Novel structuring strategies for unsaturated fats – Meeting the zero-trans,zero-saturated fat challenge: A review

Numerous foods acquire their elastic properties (i.e., snap, mouth-feel, and hardness) from the colloidal fat crystal network comprised primarily of trans- and saturated fats. These hardstock fats contribute, along with numerous other factors, to the global epidemics related to metabolic syndrome and cardiovascular disease. A dire need for new technologies capable of structuring unsaturated edible oils, reducing the necessity for trans- and saturated fats, are required. At present, organogels are under-utilized in the food industry but numerous potential organogelators exist including: phytosterols and oryzanols, ceramides, monoglycerides and waxes. When examining these compounds as suitable ingredients for the food industry, they should be food grade, cost effective, have no negative health implications and one should be able to modify their physical properties. This review considers alternatives to colloidal fat crystal networks when structuring unsaturated oils as well as methods to modify their physical properties.     

结构化油脂及其在烘焙产品中的应用研究进展

随着人们生活水平的不断提高,消费者越来越意识到健康与饮食之间的重要性。传统食品专用油脂中高含量饱和脂肪酸/反式脂肪酸的摄入对心血管健康的负面影响已引起人们的广泛关注,为了满足人们对健康烘焙产品的需求,开发零反式、低饱和新型专用油脂成为食品科学研究和工业应用领域中重要的课题。本文基于脂肪在烘焙产品中的作用特性,系统阐述了结构化油脂的结构化方法、结构因子对结构化油脂结构的影响及其在烘焙产品中的应用;研究表明,结构化油脂可应用于面包、蛋糕、松饼和饼干等烘焙产品中,在提供传统食品专用油脂类似的质构和感官特性的同时,以其多不饱和脂肪酸含量高的优势改善了烘焙产品的营养特性。     

Properties of Cookies Made with Natural Wax–Vegetable Oil Organogels

The aim of this study was to examine the feasibility of cookies in which the conventional margarine is replaced with an organogel of vegetable oil (VO) and natural wax. New cookies from VO organogels contain no trans fats and much less saturated fats than cookies made with a conventional margarine. To understand the effects of different kinds of waxes, organogels were prepared from 4 different waxes including sunflower wax (SW), rice bran wax (RBW), beeswax, and candelilla wax and properties of cookie dough and cookie were evaluated. To investigate the effects of different VOs on the properties of cookies, 3 VOs including olive oil, soybean oil and flaxseed oil representing oils rich in oleic acid (18:1), linoleic acid (18:2), and linolenic acid (18:3), respectively, were used. Both the wax and VO significantly affected properties of organogel such as firmness and melting behavior shown in differential scanning calorimetry. The highest firmness of organogel was observed with SW and flaxseed oil. Properties of dough such as hardness and melting behavior were also significantly affected by wax and VO while trends were somewhat different from those for organogels. SW and RBW provided greatest hardnesses to cookie dough. However, hardness, spread factor, and fracturability of cookie containing the wax–VO organogel were not significantly affected by different waxes and VOs. Several cookies made with wax–VO organogels showed similar properties to cookies made with a commercial margarine. Therefore, this study shows the high feasibility of utilization of the organogel technology in real foods such as cookies rich in unsaturated fats.     

Amelioration of nutritional properties of bakery fat using omega-3 fatty acid-rich edible oils: a review

Bakery products have gained prominence in modern diets due to their convenience and accessibility, often serving as staple meals across diverse regions. However, the fats used in these products are rich in saturated fatty acids and often comprise trans fatty acids, which are considered as a major biomarker for non-communicable diseases like cardiovascular disorders, obesity and diabetes. Additionally, these fats lack the essential omega-3 fatty acids, which are widely known for their therapeutic benefits. They play a major role in lowering the risk of cardiovascular diseases, cancer and diabetes. Thus, there is need for incorporating these essential fatty acids into bakery fats. Nevertheless, fortifying food products with polyunsaturated fatty acids (PUFAs) poses several challenges due to their high susceptibility to oxidation. This oxidative deterioration leads to not only the formation of undesirable flavors, but also a loss of nutritional value in the final products. This review focuses on the development of healthier trans-fat-free bakery fat enriched with omega-3 fatty acids and its effect on the physicochemical, functional, sensory and nutritional properties of bakery fats and products. Further, the role of various technologies like physical blending, enzymatic interesterification and encapsulation to improve the stability of PUFA-rich bakery fat is discussed, where microencapsulation emerged as a novel and effective technology to enhance the stability and shelf life. By preventing deteriorative changes, microencapsulation ensures that the nutritional, physicochemical and sensory properties of food products remain intact. Novel modification methods like interesterification and microencapsulation used for developing PUFA-rich bakery fats have a potential to address the health risks occurring due to consumption of bakery fat having higher amount of saturated and trans fatty acids. © 2023 Society of Chemical Industry.     

Oleogels,a promising structured oil for decreasing saturated fatty acid concentrations: Production and food-based applications

Oils and fats are widely used in the food formulations in order to improve nutritional and some quality characteristics of food products. Solid fats produced from oils by hydrogenization, interesterification, and fractionation processes are widely used in different foodstuffs for these aims. In recent years, consumer awareness of relation between diet and health has increased which can cause worry about solid fat including products in terms of their high saturated fatty acid and trans fatty acid contents. Therefore, different attempts have been carried out to find alternative ways to produce solid fat with low saturated fatty acid content. One of the promising ways is using oleogels, structuring oils with oleogelators. In this review, history, raw materials and production methods of the oleogels and their functions in oleogel quality were mentioned. Moreover, studies related with oleogel usage in different products were summarized and positive and negative aspects of oleogel were also mentioned. Considering the results of the related studies, it can be concluded that oleogels can be used in the formulation of bakery products, breakfast spreads, margarines, chocolates and chocolate-derived products and some of the meat products.     

Edible oleogels as solid fat alternatives: Composition and oleogelation mechanism implications

The growing awareness of the adverse health effects of trans-fats and saturated fats are driving researchers to seek healthy alternatives. A promising strategy to structure liquid oil, called oleogelation, has been a subject of great interest. In the development of oleogels, highly unsaturated oils can be structured through different gelation mechanisms by varying structuring agents (e.g., polymeric or low molecular weight oleogelators). Due to their potential to reduce saturated fat in food products while also providing solid texture without changing the oil's chemical composition and nutritional values, oleogels have been introduced into various products (meat, spread, and confectionary) as alternatives to traditional solid fats. However, the shortcomings of oleogels cannot be ignored, such as the softer texture and the poorer plasticity than traditional solid fat. As the physicochemical properties and functionalities of oleogels are highly dependent on their composition and structuring mechanism, it is possible to obtain a product with desirable functionality by choosing a suitable oleogelator or oil phase. Thus, comprehensive and detailed knowledge regarding the role of oleoglarors, oil phase, and oleogelation mechanism on oleogelation is needed. This review primarily focuses on published information within the last decades addressing how the composition and oleogelation mechanism affect the structure and functionality of oleogels and oleogel-based products. The factors affecting the oil gelation are summarized concerning three aspects: (i) oleogelator (chemical composition and molecular structure); (ii) oil phase (TAG composition and minor component); and (iii) oleogelation mechanism. Finally, the future perspectives toward oleogels are highlighted. This review aims to deepen the understanding of oleogelation and the rational design of oleogel-based products.     

Effect of Shear Rate on Crystallisation Phenomena in Olive Oil-Based Organogels

The aim of the present work was the rheological and microstructural analysis of olive oil/mono- and diglycerides/cocoa butter organogels as a potential oil phase of structured food emulsions. Step temperature ramp tests at different shear rates and controlled cooling conditions (5 °C/min) were adopted to evaluate the onset of crystallisation temperature (T _co) and viscosity of different samples. In order to study the crystallisation phenomena potentially occurring in adopted raw materials, a preliminary characterisation was carried out on pure and blended fats (olive oil and/or cocoa butter), evidencing a relevant effect of adopted shear rate on T _co. Afterwards, the influence of mono- and diglycerides on organogelation of either pure or blended fats was investigated, increasing the organogelator from 0.5% (w/w) up to 60% (w/w) and observing the increase of T _co with its concentration from 17.7?±?2.7 °C up to 64.5?±?1.0 °C. Experimental results showed that T _co is only determined by the organogelator concentration, and it does not depend on the shear rate and fat source. On the other hand, sample viscosity depends on both the amount of organogelator and the oil phase composition, increasing with saturated fat concentration. Finally, the obtained results allow the fat to be designed with the desired properties: its crystallisation point and rheology can be predicted on the basis of the amounts of the organogelator and the saturated fats, respectively.     

Oxidative stability of solid fats containing ethylcellulose determined based on the headspace oxygen content

Solid fat was developed by blending fully hydrogenated soybean oil, palm oil, and canola oil, and organogels were prepared using selected solid fats and ethylcellulose. The oxidative stability of organogel was tested at 100 and 180°C using a headspace oxygen assay. Addition of ethylcellulose produced a firmer organogel solid state in selected solid fats ranging from 15.8 to 24.6% saturation at room temperature. Addition of ethylcellulose generally decreased the oxidative stability of organogels prepared using canola oil. The oxidative stability of some organogels made using solid fats changed depending on the concentration of added ethylcellulose (10 or 15%, w/w), and the oxidation temperature. Development of an organogel with a relatively low saturation and a high oxidative stability suitable as a food ingredient is possible.     

Tropical oils: nutritional and scientific issues.

Individually and in combination with other oils, the tropical oils impart into manufactured foods functional properties that appeal to consumers. The use of and/or labeling in the ingredient lists give the impression that these oils are used extensively in commercially processed foods. The estimated daily intake of tropical oils by adult males is slightly more than one fourth of a tablespoon (3.8 g), 75% of which consists of saturated fatty acids. Dietary fats containing saturated fatty acids at the beta-position tend to raise plasma total and LDL-cholesterol, which, of course, contribute to atherosclerosis and coronary heart disease. Health professionals express concern that consumers who choose foods containing tropical oils unknowingly increase their intake of saturated fatty acids. The saturated fatty acid-rich tropical oils, coconut oil, hydrogenated coconut oil, and palm kernel oil, raise cholesterol levels; studies demonstrating this effect are often confounded by a developing essential fatty acid deficiency. Palm oil, an essential fatty acid-sufficient tropical oil, raises plasma cholesterol only when an excess of cholesterol is presented in the diet. The failure of palm oil to elevate blood cholesterol as predicted by the regression equations developed by Keys et al. and Hegsted et al. might be due to the dominant alpha-position location of its constituent saturated fatty acids. If so, the substitution of interesterified artificial fats for palm oil in food formulations, a recommendation of some health professionals, has the potential of raising cholesterol levels. A second rationale addresses prospective roles minor constituents of palm oil might play in health maintenance. This rationale is founded on the following observations. Dietary palm oil does not raise plasma cholesterol. Single fat studies suggests that oils richer in polyunsaturated fatty acid content tend to decrease thrombus formation. Anomalously, palm oil differs from other of the more saturated fats in tending to decrease thrombus formation. Finally, in studies comparing palm oil with other fats and oils, experimental carcinogenesis is enhanced both by vegetable oils richer in linoleic acid content and by more highly saturated animal fats. The carotenoid constituents of red palm oil are potent dietary anticarcinogens. A second group of antioxidants, the tocotrienols, are present in both palm olein and red palm oil. These vitamin E-active constituents are potent suppressors of cholesterol biosynthesis; emerging data point to their anticarcinogenic and antithrombotic activities. This review does not support claims that foods containing palm oil have no place in a prudent diet.     

Analysis of trans fatty acids in deep frying oils by three different approaches

Simulated frying experiments were performed on three different types of oils with French fries as the fried food. Comparison of frying oil samples was then made with their control counterparts (i.e. oil samples heated without food). Three different methods, gas chromatography (GC), attenuated total reflection (ATR) AOCS method Cd 14d-99 and attenuated total reflection negative second derivative absorbance (−2D ATR), were applied to quantify total trans fats. The total trans fats were found to be higher in the frying oil samples as compared to the control samples, which might be due to the presence of a high amount of trans fats in the pre-fried and frozen French fries. In general, the ATR AOCS method Cd 14d-99 produced lower amounts of trans fatty acids and the −2D ATR absorbance method produced higher amounts when compared with those obtained by gas chromatography.     

Acute metabolic responses to butter,margarine, and a monoglyceride gel-structured spread

Cardiovascular and metabolic health concerns have led to interest in development of saturated- and trans fat-free margarines, spreads, and other foods. We have recently characterized a novel monoglyceride gel (MAG GEL) that can structure liquid oil into a semi-plastic solid consistency in the absence of saturated and trans fats. Consumption of this MAG GEL resulted in tempered postprandial metabolic responses compared to those resulting from consumption of a compositionally equivalent but unstructured oil suspension, suggesting a structure-dependent metabolic response. The current study was designed to test the hypothesis that postprandial blood lipid and metabolite responses to MAG GEL would be tempered compared to the responses after ingestion of butter and tub-margarine of equal total fat content. Indeed, blood triglyceride response was tempered in MAG GEL compared to butter, margarine, and unstructured oil trials, all of which produced similar triglyceride responses. The blood free fatty acid, glucose, and insulin responses were not different in MAG GEL compared to butter or margarine trials; and interestingly, there were no differences between butter and margarine trials for any of the metabolic response variables. The MAG GEL is a useful structure for many applications, and produces salubrious postprandial metabolic effects compared to other spreadable fats.     

Chemical interesterification of milkfat and milkfat-corn oil blends

Blending and chemical interesterification of fats have been used to modify physical and chemical properties of natural fats. The objective of this study was to produce binary mixtures of butterfat and corn oil that serve as a base for a tablespread, keeping the desirable organoleptic qualities of butter, yet with higher contents of ω-6 fatty acids. Chemical interesterification was performed to improve butter’s physical properties, such as better spreadability. Liquefied butterfat and corn oil were mixed in different proportions and then chemically interesterified. Butterfat consisted of 66.5% saturated fatty acids, with palmitic acid being predominant. Corn oil had more than 50% of linoleic acid in its composition. Interesterification significantly reduced trisaturated and triunsaturated triacylglycerol contents and increased softening points in all blends. The negative coefficients of the blends from multiple regression of the solid fat content revealed a monotectic interaction between butterfat and corn oil in temperatures ranging from 10 to 35 °C, before and after interesterification.     

The relationship between price, amounts of saturated and trans fats, and nutrient content claims on margarines and oils.

PURPOSE: Modifications to the amount and type of fat in the diet are recommended as strategies to help reduce heart disease risk. Individuals can choose from a variety of margarines and oils to alter their intakes of different types of fats, and nutrient content claims on product labels (e.g., 'low in saturated fat') can help them quickly identify healthful products. However, margarines and oils vary in price. METHODS: To examine the relationship between the price and amounts of saturated and trans fats in margarines and oils, and the relationship between price and the presence of nutrient content claims, price and label information were recorded for margarines (n=229) and oils (n=342) sold in the major supermarkets within the Greater Toronto Area. RESULTS: Linear regression analysis revealed a negative relationship between the price and amounts of saturated fat and trans fats in margarines, but not in oils. Margarines with a nutrient content claim were significantly more expensive than were those without a claim. CONCLUSIONS: The findings for margarines are of particular concern for lower income groups for whom budgetary constraints result in the purchase of lower priced foods, and also raise important questions about the usefulness of nutrient content claims in guiding food selections.     

High pressure crystallization of binary fat blend: A feasibility study

Crystallization mechanism of triglycerides plays an important role in structuring of the plastic fats, such as margarine and shortening. The effects of cooling under high pressure on crystallization and functional properties of a mixture of fully hydrogenated soybean oil and soybean oil (3:7 mass ratio) at 30 °C were investigated and compared against samples crystallized under atmospheric condition. Experiments were conducted using a face-centered central composite design. It is shown that pressure level, initial temperature, and maximum temperature under pressure affect sample's storage modulus, yield stress and percent oil loss. Holding time and pressure pulsing did not significantly influence the properties. Inverse relationships between the mechanical properties and percent oil loss were observed. Presence of crystal seeds in the sample prior to pressurization yielded lipid crystals with different polymorphic properties than those directly crystallized from the melt.Industrial relevanceThe study demonstrates that high pressure processing can improve plasticity and physical properties of fat blends with low saturated fat content. High pressure crystallization is proven to offer better crystallization properties with lower supercooling condition and prevent the need for long hour incubation.     

Effects of Organogel Hardness and Formulation on Acceptance of Frankfurters

Different organogel formulations used as beef fat (BF) replacement (0%, 20%, 40%, 60%, and 80%) were utilized to optimize the mechanical properties of frankfurters. Organogels, made of canola oil (CO), included different concentrations of ethyl cellulose (EC) and sorbitan monostearate (SMS). They consisted of: 8% EC + 1.5% SMS referred to as organogel‐I (OG‐I), 8% EC + 3.0% SMS (OG‐II), and 10% EC + 1.5% SMS (OG‐III), which were found promising in a previous study when used at 100% replacement. Replacement of BF with organogels at all levels could bring down the very high hardness values (texture profile analysis and sensory) of frankfurters prepared using CO by itself, relative to the BF control. OG‐I and OG‐II quantity had no significant effect on hardness and springiness, being similar in many cases to the BF and lower than the CO control. Shear force values of all organogel treatments were not significantly different from one another, and were between the BF and CO controls. Smokehouse yield showed a pattern of decreasing losses with increasing organogel replacement level. Sensory analysis revealed that using CO by itself significantly increased hardness, but structuring the oil (via organogelation), brought it down to the BF control value in all OG‐I and OG‐II formulations. Juiciness was significantly reduced by using liquid oil but increased with raising the amount of organogels. Oiliness sensation increased with higher organogel substitution and was actually higher than the beef control. The study demonstrates the potential use of vegetable oil structuring in replacing the more saturated BF in emulsion‐type meat products.     

Crystal network for edible oil organogels: Possibilities and limitations of the fatty acid and fatty alcohol systems

The textural and structural properties of organogels made by structuring liquid oil with mixtures of stearic acid (octadecanoic acid) and stearyl alcohol (octadecanol) have been studied. Optical, rheological and X-ray diffraction measurements have been used to investigate the influence of temperature, time and composition on the pseudo-binary system. The aim of these experiments is to relate the observed macroscopic behaviour of the organogels to the microscopic molecular ordering within the crystals that form a network. Oscillating strain measurements have been performed on mixtures with various acid to alcohol ratios. A synergetic effect in structuring was obtained by applying a 3:7 (acid:alcohol) ratio. Hardness and elastic modulus were significantly higher compared to samples with other ratios, at the same overall structurant concentration. Microscopy showed that the crystal habit of the structurant strongly depends on the composition of the mixture. X-ray diffraction experiments, which show that mixed crystals are formed when structurant mixtures are used, confirmed this result. The observed behaviour of the elastic modulus is likely the result of the difference in the microstructure of the interlinked crystals.     

Towards a multidisciplinary approach to structuring in reduced saturated fat‐based systems – a review

Although many food products are essentially emulsions, interest in the structuring of oil‐continuous emulsions (and in specific cases water‐continuous emulsions) is intense, particularly to meet the continuing challenge of reducing the degree of saturates in food systems. Consequently, it is necessary to observe the effects of structurants and to examine their impacts on current food systems. This is especially the case where novel structuring materials are used to wholly or partially replace traditional structurants. A multidisciplinary approach is discussed encompassing traditional and novel mechanisms considered able to structure within low saturated fat‐based systems and which in themselves could also have emulsification properties. The presence of interfacial compositions as in emulsions requires a crucial understanding of the interactions within these compositions for the creation of building blocks in oil or fat structuring. Where a co‐surfactant structure may be used, together with novel structurants, for example, wax esters, phytosterols, it is necessary to understand how these may influence interfacial film thickness, strength and flexibility. Understanding how to measure mechanical visco‐elastic properties of structurant interactions both in model and real time dynamic measurements will be necessary to account for diffusion, orientation and self‐assembly mechanisms. This review discusses combining traditional techniques with novel structurant technology; developing and validating dynamic measurement techniques; and investigation of real systems as opposed to purely model systems.     

蛋白基乳液模板法构建油凝胶的研究进展

传统塑性脂肪带来健康问题,液态油固化成为构建零反式、低饱和脂肪酸塑性脂肪替代品的新策略。蛋白质是优质的食品营养组分,是来源广泛的可再生资源,具有独特的界面特性。为扩大蛋白资源的应用范围及促进功能性油脂的开发,对蛋白质的结构化及蛋白基乳液模板法构建油凝胶(结构化油脂)研究进展进行了综述,同时介绍了蛋白基乳液模板法构建的油凝胶的应用。蛋白质在一定条件下可作为凝胶剂固化液态油;蛋白基乳液模板法构建油凝胶具有安全性高、对环境污染小等优点。采用蛋白基乳液模板法构建的油凝胶可应用于替代传统塑性脂肪、荷载生物活性成分方面。     

HEALTH PROMOTING CONSTITUENTS IN PLANT DERIVED EDIBLE OILS

Of all the edible oils, only that produced from olives has had its health attributes studied in detail. For maximum nutritional benefit, an edible oil should contain minimal levels of saturated fats, especially lauric and myristic acids and minimal levels of trans fatty acids. If the oils are not to be heated repeatedly and if they contain high levels of antioxidants, they should contain omega-3 and possibly omega-6 polyunsaturated fatty acids. The fatty acid profile should be dominated by monounsaturated fatty acids. Secondary products which act as antioxidants including polyphenols, proanthocyanidins, tocopherols and carotenoids increase the shelf-life of oils, reportedly reduce cardiovascular disease and provide some anticarcinogenic properties. More research is also required, but there is evidence that phytosterols and squalene are also beneficial components of edible oils. Selection and breeding can be used to increase the desirable components of edible oils. Geographic, culture and environmental factors can influence the properties of the oil produced by crops, and methods of processing can greatly reduce the levels of health promoting components. Despite the current anti-GMO sentiments, biotechnology should be used both in the development of plant cultivars which produce nutritional oils and in processing to maximize the desirable components.