Preparation and Properties of Regenerated Cellulose/Amylopectin Blend Fibers from 1-Butyl-3-Methylimidazolium Chloride with Controlled Biodegradation

Regenerated cellulose/amylopectin blend fibers with controlled biodegradation were produced using dry-jet wet-spinning technology from cellulose/amylopectin/1-butyl-3-methylimidazolium chloride blends.Morphological,structural and chemical analyses revealed that dense,homogeneous and void-free blend fibers were prepared in a two-stage dissolution process.The blend fibers were regenerated from water and treated with water or 95%(volume fraction)ethanol.However,cellulose-amylopectin interactions caused crystalline rearrangements in the blend fibers,resulting in a general decrease in crystallinity.Generally,tensile properties decreased with increasing amylopectin content,except that the blend fibers with 10%(mass fraction)amylopectin exhibited higher tensile strength than the regenerated cellulose control fibers.Ethanol treatment reduced the hydrophilicity of the blend fibers,increasing the crystallinity of the blend fibers.The blend fibers exhibited remarkable degradation,directly proportional to the amylopectin content.Despite higher crystallinity,ethanol-treated blend fibers degraded faster than water-treated fibers,indicating amylopectin and ethanol regulated the degradation.

Effect of Fast Neutron Irradiation on Amylose Content and Amylopectin Structure of Thailand Rice Cultivar Jao Hom Nin

[Objective]The aim was to research the effect of fast neutron irradiation on amylose content and amylopectin structure.[Method] The amylose content and amylopectin structure of the M4 plants of Thailand rice cultivar Jao Hom Nin irradiated with fast neutron at 13 Gy were evaluated and analyzed in this paper.[Result]The results showed that amylose content of rice could be changed by fast neutron irradiation,many rice mutants with reduced amylose content and many others with enhanced amylose content even some mutants with amylose content near to waxy rice could be isolated,but fast neutron irradiation almost had no effect on amylopectin structure of the samples.[Conclusion]The study provided a basis for breeding rice cultivar with different amylose content in order to meet with the taste hobby of different people and the further processing of diverse rice products via the irradiation of fast neutron.

Characterization of eating quality and starch properties of two Wx alleles japonica rice cultivars under different nitrogen treatments

To understand the effect of nitrogen(N) fertilizer on rice(Oryza sativa L.) eating and cooking quality(ECQ). Here, we investigated the ECQ attributes, physicochemical foundation of ECQ, and amylopectin fine structure of two Waxy(Wx) alleles japonica rice cultivars Nanjing 9108(NJ9108) and Huaidao 5(HD5) under four N rates(0, 150, 300, and 450 kg ha^-1). Sensory and pasting properties of the two cultivars varied depending on N rates. Compared with the control(0 kg ha^-1), the overall eating quality and sensory value were significantly decreased under the N rates of 300 and 450 kg ha^-1. Further, conventional descriptive analysis showed that the stickiness and retrogradation of cooked rice were significantly decreased. These results indicated that application of N fertilizer seems to affect the texture of cooked rice, causing it to be less sticky, lowering its retrogradation, and consequently reducing its palatability. Results from rapid visco analyzer(RVA) revealed that the peak and breakdown viscosities significantly decreased, while the setback viscosity and peak time increased under the N rates of 300 and 450 kg ha^-1. However, no significant difference was observed when the N rate was 150 kg ha^-1, indicating that less N fertilization can maintain rice ECQ. As the N rate increasing, protein content increased, whereas apparent amylose content, starch content, and gel consistency almost unchanged. Interestingly, compared with the control, under N treatments, the percentage of short amylopectin branches in NJ9108 was decreased, but increased in HD5, as controlled by amylopectin synthesis-related genes. Notably, SSI and BEIIb were down-regulated in NJ9108, whereas BEIIb was up-regulated in HD5. Thus, the palatability of both rice cultivars was significantly decreased under excessive N fertilization as a consequence of reduced stickiness and retrogradation of the cooked rice, which might have resulted from an elevated protein content and altered amylopectin fine structure. In addition, amylopectin synthesis appeared to be affected by N fertilizer and the genotype of the rice cultivar.

Amylopectin structure and crystallinity explains variation in digestion kinetics of starches across botanic sources in an in vitro pig model

Background: Starch is the main source of energy in commonly used pig diets.Besides effects related to the extent of starch digestion,also several effects related to variation in digestion rate have recently been demonstrated in non-ruminants.Different rates of starch digestion in animals and in in vitro models have been reported,depending on the botanic origin of starch.Starches from different botanic sources differ widely in structural and molecular properties.Predicting the effect of starch properties on in vitro digestion kinetics based on existing literature is hampered by incomplete characterization of the starches,or by a selective choice of starches from a limited number of botanic sources.This research aimed to analyse the relationships between starch properties and in vitro digestion kinetics of pure starches isolated from a broad range of botanic origins,which are used in non-ruminant diets or have a potential to be used in the future.Therefore we studied starch digestion kinetics of potato,pea,corn,rice,barley,and wheat starches,and analysed the granule diameter,number of pores,type and amount of crystalline structure,amylose content and amylopectin side-chain length of all starches.Results: Multivariate analysis revealed strong correlations among starch properties,leading us to conclude that effects of most starch characteristics are strongly interrelated.Across all analysed botanic sources,crystalline type and amylopectin chain length showed the strongest correlation with in vitro digestion kinetics.Increased percentages of A–type crystalline structure and amylopectin side chains of DP 6–24 both increased the rate of digestion.In addition,within,but not across,(clusters of) botanic sources,a decrease in amylose content and increase in number of pores correlated positively with digestion kinetics.Conclusion: The type of crystalline structure and amylopectin chain length distribution of starch correlate significantly with digestion kinetics of starches across botanic sources in an in vitro pig model.Variation in digestion kinetics across botanic sources is not additively explained by other starch properties measured,but appears to be confined within botanical sources.

Starch Accumulation and Enzyme Activities Associated with Starch Synthesis in Maize Kernels

The filling rate and the starch accumulation in developing maize kernel were analyzed. The changes of enzyme activities associated with sucrose metabolism and starch biosynthesis were investigated. The purpose is to discuss the enzymatic mechanisms responsible for starch synthesis. Two types of maize cultivars （Zea mays）, high starch maize （Feiyu 3） and normal maize （Yuyu 22）, were grown in a corn field. The factors involved in starch synthesis were performed during the growth period. The kernel filling rate, the sucrose content, the starch accumulating rates and the activities of SS （sucrose synthase）, GBSS （granule-bound starch synthase）, SBE （starch branching enzyme） of Feiyu 3, which has high starch content, were significantly higher than those of Yuyu 22, which has low starch content, after 10 DAP （days after pollination）. Correlation analysis indicated that ADPGPPase （ADP-glucose pyrophosphorylase） and DBE （starch debranching enzyme） were not correlated with the starch accumulating rates and the kernel filling rate, but the SS activity at the middle and late period were highly significantly correlated with the starch accumulating rates and the kernel filling rate. The GBSS activity was highly significantly correlated with the amylose accumulating rate, but not correlated with the kernel filling rate. The SBE activity was highly significantly correlated with the amylopectin accumulating rate and the kernel filling rate. It was not ADPGPPase and DBE, but SS was the rate-limiting factor of starch biosynthesis in developing maize kernels. GBSS had an important effect on amylose accumulation, and SBE had a significant effect on amylopectin accumulation.

Effect of high temperature on the expressions of genes encoding starch synthesis enzymes in developing rice endosperms

High temperature is the major environmental factor affecting grain starch properties of cooking rice cultivars. In this study, two non-waxy indica rice genotypes, cv. 9311 and its mutant with extremely high amylose phenotype（9311eha） were used to study the differential expressions of genes in starch synthesis and their responses to high temperature（HT）. Significant increase in apparent amylose content and hot-water-soluble starch content in mutant 9311 eha were genetically caused by a substitution from AGTTATA to AGGTATA at the leader intron 5′ splice site in Wx gene. This mutation resulted in different m RNA transcript levels, m RNA splicing efficiencies and protein levels of Wx between the two rice genotypes, which also lead to the genotype-dependent alteration in the temporal pattern of Wx transcription and granule-bound starch synthase（GBSS） activity in response to HT. However, changes in the activities of other starch synthesizing enzymes and their expressions of distinct isoform genes were not significant with the Wx gene mutation, thus only minor difference in the particle size of starch granule, chain-length distribution and gelatinization enthalpy were found between the two genotypes. The temporal-specific expression of multiple isoform genes responsive to different temperature regiments indicated that the reduction of GBSS transcript expression under HT was generally accompanied by the decreased expressions of SSSIIa, SSSIIIa and SBEIIb. Consequently, high temperature-ripened grains in 9311 eha showed high proportion of intermediate and long B chains and somewhat lower level of short A chain compared to the wildtype. The temperature-dependent alteration of amylose content was not only attributed to the reduced expression of GBSS, but also associated with the complimentary effect of SSSIIa and SBEIIb.

Suppression of starch synthase I(SSI) by RNA interference alters starch biosynthesis and amylopectin chain distribution in rice plants subjected to high temperature

Based on known cDNAs of rice starch synthase isoforms,we constructed dsRNA interference vectors for starch synthase I(SSI)to produce transgenic plants containing starch with a moderately high amylose content.We investigated the effect of SSI suppression on grain quality traits,starch biosynthesis,and amylopectin chain distribution in rice plants exposed to two different temperature regimes.The activities and transcripts of BEs,DBEs,and other SS isoforms were further investigated to clarify the effect of SSI suppression on these key enzymes and their specific isoforms under different temperature treatments.Suppression of SSI by RNAi altered grain starch component and amylopectin chain distribution,but it exerted only a slight effect on total starch content(%)and accumulation amount(mg kernel?1)and on starch granule morphology and particle size distribution.Under normal temperature(NT),insignificant differences in kernel weight,chalky kernel proportion,chalky degree,and starch granule morphology between SSI-RNAi line and its wild type(WT)were observed.However,amylose content(AC)level and granule-bound starch synthase(GBSS)activity in rice endosperms were markedly increased by SSI-RNAi suppression.The chalky kernel proportion and chalky degree of SSIRNAi lines were significantly higher than those of WT under high temperature(HT)exposure at filling stage.Inhibition of SSI by RNAi affected amylopectin chain distribution and raised starch gelatinization temperature(GT)in two ways:directly from the SSI deficiency itself and indirectly by reducing BEIIb amounts in an SSI-deficient background.The deficiency of SSI expression led to an alteration in the susceptibility of grain chalkiness occurrence and starch gelatinization temperature to HT exposure,owing to a pleiotropic effect of SSI deficiency on the expression of other genes associated with starch biosynthesis.

Comparison of selective flocculation of low grade goethitic iron ore fines using natural and synthetic polymers and a graft copolymer

This study aims to beneficiate low grade goethitic iron ore fines using a selective flocculation process. Selective flocculation studies were conducted using different polymers such as starch amylopectin(AP), poly acrylic acid(PAA), and a graft copolymer(AP-g-PAA). The obtained results were analyzed; they indicate the enhancement of the iron ore grade from 58.49% to 67.52% using AP-g-PAA with a recovery of 95.08%. In addition, 64.45% Fe with a recovery of 88.79% was obtained using AP. Similarly, using PAA, the grade increased to 63.46% Fe with a recovery of 82.10%. The findings are also supported by characterizing concentrates using X-ray diffraction(XRD) and electron probe microanalysis(EPMA) techniques.

The Principles of Starch Gelatinization and Retrogradation

The polysaccharides, such as κ-carrageenan, ι-carrageenan, agarose (agar), gellan gum, amylose, curdlan, alginate, and deacetylated rhamsan gum, in water changed into an ice-like structure with hydrogen bonding between polymer and water molecules, and between water-water molecules even at a concentration range of 0.1% - 1.0% (W/V) at room temperature, resulting in gelation. Such dramatic changes from liquid into gels have been understood at the molecular level in principles. In this review, we describe the structure-function relationship of starch on the view point of rheological aspects and discuss gelatinization and retrogradation mechanism including water molecules at molecular level. The starch molecules (amylose and amylopectin) play a dominant role in the center of the tetrahedral cavities occupied by water molecules, and the arrangement is partially similar to a tetrahedral structure in a gelatinization process. The arrangement should lead to a cooperative effect stabilizing extended regions of ice-like water with hydrogen bonding on the surface of the polymer molecules, where hemiacetal oxygen and hydroxyl groups might participate in hydrogen bonding with water molecules. Thus, a more extended ice-like hydrogen bonding within water molecules might be achieved in a retrogradation process. Though many investigations not only include starch gelatinization and retrogradaion, but also the gelling properties of the polysaccharides have been undertaken to elucidate the structure-function relationship, no other researchers have established mechanism at the molecular level. There is reasonable consistency in our investigations.

Effects of dietary amylose to amylopectin ratio on growth performance,carcass quality characteristics and meat fatty acids in Chinese Qinchuan cattle

This study evaluated the effects of the dietary starch amylose/amylopectin ratio on growth performance,rumen fermentation and blood parameters,carcass characteristics and marbling score,and meat fatty acid profiles and transcriptional changes in the genes involved in the gluconeogenesis pathway in Chinese Qinchuan cattle.Forty-five cattle were randomly divided into three groups.The bulls were fed a control diet(middle amylose/amylopectin ratio=0.47)or diets with either waxy corn starch(WS)inclusion(low amylose/amylopectin ratio=0.23)or pea starch(PS)inclusion(high amylose/amylopectin ratio=0.60)for 90 days.The bulls were individually allowed to receive the diets at the daily amount of at least 2.1%of their individual BW twice daily.The bulls were weighed at 45-day intervals,and blood and rumen fluid samples were also collected at 45-day intervals.The bulls were slaughtered and longissimus thoracis(LT)samples were collected for meat quality measurements.Compared with PS,the average daily gain(ADG)and feed efficiency in control and WS were increased(P<0.05)during d 0 to 45.However,the feed efficiency in PS was increased(P<0.05)compared with the control and WS during d 46 to 90.During the whole feeding trial,the ADG in control and WS showed trends that were higher(0.05<P<0.1)than that of PS,while other growth performance measures and feed intake did not differ(P>0.05)among the three groups.Compared with PS,the serum insulin concentration in WS was increased(P<0.05)at d 45,but not at d 90.Compared with control and WS,the serum SOD and T-AOC concentrations in PS were increased(P<0.05)at d 45,but not at d 90.Compared with control,the rumen microbial crude protein contents in WS and PS were increased(P<0.05)at d 0,while those of control and WS were higher(P<0.05)than that of PS at d 45,but not at d 90.Compared with PS,the backfat thickness in control and WS were increased(P<0.05),however,the marbling score and expression of genes related to the gluconeogenesis pathway in liver of the three groups did not differ(P>0.05).Chemical and physio-chemical compositions of LT did not differ(P>0.05)among the three groups.In conclusion,diets with low or middle amylose/amylopectin ratios increased the backfat thickness,and tended to improve ADG,but had no effect on other carcass characteristics,fat content in the LT,or the expression of hepatic genes related to the gluconeogenesis pathway in Chinese Qinchuan cattle.

Effects of different starch structures on energy metabolism in pigs

Background Starch is a major component of carbohydrates and a major energy source for monogastric animals.Starch is composed of amylose and amylopectin and has different physiological functions due to its different structure.It has been shown that the energy supply efficiency of amylose is lower than that of amylopectin.However,there are few studies on the effect of starch structure on the available energy of pigs.The purpose of this study was to measure the effect of different structures of starch in the diet on the net energy(NE)of pigs using a comparative slaughter method and to establish a prediction equation to estimate the NE of starch with different structures.Fifty-six barrows(initial BW 10.18±0.11 kg)were used,and they were housed and fed individually.Pigs were divided into 7 treatments,with 8 replicates for each treatment and 1 pig for each replicate.One of the treatments was randomly selected as the initial slaughter group(ISG).Pigs in the remaining treatments were assigned to 6 diets,fed with basic diet and semi-pure diets with amylose/amylopectin ratio(AR)of 3.09,1.47,0.25,0.15 and 0.12,respectively.The experiment lasted for 28 d.Results Results showed that compared with the high amylose(AM)groups(AR 3.09 and 1.47),the high amylopectin(AP)group(AR 0.15)significantly increased the final BW,average daily weight gain and average daily feed intake of pigs(P<0.05),but the F:G of the AM group was lower(P<0.01).In addition,AR 0.15 and 0.12 groups have higher(P<0.01)nutrient digestibility of dry matter,crude protein,gross energy and crude ash.Meanwhile,compared with other groups,AR 0.15 group has a higher(P<0.05)NE intake and energy retention(RE).The regressive equation for predicting with starch structures was established as RE=1,235.243-48.298AM/AP(R^(2)=0.657,P=0.05).Conclusions In conclusion,NE intake and RE of pigs augmented with the increase of dietary amylopectin content,indicating that diets high in amylopectin were more conducive to promoting the growth of pigs in the late conserva-tion period.

Activities of the Enzymes Involved in Starch Synthesis and Starch Accumulation in the Grains of Wheat Cultivars, GC8901 and SN1391

Two wheat cultivars, GC8901 (hard winter wheat) and SN1391 (soft winter wheat), were used for investigating the changes of enzyme activities for sucrose metabolism and starch biosynthesis and the accumulation character of starch composition. The result showed that activities of sucrose (SS), sucrose-phosphate synthase (SPS), adenosine diphosphorate glucose pyrophrylase (AGPase) and soluble starch syntheses (SSS) of 1391, which have more starch, were significant higher than those of 8901, that with low starch content. But the changing of granule-bound starch synthase (GBSS) activity was consistent with the amylose content, which indicated that amylose contents in grain were determined by GBSS activity, especially the activity at later grain filling stages. Simulating with Richards equation showed that it was initiating time and accumulation rate, but not accumulation duration that determined the content of starch composition. Furthermore, changing of sucrose transport capacity was consistent with SSS and GBSS activities, starch accumulation rate was accordant to AGPase and SS/SPS ration, not SS, SPS, SSS or GBSS activities. The results suggested that there was no inevitable relation of starch accumulating rate and starch composition contents with the activity of single enzyme such as SS, SPS, SSS or GBSS, but closely related to AGPase activity and SS/SPS ratio, and it was SPS and AGPase that play a vital role in the biosynthetic pathway. Later polymerization reactions catalyzed by SSS and GBSS don’t seem to control the rate of starch accumulation, but do affect starch structure.

Amylopectin from Glutinous Rice as a Sustainable Binder for High-Performance Silicon Anodes

Silicon(Si)has been investigated as a promising anode material because of its high theoretical capacity(4200 m Ah g^(-1)).However,silicon anode suffers from huge volume changes during repeated charge–discharge cycles.In this work,inspired by a remarkable success of the glutinous rice mortar in the Great Wall with ca.2000-year history,amylopectin(AP),the key ingredient responsible for the strong bonding force,is extracted from glutinous rice and utilized as a flexible,aqueous,and resilient binder to address the most challenging drastic volume-expansion and pulverization issues of silicon anode.Additionally,the removal of toxic N-methyl-2-pyrrolidone(NMP)organic solvent makes the electrode fabrication process environmentally friendly and healthy.The as-prepared Si-AP electrode with 60 wt%of Si can uphold a high discharge capacity of 1517.9 m Ah g^(-1)at a rate of 0.1 C after 100 cycles.The cycling stability of the Si-AP has been remarkably improved in comparison with both traditional polyvinylidene fluoride(PVDF)and aqueous carboxymethylcellulose(CMC)binders.Moreover,when the content of silicon in the Si-AP electrode increases to 70 wt%,a high discharge capacity of 1463.1 m Ah g^(-1)can still be obtained after 50 cycles at 0.1°C.These preliminary results suggest that the sustainably available and environmentally benign amylopectin binders could be a promising choice for the construction of highly stable silicon anodes.

Nutrient Composition of Different Foxtail Millet Seeds

Ten millet cultivars from China and abroad were analyzed for their crude fat, amylose and amylopectin, crude protein and amino acid content. A wide variation was observed in amylopectin contain, ranging from 54.47% to 69.26%, while amylose content ranged from 11.26% to 23.22%. The average crude fat in all cultivates was 3.46%, and most cultivates ranged from 3.1% to 3.7%. Protein contents ranged from 8.61% to 15.54% with a mean value of 11.94%. For amino acid composition, the ten cultivates were particularly rich in leucine, and the mean was 34.57 mg/g. The millet cultivars were also high in glycine, glutamic acid and cysteine. Millet was known to be limiting in the essential amino lysine, and the mean was 5.18 mg/g. Other amino acids, tyrosine, histidine and arginine were also very low in the ten cultivars. In general, significant nutrient composition differences were observed between the different millet cultivars, and A2 （a kind of mother line of the hybrid millet） and hybrid millet registered a higher level of protein and amino acid composition which would be useful in millet breeding.

Influence of Phase Behavior and Miscibility on Mechanical, Thermal and Micro-Structure of Soluble Starch-Gelatin Thermoplastic Biodegradable Blend Films

Polymer blends of cold water soluble starches (amylose or amylopectin soluble starch) with gelatin were prepared using solvent casting method. The solid state miscibility and polymer-polymer interactions between the constituent polymers were studied by fourier transforms infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorirmetry (DSC), light optical microscopy (OP) and scanning electron microscopy (SEM), whereas the thermal stability of the blends was studied by thermogravimetric analysis (TGA). Furthermore, tensile and water vapor barrier properties of the blends were assessed. The obtained results exhibited that gelatin was more miscible with amylose soluble starch than with amylopectin soluble starch. Moreover, enhancing mechanical and water barrier properties of amylose soluble starch/gelatin blends were more pronounced than those of amylopectin soluble starch/gelatin blends. Generally, tensile strength (TS) and Elongation percentage (E) of the blend films were found to be gradually increased with increasing the proportion of gelatin. Nevertheless, increasing starch proportion was in favor of decreasing water vapor permeability (WVP). At equal proportions of starch and gelatin (1:1), TS was raised up to 8.69 MPa for amylose soluble starch/gelatin blend films while it raised up to 4.96 MPa for amylopectin soluble starch/gelatin blend films, and so on E was increased to its maximum by ~179.6% for soluble amylose starch/gelatin blends while it was increased to ~114.5% for amylopectin soluble starch/gelatin blends. On the other hand, WVP was significantly decreased to be 6.46 and 12.09 g·mm/m2·day·kPa for blends of amylose and amylopectin soluble?starches, respectively.

Study on Compositions of Grain Starch and SGP-1 Protein in Black Grain Wheat

In view of the lack of wheat genetic resources with high amylose and high resistant starch contents in the present world,the grain starch components and SGP-1 (SGP-A1,SGP-B1 and SGP-D1) protein composition of 43 black-kernel wheat genetic resources such as Jizi 439 were identified by SDS-PAGE electrophoresis detection.The results showed that 11 materials were lack of SGP-A1,and no materials had SGP-B1 and SGP-D1 deletion.Seven materials were identified to have an amylose content more than 30% of the total starch.A total of 12 materials were selected for the determination of resistant starch content,and five materials were found to have a high resistant starch content.The above results lay a foundation for wheat breeding for high resistant starch content.

Characterization of Starch Granules Affected by Processing in Some Cereal Foods

To understand how baking processes influence starch quality, twelve samples of cereal foods products have been studied. Damaged starch determined by a-amylase hydrolysis to characterize and quantify the molecular composition of cereal foods starches treated with different conditions during processing that had been physically damaged to different extents, by preparation and processing provide the physicochemical data to understand more fully the effects of mechanical damage on amylase, amylopectin content and differential scanning calorimetric （DSC） for selected cereal foods products. There were significant difference between treatments in term of damaged starch content of cereal foods flours which were 0.64% to 36.40%, while the DSC results for the starches were the gelatinisation onset （To）, peak temperature （Tp） and conclusion temperature （To）, and temperatures of selected food starches ranged from 34.86 ℃ to 75.20 ℃, 54.04 ℃ to 85.94 ℃, and 63.5 ℃ to 95.16 ℃. There were significant differences between all cereal foods starches in term of amylose and its contents ranged from 70.3% to 87% and also there were significant differences between the amylopectin content of cereal foods flours ranged from 13.3% to 29.6%.

Optical Sum Frequency Generation Image of Rice Grains

We observed optical sum frequency generation (SFG) images of cross-sections of glutinous rice grains, in order to test a possibility of the SFG microscopy as a tool for monitoring polysaccharide species in rice grains. The SFG response in the CH vibration range was the most intense in the crush cell layer at the edge of the endosperm adjacent to the embryo probably due to optical reflection and scattering effectby the rugged dielectric structure of the crush cell layer. The SFG spectra as a function of the infrared wavelength depended on the measurement position in the endosperm. The SFG results were compared with those by Raman and infrared spectroscopies for the same samples.

Hydrogen Bonds Sites of Amylose or Amylopectin from Starch at the ONION Level (B3LYP/6-311++G [d, p]: AM1)

The research aims to help reduce the enormous post-harvest losses of rice or bananas in Cote d’Ivoire. It focuses on the breakdown mechanism of their starch. This process contributes to their decay. This study wants to elucidate it;to do this, it analyzes the tetra or penta saccharide reactions with the water or dioxide carbon. It calculates the geometric, energetic and spectroscopic parameters at the ONIOM level (B3LYP/6-311++G [d, p]: AM1). These quantities allow establishing that oxygen <img src="Edit_7761c26d-f67d-4826-ab0e-8bff55d6faa3.png" alt="" /> represents the privileged hydrogen bond (HB) site for amylose with four or five D-glucose building blocks. They suggest <img src="Edit_ecd55400-653e-43d0-986d-9814259ebda7.png" alt="" /> and <img src="Edit_048b683f-5690-4078-b8ad-88fa25c5875c.png" alt="" /> are respectively those of amylopectin when the latter consists of four and five D-glucose synthons. They prove that amylose deteriorates before it;the degradation of starch begins with its alteration into disaccharides. It continues with that of amylopectin into tri or tetra-saccharides with four or five building blocks.

Mechanism of Degradation of Rice Starch Amylopectin by Oryzenin Using ONIOM Quantum Calculations [DFT/B3LYP/6-31+G(D, P): AM1]

Understanding the molecular factors of rice degradation during its aging concerns our research team. This article emphasizes oryzenin-amylopectin. It aims to reveal the mechanism of amylopectin deterioration during rice aging. The research exploits the Natural Bond Analysis and ONION method at theory level DFT/B3LYP/6-31+G(d, p) and AM1. This methodological approach allows highlighting amylopectin transformation;oryzenin converts amylopectin into amyloidosis in continuous. This led to monosaccharides and disaccharides.