【作者】 石燕；

【导师】 郑为完；

【作者基本信息】 南昌大学 ， 食品科学， 2008， 博士

【摘要】 本文深入开展了土制酥油的精制及综合利用研究,充分利用土制酥油中蛋白、香气物质,建立了一套完整的新的生产工艺,避免了传统工艺产生的废弃物如蛋白等对环境的污染。建立了牛油单甘酯—二乙酰酒石酸单双甘酯—酪朊酸钠的西藏酥油微胶囊化乳化体系,该体系制备的酥油乳状液稳定,喷雾干燥过程中不转型(0/w→w/0型)破乳,在高浓度(5%)食盐和高浓度茶汁(含1%红茶提取物)的情况下,也无任何破乳现象。针对传统的粉末油脂生产使用的麦芽糊精(或玉米糖浆)壁材,在喷雾干燥时由于水分的快速蒸发会造成空洞、裂缝的现象进行了研究,提出了在麦芽糊精(或玉米糖浆)中添加自修复剂的设想,并研究筛选复配了三种增塑剂(三种自修复剂),对它们的性质、性能、用量等进行了初步研究,使其在西藏酥油粉的研制中得到应用。对西藏酥油微胶囊化工艺进行了研究和优化,得出了酥油乳状液制备的温度为70～75℃,均质压力为35～40MPa,喷雾干燥的进风温度160～190℃,出风温度90～100℃的最佳参数。对酥油微胶囊品质研究结果表明:产品表面油含量低(1.52%)、包埋率高(96.6%),粉末细腻、均匀,颜色为乳白色,气味纯正,带有酥油的香气,无异味。测定200天贮藏期间酥油及其酥油微胶囊产品的过氧化值和酸价变化实验发现:酥油在考察的200天时间内,过氧化值经历了上升到下降的过程,发生了酸败,产生了哈喇味;而经过了微胶囊化的酥油粉末在考察的200天时间内,过氧化值变化很小,仅有微弱上升;酥油的酸价在考察的200天时间内上升了19.21个单位,而酥油微胶囊产品酸价只上升了5.30个单位。说明所研制的酥油微胶囊成膜材料性能好,能有效的保护芯材酥油,阻止其与空气中的氧气、水等接触,酥油微胶囊产品耐贮藏,保质期长。对酥油及其酥油微胶囊营养成分进行了分析研究,结果表明:酥油及其酥油微胶囊营养丰富。采用酥油顶空进样、酥油直接进样和用水蒸气蒸馏提取酥油香气成分三种方法,通过气相色谱-质谱联用技术对西藏酥油中挥发性香气成分进行分离、鉴定,共鉴定出52种化学成分。采用红外光谱法研究了微胶囊壁结构形成过程中蛋白质与碳水化合物的相互作用,结果表明:蛋白质分子与周围介质糊精的羟基发生了缔合作用,有利于维持微胶囊结构的完整性;酥油微胶囊化后,酥油红外特征峰未发生变化,说明酥油微胶囊化后对芯材酥油的影响不大,即微胶囊化后的酥油基本保持了原有的特征风味。选择异硫氰酸荧光素作为荧光探针,在碱性条件下标记酪蛋白,采用紫外光谱法和荧光光谱法研究了标记前后酪蛋白和异硫氰酸荧光素相互作用的光谱变化情况,并采用激光扫描共聚焦显微镜对荧光标记酪蛋白作乳化剂制备的酥油微胶囊进行断层扫描,结果表明:异硫氰酸荧光素是一种非常理想的荧光探针;在芯材和壁材界面以及微胶囊表面有绿色荧光出现,说明了酪蛋白是在油水界面膜和微胶囊表面聚结。用扫描电镜和激光共聚焦扫描显微镜对酥油微胶囊表观形态分析结果表明,微胶囊表面光滑,没有皱摺、凹痕、空洞和裂缝,微胶囊壁表面完整,壁结构较为致密。同时,激光共聚焦扫描显微镜断层扫描得到微胶囊酥油内部超微结构,结果表明微胶囊存在单核和多核两种形式。原子力显微镜测定结果表明,酥油微胶囊颗粒表面粗糙度为7.651～8.693 nm。采用乳化—溶剂扩散技术制备了酥油-PLGA纳米胶囊,纳米胶囊平均(团聚)粒径为0.20μm,一次粒径为77～100 nm。增大酥油的浓度有利于提高芯材油脂含量;PLGA的浓度增加导致聚合物胶囊粒径增大,聚合物浓度的增加导致胶囊粒径增大。在保证酥油包埋率的前提下,尽可能的增大油相的比例,以获得较小粒径的纳米胶囊。大的内水相,可导致酥油有更多机会扩散出内乳剂,减少酥油的包埋率。随着水量的增大,胶囊的粒度也增大。红外光谱研究表明,PLGA的C=0基团的氧原子分别与酥油的羧基、聚乙烯醇侧基上羟基形成了氢键(0…H),使PLGA的C=0伸缩振动吸收峰发生位移。酥油主要被包裹在纳米胶囊的内核心部位形成壳层结构。对于纳米胶囊主要是形成反胶团,在反胶团的内核中存在着至少三种状态的水,即结合水、自由水和游离水,而且其所占的比重会随着反应参数的改变而改变。更多还原

【Abstract】 The paper has carried out the native ghee purification and its comprehensive utilization research completely.In this article,a new technics was founded using the protein and fragrance material of the native ghee fully in order to avoid the environment pollution caused by the waste which is produced in the traditional technics process.At the same time,we deeply studied butter monoglyceride - diaceltyl tartaric acid ester of monodiglyceride(DATEM)-casin Tibet ghee microcapsule emulsified system and found that the emulsified liquid prepared by this system was stable,and there was no reformation(O/W→W/O)in the spray-drying process,and had no emulsion breaking phenomenon even in the high concentration common-salt(5%)and high consistency tea juice(including 1%substance distilled from black tea).Because of the reason why the malt dextrin(or corn syrup)wall material used to produce the traditional pulverous grease could cause cavities and cracks phenomenon when spray-drying,we refered a assumption of appending sele-reparing substances in the malt dextrin(or corn syrup).What’s more,three samples were made already,and it is hopeful that they will be used in the manufacture of Tibet ghee powder after we gave them a elementary research including their character,performance,dosage and so on.By researching and optimizating Tibet ghee microencapsul technology,we knew the appropriatest parameters such as the temperature of ghee emulsion (70-75℃),the homogeneous pressure(35～40Mpa),the temperature of entering wind(160-190℃)and emerging wind(90-100℃)in the spray- drying process.we also investigated the ghee’granularity by Laser particle analysis.By investigating the ghee microcapsules’ quality,the results showed that:the oil amount on the surface was in low(1.52%),but had a high rate of embedded(96.6 percent),the powder was exquisite and uniform,its color was ivory,the smell was pure,with a little ghee’s aroma.During 200 days storage time the changes of peroxide value and acid about the ghee and the ghee microcapsule products showed that:the peroxide value in the 200 days was from rosing to dropping and rancidity had happened and had la taste.But ghee powder which dealed with microcapsule had little rise during those days.The truth which acid value of ghee rose 19.21 units and the ghee microcapsule product only rose 5.30 units indicated that ghee microcapsules had a long life because the propertie of microcapsules’ film material was so good that they can protect the core material of ghee effectively for stopping contacting with the oxygen,water and others in the air.Elements analysis had been conducted and it was not difficult to find the nutrient contents in the ghee and the ghee microcapsule were abundant.Several ways were adopted to detect the elements including in the perfume which volatilizezing form ghee and the results showed there wre 52 kinds of compounds in it.These detecting methods were headspace sample,ghee direct sample and using the steam to distill the ghee fragrance and then united them with gas chromatography-mass spectrum.By using the infrared spectrometry to investigate the interaction between protein and carbohydrate in the process of forming the micro capsule wall structure, it finally indicated:the association function exists between the protein molecule and the environmental dextrin’s hydroxyl,which is goog for maintaining the integrity of the microcapsule structure;but as to mcro-encapsuled ghee,the infrared characterful peaks did not change,which showed that it had little effect on the core material,for another word,its primary features were maintained.We choosed isothiocyanate-fluorescein as a fluorescent probe,and used it to mark casein protein in alkaline conditions,and used UV and fluorescence spectrometry to study the spectrum changes of interactions between the casein protein which is marked or not marked and fluorescein isothiocyanate,And adopted a confocal laser scanning microscope to scan the ghee microcapsules which was marked,the results showed that:the probe was a very good one.Green fluorescence is found between the core material and the wall material and the microcapsule surface,so we could conclude that the casein protein assembled in the membrane surface of oil-water interface and micro-capsules.Using the scanning electron microscope and confocal laser scanning microscope,we could get the ghee microcapsule apparent morphological analysis result,which indicates the microcapsule surface is smooth,dent,cavity, intact,crack,and had no corrugation,and the wall structure was compact.At the same time,the microcapsule ghee interior ultra structure which had two forms,namely single nucleus and the polynuclear which could be detected through confocal laser scanning microscope.Through atomic force microscope determination we got the ghee microcapsule’s roughness was 7.651-8.693 nm.By using emulsion-solvent-difusion to preparate ghee-PLGA nano-capsules,the average particle diameter was 0.20μm,the first diameter was 77-100 nm.Increasing the ghee’s amout was good to raising oil content of core material;Increasing the PLGA’s amout and the concentration of polymer led to bigger capsule size.Under the premise of guaranteeing the ghee embedding rate,we try our best to increase the proportion of the oil phase in order to obtain smaller particle size.Bigger domestic water phase may lead to the ghee diffuse from inter- emulsification,and then embedding rate was reduced.Along with the enlargement of the water volume,the capsule granularity would increase.The infrared spectrum of PLGA analysis indicated that oxygen atom in the C=O groups formed hydrogen bond with the carboxyl ghee and polyvinyl alcohol of the side-hydroxy to make PLGA’s C=O stretching vibration absorption displaced.The ghee which was mainly wrapped in the nanometer capsule to form shell structure. The nano-capsules was mainly to form anti-micelles and there were at least three kinds of water in them,such as bounding water,free water and free moisture, moreover,the proportion of them would change along with the reaction parameter changing.更多还原