Development and characterization of structured lipids containing capric and conjugated linoleic acids as functional dietary lipid molecules

Structured DAG oil ameliorates renal injury in streptozotocin-induced diabetic rats through inhibition of NF-κB and activation of Nrf2 pathway

Accumulating evidence suggested that inflammatory processes are involved in the development of diabetic nephropathy (DN). Here, we have tested the hypothesis that Caprylic Acid (Cy)-diacylglycerol (DAG) oil (Cy-DAG), a novel structurally formulated lipid with high nutritional value, ameliorated DN in streptozotocin (STZ)-induced diabetic rats through the anti-inflammatory mechanisms. Basic hematological, biochemical parameters, immunoblotting, immunofluorescence and flow cytometry analysis were performed to observe the anti-inflammatory potential of Cy-DAG oil. The data revealed that STZ significantly increased the renal oxidative stress markers and decreased the levels of renal enzymatic and non-enzymatic antioxidants. Moreover, renal nitric oxide (NO), tissue necrosis factor-α (TNF-α), interleukin-6 (IL-6) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) were also increased in the renal tissue of STZ-treated rats. Further, DAG oil pretreatment produced a significant improvement in renal antioxidant status, reduced the lipid peroxidation and the levels of inflammatory markers in STZ-treated kidney. Similarly, results of protein expression showed that DAG oil pretreatment normalized the renal expression of Nrf2/Keap1 and its downstream regulatory proteins in STZ-treated condition. Immunohistochemical observations provided further evidence that DAG oil effectively protected the kidney from STZ-mediated oxidative damage. These results suggested that the DAG oil ameliorated STZ-induced oxidative renal injury by the activation of AKT/Nrf2/HO-1 pathway and the inhibition of ROS/MAPK/NF-κB pathway.

Solvent-Free Lipase-Catalyzed Synthesis of Diacylgycerols as Low-Calorie Food Ingredients

Problems derived from obesity and overweight have recently promoted the development of fat substitutes and other low-calorie foods. On the one hand, fats with short- and medium-chain fatty acids are a source of quick energy, easily hydrolyzable and hardly stored as fat. Furthermore, 1,3-diacylglycerols are not hydrolyzed to 2-monoacylglycerols in the gastrointestinal tract, reducing the formation of chylomicron and lowers the serum level of triacylglycerols by decreasing its resynthesis in the enterocyte. In this work, these two effects were combined to synthesize short- and medium-chain 1,3-diacylglycerols, leading to a product with great potential as for their low-calorie properties. Lipase-catalyzed transesterification reactions were performed between short- and medium-chain fatty acid ethyl esters and glycerol. Different variables were investigated, such as the type of biocatalyst, the molar ratio FAEE:glycerol, the adsorption of glycerol on silica gel, or the addition of lecithin. Best reaction conditions were evaluated considering the percentage of 1,3-DAG produced and the reaction rate. Except Novozym 435 (Candida antarctica), other lipases required the adsorption of glycerol on silica gel to form acylglycerols. Lipases that gave the best results with adsorption were Novozym 435 and Lipozyme RM IM (Rhizomucor miehei) with 52 and 60.7% DAG at 32 h, respectively. Because of its specificity for sn-1 and sn-3 positions, lipases leading to a higher proportion of 1,3-DAG vs. 1,2-DAG were Lipozyme RM IM (39.8 and 20.9%, respectively) and Lipase PLG (Alcaligenes sp.) (35.9 and 19.3%, respectively). By adding 1% (w/w) of lecithin to the reaction with Novozym 435 and raw glycerol, the reaction rate was considerably increased from 41.7 to 52.8% DAG at 24 h.

Production of trans-free margarine stock by enzymatic interesterification of rice bran oil, palm stearin and coconut oil

BACKGROUND

Trans-free interesterified fat was produced for possible usage as a spreadable margarine stock. Rice bran oil, palm stearin and coconut oil were used as substrates for lipase-catalyzed reaction.

RESULTS

After interesterification, 137-150 g kg(-1) medium-chain fatty acid was incorporated into the triacylglycerol (TAG) of the interesterified fats. Solid fat contents at 25 degrees C were 15.5-34.2%, and slip melting point ranged from 27.5 to 34.3 degrees C. POP and PPP (beta-tending TAG) in palm stearin decreased after interesterification. X-ray diffraction analysis demonstrated that the interesterified fats contained mostly beta' polymorphic forms, which is a desirable property for margarines.

CONCLUSIONS

The interesterified fats showed desirable physical properties and suitable crystal form (beta' polymorph) for possible use as a spreadable margarine stock. Therefore, our result suggested that the interesterified fat without trans fatty acid could be used as an alternative to partially hydrogenated fat.

Characterization of a rice bran oil structured lipid

Rice bran oil (RBO) was enzymatically modified in a continuous packed bed bioreactor to incorporate caprylic acid with Lipozyme RM IM as biocatalyst. The reaction product was purified by short-path distillation. Rice bran oil structured lipid (RBOSL) contained 32.1 mol % caprylic acid. Positional analysis revealed 0.7 mol % caprylic acid at the sn-2 position and 47.8 mol % caprylic acid at the sn-1,3 positions. Composition of free fatty acids and smoke point of RBO and RBOSL were not significantly different. Saponification value, iodine value, and viscosity of RBO were significantly different from those of RBOSL. The color of RBOSL was darker, more yellow and less green than RBO. Volatile compounds in RBO and RBOSL were determined by GC-MS. Melting onset temperatures of RBO and RBOSL were not significantly different, while melting end point temperatures and melting enthalpies were significantly different. This characterization study results will help determine potential food applications of RBOSL.