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。     

油脂品种对肉桂酸基油脂凝胶形成及性质的影响

菜籽油、玉米油和亚麻籽油为基料油添加肉桂酸,经加热搅拌、冷却静置后形成油脂凝胶。研究油脂品种对油脂凝胶临界成胶质量分数、持油性（oil binding capacity,OBC）、硬度、固体脂肪含量（solid fat content,SFC）、凝胶晶型及微观结构的影响。结果表明,油脂品种对油脂凝胶临界成胶质量分数无影响,临界成胶质量分数均为4%;对OBC有一定的影响,且随肉桂酸质量分数的增加油脂凝胶OBC明显增强;菜籽油油脂凝胶硬度最小,亚麻籽油油脂凝胶硬度最大;对SFC的影响为菜籽油油脂凝胶＜玉米油油脂凝胶＜亚麻籽油油脂凝胶。同时,晶型分析表明3?种油脂凝胶主要晶型均为β和β′。通过偏光显微镜观察出3?种油脂凝胶的晶体结构及晶体分布差异明显,说明油脂品种对油脂凝胶的微观结构有显著影响。     

Thermal and rheological properties of organogels formed by sugarcane or candelilla wax in soybean oil

Sugarcane wax (SCW) was used to produce organogels and their properties were compared to candelilla wax (CLW) organogels a well known material for this purpose at concentrations of 1 to 4% (w/w). An empirical phase diagram showed that both waxes can form organogels with soybean oil as immobilized phase, SCW organogels were formed at higher concentration and at lower temperatures. The thermal behavior for SCW and CLW was similar, especially during crystallization (T_Onset and T_Peak of 42 °C and 41 °C respectively) differing only on enthalpy (1.957 and 4.829 J/g respectively), meaning that SCW organogels need less energy to form a network; the melting behavior showed that SCW organogels also need less energy to melt and that both materials presented two melting peaks one of the break of the network and melting of waxes. Rheological behavior presented similar behavior, but with higher values of complex modulus for CLW organogels. In the same way CLW gels showed larger mechanical resistance on compression/extrusion. Micrographs of organogels showed a more organized network present on CLW organogel than SCW organogels that showed larger crystals comparing to CLW organogels. The difference on the microstructure observed explains the difference on the mechanical behavior of organogels formed with both materials.     

天然蜡基油脂凝胶制备、结晶特性及应用研究进展

油脂凝胶化工艺是最具潜力的零反式脂肪酸、低饱和脂肪酸塑性脂肪制备技术之一。油脂凝胶是通过向液态植物油中添加凝胶剂,在加热搅拌或模板脱水等加工条件下获得的具有热可逆、类固态行为的脂质固形物。天然蜡因其价格低廉、容易获得,且能在较低浓度下构建具有较强质构特性的油脂凝胶,被证明是最有效的结晶型凝胶因子。本文系统综述不同组成的天然蜡构建蜡基油脂凝胶的工艺,重点讨论影响蜡基油脂凝胶结晶特性的因素,简要阐述蜡基油脂凝胶的主要优势及其应用情况。在此基础上,对天然蜡基油脂凝胶在食品专用油脂工业化生产中的开发、所遇到的挑战和未来的发展进行讨论。     

不同种类凝胶因子对芝麻油基凝胶油特性的影响

以芝麻油为原料,通过添加虫胶（Shellac,LAC）、单硬脂酸甘油酯（Monoacylglycerol,MAG）、乙基纤维素（Ethyl Cellulose,EC）三种不同种类凝胶因子制备出构型不同的凝胶油,并对凝胶油的持油能力、硬度、热力学性质、结晶形态等特性做了初步研究。结果表明,凝胶因子种类及添加比例对凝胶油临界成胶有一定影响,添加比例不小于5%时,LAC、MAG能形成凝胶,添加比例为3%时,EC能形成凝胶油;凝胶因子种类对持油性（Oil Binding Capacity,OBC）有重要影响,在凝胶因子添加比例为9%时,LAC凝胶油的OBC值最小,为55.3%;凝胶因子对硬度的影响中,三种不同凝胶油的硬度都随着凝胶因子添加比例增加而增大;在DSC曲线中,LAC凝胶油呈单峰、MAG凝胶油呈双峰、EC凝胶油峰度不明显;通过偏光显微镜观察,发现三种凝胶油的晶体形态结构及分散情况差别较大,LAC凝胶油晶体颗粒较小,呈细丫状;MAG凝胶油晶体颗粒偏大,先呈小球状后随添加量增大呈针状,表明凝胶油的微观结构受到凝胶因子种类的影响。     

Physicochemical properties and oxidative stability of oleogels made of carnauba wax with canola oil or beeswax with grapeseed oil

Two types of oleogels—made of carnauba wax with canola oil or beeswax with grapeseed oil—were prepared at concentrations from 0 to 15% (w/w) of wax. Physical characterization was done and oxidative stability of the oleogels were evaluated. As the proportion of wax increased from 5 to 15%, the enthalpy of crystallization and melting increased in both oleogels. The carnauba wax-based oleogel (CWO) required greater enthalpy than the beeswax-based oleogel (BWO). Differences in L*, a*, and b* values between control oils and the oleogels significantly decreased as the concentration of wax increased in the oleogels (5–15%; p<0.05). Oil-binding capacity of the BWO was higher than that of the CWO. Solid-fat content of the CWO did not change significantly from 10 to 60oC, whereas that of the BWO decreased. In general, oxidative stability of the CWO was better at 60 and 180oC heat treatment in comparison with control oils (p<0.05). However, the BWO did not provide high oxidative stability than the control oils.     

Structural and rheological properties of medium-chain triacylglyceride oleogels

This research studied the effect of gelator molecules on structural properties of oleogels containing medium-chain triacylglycerides (MCTs). To this aim, a large selection of gelators (rapeseed wax RAW, rice wax RW, sunflower wax SW, beeswax BW, monoglycerides MG, and γ-oryzanol and β-sitosterol mixture γ+β) at increasing concentrations (5–15% w/w) was considered. Results showed that RAW was not able to structure MCT at any concentration. However, addition of 5% (w/w) of MG, SW and BW resulted to a self-standing gel. Regarding γ+β and RW, gel structures were generated at 10% (w/w). By increasing the concentration, a reinforcement of the network strength was highlighted by the progressive increase of the rheological parameters. The strongest oleogel obtained by γ+β at 10% (w/w) and further BW and RW at 15% (w/w) concentration. These findings could provide interesting information in the choice of the best performing MCT structuring agent for intended food applications.     

Development of Formulations and Processes to Incorporate Wax Oleogels in Ice Cream

The objective of this study was to investigate the influence of emulsifiers, waxes, fat concentration, and processing conditions on the application of wax oleogel to replace solid fat content and create optimal fat structure in ice cream. Ice creams with 10% or 15% fat were formulated with rice bran wax (RBW), candelilla wax (CDW), or carnauba wax (CBW) oleogels, containing 10% wax and 90% high‐oleic sunflower oil. The ice creams were produced using batch or continuous freezing processes. Transmission electron microscopy (TEM) and cryo‐scanning electron microscopy were used to evaluate the microstructure of ice cream and the ultrastructure of oleogel droplets in ice cream mixes. Among the wax oleogels, RBW oleogel had the ability to form and sustain structure in 15% fat ice creams when glycerol monooleate (GMO) was used as the emulsifier. TEM images revealed that the high degree of fat structuring observed in GMO samples was associated with the RBW crystal morphology within the fat droplet, which was characterized by the growth of crystals at the outer edge of the droplet. Continuous freezing improved fat structuring compared to batch freezing. RBW oleogels established better structure compared to CDW or CBW oleogels. These results demonstrate that RBW oleogel has the potential to develop fat structure in ice cream in the presence of GMO and sufficiently high concentrations of oleogel.     

小烛树蜡油脂凝胶的性质及作用机理研究

本文主要以小烛树蜡为凝胶剂,制备低芥酸菜籽油油脂凝胶。研究小烛树蜡添加量对油凝胶的相变、持油性、固体脂肪含量（solid fat content, SFC）、凝胶晶型及硬度的影响。实验结果表明,小烛树蜡添加量≥4%时,掺入低芥酸菜籽油中可制得具有固体性质的油凝胶,添加量为8%时,小烛树蜡使得持油能力（oil binding capacity, OBC）最强;SFC均在2%～6%之间,随着温度的升高,SFC减小;晶型分析表明小烛树蜡低芥酸菜籽油油凝胶主要晶型均在4.70 ?和3.80 ?附近;油凝胶硬度随着小烛树蜡添加量增大而逐渐增大,添加量为10%时小烛树蜡油凝胶硬度适中。为日后小烛树蜡油脂凝胶替代传统起酥油,生产具有高含量不饱和脂肪酸的烘焙食品提供理论基础。     

Structure and thermal properties of β-sitosterol-beeswax-sunflower oleogels

Oleogels of β-sitosterol (Sit) and beeswax (BW) were combined at varying ratios (w/w) and added to sunflower oil (SFO) at concentrations of 10 g per 100 g and 20 g per 100 g oil to prepare oleogels (Sit/BW/SFO). Structural and thermal properties were characterised and results showed that the hardness and enthalpy of oleogels were affected by the amount of β-sitosterol and beeswax in the oleogelator combination (Sit/BW, w/w). Oleogels with beeswax as the only oleogelator (Sit0/BW10) had the highest hardness and maximum enthalpy change. Gel network form was influenced by the crystalline behaviour of the oleogelator, and Sit0/BW10-oleogel was densely packed, spherical and white while Sit10/BW0-oleogel displayed a needle shape. X-ray diffraction patterns showed that the oleogel width of the crystals and D-spacing increased with increasing amounts of β-sitosterol and the FTIR spectra revealed that oleogels formed via non-covalent bonding and may be stabilised with physical entanglements.     

利用蜂蜡-米糠蜡制备大豆油凝胶油

利用蜂蜡、米糠蜡及其混合物作为凝胶剂,开发大豆油基凝胶油,并将制备的凝胶油与起酥油的物理性质进行比较。通过对2 种添加量下（5%、8%）蜂蜡和米糠蜡（蜂蜡与米糠蜡质量比10∶0、9∶1、8∶2、7∶3、6∶4、5∶5、3∶7、1∶9、0∶10）制备凝胶油的性质测定,结果发现随着米糠蜡比例的增加,凝胶油的硬度（11.9～140.4 g）呈先增加后减小再略有增加的趋势,当蜂蜡与米糠蜡比例为8∶2时,凝胶油的硬度最大,表明蜂蜡和米糠蜡混合后有协同作用;同时析油率采用离心的方法评价,结果发现米糠蜡比例较低（蜂蜡∶米糠蜡＞5∶5）时,凝胶油稳定,析油率为0%,且添加量8%条件下凝胶油的析油率低于普通起酥油。同时固体脂肪曲线、差示扫描量热法结果显示,在10～40 ℃条件下凝胶油的固体脂肪质量分数（8.5%～4%）显著低于起酥油（65%～20%）;融化峰值温度（50.2 ℃）高于起酥油（43.1 ℃）;X射线衍射结果显示8%蜂蜡-米糠蜡（8∶2）凝胶油样品的晶体形态（β’）与起酥油接近,都是细小的结晶。应用发现,蜂蜡与米糠蜡比例为8∶2,添加比例为8%的凝胶油具有较好的烘焙效果,使最终产品的固体脂肪含量大大降低,或许能为消费者拥有更健康的产品提供一条可行途径。     

Characterization of Hazelnut Oil Oleogels Prepared with Sunflower and Carnauba Waxes

In this study, hazelnut oil oleogels prepared with sunflower wax and carnauba wax were analyzed and compared with a commercial shortening. Oil binding capacities of sunflower wax oleogels were higher than 99%, while carnauba wax had a maximum value of 97.6% for 10% addition level. At 3% addition level of carnauba wax, no gel developed. The crystal formation time of sunflower wax was shorter. Although the highest (8.5%) solid fat content was observed in the 10% carnauba wax containing oleogel (HC10) sample, it was 30.4% in the commercial shortening sample at 20°C. The peak melting temperature of commercial shortening was 52.3°C, and among all organogels, sunflower wax oleogel at 3% addition level had the closest value (58.4°C). The melting enthalpies of the oleogels ranged from 4.3 to 20.3 J/g, while it was 10.9 J/g for the commercial shortening sample. The firmness and stickiness values in the oleogel samples were lower than that of commercial shortening sample. On the other hand, there was no significant change of firmness and stickiness during storage, indicating good stability (p ≤ 0.001). Especially the sunflower wax oleogels were very homogenous and smooth in structure. The polarized light microscopy pictures revealed needle-like crystals for sunflower wax and aggregate-like crystals for carnauba wax oleogels. The x-ray diffraction measurements of the crystals showed the β´ types of the polymorphic structures. Furthermore, the oleogels were very stable against oxidation during the storage period. Hazelnut oil organogels prepared with sunflower wax can be good source material for shortening or margarine-like products.     

Comparative Analysis of Olive Oil Organogels Containing Beeswax and Sunflower Wax with Breakfast Margarine

The purpose of this research was to develop olive oil organogels with sunflower wax (SW) and beeswax (BW) at 3%, 7%, and 10% addition levels and to compare these organogels with breakfast margarine (BM). The organogels and BM sample were stored at 2 different temperatures (4 and 20 °C), and the peroxide values (PVs) and textural properties were monitored for 3 mo. The PVs of all organogels were within legal limits and the gels were structurally stable throughout the storage period. The textural properties of 3% SW and 7% BW organogels were closely similar to BM. The solid fat contents of the organogels were lower than that of the BM. Moreover, the thermal properties of 3% BW gel were more similar to that of the BM. The results of X‐ray diffraction peaks, approximately 3.70 and 4.10 Å, were similar to β′ polymorphic form. In conclusion, both of the organogel types may have value in replacing BMs.     

甘蔗蜡制备稻米油基油凝胶及其相关性质

在稻米油中添加一定量的甘蔗蜡制成具有塑性的油脂凝胶。研究甘蔗蜡添加量对油脂凝胶硬度、热力学性质、固体脂肪含量（solid fat content,SFC）、X射线衍射（X-ray diffraction,XRD）和微观结构的影响。结果表明：在20 ℃条件下,油脂凝胶中甘蔗蜡添加量不小于7%时,即可出现凝胶行为。油脂凝胶体系的硬度、SFC、融化焓和结晶焓均随甘蔗蜡添加量的增多而增加。XRD结果显示,甘蔗蜡油脂凝胶中同时含有α、β、β’三种晶型,其中以β晶型为主,随着甘蔗蜡添加量增多,α和β’晶型的量增多。晶体呈球状,分布均匀。随甘蔗蜡添加量的增加,结晶数量增加,尺寸减小,导致分布密度增加,即甘蔗蜡添加量越高,硬度越大,结构化植物油的能力越强,形成油脂凝胶结构稳定性越好,表明在稻米油中加入甘蔗蜡可以形成油脂凝胶,该油脂凝胶中无反式脂肪酸,富含天然营养成分,具有适宜的油脂凝胶硬度及良好的结构稳定性等优势。     

Physical Characterization of Wax/Oil Crystalline Networks

The objective of this research was to evaluate the physical properties of different types of wax/oil systems. Olive (OO), corn (CO), soybean (SBO), sunflower (SFO), safflower (SAFO), and canola (CAO) oils were mixed with sunflower oil wax (SFOW), paraffin wax (PW), and beeswax (BW) at different concentrations (1% to 10%). Results from this study show that the physical properties of wax/oil systems is affected not only by the concentration and type of wax used, but also by the type of oil used. In general, wax/oil systems formulated with SFOW generated crystalline networks with high enthalpies (1 to 22 J/g) and high G ′ values (2 to 6 × 10⁶ Pa) compared with the values obtained for BW and PW. SFOW crystalline networks were characterized by needle‐like crystals independently of the wax concentrations and type of oil used. BW crystalline networks, however, were characterized by different crystal morphologies (needle‐like or spherulites) depending on the wax concentration and type of oil used. PW samples were characterized by a crystalline network formed by needle‐ and platelet‐like crystals. Enthalpy values of BW and PW samples were similar (0.3 to 20 J/g), but BW samples resulted in significantly higher (P < 0.05) G ′ values in the 5% and 10% samples with values of 3.9 × 10⁶ and 6.1 × 10⁵ Pa for 10% BW and PW, respectively.     

巴西棕榈蜡和单甘酯复配比对高油酸葵花籽油凝胶油结构和特性的影响

以高油酸葵花籽油为基料油,通过向其添加不同质量比的凝胶剂巴西棕榈蜡（carnauba wax,CW）与单甘酯（monoglyceride,MG）制备凝胶油。固定凝胶剂浓度为5%,探讨不同CW与MG的复配比对制备的高油酸葵花籽油凝胶油微观形态、凝胶晶型、热力学性质、硬度、持油性以及固体脂肪含量（solid fat content,SFC）的影响。结果表明:MG没有影响CW的熔化行为,二者没有形成共结晶,出现了偏晶现象,当CW与MG复配比为9:1时,MG晶体的存在促进了CW的结晶,同时CW的存在会抑制MG晶体的多晶态转变,提高体系的储藏稳定性;少量MG的加入显著降低了CW凝胶油的硬度（P<0.05）,当二者复配比为5:5并随着MG含量的增多和CW含量的减少,体系硬度显著增大（P<0.05）,在1:9时达到最大硬度137.33 g;MG的加入显著提高了CW凝胶油的持油性（P<0.05）,二者复配比为5:5时体系持油性最佳达到100%;CW与MG复配比为3:7时凝胶油在30~37.5 ℃的SFC明显低于CW和MG凝胶油,此时MG的加入对体系口感的改善起到了正向作用。     

米糠蜡对稻米油基凝胶油形成的影响及动力学

以三级稻米油为基料油,研究了米糠蜡(rice bran wax,RBW)添加量对凝胶油形成特性的影响及凝胶油结晶形成的动力学参数。结果表明:在25℃时,RBW添加量为4%时便可形成凝胶油。随着RBW添加量的增加,凝胶油的硬度明显增加,贮藏30 d后凝胶油硬度变化不显著。凝胶油的固体脂肪含量也随RBW添加量的增加呈增多趋势,凝胶油主要为β′晶体。4%和7%RBW添加量凝胶油晶体为絮状,添加量为10%时凝胶油晶体转变为长枝晶状且密度增大。该凝胶油仅有一个结晶峰,采用Avrami方程模型拟合出的直线具有良好的线性关系(R~2=0.934 31),说明Avrami方程能较好地适用于稻米油基凝胶油结晶过程的研究,得到Avrami指数n为1.396 83,表明该凝胶油的晶体成核为均相瞬时成核并按照一维与二维混合结晶方式生长。     

肉桂酸基油凝胶及其乳液的制备及理化性质表征

选择玉米油为溶剂,肉桂酸为凝胶剂制备油凝胶,探究其流变学、质构、持油性、热力学特性及凝胶剂晶体形态;以油凝胶为分散相,制备油凝胶乳液（O/W型）,分析其粒径、流变学、稳定性等物理性质。结果表明：肉桂酸临界成胶质量分数为4%,4?℃条件下存放的油凝胶持油性较常温条件下更好;肉桂酸质量分数越大的油凝胶硬度越大,热稳定性越好;肉桂酸在油凝胶中呈现随机分布的长纤维状聚集体;油相质量分数为10%～20%时,油相含量越低,其乳液粒径越小、黏度越低、物理稳定性越好。油凝胶在常温下稳定性较差,而油凝胶乳液在常温下能保持良好的稳定性,有益于其在食品工业领域的研发与应用。     

Storage stability of cod liver oil organogels formed with beeswax and carnauba wax

In this study, organogels of cod liver oil (CLO) with beeswax (BW) and carnauba wax (CW) were prepared, and compared with a commercial margarine (CM). Oil binding capacities (OBC) of BW organogels were over 99%, while CW had a maximum OBC value of 91.28%. Crystal formation time of BW was shorter. Although the highest solid fat content (SFC) was in the 10% CW containing sample (8.69%), it was 28.99% in the CM sample at 20 °C. The peak melting temperature of CM was 43.70 °C, and BW organogel at 3% addition had the closest values (45.42 °C). Firmness and stickiness values of the organogels were lower than that of CM sample. No significant change in the texture parameters during storage was detected, indicating good stability. There was no hurdle against oxidation by organogelation during storage. This study has shown that CLO organogels can be suitable spreadable products.     

GRAIN SORGHUM WAX AS AN EDIBLE COATING FOR GELATIN-BASED CANDIES1

Gelatin-based candies were coated with medium chain triglyceride (MCT) oil or MCT oil combined with grain sorghum or carnauba wax (8.7% w/w of oil). Compared with uncoated samples, oil/sorghum wax and oil/carnauba wax coatings were equally effective in reducing protein solubility of candies in water (25C) and differences between initial and final diameters of candies subjected to melting. At 0, 5, and 10 days of storage (over calcium sulfate), the candies were evaluated by sensory panelists for surface reflection, pink color, clarity, chalkiness, firmness, adhesiveness, chewiness, cohesiveness, sweetness, sourness, fruit flavor, off-flavor, and aftertaste. Firmness, adhesiveness, chewiness, cohesiveness, and sourness scores increased (P<0.05) linearly with storage time. Samples treated with sorghum or carnauba wax were less shiny, more opaque, chalkier, and had more intense off-flavor and aftertaste than uncoated samples. Samples treated with the laboratory-extracted sorghum wax rated lower than carnauba wax-treated samples for surface reflection, clarity, chalkiness, off-flavor, and aftertaste.