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.

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.

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.

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.

High amylose to amylopectin ratios in nitrogen-free diets decrease the ileal endogenous amino acid losses of broiler chickens

This study explored the variation of ileal endogenous amino acid(IEAA)losses and its influencing factors in chickens offered nitrogen-free diets(NFD)containing different ratios of amylose to amylopectin(AM/AP).A total of 252 broiler chickens at 28 d old were randomly allocated into 7 treatment groups for a 3-d trial.The dietary treatments included a basal diet(control),a NFD containing corn starch(CS),and 5NFD with AM/AP ratios of 0.20,0.40,0.60,0.80,and 1.00,respectively.As the AM/AP ratio increased,the IEAA losses of all AAs,starch digestibility and maltase activity linearly decreased(P<0.05),but the DM digestibility linearly and quadratically decreased(P<0.05).Compared with the control,the NFD increased the number of goblet cells and its regulatory genes mucin-2 and krüppel-like factor 4(KLF-4)while decreasing serum glucagon and thyroxine concentrations,ileal villus height,and crypt depth(P<0.05).Additionally,NFD with lower AM/AP ratios(0.20 and 0.40)decreased the ileal microbiota species richness(P<0.05).In all NFD groups,the number of Proteobacteria increased whereas the abundance of Firmicutes dropped(P<0.05).However,the broilers in the AM/AP 0.60 group were closer to the digestive physiological state of chickens fed the control diet,with no significant change in maltase activity and mucin-2 expression(P<0.05).In conclusion,increasing AM/AP ratio in a NFD decreased the IEAA losses and the apparent ileal digestibility of starch but inevitably resulted in malnutrition and disruption of gut microbiota homeostasis.This study recommends AM/AP in NFD at 0.60 to measure IEAA of broiler chickens.

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.

双波长光度法测定热处理橡胶木中支链淀粉和直链淀粉的含量

橡胶木中直链淀粉和支链淀粉的组成比例直接影响淀粉的化学特性,橡胶木热处理过程中,淀粉发生不同程度热降解影响其比例发生变化,分析其含量变化将为热处理橡胶木热解机制研究提供理论基础.研究采用单因素法优化了提取方法参数,并建立了双波长光度法检测橡胶木中直链淀粉和支链淀粉含量的定量分析方法,检验了该分析方法的精密度、稳定性和加标回收率.结果表明,直链淀粉和支链淀粉的标准曲线方程分别为y=0.02499x-0.1136和y=0.00159x-0.0005,其回归系数R^(2)均为0.998,方法前处理样品简便、快速,分析方法稳定性好、灵敏度高,回收率稳定,适用于橡胶木中直链淀粉和支链淀粉含量的定量分析.分析比较了橡胶木素材及不同温度(125、155、185℃)热处理橡胶木中直链淀粉和支链淀粉的含量,橡胶木素材中支链淀粉含量远高于直链淀粉,质量比约为8∶1.随着热处理温度升高至155℃,直链淀粉含量出现明显下降,而温度升高至185℃,支链淀粉含量出现明显下降趋势.

挤压螺杆转速对碎米重组米中淀粉多层级结构的影响

以碎米粉为原料,调整挤压螺杆转速,通过扫描电子显微镜图、小角X射线衍射图、X射线衍射图及傅里叶变换红外光谱对重组米的微观结构、淀粉糊体系亚微观结构和分形结构、长程有序、短程有序结构进行对比。研究发现:挤压处理后大米淀粉的螺旋构象发生变化,其表面孔隙变多,结晶结构发生明显改变。随着挤压螺杆转速逐渐降低,大米淀粉的分形维数、相对结晶度和双螺旋程度均逐渐下降,体系呈现疏松无序的状态。将直链淀粉和支链淀粉进行分离后发现,挤压处理可能导致直链淀粉与脂质形成少量复合物,支链淀粉的粒径最大达到1000μm以上,挤压使得颗粒表面更加粗糙。本研究对大米副产物的重构利用有着重要借鉴意义。

双波长法测定人参中淀粉含量

目的:建立双波长测定人参中直链淀粉和支链淀粉两类淀粉含量的方法。方法:以人参中直链淀粉和支链淀粉为研究对象,测定不同生长年限林下山参和园参中直链淀粉和支链淀粉含量并分析其分布规律,以碘比色法中双波长法为检测方法,对测定条件和方法进行优化,最后通过方法学验证最佳方法的准确性。结果:根据双波长法的测定原理和扫描光图谱,确定直链淀粉的测定波长和参比波长分别为600、471 nm;支链淀粉测定波长和参比波长分别为540、702 nm。直链淀粉和支链淀粉质量浓度分别在0.004~0.060(r=0.9998)、0.02~0.16 mg·mL^(-1)(r=0.9997)时具有良好的线性关系。平均加样回收率分别为100.03%和101.84%,RSD分别为1.29%和1.92%。结论:该方法操作简便,准确性、稳定性和重复性均良好,适用于人参中直链淀粉和支链淀粉含量的测定,可为人参的质量控制提供参考。

直链/支链比对青稞淀粉凝胶与消化性的影响

为深入探讨不同直链/支链比例对淀粉凝胶特性和消化行为的影响,本研究选取糯青稞和普通青稞品种,通过提取淀粉并复配制备直链/支链比例8%、14%、20%、25%的青稞淀粉,比较其在结晶结构、糊化特性、凝胶特性以及消化性方面的差异。结果表明,直链/支链比例未改变青稞淀粉的晶型,但直链/支链比例的增加降低了结晶度,使淀粉内部结构更紧密、双螺旋结构更稳定。同时,随着直链/支链比例的增加,淀粉糊化时的峰值黏度(3296~4226 mPa·s)逐渐降低、回生值(481.67~1604.33 mPa·s)逐渐增加。流变学结果表明,淀粉存在弱凝胶行为(G′>G″),淀粉凝胶的弹性行为增强会增加硬度和咀嚼度。消化特性方面,直链/支链比例的增加会增加抗性淀粉含量,降低快速消化淀粉含量、淀粉消化率和预估血糖生成指数。本研究结果对开发具有特定工业用途的功能性“定制”青稞淀粉具有一定的理论价值。

应用CRISPR/Cas9基因编辑技术获得高直链淀粉水稻种质

【目的】通过CRISPR/Cas9基因编辑技术遗传改良水稻种质,创制高直链淀粉新材料。【方法】以水稻品种中花11为试验材料,利用CRISPR/Cas9编辑系统对水稻淀粉分支酶(Starch branching enzymes,SBE)基因OsSBE3进行靶向编辑,利用PCR技术鉴定无标记纯合突变体,并测定其淀粉含量。【结果】T_(0)代获得10株突变体株系,T1代获得5个无标记纯合突变株系,其中4个株系(sbe3-22-6、sbe3-25-3、sbe3-25-4、sbe3-25-6)的直链淀粉含量和淀粉直支比显著高于野生型。【结论】本研究创制了高直链淀粉含量的水稻新种质,为水稻品质改良提供了参考。

不同基因型糯性大麦籽粒抗性淀粉含量及积累特性分析

为探明直链淀粉、支链淀粉和β-葡聚糖对抗性淀粉合成的影响,以30份不同基因型糯性大麦为试验材料,分别测定开花后期(灌浆初期)7、14、21 d和成熟期淀粉各组分、β-葡聚糖含量及抗性淀粉含量。结果表明:30份不同基因型大麦成熟籽粒淀粉组分、β-葡聚糖含量和抗性淀粉含量表现出显著差异。抗性淀粉含量范围为0.28%~1.22%,平均值为0.56%,品系西C1抗性淀粉含量最高,为1.22%,甘垦糯3号次之,为0.91%;抗性淀粉含量最低的两个品系为2014(7)-5-1-2(0.28%)、2014(1)-1-2-1(0.29%)。随着灌浆进程推进,甘垦糯3号抗性淀粉含量呈升高趋势,成熟期达到最大值;品系2014(1)-1-2-1呈先升高再降低的趋势,品系西C1和品系2014(7)-5-1-2则与品系2014(1)-1-2-1的变化趋势正好相反。30份大麦材料中有13个材料β-葡聚糖含量高于6%,是典型的高β-葡聚糖材料,其中中糯8号的β-葡聚糖含量高达8.59%。直链淀粉含量范围为1.81%~18.54%,支链淀粉含量范围为81.46%~98.19%,30份大麦材料中有22份材料支链淀粉含量>90%,是高支链淀粉材料。30份不同基因型大麦籽粒抗性淀粉含量不同,抗性淀粉积累特性不同。相关分析表明,抗性淀粉含量与直链淀粉含量呈极显著正相关,与β-葡聚糖含量呈显著负相关。

南瓜淀粉组分高效检测体系建立及应用

旨在建立高效的南瓜淀粉组分检测技术,以期提高定向育种和合理开发南瓜新品种的效率。根据双波长比色原理,利用提纯的南瓜直链淀粉和支链淀粉,通过等吸收点作图法,确定南瓜淀粉组分测定波长和参比波长。通过单因素比较试验,确定双波长测定南瓜淀粉组分的200μL反应体系。最后比较不同类型的南瓜淀粉组分含量,筛选极端材料。结果表明,直链淀粉的测定波长为616 nm、参比波长为472 nm,南瓜支链淀粉的测定波长为545 nm、参比波长为725 nm。建立南瓜直链淀粉和支链淀粉回归方程,直链淀粉浓度在0.0125~1 mg/mL、支链淀粉浓度在0.025~2 mg/mL范围内,线性关系良好(R2>0.9900)。96孔板200μL反应体系为待测液20μL、醋酸盐缓冲反应液(pH 3.5)90μL、12倍碘液稀释液90μL。供试23份南瓜材料的直链淀粉含量在0.52~26.68 mg/g果肉鲜重,支链淀粉含量在0.03~76.13 mg/g果肉鲜重,淀粉总量在0.55~101.61 mg/g果肉鲜重。以10和15 mg/g果肉鲜重、35和45 mg/g果肉鲜重、55和65 mg/g果肉鲜重,可以分别初步评价供试南瓜直链淀粉、支链淀粉和总淀粉含量低、中、高的情况。中印南瓜自交系比供试中国南瓜和印度南瓜的淀粉组分含量均高,最终筛选到7个中印南瓜自交系,用以淀粉定向育种潜力大。该试验获得的南瓜淀粉组分高效检测体系,对提高南瓜淀粉育种效率,行之有效。

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.

叶面喷施钼锌肥对冬小麦籽粒品质的影响

【目的】探明钼锌肥配施对冬小麦籽粒品质的影响,为钼锌肥的应用及冬小麦籽粒品质的改善提供参考。【方法】在河南省冬小麦产区开展叶面喷施钼锌试验,以喷施清水为CK,设置喷施0.10%钼肥、喷施0.10%锌肥、喷施0.10%钼肥+0.10%锌肥处理,考察不同处理小麦籽粒品质的变化。【结果】叶面单独施钼、单独施锌和钼锌配施能有效提高冬小麦籽粒中支链淀粉含量,在一定程度上能增加淀粉总量;钼锌配施能有效提高冬小麦籽粒中醇溶蛋白和麦谷蛋白含量。与CK相比,钼锌配施冬小麦籽粒中钼含量提高0.03~0.09 mg/kg,增幅为10.34%~39.13%;锌含量增加0.88~4.34 mg/kg,增幅为3.65%~18.11%。【结论】冬小麦叶面喷施钼肥与锌肥均能有效提高籽粒中支链淀粉含量,钼锌配施能有效提高籽粒中醇溶蛋白和麦谷蛋白含量,钼锌肥在优质冬小麦生产中具有较高的应用价值。

不同烘烤工艺对烟草CB-1上部叶抗性淀粉含量的影响

为明确烘烤过程中主变黄温度对烟草抗性淀粉含量的影响,以福建主栽品种翠碧一号(CB-1)上部叶为试验材料,在烤后烟叶上喷洒α-胰淀粉酶和淀粉葡糖苷酶的混合溶液,测定喷洒酶液后烤后烟叶中淀粉含量,探究烤后烟叶中是否存在抗性淀粉。以当地常规烘烤工艺为对照,设置不同主变黄温度,探究主变黄温度对抗性淀粉含量的影响,旨在为降低烤后烟叶抗性淀粉含量提供参考。结果显示:(1)喷洒α-胰淀粉酶和淀粉葡糖苷酶溶液后,烤后烟叶淀粉含量无显著差异,表明烤后烟叶中存在抗性淀粉;(2)烟叶变黄前中期,直链淀粉、支链淀粉以及抗性淀粉均大量降解;(3)主变黄温度影响抗性淀粉含量,其中,当主变黄温度为38℃时,延长主变黄时间,可有效降低烤后烟叶中抗性淀粉含量;(4)烤后烟叶直链淀粉与抗性淀粉含量存在显著正相关关系。综合分析认为,对福建主栽品种CB-1采用中温变黄烘烤工艺,延长主变黄时间,可降低烤后烟叶抗性淀粉含量,进而为降低烟叶淀粉含量和改善烟叶品质提供参考。

直链/支链淀粉对鱼丸质构特性及感官品质的影响

为探究直链/支链淀粉对不同来源(海水鱼/淡水鱼)鱼丸的质构特性以及感官品质的影响,采用质构剖面分析法(texture profile analysis,TPA)测定鱼丸的质构特性,结合感官品质评定方法对鱼丸质构进行综合评定,并辅以持水性分析和微观结构观察,研究鱼丸凝胶性质。结果表明:相对于直链淀粉,支链淀粉在鱼丸加工工艺中能更有效地提高其硬度和咀嚼性。以鲅鱼肉作为鱼丸原料相较于巴沙鱼肉具有更高的蛋白质及更低的脂肪含量,更为优越的质构特性、感官品质以及持水性。

碘比色法测定高粱中直链淀粉和支链淀粉的方法探讨

目的:高粱中淀粉含量与其衍生物的品质密切相关,对其中直链淀粉(Am)和支链淀粉(Ap)含量的测定很有必要。本文采用碘比色法对高粱籽粒中淀粉(Am、Ap)含量的进行测定,探讨最佳预处理与检测方法。方法:以高粱籽粒中的Am与Ap为主要研究对象,比较碘比色法中的三种检测方法,即:单波长混标法(Ⅰ)、双波长单标法(Ⅱ)及双波长混标法(Ⅲ),通过精密度、检出限、定量限等对三种测定方法进行了一系列的方法学验证,并对预处理及测定过程中NaOH和KOH分散剂、糊化温度、糊化时间、乙酸和盐酸p H调节剂、碘试剂用量和显色时间进行了比较优化,最后通过重复性验证、回收率验证和常见谷物样品的测定验证了最佳方法的准确性。结果:三种方法的检出限和定量限均能满足实际样品的测定范围需求,其中检出限:Am均≤0.55 mg/L,Ap均≤2.75 mg/L,定量限:Am均≤1.65 mg/L,Ap均≤8.33 mg/L;样品准确率实验发现,混标溶液标曲得到的误差绝对值较小(0.13%),但单标溶液标曲误差较大(7.47%),因此需要选用混标溶液配制标曲;高粱籽粒中淀粉的最佳预处理与测定条件是:以NaOH作分散剂,以乙酸或盐酸为p H调节剂,70℃糊化10~20 min,采用标准碘试剂浓度,显色20~30 min内测定结果较为稳定、准确;测定方法中,双波长混标法(Ⅲ)所测定的Am、Ap及总淀粉含量准确,且与理论粗淀粉含量吻合,重复性和回收率(80%~120%)高。结论:碘比色双波长混标法是测定高粱籽粒中直链淀粉和支链淀粉含量的最佳测定方法,可用于实际样品的测定。

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.

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.