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Lipid oxidation is important to food manufacturers especially when they increase unsaturated lipids in their products to improve nutritional profiles. Unfortunately, the number of antioxidants available to food manufacturers to control oxidative rancidity is limited and the approval of new antioxidants is unlikely due to economic barriers in obtaining government approval for new food additives. Therefore, new antioxidant technologies are needed for food oils. This paper reviews the current knowledge of lipid oxidation in foods with emphasis on how physical properties of food systems impact oxidation chemistry. In particular, the role of association colloids in bulk oils on lipid oxidation chemistry is discussed in an attempt to understand mechanisms of oxidation. Increasing the understanding of how physical properties impact lipid oxidation could lead to the development of novel antioxidant technologies that not only protect the oil against oxidation and increase shelf-life but also allow food manufacturers to include more nutritionally beneficial fatty acids in their products.

Structuring liquid oils has become an active area of research in the past decade, mainly due to pressures to reduce saturated fat intake and eliminate trans fats from our diets. However, replacing hard fats with liquid oil can lead to major changes in the quality of food products. Recent strategies to impart solid-fat functionality to liquid oils include the addition of unusual compounds to oil, leading to its gelation. These include small-molecule organogelators such as phytosterols and 12-hydroxystearic acid, which self-assemble into crystalline fibers which trap oil. Other crystalline additives include waxes, ceramides, monoacylglycerides, and other surfactants. Recently, the polymer ethyl cellulose was reported to form a polymer gel in triacylglyceride (TAG) oils. Other non-conventional strategies also include the formation of protein-stabilized cellular solids with oil trapped within the cells. In this review, we summarize the research on each one of these components in order to provide a comprehensive overview of the state of the area in oleogel research and provide future perspectives.

Many waxes including plant waxes and animal waxes were evaluated for the gelation ability toward soybean oil (SBO) and compared with hydrogenated vegetable oils, petroleum waxes and commercial non-edible gelling agents to understand factors affecting the gelation ability of a gelator. Sunflower wax (SW) showed the most promising results and all SW samples from three different suppliers could make a gel with concentrations as low as 0.5 wt%. Candelilla wax and rice bran wax also showed good gelation properties, which, however, varied with different suppliers. Gelation ability of a wax is significantly dependant on its purity and detailed composition. A wax ester with longer alkyl chains has significantly better gelation ability toward SBO than that with shorter alkyl chains indicating that the chain length of a component in a wax such as wax ester is an important factor for gelation ability. The SW–SBO organogel showed increased melting point with increased SW content, showing the melting point range from about 47 to 65 °C with 0.5–10 wt% SW. The effects of cooling rate on crystal size and firmness of a gel were investigated. The dependence of firmness on cooling rate was so significant that the desired texture of an organogel could be achieved by controlling the cooling rate in addition to controlling the amount of gelling agent. This research reveals that a small amount of food grade plant waxes including SW may replace a large amount of the hardstock containing trans-fat or saturated fat.

Industrial wastewater has a considerable environmental impact on the environment. Wastewater from oil refining, which has been removed from oils, grease, detergents, and phenol, is one of the effluents which present a particular danger to the environment. In this study, we used bio-coagulants to reduce pollution by coagulation-flocculation of wastewater from oil refining. This study shows an exciting contribution to the valuation of natural resources such as cacti in Morocco. Bio-coagulant is a novel biodegradable organic flocculant extracted from prickly pear juice. The results showed that the extract’s optimal dosage varies between 10 and 40 mg/L, leading to removal yields ranging from 40 to 90%. Global data, based on the use of cactus juice as a coagulant in coagulation-flocculation processes for the treatment of oil refinery wastewater, showed removal percentages between 86 and 99%, 62 and 76%, and 67 and 95% for turbidity, COD, and discoloration, respectively. Indeed, bio-flocculants are effective for treating process wastewater on a laboratory scale using a 50-L pilot with the lowest cost. However, more research is needed to explore the scaling of the laboratory scale to well-illustrate the various parameters that drive practical application on a large scale. The bio-flocculant used is a new biodegradable natural product which does not affect the environment compared to other synthetic flocculants. It is of definite interest for the treatment of waste water rich in oils and greases producing less sludge.

An optimized procedure for extraction of total and non-polar lipids from microalgae is proposed. The effects of solvent, pretreatment (lyophilization, inactivation of lipases, and addition of antioxidants) and cell-disruption (liquid nitrogen, sonication, and bead beating) on total lipid content, lipid class, and fatty acid composition were examined. Chloroform–methanol 1:1 was shown to be the best solvent mixture for extraction of total lipids from microalgae. When performing this extraction, lyophilized algae can be used, no pretreatment with isopropanol to inactivate the lipases is needed and addition of antioxidants is not necessary. Furthermore, cell-disruption is not essential, although in that case two extractions must be performed in series to ensure that, irrespective of the microalgal species, all lipids are extracted. Determination of non-polar lipid content should be performed by separation of the total lipid extract on an SPE column. Extraction using petroleum ether is only appropriate when a bead beater is used for pretreatment.

Over the years, there has been a steady stream of publications on the influence that minor components and additives have on the physical properties of fat continuous systems. These have been reviewed here. Both indigenous and added components are taken into account. The various materials have been discussed, ranging from partial glycerides and phospholipids to esterified sugars and polyols. Within the publications in this area, the (sub-)micron effects that these minor components have on nucleation, crystal growth, morphology, heat capacity and polymorphic stability have been described and discussed and, sometimes, explained. Similarly, the effects on a macroscopic level, such as visual aspects, melting profiles, post-hardening and rheology have been the subject of research. Although limited compositional information, especially of additives, hinders appropriate discussions of the relevant mechanisms, some generic guidelines as to what type and strength of effect can be expected have been derived. As a general rule, a more significant influence is observed when the acyl group of the minor component (where present) is similar to those present in the fat itself. Additives may have different effects depending on the fat they are added to, their concentration and the temperature, especially with increasing undercooling (which typically reduces the effect of additives).

The analysis of statistical data showed that a large amount of plant waste is generated annually in oil and fat production plants, which must be processed and reused. The paper analyzes the problems of reusing sunflower oil production waste, which is characterized by a relatively high energy value: 1 ton of plant waste is equivalent to 0.625 tons of conventional fuel. According to the mathematical estimation, the actual total amount of impurities is 7.29%, in which major impurities constitute 25.7%. Studies have shown a high probability of oil – containing impurities – 37.25%. Therefore, it is recommended to process such impurities into fuel briquettes and technical oil to increase the profitability of sunflower oil production. For example, at the annual load of technological equipment of the Melitopol Oil Extraction Plant, in 250 days, at a daily processing capacity of 550 t˙day-1, an annual profit of 560,000 EUR is obtainable from the sunflower grain impurities processed into fuel and technical oil.

This review paper is focused on the relative antioxidant activities of tocopherols and tocotrienols in oils and fats and certain food systems. α-Tocopherol generally showed better antioxidant activity than γ-tocopherol in fats and oils, but at higher concentrations γ-tocopherol was found to be a more active antioxidant. The results of studies on the optimum antioxidant concentrations of tocopherols in oils and fats indicated that the optimal level for α-tocopherol is usually lower than other tocopherols, meaning less α-tocopherol is needed for maximum antioxidant protection. There are comparatively very few studies related to the antioxidant activities of tocotrienols in oils and fats. It has been stated that generally γ-tocotrienol has higher antioxidant effect than α-tocotrienol, and tocotrienols may be better antioxidants than their corresponding tocopherols in certain oils and fats systems. Studies on the antioxidant activity of various tocopherols in food systems are varied and cannot be uniformly evaluated because experiments have generally focused on different foods and used various methods for the detection of antioxidant activities. Depending on the food system, in certain cases tocopherols were better antioxidants than synthetic antioxidants such as butylhydroxy toluene (BHT) or butylhydroxy anisole (BHA). However, in certain other food systems the synthetic antioxidants were more effective to increase the shelf life and the stability of foods than those containing tocopherols.

As a renewable alternative to fossil fuels, the industrial production of biodiesel urgently requires the development of efficient and recyclable solid base catalysts. In this study, the physicochemical properties and catalytic performance differences between MgO/Na[sub.2]CO[sub.3] and MgO/K[sub.2]CO[sub.3] catalysts were systematically compared using soybean oil as the raw material. By regulating the calcination temperature (500–700 °C), alcohol-to-oil ratio (3:1–24:1), and metal carbonate loading (10–50%), combined with N[sub.2] adsorption–desorption, CO[sub.2]-TPD, XRD, SEM-EDS, and cycling experiments, the regulatory mechanisms of the ionic radius differences between sodium and potassium on the catalyst structure and performance were revealed. The results showed that MgO/Na[sub.2]CO[sub.3]-600 °C achieved a FAME yield of 97.5% under optimal conditions, which was 1.7% higher than MgO/K[sub.2]CO[sub.3]-600 °C (95.8%); this was attributed to its higher specific surface area (148.6 m[sup.2]/g vs. 126.3 m[sup.2]/g), homogeneous mesoporous structure, and strong basic site density. In addition, the cycle stability of MgO/K[sub.2]CO[sub.3] was significantly lower, retaining only 65.2% of the yield after five cycles, while that of MgO/Na[sub.2]CO[sub.3] was 88.2%. This stability difference stems from the disparity in their solubility in the reaction system. K[sub.2]CO[sub.3] has a higher solubility in methanol (3.25 g/100 g at 60 °C compared to 1.15 g/100 g for Na[sub.2]CO[sub.3]), which is also reflected in the ion leaching rate (27.7% for K[sup.+] versus 18.9% for Na[sup.+]). This study confirms that Na[sup.+] incorporation into the MgO lattice can optimize the distribution of active sites. Although K[sup.+] surface enrichment can enhance structural stability, the higher leaching rate leads to a rapid decline in catalyst activity, providing a theoretical basis for balancing catalyst activity and durability in sustainable biodiesel production.