Luis Vázquez

Stepwise esterification of phytosterols with conjugated linoleic acid catalyzed by Candida rugosa lipase in solvent-free medium.

We conducted a near quantitative esterification of phytosterols from soybean oil deodorizer distillate with conjugated linoleic acid. We used a 1:1 molar ratio of sterols to conjugated linoleic acid. For that matter, stepwise addition of sterols was investigated. Total sterols were divided into several portions and added sequentially to the reaction mixture. Using this methodology, purities of up to 80% steryl esters were obtained that consumed more than 90% of the total conjugated linoleic acid. In addition, the effects of temperature, amount, and stability of lipase were also evaluated.

Comparative in vitro intestinal digestion of 1,3-diglyceride and 1-monoglyceride rich oils and their mixtures

Intestinal in vitro digestion of 1,3-diolein (DO), 1-monoolein (MO), DO:MO (1:1) rich oils, and triolein (TO), was performed to study the rate and extent of hydrolysis as well as their bioaccessibility in detail, with special emphasis on 1,3-DO and 1-MO forms, as potential bioactive lipids with additional technological functions such as self-emulsifying lipids. The importance of in vitro conditions on non-desirable acylmigration was also shown. The rate of in vitro intestinal lipolysis was in increasing order TO<DO<DO:MO<MO. At the end of digestion, DO:MO was hydrolyzed to absorbable products at the same level than the MO sample. The degree of lipolysis positively correlated with the level of 1-MG and negatively with the level of 2-MG. Either DO, MO or DO:MO produced higher level of 1-MG than TO. DO:MO produced the highest level of 1-MG and a high ratio of 1-MG to 2-MG. Most hydrolysis products (>95%) of DO, MO and DO:MO were found within the micellar phase fraction during digestion, suggesting a high bioaccessibility. A positive correlation between the degree of lipolysis and the number of mixed micelles formed at the end of digestion was found. As summary, the obtained results would enhance the selection of glycerides to formulate ingredients with different purposes. Thus, in case a final high level of 1-MO would be desired to take advantage of the bioactivity of 1-MO, oils under the form of DO or DO:MO might be superior to MO. In case a high 1-MO level together with a low 2-MO level would be desired at the same time, mixtures of DO:MO or MO would be preferred. In case a higher self-emulsifying ability would be desired, the preferred forms would be MO and DO:MO. Finally, in case all the potential functionalities would be desired at the same time, namely the highest bioactivity, together with a high self-emulsifying ability, the mixture DO:MO might be suggested as an interesting product, with the additional economical advantage.

Discrimination against diacylglycerol ethers in lipase-catalysed ethanolysis of shark liver oil

Lipase-catalysed ethanolysis of squalene-free shark liver oil was investigated. The mentioned shark liver oil was comprised mainly of diacylglycerol ether and triacylglycerols. In order to test discrimination against diacylglycerol ether, up to 10 different lipases were compared. The ratio of oil to ethanol and lipase stability were also evaluated. Surprisingly, lipase from Pseudomonas stutzeri was the fastest biocatalyst among all assayed, although poor discrimination against diacylglycerol ether was observed. The best results in terms of selectivity and stability were obtained with immobilised lipase from Candida antarctica (Novozym 435). Ethanolysis reaction after 24h in the presence of Novozym 435 produced total disappearance of triacylglycerol and a final reaction mixture comprised mainly of diacylglycerol ethers (10.6%), monoacylglycerol ethers (32.9%) and fatty acid ethyl esters (46.0%). In addition, when an excess of ethanol was used, diacylglycerol ethers completely disappeared after 15 h, giving a final product mainly composed of monoacylglycerol ethers (36.6%) and fatty acid ethyl esters (46.4%).

Antiproliferative effect of alkylglycerols as vehicles of butyric acid on colon cancer cells.

The anticarcinogenic activity of synthetic 1-O-octadecyl-2,3-dibutyroilglycerol (D-SCAKG) in tumor-cell line of colonocytes (SW620) was performed. The effect of the previously digested D-SCAKG under in vitro intestinal conditions was compared to the bioactivity of non-digested D-SCAKG. Antiproliferative activity of each individual product from digestion (1-O-octadecyl-2-butyroilglycerol; 1-O-octadecyl glycerol; butyric acid) was also performed. The impact of solubilization of lipid products within micellar structures was also tested. The 1-O-octadecyl glycerol was the most active compound, followed by 1-O-octadecyl-2-butyroilglycerol, D-SCAKG and butyric acid. The 1-O-octadecyl glycerol and butyric acid were the only molecules that showed antiproliferative effect in absence of micelles. Digested D-SCAKG was 4-fold more effective than non-digested D-SCAKG. A synergism between 1-O-octadecyl-2-butyroilglycerol and 1-O-octadecyl glycerol was evidenced. As summary, the synthetic D-SCAKG seems to be an interesting antitumoral lipid against colonocytes, especially after previous intestinal digestion, and mainly due to the synergism of the major products, namely 1-O-octadecyl-2-butyroilglycerol and 1-O-octadecyl glycerol. At the same time, 1-O-octadecyl-2-butyroilglycerol would constitute a stable esterified form of butyric acid for its vehiculization.