Engineering high amylose and resistant starch in maize by CRISPR/Cas9-mediated editing of starch branching enzymes

To improve the amylose content(AC)and resistant starch content(RSC)of maize kernel starch,we employed the CRISPR/Cas9 system to create mutants of starch branching enzyme I(SBEI)and starch branching enzyme IIb(SBEIIb).A frameshift mutation in SBEI(E1,a nucleotide insertion in exon 6)led to plants with higher RSC(1.07%),lower hundred-kernel weight(HKW,24.71±0.14 g),and lower plant height(PH,218.50±9.42 cm)compared to the wild type(WT).Like the WT,E1 kernel starch had irregular,polygonal shapes with sharp edges.A frameshift mutation in SBEIIb(E2,a four-nucleotide deletion in exon 8)led to higher AC(53.48%)and higher RSC(26.93%)than that for the WT.E2 kernel starch was significantly different from the WT regarding granule morphology,chain length distribution pattern,X-ray diffraction pattern,and thermal characteristics;the starch granules were more irregular in shape and comprised typical B-type crystals.Mutating SBEI and SBEIIb(E12)had a synergistic effect on RSC,HKW,PH,starch properties,and starch biosynthesis-associated gene expression.SBEIIa,SS1,SSIIa,SSIIIa,and SSIIIb were upregulated in E12 endosperm compared to WT endosperm.This study lays the foundation for rapidly improving the starch properties of elite maize lines.

The cytosolic isoform of triosephosphate isomerase,ZmTPI4,is required for kernel development and starch synthesis in maize(Zea mays L.)

Triosephosphate isomerase(TPI)is an enzyme that functions in plant energy production,accumulation,and conversion.To understand its function in maize,we characterized a maize TPI mutant,zmtpi4.In comparison to the wild type,zmtpi4 mutants showed altered ear development,reduced kernel weight and starch content,modified starch granule morphology,and altered amylose and amylopectin content.Protein,ATP,and pyruvate contents were reduced,indicating ZmTPI4 was involved in glycolysis.Although subcellular localization confirmed ZmTPI4 as a cytosolic rather than a plastid isoform of TPI,the zmtpi4 mutant showed reduced leaf size and chlorophyll content.Overexpression of ZmTPI4 in Arabidopsis led to enlarged leaves and increased seed weight,suggesting a positive regulatory role of ZmTPI4 in kernel weight and starch content.We conclude that ZmTPI4 functions in maize kernel development,starch synthesis,glycolysis,and photosynthesis.

Evaluation of the Potential of Araucaria angustifolia Seeds as Source of Oligosaccharides, Resistant Starch and Growth of Probiotic Bacteria

“Pinhão”, the seed of Araucaria angustifolia, is an important food, being part of the eating habits of Indigenous communities. In this study, we evaluated the oligosaccharide content, resistant starch and the growth of probiotic bacteria. GF4 (1-fructofuranosylnystose) was the main fructo-oligosaccharides found, in higher contents compared to other food sources. Maltooligosaccharides (MOS) represented the main part of the oligosaccharides profile of Brazilian pine seeds. In descending order of importance was maltoheptaose (G7), maltohexose (G6) and maltotriose (G3). The starches from the variety Sanct josephi presented the highest amount of resistant starch that could stimulate probiotic strains, mainly B. breve and L. plantarum, and may have a prebiotic effect, potentially promoting health benefits. This study advances the understanding of the chemical composition of the main portion of the “pinhão” enhancing awareness of its potential as a healthy food source, contributing to different uses and indirectly with the species preservation.

qSTA2-2,a novel QTL that contributes to seed starch synthesis in Zea mays L.

The seed storage materials accumulate during seed development,and are essential for seed germination and seedling establishment.Here we employed two bi-parental populations of an F2:3 population developed from a cross of improved 220(I220,small seeds with low starch)and PH4CV(large seeds with high starch),as well as recombinant-inbred lines(RILs)of X178(high starch)and its improved introgression line I178(low starch),to identify the genes that control seed storage materials.We identified a total of 12 QTLs for starch,protein and oil,which explained 3.44-10.79%of the phenotypic variances.Among them,qSTA2-1 identified in F2:3 and qSTA2-2 identified in the RILs partially overlapped at an interval of 7.314-9.554 Mb,and they explained 3.44-10.21%of the starch content variation,so they were selected for further study.Fine mapping of qSTA2-2 with the backcrossed populations of ^(I220)/PH4CV in each generation narrowed it down to a 199.7 kb interval that contains 14 open reading frames(ORFs).Transcriptomic analysis of developing seeds from the near-isogenic lines(NILs)of ^(I220)/PH4CV(BC_(5)F_(2))showed that only 11 ORFs were expressed in 20 days after pollination(DAP)seeds.Five of them were upregulated and six of them were downregulated in NIL^(I220),and the differentially expressed genes(DEGs)between NIL^(I220) and NIL^(PH4CV) were enriched in starch metabolism,hormone signal transduction and glycosaminoglycan degradation.Of the eleven NIL^(I220) differential expressed ORFs,ORF4(Zm00001d002260)and ORF5(Zm00001d002261)carry 75%protein sequence similarity,both encodes an glycolate oxidase,were the possible candidates of qSTA2-2.Further analysis and validation indicated that mutation of the qSTA2-2 locus resulted in the dysfunction of ABA accumulation,the embryo/endosperm ratio and the starch and hormone levels.

Night warming increases wheat yield by improving pre-anthesis plant growth and post-anthesis grain starch biosynthesis

Global climate change is characterized by asymmetric warming,i.e.,greater temperature increases in winter,spring,and nighttime than in summer,autumn,and daytime.Field experiments were conducted using four wheat cultivars,namely‘Yangmai 18’(YM18),‘Sumai 188’(SM188),‘Yannong 19’(YN19),and‘Annong 0711’(AN0711),in the two growing seasons of 2019-2020 and 2020-2021,with passive night warming during different periods in the early growth stage.The treatments were night warming during the tillering-jointing(NW_(T-J)),jointing-booting(NWJ-B),and booting-anthesis(NWB-A)stages,with ambient temperature(NN)as the control.The effects of night warming during different stages on wheat yield formation were investigated by determining the characteristics of dry matter accumulation and translocation,as well as sucrose and starch accumulation in wheat grains.The wheat yields of all four cultivars were significantly higher in NW_(T-J)than in NN in the 2-year experiment.The yield increases of semi-winter cultivars YN19 and AN0711 were greater than those of spring cultivars YM18 and SM188.Treatment NW_(T-J)increased wheat yield mainly by increasing the 1,000-grain weight and the number of fertile spikelets,and it increased dry matter accumulation in various organs of wheat at the anthesis and maturity stages by increasing the growth rate at the vegetative growth stage.The flag leaf and spike showed the largest increases in dry matter accumulation.NW_(T-J)also increased the grain sucrose and starch contents in the early and middle grain-filling stages,promoting yield formation.Overall,night warming between the tillering and jointing stages increased the pre-anthesis growth rate,and thus,wheat dry matter production,which contributed to an increase in wheat yield.

Enhancing I^(0)/I^(-)Conversion Efficiency by Starch Confinement in Zinc-lodine Battery

The redox couple of I^(0)/I^(-)in aqueous rechargeable iodine–zinc(I^(2)-Zn)batteries is a promising energy storage resource since it is safe and cost-effective,and provides steady output voltage.However,the cycle life and efficiency of these batteries remain unsatisfactory due to the uncontrolled shuttling of polyiodide(I_(3)^(-)and I_(5)^(-))and side reactions on the Zn anode.Starch is a very low-cost and widely sourced food used daily around the world.“Starch turns blue when it encounters iodine”is a classic chemical reaction,which results from the unique structure of the helix starch molecule–iodine complex.Inspired by this,we employ starch to confine the shuttling of polyiodide,and thus,the I^(0)/I^(-)conversion efficiency of an I^(2)-Zn battery is clearly enhanced.According to the detailed characterizations and theoretical DFT calculation results,the enhancement of I^(0)/I^(-)conversion efficiency is mainly originated from the strong bonding between the charged products of I_(3)^(-)and I_(5)^(-)and the rich hydroxyl groups in starch.This work provides inspiration for the rational design of high-performance and low-cost I^(2)-Zn in AZIBs.

Efficacy of Raw Corn Starch in Insulinoma-Related Hypoglycemia:A Promising Supportive Therapy

Objective To investigate the efficacy of raw corn starch(RCS)in clinical management of insulinoma-induced hypoglycemia.Methods We retrospectively collected clinical data of insulinoma patients who received RCS-supplemented diet preoperatively,and analyzed the therapeutic effects of the RCS intervention on blood glucose control,weight change,and its adverse events.Results The study population consisted of 24 cases of insulinoma patients,7 males and 17 females,aged 46.08±14.15 years.Before RCS-supplemented diet,all patients had frequent hypoglycemic episodes(2.51±3.88 times/week),concurrent with neuroglycopenia(in 83.3% of patients)and autonomic manifestations(in 75.0% of patients),with the median fasting blood glucose(FBG)of 2.70(interquartile range[IQR]:2.50-2.90)mmol/L.The patients'weight increased by 0.38(IQR:0.05-0.65)kg per month,with 8(33.3%)cases developing overweight and 7(29.2%)cases developing obesity.All patients maintained the RCS-supplemented diet until they underwent tumor resection(23 cases)and transarterial chemoembolization for liver metastases(1 case).For 19 patients receiving RCS throughout the day,the median FBG within one week of nutritional management was 4.30(IQR:3.30-5.70)mmol/L,which was a significant increase compared to pre-nutritional level[2.25(IQR:1.60-2.90)mmol/L;P<0.001].Of them,10 patients receiving RCS throughout the day for over four weeks had sustained improvement in FBG compared to pre-treatment[3.20(IQR:2.60-3.95)mmol/L vs.2.15(IQR:1.83-2.33)mmol/L;P<0.001].Five patients who received RCS only at night also had a significant increase in FBG within one week of nutritional management[3.50(IQR:2.50-3.65)mmol/L vs.2.20(IQR:1.80-2.60)mmol/L;P<0.001],but only one patient who continued to receive RCS for over four weeks did not have a significant improvement in FBG.No improvement in weight gain was observed upon RCS supplementation.Mild diarrhea(2 cases)and flatulence(1 case)occurred,and were relieved by reduction of RCS dose.Conclusion The RCS-supplemented diet is effective in controlling insulinoma-induced hypoglycemia.

Modulation of starch digestibility using non-thermal processing techniques:A review

Obesity and type 2 diabetes are widespread throughout the world, especially in developed countries. Starch is an important part of human staple food, the modulating of starch digestibility is conducive to reducing postprandial blood glucose levels and alleviating the chronic disease caused by high caloric intake. The digestion properties of starch are correlated with its structural features, including crystallization, amylose/amylopectin ratio, non-starch components, etc. Among the modified methods applied to regulate starch digestibility, non-thermal processing techniques(NTPT) receive extensive attention due to the characteristics of safety, environmental friendliness and high efficiency. The influence and mechanism of NTPT on the digestion properties of starch are discussed in this review, including ultrasounds, high pressure, γ-irradiation, etc. NTPT induces the alternation of morphological and structural characteristics of native starch, changing their sensitivity to enzymes. The effects of NTPT on the digestibility of starch are highly related to the processing parameters and structure characteristics of native starch. The review shows that NTPT is an effective way to modulate the digestion properties of starch and prevent people from suffering from chronic diseases such as obesity and type 2 diabetes.

Optimization Mechanism of Mechanical Properties of Basalt Fiber-Epoxy Resin Composites by Interfacially Enriched Distribution of Nano-Starch Crystals

Fibre reinforced polymer composites have become a new generation of structural materials due to their unique advantages such as high specific strength,designability,good dimensional stability and ease of large-area monolithic forming.However,the problem of interfacial bonding between the resin matrix and the fibres limits the direct use of reinforcing fibres and has become a central difficulty in the development of basalt fibre-epoxy composites.This paper proposes a solution for enhancing the strength of the fibre-resin interface using maize starch nanocrystals,which are highly yield and eco-friendly.Firstly,in this paper,corn starch nanocrystals(SNC)were prepared by hydrolysis,and were deposited on the surface of basalt fibers by electrostatic adsorption.After that,in order to maximize the modification effect of nano-starch crystals on the interface,the basalt fiber-epoxy resin composite samples were prepared by mixing in a pressureless molding method.The test results shown that the addition of basalt fibers alone led to a reduction in the strength of the sample.Deposition of 0.1 wt%SNC on the surface of basalt fibers can make the strength consistent with pure epoxy resin.When the adsorption amount of SNC reached 0.5 wt%,the tensile strength of the samples was 23.7%higher than that of pure epoxy resin.This is due to the formation of ether bond homopolymers between the SNC at the fibre-epoxy interface and the epoxy resin,which distorts the originally smooth interface,leading to increased stress concentration and the development of cracks.This enhances the binding of basalt fibers.The conclusions of this paper can provide an effective,simple,low-cost and non-polluting method of interfacial enhancement modification.

Alkali Tolerance of Concrete Internal Curing Agent Based on Sodium Carboxymethyl Starch

Internal curing agents (ICA) based on super absorbent polymer have poor alkali tolerance and reduce the early strength of concrete.An alkali tolerate internal curing agent (CAA-ICA) was designed and prepared by using sodium carboxymethyl starch (CMS) with high hydrophilicity,acrylic acid (AA) containing anionic carboxylic group and acrylamide (AM) containing non-ionic amide group as the main raw materials.The results show that the ratio of CAA-ICA alkali absorption solution is higher than that existing ICA,which solves the low water absorption ratio of the ICA in alkali environment.The water absorption ratio of CAA-ICA in saturated Ca(OH)_(2) solution is 95.8 g·g^(-1),and the alkali tolerance coefficient is 3.4.The application of CAA-ICA in cement-based materials can increase the internal relative humidity and miniaturize the pore structure.The compressive strength of mortar increases up to 12.95%at 28 d,which provids a solution to overcome the reduction of the early strength.

Starch Orodispersible Film Loaded with Melatonin for Human Supplementation

An innovative pharmaceutical form for administering melatonin,based on starch orodispersiblefilm(ODF),was designed and prepared.The composition of the ODF included starch as the polymer matrix,the active drug melatonin,and a plasticizer.Melatonin,a natural hormone produced by the pineal gland in the brain,can be absorbed by passive diffusion across the mucous membrane,resulting in improved bioavailability when compared to conventional oral administration.This study shows a simple and efficient method for preparing melatonin-loaded orodispersiblefilms with a physically stable and commercially viable matrix,suitable for use in the pharmaceutical industry.Thefilms were prepared by treating the starch with microwave irradiation,followed by plasticization with glycerol,melatonin loading and drying by solvent casting.Mechanical tests showed thefilms’robustness,with a modulus of approximately 97 MPa,indicating good handling properties.Moisture uptake analysis showed fast water absorption,reaching about 150%within 2 min,indicating its fast oral disintegration potential.Disintegration tests in artificial saliva and dissolution studies indicated the release of the drug in min-utes,indicating the potential properties of thefilm for oral drug delivery.To the best of our knowledge,there is no melatonin ODF based on starch described in the literature.

The impact of the novel starch-lipid complexes on the glucolipids metabolism, inflammation, and gut dysbiosis of type 2 diabetes mellitus rats

It has been widely accepted that resistant starch(RS)provides numerous health benefits for human.In this research,we aimed at evaluating the performance of novel starch-lipid complexes,RS5,in comparison with RS2 on physical features,glucolipids metabolism,inflammation,and gut microbiota profiles of type 2 diabetes mellitus(T2DM)rats.The T2DM model was established by streptozotocin injection to the high-fat-sugar fed rats.According to a serial of biochemical analyses,we found that RS5 diets were strongly correlated with enhanced homeostatic model assessment for insulin secretion(HOMA-IS),high-density lipoprotein cholesterol(HDL-C),adiponectin(ADP),insulin action index(IAI),glucagon-like peptide-1(GLP1),and short-chain fatty acids(SCFAs)in T2DM rats whilst negatively associated with the low-density lipoprotein(LDL-C)and inflammatory cytokines,showing the capabilities to ameliorate T2DM symptoms by regulation of glucolipid metabolism,gut metabolites,and inflammation.On the other hand,RS2-enriched supplementations were influential in the mediation of insulin secretion to improve glucose metabolism.The increasing evidence collected herein suggested that intestinal microbiota could mediate glucolipids metabolism and alleviate inflammation after certain microflora nourished by RS.In addition,RS intake made an impact on phosphoinositide 3-kinase/protein kinase B signaling pathway that might contribute to the improvement of glucose metabolism,insulin resistance,and inflammatory responses.

Rice Grains from Slightly Saline Field Exhibited Unchanged Starch Physicochemical Properties but Enhanced Nutritional Values

This study aims to investigate grain quality and nutritional values of rice(Pokkali,a salt-tolerant cultivar;RD73,a new cultivar improved from KDML105 introgressed with Saltol QTL from Pokkali,and KDML105,a moderately salt-susceptible cultivar)grown under non-saline(0.04–0.87 dS/m)and slightly saline(1.08–4.83 dS/m)field conditions.The results revealed that salinity caused significant reduction in grain size but significant increments in reducing sugar and total protein contents in the grains.Nevertheless,the amounts of starch in the grains of KDML105 and Pokkali rice genotypes were unaffected by the stress.The starch granule size distribution was also unaffected by salinity.Interestingly,only starch from Pokkali was significantly diminished in amylose content,from 19.18%to 16.99%.Accordingly,parameters relating to starch gelatinization,retrogradation,and pasting properties of KDML105 and RD73 were unaffected by salinity;only Pokkali showed a significant increase in percentage of retrogradation along with a significant reduction in gelatinization enthalpy.In the saline field,total phenolic content and antioxidant capacity in the grains of all rice cultivars tended to increase,particularly in Pokkali.On average,essential element contents in grains from the saline-treated plants showed a 33%,32%,32%,22%,20%,11%,and 10%increase in total P,N,K,Mg,Zn,Fe,and Ca content,respectively.Interestingly,total Fe content exhibited the greatest percentage of increments in KDML105(187%).Taken together,cultivation of rice in the slightly saline field did not alter its eating and cooking qualities,while enhanced some nutritional properties such as proteins,minerals,and secondary metabolites like phenolic compounds.

Irrigation regimes modulate non-structural carbohydrate remobilization and improve grain filling in rice(Oryza sativa L.)by regulating starch metabolism

Recently developed ‘super’ rice cultivars with greater yield potentials often suffer from the problem of poor grain filling, especially in inferior spikelets. Here, we studied the activities of enzymes related to starch metabolism in rice stems and grains, and the microstructures related to carbohydrate accumulation and transportation to investigate the effects of different water regimes on grain filling. Two ‘super’ rice cultivars were grown under two irrigation regimes of well-watered(WW) and alternate wetting and moderate soil drying(AWMD). Compared with the WW treatment,the activities of ADP glucose pyrophosphorylase(AGPase), starch synthase(StSase) and starch branching enzyme(SBE), and the accumulation of non-structural carbohydrates(NSCs) in the stems before heading were significantly improved, and more starch granules were stored in the stems in the AWMD treatment. After heading, the activities of α-amylase, β-amylase, sucrose phosphate synthase(SPS) and sucrose synthase in the synthetic direction(SSs)were increased in the stems to promote the remobilization of NSCs for grain filling under AWMD. During grain filling, the enzymatic activities of sucrose synthase in the cleavage direction(SSc), AGPase, StSase and SBE in the inferior spikelets were increased, which promoted grain filling, especially for the inferior spikelets under AWMD.However, there were no significant differences in vascular microstructures. The grain yield and grain weight could be improved by 13.1 and 7.5%, respectively, by optimizing of the irrigation regime. We concluded that the low activities of key enzymes in carbon metabolism is the key limitation for the poor grain filling, as opposed to the vascular microstructures, and AWMD can increase the amount of NSC accumulation in the stems before heading, improve the utilization rate of NSCs after heading, and increase the grain filling, especially in the inferior spikelets, by altering the activities of key enzymes in carbon metabolism.

Differential roles of C-3 and C-6 phosphate monoesters in affecting potato starch properties

The effects of starch phosphate monoester content(SPC),namely C-3(C3P)and C-6 phosphate monoesters(C6P),on the starch properties were investigated using four potato starches with varied SPC/C3P/C6P and two nonphosphorylated maize starches with a similar range of amylose content(AC)as controls.The starch property results showed that a higher SPC is associated with lower turbidity,storage and loss modulus after storage,and water solubility,but higher swelling power(SP)and pasting viscosities.These findings suggested that SPC inhibited molecular rearrangement during storage and starch leaching during heating,and enhanced swelling and viscosities due to increased hydration and water uptake caused by the repulsion effect of phosphate groups and a less ordered crystalline structure.Increased SPC also resulted in lower resistant starch(RS)content in a native granular state but higher RS after retrogradation.Pearson correlations further indicated that SPC/C3P/C6P were positively correlated with peak(r^(2)=0.925,0.873 and 0.930,respectively),trough(r^(2)=0.994,0.968 and 0.988,respectively),and final viscosities(r^(2)=0.981,0.968 and 0.971,respectively).Notably,SPC,mainly C3P,exhibited a significantly positive correlation with SP(r^(2)=0.859)and setback viscosity(r^(2)=0.867),whereas SPC,mainly C6P,showed a weak positive correlation with RS after retrogradation(r^(2)=0.746).However,SPC had no significant correlations with water solubility,turbidity and rheology properties,which were more correlated with AC.These findings are helpful for the food industry to select potato starches with desired properties based on their contents of SPC,C3P,or C6P.

Physicochemical and structural properties of starches from non-traditional sources in China

In this study,we isolated starches from non-traditional sources,including quinoa,lentil,arrowhead,gorgon fruit,sorghum,chickpea,proso millet,and purple potato and investigated their morphology,physicochemical,and functional properties.Significant differences in starch particle morphology,swelling power,solubility,syneresis,crystalline pattern,and pasting viscosity were observed among the starches from these nontraditional sources.Further,all these isolated starches had unique properties because of their characteristic distinct granules when seen under scanning electron microscopy(SEM).The amylose content of the isolated starches shown significant difference(P<0.05),and the values ranged between 11.46%and 37.61%.Results demonstrated that the isolated starches contained between 79.82%to 86.56%starch,indicating that the isolated starches had high purity.X-ray diffraction(XRD)patterns of starches isolated from sorghum,proso millet,quinoa,purple potato,and gorgon fruit presented A-type diffraction pattern;while lentil seeds,arrowhead,and chickpea starches presented C-type diffraction pattern.Overall,these results will promote the development of products based on starch isolated from non-traditional starches.

Preparation and Characterization of Thermoplastic Starch from Sugar Palm (Arenga pinnata) by Extrusion Method

Sugar palm(Arenga pinnata)starch is considered an important renewable,biodegradable,and eco-friendly polymer,which is derived from agricultural by-products and residues,with great potential for the development of biocomposite materials.This research was aimed at investigating the development of TPS biocomposites from A.pinnata palm starch using an extrusion process.Palm starch,glycerol,and stearic acid were extruded in a twin-screw extruder.Scanning electron microscopy(SEM)analysis of TPS showed that the starch granules were damaged and gelatinized in the extrusion process.The density of TPS was 1.3695 g/mL,lower than that of palm starch,and the addition of stearic acid resulted in increased TPS density.X-ray diffraction(XRD)results showed that palm starch had a C-type pattern crystalline structure.The tensile strength,elongation at break,and modulus of elasticity of TPS were 7.19 MPa,33.95%,and 0.56 GPa,respectively.The addition of stearic acid reduced the tensile strength,elongation at break and modulus of elasticity of TPS.The rheological properties,i.e.,melt flow rate(MFR)and viscosity of TPS,were 7.13 g/10 min and 2482.19 Pa.s,respectively.The presence of stearic acid in TPS resulted in increased MFR and decreased viscosity values.The peak gelatinization temperature of A.pinnata palm starch was 70°C,while Tg of TPS was 65°C.The addition of stearic acid reduced the Tg of TPS.The thermogravimetric analysis(TGA)analysis showed that the addition of glycerol and stearic acid decreased the thermal stability,but extended the temperature range of thermal degradation.TPS derived from A.pinnata palm starch by extrusion method has the potential to be applied in industrial practice as a promising raw material for manufacturing bio-based packaging as a sustainable and green alternative to petroleum-based plastics.

Effects of Chinese chestnut powder on starch digestion,texture properties,and staling characteristics of bread

Chestnut is a high nutritional value food that has been widely used as a tonic in traditional Chinese medicine.As an emerging functional food ingredient,Chinese chestnuts are rich in a range of bioactive nutrients such as starch,dietary fiber,fat,protein,trace metal element and vitamins A,B,C,D and other nutrients.In our study,Chinese chestnut powder(CCP)were added into bread formulation at 2%-6%levels(based on flour weight)to produce fresh bread with enhanced anti-staling characteristics and starch digestion inhibitory ability.The texture properties,retrogradation enthalpy,water distribution,and estimated glycemic index(eGI)of wheat bread containing CCP as a functional additive were also investigated.The results showed that incorporation of CCP apparently affected bread texture,resulting in increased hardness,as well as decreased the specific volume of wheat bread.These influences were generally proportional to the amount of CCP used.It was found that adding too much CCP resulted in a dark red color,showing increased significantly higher total color difference(ΔE)and L values.Conversely,addition of CCP significantly reduced starch digestion rate and digestion extent in bread,and the reduction degree was positively related to the amount of CCP applied.The greatest reduction in eGI value from 79.40(control)to 75.02(6%CPP bread)was observed.Meanwhile,the content of resistant starch of 6%CPP bread was about 1.36 times higher than that of control bread.CCP also reduced crumb water loss and drove the water shift from the bound to the mobile state after stored for 7 days.The retrogradation enthalpy analyses further confirmed that CCP inhibited starch retrogradation and recrystallization.These results suggested that Chinese chestnut powder could be incorporated into fresh bread to provide health functions,such as lowering potential glycaemic response and improving anti-staling characteristics of bread.

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.

湿热处理对红薯淀粉特性的影响

为了研究湿热处理对红薯淀粉理化和结构等特性的影响,以五种红薯淀粉为实验对象,测定并分析湿热处理后淀粉溶解度、膨润力、持水力、透光率、凝沉性等理化特性的变化情况,进而探明湿热处理对不同初始含水量红薯淀粉吸水特性及晶体结构的影响规律。结果表明,经湿热处理后红薯淀粉的溶解度、膨润力、凝沉性与透光率均较原淀粉降低,持水力均增强,且五种红薯淀粉均呈现相同趋势,说明红薯品种与湿热处理对淀粉性质的影响规律无显著相关性。经湿热处理后红薯淀粉未见新的衍射特征峰,晶体类型仍为C型,而衍射强度和结晶度降低。湿热处理淀粉吸水达到平衡所需要时间较原淀粉短,且饱和吸水量较原淀粉有减小的趋势。利用Peleg模型方程模拟湿热处理后红薯淀粉的吸水规律,并计算出浸泡动力学吸水常数K1和K2,确定了淀粉的吸水动力学方程,可预测湿热处理后红薯淀粉在浸泡过程中的水分含量。