.) was characterised using near-isogenic lines (NILs). SSIIa is a candidate for the alk gene regulating the alkali disintegration of rice grains, since both genes are genetically mapped at the same position on chromosome 6 and related to starch properties. In this study, we report that the alkali-susceptible cultivar Nipponbare lacked SSIIa activity in endosperm. However, the activity was detected with NILs having the alk allele of alkali-tolerant Kasalath. SSIIa protein was present even in Nipponbare endosperm, but it was not associated with starch granules at the milky stage of endosperm. Three single-nucleotide polymorphisms (SNPs) predicting amino acid substitutions existed between the cDNA sequences of SSIIa of Nipponbare and Kasalath were genotyped with 65 rice cultivars and four wild relatives of cultivated rice. The results obtained explain the potential importance of two of the amino acid residues for starch association of rice SSIIa. An analysis of the chain-length distribution of β-limit dextrin of amylopectin showed that without SSIIa activity, the relative number of A-chains (the short chains without branches) increased and that of B1-chains (the short chains with branches) decreased. This suggests that, given the SSIIa defect, short A-chains could not reach a sufficient length for branching enzymes to act on them to produce B1-chains.

scholarly journals Production of very-high-amylose cassava by post-transcriptional silencing of branching enzyme genes

2018 ◽  
Author(s):  
Wenzhi Zhou ◽  
Shanshan Zhao ◽  
Shutao He ◽  
Qiuxiang Ma ◽  
Xinlu Lu ◽  
...  
Keyword(s):  
Amylose Content ◽  
Length Distribution ◽  
Constitutive Expression ◽  
Raw Material ◽  
Distribution Analysis ◽  
Starch Granules ◽  
Storage Roots ◽  
Chain Length Distribution ◽  
Transgenic Cassava ◽  
High Amylose

AbstractHigh amylose starch, a desired raw material in the starch industry, can be produced by plants deficient in the function of branching enzymes (BEs). Here we report the production of transgenic cassava plants with starches containing up to 50% amylose due to the constitutive expression of hair-pin dsRNAs targeting the BE1 or BE2 genes. A significant decrease in BE transcripts was confirmed in these transgenic plants by quantitative real-time RT-PCR. The absence of BE1 protein in the BE1-RNAi plant lines (BE1i) and a dramatically lower level of BE2 protein in the BE2-RNAi plant lines (BE2i) were further confirmed by Western blot assays. All transgenic plant lines were grown up in the field, but with reduced biomass production of the above-ground parts and storage roots compared to wild type (WT). Considerably high amylose content in the storage roots of BE2i plant lines was achieved, though not in BE1i plant lines. Storage starch granules of BE1i and BE2i plants had similar morphology as WT, however, the size of BE1i starch granules were bigger than that of WT. Comparisons of amylograms and thermograms of all three sources of storage starches revealed dramatic changes to the pasting properties and a higher melting temperature for BE2i starches. Glucan chain length distribution analysis showed a slight increase in chains of DP>36 in BE1i lines and a dramatic increase in glucan chains between DP 10-20 and DP>40 in BE2i lines, compared to that of WT starch. Furthermore, BE2i starches displayed a B-type X-ray diffraction pattern instead of the A-type pattern found in BE1i and WT starches. Therefore, cassava BE1 and BE2 function differently in storage root starch biosynthesis; silencing of cassava BE1 or BE2 caused various changes to starch physico-chemical properties and amylopectin structure. We also report that remarkably high amylose content in cassava starch has been first obtained in transgenic cassava by silencing of BE2 expression, thus showing a high potential for future industrial utilization.

scholarly journals Glycemic index studies in rice (Oryza sativa L.) varieties developed by ANGRAU

2021 ◽  
Vol 17 (AAEBSSD) ◽  
pp. 133-137
Author(s):  
S. Divya Prasanna Kumari ◽  
G. Nirmala Devi ◽  
N. Chamundeswari
Keyword(s):  
Glycemic Index ◽  
Significant Variation ◽  
Agricultural Research ◽  
Amylose Content ◽  
Oryza Sativa L ◽  
Research Station ◽  
Rice Varieties ◽  
Gel Consistency ◽  
The Mean ◽  
Chemical Traits

Twenty popular rice varieties developed by ANGRAU obtained from Regional Agricultural Research Station (RARS), Maruteru during Kharif – 2019, were screened for chemical quality traits viz., gel consistency, gelatinization temperature, amylose along with glycemic index.In our study, significant variation was observed among all the varieties for chemical traits but no significant variation was observed in case of glycemic index.The amylose content observed over the varieties ranged from 21.7 per cent to 24.73 per cent. All the varieties have intermediate amylose content. Gel consistency ranged from 37.67 (hard gel) to 75 (soft gel) with the mean of 52.57. The alkali spreading value was noticed to be low, intermediate and high among all rice varieties.Glycemic index rangedfrom 56.72 -66.43 with a general mean of 60.67. Furthermore, all the varieties were categorized as medium GI varieties (56-69). Among all the varieties, Pushyami has shown the least value (56.72) for glycemic index.From the present investigation, it is concluded that, Rice varieties such as Chandra, Indra, Sri Dhruthi, Swarna, Samba Mahsuri, Sujatha, Maruteru Samba, MaruteruMahsuri recorded intermediate amylose, alkali spreading value and medium GI, which are desirable for rice consumers while counting for better rice with the best quality and glycemic index.

scholarly journals A comparative study on chemical and cooking properties of abiotic stress tolerant and other high yielding rice varieties in Bangladesh

2018 ◽  
Vol 42 (4) ◽  
pp. 673-679
Author(s):  
A Matin ◽  
MA Siddiquee ◽  
S Akther ◽  
MK Alam ◽  
MS Ali
Keyword(s):  
Abiotic Stress ◽  
Comparative Study ◽  
Normal Condition ◽  
Amylose Content ◽  
Cooking Time ◽  
Elongation Ratio ◽  
Rice Varieties ◽  
Cooking Properties

The experiment was conducted to know the chemical and cooking properties of nineteen BRRI released high yielding rice varieties (HYVs) including salinity, drought and submergence tolerant varieties. All the rice varities were grown in normal condition. Among the HYVs, amylose content of the varieties range from 19 to 27.0% and BRRI dhan47 contained the highest amylose content (27%). The highest amount of protein (9.3%) was found in BRRI dhan56 followed by BRRI dhan42 (9%) and BRRI dhan43 (8.8%). Alkali spreading value ranged from 3.0 to 7.0. Maximum cooking time (20.5 min.) was required in the variety of BRRI dhan40. Alkali spreading value was found significantly and negatively correlated with cooking time. The kernel elongation ratio was greater than 1.1 in all the varieties except BRRI dhan62. The imbibition ratio was greater than 3.0 in all the varieties except BRRI dhan43 and BRRI dhan61. There were no significant differences between non-abiotic and abiotic stress tolerant varities in respect of chemical and cooking properties because all varities were grown in normal condition.Bangladesh J. Agril. Res. 42(4): 673-679, December 2017

scholarly journals Analysis of Genetic Potential of Banyuwangi Local Rice (Oryza sativa L.) Based on Relative Expression of Homogentisate Geranylgeranyl Transferase (HGGT) and Granule-Bound Starch Synthase I (GBSSI) Gene

2021 ◽  
Vol 28 (2) ◽  
pp. 181
Author(s):  
Dyati Galuh Pratita ◽  
Tita Putri Milasari ◽  
Elhah Nailul Khasna ◽  
Sunarmi Sunarmi ◽  
Evi Susanti ◽  
...  
Keyword(s):  
Glycemic Index ◽  
Amylose Content ◽  
Oryza Sativa L ◽  
Rice Varieties ◽  
Relative Expression ◽  
Qrt Pcr ◽  
Genetic Potential ◽  
Geranylgeranyl Transferase ◽  
High Amylose ◽  
Low Glycemic Index

Rice nutrition including vitamin and amylose contents become important aspect for many people around the world. Rice with high amylose content (low glycemic index) is good for those with Diabetes mellitus. Tocotrienol, one precursor of Vitamin-E biosynthesis is catalyzed by enzymes encoded HGGT, while amylose biosynthesis is catalyzed by enzymes encoded GBSSI. The objective of this study was to find rice varieties with high tocotrienol and/or amylose content based on the expression of HGGT and GBSSI among eight Banyuwangi local rice varieties. Relative expression of HGGT and GBSSI was measured by qRT-PCR and analyzed using 2ΔCt method. Statistical analysis resulted in the significantly different of HGGT and GBSSI relative expression among samples. Relative expression of HGGT from the highest to the lowest were demonstrated by Hitam Melik, Hitam Pekat, Blambangan A3, Merah Bali, Blambangan A2, Berlian, Janur Kuning, and SOJ A3, respectively; while relative expression of GBSSI from the highest to the lowest were demonstrated by Hitam Melik, Hitam Pekat, SOJ A3, Janur Kuning, Berlian, Merah Bali, Blambangan A3, and Blambangan A2, respectively. Based on this research we conclude that Hitam Melik potentially produces higher tocotrienol and lower glycemic index than other studied varieties.

Networks Having Multimodal Chain-Length Distributions

1997 ◽  
Author(s):  
Burak Erman ◽  
James E. Mark
Keyword(s):  
Free Radical ◽  
Chain Length ◽  
Length Distribution ◽  
Bimodal Distribution ◽  
High Energy ◽  
Chain Length Distribution ◽  
Network Chain ◽  
Ultimate Properties ◽  
Non Gaussian ◽  
Chain Lengths

As was mentioned in chapter 10, end-linking reactions can be used to make networks of known structures, including those having unusual chain-length distributions. One of the uses of networks having a bimodal distribution is to clarify the dependence of ultimate properties on non-Gaussian effects arising from limited-chain extensibility, as was already pointed out. The following chapter provides more detail on this application, and others. In fact, the effect of network chain-length distribution, is one aspect of rubberlike elasticity that has not been studied very much until recently, because of two primary reasons. On the experimental side, the cross-linking techniques traditionally used to prepare the network structures required for rubberlike elasticity have been random, uncontrolled processes, as was mentioned in chapter 10. Examples are vulcanization (addition of sulfur), peroxide thermolysis (free-radical couplings), and high-energy radiation (free-radical and ionic reactions). All of these techniques are random in the sense that the number of cross-links thus introduced is not known directly, and two units close together in space are joined irrespective of their locations along the chain trajectories. The resulting network chain-length distribution is unimodal and probably very broad. On the theoretical side, it has turned out to be convenient, and even necessary, to assume a distribution of chain lengths that is not only unimodal, but monodisperse! There are a number of reasons for developing techniques to determine or, even better, control network chain-length distributions. One is to check the “weakest link” theory for elastomer rupture, which states that a typical elastomeric network consists of chains with a broad distribution of lengths, and that the shortest of these chains are the “culprits” in causing rupture. This is attributed to the very limited extensibility associated with their shortness that is thought to cause them to break at relatively small deformations and then act as rupture nuclei. Another reason is to determine whether control of chain-length distribution can be used to maximize the ultimate properties of an elastomer. As was described in chapter 10, a variety of model networks can be prepared using the new synthetic techniques that closely control the placements of crosslinks in a network structure.

Chain-Length Distribution Functions during Polymerization

1954 ◽  
Vol 27 (3) ◽  
pp. 622-628 ◽  
Author(s):  
W. F. Watson
Keyword(s):  
Reaction Mechanism ◽  
Chain Length ◽  
Length Distribution ◽  
Kinetic Scheme ◽  
Distribution Functions ◽  
Average Chain Length ◽  
Chain Length Distribution ◽  
Molecular Weights ◽  
Measurable Rate ◽  
Chain Lengths

Abstract Functions for the distribution of chain lengths of a polymer formed during polymerization have been evaluated in terms of the directly measurable rate and rate of initiation, or the single equivalent measurement of number-average chain length. No details of the reaction mechanism are required, except for the occurrence of termination by combination of polymer radicals. This is in contrast to the usual derivation of distribution functions from the postulated kinetic scheme. The three types of termination are considered, (1) combination absent, (2) combination predominant, and (3) a mixture of combination with other modes of termination. The application to copolymerization is outlined. Relationships between the various average molecular weights are considered.

Single-nucleotide polymorphisms in rice starch synthase IIa that alter starch gelatinisation and starch association of the enzyme

2005 ◽  
Vol 32 (9) ◽  
pp. 763 ◽  
Author(s):  
Takayuki Umemoto ◽  
Noriaki Aoki
Keyword(s):  
Amino Acid ◽  
Single Nucleotide Polymorphisms ◽  
Oryza Sativa L ◽  
Length Distribution ◽  
Branch Length ◽  
Starch Synthase ◽  
Rice Starch ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Chain Length Distribution

The starch synthase IIa (SSIIa) gene of rice (Oryza sativa L.) has been shown to be the alk gene that controls alkali disintegration of rice grains, although the effects of naturally occurring alk mutant alleles on enzyme function have yet to be determined. We genotyped 60 rice cultivars for two single-nucleotide polymorphisms (SNPs) in rice SSIIa, including one that results in an amino acid substitution. Incorporating data for three other SNPs previously genotyped in rice SSIIa, five haplotypes were found. We analysed the association of these SSIIa haplotypes with the chain-length distribution of amylopectin, the gelatinisation temperature of rice flour, the alkali spreading score, and the starch association of the enzyme. It was determined that two SNPs resulting in amino acid changes close to the C-terminus most likely alter SSIIa both in terms of activity and starch granule association. This in turn alters the branch-length distribution of amylopectin and the gelatinisation properties of starch.

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