3种晶型淀粉与月桂酸复合对其抗老化特性的影响

以玉米、马铃薯和锥栗淀粉为原料,探究3种晶型淀粉与月桂酸复合对其短期和长期老化性能的影响.流变结果显示,无论是否与月桂酸复合,3种晶型淀粉糊化后在2 h内均快速老化,但与月桂酸复合后的G'(t)/G'(0)值和tanδ值均显著低于和高于对应的淀粉糊化物(P＜0.05),淀粉短期老化受到抑制;DSC结果表明,3种晶型淀粉...     

韧化处理对3种晶型淀粉消化特性的影响

比较玉米淀粉(A型)、马铃薯淀粉(B型)和锥栗淀粉(C型)韧化处理前后的颗粒形貌、结晶特性和热特性变化,探究韧化处理对3种晶型淀粉消化特性的作用机理。SEM图片显示,韧化处理后玉米淀粉表面出现凹坑,马铃薯淀粉表面出现少许裂痕,锥栗淀粉表面变得光滑,褶皱消失;XRD和FTIR分析表明,3种淀粉经韧化后晶型未有改变,但结晶度均显著提高,分子短程有序性增加,晶体结构更趋稳定;DSC分析表明,韧化处理后3种晶型淀粉的糊化温度显著升高,热焓值无显著变化;韧化处理对不同晶型淀粉消化特性的影响存在差异,3种淀粉经韧化后RS含量均显著增加,水解指数HI和血糖指数GI显著降低;玉米淀粉韧化后RDS含量显著增加,SDS含量显著减少,水解平衡浓度由84.81%降至76.79%;马铃薯淀粉中SDS和RDS含量均显著减少,水解平衡浓度由30.59%降至21.84%;韧化处理对锥栗淀粉的RS、SDS、RDS含量及水解平衡浓度变化影响较小。     

V-型晶种对大米淀粉回生特性的影响

通过在淀粉体系引入脂类构建V-型晶种,将其加入大米淀粉回生体系,并采用X-射线衍射仪、差示扫描量热仪表征晶种晶体特征及其对淀粉回生的影响规律,实现从晶体结构转化的角度解析脂类抗回生的共性机理。研究结果表明,V-型晶种的正交晶胞具有c轴明显长于a、b晶轴的特点。4℃储藏条件下,部分晶种在淀粉体系中起到加速淀粉回生的晶核作用,显著提升淀粉重结晶速率;晶种生长面上的分子链段会影响向其靠近的淀粉分子链段的排列,进而使诱导形成的淀粉晶胞分子链排列更紧密,更趋于V-型晶种晶胞,且晶体生长更快,形成的晶粒更大。这些晶体变化规律的揭示,对淀粉-脂类复合物的抗酶解特性做出新的解释,并为脂类在慢消化类营养功能淀粉创制方面的应用提供重要理论依据。     

配体对淀粉晶型结构的影响

马铃薯淀粉经过酸解处理之后,再用普鲁兰酶进行脱支,滤液冷冻结晶,可得到B型直链微晶淀粉.在B型直链微晶淀粉结晶前加入不同的配体,如脂肪酸、乳化剂、丁醇以及碘等物质进行混合,经X射线衍射分析表明,不同的配体对淀粉的晶型有不同的影响,棕榈酸钠有利于形成淀粉的V型结构.     

大豆蛋白对不同晶型淀粉理化特性的影响

以3种晶型的淀粉即大米淀粉(A型)、马铃薯淀粉(B型)、豌豆淀粉(C型)为原料,探究大豆蛋白对不同晶型淀粉理化特性的影响。采用扫描电镜、傅里叶红外光谱仪、快速黏度分析仪和差示量热扫描仪、模拟体外消化等手段分析处理前、后淀粉的结构、功能及消化特性。结果表明,大豆蛋白对不同晶型的淀粉作用后,O-H伸缩振动的吸收峰向更高方向偏移,T0、Tp的值均增加,糊化温度均升高。与大豆蛋白作用后,大米淀粉的RDS含量下降至37.56%,马铃薯淀粉的RDS含量下降至7.48%,豌豆淀粉的RDS含量下降至9.23%。整体表现为颗粒聚集程度加强,热稳定性提高,结构稳定性增强和消化性降低。不同晶型淀粉间结构的差异性为:A型淀粉表现出结晶区有序性更高,不易老化的特性;B型淀粉表现出更易糊化,消化性降低幅度更大的特性;C型淀粉表现为复合后形成类似“丝状”的结构。上述结果说明,蛋白对不同晶型淀粉作用后对特性的改善起到了作用,且不同晶型淀粉之间的表现存在差异。     

月桂酸对不同直链淀粉含量小麦淀粉黏滞性和质构特性的影响

为了解月桂酸对小麦淀粉黏滞性和质构特性的影响,利用X-射线衍射仪、快速黏度分析仪和质构仪测定月桂酸和3种不同直链淀粉含量小麦淀粉混合体系的晶体结构、黏滞性和质构特性。结果表明:复合指数随月桂酸用量和直链淀粉含量的增加而增大;小麦淀粉的晶体结构为A-型,淀粉和月桂酸复合后出现V-型结构吸收峰,结晶度随复合指数增大而增大;月桂酸显著影响小麦淀粉的黏滞性和质构特性,使小麦淀粉的最终黏度增大,热糊黏度、硬度和咀嚼性减小。1.5%的月桂酸与小麦淀粉复合程度最大,对淀粉黏滞性和质构特性的影响最大。     

压热处理对不同晶型淀粉结构及消化特性的影响

为了探究不同温度的压热处理对3种不同晶型（A型、B型、C型）淀粉颗粒结构和消化特性的影响,将玉米淀粉、马铃薯淀粉和豌豆淀粉在110、120、130℃压热条件下进行处理,并采用XRD、SEM、RVA、DSC和酶解等方式表征不同处理前后淀粉样品的理化性质和消化特性。结果表明,压热处理后淀粉的糊化特性显著改变,峰值黏度、回升值、最终黏度、崩解值降低,糊化温度升高。微观结构分析表明,压热处理过程中的水分和热能会使淀粉颗粒部分糊化,进而导致颗粒表面出现凹陷。压热处理后的马铃薯淀粉逐渐失去B型结晶的特征衍射峰,并显现出A型结晶的特征。与原豌豆淀粉相比,压热处理后的豌豆淀粉晶型有从C型转为A型的趋势,而玉米淀粉的衍射峰没有的明显变化。此外,压热处理后不同晶型淀粉中抗性淀粉的质量分数均显著升高（P<0.05）。作者系统揭示了压热处理后不同晶型淀粉结构及消化特性的变化规律,为后续利用压热法制备具有低消化率的淀粉基食品提供了理论支撑。     

支链聚合度对菠萝蜜支链淀粉与月桂酸复合物理化特性的影响

为探究支链聚合度对支链淀粉-脂肪酸复合物糊化特性的影响,对5种支链聚合度不同的菠萝蜜种子支链淀粉（Jackfruit seed amylopectin, JFSA）与月桂酸复合物（M1ZY、M2ZY、M3ZY、M4ZY和M5ZY）的理化特性进行了测定并分析了这五种复合物糊化特征参数、重均聚合度（DPw）和复合指数（CI）的相关性。结果表明:随着支链聚合度升高,形成的菠萝蜜种子支链淀粉-月桂酸复合物的复合指数显著增加（P<0.05）,由23.27%（M1ZY）提高到35.95%（M5ZY）;五种复合物的脱水收缩程度、水溶性与油溶性,以及膨胀度、溶解度值均明显增加;五种复合物的糊化特征参数值有显著差异,其峰值黏度（PV）、谷值黏度（TV）、最终黏度（FV）随支链聚合度聚合度的增加而升高,但崩解值（BkD）、回生值（StB）降低;Pearson相关分析表明,支链淀粉的DPw与复合物的TV、CI呈显著正相关（r=0.887,0.949,P<0.05）。支链聚合度是影响菠萝蜜种子支链淀粉-月桂酸复合物理化特性的重要因素。     

高直链玉米III型抗性淀粉制备及其结构和特性

以高直链玉米淀粉G50和G70为原料,经酸解、糊化、脱支和重结晶步骤获得III型抗性淀粉,通过退火与压热处理以进一步提升淀粉的抗性比例。采用扫描电子显微镜、X射线衍射、差示扫描量热、快速黏度分析等方法,研究淀粉颗粒形貌、结晶结构、热特性及糊化特性,利用Englyst法测试淀粉消化特性。结果表明：高直链玉米淀粉G50和G70酸解后的得率分别为77.9%和84.5%,重结晶后的得率降为54.4%和70.2%。原G50和G70改性后,淀粉颗粒形貌被破坏,形成大小不等、颗粒形貌不规则的团聚体;淀粉结晶型由B＋V型转变为A＋V型,且结晶度升高;淀粉糊化温度升高,且加热过程中黏度几乎消失。溶解与膨胀特性结果表明,经酸解、糊化、脱支和老化处理后原G50和G70的溶解性显著升高,退火和压热处理后降低了III型抗性淀粉的溶解性和膨胀度。体外消化特性分析表明,改性后的G50和G70具备更强的抗消化性能,抗性淀粉含量最高可达80.5%（G70-RS3-压热20%）。本研究的改性处理能有效提高高直链玉米淀粉G50和G70中抗性淀粉含量,同时抗性淀粉含量与结晶度和糊化温度呈显著正相关。     

月桂酸添加方式对甘薯淀粉及膜性能的影响研究

采用甘油为增塑剂制备淀粉膜,研究了月桂酸添加方式对甘薯淀粉及膜性能的影响。结果表明：对淀粉进行方法 I (加热后添加月桂酸)处理时,直链淀粉-脂质复合物分布在淀粉颗粒表面和内部,而对淀粉进行方法 II (加热前添加月桂酸)处理时,直链淀粉-脂质复合物主要分布在淀粉颗粒表面;方法 I 和方法 II 处理后的淀粉在热分析图中均出现了直链淀粉-脂质复合物的熔融峰;随着月桂酸的加入,淀粉糊各特征点黏度值均出现不同程度的改变;加入月桂酸后,淀粉结晶度降低,在 2θ = 20.15° 处均出现了直链淀粉-脂质复合物的特征衍射峰;加入月桂酸后,淀粉膜表面变得平整,断裂伸长率降低,而抗拉强度和接触角变大;与方法 I 相比,方法 II 更适宜制备淀粉膜。     

Structural characterizations and digestibility of debranched high-amylose maize starch complexed with lauric acid

Structural characterizations and digestibility of debranched high-amylose maize starch complexed with lauric acid (LA) were studied. The cooked starch was debranched by using pullulanase and then complexed. Light microscopy showed that the lipids complexed starches had irregularly-shaped particles with strong birefringence. Gel-permeation chromatograms revealed that amylopectin degraded to smaller molecules during increasing debranching time, and the debranch reaction was completed at 12 h. Debranching pretreatment and prolonged debranching time (from 2 h to 24 h) could improve the formation of starch lipids complex. X-ray diffraction pattern of the amylose–lipid complexes changed from V-type to a mixture of B- and V-type polymorphs and relative crystallinity increased as the debranching time increased from 0 to 24 h. In DSC thermograms, complexes from debranched starch displayed three separated endotherms: the melting of the free lauric acid, starch–lipid complexes and retrograded amylose, respectively. The melting temperature and enthalpy changes of starch–lipid complex were gradually enhanced with the increasing of debranching time. However, no significant enthalpy changes were observed from retrograded amylose during the starch–lipid complex formation. Rapidly digestible starch (RDS) content decreased and resistant starch (RS) content increased with the increasing of debranching time, while the highest slowly digestible starch (SDS) content was founded at less debranching time of 2 h. The crystalline structures with dense aggregation of helices from amylose-LA complex and retrograded amylose could be RS, while SDS mostly consisted of imperfect packing of helices between amylopectin residue and amylose or LA.     

Microstructures of starch granule,starch digestibilities and predicted glycaemic index of common bean mutants in Taiwan

In this study, the microstructure of starch granule and in vitro starch digestibility were compared in de‐coated seeds of common bean variety Hwachia and its NaN₃‐induced mutants. Significant differences in starch granule size (between 17.92 and 27.00 μm), total starch content (between 436.5 and 456.8 mg per seed) and resistant starch content (between 51.6 and 203.3 mg per seed) were found among mutants. Both boiling and autoclaving decreased resistant starch content in processed common beans. Significant difference in predicted gylcaemic index (pGI) (between 48.82 and 64.55%) for processed beans also existed among mutants. However, 96 h of 4 °C storage increased resistant starch content in processed common beans, possibly resulted from starch retrogradation during storage. Mutants SA‐05, SA‐08 and SA‐31, which have smaller seed weight and lower pGI (average of 50.08%) compared to Hwachia (pGI of 57.05%), can be used to produce common bean based low GI dietary carbohydrate.     

脂质与淀粉相互作用及其对淀粉性质影响

淀粉是食品重要成分,在食品体系中起到提供热能与影响质构作用,在蒸煮、焙烤等加热过程中,淀粉粒开始吸水膨胀,淀粉性质发生变化。淀粉中脂质或外加入脂质在淀粉加热过程中,影响淀粉特性变化;脂质存在会使淀粉溶胀性和溶解性降低,改变糊化温度和热焓,对淀粉流变性质也会产生影响。     

三种淀粉载体粉末酱油的性质对比研究

通过真空冷冻干燥技术制备粉末酱油,分别以原淀粉、多孔淀粉和颗粒状冷水可溶性多孔(GCWSM)淀粉作为载体,以淀粉的冷水溶解度、粘度、水解率及柠檬黄吸附量等性质和酱油的氨基态氮含量为评价指标,通过感官评定实验,确定制备粉末酱油的最适载体。使用差示量热扫描仪(DSC)研究粉末酱油制备过程中热力学特性的变化,结果表明:GCWSM淀粉的冷水溶解度和粘度分别为46.79%和205.8mPa·s,水解率和柠檬黄吸附量分别为32.7%和2.417mg/g;GCWSM淀粉制备的粉末酱油的氨基态氮含量达到0.487g/100mL;感官评定表明三种淀粉载体粉末酱油无显著性差异,GCWSM淀粉可以代替原淀粉和多孔淀粉制备粉末酱油;DSC结果显示粉末酱油中的GCWSM淀粉减弱了淀粉本身的糊化特性。      

月桂酸纤维素酯的酰化法制备及其成膜性能

将棉浆粕纤维素溶解在离子液体([Bmim]Cl)中获得纤维素/[Bmim]Cl均相溶液后,在4-二甲氨基吡啶的催化作用下,通过纤维素与月桂酰氯的酰化反应制备了月桂酸纤维素酯(LACE)。采用FT-IR、1H NMR、XRD、TG等表征方法研究了产物结构及热稳定性;考察了产物取代度的影响因素;并选择具有不同取代度的LACE溶解在CHCl3中配成不同浓度的制膜液,采用延流法制膜,通过考察制膜条件与薄膜力学性能的关系以及薄膜形貌特征,研究了LACE的成膜性能。结果表明:95℃下,反应物以物质的量比为n(AGU)∶n(DMAP)∶n(LC)=1∶0.03∶3投料并反应4 h,所得产物具有较高取代度,在非极性溶剂中溶解性能优良,且无需加入增塑剂就可模塑成型。     

Effect of lauric acid and coconut oil on ruminal fermentation, digestion, ammonia losses from manure, and milk fatty acid composition in lactating cows

This experiment (replicated 3 × 3 Latin square design) was conducted to investigate the effects of lauric acid (LA) or coconut oil (CO) on ruminal fermentation, nutrient digestibility, ammonia losses from manure, and milk fatty acid (FA) composition in lactating cows. Treatments consisted of intraruminal doses of 240 g of stearic acid/d (SA; control), 240 g of LA/d, or 530 g of CO/d administered once daily, before feeding. Between periods, cows were inoculated with ruminal contents from donor cows and allowed a 7-d recovery period. Treatment did not affect dry matter intake, milk yield, or milk composition. Ruminal pH was slightly increased by CO compared with the other treatments, whereas LA and CO decreased ruminal ammonia concentration compared with SA. Both LA and CO decreased protozoal counts by 80% or more compared with SA. Methane production rate in the rumen was reduced by CO compared with LA and SA, with no differences between LA and SA. Treatments had no effect on total tract apparent dry matter, organic matter, N, and neutral detergent fiber digestibility coefficients or on cumulative (15 d) in vitro ammonia losses from manure. Compared with SA, LA and CO increased milk fat 12:0, cis-9 12:1, and trans-9 12:1 content and decreased 6:0, 8:0, 10:0, cis-9 10:1, 16:0, 18:0, cis 18:1, total 18:2, 18:3 n-3 and total polyunsaturated FA concentrations. Administration of LA and 14:0 (as CO) in the rumen were apparently transferred into milk fat with a mean efficiency of 18 and 15%, respectively. In conclusion, current data confirmed that LA and CO exhibit strong antiprotozoal activity when dosed intraruminally, an effect that is accompanied by decreases in ammonia concentration and, for CO, lowered methane production. Administration of LA and CO in the rumen also altered milk FA composition.     

Effects of lauric and myristic acids on ruminal fermentation, production, and milk fatty acid composition in lactating dairy cows

The objectives of this experiment were to investigate the effects of lauric (LA) and myristic (MA) acids on ruminal fermentation, production, and milk fatty acid (FA) profile in lactating dairy cows and to identify the FA responsible for the methanogen-suppressing effect of coconut oil. The experiment was conducted as a replicated 3 × 3 Latin square. Six ruminally cannulated cows (95 ± 26.4 DIM) were subjected to the following treatments: 240 g/cow per day each of stearic acid (SA, control), LA, or MA. Experimental periods were 28 d and cows were refaunated between periods. Lauric acid reduced protozoal counts in the rumen by 96%, as well as acetate, total VFA, and microbial N outflow from the rumen, compared with SA and MA. Ruminal methane production was not affected by treatment. Dry matter intake was reduced 35% by LA compared with SA and MA, which resulted in decreased milk yield. Milk fat content also was depressed by LA compared with SA and MA. Treatment had no effect on milk protein content. All treatments increased milk concentration of the respective treatment FA. Concentration of C12:0 was more than doubled by LA, and C14:0 was increased (45%) by MA compared with SA. Concentration of milk FA < C16 was 20% lower for LA than MA. Concentrations of trans 18:1 FA (except trans 12) and CLA isomers were increased by LA compared with SA and MA. Overall, the concentrations of saturated FA in milk fat were reduced, and that of > C16 FA and MUFA were increased, by LA compared with the other treatments. In this study, LA had profound effects on ruminal fermentation, mediated through inhibited microbial populations, and decreased DMI, milk yield, and milk fat content. Despite the significant decrease in protozoal counts, however, LA had no effect on ruminal methane production. Thus, the antimethanogenic effect of coconut oil, observed in related studies, is likely due to total FA application level, the additive effect of LA and MA, or a combination of both. Both LA and MA modified milk FA profile significantly.     

谷氨酸制备马铃薯交联淀粉研究

以谷氨酸作交联剂制备马铃薯交联淀粉,对其制备条件进行研究,考察影响其交联效果因素。结果表明,谷氨酸制备马铃薯交联淀粉工艺条件为:谷氨酸用量5%、pH为8、反应温度45℃、反应时间90 min,在该条件下,制备马铃薯交联淀粉交联度最高。     

Enteric methane production in lactating dairy cows with continuous feeding of essential oils or rotational feeding of essential oils and lauric acid

Rumen microbes can adapt to feed additives, which may make the decrease in enteric CH₄ production upon feeding an additive a transient response only. This study investigated alternate feeding of 2 CH₄ mitigating feed additives with a different mode of action on persistency of lowering CH₄ production compared with feeding a single additive over a period of 10 wk. Four pairs of cows were selected, and within pairs, cows were randomly assigned to either the control (AR-AR) or the alternating (AR-LA) concentrate treatment. The AR concentrate contained a blend of essential oils (Agolin Ruminant, Agolin SA, Bière, Switzerland; 0.17 g/kg of dry matter) and the LA concentrate contained lauric acid (C12:0; 65 g/kg of dry matter). A basal concentrate without Agolin Ruminant and lauric acid was fed during the pretreatment period (2 wk). Thereafter, the cows assigned to the AR-AR treatment received the AR concentrate during all 10 treatment weeks (5 periods of 2 wk each), whereas cows assigned to the AR-LA treatment received AR and LA concentrates rotated on a weekly basis. Methane emission was measured in climate respiration chambers during periods 1, 3, and 5. From period 3 onward, dry matter intake and milk protein concentration were reduced with the AR-LA treatment. Milk fat concentration was not affected, but the proportion of C12:0 in milk fat increased upon feeding C12:0. Molar proportions of acetate and propionate in rumen fluid were lower and higher, respectively, with the AR-LA than with the AR-AR treatment. Methane yield (g/kg of dry matter intake) and intensity (g/kg of fat- and protein-corrected milk yield) were not affected by treatment. Methane yield and intensity were significantly lower (12 and 11%, respectively) in period 1 compared with the pretreatment period, but no significant difference relative to pretreatment period was observed in period 3 (numerically 9 and 7% lower, respectively) and in period 5 (numerically 8 and 4% lower, respectively). Results indicate a transient decrease in CH₄ yield and intensity in time, but no improvement in extent or persistency of the decline in CH₄ due to rotational feeding of essential oils and C12:0 in lactating dairy cows.     

淀粉消化性影响因素及表征方法

介绍了淀粉来源、淀粉中直链淀粉和支链淀粉比例、回生、酶处理、加工处理方式、环糊精、直链淀粉脂质复合物、膳食纤维、蛋白、海藻酸钠等对淀粉消化性的影响及淀粉消化性表征方法。