Effect of γ-irradiation on enzymatic digestion of oil palm empty fruit bunch

Effect of γ-irradiation and combination treatment with alkali on oil palm empty fruit bunch (EFB) was studied to enhance the efficiency of enzymatic digestibility. γ-Irradiation enhanced the enzymatic digestibility, and the amounts of released galacturonic acid and neutral sugars from EFB by Driselase were increased with an increase in irradiation dose. The main components of neutral sugars released from EFB were glucose and xylose. EFB treated with alkali and 50 kGy irradiation released 1200 μg g^?1 of xylose that was twice amount of glucose showing that the combination treatment was effective especially to increase the digestibility of xylan.     

Effect of gamma irradiation on microorganisms and components in empty fruit bunch and palm press fibre of oil palm wastes

The effects of irradiation on microbiological load and chemical components of empty fruit bunch (EFB) and palm press fibre (PPF) were investigated as the preliminary study for upgrading of oil palm wastes to animal feeds by fermentation. The initial contamination of microorganisms in both EFB and PPF was very high and there is no significant difference between the samples collected from various palm oil mills. The dose required to eliminate below the detectable level was more than 15 kGy for total aerobic bacteria, but 5–6 kGy is enough for fungi. The contents of holocellulose and lignin were c 60% and 25%, respectively, in both EFB and PPF, and the change in components by irradiation was small. EFB and PPF have a high water holding capacity suggesting that they are suitable substrates for fermentation. These results show that the irradiation by 5–10 kGy on EFB and PPF is applicable for the pasteurisation of fermentation media without any significant change in components.     

Preservation of oil palm fruit and oil palm fruit mesocarp by gamma irradiation

Experiments were conducted to determine the potential of gamma radiations in the extension of the shelf-life of oil palm fruit and oil palm fruit mesocarp. In the course of the experiment, it was observed that even though palm fruits in their harvested form, went bad within 3 days post-harvest, their shelf-life can be extended to at least 2 months through preparation of dry oil palm fruit mesocarp. Furthermore, despite the fact that gamma radiation cannot be used to prolong the shelf-life of oil palm fruit proper, it can be used to drastically reduce the mould load in the dry palm fruit mesocarps, thereby further enhancing their keeping quality and consumer acceptance. Chemical and organoleptic analyses of fat extracted from irradiated, dry oil palm fruit mesocarp show that there is practically no radiation effect. The significance of these observations is discussed in relation to the possible acceptance of radiation-preservation of oil palm fruit mesocarp commercially.     

棕榈油基绿豆糕的制备工艺研究

传统绿豆糕的制作多采用大豆油或以大豆油为基础油的调和油,为提高产品的货架期、经济价值和营养价值,选用5℃棕榈油、24℃棕榈油和45℃棕榈油分别部分替代大豆油制作绿豆糕,以棕榈油添加量、复配油脂添加量和复配油脂加热时间为试验因素,以产品的感官评分和硬度为参考指标进行优化试验。结果表明:5℃棕榈油基绿豆糕,棕榈油添加量为80%、复配油脂添加量为20%、复配油脂加热时间为3.5 min;24℃棕榈油基绿豆糕,棕榈油添加量为80%、复配油脂添加量为23%、复配油脂加热时间为3.0 min;45℃棕榈油基绿豆糕,棕榈油添加量为60%、复配油脂添加量为12%、复配油脂加热时间为4.5 min。按上述工艺制作的绿豆糕,其感官评分和硬度与传统绿豆糕相近。     

Production of high-oleic palm oil nanoemulsions by high-shear homogenization (microfluidization)

Nanoemulsions present benefits such as an increase in the bioavailability, solubility and targeted delivery of encapsulated substances, and thus, they are a method of incorporating high nutritional value oils, such as high-oleic palm oil (HOPO). In this work, O/W nanoemulsions were obtained by microfluidization using HOPO (1–20% w/w) in the oily phase along with whey (1–20% w/w), Tween 20 (1:1 w/w ratio) and water in the aqueous phase following a surface response design methodology. The response variables were the average drop size (ADS), the polydispersity index (PDI), the zeta potential (ζ), CIELAB color parameters and viscosities of the fresh nanoemulsions (0 days) and nanoemulsions stored at two temperatures (5 and 19 °C) for 4 days. The ADS, PDI and ζ values varied between 163 and 2268 nm, 0.2 and 1, and − 29.7 and − 47.2 mV, respectively. The viscosity was affected by the storage temperature; after 4 days at 19 °C, it increased almost 6-fold compared to the viscosity of the fresh sample. With regards to the color parameters, significant changes were observed based on the concentrations of HOPO and whey. In addition, the prediction equations only presented errors below 7% for the evaluated variables, with R² values above 0.85. Finally, the influence of whey protein denaturation at 60 °C on the stabilities of the two most stable nanoemulsions, according to the optimization process, was observed.Industrial relevanceAmong its many benefits, nanoencapsulation is characterized by increasing the bioavailability of the encapsulated active compound and by the protection that it grants against environmental and processing effects, as micronutrients (for example vitamins) can be susceptible to chemical, enzymatic and/physical instability prior, during and after the processing of food products that contain. One of the techniques studied in recent decades for obtaining nanoemulsions is microfluidization. Microfluidization is a high-energy method that uses high pressure to force the fluid through microchannels that have a specific configuration, emulsifying the fluid by the combined effects of cavitation, shear and impact, thus showing an excellent emulsifying efficiency. However, in food industries the use of microfluidization is not popular and other kind of high shear homogenization are used. In this work, the development of stable emulsions using microfluidization, calls for the use of other types of materials that can provide emulsifying characteristics, such as whey, a compound that is currently one of the main effluents of dairy processes, depending on the type of product.Obtaining nanoemulsions for encapsulation purposes has been studied in many functional products, but to the best of our knowledge, it has not been reported with high-oleic palm oil. This oil contains approximately 50% saturated, 10% di-unsaturated and 40% monounsaturated fatty acids, with oleic acid in sn-2 position in triacylglycerols. This composition makes palm oil as soluble as olive oil. In addition, high-oleic palm oil (HOPO), in particular, has a high stability because it is an oleic acid-rich oil, which has been introduced to replace trans fats and has presented a healthy alternative to such fats in food formulations and the fried food industry.It is also important to highlight that oleic acid has a range of health benefits, such as a decrease in the total cholesterol, an increase in HDL (high-density lipoprotein) and a decrease in LDL (low-density lipoprotein). Oleic acid also retards the development of heart diseases, promotes the formation of antioxidants in the body and reinforces the integrity of the cell wall. In addition, red palm oil (crude) contributes significant nutritional value because it is rich in β-carotenes, α-tocopherol and tocotorienols, supplying vitamins and provitamins that are important for but not produced by the human body.Finally, this work demonstrates that emulsion drop size does not affect the stability of the nanoemulsion if it formulation is designed. Therefore, the goal of this work was to evaluate the most favorable conditions for the microfluidization, formulation and storage of HOPO nanoemulsions using whey powder to produce stable nanoemulsions.     

微波辅助棕榈油制备生物柴油的研究

用棕桐油和甲醇为原料,KOH为催化剂,利用微波辅助酯交换反应制备生物柴油。考察醇油摩尔比、催化剂用量、反应时间和反应温度对酯交换反应的影响。结果表明,制备生物柴油的最适条件为醇油摩尔比7：1,反应温度50℃,反应时间3min,催化剂用量1．2％。在此反应条件下生物柴油转化率可达93％。经性能比较所得生物柴油主要质量指标达到我国和美国生物柴油质量标准。     

Analysis of a complex mixture of carotenes from oil palm (Elaeis guineensis) fruit extract

A carotene extract from the fruits of the oil palm (Elaeis guineensis) was analysed by HPLC employing a C₃₀ column for better separation efficiency. A multitude of cis-isomers of α-, β- and γ-carotene were separated. Detailed assignment was possible by subjecting pure standards of α-, β- and γ-carotene to isomerisation and comparing spectral data and order of elution to literature data. α- and β-carotene were found to be the most abundant carotenoids comprising 12.3% and 17.9%, respectively, of a (roughly) 30% oil suspension of oil palm carotenes in vegetable oil. A large proportion (about 40%) of α- and β-carotene was in the form of cis-isomers. The γ-carotene content was found to be 0.38% and other carotenes like phytoene, phytofluene, ζ-carotene, lycopene and possibly β-zeacarotene were found as well but were not quantified.     

基于微波预处理油菜籽的压榨油和浸出油理化品质比较

微波预处理油菜籽可显著提高压榨出油率,但压榨后的饼粕中仍残留油脂,可采用浸出法提取饼中残油。为比较压榨油和浸出油的主要理化品质,在2450MHz、800W的微波条件下,分别对油菜籽预处理0～7min,冷却至室温后压榨制油,继而对饼粕中残油用正己烷萃取。结果表明,微波处理时间、压榨和浸出的制油方式对菜籽油酸价、过氧化值、p-茴香胺值、水分含量均有显著影响（P〈0.05）。压榨油和浸出油的酸价、p-茴香胺值随微波时间的延长而增加,过氧化值呈先增加后减少的趋势,浸出油酸价、过氧化值和p-茴香胺值高于压榨油。压榨油水分含量随微波时间的延长而增加,而浸出油的则减少,压榨油水分含量高于浸出油。压榨油和浸出油的色泽（罗维朋比色）随微波时间的延长逐渐变深,浸出油色泽更深;加热试验（至280℃）中压榨油无析出物,而浸出油产生絮状析出物。由此可见基于微波预处理油菜籽的压榨油仅需水洗、过滤或离心分离即可满足国家标准,浸出油则需要进行脱胶、脱酸、脱色等精炼处理。     

棕榈残渣浸出取油工艺的研究

对棕榈果榨油后的残渣进行浸出取油工艺的研究。通过单因素试验研究了物料含水率、浸出时间及浸出级数对棕榈残渣浸出取油的影响,并采用正交试验确定最佳浸出工艺条件。结果表明,在浸出温度55℃、液料比6∶1、物料含水率9.72%、每次浸出时间40 min、浸出级数4级的条件下,棕榈残渣中残油达到最低,为0.31%。     

棕榈油的酸催化水解工艺研究

以棕榈油为原料进行常压酸催化水解工艺研究。考察了反应时间、反应温度、催化剂用量、油水质量比及乳化剂用量对棕榈油水解反应的影响,得出棕榈油一次酸催化水解的最佳反应条件:反应时间7 h,反应温度100℃,催化剂浓硫酸用量7.5%,油水质量比1∶1,乳化剂磺酸用量0.5%;在最佳反应条件下棕榈油水解产物酸值(KOH)为192.77 mg/g,水解率达到91.96%。并研究出一套循环水解的工艺流程,实现油脂水解产物的循环利用,提高了水相中甘油的含量。     

Determination of oil palm fruit phenolic compounds and their antioxidant activities using spectrophotometric methods

There is scarce information on the phenolics of oil palm fruits (Elaeis guineensis). In this study, phenolics were extracted from oil palm fruits and analysed using spectrophotometry for information on the different types of palm phenolics and their antioxidative activities. Analyses of the total phenolic content (TPC), total flavonoid content (TFC), o‐diphenols index, hydroxycinnamic acid index, flavonols index and phenol index showed ranges between 5.64 and 83.97 g L^?1 gallic acid equivalent (GAE), 0.31–7.53 g L^?1 catechin equivalent, 4.90–93.20 g L^?1 GAE, 23.74–77.46 g L^?1 ferulic acid equivalent, 3.62–95.33 g L^?1 rutin equivalent and 15.90–247.22 g L^?1 GAE, respectively. The antioxidant assay, 2,2‐diphenyl‐2‐picrylhydrazyl radical scavenging assay, showed antioxidative activities in all the extracts with results ranging from 4.41 to 61.98 g L^?1 trolox equivalent. The high antioxidant activities of the oil palm fruit phenolics were also found to increase with increasing TPC and TFC.     

Improvement of palm oil and sunflower oil blends by enzymatic interestrification

Palm oil (PO) and sunflower oil (SFO) blends with varying proportions were subjected to enzymatic interesterification (EIE) using a 1,3‐specific immobilised lipase. The interesterified blends were evaluated for their slip melting point (SMP), solid fat content (SFC) at 10–40 °C, p‐anisidine value, peroxide value, free fatty acids (FFA), induction period of oxidation at 110 °C (IP110) and composition of fatty acids by gas chromatography. Under EIE treatment, the blends of PO and SFO in different proportions (20:80, 40:60, 50:50, 60:40 and 80:20) had saturated and unsaturated fatty acid content in the range of 37.6–52.0% and 48.0–62.4%, respectively. The blends showed a considerable reduction in their SFC, SMP, peroxide value and oxidative stability at 110 °C, but presented increase in FFA and p‐anisidine value. The optimum condition for minimising the fatty acid in oil was obtained, at 64 °C, using 8.9% enzyme and 3 h reaction time.     

分子蒸馏精制棕榈油甘油二酯工艺研究

利用分子蒸馏小试装置研究了分离较高纯度棕榈油甘油二酯的生产工艺。利用Novozym 435脂肪酶在无溶剂体系下甘油解棕榈油,制备甘油二酯含量大于50%的酰基甘油混合物,采用两级分子蒸馏进行精制,并研究了二级分子蒸馏温度、刮膜转速、进料速率对甘油二酯纯度的影响。结果表明:在二级分子蒸馏真空度0.1 Pa、蒸馏温度230℃、刮膜转速300 r/min、进料速率4 m L/min的条件下,得到了纯度达到80%左右、得率达到50%左右的棕榈油甘油二酯产品。     

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.     

Production of lipase‐catalyzed solid fat from mustard oil and palm stearin with linoleic acid by response surface methodology

BACKGROUND: Solid fat was produced from mustard oil and palm stearin through lipase‐catalyzed reaction, in which linoleic acid was intentionally incorporated. For optimizing the reaction condition of melting point and ω6/ω3 fatty acids, response surface methodology (RSM) was employed with three reaction variables such as substrate mole ratio of mustard oil (MO) to palm stearin (PS) (X₁), reaction temperature (X₂) and reaction time (X₃). RESULTS: The predictive model for melting point of solid fat was adequate and reproducible due to no significant lack of fit (P = 0.0764), P‐value (0.0037) of the model, and satisfactory level of coefficient of determination (R² = 0.92). For the ω6/ω3 ratio model, R² and P‐value were 0.89 and 0.0132, respectively, but lack of fit was significant (P = 0.0389). The melting point of the produced solid fat was affected by substrate mole ratio, whereas reaction temperature and time had no significant effect. The ω6/ω3 ratio of solid fat was influenced by substrate mole ratio and reaction temperature but not by reaction time. Based on ridge analysis, lower ω6/ω3 ratio was predicted by decreasing substrate mole ratio and reaction time, and by increasing reaction temperature. CONCLUSIONS: For producing solid fat with a specific melting point of 34.57 °C, a combination of 1:2 (X₁), 65.17 °C (X₂) and 21.46 h (X₃) was optimized, and the optimization was confirmed under the same reaction conditions. The solid fat contained palmitic (37.8%), linoleic (24.8%), oleic (21.3%), and erucic acid (9.7%), and its solid fat content was 30.3% and 10.3% at 20 and 30 °C, respectively. Copyright © 2009 Society of Chemical Industry     

Production of trans‐free margarine stock by enzymatic interesterification of rice bran oil,palm stearin and coconut oil

BACKGROUND: Trans‐free interesterified fat was produced for possible usage as a spreadable margarine stock. Rice bran oil, palm stearin and coconut oil were used as substrates for lipase‐catalyzed reaction. RESULTS: After interesterification, 137–150 g kg^?1 medium‐chain fatty acid was incorporated into the triacylglycerol (TAG) of the interesterified fats. Solid fat contents at 25 °C were 15.5–34.2%, and slip melting point ranged from 27.5 to 34.3 °C. POP and PPP (β‐tending TAG) in palm stearin decreased after interesterification. X‐ray diffraction analysis demonstrated that the interesterified fats contained mostly β′ polymorphic forms, which is a desirable property for margarines. CONCLUSIONS: The interesterified fats showed desirable physical properties and suitable crystal form (β′ polymorph) for possible use as a spreadable margarine stock. Therefore, our result suggested that the interesterified fat without trans fatty acid could be used as an alternative to partially hydrogenated fat. Copyright © 2010 Society of Chemical Industry     

The absence of endogenous lipase from oil palm mesocarp

Oil palm (Elaeis guineensis Jacq.) fruit mesocarp had higher levels of free fatty acids at the ends of the fruits than in the middle, and microscopy showed that yeasts penetrate the mesocarp via the scars at each end. Very low levels of esterase activity, probably not due to a lipase, were detected in mesocarp extracts by using 4-methyl umbelliferone esters as substrates, but no activity against triacylglycerols could be found. In bruising and storage trials, the only variable that correlated (P<0.01) with free fatty acid level was yeast and mould count. It is concluded that yeasts and moulds are the source of lipolytic activity in oil palm mesocarp, and there is no evidence for an endogenous lipase.     

米曲霉Y6产中性蛋白酶和内切葡聚糖酶的研究

以提高中性蛋白酶和内切葡聚糖酶酶活为目的,优化了米曲霉Y6的制曲工艺。在单因素的试验基础上,采用正交试验优化的米曲霉Y6中性蛋白酶的最佳制曲工艺参数为温度30℃,接种量1.0×107个孢子/g干基,培养时间42h,含水量80%,其酶活达到3637U/g;内切葡聚糖酶的最佳制曲工艺参数为温度为30℃,接种量0.25×107个孢子/g干基,培养时间48h,含水量100%,其酶活达到810U/g。     

The isolation of volatile oil from coriander fruit by steam distillation

The isolation of the essential oil of coriander fruit by steam distillation is described. The chemical composition of the oil was investigated by means of gas-liquid chromatography, column chromatography and coupled gas chromatography-mass spectrometry. The 18 most important components were identified and quantified.