Precision Processing for Value-Added Fats and Oils

Lipids are key compounds in foods and provide energy and nutrients to the body. They are carriers of aroma and flavor compounds and contribute to structure and texture. Nutritional research has shown that positive effects on human health are derived from the intake of specific lipids. Similarly, food science research has shown that food matrix design benefits from having tailored lipid fractions with specific functions such as melting profiles, crystal structures, and oil-binding capacities. Minor constituents such as polar lipids or waxes also have valuable functional properties such as the ability to stabilize interfaces, facilitate spreadability, provide barriers, or act as organogelators. Coupled with the emergence of new feedstocks such as new plants, microbes, or insects, this has fueled a renewed interest in designing efficient, effective, and environmentally friendly processes to extract and fractionate lipids from feedstocks. Such precision-processing approaches are intended to yield not just bulk oils and fats but also specialty lipids with tailored properties. In this review article, we discuss the extraction and fractionation approaches used to obtain lipid fractions from plants, animals, or microbial fermentation, discuss their properties and functionalities, and highlight process design approaches, with a focus on sustainable extraction technologies. Recent advances in the three main steps in obtaining food lipids are highlighted: (a) crude oil manufacture; (b) refinement; and (c) fractionization. Finally, two case studies of specialty ingredients derived from such precision-processing approaches are presented.

A review on preparation and application of low-calorie structured lipids in food system

Low-calorie structured lipids are an advanced form of functional lipids made by changing the position of fatty acids attached to the glycerol backbone. The main reason for their production is to get nutraceutical lipids. Different methods are used to synthesize low-calorie structured lipids, like chemical or enzymatic methods. Initially, these lipids are prepared by using chemical methods. Synthesis of low-calorie structured lipids using enzymes is now in demand due to several advantages like good catalytic efficiency, environmentally friendly, and moderate reaction conditions. Enzymatic interesterification is mostly used in industries to make modified lipids like low-calorie structured lipids, human milk substitutes, cocoa butter equivalents, margarine, and shortenings. This review summarizes the synthesis, uses and clinical applications of modified lipids in food systems.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-024-01689-8.

Chemical and physical properties of fats produced by chemical interesterification of tallow with vegetable oils

This study aims at manufacturing structured lipids by chemical interesterification (CI) of beef tallow with corn, canola and safflower oils individually at various tallow blend ratios (60, 70, 80%) and catalyst concentrations (0.75, 0.875, 1%). Several physical and chemical properties of interesterified products were determined and data were analyzed using univariate and multivariate statistical techniques. Interesterified lipids were more spreadable and showed plastic behavior due to their lower consistency and solid fat contents. Decreases in melting points to a temperature range of 26.5-45.5 °C regardless of oil type were observed. Interesterified fats displayed mostly β’ and β’+β crystal forms. The CI of tallow did not result in the formation of significant amounts of trans-fatty acids. Samples interesterified with corn oil had lower free fatty acid contents (1.87-3.9%) and higher oxidation induction times (3.82-12.25h) than other lipids. Therefore, fats containing corn oil-tallow could be used in the baking industry due to their potentially good aeration properties and smooth texture.

Tailoring the Structure of Lipids, Oleogels and Fat Replacers by Different Approaches for Solving the Trans-Fat Issue-A Review

The issue of the adverse effects of trans-fatty acids has become more transparent in recent years due to researched evidence of their link with coronary diseases, obesity or type 2 diabetes. Apart from conventional techniques for lipid structuring, novel nonconventional approaches for the same matter, such as enzymatic interesterification, genetic modification, oleogelation or using components from nonlipid origins such as fat replacers have been proposed, leading to a product with a healthier nutritional profile (low in saturated fats, zero trans fats and high in polyunsaturated fats). However, replacing conventional fat with a structured lipid or with a fat mimetic can alternate some of the technological operations or the food quality impeding consumers' acceptance. In this review, we summarize the research of the different existing methods (including conventional and nonconventional) for tailoring lipids in order to give a concise and critical overview in the field. Specifically, raw materials, methods for their production and the potential of food application, together with the properties of new product formulations, have been discussed. Future perspectives, such as the possibility of bioengineering approaches and the valorization of industrial side streams in the framework of Green Production and Circular Economy in the production of tailored lipids, have been highlighted. Additionally, a schematic diagram classifying conventional and nonconventional techniques is proposed based on the processing steps included in tailored lipid production as a convenient and straightforward tool for research and industry searching for healthy, sustainable and zero trans edible lipid system alternatives.

Evaluation of enzymatic interesterification in structured triacylglycerols preparation: a concise review and prospect

Enzymatic interesterification (EIE) is one of the emerging technologies in the specialty fats industry. EIE has several advantages over the conventional chemical interesterification method, such that the process has higher flexibility and efficiency, is environmentally friendly and the immobilized enzyme can be recycled besides of the lower requirement for substrate's acid value. The physical properties and nutritional qualities of the fats and oils are modified after EIE, depending on the change in the position of fatty acids on the triacylglycerol (TAG) molecules. Evaluation of the interesterification reaction are important and useful in terms of its technological applications. This paper summarizes the conventional methods and the advancement for evaluating EIE processes, e.g., determination of the change in slip melting points, solid fat contents, TAG with equivalent carbon numbers, and sn-2 fatty acid compositions of the end product. Nonetheless, these methods are not comprehensive because during the EIE process, acyl migration occurs. A novel and convenient evaluation model which is based on the fatty acid distribution on the glycerol-backbone is proposed as a perspective. This model can be employed to monitor the interesterification degree and acyl migration during a regiospecific EIE process, which serves as a reaction rule that can be employed to control and optimize the EIE process, thereby producing structured TAG with desired properties.

Difference in microbial community and taste compounds between Mucor-type and Aspergillus-type Douchi during koji-making

Douchi has attracted people's attention because of its unique taste and rich health function. The microbes participated in the koji-making process contribute to taste compounds of Douchi. However, the majority of studies on Douchi focused on their functional components and the microbial community in single type of Douchi during koji-making so far. In the present study, the taste components of Mucor-type and Aspergillus-type Douchi were measured initially and the results showed that the amino acid and organic acid levels as well as the percentage of unsaturated fatty acids in Mucor-type Douchi were significantly higher than those in Aspergillus-type. The investigation of the microbial composition in two types of Douchi showed that Aspergillus, Candida, Meyerozyma and Lecanicillium were shared by >50% of samples during koji-making. Comparison of the microbial community between the two types of Douchi revealed that Meyerozyma and Lecanicillium were the main microbial community with significant difference during the initial stage of koji-making, while Candida was significantly different during the later stage of koji-making. When supplemented with Meyerozyma and Candida in Aspergillus-type Douchi, the level of all amino acid and organic acids as well as the percentage of unsaturated fatty acid was significant improved, which further validated the importance roles of the two microorganisms in enhancing the taste components of Douchi during koji-making. The results provide useful information on optimizing the microbial community structure of Douchi during the process of koji-making and improving the product quality.