Search

Oleaginous yeasts offer a promising sustainable alternative for producing edible lipids, potentially replacing animal and unsustainable plant fats and oils. In this study, we screened 11 oleaginous yeast species for their lipid profiles and identified Apiotrichum brassicae as the most promising candidate due to its versatility across different growth media. A. brassicae grown in a dairy side stream produced lipids with a composition most similar to cocoa butter, but the stearic acid and linoleic acid content varied greatly when grown on different substrates. We visualised the formation of lipid droplets by digital holotomography. Pilot-scale production was followed by enzymatic and ultrasonic treatment of biomass and heptane/ethanol extraction. The fatty acid (FA) and triacylglycerol (TAG) composition, thermal behaviour, and solid fat content of A. brassicae lipids was compared to benchmarks such as beef fat, cocoa butter, palm oil and milk fat. The FA profile of the A. brassicae lipids shares the same types of fatty acids with cocoa butter, beef fat and palm oil, however concentrations differ resulting in a lower content of saturated FAs. This increased the proportion of unsaturated TAGs, reducing the melting and crystallisation temperatures and the solid fat content. The microbial lipids contained the major TAGs of cocoa butter at similar ratios, resulting in a comparable melting peak and crystallisation peaks similar to the low-melting groups of beef fat and palm oil. Fractionation has the potential to produce beef fat, cocoa butter or palm oil equivalents with desired techno-functional properties. This study demonstrates the potential of A. brassicae to produce tailored lipid profiles for various food applications through strain and process engineering or downstream processing., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Cryogel particles were obtained by freeze-drying and grinding hydrogel monoliths made from 20 % (w/w) whey protein isolate (WP) suspensions prepared at different pH (pH 4.8, 5.7, and 7.0). The microstructure, porosity, and density of the cryogels were strongly affected by the starting pH of the suspension. At pH 4.8, corresponding to the isoelectric point, proteins assumed a globular form leading to a cryogel with the highest porosity and lowest density compared to those formed at higher pH values (5.7 and 7.0). Such morphological differences accounted for different oil structuring capabilities. When mixed with oil, the cryogel particles formed at the pI were capable of entrapping larger quantities of oil (∼63 % w/w) than those obtained distant from the pI (∼47 %, w/w), forming a spreadable material. In this system, as confirmed by confocal microscopy, WP particles were evenly distributed in oil forming a network connected by capillary bridges and surface hydrophilic interactions. Thus, the mixture of sunflower oil with cryogel particles formed at the pI allowed to obtain an oleogel, exploitable for fat replacement, as confirmed by the preparation of a cocoa spread prototype. Results highlighted the critical impact of protein hydrogel structure in determining the ability of the cryogel particles thereof to entrap oil and tune the oleogel characteristics. The potentialities of this innovative material as ingredient of low saturated fat food products were also demonstrated., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Oleogelation is an alternative oil structuring route to formulate (semi-)solid fats with a reduced amount of saturated fats. Monoglycerides have been identified as effective gelators; however, their application potential can be limited due to challenges regarding mechanical strength and long-term stability. Therefore, the formulation of hybrid fat blends is a promising way to improve the functionality of oleogels. This research focuses on the interaction between mono- and triglycerides (MAGs and TAGs) in hybrid oleogels. A total gelator concentration of 10% ( w / w ) with changing MAGs-TAGs ratios (increase by 25% on a molar basis; M0-T100, M25-T75, M50-T50, M75-T25, M100-T0) was used. First, the oleogels were produced without shear to unravel the crystallization behavior (DSC, SAXS, WAXS). Next, the oleogels were crystallized with shear to assess the interactions between MAGs and TAGs on macroscale properties (rigidity, oil binding capacity) during storage of 1 day, 1 week, and 4 weeks. A clear distinction could be made between the MAG crystals and TAG crystals in the blends M50-T50 and M75-T25 based on WAXS, SAXS, and phase contrast microscopy. This indicates that both gelators crystallize separately. During the follow-up study of the dynamically produced samples, a synergistic effect was found for Dy-M50-T50 and Dy-M75-T25; however, it was not maintained upon storage. The initial rigidity of 2.4 × 10 4 Pa and 2.0 × 10 4 Pa decreased to 1.5 × 10 4 Pa and 1.0 × 10 4 Pa for Dy-M50-T50 and Dy-M75-T25, respectively.