方便面生产中棕榈油稳定性的分析

对方便面生产中使用的两种不同凝固点(24℃与33℃)棕榈油的酸值、过氧化值、水分进行了分析,并探讨了棕榈油劣变的防止措施。分析结果表明,33℃棕榈油较24℃棕榈油稳定性高,成品方便面含油率低,更适于方便面的生产。在实际生产中,可通过严格控制煎炸温度,减少进入油炸锅中的水分,添加抗氧化剂等措施,防止棕榈油劣变。     

不同储备条件对储备棕榈油氧化稳定性的影响

针对高温高湿的珠三角地区储备的24度精炼棕榈油,以及常规储备精炼棕榈油出现的问题,重点探究了不同储备条件下金属离子和温度两个因素对棕榈油氧化稳定性的影响。试验结果表明,储备油罐若未作食品级内防腐处理,储备期间油罐内壁氧化产生的金属离子会对棕榈油产生明显的促氧化作用,棕榈油氧化速度明显加快,过氧化值快速升高,酸值有变化但不明显;等同质量的棕榈油,在夏季高温期入库储藏要比冬季低温期入库储藏更容易氧化变质。     

超声处理对红花籽油理化性质及脂肪酸组成的影响

研究了不同超声条件下,红花籽油过氧化值、酸值、皂化值及脂肪酸组成的变化规律。结果表明:超声温度控制在50℃以下,超声功率小于等于600 W,超声时间短于60 min时,超声处理对红花籽油的过氧化值、酸值无明显影响,当超声功率高于600 W时,过氧化值、酸值随超声时间的延长而增加;超声温度控制在50℃以下,超声功率小于等于900 W,超声时间短于60 min时,超声处理对红花籽油脂肪酸组成没有影响,对脂肪酸含量和皂化值有较小的影响。     

超声波作用下棕榈油酯交换反应的研究

将超声波技术应用于棕榈油的酯交换反应。通过单因素试验研究了超声波功率、反应时间、醇油摩尔比、反应温度对棕榈油酯交换率的影响。在单因素试验的基础上进行正交试验优化得到的超声波酯交换反应参数为:超声波功率280 W,反应时间30 min,醇油摩尔比7.5∶1,反应温度55℃,此条件下的酯交换率可达95.5%。对比常规搅拌酯交换法,超声波法明显促进了酯交换反应,降低了反应温度,缩短了反应时间。     

茶多酚对棕榈油抗氧化性的研究

在棕榈油中添加茶多酚,维生素E及茶多酚与柠檬酸的混合物,对油脂的 PV 和 AV 进行测定,结果表明,它们均有抑制棕榈油 PV 和 AV 升高的作用.在相同剂量下,茶多酚的抗氧化能力最优。     

超声波和相转移催化剂在棕榈油皂化反应中的应用研究

以棕榈油为原料,对其非均相皂化反应进行了研究.对催化剂及皂化处理方式进行考察,并在此基础上选择反应温度、超声波功率、反应时间、催化剂添加量、KOH添加量进行了单因素优化实验.结果表明:相转移催化剂CTAB催化效果最好,超声波辅助搅拌处理方式最佳;单因素优化的最优皂化条件为反应温度70℃,超声波功率320 W,反应时间80 min,催化剂CTAB添加量0.5g(以每克油计),KOH添加量1.75 g(以每克油计).在最优条件下皂化率达到89.32％,是常规搅拌(无催化剂,无超声波作用)下皂化率的4.7倍,大大提高了效率.     

超声波处理对淀粉结构与性质影响

淀粉是很多食品必要组分和重要加工原料,为改善淀粉性能、扩大其应用范围,常需对天然淀粉进行改性;化学法和酶法是淀粉改性主要方法,但存在反应速率低、环境污染或反应过程相当复杂等问题。该文介绍一种新的淀粉改性技术―超声波技术,较全面综述超声波处理对淀粉分子量、表面结构、结晶结构与凝胶质构特性、流变特性、热性质、反应性能等影响,并对超声波技术在淀粉改性方面应用前景进行展望。     

超声波处理对玉米淀粉流变性质的影响

本文研究了不同功率超声波处理玉米淀粉的流变性质.结果表明,所有淀粉糊均呈现假塑性流体特征.随着超声功率的增大,其处理的淀粉糊触变性减弱.     

对食用植物油品质的影响因素分析

分析了水分、时间、温度及油脂中杂质等因素对油脂品质的影响,并提出了有效保护油脂品质的储存措施。     

两种棕榈油煎炸前后稳定性研究

从方便面生产中使用的两种不同熔点(24℃与33℃)棕榈油的使用现状出发,对棕榈油的酸价、过氧化值、水分及挥发物值进行分析比较,筛选出更加适合于方便面生产的煎炸油。实验结果表明,33度棕榈油较24度棕榈油的稳定性高,适合于方便面的生产。      

棕榈油大豆油为原料调和油冷冻性能研究

对碘值60棕榈油与大豆油调和而成调和油在0℃、10℃、20℃三种温度条件下进行冷冻性能研究。在0℃情况下,即使棕榈油含量仅10%,也会很快混浊和结冻;在10℃情况下,含20%棕榈油的棕榈油大豆油调和油可保持15天以上澄清透明;在20℃情况下,含40%棕榈油的棕榈油大豆油调和油可保持25天以上而澄清透明。     

The physical properties of modified palm oil

Palm oil has been treated by partial lipase hydrolysis and by interesterification with excess glycerol and the effects on the chemical and physical properties have been investigated. Lipase hydrolysis preferentially removes unsaturated acids and the neutral glycerides remaining after removal of the free fatty acids therefore have an increased solids content at 20°C. Both differential scanning calorimetry (d.s.c.) and X-ray examination show that the crystalline phases present above 20°C are more heterogeneous after lipase treatment. Interesterification results in a mixture of tri- and diglycerides with an increased solids content at 20°C and a marked tendency to form β phase crystals. Some potential practical applications are discussed.     

Evaluation on some finishing properties of oil palm plywood

Oil palm is the largest and most important plantation crop in Malaysia. The oil palm generally lasts for 25–30 years before the next replantation is done. Substantial amount of biomass in the form of palm trunk results from plantation cycle. This resource is simply left on the ground to decay and is not used as raw material to manufacture any kind of value-added products. The objective of this study was to investigate the possibility of manufacturing plywood from oil palm trunks and to evaluate some of the finishing properties of such experimental panels in comparison to those from Shorea sp as control samples. Three-ply plywood samples were produced from 5 mm thick veneers of oil palm using urea formaldehyde adhesive. Three types of chemicals, namely nitrocellulose, pre-catalyzed lacquer and polyurethane were used to finish experimental panels. The surface finished with nitrocellulose had the lowest contact angle on raw surface of oil palm plywood and wood. The average cross cut tape index of oil palm plywood was comparable to Shorea sp. All finishing materials of oil palm plywood produced impact rating of 4 except for surface finished with nitrocellulose while finishing on wood indicated an impact rating of 3. Oil palm plywood had higher weight loss compared to Shorea sp. Based on results from contact angle, cross cut tape index, impact rate test, weathering, and soil burial test methods it appears that the samples showed acceptable finishing properties comparable to those of solid wood.     

Effects of ultrasonic treatment on wool fibre and fabric properties

The protein structures of wool, treated in fabric form with ultrasonics for different time durations, were analysed by X-ray diffraction (XRD) and Fourier transform infrared (FTIR), in comparison with the wool without ultrasonic treatment. Fabric water absorption and tensile properties were measured in addition to the fibre micro-structure analysis. It is shown that while the ultrasonic treatment had little effect on the fibre crystallinity, some chemical structures in the protein were altered to some extent during the process. Disruption of fibre internal waxy lipids upon ultrasonic treatment provided the fibres with increased water absorption. Protein chains in the macro fibrils were shown to be rearranged to a more regular and less flexible structure, as a result of the ultrasonic treatment. Fabric tensile tests showed an increased tenacity and a reduced extensibility to the ultrasonically treated fabric. Prolonged ultrasonic treatment, however, significantly reduced both fabric tenacity and extensibility.     

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.     

超声波处理对青稞淀粉理化特性的影响

为研究超声波作用对青稞淀粉理化特性的影响,本试验利用超声波（100W~500W）对青稞淀粉进行处理,结果表明：首先,超声波对青稞淀粉颗粒结构有损伤作用,随着超声功率的增大,淀粉颗粒表层结晶结构被破坏程度逐渐加深,最终淀粉颗粒被冲击成片状。同时淀粉的溶解度、膨胀力、淀粉糊透明度随超声功率的增强先增大后降低,在功率100W处有较大透明度,当超声功率≧400W时,青稞淀粉膨润力明显下降。其次青稞淀粉糊化特性受超声波影响,与原淀粉相比,随着超声功率的增加,青稞淀粉峰值黏度、谷黏度、崩溃值、最终粘度、回生值显著性降低（P<0.01）;最后发现超声波处理后青稞淀粉未能产生新的基团,但某些吸收峰强度因处理强度不同有显著差异。随着超声功率的增强,青稞淀粉糊化起始温度（To）、峰值温度（Tp）、终了温度（Tc）与原淀粉相比都有所升高,其中青稞淀粉的糊化起始温度极显著增高（P<0.01）,而淀粉峰值温度与Tc-To呈阶梯型变化。     

薯类淀粉糊在超声场中凝胶质构特性研究

以木薯淀粉、红薯淀粉以及马铃薯淀粉为研究对象,研究了不同浓度、不同超声场作用时间、功率和温度对淀粉糊凝胶质构特性的影响。结果表明,在相同浓度下,马铃薯淀粉糊凝胶强度、压缩功和黏附性显著高于木薯淀粉和红薯淀粉。3种薯类淀粉糊经超声场作用后,淀粉糊质构特性发生显著变化,凝胶强度均呈降低趋势。超声波处理能有效改变薯类淀粉糊质构特性,超声作用对不同薯类淀粉糊的影响存在显著差异。     

棕榈油和棕榈仁油的地位和现状

中国是一个油脂资源非常贫乏的国家 ,每年都要从国外进口大量的油脂以满足人民生活及工业需要。据统计 ,1997年中国进口的大豆油是 2 0 0万吨 ,棕榈油 16 2万吨 ,棕榈仁油 1 5万吨 ,其中棕榈油的消费量已位居第 4(见表 2 )。预计 ,至 2 0 0 5年 ,世界棕榈油的消费量将超过大豆油 (见表 1)。作为具有巨大市场潜力和价值的油脂资源 ,国外就棕榈油和棕榈仁油的生产、物理和化学性质及其应用等方面的研究已日趋深入[1] ,但在我国有关棕榈油和棕榈仁油的研究和介绍资料极少。为此 ,希望通过本文的介绍 ,能加深对棕榈油和棕榈仁油的了解 ,并能引起…