【作者】 黄兆华；

【导师】 胡秀婷； 李金林；

【作者基本信息】 南昌大学 ， 食品工程（专业学位）， 2021， 硕士

【摘要】 传统塑性脂肪(如饱和脂肪酸与反式脂肪酸)十分不利于人体健康,过多摄入会使体内胆固醇水平增加,导致血栓、动脉硬化等心脑血管慢性疾病,因此迫切需要寻找一种替代传统塑性脂肪的生产加工途径。近年来,油凝胶以其纯物理自组装制备过程及不含反式脂肪酸的特点而备受瞩目。本研究以米糠蜡为凝胶剂制备了油凝胶,并以此为基础,探索了其在油基食品(花生酱)和多重乳液(W/O/W)中的应用,以期代替市场上部分高反式脂肪酸含量的商品或延长商品的货架期。具体研究结果如下:首先,研究了不同制备条件对米糠蜡结晶动力学的影响。重点从米糠蜡添加量、加热温度及结晶温度三方面对凝胶体系微观结构、流变学特性、硬度和热力学行为等方面进行阐述。结果表明,油凝胶体系中的米糠蜡能以结晶方式在液态油脂中形成三维晶体网络,将液体油紧密地束缚在网络结构中。此外,当体系过冷度较低时,RBX晶体趋于一维生长,结晶错配支化发生率较低;过冷度较高时,RBX晶体导致尖端产生支化,形成树状纤维。综合考虑形成凝胶的性能与生产成本,米糠蜡油凝胶的最优制备条件为:米糠蜡添加量为4.0%,加热温度为80℃,结晶温度为25℃。在此条件下制备的米糠蜡油凝胶具有较好的机械性能和热力学性质。其次,研究了米糠蜡对花生酱稳定性的影响。米糠蜡影响花生酱稳定性的本质在于米糠蜡能够形成致密的网络结构从而束缚油滴。以离心出油率和黏度值为指标对花生酱稳定性及质地品质进行表征,采用激光共聚焦显微镜观察其内部结构。离心加速稳定性试验和质构试验表明,稳定型花生酱的最佳制备条件为:米糠蜡的添加量为4.0%,搅拌温度为80℃,冷却温度为20℃。在最佳条件下,花生酱的离心出油率为4.04%,粘度值为165.9 g,花生酱呈棕黄色,有较好的光泽,同时具有浓郁的花生香气,口感细腻。激光共聚焦扫描显微镜照片显示,在较优条件下,固体颗粒在油相中分布均匀。以此条件制备的花生酱在六个月内未发生相分离,酸价及过氧化值在储藏期间无显著变化。最后,研究了米糠蜡对多重乳液稳定性及包埋的原花青素和β-胡萝卜素生物可及性的影响。采用米糠蜡(0%、6.0%、8.0%、10.0%、12.0%)使油相凝胶化以制备结构化W/O/W乳液。通过激光共聚焦扫描显微镜以及酒石酸染色内部水相确认W/O/W乳液的形成。乳液的平均粒径和粘度随米糠蜡浓度的增加而增加。此外,当米糠蜡含量为8.0%或10.0%时乳液稳定性最强。与不含米糠蜡的乳液相比,含米糠蜡的乳液原花青素和β-胡萝卜素具有较高的紫外稳定性、化学稳定性和生物可及性。当米糠蜡添加量为8.0%或10.0%时,原花青素和β-胡萝卜素的化学稳定性和生物可及性均达到最大值。更多还原

【Abstract】 The unhealthy fats(saturated fatty acids and trans fatty acids)in traditional plastic fats are not good for human health.Excessive intake will increase cholesterol levels in the body,leading to chronic diseases such as blood clots,arteriosclerosis and cardiovascular and cerebrovascular diseases.Therefore,it is urgent to find an alternative to traditional plastic fat production and processing methods.The purely physical self-assembly preparation process of the lipid gel and the absence of trans fatty acids attract attention.Due to the single nutrient composition of the lipid product and the instability of the storage period,its application in food is limited.In this study,oil gel was prepared using rice bran wax(RBX)as a gelling agent.Based on this,the application of oleogel in the oil-based foods(peanut butter)and emulsions(W/O/W)was explored to replace some products with high trans fatty acid content on the market.The specific research results were as follows:Firstly,the effects of different preparation conditions on the crystallization kinetics of RBX-based oleogel were studied.The emphasis was on the influence of the rheological properties,microstructure,hardness,and thermodynamic behavior of the oleogel system from the three aspects of RBX addition,heating temperature and crystallization temperature.The results showed that the RBX could form a threedimensional crystal network in the liquid oil,and the liquid oil was tightly bound in the network structure,thus forming the oleogel.Considering the performance and production cost of the oleogel,the optimal preparation conditions of the RBX-based oleogel were as follows: the addition amount of RBX at 4.0%,the heating temperature at 80 °C,and the crystallization temperature at 25 °C.The RBX-based oleogel prepared under these conditions has good mechanical properties.Secondly,the effect of RBX on the stability of peanut butter was studied.The essence of RBX affecting the stability of the system was that the network structure formed by the system with a large amount of RBX was denser,which restrained more oil droplets.Oil loss and viscosity were used as indicators to characterize its stability and texture quality,and its internal structure was observed with a laser confocal microscope.Centrifugal acceleration stability test and texture test showed that the best preparation conditions were as follows: the addition amount of RBX at 4.0%,the stirring temperature at 80 °C,and the cooling temperature at 20 °C.Under the best conditions,the oil loss was 4.04% and the viscosity was 165.9 g.The laser confocal scanning microscopy analysis showed the solid particles were evenly distributed in the oil phase under better conditions.Phase separation did not occur to the peanut butter prepared under this condition within six months,and the acid value and peroxide value remained unchanged during storage.Finally,the effect of RBX on the stability of multiple emulsions and the bioavailability of the delivered proanthocyanidins and β-carotene was studied.W/O/W emulsions were easily prepared by oleogelation of the oil phase using RBX(6.0%,8.0%,10.0%,and 12.0%)and their microstructure,stability,rheology and protection of proanthocyanidins and β-carotene were investigated.Formation of the W/O/W emulsion was confirmed by confocal laser scanning microscopy and staining of the inner aqueous phase by tartrazine.The average particle size and viscosity of the emulsion increased as the RBX concentration increased.RBX increased the stability of the emulsion and the emulsion was the most stable after addition of 8.0% or 10.0%RBX.Compared with the emulsion without RBX,RBX-containing emulsions performed better in simultaneously encapsulating proanthocyanidins and β-carotene.Specifically,proanthocyanidins and β-carotene in RBX-containing emulsions had higher stability and bioaccessibility,and both their chemical stability and bioaccessibility reached the maximum value with addition of 8.0% or 10.0% RBX.更多还原