响应面试验优化晶种诱导-双酶复合法制备RS_3型籼米抗性淀粉工艺

以微波预糊化籼米淀粉为原料,自制RS_3型马铃薯抗性淀粉为晶种,研究RS_3型籼米抗性淀粉的晶种诱导-双酶复合法制备工艺。利用扫描电子显微镜对淀粉颗粒形貌进行表征并研究淀粉的抗酶解性。在单因素试验的基础上,固定其他酶解条件,以RS_3型籼米抗性淀粉产率为响应值,确定晶种添加量、异淀粉酶添加量、普鲁兰酶添加量和普鲁兰酶酶解时间作为影响产率的主要因素,进行Box-Behnken响应面优化试验。得到RS3型籼米抗性淀粉的最佳制备工艺条件为:晶种添加量5%、异淀粉酶添加量8 U/g、普鲁兰酶添加量8 U/g、普鲁兰酶酶解时间3.50 h。在此最佳制备工艺条件下,RS_3型籼米抗性淀粉产率为27.42%,RS3失去原有的淀粉颗粒形貌,表面变得粗糙,结晶结构致密,具有较强抗酶解能力。     

超声辅助双酶法制备RS_3型籼米抗性淀粉工艺参数优化

以微波预糊化籼米淀粉为原料,采用超声波间歇式辅助,异淀粉酶和普鲁兰酶分步脱支酶解制备了RS_3型籼米抗性淀粉。以RS_3产率为考察指标,在单因素实验的基础上,利用响应面法对制备RS_3型籼米抗性淀粉的工艺参数进行了优化。结果表明,在淀粉乳质量分数10%、异淀粉酶酶解温度50℃、异淀粉酶酶解pH5.0、普鲁兰酶酶解温度60℃、普鲁兰酶酶解pH4.5、超声功率70 W条件下,最佳工艺条件为:异淀粉酶添加量16 U/g,异淀粉酶酶解时间3 h,普鲁兰酶添加量8 U/g,普鲁兰酶酶解时间2.2 h,超声时间7 min,超声间歇时间2.3 h。在最佳条件下,RS_3型籼米抗性淀粉产率可达18.19%。     

超声酶解法制备玉米抗性淀粉的结构及性质

探讨超声酶解联合处理及添加剂对抗性淀粉(RS_3)得率、结构及性质的影响,研究以玉米淀粉为原料,采用超声辅助酶解法制备抗性淀粉,考察超声时间、加酶量及添加剂种类和用量对RS_3得率的影响。通过扫描电子显微镜(scanning electron microscope,SEM)、差式扫描量热法(differential scanning calorimetry,DSC)、红外线(Infrared Radiation,IR)及X-射线衍射(X-rory diffraction,XRD)对RS_3的结构表征,对其性质测定。结果表明,当超声处理原淀粉乳10 min,α-淀粉酶10 U/g,添加淀粉质量2%的海藻酸钠,RS_3得率为11.92%。扫描电镜分析表明,与原淀粉相比,RS_3的形貌及结晶性均发生变化,原来的规则的多面体小颗粒粉末状转为表面布满褶皱的粒径明显增大的雪片状蓬松结构;差热分析表明RS_3主要由直链淀粉重结晶而成,淀粉的热稳定性提高;原来的A型结晶变为抗性淀粉的B型,结晶度增加。性能测试表明,与原淀粉相比,RS_3的含水率和透光率均降低,比容积减小,乳化性稍有增加。抗性淀粉的结构更紧密,热稳定性抗酶解性更高。为探索提高玉米抗性淀粉得率的新方法及其扩大在食品领域的应用发展提供参考。     

超声波-酶法制备小麦RS3型抗性淀粉工艺参数的优化

以小麦淀粉为原料,抗性淀粉得率为指标,采用超声波-酶法制备小麦RS3型抗性淀粉,在优化的超声波作用条件(淀粉乳浓度15%,超声波功率225W,超声温度50℃,超声作用时间50min)基础上,通过单因素及正交试验确定最佳的酶解工艺:耐高温α-淀粉酶添加量1U/g干淀粉,耐高温α-淀粉酶作用时间20 min,普鲁兰酶添加量10 U/g干淀粉,普鲁兰酶酶解温度50℃,酶解时间7 h。经反复验证,超声波-酶法制备小麦RS3型抗性淀粉得率为13.155%。     

发酵乳中抗性淀粉的变化及对凝胶过程的影响

研究抗性淀粉在发酵乳中的作用,选用RS_2型玉米抗性淀粉(G)和微波-湿热法制备的RS_3型马铃薯抗性淀粉(W),研究它们在发酵乳加工、贮藏过程中含量和形态的变化。以未添加抗性淀粉的发酵乳为对照,观察其微观结构,分析发酵乳凝胶过程的流变学特性与稳定性。结果表明:W相对于G残留量较高且维持在60%左右;2种抗性淀粉均保留着淀粉颗粒形态,有不同程度的损耗,主要集中在发酵后期与贮藏期;W更有利于发酵乳形成完整、均一的微观结构;含W的发酵乳微观弹性较强且有利于酪蛋白颗粒结合形成更加坚固的结构;含W发酵乳的微观稳定性优于含G的发酵乳。     

超声-微波协同酶法制备芸豆抗性淀粉工艺优化及结构分析

探究超声-微波协同酶法制备芸豆抗性淀粉的最佳工艺条件及其物理结构特性。以紫花芸豆为试验材料,利用超声-微波协同酶法制备RS3型抗性淀粉,考察不同水平时淀粉悬浮液质量分数、超声时间、普鲁兰酶添加量和微波功率对抗性淀粉得率的影响,同时做响应面优化试验;通过扫描电镜、红外光谱、凝胶渗透色谱仪等方法分析芸豆淀粉及抗性淀粉的结构特性。结果表明:淀粉悬浮液质量分数16%、普鲁兰酶添加量12.5 ASPU/g(干基)、微波功率300 W、超声-微波协同处理20 min时,芸豆抗性淀粉得率最高为(24.37±0.41)%。与原淀粉相比,芸豆抗性淀粉颗粒破损,呈形状大小各异的块状碎石结构;抗性淀粉未出现新的特征吸收峰;处理后的芸豆抗性淀粉平均聚合度降低,多分散系数降低。超声-微波协同酶解法可提高芸豆抗性淀粉得率,抗性淀粉形成过程中淀粉官能团没有变化,其余结构特性改变。     

马铃薯抗性淀粉理化性质的研究

以马铃薯原淀粉为对照,研究了纤维素酶-压热法制备的马铃薯抗性淀粉的理化性质。结果表明,马铃薯原淀粉颗粒呈椭球形,表面光滑;而抗性淀粉的颗粒状结构消失,形成了连续的致密结构,表面不再光滑。红外光谱分析表明,抗性淀粉分子中未出现新的基团,只较原淀粉形成了更多的氢键。马铃薯原淀粉的分子晶型为A型,整体结晶度为22.82%;抗性淀粉的分子晶型为B型,整体结晶度为29.64%。马铃薯抗性淀粉的溶解度、透明度远远低于原淀粉;膨润度、持水性优于原淀粉。抗性淀粉的沉降速度较快,沉降性比原淀粉强。原淀粉糊化温度为65.8 ℃,峰值黏度可达到10 770 mPa·s;而抗性淀粉其糊化温度高于95 ℃。     

酶解处理对大米RS_3型抗性淀粉产率的影响

以大米淀粉为原料,研究比较了α-淀粉酶、葡萄糖淀粉酶和普鲁兰酶对大米RS3型抗性淀粉产率的影响,试验结果表明:普鲁兰酶对大米RS3型抗性淀粉产率影响最为显著,抗性淀粉产率相对较高。在酶法制备大米RS3型抗性淀粉过程中,α-淀粉酶在最佳添加量为1%、酶解30 min、淀粉浓度均为10%条件下,抗性淀粉产率可达14%;葡萄糖淀粉酶在酶添加量为0.5%、酶解20 min、淀粉浓度均为10%条件下,抗性淀粉产率可达15%左右;普鲁兰酶添加量为40μL/g淀粉、酶解12 h、淀粉浓度为20%条件下,大米RS3型抗性淀粉产率高可达20.57%。研究结果可为酶法制备大米RS3型抗性淀粉提供参考。     

物理协同酶法处理对青稞淀粉结构的影响

为研究物理协同酶法处理对青稞淀粉结构特性的影响,采用超声、压热协同普鲁兰酶对青稞淀粉进行处理,测定了处理后样品的颗粒形貌、晶体结构、官能团结构、粒径大小。试验结果表明,处理可以提高抗性淀粉和直链淀粉含量,降低支链淀粉的含量。改性处理使青稞淀粉颗粒的原始结构遭到了严重破坏,呈现出团状结构,表面粗糙,布满褶皱、裂纹和孔洞;淀粉的偏光十字消失。改性后的青稞淀粉表面积平均粒径增大,大颗粒数目增加。物理协同酶法处理增加了青稞淀粉的结晶度,晶型由A型晶体向B型转变。改性处理没有产生新的化学基团和化学键,只是改变了青稞淀粉内部结构的重新排列。此外与青稞原淀粉相比,改性青稞淀粉的有序度（DO）值增大,其中普鲁兰酶处理后的青稞淀粉的DO比值最大。改性处理使青稞原淀粉颗粒中的淀粉分子分解成小分子又重新结晶,形成的改性青稞淀粉含有更加致密的大淀粉晶体。     

蚕豆淀粉与其抗性淀粉理化性质的比较

本文系统比较分析了压热法制备蚕豆抗性淀粉前后理化性质的变化。结果表明,蚕豆淀粉的溶解度、膨润度、透明度和平均聚合度均大于蚕豆抗性淀粉,但持水性小于抗性淀粉。蚕豆淀粉颗粒呈椭球形,表面较为光滑,分子晶型为A型,整体结晶度为10.3%;而蚕豆抗性淀粉颗粒为不规则形、多角形,表面粗糙褶皱,尺寸较小,分子晶型为C型,整体结晶度为11.7%。与蚕豆淀粉相比,抗性淀粉红外光谱中的-OH伸缩振动峰峰形变宽且发生了红移,蚕豆淀粉的糊化温度为65.84℃,显著低于抗性淀粉的151.19℃。表明压热制备抗性淀粉理化性质被改变,有氢键参与了抗性淀粉的生成,晶体结构的致密度提高。     

穇子抗性淀粉理化性质及体外消化研究

以穇子淀粉为原料,通过超声—压热法制备穇子抗性淀粉(RS₃),探讨了穇子RS₃的理化性质和消化特性。结果表明:与穇子淀粉相比,穇子RS₃具有较好的溶解度、热稳定性和冻融稳定性;而膨胀度、凝沉性较小,这些特点可以用来改善食品的质地,增加食品的脆度。与普通玉米RS₃相比,穇子RS₃具有更好的冻融稳定性和凝沉性。电镜结果显示,穇子RS₃表面比玉米RS₃粗糙很多。从体外消化来看,穇子RS₃具有比玉米RS₃更强的抗消化能力,可用来开发降血糖功能性食品。     

Research advances on the formation mechanism of resistant starch type III: A review

Abstract

Resistant starch (RS) plays a key role in providing metabolic and colonic health benefits. In particular, RS type III (RS₃) is of great interest because of its thermal stability and its preserved nutritional functionality. RS₃ can be prepared by physical treatment, including high hydrostatic pressure, ultrasound, extrusion, autoclaving, microwave cooking, and heat-moisture treatment. The acid and enzymatic hydrolysis can also be applied to facilitate the generation of small molecules, which increases the inherent crystallinity of RS₃ upon retrogradation. Depending on processing conditions, RS₃ with diversified structural characteristics can be formed. These structures play a key role in determining the physiological behavior of RS₃. Therefore, a deep understanding of the structural rearrangement pattern during different processing treatment is of great importance for regulating the molecular structure of RS₃ and thereby its corresponding physiological properties. This review thus focuses on the past and current status of research into the in-depth study of RS₃ formation mechanism and the changes to RS₃ structural characteristics under different processing conditions. The objective was to provide a theoretical guidance for the rational selection of preparation methods for RS₃ and for designing RS₃ structures with specific physiological functionalities for relevant industrial applications.     

Biodiversity of Legume Health‐promoting Starch

The content of retrograded resistant starch (RS₃) and RS₃/total starch ratio was determined in 74 cultivars of six legumes currently found in human food. There were significant differences in individual crops as well as their cultivars. All analysed legumes (except soybean) are a suitable natural source of health‐promoting RS₃. The highest levels of RS₃ were found in peas. There were extensive differences in RS₃ content and RS₃/total starch ratio in the latter crop types. Higher resistant and lower total starch amounts were found in wrinkle seeded peas. Maximal RS₃ content was detected in Ctirad, Dinara, Royal Salute and Elkan cultivars. In smooth seeded peas, lower resistant and higher total starch were estimated. High RS₃ levels were also observed in lentils, especially in the LCMB12/58 and LCMB1941 cultivars. Similar RS₃ values were found in the chickpea, faba bean and kidney bean. The highest RS₃ levels were demonstrated in the kidney bean Ultima, Fabia, 545/97472 and 545/974532; chickpea Alfa, CM7185, BG004233, PK51814 and 88199; and faba bean Alfréd and Omar cultivars. No soybean cultivar was found to be a suitable source of RS₃.     

玉米淀粉、籼米淀粉薄荷酮复合物的结构和释放性能的比较

采用共沉淀法制备玉米淀粉薄荷酮复合物及籼米淀粉薄荷酮复合物,并对2种淀粉复合物复合率进行测定,玉米淀粉薄荷酮复合物复合率为43.8%,籼米淀粉薄荷酮复合物复合率为24.7%。对2种淀粉复合物结构进行表征,通过CP-MAS13C NMR、XRD、红外及扫描电镜对复合物进行分析。核磁中新峰的出现及淀粉骨架的化学位移、XRD衍射新峰的出现及结晶度的变化及复合物形成前后表面形态的明显变化,证明了淀粉复合物的形成。利用Avrami方程对2种淀粉薄荷酮复合物在4、25℃,相对湿度33%、75%、90%条件下的释放情况进行分析,结果表明,低湿低温环境中贮藏的复合物更加稳定,且玉米淀粉薄荷酮复合物的贮藏稳定性高于籼米淀粉薄荷酮复合物。     

单糖对莲子淀粉回生特性的影响

从晶体结构、分子结构以及分子量等方面研究单糖(葡萄糖和果糖)对莲子淀粉回生特性的影响。X-射线衍射、核磁共振与红外光谱研究结果表明,葡萄糖和果糖能够抑制莲子淀粉重结晶,复合体系中结晶度、双螺旋结构和短程有序结构减少、无定型区占比增加,说明葡萄糖和果糖抑制淀粉回生。葡萄糖抑制淀粉回生的作用更为显著,可能与葡萄糖—水分子间相互作用增强有关。凝胶渗透色谱分析结果显示,与单一莲子淀粉相比,葡萄糖与莲子淀粉复合体系的分子量M_n和M_w显著增加,而果糖体系的M_n和M_w明显降低;提示葡萄糖促进淀粉分子量的增加是其影响体系回生的关键因素。     

油莎豆辛烯基琥珀酸淀粉酯的制备及结构表征

以油莎豆淀粉为原料,以辛烯基琥珀酸酐为酯化剂,选用水相法制备OSA淀粉酯.对不同OSA用量的油莎豆OSA淀粉酯的糊液透明度、冻融稳定性、抗性淀粉含量和接触角进行分析,通过傅里叶红外光谱、扫描电镜和X-射线衍射对淀粉酯结构进行表征.结果表明:油莎豆OSA淀粉酯取代度随OSA用量的增加而增大,反应效率与之相反.淀粉酯糊液透...     

Techno‐functional properties of wheat flour‐resistant starch mixtures applied to breadmaking

Resistant starch can be used to reduce the availability of carbohydrates in baked products. In this study, the effect of type 4 resistant wheat starch (RS₄) on wheat flour dough and breads was evaluated. Wheat flour was substituted by RS₄ at 10%, 20% and 30% w/w (RS10, RS20 and RS30, respectively). Rheological and thermal behaviours of dough were evaluated. Besides, bread quality, starch digestibility and bread staling were analysed. All substituted dough exhibited viscoelastic behaviour but lower elastic and viscous moduli. Regarding to bread quality, specific volume and crumb texture were negatively affected in samples with RS₄. However, all samples were technologically acceptable. During storage, crumb hardening was observed in breads without and with RS₄ but amylopectin retrogradation was not particularly affected. The in vitro digestibility of bread with RS showed a lower release of reducing sugars and a lower estimated glycaemic index, suggesting a healthier profile for these breads.     

Annealing processing technique divergently affects starch crystallinity characteristic related to resistant starch content: a literature review and meta-analysis

Annealing is one of starch physical modification techniques that can increase resistant starch (RS) content. However, the effect of annealing on RS varies based on botanical sources. Starch crystal type and relative crystallinity are two important characteristics of starch. This study aimed to compare the influence of annealing on starch crystallinity and different starch crystal type (A, B and C) and investigate its effect on RS content by literature meta-analysis study. The literature review was carried out using 22 research articles and 101 data points. The result showed relative crystallinity increase from the highest changes to the lowest, respectively; C-type crystal (18.98%) followed by B (13.60%) and A-type crystal (8.17%). Meta-analysis study results showed a significant increase of RS content on starches with A-type crystal (SMD = 6.46; 95% CI: 3.22–9.70; P < 0.01) and a positive relationship between the degree of crystallinity and RS content after annealing modification.     

Structure and Properties of Starch in Rice Double Mutants Lacking Starch Synthase (SS) IIa and Starch Branching Enzyme (BE) IIb

Starch biosynthetic enzymes form multi-protein complexes consisting of starch synthase (SS) I, SSIIa, and starch branching enzyme (BE) IIb, which synthesize amylopectin clusters. This study analyzed the starch properties in two double mutant rice lines lacking SSIIa and BEIIb, one of which expressed an inactive BEIIb protein. The ss2a be2b lines showed similar or greater seed weight than the be2b lines, and plant growth was not affected. The ss2a line showed increased short amylopectin chains resulting in a lower gelatinization temperature. Starch granule morphology and A-type crystallinity were similar between the ss2a line and the wild type, except for a mild chalky seed phenotype in the ss2a line. However, the starch phenotype of the ss2a be2b lines, which was similar to that of be2b but not ss2a, was characterized by increased long amylopectin chains, abnormal starch granules, and B-type crystallinity. The similarity in phenotype between the ss2a be2b and be2b lines may be attributed to the inability of the be2b mutants to generate short amylopectin branches, which serve as primers for SSIIa. Therefore, the presence or absence of SSIIa hardly affected the amylopectin structure under the be2b background. The amylose content was significantly higher in the ss2a be2b lines than in the be2b lines. Starch crystallinity was greater in ss2a be2b lines than in be2b lines, despite the fact that starch crystallinity is generally negatively correlated with amylose content. This suggests that the formation of a double helix between long amylopectin chains and amylose affects starch crystallinity in the ss2a be2b mutants.