非氢化棕榈起酥油结晶速率的研究

研究不含有反式脂肪酸的非氢化棕榈起酥油的结晶性质,利用差示扫描量热仪监测非氢化棕榈起酥油与不同比例的糖粉(质量比,1∶0.5、1∶1.0、1∶1.5及1∶2.0)混合以及从不同的起始加热温度下(30、35、40、42、45、50、60、70℃及80℃)的结晶过程的热量变化(以5℃/min降温到-10℃)。同时,也比较了非氢化棕榈起酥油与氢化棕榈起酥油的结晶性质。研究发现,糖粉能够作为油脂结晶必须的晶核,从而起到加速非氢化棕榈起酥油的结晶速率的作用;当起始加热温度在熔点以上时,非氢化棕榈起酥油的结晶推动力大于熔点以下时,此时的结晶速率也快于部分氢化棕榈油。本文为非氢化棕榈起酥油在食品工业中的应用奠定了理论基础。     

棕榈仁油与五种油脂相容性的研究

利用等温相图,研究了棕榈仁油与5种常见人造奶油基料油———棕榈油、棕榈油硬脂、棕榈油软脂、氢化棕榈油和牛脂之间的二元相容性。结果表明,棕榈仁油与棕榈油系列油混合物在20~25℃内出现严重的共晶现象,与牛脂在10℃内出现偏晶现象,在20~25℃出现严重的共晶现象。     

棕榈油在金华酥饼皮中的应用研究北大核心CSCD

为提高金华酥饼的品质和健康安全性,并降低其生产成本,以改善酥饼皮的油脂组成为切入点,通过加入部分棕榈油来代替原本单一的菜籽油。将5℃棕榈液油、24℃棕榈液油和45℃棕榈硬脂与菜籽油分别按1∶3、1∶1和3∶1混合并制作酥饼皮,通过油脂相容性研究、产品感官与质构评价分析棕榈油的合理添加量。结果表明:5℃棕榈液油与菜籽油完全相容,而24℃棕榈液油和45℃棕榈硬脂与菜籽油在室温下存在共晶现象;混合油脂中5℃棕榈液油的添加量达到75%、24℃棕榈液油的添加量达到50%或45℃棕榈硬脂的添加量达到25%时,可保证制作的金华酥饼在感官、质构方面与传统金华酥饼相近。     

棕榈油在金华酥饼皮中的应用研究

为提高金华酥饼的品质和健康安全性,并降低其生产成本,以改善酥饼皮的油脂组成为切入点,通过加入部分棕榈油来代替原本单一的菜籽油。将5℃棕榈液油、24℃棕榈液油和45℃棕榈硬脂与菜籽油分别按1∶3、1∶1和3∶1混合并制作酥饼皮,通过油脂相容性研究、产品感官与质构评价分析棕榈油的合理添加量。结果表明:5℃棕榈液油与菜籽油完全相容,而24℃棕榈液油和45℃棕榈硬脂与菜籽油在室温下存在共晶现象;混合油脂中5℃棕榈液油的添加量达到75%、24℃棕榈液油的添加量达到50%或45℃棕榈硬脂的添加量达到25%时,可保证制作的金华酥饼在感官、质构方面与传统金华酥饼相近。     

茶多酚棕榈酸酯对棕榈油抗冻性和煎炸稳定性的影响

为了对棕榈煎炸油的开发提供参考，以不同茶多酚棕榈酸酯(抗氧化剂)添加量的分提18℃棕榈油为煎炸油，通过10℃和15℃冷冻试验中煎炸油(茶多酚棕榈酸酯含量分别为0、50、80、100、150、200、300 mg/kg)晶体微量析出时间和发朦时间的变化，以及180℃下薯条煎炸过程中煎炸油酸值、p-茴香胺值、总氧化值、色泽、脂肪酸组成、极性组分含量和3-氯丙醇酯含量的变化，分析了茶多酚棕榈酸酯对棕榈油抗冻性和煎炸稳定性的影响。结果表明：棕榈油的发朦时间与抗氧化剂的添加量整体呈阶梯增长的关系，尤其在15℃条件下，其抗冻性在茶多酚棕榈酸酯含量为50 mg/kg和150 mg/kg时明显增强；煎炸油的酸值、p-茴香胺值、总氧化值、脂肪酸组成、极性组分含量与茶多酚棕榈酸酯添加量无相关性；添加茶多酚棕榈酸酯的棕榈油在煎炸后的色泽均比空白组深；3-氯丙醇酯在煎炸初期降解剧烈，后期降解缓慢，最终趋于平缓，与抗氧化剂的添加量无相关性。总之，向棕榈油中添加茶多酚棕榈酸酯可以明显提高其抗冻性，茶多酚棕榈酸酯含量为50 mg/kg或150 mg/kg时，其抗冻性改进效果最为明显，但是并不能有效提升煎炸油的煎炸稳...     

12度棕榈油超声强化结晶分提工艺研究

目的 改良棕榈油干法分提工艺,开展12度棕榈油超声强化结晶分提工艺研究。方法 以24度棕榈油为原料,采用三因素三水平正交试验,考察不同油样温度、超声功率、超声时间下,超声处理对棕榈油脂晶成长初期的平均粒径、液油产率和主要理化指标(熔点、碘价、酸值、过氧化值)的影响。结果 在棕榈油分提过程的关键结晶点施加超声波对棕榈油结晶行为有显著影响,超声波功率越强,脂晶成长初期的平均粒径越小,液油产率越高。在油样温度17.5℃时,以135 W超声30 s可达到最高液油产率37.63%。分提的各液油产品的熔点、碘价、酸值、过氧化值等理化指标均符合生产企业标准或国家标准要求;各液油产品的熔点与碘价之间没有明显的相关性,熔点和碘价与液油得率之间也没有明显的相关性;超声处理没有引起液油产品游离脂肪酸含量的变化,对液油产品的过氧化值也无不良影响。结论 在优化的超声处理条件下,超声强化结晶工艺能实现良好的固液分离,液油产率比对照组提高45.06%,且主要理化指标均符合企业品控标准。     

棕榈油干法分提条件研究

以碘价为54棕榈油为原料,采用干法分提制备棕榈油中间熔点物(POMF)。在单因素试验基础上,采用响应面优化实验,研究结晶温度、冷却速率和养晶时间对干法分提效果影响。得出棕榈油干法分提最佳工艺条件为:结晶温度16.83℃,冷却速率1.31℃/h,养晶时间13.39 h。在此条件下棕榈油中间熔点物(POMF)得率为30.3%,熔点为35.0℃,熔程为32℃³6℃。实验测定结果为:棕榈油中间熔点物(POMF)得率为29.9%,熔点为35.3℃,熔程为32℃36℃。实验测定结果为:棕榈油中间熔点物(POMF)得率为29.9%,熔点为35.3℃,熔程为32℃³6℃。     

不同熔点棕榈油脂肪酸组成和SFC测定分析

分析七种不同棕榈油脂肪酸组成及在0℃~25℃(5℃间隔)温度下固体脂肪含量(SFC)及其变化规律。结果表明:随熔点降低,棕榈酸含量有逐渐降低趋势,而油酸和亚油酸含量则逐渐上升;饱和脂肪酸含量逐渐减少,而不饱和脂肪酸含量则逐渐升高;低熔点棕榈油营养价值要比高熔点棕榈油高;在不同温度段,SFC值增加幅度有所不同。该试验为棕榈油进一步深加工研究提供参考数据。     

冷冻结晶法脱除生物柴油中的饱和脂肪酸酯制备脂肪酸酯类抗磨剂

为脱除饱和脂肪酸甲酯,得到合格的脂肪酸酯类柴油抗磨剂(饱和脂肪酸酯含量不高于2.5%),以生物柴油为原料,采用冷冻结晶法,考察了冷冻温度、搅拌速度、冷冻方式和原料组成对饱和脂肪酸甲酯脱除效果的影响。结果表明:过高的搅拌速度产生细小晶体,不利于晶体和熔融液的分离;冷冻温度与原料中棕榈酸甲酯的含量有关,当原料中棕榈酸甲酯的含量低于1.2%时,在-5℃下静置冷冻结晶,可以得到符合抗磨剂要求的产品,如果原料中棕榈酸甲酯的含量超过1.2%,必须在-20℃下进行静置冷冻结晶处理;逐级降温静置冷冻结晶方法有利于提高生物柴油中饱和脂肪酸甲酯的脱除效果和脂肪酸甲酯的收率,在-15℃下处理即可获得符合抗磨剂要求的产品。     

大豆油调和不同熔点棕榈液油的冷藏试验

为了制备适应不同储存温度的豆油-棕榈液油调和油,以大豆油与不同熔点棕榈液油为原料,采用冷藏试验方法优化抑晶剂种类、用量和调和油配方。结果表明,羟基硬脂精是效果最佳的抑晶剂,其最佳添加量为0.025%;调和油1(豆油70%+10℃棕榈油30% +羟基硬脂精0.025%)在0℃环境下储存可保持16h以上澄清透亮,在5℃条件可保持72h以上澄清透亮;调和油2(豆油70%+18℃棕榈油30%+羟基硬脂精0.025%)在10℃环境下可保持30h以上澄清透亮;调和油3(豆油60%+18℃棕榈油40%+羟基硬脂精0.025%)在15℃环境下可保持20h以上澄清透亮;调和油4(豆油60%+24℃棕榈油40%+羟基硬脂精0.025%)在20℃环境下可保持10h以上澄清透亮。     

Discrimination of palm olein oil and palm stearin oil mixtures using a mass spectrometry based electronic nose

To discriminate mixing ratios for mixtures of palm olein oil and palm stearin oil, an electronic nose based on mass spectrometer (MS-electronic nose) and GC were used. The intensities of each fragment from the palm olein oil and palm stearin oil by the MS-electronic nose were used for discriminant function analysis (DFA). When palm olein oil is mixed with palm stearin oil, more than 3% of stearin oil can be estimated by DFA. The obtained data were used for DFA. DFA plot indicated a significant separation of pure palm olein oil and palm stearin oil. The added concentration of palm stearin oil to palm olein oil was highly correlated with the first discriminant function score (DF1). When palm stearin oil was added to palm olein oil, it was possible to predict the following equation; DF1= −0.112×(conc. of palm stearin oil)+0.416 (r²=0.95). When palm stearin oil was added to palm olein oil, peak area of GC was correlated to DF1 by MS-electronic nose with ratio of palm olein oil vs palm stearin oil. The MS-electronic nose system could be used as an efficient method for the authentication of oil.     

Effects of chemical interesterification on physicochemical properties of blends of palm stearin and palm olein

Chemical interesterification is an important technological option for the production of fats targeting commercial applications. Fat blends, formulated by binary blends of palm stearin and palm olein in different ratios, were subjected to chemical interesterification. The following determinations, before and after the interesterification reactions, were done: fatty acid composition, softening point, melting point, solid fat content and consistency. For the analytical responses a multiple regression statistical model was applied. This study has shown that blending and chemical interesterifications are an effective way to modify the physical and chemical properties of palm stearin, palm olein and their blends. The mixture and chemical interesterification allowed obtaining fats with various degrees of plasticity, increasing the possibilities for the commercial use of palm stearin and palm olein.     

Crystallization properties of palm oil by dry fractionation

The crystallization, thermal, physical, chemical and morphological properties of palm oil were investigated using differential scanning calorimetry, polarized microscopy, pulsed nuclear magnetic resonance (NMR) and gas chromatography (GC). The palm oil was fractionated into various stearin and olein (with iodine values (IV)>63) fractions by means of a dry fractionation process. During the cooling sequence, samples were taken at regular intervals from the crystallizer and analyzed for their iodine values, chemical compositions and physical behaviour. The physical properties of olein and stearin fractions, such as cloud point, slip melting point and solid fat content, were dependent on the crystallization temperatures. The iodine values of the olein and stearin fractions increased as the crystallization temperature decreased and both fractions started to cloud at lower temperatures. The palmitic acid content of stearin and olein fractions was also affected by the crystallization temperatures.     

Crystallisation kinetics of palm stearin,palm kernel olein and their blends

The kinetics of isothermal crystallisation of palm stearin, palm kernel olein and their blends (20–80 g/100 g palm stearin with 20 g/100 g increment) were determined using differential scanning calorimetry (DSC). The mechanism of crystallisation (n) was calculated by applying the Avrami equation using the crystallisation curves obtained at 10, 15 and 20 °C. The DSC isothermal crystallisation data at 10, 15 and 20 °C fitted well into the Avrami equation over the entire fractional crystallisation with correlation coefficient always greater than 0.98. Based on the Avrami exponent obtained, the palm stearin and palm kernel olein have different nucleation and growth mechanisms. The suggested mechanism for palm kernel olein was high nucleation rate at the beginning of crystallisation, which decreased with time, and plate-like growth (n = 2). On the other hand, the mechanism for palm stearin was instantaneous heterogeneous nucleation followed by spherulitic growth (n = 3). For blends of palm stearin and palm kernel olein, the mechanisms of crystallisation were 2 and 3 depending on the composition of the blends and crystallisation temperatures.     

利用棕榈油制备速冻食品专用油脂

以棕榈硬脂和棕榈液油为原料,开发适用于速冻食品的专用油脂生产技术及配方。将棕榈硬脂与棕榈液油按质量比1∶1复配,用于制备速冻食品专用油脂。通过正交实验分析,确定了专用油脂制备的最佳条件为:复合乳化剂(丙二醇酯与单甘酯质量比为1∶1)添加量为油质量的1%,乳化温度60℃,乳化时间10 min,油水质量比5∶1。在最佳条件下,制得的专用油脂的乳化稳定性为92.2%。     

Physicochemical Properties and Sensory Attributes of Medium- and Long-Chain Triacylglycerols (MLCT)-Enriched Bakery Shortening

Six binary formulations of medium- and long-chain triacylglycerols (MLCT) fat and palm stearin and four ternary formulations of MLCT fat, palm stearin, and palm olein were produced. MLCT fat and palm stearin were mixed in ranges of 40–90% with 10% increments (w/w), while for the ternary formulations, 10% and 20% palm olein were substituted to palm stearin in MS 46 and MS 55 formulations. The solid fat content (SFC) by pulsed nuclear magnetic resonance and heating profiles using differential scanning calorimeter of these formulations were determined. Results obtained from SFC and heating profiles found that all the formulations melted completely at 55 °C. The high complete melting temperature is due to the stearic acid content in MLCT fat. Generally, increasing % MLCT fat (40–90%) in the formulations lowers the SFC curves at the measured temperatures (0–60 °C). The binary samples of MS 73, MS 82, and MS 91 showed SFC between 15% and 25% at room temperature (25 °C), which indicated that these formulations were suitable for shortening production. As the production cost of MLCT fat is high (approximately USD 3/kg), an attempt to reduce the proportion of MLCT fat in the shortening formulations was done by developing the ternary formulations. Shortenings formulated with 40:40:20 (MSO 442), 50:40:10 (MSO 541), and 50:30:20 (MSO 532) of MLCT fat/palm stearin/palm olein formulations had similar SFC% at 25 °C, and they were subsequently chosen to produce shortening. Using multivariate analysis, taste attribute showed positively and highly correlated to the melting temperature and SFC at 25 °C of the MLCT-enriched shortenings. In acceptance test, high correlation (R ² = 0.98) was only found on cakes made from MSO 442 and MSO 541 shortenings. Both untrained and trained panelists rated the Madeira cakes made from MSO 532 shortening the highest for overall acceptability.     

单硬脂酸甘油酯对棕榈硬脂固体脂肪含量及硬度的影响

食品工业中通常利用乳化剂调控塑型脂肪的物理性质及加工性能,其中,单硬脂酸甘油酯(GMS)是应用较为广泛的乳化剂。通过考察质量分数1%,2%,4%的GMS对棕榈硬脂在不同温度下的固体脂肪含量(SFC)、硬度及微观结构的影响,发现:棕榈硬脂及其与质量分数1%,2%,4%的GMS混合物的SFC和硬度随着温度的升高而降低。GMS的添加量对棕榈硬脂SFC的影响在较高温度(21.1~33.3℃)下更显著,当GMS添加量高于1%时,棕榈硬脂的SFC随GMS质量分数的增加而增加。而在15~30℃时,4%GMS的棕榈硬脂的硬度显著高于其它质量分数,且结晶颗粒细小,结晶网络结构致密。结果表明,在温度高于30℃时,添加GMS可以增加棕榈硬脂的SFC及硬度,且减小其结晶颗粒粒度,赋予更为致密的结构,这对棕榈硬脂基塑性脂肪在温度较高季节的储运及品质改善提供了理论依据。     

隔膜压滤机在棕榈油干法分提中的应用

隔膜压滤机用于棕榈油分提过程的固液分离,在过滤完成后,通过压缩介质(水或空气等)依靠隔膜对滤饼压榨、挤干.采用隔膜压滤机,棕榈硬脂硬度提高、棕榈液油得率增加,分离效果好.过滤过程应用自动化控制,操作方便、产品质量稳定.     

VISCOELASTIC PROPERTIES OF TABLE MARGARINE PREPARED FROM LIPASE-CATALYZED TRANSESTERIFIED MIXTURES OF PALM STEARIN AND PALM KERNEL OLEIN

A controlled-stress rheometer was used to evaluate dynamic viscoelastic (VE) performance of an experimental table margarine prepared from a transesterified palm stearin (PS):palm kernel olein (PKO) mixture (40:60 ratio) using Rhizomucor miehei lipase as the biocatalyst. Comparison was made using a commercial table margarine made of palm oil and palm kernel oil. The experiments were carried out over a period of three months with the margarines kept at 20 and