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Food Chemistry: X Mar 2024Resistant starch (RS) is the total amount of starch that is incompletely or not digested and absorbed in the small intestine. It plays a role similar to dietary fibre...
Resistant starch (RS) is the total amount of starch that is incompletely or not digested and absorbed in the small intestine. It plays a role similar to dietary fibre with beneficial effects for human health. In this study, the RS content of 129 wheat accessions was determined, and the relationship between the several starch physical properties and resistant starch content were analyzed. By comparing the total starch content, amylose starch content, starch chain length distribution, starch crystallization type, starch branching degree, and starch granule morphology between the high RS and low RS content wheat accessions, it was found that the amylose content and RS content were significantly positively correlated. However, in the range of chain length fb 3 (DP ≥ 37), there was a significant negative correlation between amylopectin content and RS content. The surface of starch granules became increasingly smooth as the content of RS increased.
PubMed: 38268838
DOI: 10.1016/j.fochx.2023.101103 -
Plant Biotechnology Journal Jun 2024Head rice yield (HRY) measures rice milling quality and determines final grain yield and commercial value. Here, we report that two major quantitative trait loci for...
Head rice yield (HRY) measures rice milling quality and determines final grain yield and commercial value. Here, we report that two major quantitative trait loci for milling quality in rice, qMq-1 and qMq-2, represent allelic variants of Waxy/Waxy (hereafter Wx) encoding Granule-Bound Starch Synthase I (GBSSI) and Alkali Spreading Value ALK/ALK encoding Soluble Starch Synthase IIa (SSIIa), respectively. Complementation and overexpression transgenic lines in indica and japonica backgrounds confirmed that Wx and ALK coordinately regulate HRY by affecting amylose content, the number of amylopectin branches, amyloplast size, and thus grain filling and hardness. The transcription factor OsDOF18 acts upstream of Wx and ALK by activating their transcription. Furthermore, rice accessions with Wx and ALK alleles showed improved HRY over those with Wx and ALK. Our study not only reveals the novel molecular mechanism underlying the formation of HRY but also provides a strategy for breeding rice cultivars with improved HRY.
Topics: Oryza; Alleles; Plant Proteins; Quantitative Trait Loci; Gene Expression Regulation, Plant; Plants, Genetically Modified; Transcription Factors; Starch Synthase
PubMed: 38245899
DOI: 10.1111/pbi.14288 -
Journal of Applied Glycoscience 2023In this study, we investigated the changes in composition, microstructure, and starch molecular structure of shochu koji during preparation. We observed that the...
In this study, we investigated the changes in composition, microstructure, and starch molecular structure of shochu koji during preparation. We observed that the gelatinized and outer part of starch was decomposed in priority during the early and middle preparation stages. The gap between the starch granules increased with the delayed time. Finally, the koji microstructure became spongy. Shochu koji mold produced two α-amylases in different expression manners. Acid-labile α-amylase was produced in the early and middle preparation stages. Acid-stable α-amylase and saccharification power were produced in the middle and late stages. Throughout the koji preparation, reducing sugars content reached approximately 13-20 % of the total sugar content, with glucose representing over 70 % of the reducing sugars. α-Glucan fragments with C chains of degree of polymerization (DP) 4-73 were observed in the early and middle stages (<23 h), indicating the degradation of amylopectin at long B chains. In the latter stage, the amount of C chains of DP 6-30 decreased, while the longer C chains (DP 30<) did not change. These results showed that acid-labile α-amylase, acid-stable α-amylase, and saccharification enzymes including glucoamylase and α-glucosidase work preferentially on the amorphous regions of starch granules, and cooperative action of these enzymes during koji preparation contributes to the formation of the observed microstructure. Our study is the first report on the decomposition schemes of starch and the microstructure forming process in shochu koji.
PubMed: 38239766
DOI: 10.5458/jag.jag.JAG-2023_0006 -
The RING-Type Domain-Containing Protein GNL44 Is Essential for Grain Size and Quality in Rice ( L.).International Journal of Molecular... Jan 2024Grain size in rice ( L.) shapes yield and quality, but the underlying molecular mechanism is not fully understood. We functionally characterized (), encoding a...
Grain size in rice ( L.) shapes yield and quality, but the underlying molecular mechanism is not fully understood. We functionally characterized (), encoding a RING-type protein that localizes to the cytoplasm. The mutant has fewer but enlarged grains compared to the wild type. is mainly expressed in panicles and developing grains. Grain chalkiness was higher in the mutant than in the wild type, short-chain amylopectin content was lower, middle-chain amylopectin content was higher, and appearance quality was worse. The amylose content and gel consistency of were lower, and protein content was higher compared to the wild type. Rapid Visco Analyzer results showed that the texture of cooked rice changed, and that the taste value of was lower, making the eating and cooking quality of worse than that of the wild type. We used , , and monogenic and two-gene near-isogenic lines to study the effects of different combinations of genes affecting grain size on rice quality-related traits. Our results revealed additive effects for these three genes on grain quality. These findings enrich the genetic resources available for rice breeders.
Topics: Oryza; Amylopectin; Amylose; Calcium Carbonate; Cooking; Edible Grain
PubMed: 38203760
DOI: 10.3390/ijms25010589 -
Plants (Basel, Switzerland) Dec 2023Waterlogging is a common abiotic stress in global maize production. Maize flowering stage (from tasseling to silking) is more fragile to environmental stresses, and this...
Waterlogging is a common abiotic stress in global maize production. Maize flowering stage (from tasseling to silking) is more fragile to environmental stresses, and this stage frequently overlapped the plum rain season in the middle and lower reaches of Yangtze river in China and affect the yield and quality of spring-sown maize severely. In the present study, the soil moisture content under control and waterlogging conditions at the flowering stage was controlled by a negative-pressure water supply and controlling pot device in a pot trial in 2014-2015. The grain yield, starch content, and starch structural and functional properties under two soil moisture levels were compared using Suyunuo5 (SYN5) and Yunuo7 (YN7) as materials, which are the control hybrids of National waxy maize hybrid regional trials in Southern China. The results observed that the grain yield was reduced by 29.1% for SYN5 with waterlogging due to the decreased grain weight and numbers, which was significantly higher than that of YN7 (14.7%), indicated that YN7 was more tolerant to waterlogging. The grain starch content in YN7 was decreased by 9.4% when plants suffered waterlogging at the flowering stage, whereas the content in SYN5 was only decreased in 2014 and unaffected in 2015. The size of starch granules and proportion of small-molecule amylopectin with waterlogging at the flowering stage increased in SYN5 and decreased in YN7 in both years. The type of starch crystalline structure was not changed by waterlogging, whereas the relative crystallinity was reduced in SYN5 and increased in YN7. The pasting viscosities were decreased, and the pasting temperature was unaffected by waterlogging in general. The gelatinization enthalpy was unaffected by waterlogging in both hybrids in both years, whereas the retrogradation enthalpy and percentage in both hybrids were reduced by waterlogging in 2014 and unaffected in 2015. Between the two hybrids, YN7 has high pasting viscosities and low retrogradation percentage than SYN5, indicated its advantages on produce starch for more viscous and less retrograde food. In conclusion, waterlogging at the flowering stage reduced the grain yield, restricted starch accumulation, and deteriorated the pasting viscosity of waxy maize. Results provide information for utilization of waxy maize grain in food production.
PubMed: 38202416
DOI: 10.3390/plants13010108 -
BMC Biotechnology Jan 2024Lytic polysaccharide monooxygenases (LPMOs) catalyzing the oxidative cleavage of different types of polysaccharides have potential to be used in various industries....
BACKGROUND
Lytic polysaccharide monooxygenases (LPMOs) catalyzing the oxidative cleavage of different types of polysaccharides have potential to be used in various industries. However, AA13 family LPMOs which specifically catalyze starch substrates have relatively less members than AA9 and AA10 families to limit their application range. Amylase has been used in enzymatic desizing treatment of cotton fabric for semicentury which urgently need for new assistant enzymes to improve reaction efficiency and reduce cost so as to promote their application in the textile industry.
RESULTS
A total of 380 unannotated new genes which probably encode AA13 family LPMOs were discovered by the Hidden Markov model scanning in this study. Ten of them have been successfully heterologous overexpressed. AlLPMO13 with the highest activity has been purified and determined its optimum pH and temperature as pH 5.0 and 50 °C. It also showed various oxidative activities on different substrates (modified corn starch > amylose > amylopectin > corn starch). The results of enzymatic textile desizing application showed that the best combination of amylase (5 g/L), AlLPMO13 (5 mg/L), and HO (3 g/L) made the desizing level and the capillary effects increased by 3 grades and more than 20%, respectively, compared with the results treated by only amylase.
CONCLUSION
The Hidden Markov model constructed basing on 34 AA13 family LPMOs was proved to be a valid bioinformatics tool for discovering novel starch-active LPMOs. The novel enzyme AlLPMO13 has strong development potential in the enzymatic textile industry both concerning on economy and on application effect.
Topics: Humans; Starch; Hydrogen Peroxide; Polysaccharides; Amylases; Computational Biology; Mixed Function Oxygenases; Textiles
PubMed: 38200466
DOI: 10.1186/s12896-023-00826-1 -
Nature Communications Jan 2024Cryptosporidium parvum is an obligate intracellular parasite with a highly reduced mitochondrion that lacks the tricarboxylic acid cycle and the ability to generate...
Cryptosporidium parvum is an obligate intracellular parasite with a highly reduced mitochondrion that lacks the tricarboxylic acid cycle and the ability to generate ATP, making the parasite reliant on glycolysis. Genetic ablation experiments demonstrated that neither of the two putative glucose transporters CpGT1 and CpGT2 were essential for growth. Surprisingly, hexokinase was also dispensable for parasite growth while the downstream enzyme aldolase was required, suggesting the parasite has an alternative way of obtaining phosphorylated hexose. Complementation studies in E. coli support a role for direct transport of glucose-6-phosphate from the host cell by the parasite transporters CpGT1 and CpGT2, thus bypassing a requirement for hexokinase. Additionally, the parasite obtains phosphorylated glucose from amylopectin stores that are released by the action of the essential enzyme glycogen phosphorylase. Collectively, these findings reveal that C. parvum relies on multiple pathways to obtain phosphorylated glucose both for glycolysis and to restore carbohydrate reserves.
Topics: Humans; Cryptosporidium parvum; Glucose; Phosphates; Cryptosporidiosis; Escherichia coli; Hexokinase; Cryptosporidium
PubMed: 38191884
DOI: 10.1038/s41467-024-44696-3 -
Nature Structural & Molecular Biology Feb 2024Resistant starch is a prebiotic accessed by gut bacteria with specialized amylases and starch-binding proteins. The human gut symbiont Ruminococcus bromii expresses Sas6...
Resistant starch is a prebiotic accessed by gut bacteria with specialized amylases and starch-binding proteins. The human gut symbiont Ruminococcus bromii expresses Sas6 (Starch Adherence System member 6), which consists of two starch-specific carbohydrate-binding modules from family 26 (RbCBM26) and family 74 (RbCBM74). Here, we present the crystal structures of Sas6 and of RbCBM74 bound with a double helical dimer of maltodecaose. The RbCBM74 starch-binding groove complements the double helical α-glucan geometry of amylopectin, suggesting that this module selects this feature in starch granules. Isothermal titration calorimetry and native mass spectrometry demonstrate that RbCBM74 recognizes longer single and double helical α-glucans, while RbCBM26 binds short maltooligosaccharides. Bioinformatic analysis supports the conservation of the amylopectin-targeting platform in CBM74s from resistant-starch degrading bacteria. Our results suggest that RbCBM74 and RbCBM26 within Sas6 recognize discrete aspects of the starch granule, providing molecular insight into how this structure is accommodated by gut bacteria.
Topics: Humans; Starch; Glucans; Amylopectin; Ruminococcus; Bacteria
PubMed: 38177679
DOI: 10.1038/s41594-023-01166-6 -
Food Chemistry: X Dec 2023The lack of an efficient approach for quality evaluation of sweet potatoes significantly hinders progress in quality breeding. Therefore, this study aimed to establish a...
The lack of an efficient approach for quality evaluation of sweet potatoes significantly hinders progress in quality breeding. Therefore, this study aimed to establish a near-infrared spectroscopy (NIRS) assay for high-throughput analysis of sweet potato root quality, including total starch, amylose, amylopectin, the ratio of amylopectin to amylose, soluble sugar, crude protein, total flavonoid content, and total phenolic content. A total of 125 representative samples were utilized and a dual-optimized strategy (optimization of sample subset partitioning and variable selection) was applied to NIRS modeling. Eight optimal equations were developed with an excellent coefficient of determination for the calibration () at 0.95-0.99, cross-validation () at 0.93-0.98, external validation () at 0.89-0.96, and the ratio of prediction to deviation (RPD) at 6.33-11.35. Overall, these NIRS models provide a feasible approach for high-throughput analysis of root quality and permit large-scale screening of elite germplasm in future sweet potato breeding.
PubMed: 38144853
DOI: 10.1016/j.fochx.2023.100916 -
Food Chemistry: X Dec 2023Straw return can improve rice eating quality by modifying starch formation from long-term field trials, whereas the relevant mechanisms are still unknown. A long-term...
Straw return can improve rice eating quality by modifying starch formation from long-term field trials, whereas the relevant mechanisms are still unknown. A long-term field experiment, including straw removal (CK), straw burning return (SBR), and straw return (SR) was conducted to investigate the starch structure, physicochemical properties, and cooked rice textures of early- and late-rice. Compared with CK, SBR and SR enhanced relative crystallinity, amylopectin long chains in both rice seasons, and gelatinization temperatures in late rice. Compared to SBR, SR decreased protein content and amylopectin short chains but increased starch branching degree, breakdown, and stickiness, ultimately contributing to improved starch thermal and pasting properties. Meanwhile, SR decreased hardness, cohesiveness, and chewiness, resulting in cooked texture meliorated, which was mainly attributed to amylopectin chain length and starch granule size. The results suggest that SR increased cooked texture of rice by altering starch structural and physicochemical properties.
PubMed: 38144815
DOI: 10.1016/j.fochx.2023.100965