European Journal of Lipid Science and Technology

Castor oil is, as many other plant oils, a very valuable renewable resource for the chemical industry. This review article provides an overview on this specialty oil, covering its production and properties. More importantly, the preparation, properties and major application possibilities of chemical derivatives of castor oil are highlighted. Our discussion focuses on application possibilities of castor oil and its derivatives for the synthesis of renewable monomers and polymers. An overview of recent developments in this field is provided and selected examples are discussed in detail, including the preparation and characterization of castor oil‐derived polyurethanes, polyesters and polyamides.

The Malaysian oil palm industry is one of the most highly organised sectors of any national agriculture system of the world. Today, though, the focus has shifted to how well agriculture also meets universally accepted standards of sustainability. This paper highlights the development of oil palm cultivation and responsible farming practices in Malaysia, the world's largest producer of palm oil. The oil palm has had a natural head start in fulfilling sustainability indicators due to its plant physiology of high productivity and efficient carbon assimilation. Over the last 50 years, R&D activities and technological advances have helped raise yields and reduce inputs, thereby maximising oil production from a smaller land area than used for other food crops. Palm oil is now a major source of sustainable and renewable raw material for the world's food, oleochemical and biofuel industries. Involvement in cultivation or downstream activities has uplifted the quality of life of people, a key plank of the sustainability platform. In particular, this has helped alleviate poverty among landless farmers in Malaysia. Industry players have recently joined hands with other stakeholders to pursue certification of sustainably produced palm oil with full traceability. Also being explored are measures to conserve forests with high value and the wildlife population.

Autoxidation in food and biological systems is responsible for a multitude of adverse effects and implications in human health as well as in food stability and preservation. Antioxidants play a major role in preventing or delaying autoxidation and have attracted much attention as food stabilizers, dietary supplements and natural health products. Both synthetic and natural antioxidants are widely used in food products and an ever increasing number of research papers have appeared in the recent literature on the discovery and application of natural antioxidants and their therapeutic use in inhibiting a myriad of diseases. However, some common synthetic antioxidants have also become controversial due to their potential adverse effects on health. This overview provides the latest developments about novel antioxidants, particularly phenolic derivatives, peptides/protein hydrolysates, phospholipids and polysaccharides, and their role in food quality preservation and human health promotion.

The depletion of the world's crude oil reserve, increasing crude oil prices, and issues related to conservation have brought about renewed interest in the use of bio‐based materials. Emphasis on the development of renewable, biodegradable, and environmentally friendly industrial fluids, such as lubricants, has resulted in the widespread use of natural oils and fats for non‐edible purposes. In this study, we have reviewed the available literature and recently published data related to bio‐based raw materials and the chemical modifications of raw materials. Additionally, we have analyzed the impacts and benefits of the use of bio‐based raw materials as functional fluids or biolubricants. The term biolubricants applies to all lubricants, which are both rapidly biodegradable and non‐toxic to humans and other living organisms, especially in aquatic environments. Biodegradability provides an indication of the persistence of the substance in the environment and is the yardstick for assessing the eco‐friendliness of substances. Scientists are discovering economical and safe ways to improve the properties of biolubricants, such as increasing their poor oxidative stability and decreasing high pour points. “Green” biolubricants must be used for all applications where there is an environmental risk.

The oxidative stability of vegetable oils is determined by their fatty acid composition and antioxidants, mainly tocopherols but also other non‐saponifiable constituents. The effect of fatty acids on stability depends mainly on their degree of unsaturation and, to a lesser degree, on the position of the unsaturated functions within the triacylglycerol molecule. Vegetable oils contain tocopherols and tocotrienols, especially α‐ and γ‐tocopherols, as their main antioxidants. The antioxidant behavior of tocopherols represents a complex phenomenon as they are efficient antioxidants at low concentrations but they gradually lose efficacy as their concentrations in the vegetable oils increase. The “loss of efficacy” of tocopherols, sometimes referred to as a “pro‐oxidant effect”, is witnessed by an increase in the rate of oxidation during the induction period, despite elongation of this phase. The phenomenon is much obvious for α‐tocopherol, but is also evident for other tocopherols. In agreement with nature's wisdom, the tocopherol levels in vegetable oils seem to be close to the optimal levels needed for the stabilization of these oils. The presence of other antioxidants in the oils, e.g. carotenoids, phenolic compounds, and Maillard reaction products, may synergize with tocopherols and minimize this loss of efficacy.

The oligomerization of glycerol to preferentially di‐ and triglycerol is reviewed, with primary focus on the use of heterogeneous acidic and basic catalysts. Low molecular‐weight oligomers have found a wide field of applications in cosmetics, food industry and polymer production. The growing market intensified research work on the selective catalytic oligomerization of glycerol. Performing the reaction of glycerol in the presence of microporous and mesoporous solid catalysts aims at exerting shape‐selective effects on the reaction, suppressing the abundant formation of cyclic isomers and cutting further polymerization of the target products. Enhanced selectivity to diglycerol is observed over some type of catalysts, but the solids suffer from leaching of active alkaline cations from the solid, severe deterioration of crystallinity of zeolites and even dissolution of the solids in the hot glycerol during batch reaction at temperatures in the range of 240–260°C. In those cases it is difficult to separate homogeneous and heterogenous reaction routes, and the shape‐selective effects are levelled off. The oligomerization is a consecutive reaction, and complete conversion of glycerol favours formation of high molecular‐weight glycerol oligo‐ and polymers. To achieve maximum yield of diglycerol, the reaction has to be interrupted at glycerol conversions of ca. 50%. Alternative reaction engineering is required to overcome the inherent disadvantages of a batch reaction. Examples will be given for a selective glycerol oligomerization under reduced pressure in a so‐called fall‐film reactor using super‐acidic polymers as catalysts.