植物蜡及液态植物油构建油凝胶的物性研究

以米糠蜡、棕榈蜡、蜂蜡3种食品级植物蜡为凝胶剂,葵花籽油、油茶籽油、亚麻籽油、棉籽油为基料油,构建了植物油基油凝胶,系统分析了油凝胶的外观形态、持油能力、微观结构、硬度、晶型及熔化结晶行为。结果发现,棕榈蜡基油凝胶涂抹性能优良,蜂蜡基油凝胶在三者中具有最高的持油能力。微观分析表明,米糠蜡形成的油凝胶晶体结构较为清晰,呈细长的针状;蜂蜡形成的油凝胶晶体结构最为细小,呈细小的针状;棕榈蜡形成的油凝胶,针型细密,并呈絮状结晶。晶体密度及样品硬度均随凝胶剂质量分数增加而增加。油凝胶的晶型与凝胶剂质量分数、基料油的种类无太大关系,主要取决于凝胶剂的种类。熔化结晶行为表明,凝胶剂种类相同时,随着其质量分数的增加,油凝胶的结晶/熔化峰值温度均升高。     

高熔点脂肪对凝胶油基人造奶油品质的影响

以全氢化棕榈油作为高熔点脂肪源,将0.5%～2.5%的全氢化棕榈油与葵花油混合作为基料油,制备凝胶油基人造奶油。探究高熔点脂肪对凝胶油基人造奶油的脂肪酸组成、稳定性、熔点、质构、流变性质、微观结构和晶型的影响。结果表明,当高熔点脂肪添加量低于1.5%时,人造奶油的熔点过低、可塑性较差;而添加量高于1.5%时,人造奶油的不稳定指数值大于1.5,体系劣变严重;添加量为1.5%时,硬度、可塑性和黏度均更接近于市售人造奶油,综合表现最佳。     

乙基纤维素对油脂流变性质和凝胶特性的影响

将不同黏度和质量分数的乙基纤维素(EC)添加到大豆油中,研究EC凝胶剂在油相中的流变性能、凝胶网络结构稳定性、硬度和液态油脂损失率。结果显示,EC油相溶液属于假塑性流体,当EC黏度为7~100 m Pa·s,溶液表观黏度呈现增大趋势,当EC黏度为200 m Pa·s时,溶液表观黏度下降;随着EC质量分数增加,溶液表观黏度逐渐增大,并出现凝胶化。其中,当EC质量分数为8%时,EC100凝胶网络对振荡频率的稳定性最好。质构分析显示,凝胶硬度的变化趋势与其网络结构稳定性相一致,EC100凝胶的硬度达到最大175.94 g,同时EC100凝胶的油相损失率最低,仅为3.14%,表明稳定的凝胶网络结构有利于更好地截留液态油。     

蜡添加量对巴西棕榈蜡-油茶籽油凝胶物性、氧化稳定性及消化特性的影响

以油茶籽油为基料油,巴西棕榈蜡为凝胶剂制备巴西棕榈蜡-油茶籽油凝胶,探讨不同蜡添加量对其外观形态、持油率、硬度、晶型、热力学性质、氧化稳定性以及消化特性的影响。结果表明：蜡添加量为5%时才能使油茶籽油凝胶化,凝胶的硬度、持油率以及结晶/熔融峰值温度总体随着蜡添加量的增加而增大;凝胶的网络结构能够抑制油茶籽油次级氧化产物生成,提高油茶籽油的氧化稳定性;蜡添加量越高的凝胶脂肪酸释放率越低。     

基于蜂蜡油凝胶的植物奶油制备与性质表征

考察影响蜂蜡油凝胶和基于蜂蜡油凝胶的植物奶油的理化性质的关键因素。以玉米油为油相,蜂蜡为凝胶剂,添加不同的小分子乳化剂（失水山梨醇脂肪酸酯、卵磷脂）制成油凝胶;油凝胶与水混合,通过乳化法制得植物奶油。理化性质表征发现,蜂蜡-卵磷脂油凝胶和蜂蜡-司盘40油凝胶的持油力均能达95%以上,持油效果较好;而乳化剂的质量分数和贮藏温度均会对油凝胶的硬度产生影响：乳化剂质量分数越高,贮藏温度越低,油凝胶的硬度越低;综合考虑蜂蜡油凝胶的质构特性以及持油力,冷藏条件下,乳化剂质量分数为1%的蜂蜡油凝胶综合性能较好。同时,乳化剂的质量分数和贮藏温度也会对植物奶油的流变特性产生影响：乳化剂质量分数越高,贮藏温度越低,植物奶油的黏弹性和稳定性越好;乳化剂的加入还可以大大改善植物奶油的持水力;整体而言,冷藏条件下,乳化剂质量分数为2%的植物奶油综合性能较好。本课题制备的植物奶油具有成为黄油及奶油替代品的潜力,可以为消费者提供更加健康的食品原料。     

基于植物甾醇与γ-谷维素的牡丹/葵花籽油凝胶的制备及其物理特性研究

凝胶剂的含量和比例、植物油基质是影响油凝胶结晶特性和加工功能的重要因素。该研究以植物甾醇和γ-谷维素为凝胶剂,牡丹籽油和葵花籽油为基质油制备高含量α-亚麻酸油凝胶,探讨了植物甾醇与γ-谷维素的质量比以及基质油对油凝胶外观、硬度、黏度、微观结构、流变和热力学性质的影响。结果表明,在4℃下,当m(植物甾醇)∶m(γ-谷维素)=40∶60,添加量为8%(质量分数)时,油凝胶形成的速度最快,硬度和黏度最大,熔点也最高;与葵花籽油凝胶相比,此条件下牡丹籽油凝胶的硬度更大(210.70 N),凝胶时间更短(0.5 h),熔点更高(55.22℃)。油凝胶制备时,可通过调整植物甾醇与γ-谷维素的比例来获得所需的晶型和凝胶网络结构,并由此获得理想的硬度、黏度、熔点和透明度等,以适应特定食品加工的需求。该研究为后续基于油凝胶的新型功能黄油和功能奶油的制备提供了理论基础。     

小麦醇溶蛋白/卵磷脂复合纳米粒子制备Pickering乳液研究

以小麦醇溶蛋白和卵磷脂为原料,利用pH循环法制备小麦醇溶蛋白/卵磷脂复合纳米粒子,并以此为稳定剂制备Pickering乳液。探究了纳米粒子质量分数、油相体积分数对Pickering乳液的粒径、微观形貌、乳析稳定性、储藏稳定性及流变学特性的影响。结果表明：制备的Pickering乳液为水包油型乳液。当小麦醇溶蛋白/卵磷脂质量比为2∶1时,Pickering乳液的乳化活性和乳化稳定性分别为9.33 m²/g和93.33%。固定油相体积分数为50%,当纳米粒子质量分数由0.1%增加到2.0%时,Pickering乳液的粒径由56.19μm减小到36.57μm,乳析指数由46.5%增加到91.0%;固定纳米粒子质量分数为1.5%,当油相体积分数由20%增加到60%时,Pickering乳液的粒径由31.43μm增大到38.79μm,乳析指数由54%增加到93%。流变学结果表明,乳液的表观黏度和弹性性能随着纳米粒子质量分数以及油相体积分数的增加而增加,且都具有剪切稀化的现象,形成了凝胶网络结构;环境应力稳定性实验表明,Pickering乳液具有良好的NaCl离子稳定性。     

花生蛋白-果胶复合乳液凝胶的流变学特性和微观结构

研究不同油相及其添加量对转谷氨酰胺酶诱导制备的花生蛋白-果胶复合乳液凝胶质地特性的影响规律,同时通过流变学和微观结构特性研究探索乳液凝胶的形成机理。结果表明：花生蛋白-果胶复合乳液凝胶的凝胶强度显著高于水凝胶。凝胶外观和储能模量（G’）结果表明油滴与蛋白-果胶组成的凝胶基质相互作用,从而影响乳液凝胶的质地和凝胶强度。油相添加量的增加可以使乳液凝胶的力学性能增强,网络结构更稳定。花生蛋白-果胶复合乳液凝胶的G’值和硬度随油相添加量的增加而增大,说明分散的油滴作为活性填料与凝胶基质相互作用。花生蛋白-果胶复合乳液凝胶的微观结构结果表明,油相添加量60%(V/V)时24度棕榈油为油相的乳液凝胶网络结构更致密。研究结果为花生蛋白-果胶复合乳液凝胶在食品领域的开发利用提供思路。     

米糠蜡添加量对亚麻籽油基油凝胶结构及性质的影响

为探究亚麻籽油基油凝胶作为替代传统塑性脂肪的潜力,以米糠蜡为凝胶剂,探究不同米糠蜡添加量对亚麻籽油基油凝胶外观形态、微观结构、持油率、理化性质及热力学性质的影响。结果表明：在室温条件下,米糠蜡添加量不小于6%时才会使亚麻籽油凝胶化;随着米糠蜡添加量的增加,油凝胶的结晶网络结构由簇状逐渐转变为针状,结晶密度增大;油凝胶的持油率、酸值以及熔融峰/结晶峰峰值温度均随着米糠蜡添加量的增加而增大;油凝胶的过氧化值随着米糠蜡添加量的增加呈现先增后减的趋势。综上,在亚麻籽油中添加适量的米糠蜡可形成热塑性好、结构稳定、理化性质良好、持油率高的油凝胶。     

酪蛋白与乳清蛋白比例对酸奶凝胶性质的影响

研究了乳中酪蛋白和乳清蛋白比例对凝固型酸奶流变学特性和微观结构的影响,结果表明,固定蛋白质质量分数、降低酪蛋白和乳清蛋白的比例,可以明显提高酸奶凝胶的质量.乳中蛋白质质量分数一致时,酸奶凝胶的硬度、黏度、持水力随着酪蛋白和乳清蛋白比例的减小而增大,凝胶网络结构变得更规则、致密,孔隙更小.在低蛋白质质量分数下,降低乳中酪...     

Development of Novel Low-Molecular-Mass Oil-gelling Agents: Synthesis and Physical Properties of 1,5-Anhydro-D-glucitol and 1,5-Anhydro-D-mannitol Protected with Saturated Linear Fatty Acids

We have developed a novel low-molecular-mass oil-gelling agent that is electrically neutral, has no nitrogen atoms and consists only of cyclic sugar alcohols and saturated linear fatty acids. The cyclic sugar alcohols were 1,5-anhydro-D-glucitol (1,5-AG) and 1,5-anhydro-D-mannitol (1,5-AM) derived from starch via 1,5-anhydro-D-fructose. Various saturated linear fatty acids with 10 to 18 and 22 carbon atoms were introduced into all the hydroxy groups of 1,5-AG. Various saturated linear fatty acids with 13 to 18 and 22 carbon atoms were introduced into all the hydroxy groups of 1,5-AM. Initially, the gelling ability increased as the carbon number increased, but the gelling ability decreased as the carbon number increased beyond 17 carbons. This trend was similar for both 1,5-AG and 1,5-AM. A comparison of 1,5-AG and 1,5-AM derivatives revealed that 1,5-AG derivatives had greater gelling abilities for different kinds of oils at the same fatty acid length. Further, it was confirmed by SEM observations that a three-dimensional fibrous structure was formed, and this network structure formed the gel and held the oil. Here, we report the synthesis and characteristics of a novel low-molecular-weight gelling agent and its gelation mechanism.     

Fatty Acid Composition and Triglyceride Structure of Corn Oil, Hydrogenated Corn Oil, and Corn Oil Margarine

Corn oil, hydrogenated corn oil and corn oil margarine were compared on the basis of fatty acid composition and triglyceride structure, including configurational isomerism of unsaturated fatty acids. Hydrogenated corn oil contained trans unsaturation and positional isomers not naturally found in corn oil. The β-position of triglycerides of hydrogenated corn oil was 85% occupied by trans octadecenoic acids (trans-18:1); that of corn oil was 70% occupied by linoleic acid. The proportion of cis octadecenoic acids (cis-18:1) in the β-position of the triglycerides was distinctly less in the hydrogenated corn oil than in corn oil, indicating a hydrogenation and/or a geometrical isomerization of cis-18:1 to trans-18:1 preferentially in the β-position, as compared with the α-positions. Chemical composition of corn oil margarine was intermediate between that of corn oil and that of hydrogenated corn oil.     

Evolution of some physicochemical parameters of iodine fortified sunflower oil and margarine

Experimental research were effectuated to establish the modalities of incorporation of the molecular iodine in sunflower oil double refined and deodorised of autochthon production. It was established that the iodisation of sunflower oil may be considered as an admissible method, which allows the incorporation of a considerable amount of iodine (1–100 μg mL^?1) without modifying the physicochemical properties of the product. It should be noted that iodine value varied a little, even in the sample with a maximum content of iodine (1000 μg mL^?1), its values did not exceed permitted limit. Research of quality indices variation of iodised oil during product storage (3 months), demonstrated that only in the case of maximum concentration of iodine (1000 μg mL^?1) it was manifested a slight overcome of the maximum permitted limit caused by the free iodine presence. Iodised oil was used for the manufacture of iodised margarine in order to fortificate this product with iodine (1 μg iodine g^?1 margarine). Physicochemical indices (moisture and volatile substances, melting point, free fatty acids content) of iodised margarine did not differ from the characteristics of the product without iodine.     

Alteration of fatty acid composition, tocopherol content and peroxide value in margarine during storage at various temperatures

Changes occurring in margarine stored at 4 and 20 degrees C were studied during the guarantee period declared by the producer (136 days). Fatty acid composition of triacylglycerols, homologous tocopherols, energetic value, peroxide value and water content were determined. It was stated that the composition of fatty acids and percentage of essential fatty acids (EFA) did not change significantly by time until the peroxide value reached the standard (4 mmol O2/kg). With peroxide values up to 5.5 considerable decomposition of tocopherols took place: alpha-tocopherol 50%, gamma-tocopherol 47% and delta-tocopherol 37%. The vitamin E content (34 i.u.), the EFA content (23%) and their physiological advantageous mutual relationship (Harris coefficient 1.44), which undergo slight changes during storage at 4 degrees C for the guarantee period, allowed to consider the studied margarine as a nutritionally valuable foodstuff. However, during storage at 20 degrees C, when the oxidation is accelerated, the margarine quickly loses its nutritive value. The energetic value of the margarine was lower than that of the products defined as margarine (more than 80% of fat, about 3200 kJ), and it amounted to 3029 kJ. It slightly decreased during storage of the margarine.     

Effects of pan-frying in margarine and olive oil on the fatty acid composition of cod and salmon

Effects on the fatty acid composition of cod (Gadus morhua) and salmon fillets (Salmo salar) after pan-frying in margarine and olive oil were determined. The fatty acids of the margarine used were 55.5% saturated (SFA), 33.0% mono-unsaturated (MUFA) and 11.5% polyunsaturated (PUFA). The olive oil used contained 15.4% SFA, 76.1% MUFA and 8.5% PUFA. Using margarine or olive oil increased the SFA and MUFA percentages, respectively, in both species. For cod fillets (lean), pan-frying increased the fat content (0.55–4.15 g/100 g and 0.55–2.30 g/100 g before and after pan-frying, with margarine and olive oil, respectively), whereas, for salmon fillets (fat), it decreased (13.91 to 10.57 g/100 g and 15.35 to 12.95 g/100 g before and after pan-frying with margarine and olive oil, respectively). In conclusion, the culinary fat selection affects the total fatty acid content and composition of the prepared fish fillet.     

Simultaneous rice bran oil stabilization and extraction using sub-critical water medium

Sub-critical water technique was used for simultaneous inactivation of lipase enzyme existing in rice bran and extraction of its oil in order to obtain the stabilized edible rice bran oil. Sub-critical water treatment was carried out in the temperature range between 120 and 240 °C for 10 and/or 20 min residence time in a batch reactor. The quality of the extracted oil was evaluated with respect to its total free fatty acids concentration over a 12 week period, and compared with the oil obtained by conventional extraction methods. Without sub-critical water treatment, the concentration of total free fatty acids in the rice bran significantly increased from 5.6% to 36.0%. In contrast, no increase was observed in the total free fatty acids concentration in the samples treated by sub-critical water. Experimental evidence showed that total free fatty acids concentration increased somewhat in the oils treated by conventional methods. Considering no change was observed in total free fatty acid concentration in the treated oils by sub-critical water, it was found that sub-critical water not only could efficiently extract oil from rice bran in a short residence time but also completely stabilized the extracted oil. Oil extraction yields generally increased with increases in sub-critical water treatment temperature and residence time. The highest extraction yield of oil was 249 (mg/g dry matter) obtained at 240 °C and 10 min residence time. Oil extraction by sub-critical water could be conducted in a very short residence time (10 and/or 20 min). Also, the kinetics of free fatty acids formation in untreated rice bran was investigated and developed which successfully describes the concentration of total free fatty acids in the course of rice bran storage.     

猪油和单甘酯含量对菜籽油凝胶油性质的影响研究

考察了将猪油与菜籽油按一定比例混合,并以单甘酯为凝胶剂形成的混合凝胶油的性质,探讨猪油和菜籽油质量比及单甘酯含量对混合凝胶油性质的影响,以制备出低饱和脂肪酸、能够更好地部分替代猪油的菜籽油混合凝胶油。测定了混合凝胶油的流变性质、质构性质、固体脂肪含量以及热力学性质。结果表明,当猪油和菜籽油质量比为5∶5,加入8%的单甘酯时,混合凝胶油与菜籽油凝胶油相比凝胶性质更好,在常温下固体脂肪含量更接近猪油。