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Introduction
Published in Yip-Wah Chung, Monica Kapoor, Introduction to Materials Science and Engineering, 2022
When these molecules condense to form the respective solids, argue why the solid formed by straight molecules has higher melting point than one formed by angled molecules.Hint: Think about which molecule can give rise to tighter packing.Compare oleic acid and elaidic acid. They have the same chemical formula (C18H34O2) but different shapes. Use the result from (a) to explain their different melting points.
Flavor Development during Roasting
Published in Hii Ching Lik, Borém Flávio Meira, Drying and Roasting of Cocoa and Coffee, 2019
The oils present in coffee have the capacity to cover the tongue during ingestion, thus providing the oily and creamy mouthfeel that is characteristic of the beverage (Figueiredo et al., 2015). Triacylglycerols account for approximately 75% (w/w) of total coffee lipids in freshly brewed coffee, whereas free fatty acids account for only approximately 1% (Trugo, 2003). The content of saturated fatty acids, including arachidic, stearic and palmitic acid were reported to be potential discriminators of the quality of specialty coffees, indicating better sensory quality. Stearic and arachidic acid were found to contribute to coffee body and increase in flavor, being correlated with fragrance and aromatic compounds beneficial to quality. Conversely, the content of unsaturated fatty acids (elaidic, oleic, linoleic and linolenic acids) were r eported to be negatively correlated with sensory quality, especially elaidic acid, a trans-isomer of oleic acid. This may be attributed to the propensity of unsaturated fatty acids to oxidize leading to the development of rancidity and in many cases to the formation of undesirable aromas in oils. The content of unsaturated fatty acids have also been associated with less intense acidity, fragrance, flavor and body, which are highly valued in specialty coffees (Figueiredo et al., 2015).
Clay Mineral Catalysis of Isomerization, Dimerization, Oligomerization, and Polymerization Reactions
Published in Benny K.G. Theng, Clay Mineral Catalysis of Organic Reactions, 2018
The dimerization (and oligomerization) of unsaturated fatty acids has received much attention because the products have applications in the adhesive, paint, and plastic industries. The reaction is commonly carried out in an autoclave at a high temperature and under pressure (Adams 1987). Figure 6.3 shows a simplified diagram for the dimerization of oleic acid (C18H34O2) together with the principal side products. As Koster et al. (1998) have pointed out, each product comprises a variety of compounds due to the occurrence of many side reactions, notably hydrogen transfer, double-bond shift, cis-trans isomerization, and chain branching. Since the oleic acid feedstock commonly contains other fatty acids, such as elaidic acid (the trans isomer of oleic acid), palmitic acid, and stearic acid, the results of various dimerization reactions are not always self-consistent.
Exploring the influence of particle phase in the ozonolysis of oleic and elaidic acid
Published in Aerosol Science and Technology, 2023
Ravleen Kaur Kohli, Ryan S. Reynolds, Kevin R. Wilson, James F. Davies
A comparison between the ozonolysis of oleic acid (OA) and elaidic acid (EA) is presented to explore differences in their reactivity and phase behavior that arise from the different orientation of the carbon–carbon double bond. In bulk at room temperature, OA is a liquid while EA is a solid. Both species are soluble in organic solvents, such as ethanol and 1-proponal, which evaporates after levitation resulting in the formation of either liquid or solid particles. In general, levitated particles containing OA were observed to exist in liquid state, whereas EA attained both supercooled liquid and solid phase states on a pseudo-random basis. Ozonolysis measurements were performed to explore the influence of these phase states on reactivity and reaction mechanisms. Additional measurements using a temperature-controlled flow-tube were performed as a means of comparing phase states using temperature as a control.
Production of trans-free interesterified fat using indigenously immobilized lipase
Published in Preparative Biochemistry & Biotechnology, 2019
Monali R. Kavadia, Manish G. Yadav, Rajeshkumar N. Vadgama, Annamma A. Odaneth, Arvind M. Lali
Trans fatty acid analysis of the final interesterified sample was conducted by high-performance liquid chromatography (HPLC) in an Agilent 1200 Chromatography System (CA, USA) equipped with a quaternary solvent delivery module, and an Agilent evaporative light scattering detector (ELSD) operated at 60 °C with a nitrogen pressure of 3.5 bar. Interesterified sample was subjected to methylation using BF3-methanol to produce fatty acid methyl esters (FAMEs) using the method described by Whitney et al.[19] FAMEs were then subjected to HPLC separation and retention times of FAMEs were compared to standard elaidic acid methyl ester (C18 trans fatty acid methyl ester) to determine the presence of any trans fatty acid content in the interesterified product.