碱法制备的4种淀粉-脂肪酸包合物的热力学性质研究

采用差示扫描量热仪、热重分析仪和X-射线衍射仪研究绿豆淀粉、木薯淀粉、甘薯淀粉和马铃薯淀粉对HCl/KOH法制备的淀粉-脂肪酸包合物糊化和热分解性质、玻璃化转变温度(T_g)、结晶结构等的影响。研究表明,淀粉与脂肪酸复合后晶型变为V型。在薯类淀粉-硬脂酸包合物中,马铃薯淀粉-硬脂酸包合物的糊化温度、T_g和热分解稳定性最高,木薯淀粉-硬脂酸包合物的糊化温度、T_g和热分解稳定性最低。在薯类淀粉-油酸包合物中,木薯淀粉-油酸包合物的糊化焓值(?H)最高,热分解稳定性最小;甘薯淀粉-油酸包合物的?H最低,热分解稳定性最大。比较马铃薯淀粉和绿豆淀粉,马铃薯淀粉-硬脂酸包合物的糊化温度、热分解稳定性高于绿豆淀粉-硬脂酸包合物;马铃薯淀粉-油酸包合物的?H和T_g高于绿豆淀粉-油酸包合物。     

湿热处理对大米淀粉理化性质及其米线品质的影响

以大米淀粉为原料,研究湿热处理对大米淀粉理化性质以及米线品质的影响。结果表明:与未处理大米淀粉相比,湿热处理后,大米淀粉的热学特性中T_0、T_P、T_C、T_C_T0、ΔH均增大;淀粉晶型仍为A型,结晶度增加4.14%;淀粉溶解率和膨润力显著降低,直链淀粉含量显著升高;淀粉糊化黏度、衰减值和回生值明显降低;淀粉凝胶硬度、弹性和耐咀嚼性增强;淀粉白度由89.7降低至80.3;添加20%湿热处理大米淀粉制作的米线感官品质和质构特性得到显著改善,断条率和蒸煮损失率分别降低5.67%,10.13%;大米淀粉溶解率、膨润力、溶解率、凝胶特性和糊化特性可有效预测米线品质。     

不同品种马铃薯淀粉微观结构和热力学性质比较

以4个主粮化品种马铃薯淀粉为研究对象,利用激光粒度分析仪、扫描电镜分析仪、差示扫描量热分析仪、X-射线衍射分析仪等仪器分析方法,分析了马铃薯淀粉的微观结构和热力学性质。扫描电镜分析表明,马铃薯淀粉颗粒主要有椭圆形,小球形等形状,不同品种马铃薯淀粉间颗粒形态无明显差异。激光粒度分析表明,4个品种马铃薯淀粉颗粒粒径大小差异显著,粒径平均值为37.43~41.62μm。4个品种马铃薯淀粉颗粒结晶类型相同,均属B型,但它们的相对结晶度有显著差异,且相对结晶度范围为24.87%~29.53%。差示扫描分析表明,4个品种马铃薯淀粉之间的热力学特性参数相变温度(T_0、T_P和T_C)和热焓值(ΔH)有显著差异(p0.05),T0、TP、TC和ΔH范围分别为:58.63~62.25℃,62.92~66.75℃,68.37~73.07℃,13.7235~17.6313 J/g。4个品种马铃薯淀粉的冻融稳定性和透明度也有一定差异。4个品种马铃薯淀粉结构与性质的对比分析结果,为马铃薯主食化原料的筛选提供了理论参考数据。     

三种回生抗性淀粉对米淀粉的冻融与流变性质的影响

研究了添加锥栗、马铃薯与绿豆回生抗性淀粉(RS3)对米淀粉的冻融稳定性与流变学性质的影响。结果表明:添加锥栗、马铃薯与绿豆RS3都能显著提高米淀粉凝胶的持水率,且冻融超过3次后,其影响的差别越来越显著。随着冻融次数增多,米淀粉凝胶中不易流动水明显降低、自由水显著增加;当冻融次数相同时,添加RS3可使米淀粉凝胶中不易流动水明显增多而自由水显著减少。添加锥栗、马铃薯和绿豆RS3后,米淀粉糊的黏性模量明显增加,而弹性模量的增加更加显著。在相同剪切速率下,添加锥栗、马铃薯和绿豆RS3可以使米淀粉糊的抗剪切强度大大增强。添加相同质量浓度的锥栗、马铃薯和绿豆RS3后,米淀粉糊的稠度系数都大大升高、流体指数和滞后环面积显著减小。     

4种抗性淀粉的益生作用及结构变化

采用二次循环压热法制备、纯化得到了绿豆、马铃薯、锥栗和板栗抗性淀粉,并对其益生作用及结构变化进行了研究。结果表明:4种抗性淀粉对双歧杆菌和乳酸杆菌都有较好的增殖作用,对大肠杆菌和产气荚膜梭菌有抑制作用,对粪肠球菌、梭状杆菌、兼性细菌无明显影响。发酵液总酸度增大,表明4种抗性淀粉能被肠道益生菌发酵利用。发酵后抗性淀粉的平均聚合度有所降低,但结构变得更加整齐有序、比表面积增加。发酵后4种抗性淀粉的晶型均变为A型,微晶比例降低。     

锥栗原淀粉及其分离组分的热力学特性

应用差示扫描量热分析仪研究了锥栗原淀粉、直链淀粉、中间成分和支链淀粉的热力学特性。4个样品在-50～350℃的程序升温过程包含冰晶融化(-10～5℃)、糊化(40～100℃)和熔融裂解(250～310℃)3个吸热过程。当水分质量分数为65%时,它们的晶体融化峰值温度(TP)、终止温度(TC)和吸热焓(ΔH)均升至最高。对于相同的样品,当升温速率降低时,糊化温度向低温侧移动,且伴有肩状峰;糊化时升温速率越快,其凝胶体系的峰值温度(TP)、终止温度(TC)和吸热焓(ΔH)也越高,回生度越大;同样,糊化时降温速率越慢,凝胶体系的吸热焓(ΔH)增加,回生度增大。当糊化终止温度为100℃时,4个样品凝胶体系的DSC参数值均达到最低。锥栗原淀粉、直链淀粉、中间成分和支链淀粉凝胶体系的玻璃化转变温度(Tg)分别为-6.0、-7.1、-8.6和-7.9℃。     

银杏抗性淀粉的超声波-酸解法制备及热力学性质分析

以泰州大佛指银杏果为原料,通过超声波-酸解法制备银杏抗性淀粉,以期提高得率,并通过差示扫描量热法(DSC)分析银杏淀粉和银杏抗性淀粉的热力学性质,以探讨银杏抗性淀粉的形成机制。在单因素试验的基础上,采用响应面试验优化得到的银杏抗性淀粉超声波-酸解法制备工艺为:银杏淀粉乳浓度30.6%、HCl浓度1.6%、超声波功率528 W、超声波时间20 min,经验证,该条件下,银杏抗性淀粉得率为(26.45±0.06)%,与预测值的相对误差1%。制备得到的银杏抗性淀粉T_O、T_P、T_C、△H、T_C~T_O均显著高于银杏淀粉,表明了银杏抗性淀粉的制备过程中形成了更牢固的晶体结构,且银杏抗性淀粉结晶体差异程度比银杏淀粉大。     

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。     

微波韧化辅助制备马铃薯抗性淀粉性质的研究

优化马铃薯淀粉制备工艺,采用微波、韧化辅助处理以增加抗性淀粉含量。并对淀粉增抗机制与增抗后淀粉的理化特性进行研究。结果表明,与原淀粉相比,增抗处理后的马铃薯淀粉颗粒表面受到严重侵蚀,相互粘连,呈簇状存在;结晶度比原淀粉显著提高,淀粉分子趋于有序化重新形成的晶体结构;To、Tp、Tc、△H增加,用热处理破坏结晶结构需要更多的能量;淀粉糊的黏度降低,糊化温度提高;抗消化性与抗性淀粉热稳定性增强;吸水性、乳化性与乳化稳定性低于原淀粉,持水能力略微增加。     

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...     

锥栗贮藏保鲜研究

本试验采用不同浓度的抑霉唑浸泡 ( 2 0 0 0ppm、10 0 0ppm、0ppm)、不同温度 ( - 1～ 0℃、5℃、10℃ )等措施 ,对长芒、黄榛、油榛三个品种的锥栗进行保鲜研究。试验结果表明 :用长芒浸泡 2 0 0 0ppm的抑霉唑 ,并在 - 1～ 0℃的低温条件下贮藏 ,锥栗保鲜效果最好     

锥栗直链淀粉-脂肪酸复合物的热特性

以自制锥栗直链淀粉为原料,利用DMSO水溶法分别在60℃和90℃的结晶温度下制备己酸、葵酸、硬脂酸的直链淀粉-脂肪酸复合物,并对其热特性进行了研究。结果表明:与锥栗直链淀粉相比,各种锥栗直链淀粉-脂肪酸复合物的糊化温度与糊化焓、热裂解温度与裂解焓均有不同程度的升高,而其回生焓与回生度、凝固点与玻璃化转变温度却变低,且前者随其复合率的增大而增高,而后者随其复合率的增高而降低。     

板栗壳天然色素对油脂抗氧化作用的研究

以猪油和花生油作为底物,采用烘箱贮藏法测定油脂的 POV值,研究板栗壳天然色素对油脂的抗氧化活性,结 果表明,板栗壳色素具有一定的抗油脂氧化能力,当色素 的添加量分别为猪油和花生油质量的0.03％和0.01％时, 效果最好,而且柠檬酸与抗坏血酸对色素的抗氧化性有 协同增效作用,柠檬酸的协同作用更好,同时添加质量分 数0.005％的柠檬酸和0.03％与0.01％的色素,对猪油和花 生油的抗氧化效果可与0.02％的BHT媲美。     

栗生灰黑孔菌合成漆酶最佳发酵条件的优化

本实验研究了碳源、氮源、诱导剂、金属离子、pH等培养条件对栗生灰黑孔菌Melanoporia castanea (Imazeki)T. Hatt. & Ryvarden产漆酶的影响。并利用Minitab15软件、Plackett-Burman PB 实验设计和响应面分析法对栗生灰黑孔菌Melanoporia castanea (Imazeki)T. Hatt. & Ryvarden产漆酶的发酵条件进行优化。结果表明：1.最佳液态发酵培养基组分为：玉米秆粉9.976g/L,黄豆粉9g/L,ZnSO4•7H2O 0.3µmol /L,对苯二胺0.5mmol/L。2、最佳培养条件：温度28℃,转速180r/min,PH值为5.913,装液量60ml/250ml,接种量10%。在以上条件下培养漆酶酶活可达到431 U/ml。     

板栗壳天然色素的抑菌和清除自由基作用研究

探讨了板栗壳色素粗提物对细菌、酵母菌、霉菌的抑制效果,和对超氧阴离子自由基(O-2.)与羟基自由基(OH.)的清除作用。结果表明,板栗壳色素粗提物对大肠杆菌、枯草芽孢杆菌和青霉菌有一定的抑制作用,最低抑菌浓度分别为2.5%、2.5%和1.5%;对O-2.、OH.也均有一定的清除作用,清除O-2.的能力随色素浓度的增加而增强,但清除OH.的能力与色素浓度无量效关系。     

锥栗直链淀粉-脂肪酸复合物的体外消化及益生元活性

以菊糖与低聚果糖为对照,研究了锥栗直链淀粉与己酸、葵酸、硬脂酸复合物的抗消化作用及益生元效应.试验结果表明:锥栗直链淀粉及其脂肪酸复合物对人工胃液与小肠液都具有不同程度的抗性,其中抗消化作用最强的是分别在60℃和90℃结晶温度下制备的锥栗直链淀粉-脂肪酸复合物(CASC60和CASC90);以两歧双歧杆菌与德氏乳杆菌两株典型的益生菌为研究对象,CASC60和CASC90均表现了良好的益生元活性.因此,CASC60和CASC90具有作为新型益生元开发的潜力.     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.