Synthesis, structure, and thermal properties of 1,2-dipalmitoylgalloylglycerol (DPGG), a novel self-adhering lipid

Combining antioxidants and processing techniques to improve oxidative stability of a Schizochytrium algal oil ingredient with application in yogurt

Oxidative instability limits incorporation of ω-3 fatty acids (FAs) into some products. This research combined processing techniques with antioxidant addition to overcome these barriers. Oleogels, microencapsulates, and microencapsulated gel ingredients were prepared using Schizochytrium spp. algal oil (AO) in combination with α, β, γ, and δ tocopherols or 1-o-galloylglycerol (GG) as antioxidants. Ingredients were tested for physicochemical stability and optimal ingredients were selected to prepare yogurts as a model food with ideal matrix. Yogurts were analyzed for physicochemical properties. After 24-days storage at 4 °C, yogurt containing microencapsulated oleogel with GG as antioxidant exhibited average peroxide and p-Anisidine values of 7.17 mmol O2/kg of oil and 118.85 abs/g, respectively. These values were similar to store-bought yogurt using saturated fat source, with values of 6.83 mmol O2/kg of oil and 117.95 absorbance/g, respectively. These results could lead to incorporation of ω-3 FAs into foods, cosmetics, and pharmaceuticals in the future.

Lipase-catalyzed one-step regioselective synthesis of 1,2-dioctanoylgalloylglycerol in a solvent-free system: Optimization of reaction conditions and structural elucidation

A multi-functional galloylated structured lipid, 1,2-dioctanoylgalloylglycerol (DOGG), was synthesized enzymatically via a regioselective transesterification of propyl gallate and trioctanoate using an immobilized food-grade Candida antarctica lipase B (Lipozyme® 435) as the biocatalyst under solvent-free condition. The variables that affect the reaction, including reaction temperature, substrate ratio, reaction time, and enzyme load, were evaluated and optimized using Taguchi method and response surface methodology. Both methods predicted the same optimal reaction condition, resulting in a 68.8 ± 1.3% DOGG yield with reaction selectivity of 82.9 ± 0.6% at 90 °C, 25/1 trioctanoate/PG (mol/mol), 72 h reaction, and 25% enzyme load relative to the total substrate weight. The structure of the reaction product was elucidated using NMR spectroscopy and ESI-HRMS, confirming the regioselectivity of the reaction. Enzyme retained 50% of its activity after 5 cycles of reuse. It is feasible to synthesize DOGG as a potential antioxidant and nutraceutical using Lipozyme® 435.

Solvent-free enzymatic synthesis of 1,2-dipalmitoylgalloylglycerol: Characterization and optimization of reaction condition

A novel diacylglycerol-based galloyl structured lipid, 1,2-dipalmitoylgalloylglycerol (DPGG), was synthesized using the enzymatic transesterification of propyl gallate (PG) and tripalmitin under solvent-free condition. An immobilized and commercially available food-grade Candida antarctica lipase B, Lipozyme® 435, was used as the biocatalyst. The reaction variables that affect the yield of DPGG were optimized using a 3³ full factorial design. At 70 °C, DPGG was obtained at a yield of 33.0 ± 2.0% with PG conversion at 44.8 ± 1.8% when the following condition was used: 25 substrate molar ratio of tripalmitin to PG, 120 h reaction time, and 25% enzyme load relative to the total substrate weight. The structure of reaction product was elucidated using Fourier-transform infrared spectroscopy (FT-IR), electrospray ionization high-resolution accurate-mass tandem mass spectrometry (ESI-HRAM-MS/MS), and 1D and 2D nuclear magnetic resonance spectroscopy (NMR). The effects of different lipases and galloyl donors/acceptors on the transesterification were also investigated.

Janus-compartmental alginate microbeads having polydiacetylene liposomes and magnetic nanoparticles for visual lead(II) detection

Janus-compartmental alginate microbeads having two divided phases of sensory polydiacetylene (PDA) liposomes and magnetic nanoparticles were fabricated for facile sensory applications. The sensory liposomes are composed of PDA for label-free signal generation and 1,2-dipalmitoyl-sn-glycero-3-galloyl (DPGG) lipids whose galloyl headgroup has specific interactions with lead(II). The second phase having magnetic nanoparticles is designed for convenient handling of the microbeads, such as washing, solvent exchange, stirring, and detection, by applying magnetic field. Selective and convenient colorimetric detection of lead(II) and efficient removal of lead(II) by alginate matrix at the same time are demonstrated.

Synthesis and characterization of a series of novel phenol- and polyphenol-based glycerolipids

A building block approach was used to design a modular synthetic route for the preparation of novel glycerolipids with phenolic and polyphenolic headgroups. Based on this scheme, it is possible to vary the substitution pattern of the headgroup, the stereochemistry of the backbone, and the length of the sidechains. Five glycerolipids with different headgroups and identical backbone stereochemistry and chain length have been prepared.Key words: glycerolipid, polyphenol, hydrogen bonding, lipid-protein interaction, self-adhering.

Monolayer behavior of 1,2-dipalmitoylgalloylglycerol, a synthetic lipid with strong cohesive properties

Monolayers of 1,2-dipalmitoylgalloylglycerol (DPGG) were investigated at the air-water interface. The monolayers exhibit high rigidity which leads to the formation of surface tension gradients in the film. Transfer to solid substrate yields homogeneous Langmuir-Blodgett films with low surface roughness. Large numbers of aggregates were observed by Brewster angle microscopy and imaging ellipsometry at relatively high molecular areas. At all pressures, the DPGG molecules adopt conformations corresponding to low tilt angles. Constant area measurements result in a pressure increase as the film rearranges to maximize the intermolecular interactions. An optimal intermolecular distance required for the formation of a hydrogen-bond network between headgroups is proposed to explain the observed, highly cohesive monolayer behavior.