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.     

高链玉米淀粉-不饱和脂肪酸复合物的体外大肠发酵特性及其对肠道菌群的影响规律

该研究以高直链玉米淀粉（High-Amylose Maize Starch,HAMS）与四种饱和度不同的脂肪酸为原料,制备淀粉-不饱和脂肪酸复合物,研究不同复合物体外大肠发酵特性及菌群调控的影响。结果表明,随着脂肪酸不饱和度的增加,除淀粉-油酸复合物（34.87%）外,形成的复合物V型结晶越少（30.42%~32.93%）。淀粉-不饱和脂肪酸复合物在整个发酵过程中发酵速率无显著性差异（p>0.05）,最终产气量基本一致（13.8~14.2 mL）。淀粉-不饱和脂肪酸复合物产丁酸浓度（14.83~17.91 mmol/L）低于HAMS （22.42 mmol/L）,但产较多乙酸（60.25~63.73 mmol/L）和丙酸（21.22~24.81 mmol/L）。淀粉-不饱和脂肪酸复合物均能显著促进Prevotella的相对丰度,这与其较高的丙酸产量有关。综上,淀粉-不饱和脂肪酸复合物大肠发酵特性受脂肪酸饱和度的影响较小,主要与淀粉-脂质复合物自身结构有关,复合物中脂肪酸的饱和度对高链玉米淀粉-不饱和脂肪酸复合物菌群结构具有一定影响。     

不同酰基改性淀粉结构及热稳定性研究

本文用不同链长酸酐对G50玉米淀粉进行化学改性获得酯化淀粉。利用扫描电子显微镜、傅里叶红外光谱、X-射线衍射仪、小角X-射线散射仪及热失重分析仪表征酯化淀粉的表面形貌、分子结构、结晶结构、有序微区结构以及热性能。结果表明,酸酐碳链越长,取代反应程度越低;酯化淀粉颗粒呈碎片状,丁酸酯淀粉(DS=1.38)和己酸酯淀粉(DS=1.37)易聚集成团;酯化淀粉整体呈现无定型态,高取代度乙酸酯淀粉内部有序微区破坏程度最大,取代度相近时,酸酐碳链越长,对应的酯化淀粉存在周期性长程有序结构;相比于原淀粉,酯化淀粉的热稳定性得到增强,且当酸酐添加量相同时,随着酸酐碳链的增加,酯化淀粉的热稳定性增强程度呈下降趋势。以上结果可为完善酯化淀粉应用提供参考。     

Improving surface functional properties of tofu whey-derived peptides by chemical modification with fatty acids

Effect of acylation with saturated fatty acids on surface functional properties of tofu whey-derived peptides was investigated. Tofu whey (TW) and soy proteins (7S, 11S, and acid-precipitated soy protein [APP]) were hydrolyzed by Protease M 'Amano' G, and resulting peptide mixtures were acylated with esterified fatty acids of different chain length (6C to 18C) to form a covalent linkage between the carboxyl group of fatty acid and the free amino groups of peptide. Acylation significantly (P < 0.05) increased emulsifying properties of 7S, 11S, and APP peptides independent of fatty acid chain length. Acylation decreased water binding capacity although oil binding capacity of acylated tofu whey ultra filtered fraction (UFTW < 3 kDa), 7S- and 11S-peptides were improved compared to native peptides. 7S peptides acylated with long chain fatty acids had shown significant higher surface hydrophobicity as in contrast with acylated UFTW < 3 kDa and APP peptides. Fluorescence spectra studies revealed structural conformation of acylated soy peptides as compared to native peptides. This study shows that chemical modification with fatty acids can further affect functional properties of soy proteins.     

Studying different dimensions of amylose–long chain fatty acid complexes: Molecular, nano and micro level characteristics

Recently amylose inclusion complexes, or V-amylose, have drawn much attention as a possible vehicle for the nanoencapsulation of unsaturated fatty acids. This study aimed to study three different structural strata of V-amylose, the molecular attributes using XRD, DSC and ¹³C CP/MAS NMR and the nanostructures using SAXS. Using these methods it was noted that decreased degree of fatty acid unsaturation induces the formation of more organized and well defined structures. Specifically, calculations based on SAXS data show that regardless of the crystallization temperature saturated SA yields the highest values for parameters like average crystalline lamellar thickness (φ = 0.26) and characteristic particle dimension (R_g = 9.6). SEM shows this trend extends even into the microscopic level. Overall, this study shows that in the case of long chain fatty acids, increased fatty acid unsaturation impairs the structure of amylose inclusion complexes.     

脂肪酸燕麦β-葡聚糖酯结构对其临界自聚集浓度和胶束粒径的影响

采用响应曲面法探讨了脂肪酸燕麦β-葡聚糖酯(fatty acid oatβ-glucan esters,FAOGE)的结构对其临界聚集浓度(critical aggregation concentration,CAC)值和胶束粒径的影响。考察的FAOGE结构参数包括:燕麦β-葡聚糖的分子质量(7.4×10~4~16.8×10~4 D)、取代度(0.010±0.002~0.030±0.002)和酰基链长(6、8、10)。结果表明:不同结构的FAOGE溶液的CAC值在质量浓度为0.050~0.165 mg/m L的范围内,其大小随着取代度、酰基链长的降低或β-葡聚糖分子质量的增加而增加。结构参数对CAC值的影响顺序为:酰基链长取代度燕麦β-葡聚糖分子质量。不同结构的FAOGE自聚集体的平均粒径在264.7~530.9 nm的范围内,且随着取代度、酰基链长的降低及β-葡聚糖分子质量的增加而逐渐增加,结构参数对自聚集体的平均粒径的影响顺序为:取代度酰基链长燕麦β-葡聚糖分子质量。     

New functional fibre in milk puddings: Effect on sensory properties and consumers' acceptability

The effect of the addition of a new functional fibre (high-amylose maize starch, HAMS, as a source of resistant starch), recently available in the market, on sensory characteristics and consumers' acceptability of milk puddings was studied. Milk puddings containing modified waxy maize starch and κ-carrageenan were produced with different HAMS concentrations (0, 1, 2, 3 and 4%). Higher HAMS concentration caused changes in the sensory characteristics of milk puddings. Particularly, sensory attributes such as some roughness, rough afterfeel and floury taste appeared. Besides, the addition of HAMS caused an increase in manual and oral thickness and a decrease in creaminess, melting, and sweetness. A HAMS enrichment level of 1.4% in this product was estimated as the maximum concentration that does not significantly modify consumers' overall acceptability. Using survival analysis the proportion of consumers who would buy milk desserts containing 1.4 % HAMS was estimated as 71%. Consumers more interested in consuming functional foods enriched with fibre were more tolerant to the sensory changes caused by the addition of HAMS to the milk puddings.     

牦牛酥油中鞘磷脂的提取及其脂肪酸组成分析

本研究以牦牛酥油为原料,利用有机溶剂对牦牛酥油中鞘磷脂提取工艺进行探索和优化,并分析鞘磷脂的脂肪酸组成。通过单因素试验与正交试验优化获得鞘磷脂的最佳提取条件为:氯仿甲醇(2:1,V/V)与粗鞘磷脂的液料比为10:1m L/g、浸提温度为40℃和浸提时间为1 h。以提取到的鞘磷脂为原料,采用三氟化硼-甲醇对获得的脂肪酸进行甲酯化处理,用气相色谱串联质谱法(GasChromatography-MassSpectrometer,GC-MS)检测分析鞘磷脂的脂肪酸组成。结果表明,鞘磷脂中含有82.79%饱和脂肪酸、75.70%长链脂肪酸,经过提纯后,鞘磷脂中的多不饱和脂肪酸的含量由原来粗鞘磷脂中的7.98%降低为2.83%,长链脂肪酸含量由85.04%降为了75.70%,超长链脂肪酸由9.57%增加到23.15%,支链脂肪酸由原来的10.43%降为了8.69%,说明鞘磷脂主要由长链脂肪酸和饱和脂肪酸组成。     

气相色谱全分析樱桃谷鸭肥肝脂肪酸

采用Folch 液回流提取樱桃谷鸭肥肝脂质,脂质经氢氧化钾- 三氟化硼法甲酯化后进行气相色谱分析,采用100:1 分流比进样,220～240℃线性程序升温操作,BPX70(60m × 0.25mm ID)石英毛细管柱分离,FID 检测。标准品对照结合线性程序升温等当碳长度(ECLT)值的方法定性了鸭肥肝中11种脂肪酸。面积归一法定量分析了基础日粮添加不同油脂和VE 对樱桃谷鸭肥肝中脂肪酸含量变化的影响。结果表明,基础日粮中按2% 水平分别添加山茶油、芝麻油以及大豆油后,肥肝不饱和脂肪酸含量均明显增加,与对照组比较均呈现极显著性差异(p ＜ 0.01),饱和脂肪酸含量明显下降,与对照组比较均呈现极显著性差异(p ＜ 0.01);基础日粮中按90IU/kg 水平添加VE 后,肥肝不饱和脂肪酸含量增加,与对照组比较差异显著(p ＜ 0.05),饱和脂肪酸含量下降,与对照组比较差异显著(p ＜ 0.05)。     

Characteristics of rennet–casein-based model processed cheese containing maize starch: Rheological properties,meltabilities and microstructures

The rheological properties, meltabilities and microstructural properties of rennet–casein-based model processed cheese slices containing normal maize starch, waxy maize starch and high amylose (70%) maize starch (HAMS) were investigated as a function of the ratio of starch to protein. The storage modulus (G′) increased with increasing ratio of normal maize starch to protein in the processed cheeses, whereas G′ decreased with the addition of waxy maize starch. The tan δ values at high temperature (90 °C) decreased with the addition of both normal maize starch and waxy maize starch, but normal maize starch caused a greater reduction in the tan δ values. These properties were influenced to a lesser extent in processed cheeses containing HAMS. Processed cheeses containing normal maize starch lost meltability at ratios of starch to protein > 0.16; waxy maize starch and HAMS had less influence on the meltability. The effect of starch on the properties of the processed cheeses was attributed to phase behaviours between the protein and the starch, which was shown in confocal laser scanning micrographs.     

Resistant starch prepared from high-amylose maize starch with citric acid hydrolysis and its simulated fermentation in vitro

Resistant starch (RS) was prepared from high-amylose maize starch through two autoclaving–cooling cycles and then acid hydrolysis of retrograded starch. Experimental results showed that hydrolysis of retrograded high-amylose maize starch with 0.1 mol L⁻¹ citric acid at room temperature for 12 h would increase RS yield to 39%. At simulated conditions of large intestine (anaerobic and 37 °C), the prepared RS product was fermented in culture by fresh feces extract from healthy adult or healthy infant to produce short chain fatty acids. Formic, acetic, propionic and butyric acid produced in culture were analyzed by GC with capillary column. The GC analysis results showed that as the increase of fermentation time and the addition level of RS in culture, the production of short chain fatty acids was increased. However, the production of short chain fatty acids (especially butyric acid) in culture fermented by healthy infant feces extract was much higher than that fermented by healthy adult feces extract. It suggested that the production of short chain fatty acids from RS in simulated intestinal conditions might be affected by the intestinal microflora.     

Effect of cryo-milling on starches: Functionality and digestibility

Four commercial starches, potato starch (PS), maize starch (MS), and two high amylose maize starches (HAMS), were cryo-milled, with and without hydration, for 20 min to study the effect of milling on physicochemical properties and enzyme digestibility. There was a significant increase in cold water soluble and damaged starch in cryo-milled samples in the order PS > MS > HAMS. Viscosity parameters of milled starches were significantly lower than for native starches, although changes in pasting temperature were not significant. In vitro digestion of native starches showed that enzyme resistance followed the order PS > HAMS > MS. A significant increase in enzyme digestion rate was observed after cryo-milling PS and HAMS but not MS. However, cryo-milled PS and HAMS were still less rapidly-digested than native MS. Scanning electron microscopy (SEM) of native, milled and digested starches showed a uniform ‘inside-out’ digestion pattern for MS, whereas a heterogeneous and nonspecific pattern was observed for PS and HAMS. This study suggests that milling has predominantly mechanical rather than thermal effects on starches and that the relative enzyme resistance of PS and HAMS granules compared with MS is due to the absence of the structural features of MS granules that allow internal access of enzymes.     

翅果油树种子油的脂肪酸成分分析

采用索氏提取法提取翅果油树种子油,其出油率为32.50%。翅果油树种子油经甲酯化处理后用GC-MS分析和鉴定其组成和相对含量。结果表明,从翅果油树种子油中分离鉴定出11种脂肪酸,其中饱和脂肪酸占8.70%,主要是棕榈酸和硬脂酸;不饱和脂肪酸占91.30%,主要是油酸和亚油酸;并检测出支链脂肪酸和奇数碳脂肪酸12-甲基-肉豆蔻酸和十七烷酸,表明翅果油树种子油是一种值得开发的保健油脂。     

Effects of fatty acid chain length on properties of potato starch–fatty acid complexes under partially gelatinization

A series of starch–fatty acid samples were prepared using potato starch and four fatty acids differing in their chain length, including lauric (C12), myristic (C14), palmitic (C16), and stearic (C18) acids. The results indicated that the fatty-acid chain length played a significant role in altering the properties of potato starch–fatty acid complexes. The complexing index of potato starch–fatty acid complexes decreased from 0.38 to 0.18 with increasing carbon-chain length. V-type crystalline polymorphs were formed between starch and four fatty acids, with shorter chain fatty acids preserving more crystalline structure. X-ray diffraction studies revealed that the degree of crystallinity exhibited by the starch samples was dependent on the fatty-acid chain length. In the Fourier transformed infrared spectrum of the samples, the new spikes at 2917, 2850, 1018, and 720 cm^?1 were assumed to be related to the presence of fatty long chains. The formation of amylose–fatty acid complex inhibited granule swelling of potato starch, w\ith longer chain fatty acids showing greater inhibition. Scanning electron microscopy microscopic examination indicated that amylose–fatty acid interactions taken place during starch gelatinization retarded the destruction of the granules.     

Stereospecific analysis of triacylglycerols in camel (Camelus dromedarius) milk fat

In the lipid fraction of camel (Camelus dromedarius) milk the percentage of saturated fatty acids (SFAs) was 62.8% with a content of palmitic acid of 28.5%. The unsaturated fatty acid (UFA) fraction was dominated by oleic and palmitoleic acids. Enzyme digestion and chemical degradation methods were used to determine the intramolecular fatty acid (FA) composition and then the intermolecular FA distribution in the three sn-positions of the triacylglycerols of the camel milk. FAs showed a specific preference for a particular position: in all samples studied, SFAs were prevalently esterified in the sn-2 position, while UFAs occupied mainly the sn-1 and sn-3 position. As the carbon chain lengthened from 8 to 16 the percentages of SFAs decreased in the sn-2 position and increased in the outer positions. Such data indicated that the length of the carbon chain could be a discriminating factor in the acylation process of SFAs.     

酶促合成肉豆蔻酸淀粉酯的性质及结构表征

为提高淀粉的反应活性,采用氢氧化钠尿素法对马铃薯原淀粉进行处理,以处理后的马铃薯淀粉和肉豆蔻酸为原料,Novozyme 435为催化剂,在无溶剂体系中制备了取代度为0.018~0.065的肉豆蔻酸淀粉酯,并对其部分理化性质进行研究。结果表明:与原淀粉相比,预处理淀粉溶解度和透明度显著增加(P0.05),其膨胀度、冻融稳定性、乳化性和乳化稳定性均显著降低(P0.05)。同时,肉豆蔻酸淀粉酯的性质与其取代度密切相关,与原淀粉相比,随着取代度的增加,酯化淀粉冻融稳定性、乳化性和乳化稳定性随之升高,而其溶解度、膨胀度和透明度随之下降。扫描电子显微镜(SEM)、傅里叶红外光谱分析(FTIR)、疏水性测定对预处理淀粉及不同取代度的肉豆蔻酸淀粉酯进行观察、测定、分析,结果表明,淀粉颗粒结构被破坏,酯化淀粉具有较好的疏水性,FTIR验证了预处理淀粉及酯化淀粉的生成。     

On the participation of fatty alcohols in the autoxidation of lipids

The influence of 1-tetradecanol, 1-hexadecanol, 1-octadecanol and 1-eicosanol in concentrations of 5 to 80 mmol kg^?1 on the autoxidation of various types of lipid systems (sunflower and olive oils, lard, tristearin and olive oil methyl esters) is investigated at 70–135°C. A pro-oxidative effect of the fatty alcohols introduced into the systems is established. The extent of this effect depends on the type and degree of unsaturation in the lipid system, its hydroperoxide content, and the chain length and concentration of the alcohols. A further factor is the valency of the alcohols with which the fatty acids are esterified; thus the pro-oxidative effect of the fatty alcohols is less pronounced with triacyl glycerols than with fatty acid methyl esters given the same oxidation rate. The results obtained are explained on the basis of the theory of a radical chain process of lipid oxidation.     

Effects of fatty acid and emulsifier on the complex formation and in vitro digestibility of gelatinized potato starch

The effects of fatty acid, monoacylglycerol, and polyglycerol fatty acid ester with varying chain length in their acyl chains on the extent of complex formation (complex index) and in vitro enzymatic digestibility of gelatinized potato starch were investigated. The complex index increased with increase in the concentration of the ligands (fatty acid, monoacylglycerol, and polyglycerol fatty acid ester), with the plateau in the complex index value depending on the type of ligands. In comparison of complex index among fatty acid-samples, the complex index maximum increased as the chain length increased up to octanoic acid and then decreased. In comparison of complex index among fatty acid-, monoacylglycerol-, and polyglycerol fatty acid ester-samples at each acyl chain, the complex index maximum followed the order polyglycerol fatty acid ester > monoacylglycerol > fatty acid. Fatty acid, monoacylglycerol, and polyglycerol fatty acid ester with long acyl chains greatly reduced the enzymatic hydrolysis of starch. Polyglycerol fatty acid ester with palmitic acid chains was the strongest inhibitor of starch hydrolysis, suggesting that further complex formation may occur during the hydrolysis of gelatinized starch (enzyme-annealing).     

戊二酸酐酯化κ-卡拉胶的制备及理化性质

以κ-卡拉胶为原料,戊二酸酐为酯化剂,探讨了戊二酸酐酯化卡拉胶（GC）的制备过程中戊二酸酐浓度、反应pH、反应温度、卡拉胶浓度和反应时间对产物取代度的影响,得到制备GC的工艺条件:戊二酸酐浓度4%,反应pH8～8.5,反应温度30 ℃,卡拉胶浓度7.50%,反应时间2 h,取代度为0.077。利用红外光谱、白度仪、粘度仪、扫描电镜和热重分析仪对产物进行表征。结果表明:GC在红外光谱1734 cm?1和在1576 cm?1处峰具有明显的酯羰基和羧基吸收特性,峰值随着取代度的增加更加明显;与原卡拉胶相比,酯化卡拉胶粉末白度略微增加,颗粒表面变得粗糙,表层出现一定凹陷和孔洞,而热稳定性影响不明显;酯化卡拉胶溶液粘度降低,但乳化性及乳化稳定性均得到显著提升（P<0.05）。κ-卡拉胶经戊二酸酐酯化后,改变了其结构与性质,拓宽了κ-卡拉胶的应用范围。     

Medium–Long–Medium and Medium–Long–Long Chain Acyl Glycerols from Beef Tallow and Caprylic Acid

ABSTRACT: Beef tallow was fractionated either without or with solvent to obtain a highly enriched unsaturated fatty acid (USFA) fraction. Solvent fractionation at low temperature (-18 °C) successfully fractionated USFA-enriched triacylglycerol (TAG). The higher that the solute to solvent ratio was used for fractionation, the more weight yield of USFA-enriched TAG from the liquid fractions was recovered during the fractionation. USFA-enriched fraction was further esterified with lipase and medium chain fatty acid (caprylic acid). Through 2nd-step transesterification, MLM (sn-1-medium-2-long-3-mediumTAG) type of structured lipids (SL) was produced in volume. Isolated SL was characterized by reverse-phase HPLC, GC, and DSC. Synthesized SL in this study would be considered as a value-added product from renewable animal fat for nutritionally beneficial applications in food.