物理法制备RS3型抗性淀粉的研究进展

抗性淀粉是指在健康人体小肠不被消化和吸收的多糖类物质，对人体健康有益。回生淀粉(RS3)作为抗性淀粉的其中一类，因具有热稳定性好、持水性低等特点，在食品工业中被广泛应用。本文分别综述了近年来超声法、微波法、湿热法以及韧化法制备RS3型抗性淀粉对其得率、理化性质和结构的影响，并对物理法制备RS3型抗性淀粉的现状提出展望，以期为物理法制备RS3型抗性淀粉的研究提供有益的参考，促进物理法制备抗性淀粉的实际应用。     

甘薯抗性淀粉研究进展

甘薯是重要的淀粉作物,其块根中抗性淀粉（resistant starch,RS）含量较高,具备良好的产品开发潜力。要进一步促进甘薯RS的应用和推广,不仅需要筛选或培育出RS含量更高的甘薯品种,还需要加大开发甘薯深加工淀粉产品。除调控淀粉合成相关基因的表达外,生产实际中还可通过调整栽培措施等方式提高甘薯RS的含量。通过化学修饰法、物理法和酶解法等方法可制备甘薯RS产品,也能提高产品中RS的含量。本文系统综述了近年来甘薯淀粉的保健效果、RS含量的测定方法、影响甘薯淀粉中RS含量的因素、RS的制备方法及其特性等方面的进展,为未来甘薯中RS的制备、产量提高、产品开发和推广提供理论依据和技术指导。     

酶法纯化何首乌抗性淀粉及其对大肠杆菌增殖效力的影响

为优化何首乌抗性淀粉（resistant starch,RS）的纯化工艺,并考察其对大肠杆菌增殖效力的影响。基于单因素试验,采用Box-Behnken响应面法,以淀粉乳浓度、酶添加量、酶解时间为考察因素,RS含量为指标,优化RS纯化工艺;测定何首乌RS与纯化后RS的碘吸收曲线、平均聚合度;以RS为培养基碳源,采用体外发酵考察何首乌RS及纯化后RS对大肠杆菌增殖的影响。结果表明：最佳纯化条件为淀粉乳浓度16%、酶添加量22 U/g、酶解时间42 min条件下纯化RS,RS含量为（43.23±0.26）%。纯化后RS的碘结合能力明显提高,平均聚合度为47.03;纯化后RS表面呈现多孔结构。与葡萄糖培养基相比,纯化RS可显著降低大肠杆菌的增殖。     

RS3型抗性淀粉的研究进展

随着人们生活水平的提高以及膳食结构的改变,高血糖和高血脂等与饮食相关代谢紊乱疾病的发生率也逐渐增大。抗性淀粉作为一种新型膳食纤维,能显著影响人体代谢,改善因膳食结构不合理而引起的代谢综合症。抗性淀粉又称抗酶解淀粉,不能被人体胃和小肠的消化酶分解吸收,但可被结肠有益菌发酵产生乙酸、丙酸、丁酸等短链脂肪酸,具有调节糖脂代谢、改善肠道菌群结构和代谢等功能。作为RS3型抗性淀粉的回生淀粉(老化淀粉),与其他类型的抗性淀粉相比具有更高的热稳定性,且色泽白皙、无异味、持水性低、口感细腻,在食品工业中具有广阔的应用前景,受到了国内外学者的广泛关注。本文通过对RS3的制备方法、结构特性、生理功能及其在食品中的应用进行综述,以期为RS3型抗性淀粉的研究和开发提供参考和依据。     

慈姑抗性淀粉的理化特性研究

采用酸解- 微波法制备慈姑抗性淀粉(resistant starch,RS),结果发现慈姑RS 形成了新的连续的致密结构,结晶以初级微晶为主,晶型转变为C 型,结晶度为23.62%;RS- 碘复合物的最大吸收波长为564.40nm;随着RS含量的增加,慈姑RS 的直链淀粉含量变化不大,大部分可溶性直链淀粉转变为不溶性直链淀粉,平均聚合度明显降低,提纯RS 的平均聚合度为22.94;红外光谱分析表明,慈姑RS 含有伯、仲醇羟基和α-D- 吡喃环结构特征,只较原淀粉形成了更多的氢键,说明其是物理改性淀粉。慈姑RS 的溶解度、透明度大大低于原淀粉,而持水力较原淀粉有明显的提高。     

抗性淀粉用于微胶囊制备的研究进展

抗性淀粉是一种新型的膳食纤维资源,具备多种保健功能,由于其功能特性而日益受到人们的关注,且许多研究表明,抗性淀粉能降低糖尿病、结肠癌等疾病的发病风险。目前全球大约有1/3人口处于"三高"、超重、肥胖等营养不良的状况,亟需引导人们养成健康的生活习惯。前人研究表明抗性淀粉在胃和小肠中不被消化吸收,而在结肠中被微生物菌群发酵产生多种短链脂肪酸和气体,继而发挥益生作用。该文综述用于制备微胶囊的抗性淀粉种类(RS2、RS3、RS4)及其理化性质,其可有效保护益生菌的生长、可作为缓释载体、具有良好的挤出和膜成型质量,初步分析抗性淀粉基微胶囊的制备方法。此外,还归纳其在营养补充剂,缓释载体体系,以及作为益生元促进益生菌的增殖中的应用,以期为我国抗性淀粉产业提供参考。     

山西谷子全粉淀粉指标间相关性及消化特性研究

本文主要研究了77个山西谷子全粉样品中淀粉组分的相关性以及淀粉消化特性。分别测定了谷子金粉中淀粉、直链淀粉和抗性淀粉(RS)含量。制备谷子淀粉并分析了淀粉中快速消化淀粉(RDS)、慢速消化淀粉(SDS)、RS的含量以及淀粉消化指数(SDI)和持续消化淀粉(LS)。结果表明:各品种间RS含量差异性较大;全谷物以及制备得到的淀粉所测定的备指标间相关性较强。其中。谷子中RS与直链淀粉相关性最强(r=0.885),对谷子中RS聚类分析后发现。RS与直链淀粉近似呈线性相关(r=0.954)。对谷子淀粉体外消化研究表明:黄谷(2010)等品种中SDS舍量较高,晋谷21号(2010)等品种中RS含量较高,而陇谷10号(2012)等品种中LS含量相对较高,这些品种适用于糖尿病等人群食用或有助于开发相关降糖产品。     

土豆抗性淀粉的体外消化与发酵

研究了土豆回生淀粉(RS3)和交联淀粉(RS4)的体外消化动力学与体外人粪分批厌氧发酵。结果表明:土豆回生淀粉(RS3)和交联淀粉(RS4)中缓慢消化淀粉(SDS)与抗性淀粉(RS)的含量显著增加,两者属于低血糖指数(pGI)食物。以土豆回生淀粉(RS3)和交联淀粉(RS4)为唯一碳源发酵时,活的厌氧菌总数和双歧杆菌数都比原淀粉、Novelose 230(RS2)的要高,但乳酸杆菌数都出现不同程度的下降。四种淀粉样品都能促进短链脂肪酸(SCFAs)总量的增加,其中土豆回生淀粉(RS3)、交联淀粉(RS4)与Novelose 230(RS2)特别有利于促进丁酸的生成。土豆回生淀粉(RS3)与交联淀粉(RS4)能够改善人体肠道菌群的分布、促进SCFAs特别是丁酸的生成,具有开发成为新的益生素的潜力。     

食物中抗性淀粉的含量分析

对我国常见食品中可消化淀粉(DS)和抗性淀粉(RS)的含量进行分析,初步评价食品来源和加工方法对RS的影响。文中选择80种食物样品,依照AOAC 2002.2方法分析食物中DS和RS含量分析;并分析了不同直链淀粉比例、常规烹调加工方法下RS的含量。结果食物RS受来源和加工方法影响较大,豆类、生的薯类、饼干食品、含直链50%淀粉的玉米RS含量相对较高;淀粉中直链淀粉比例为50%时,RS含量较高;碾磨、蒸煮、膨化使RS含量降低,特殊工业加工的高RS产品蒸煮后RS不被破坏。     

小麦抗性淀粉的理化性质研究

利用压热法制备小麦抗性淀粉RS3,并考察其部分理化性质及结构性质。结果表明,该产品含抗性淀粉13.89%,透光率较好,持水力、溶解度和膨胀度都随水浴加热温度的升高而上升。其淀粉-碘复合物最大吸收波长为594 nm,碘吸收曲线在580~610 nm之间呈较宽的吸收峰。该产品颗粒形状大部分为圆形,偏光十字明显,多呈十字型,且交叉点均位于颗粒中心;起糊温度为68.7℃,糊化不易发生,但较易老化。淀粉颗粒结晶结构为C型,仍保留了小麦淀粉红外光谱的特征吸收峰。     

Resistant Starch and Health — Himalaya 292, a Novel Barley Cultivar to Deliver Benefits to Consumers

Dietary and lifestyle change is a recognised strategy for the management and prevention of socio‐economically important non‐infectious diseases. Dietary fibre is composed largely of non‐starch polysaccharides (NSP), and greater consumption of NSP‐rich foods relieves simple constipation very effectively. Starch (as resistant starch, RS) is also receiving attention for its potential role in promoting colonic function. Resistant starch is that fraction of starch which escapes human small intestinal digestion and enters the large bowel where (together with a variable fraction of NSP) it is fermented by the resident microflora. The resulting short chain fatty acids (SCFA) are taken up by the large bowel and metabolised. SCFA mediate many of the health benefits ascribed to NSP and RS. Starch consumption is low in affluent westernised countries, despite recommendations by health agencies. In Australia, foods enriched in RS as a high amylose maize starch have gained consumer acceptance. However, scope remains for additional products and ingredients and a company, Ascentia Pty Ltd, has been established to develop a novel barley cultivar (Hordeum vulgare var. himalaya 292) for this purpose. This cultivar has a specific gene alteration leading to a loss of starch synthetase lla activity resulting in a grain which is low in starch but disproportionately higher in amylose and also NSP. Animal and human studies have shown that Himalaya 292 is high in RS relative to existing products and has a low glycaemic index and the cultivar offers promise as a vehicle to deliver health benefits to consumers.     

抗性淀粉对SD大鼠的胃损伤预防效果研究

以抗性淀粉（RS2）为研究对象,构建动物模型,通过酶联免疫法、逆转录-聚合酶链式反应等方法研究其对HCl-乙醇诱导SD大鼠胃损伤的预防效果。结果表明：10% RS2、15% RS2和20% RS2均能降低大鼠的血清IL-6和TNF-α水平,大鼠的胃损伤程度,显著提高胃损伤的抑制率,均能减少胃液分泌量、增加胃液pH值,表现出一定的胃损伤预防效果。其中20% RS2对胃损伤预防效果最佳。     

Comparative Effects of Acetylated and Unmodified High‐amylose Maize Starch in Rats

Acetylated, propionylated or butyrylated starches raise the large bowel pools of these short chain fatty acids (SCFA) in rats but their resistant starch (RS) content in vivo is unknown. This content was determined for acetylated starch (Starch A, DS = 0.18) in colectomised rats and compared to a standard maize (control) or high‐amylose (HAMS) maize starch. Digestibilities were 99.8% (control), 47.5% (Starch A) and 58% (HAMS). The effects of Starch A and HAMS were compared also in intact rats, that were fed a fibre‐free diet in which either 200 g/kg of HAMS or 100, 200 or 300 g of Starch A/kg was substituted for the standard maize starch. Caecal SCFA pools were larger in rats fed either RS with the greatest increase being in acetate in rats fed Starch A. Other acids (succinate and formate) appeared with increasing incorporation of RS. However, when the experiment was performed with a commercial diet, feeding Starch A or HAMS did not lead to any great increase in these other acids but SCFA pools expanded. The greatest increase in acetate was in rats fed Starch A. This suggests that other factors were necessary for optimal RS fermentation but not for release of acetate from Starch A. Comparison of the effects of Starch A and HAMS on SCFA suggests that the former was at least 100% more effective than HAMS at equivalent dietary intakes, despite similarities in RS content. Incubation of Starch A with caecal bacterial enzymes confirmed that release of acetate was relatively slow, indicating a capacity of this modified starch for sustained SCFA delivery in vivo.     

制备过程中淀粉浓度对莲子回生淀粉理化特性的影响

本文从热稳定性、膨胀度及溶解度、黏度、流变特性等方面研究制备过程中淀粉浓度对莲子回生淀粉(Retrograded starch,RS)理化特性的影响。热重分析(Thermogravimetric analysis,TGA)结果表明,5%及40%淀粉浓度下的回生淀粉含有较多易挥发物质,20%淀粉浓度下的回生淀粉含有较多相对热稳定组分。随着淀粉浓度增加,莲子回生淀粉膨胀度减小,溶解度增大,黏度递减,且样品膨胀度及溶解度随温度升高而增加。由静态流变结果可知,所有样品均表现出剪切稀化特性,且5%、10%及20%淀粉浓度下的回生淀粉的黏度高于30%、40%及50%淀粉浓度下的回生淀粉的黏度;由动态流变结果可知,当角频率小于10 rad·s-1时,所有样品的储存模量均不受角频率影响;当角频率大于10 rad·s-1时,5%、10%及20%淀粉浓度下的回生淀粉的储存模量随角频率增加而减小,而30%、40%及50%淀粉浓度下的回生淀粉的储存模量随角频率增加而增大;所有样品的损失模量均随角频率升高呈上升趋势。综上,莲子淀粉回生行为受到回生过程中淀粉浓度的影响,并在理化性质上呈现差异。     

Enhancement of Resistant Starch (RS3) in Amylomaize,Barley, Field Pea and Lentil Starches

Native starches isolated from amylomaize. Glacier high amylose barley, field peas and lentils contained 3–5% (w/w) resistant starch (RS3). Retrograded gels that were prepared from these starches had higher RS3 (6–9%) contents. The effects of gel concentration (% starch), storage temperature and time on the RS3 content of the retrograded gels were investigated; the optimum RS3 content was determined in gels prepared at = 10% (w/v) starch concentration and stored under = 20°C for = 5 days. Annealing of the retrograded starch gels by heating and cooling cycles, further enhanced RS3 content to 9–19%; the effect of annealing temperature and number of heat-cool cycles on the RS3 content of the annealed gel were studied. The hydrolysis of retrograded starch gels by pulanase enzyme or acid (2.2 N HCl), prior to annealing, enhanced the RS3 formation during annealing; the enzyme or acid treatment increased RS3 content of the annealed gel to 15–24% or 17–24%, respectively. The potential molecular mechanism that is responsible for the RS3 increase is discussed.     

Effects of Cooking Methods and Starch Structures on Starch Hydrolysis Rates of Rice

This study aimed to understand effects of different cooking methods, including steamed, pilaf, and traditional stir‐fried, on starch hydrolysis rates of rice. Rice grains of 3 varieties, japonica, indica, and waxy, were used for the study. Rice starch was isolated from the grain and characterized. Amylose contents of starches from japonica, indica, and waxy rice were 13.5%, 18.0%, and 0.9%, respectively. The onset gelatinization temperature of indica starch (71.6 °C) was higher than that of the japonica and waxy starch (56.0 and 56.8 °C, respectively). The difference was attributed to longer amylopectin branch chains of the indica starch. Starch hydrolysis rates and resistant starch (RS) contents of the rice varieties differed after they were cooked using different methods. Stir‐fried rice displayed the least starch hydrolysis rate followed by pilaf rice and steamed rice for each rice variety. RS contents of freshly steamed japonica, indica, and waxy rice were 0.7%, 6.6%, and 1.3%, respectively; those of rice pilaf were 12.1%, 13.2%, and 3.4%, respectively; and the stir‐fried rice displayed the largest RS contents of 15.8%, 16.6%, and 12.1%, respectively. Mechanisms of the large RS contents of the stir‐fried rice were studied. With the least starch hydrolysis rate and the largest RS content, stir‐fried rice would be a desirable way of preparing rice for food to reduce postprandial blood glucose and insulin responses and to improve colon health of humans.     

抗性淀粉对糖、脂以及肠道代谢影响的研究进展

综述了近年来国内外对抗性淀粉及其生理功能的研究动态;介绍了抗性淀粉的定义、分类及其生理功能;阐明了抗性淀粉对血糖、血脂及肠道代谢的影响和作用机理。抗性淀粉是一种新型的膳食纤维,在小肠中不被消化吸收, 但在大肠中能被肠道菌群发酵分解。它作为一种低热量、高纤维含量的功能性食品成分,越来越被人们所认识和重视。     

α-淀粉酶水解马铃薯淀粉制备抗性淀粉

以马铃薯淀粉为原料,研究制备RS3型抗性淀粉制备工艺,以抗性淀粉制备产率为考察指标,探讨淀粉浓度、淀粉糊化温度、酶加量、作用时间、作用温度、老化温度和时间等对抗性淀粉产率影响。结果表明,马铃薯回生抗性淀粉最佳制备工艺参数分别为:淀粉乳浓度为10%、高压温度120℃、高压时间30min、α–淀粉酶加入量为120U/mL,淀粉溶液酶解时间30min、pH为6、老化温度4℃、老化时间12h,马铃薯回生抗性淀粉产率达1.126%。     

Effect of Pullulanase Debranching of Sago (Metroxylon sagu) Starch at Subgelatinization Temperature on the Yield of Resistant Starch

The effects of pullulanase debranching of sago (Metroxylon sagu) starch in the granular state and subsequent physical treatments on the formation and yield of type III resistant starch (RS 3) have been investigated. Sago starch was enzymatically debranched with pullulanase at 60°C and at pH 5.0 using different enzyme concentrations (24, 30, 40, 50 PUN/g dry starch) which was added to 20% (w/v) starch slurry and incubated for 0 to 48 h. Optimum enzyme concentration of 40 PUN/g dry starch and three debranching times (8, 16 and 24 h) have been selected for subsequent preparation of RS. Granule morphology and molecular weight distribution (MWD) of the debranched and resistant starch were examined. Debranched starch samples showed blurred birefringence patterns, a decrease in amylopectin fraction, an increase in low molecular weight fraction and a broadening of MWD. Debranched starch samples with a maximum RS yield of 7% were obtained at 8 h debranching time. Temperature cycling and incubation at certain temperature and storage time enhanced the formation of RS. Under the conditions used in this study, the optimum conditions to obtain the highest RS yield (11.6%) were 8 h of debranching time, followed by incubation at 80°C for seven days. The MWD analysis showed that RS consisted of material with relatively low degree of polymerization. This study showed that pullulanase treatment of starch in the granular state resulted in limited debranching of amylopectin but the subsequent physical treatments (incubation time/temperature) can be manipulated to promote crystallization and enhance formation of RS 3.     

超声波辅助酸法制备红薯抗性淀粉及其结构表征

本研究以红薯淀粉为原料,柠檬酸、丙酸、乳酸、盐酸分别为酸解剂,通过超声辅助酸解法制备抗性淀粉。探讨了超声时间、酸的种类和浓度、淀粉乳浓度、酸解时间各因素对抗性淀粉含量的影响。通过扫描电镜(SEM)、差示扫描量热法(DSC)及X-射线衍射(XRD)分析技术对产物进行表征。结果表明,制备抗性淀粉的优化条件为:以质量分数为1%的丙酸溶液酸解质量分数为20%的淀粉乳,依次经过超声处理15 min,恒温振荡4 h,冷冻干燥,其抗性淀粉的含量24.827%。淀粉经超声酸解处理后,其粒径明显增大,形貌由原来表面光滑的多面体颗粒状变为表面有褶皱的片状结构,晶型由A型转变为B型。