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。     

Characteristics and application of octenyl succinic anhydride modified waxy corn starch in sausage

Native and acid‐hydrolyzed wx corn starches were modified by octenyl succinic anhydride (OSA) in aqueous slurry systems. The characteristics of the modified wx corn starches and their effects on chicken meat sausages were evaluated by means of FT‐IR, rapid visco analyser, SEM, and texture profile analysis. FT‐IR spectroscopy indicated that the ester carbonyl groups in the OSA modified native and acid‐hydrolyzed starches were characterized at 1725 cm⁻¹. The process of OSA modification could achieve starch derivatives, which had higher viscosities, better paste clarity and freeze–thaw stability than the native counterparts. Texture results showed that the hardness, springiness, cohesiveness, and chewiness of the sausage increased as OSA‐H0 was added (p < 0.05). SEM revealed that the sausages with native wx corn starch had larger and uneven pores, while it was comparatively compact for the sausages with OSA starches. The OSA modified wx corn starch offered a great potential to be used in meat products to enhance textural quality.     

Structural and rheological properties of potato starch affected by degree of substitution by octenyl succinic anhydride

The objective of the present study was to investigate the structural and rheological properties of octenyl succinic anhydrate (OSA) modified potato starch. Potato starch was modified with different concentrations of OSA (0, 1, 3, and 5%, v/v). X-ray results suggested that OSA modification did not disrupt the crystallinity of the native starch, and esterification occurs primarily in the amorphous regions. The use of ¹H-NMR spectra confirmed the presence of methyl protons in substituted OSA groups, which interacted with the starch molecules. In steady shear rheological analysis, OSA modified starch pastes showed a pronounced shear thinning behavior (n = 0.47–0.54). The consistency index (K) and yield stress (σ_oc) values of OSA modified starch pastes were significantly lower than those of the native starch. Dynamic shear rheological tests indicated that OSA modified starch pastes had weak gel-like behavior with storage moduli (G’) higher than loss moduli (G’’). OSA potato starch pastes were more viscous as compared to the native potato starch paste, as evidenced by their higher tan δ values.     

Preparation and properties of octenyl succinic anhydride modified potato starch

Potato starch was esterified with octenyl succinic anhydride (OSA) in aqueous slurry systems and the major factors affecting the esterification were systematically investigated. The physico-chemical properties of the products were determined by means of Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction and a viscosity analyser (VA). The results indicated that suitable parameters for the preparation of OSA starch from potato in aqueous slurry systems were as follows: concentration of starch slurry, 35% (in proportion to water, w/w), reaction period, 3 h, pH of reaction system, 8.0, reaction temperature, 35 °C, amount of OSA, 3% (in proportion to starch, w/w), OSA dilution-fold, 5. The degree of substitution (DS) was 0.017 and the reaction efficiency (RE) was 72 ± 1.8%. FT-IR spectroscopy showed characteristic absorption of the ester carbonyl groups in the OSA starch at 1724 cm⁻¹. SEM and X-ray diffraction revealed that OSA groups acted by first attacking the surface and some pores formed, but OSA modification caused little change in the crystalline pattern of potato starch (DS 0.045). Apparent pastiness measurement indicated that the starch derivatives gelatinized within a shorter time to achieve higher viscosities over the range of designed concentration of OSA potato starch.     

Preparation and Properties of Octenyl Succinic Anhydride Modified Early Indica Rice Starch

Octenyl succinic anhydride (OSA) modified early indica rice starch was prepared in aqueous slurry systems and the major factors affecting the esterification were investigated systematically. The physicochemical properties of the products were determined by means of Fourier transform infrared (FT‐IR) spectroscopy, scanning electron microscopy (SEM), X‐ray diffraction and Rapid Visco Analyser (RVA). The results indicated that the suitable parameters for the preparation of OSA starch from early indica rice starch in aqueous slurry systems were as follows: concentration of starch slurry 35% (in proportion to water, w/w), reaction period 4 h, pH of reaction system 8.5, reaction temperature 35°C, amount of OSA 3% (in proportion to starch, w/w). The degree of substitution (DS) was 0 018 and the reaction efficiency (RE) was 78%. FT‐IR spectroscopy showed characteristic absorption of the ester carbonyl groups in the OSA starch at 1724 cm^‐1. SEM and X‐ray diffraction revealed that OSA groups acted by first attacking the surface and some pores formed, but OSA modification caused no change in the crystalline pattern of rice starch up to DS 0.046. RVA results indicated that the starch derivatives gelatinized at shorter time to achieve higher viscosities with increased OSA modification.     

Effect of phosphoric acid treatment on physicochemical,functional, and structural properties of starch extracted from yam (Dioscorea rotundata)

This work was designed to elucidate selected physicochemical, functional, and structural properties of native and modified yam (Dioscorea rotundata) starch. The isolated starch was chemically modified using 5, 10, 15, 20, and 25% phosphoric acid solution at 50°C for 1 h, and yield, swelling power, gelation, water holding capacity, paste clarity, blue value, and amylose and amylopectin content of the native and modified yam starch were determined. Structural changes in the native and starch modified with 25% phosphoric acid were evaluated using Fourier transform infrared spectroscopy and optical microscopy. The result showed that the yield, swelling power, water holding capacity, paste clarity, blue value and amylose and amylopectin content of native yam starch was 33.38% (217 g), 3.84 g/g, 1.0 v/g, 10%, 0.52 and 25.96, respectively, whereas gelation study of the native and modified starch indicated that native starch was viscous and modified starch firm. However, yield, swelling power, water holding capacity, paste clarity, blue value, and amylose content of modified yam starch reduced in a dose dependent manner with phosphoric acid. The reduction in the values of the various functional properties could be associated with the effect of phosphoric acid on the starch granular structure. The result of Fourier transform infrared spectroscopy and optical microscopy revealed that the yam starch was modified by phosphoric acid with changes in functional groups spectra such as –OH stretch (3177 cm^?1), H₂O absorbed (1644 cm^?1) (amorphous region), C-H stretch (2923 cm^?1), CH₂O (1253 cm^?1), and C-O-C (1078 cm^?1) when compared to native starch. The morphology of native and modified yam starch granules ranged from oval to eliptical. However, modified starch granules were rough in surface. In conclusion, the characterized physicochemical and functional properties and structure exhibited by native and modified yam starch indicated that, yam could be a cheap and valuable source of starch for industrial application.     

Characterization of Phosphate Monoester Resistant Starch

The properties and structures of corn, wheat, and potato native starches and their phosphate monoester resistant starches were tested and compared. The results indicated that the resistant starch content, light transmittance, and freeze-thaw stability of the phosphate monoester resistant starch increased after modification. The native starches exhibited much higher peak viscosities compared with resistant starch (RS) and phosphate monoester resistant starches. The phosphate monoester resistant starch from corn and wheat starch exhibited a higher peak and final viscosity and lower gelatinization temperatures compared with the resistant starch, while the peak and final viscosity of the potato phosphate monoester resistant starch samples were lower than that of potato resistant starch. In the FT-IR graph, a new peak at 1244 cm^?1 (P=O bond) was observed for all kinds of phosphate monoester resistant starch.     

Study on the morphology,crystalline structure,and thermal properties of Fritillaria ussuriensis Maxim. starch acetates with different degrees of substitution

Fritillaria ussuriensis Maxim. starch acetates with different degrees of substitution (DSs) were prepared by reacting native starch with glacial acetic acid/acetic anhydride using sulfuric acid as catalyst. XRD of acetylated starch revealed that there was loss of crystallinity with increasing DS. The carbonyl group signal at 1750 cm⁻¹ appeared in the FTIR spectra. The intensity of this peak increased whereas the intensity of the hydroxyl groups at 3000–3600 cm⁻¹ decreased. The thermal behavior of the samples was investigated and the results showed that the acetylation decreased the gelatinization temperatures and ΔH_gel, and thermal stability of high DS acetylated starch (DS = 2.82) was much better than that of the original starch and partially substitute starch acetate (DS = 1.52). The SEM suggested that most of the starch granules were disintegrated into many visible fragments along with the increasing of DS. The starch acetate with different DS prepared in this paper has many potential uses in food and pharmaceutical applications for its lower gelatinization temperature and thermal stability properties.     

颗粒状冷水可溶淀粉糊性质的研究

在常压下,用醇解法制备了不同溶解度的颗粒状冷水可溶淀粉系列,并对玉米、木薯和马铃薯原淀粉及其不同溶解度的颗粒状冷水可溶淀粉糊的性质进行了研究。试验证明,相对于原淀粉糊,醇解法制备的颗粒状冷水可溶玉米淀粉糊的表观粘度和冻融稳定性有所提高,凝沉性降低;颗粒状冷水可溶木薯和马铃薯淀粉糊的表观粘度、凝沉性和冻融稳定性均降低。三种颗粒状冷水可溶淀粉糊的透明度大大提高,且随着溶解度提高其透明度增大。     

不同淀粉原料的疏水改性及其性质研究

本文研究了不同添加量的辛烯基琥珀酸酐(OSA)、Al3+以及不同p H值在改性过程中对玉米淀粉、木薯淀粉和马铃薯淀粉休止角、活化指数、接触角、分散性、和偏光特性的影响。实验表明,随着OSA、Al3+添加量和交联过程中p H值的增加,玉米淀粉和木薯淀粉的休止角呈现出先减少后增加的特征,而只有p H值的变化对马铃薯淀粉的休止角产生了比较明显的影响;改性后,三中淀粉的接触角均大于90°,证明淀粉疏水性得到显著提高;同时,在活化指数试验中,木薯淀粉和马铃薯淀粉的活化指数可以达到0.95;液体石蜡中的分散性测试表明,玉米淀粉的分散性最好,其次是木薯淀粉,马铃薯淀粉的分散性最差,而改性后淀粉的分散性较原淀粉并未出现明显变化;最后,通过观察同等光强条件下淀粉的偏光特性,发现改性后淀粉颗粒出现偏光十字变弱、表面阴影增加的情况。     

辛烯基琥珀酸酐改性多孔淀粉结构表征

为提高辛烯基琥珀酸酐(OSA)改性淀粉的取代度(DS),增加其乳化特性和乳化稳定性,以复合酶酶解的多孔淀粉(PS)为主体,OSA为客体,在碱性体系中制备了取代度为0.0191-0.025 9的辛烯基琥珀酸酐多孔淀粉(OSA-PS),并对其结构特性进行研究。SEM结果表明多孔淀粉具有较大的比表面积,可提供更多的反应位点与客体OSA反应,获得更高取代度的OSA改性淀粉(5%OSA-PS为0.025 9);~(13)C NMR和FT-IR表明OSA与多孔淀粉形成了酯键;XRD表明酯化反应并没有改变淀粉的结晶类型,不同OSA水平改性多孔淀粉之间的相对结晶度没有显著性差异;酯化反应降低了样品热降解的初始温度及淀粉的热稳定性。OSA改性多孔淀粉可得到较大的取代度,增加乳化能力和乳化稳定性。     

辛烯基琥珀酸淀粉酯取代度与理化特性关系研究

研究辛烯基琥珀酸淀粉酯的取代度与理化特性的关系对提高其性能具有重要意义。以蜡质玉米淀粉和辛烯基琥珀酸酐为原料制备了系列不同取代度的辛烯基琥珀酸淀粉酯,探讨了制备工艺条件,并用红外考察了特征吸收峰随取代度的变化情况。研究了取代度对辛烯基琥珀酸淀粉酯的乳化和包埋性能的影响,结果显示,乳化能力及乳化稳定性随着取代度的增大呈现出先增加后减小的趋势,包埋率则随着取代度的增大而逐渐提高,但二者总体均比进口产品低。进一步采用XRD和DSC技术对自制和进口产品进行结构分析,结果表明,淀粉的结构也是影响产品的乳化及包埋性能的重要因素之一。     

Synthesis and Preparation of Crosslinked Allylglycidyl Ether‐Modified Starch‐Wood Fibre Composites

Native potato starch has been modified with allylglycidyl ether (AGE) under various reaction conditions including different sodium hydroxide and AGE concentrations, reaction temperatures and times. ¹H‐NMR and FT‐IR were used to analyze the products. AGE‐modified starch, with two degrees of substitution (DS), namely DS = 1.3 and DS = 2.3, was synthesized and used for preparation of a new family of crosslinked composites reinforced with various amounts of bleached softwood fibres. Composite premixes of modified starch, wood fibres and ethylene glycol dimethacrylate (EGDA) were cured in a hot press using 2% (w/w) of benzoyl peroxide at 150°C under high pressure for 10 min. The matrix with high degree of substitution exhibited good processability and was easily processed even for the highest fibre contents, up to 70% (w/w). In addition, scanning electron micrographs showed good dispersion and adhesion between the starch matrix with high degree of substitution and fibre. The original poor mechanical properties of the cured modified starch were markedly improved by the addition of wood fibres. In the extractions tests cured high‐DS and low‐DS composite samples showed weight losses in the range of 1 and 15% (w/w), respectively. No unreacted crosslinker ethylene glycol dimethacrylate was detected in the solutes as determined by NMR.     

疏水改性木薯淀粉的制备及其对肌原纤维蛋白乳化特性的影响

为了提高木薯淀粉的疏水性,使其作为颗粒乳化剂改善肌原纤维蛋白(myofibrillar protein,MP)的乳化特性,实验利用辛烯基琥珀酸酐(octenyl succinate anhydride,OSA)对原料木薯淀粉(native tapioca starch,NTS)进行疏水改性处理,得到不同改性水平和取代度(DS值)的疏水改性木薯淀粉(octenyl succinate tapioca starch,OSTS),并利用OSTS与MP制备复合乳化液。通过XRD、FT-IR、SEM和PLM分析了OSTS的结构变化,并测定了乳化液的乳液指数(EI值)、乳化活性(emulsifying activity index,EAI)、乳化稳定性(emulsion stability index,ESI)、Zeta-电位、粒径分布、巯基含量和界面蛋白含量。结果显示,在木薯淀粉分子中成功引入了疏水基团,疏水改性处理对木薯淀粉颗粒的晶体结构基本无影响;随淀粉改性水平和DS值的增加OSTS-MP复合乳化液的EAI和ESI呈显著增加趋势(P<0.05),3.0%OSTS-MP复合乳化液稳定性最...     

Production and physicochemical properties of 2-octen-1-ylsuccinic derivatives from waxy corn starch

Waxy corn starch was esterified with 2-octen-1-ylsuccinic anhydride (OSA) using response surface methodology. The molecular structure and paste properties were also investigated. Results indicated that the optimum parameters for esterification were as follows: reaction period 4 h, temperature 36.7 °C, pH of reaction system 8.3, concentration of starch slurry 36.9%, and amount of OSA 3%. The degree of substitution was 0.0187 and the reaction efficiency was 80.6%. The ester carbonyl group in OSA starch was characterized by Fourier Transform Infrared Spectroscopy at 1723 cm(-1). Compared with native starch, OSA derivative had higher peak viscosity, better freeze-thaw stability, and decreased gelatinization temperature and digestibility by porcine pancreatic alpha-amylase. Scanning electron microscopy showed that the gels from OSA starch had less and smaller pores; however, the native starch gels changed to sponge-like structure after 4 freezing/thawing cycles. The OSA modified waxy corn starch offered a potential to be used in frozen foods. PRACTICAL APPLICATION: (a) To optimize operating conditions to achieve OSA modified waxy corn starch with a high degree of substitution; (b) to give a deeper insight into the physicochemical properties of OSA modified waxy corn starch, which offered a potential to be used in frozen foods.     

甘薯淀粉辛烯基琥珀酸酯物化性质的研究

以甘薯淀粉为参照,采用扫描电镜分析、红外光谱、差示扫描量热分析、快速粘度分析等现代仪器分析方法对甘薯淀粉辛烯基琥珀酸酯的颗粒形貌、结构特征、热力学特性、黏度特性等物化性质进行了测定和研究。结果表明,甘薯淀粉经辛烯基琥珀酸酐酯化后,其颗粒表面出现不同程度的凹陷和破裂,说明酯化反应发生在淀粉颗粒表面;产品的红外光谱在1718 cm-1和1554 cm-1处出现新的吸收峰,其中1718 cm-1处的吸收峰表明酯羰基的存在,说明分子中引入了新的官能团,1554 cm-1处出现的特征峰是缘于RCOO-不对称的伸缩振动;产品的起始糊化温度、峰值糊化温度、糊化结束温度和糊化热焓值降低,说明淀粉结晶结构的致密程度下降;随着产品取代度的增加,淀粉糊峰值粘度升高,出峰时间提前,糊化温度降低。     

响应面法优化氧化辛烯基琥珀酸甘薯淀粉酯的制备工艺

以氧化甘薯淀粉(oxidation sweet potato starch,OSPS)为原料,制备氧化辛烯基琥珀酸甘薯淀粉酯(octenyl succinate anhydride-oxidation sweet potato starch,OSA-OSPS)。运用响应面分析(response surface method analysis,RSA)辛烯基琥珀酸酐(octenyl succinate anhydride,OSA)添加量、pH值、温度和时间对OSA-OSPS取代度(degree of substitution,DS)的影响,得出最佳制备工艺：酸酐添加量7%、pH8.40、温度40℃,反应时间10h。采用快速黏度分析仪(rapid viscosity analyzer,RVA)分析表明：氧化甘薯淀粉峰值黏度较低,而经过OSA酯化后,峰值黏度又会有一定程度的提高,且随DS的增加呈上升趋势。     

Bread quality of frozen dough substituted with modified tapioca starches

Rheological properties of dough and bread quality of frozen dough-bread containing 18.4% of hydroxypropylated (HTS), acetylated (ATS), and phosphorylated cross-linked (PTS) tapioca starch with different degrees of modification and 1.6% of dried powdered gluten were compared to the same amount of native tapioca starch (NTS) or wheat flour-bread. Doughs substituted with native or modified tapioca starches had the same mixing tolerance as 100% wheat flour. The dough was frozen and stored for 1 week at −18°C, and thawed (one freeze-cycle). The amount of freezable water in the dough substituted with native or modified tapioca starches was not significantly different from that of wheat flour. Frozen dough-bread substituted with highly modified HTS (degree of substitution; DS 0.09–0.11) retarded bread staling, while lowly modified HTS (DS 0.06–0.07) or ATS (DS 0.02–0.04), and PTS (0.004–0.020% phosphoryl content) substitution fastened bread staling as compared with frozen dough-bread baked from wheat flour. The breadcrumbs containing HTS and ATS felt tacky, whereas the bread containing PTS was dry feel. HTS and ATS swelled and collapsed easily during heating, while PTS was difficult to swell and disperse as compared with NTS, therefore the gelatinization properties seemed to affect the texture of bread. Breadcrumb containing HTS showed small firmness during storage, and highly modified HTS-h (DS 0.1) was the smallest. This means highly hydroxypropylated tapioca starch significantly retards bread staling. Staling properties and texture of frozen dough-bread with various tapioca starches were the same as conventional bread baked with the same amount of tapioca starches. These results suggest that a one freeze–thaw cycle and a 1-week frozen period do not change characteristics of starch, gelatinization and retrogradation properties as compared with the conventional method, and the highly modified HTS-h is prominent anti-staling food-stuff in frozen dough.     

酶催化木薯淀粉表面松香酸酯化改性及表征

以木薯淀粉为原料,松香酸为酯化剂,氯仿为溶剂,以液态脂肪酶为催化剂,在两相体系中直接在原木薯淀粉表面进行酯化修饰合成松香淀粉酯(RAS),并利用傅里叶红外光谱(FT-IR)、电子扫描显微镜(SEM)、X-射线衍射(XRD)、热重差分析(TGA)、接触角、乳化能力及乳化稳定性等对RAS的结构及理化性能进行分析。结果表明:与原淀粉相比,FT-IR谱图中RAS在1728 cm-1附近出现羰基特征峰,SEM图中RAS表面的酯化斑点表明木薯淀粉表面成功接上了松香酸基团;XRD和TGA结果显示木薯淀粉经松香酸修饰后结晶度下降;对比原木薯淀粉,RAS(DS=0.0502)的接触角提高了63.40%,乳化能力、乳化稳定性分别由原木薯淀粉的1.53%、1.50%,提高至31.91%、23.08%。且随着DS的升高,RAS疏水性能及乳化性能也随之提高。     

疏水改性藜麦淀粉的制备及其Pickering乳液乳化性研究

本文用碱提法从藜麦种子中提取藜麦淀粉,并用辛烯基琥珀酸酐(Octenyl Succnic Anhydride,OSA)对提取的藜麦淀粉进行疏水改性,得到了辛烯基琥珀酸淀粉酯(OSA淀粉)。通过傅里叶红外光谱、扫描电子显微镜对比原淀粉和OSA淀粉颗粒的结构和形态,发现OSA基团成功接到淀粉表面,在形态上表现为颗粒表面轻度破坏。通过测定乳液微观结构,乳滴粒径及乳化指数(EI),分析了OSA淀粉取代度、颗粒浓度和油相比例等因素对Pickering乳液乳化性的影响。结果表明,乳滴粒径随OSA淀粉取代度或淀粉颗粒浓度的增加而减小、EI值随OSA淀粉取代度或淀粉颗粒浓度的增加而提高,乳液乳化性增强。当油相比例的增加时,乳滴粒径增大,且在食品添加剂允许OSA添加量的范围内,取代度为1.43%的OSA淀粉颗粒的EI值达到最大值75.48%,乳化性最好。研究表明OSA改性藜麦淀粉作为Pickering乳液的稳定颗粒在食品领域有极大的应用潜力。