有机相中脂肪酶催化棕榈油酯交换反应生产代可可酯的研究

本文研究在有机相中,固定化1,3-位置特异性脂肪酸Lipozyme~(IM)催化棕榈油中的区分物(POMF)与硬脂酸之间的酯交换反应,考察了反应温度、有机溶剂、酰基供体、酶浓度、水活性等因素对酯交换反应的速度和产物组成的影响。由棕榈油生产代可可脂的最佳反应条件是:Lipozyme~(IM):POMF:硬脂酸:正庚烷=1:3:6:9(wt/％),a_w=0.55,温度60～65℃。     

棕榈油熔点检测影响因素的分析

对棕榈油熔点测定过程中关键点进行了探讨，关于实验材料的选取、样品的制备、毛细管的制备、样品固定化等进行了详细的分析，对实际检测工作起到了很好的指导作用。     

Pyro-catalytic deoxgenated bio-oil from palm oil empty fruit bunch and fronds with boric oxide in a fixed-bed reactor

The catalytic effect of boric oxide on the pyrolysis of empty palm oil fruit bunch (EFB) and oil palm fronds (OPF) in a fixed-bed reactor at 400 °C was investigated. Boric oxide was found to selectively reduce 50-80% of the hydroxyl and methoxy groups in both water soluble (WS) and non water soluble (NWS) fractions of the oil. The increase in water and char yield suggested that pyro-catalysis of boric oxide enhanced the cleavage of C-O bonds in the biomass polymers and the capability to retain the inherent oxygen of the biomass in the solid product. This allows organic compounds with less oxygen substitution to become volatile and condenses as bio-oil. A mechanism for pyrolysis of boric oxide with biomass showing the hydroxyl removal pathway is proposed in this study.     

Crude palm oil from interspecific hybrid Elaeis oleifera × Elaeis guineensis: Fatty acid regiodistribution and molecular species of glycerides

The composition and structure of triacylglycerols (TAGs) and partial glycerides of crude palm oil obtained from interspecific hybrid Elaeis oleifera × Elaeis guineensis, grown in Colombia, were fully characterised and compared to data obtained by analysing crude African palm oil. Hybridisation appears to substantially modify the biosynthesis of fatty acids (FAs) rather than their assembly in TAGs. In fact, total FAs analysis showed significant differences between these two types of oil, with hybrid palm oil having a higher percentage of oleic acid (54.6 ± 1.0 vs 41.4 ± 0.3), together with a lower saturated fatty acid content (33.5 ± 0.5 vs 47.3 ± 0.1), while the percentage of essential fatty acid, linoleic acid, does not undergo significant changes. Furthermore, 34 TAG types were identified, with no qualitative differences between African and E. guineensis × E. oleifera hybrid palm oil samples. Short and medium chain FAs (8:0, 10:0, 12:0, 14:0) were utilised, together, to build a restricted number of TAG molecular species. Oil samples from the E. guineensis × E. oleifera hybrid showed higher contents of monosaturated TAGs (47.5–51.0% vs 36.7–37.1%) and triunsaturated TAGs (15.5–15.6% vs 5.2–5.4%). The sn-2 position of TAGs in hybrid palm oil was shown to be predominantly esterified with oleic acid (64.7–66.0 mol% vs 55.1–58.2 mol% in African palm oil) with only 10–15% of total palmitic acid and 6–20% of stearic acid acylated in the secondary position. The total amount of diacylglycerols (DAGs) was in agreement with the values of free acidity; DAG types found were in agreement with the representativeness of different TAG species.     

Development of a Coconut- and Palm-Based Fat Blend for a Cookie Filler

Thirteen fat blends intended for cookie filler (CF) production that consist of 20–70 % palm mid-fraction (PMF), 20–70 % virgin coconut oil (VCO), and 0–10 % palm stearin (POs) were developed based on the solid fat contents (SFC) of the fat portions extracted from five commercial CF samples: A, B, C, D, and E. A mixture design was applied for fat blend optimization, and the combination that best approached the target SFC values was composed of 70 % PMF, 20 % VCO, and 10 % POs. The optimized coconut- and palm-based fat blend (O-CP) exhibited a steeper SFC profile, with 8.2 % (±0.2) SFC at 25 °C (room temperature) and 0.2 % (±0.2) SFC at 37 °C (body temperature); lower slip melting point of 34.0 °C (±0.0); and a lower iodine value (IV) of 40.25 g/100 g (±1.04). In addition, O-CP contained higher proportions of medium-chain fatty acids (MCFA) and lauric acid (C12:0) of 3.2 % (±0.18) and 9.7 % (±0.43), respectively. In terms of its thermal profile, O-CP showed no significant difference in terms of its crystallization range, 49.7 °C (±2.66) with the exception of sample C, but it exhibited a smaller melting range, 65.8 °C (±1.47), compared to the fat portions of the commercial samples. The ranges represented the span between the onset and offset temperatures of both crystallization and melting profiles as determined by differential scanning calorimetry.     

Thermal Degradation Kinetics of Carotenoids in Palm Oil

In the present work, a detailed study is performed for carotene thermal degradation in palm oil at four temperatures ranging from 170 to 230 °C. The heating process was carried out with injection of nitrogen, and the samples were collected every 20 min during a total heating period of 140 min. HPLC analysis was conducted to monitor the carotenoids and tocols variations over the heating time at each temperature. The experimental data were then compared to literature data concerning carotenoids thermal degradation. The thermal degradation kinetics of carotenoids in palm oil followed an order superior to 1. The dependence of constant rates with temperature obeyed the Arrhenius relationship. The activation energy for the carotenoids thermal degradation in palm oil was found to be 109.4 kJ/mol.     

Application of Ultrasound for Oil Separation and Recovery of Palm Oil

This work investigated whether ultrasound treatment could improve the oil recovery from the extract obtained from pressed oil palm mesocarp. Oil recoverable after subjecting two process streams from palm oil milling operations to ultrasound were compared to that obtained from corresponding samples without ultrasound treatment. The process streams examined were (i) the ex-screw press feed into the vertical clarification tank and (ii) the underflow sludge from the clarification tank. Oil recoverable was taken as the sum of decantable oil obtained after a gravity settling process at 85 °C for 1 h (skimmed oil) and oil released from the remaining colloidal dispersion after centrifugation at 1,000 g (centrifuged oil). Oil recoverable was dependent on the ultrasound treatment applied, type of transducer used and the feed stream. Increased recoverable oil was obtained by applying low frequency ultrasound (20 kHz) to the ex-screw press feed using a long rod radial sonotrode system but recoverable oil was decreased when a short single step cascade focused sonotrode system was used. High frequency ultrasound (400 + 1,600 kHz) increased recoverable oil from both process streams. Applying sequential low and high frequency ultrasound increased recoverable oil from the ex-screw press feed but decreased that from the underflow sludge. The use of high frequency ultrasound for improving oil recovery is a significant advance for palm oil milling operations.     

Production and Characterization of DHA and GLA-Enriched Structured Lipid from Palm Olein for Infant Formula Use

Palm olein was modified via lipase-catalyzed acidolysis reaction to obtain fatty acid composition and positional distribution similar to human milk fat. In the reaction, a free fatty acid mix containing 23.23 % docosahexaenoic (DHA), 31.42 % gamma-linolenic (GLA), and 15.12 % palmitic acid was employed. The DHA and GLA were incorporated into the structured lipid (SL) product to improve its nutritional value. Response surface methodology (RSM) was used to investigate the effects of reaction time and substrate mole ratio (palm olein to a free fatty acid mix) on the amount of palmitic acid at the sn-2 position of SL triacyglycerols (TAG), and on the total DHA and GLA incorporation. Gram-scale production of SL was performed using the conditions predicted by RSM to maximize the content of palmitic acid at the sn-2 position. Verification of the predictions from RSM confirmed its practical utility. The resulting SL had 35.11 % palmitic acid at the sn-2 position, with 3.75 % DHA and 5.03 % GLA. Differential scanning calorimetry and HPLC analyses of the TAG revealed changes in their polymorphic profiles and TAG molecular species of SL compared to palm olein. The SL from this study can potentially be used in infant formula formulations.     

Biohydrogen production from biomass and industrial wastes by dark fermentation

Hydrogen is a clean energy carrier which has a great potential to be an alternative fuel. Abundant biomass from various industries could be a source for biohydrogen production where combination of waste treatment and energy production would be an advantage. This article summarizes the dark fermentative biohydrogen production from biomass. Types of potential biomass that could be the source for biohydrogen generation such as food and starch-based wastes, cellulosic materials, dairy wastes, palm oil mill effluent and glycerol are discussed in this article. Moreover, the microorganisms, factors affecting biohydrogen production such as undissociated acid, hydrogen partial pressure and metal ions are also discussed.     

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。