Production of thermostable lipase by Thermomyces lanuginosus on solid-state fermentation: selective hydrolysis of sardine oil.

A naturally immobilized biocatalyst with lipase activity was produced by Thermomyces lanuginosus on solid-state fermentation with perlite as inert support. Maxima lipase activities (22 and 120 U/g of dry matter, using p-nitrophenyl octanoate and trioctanoine, respectively, as substrates) were obtained after 72 h of solid culture, remaining nearly constant up to 120 h. Maxima lipase activity was found at 60 to 85 °C and pH 10. The biocatalyst was stable at 60 °C for at least 4 h of incubation and a pH from 7 to 10. Energy values of activation and deactivation of lipase were of 26 and 6.7 kJ/mol, respectively. The biocatalyst shows high selectivity for the release of the omega-3 polyunsaturated fatty acids, eicosapentaenoic (EPA) and docosahexaenoic acids (DHA), during the hydrolysis of sardine oil. The EPA/DHA ratio (16:6) released by this biocatalyst was superior to that obtained with the commercial preparations of T. lanuginosus.

Fitoesteroles y escualeno como hipocolesterolémicos en cinco variedades de semillas de Cucurbita maxima y Cucurbita moschata (calabaza) / Phytosterols and squalene as hypocholesterolemic substances in five varieties of Cucurbita maxima and Cucurbita moschata (pumpkin) seeds

Introducción: la semilla de calabaza se ha estudiado y utilizado en el tratamiento de enfermedades parasitarias, hipertrofia benigna prostática, cistitis y como hipoglicemiante.Sin embargo, se desconocen investigaciones que refieran el uso de la semilla de calabaza y sobre todo de los fitoesteroles y escualeno como elementos hipocolesterolémicos en humanos. Objetivo: determinar el contenido de fitoesteroles y escualeno de cinco variedades de semilla de calabaza para su posible uso como hipocolesterolémicos en humanos. Métodos: se estudiaron semillas de calabaza de dos especies, Cucurbita maxima y Cucurbita moschata, de Cuba y México de las variedades Fifí, Marucha, INIVIT C- 88 (cubanas), Chata y Tapatía (mexicanas), se determinó el perfil de fitoesteroles (beta-sitosterol, campesterol, estigmasterol y estigmastenol) y escualeno mediante cromatografía gas-líquido. Resultados: el contenido de extracto etéreo y grasa verdadera en las semillas osciló entre 331,5 y 346; 307 y 336 g/kg, respectivamente. La variedad fifí (Cucurbita moschata) presentó el mayor contenido de material insaponificable (35,0 g/kg), mostró diferencias significativas (p< 0,001) con las demás variedades y superior a las semillas oleaginosas convencionales. La concentración de escualeno y beta-sitosterol resultó superior en la variedad marucha (Cucurbita moschata) (40,27 y 202,59mg/100 g), que indicó diferencias significativas (p< 0,001) con las restantes variedades. Las variedades chata y marucha presentaron el mayor contenido de campesterol (50,08y 49,31 mg/100 g, respectivamente), así como la marucha encontró la mayor concentración de stigmasterol y estigmastenol (1,75y 28,63 mg/100 g), además, los contenidos resultaron superiores a los alimentos vegetales frecuentes en las dietas. Conclusiones: los resultados obtenidos en la concentración de los fitoesteroles y escualeno en las variedades analizadas, sugieren el estudio de la semilla de calabaza como posible hipocolesterolémico en humanos

Introduction: the pumpkin seed has been studied and used in the treatment of parasitic diseases, benign prostatic hypertrophy, cystitis and as hypoglycemic substance. However, the research concerning the use of pumpkin seeds and especially the sterols and squalene as hypocholesterolemic elements in humans is unknown. Objective: to determine the phytosterol and squalene content of five varieties of pumpkin seeds for their potential use as hypocholesterolemic compounds in humans. Methods: the pumpkin seeds from two species called Cucurbita maxima and Cucurbita moschata from Cuba and Mexico were studied. The varieties were Fifi, Marucha, INIVIT C-88 (Cuban), Tapatía and Chata (Mexican) for which the profile of phytosterols (beta-sitosterol, campesterol, stigmasterol and stigmastenol) and the squalene were determined using gas-liquid chromatography. Results: the content of ethereal extract and real fat in the seeds ranged 331.5 to 346, and 307 to 336 g/kg, respectively. The variety Fifi (C. moschata) had the highest content of unsaponifiable material (35.0 g/kg) and showed significant differences (p< 0.001) compared with other varieties and above that of conventional oilseeds. The squalene, and beta-sitosterol concentration was higher Marucha (Cucurbita moschata) (40.27 and 202.59 mg/100 g), indicating significant differences (p< 0.001) compared with other varieties. Marucha and Chata varieties exhibited the highest campesterol content (50.08 and 49.31 mg/100 g, respectively), and the Marucha evidenced the largest concentration of stigmasterol and stigmastenol (1.75 and 28.63 mg/100 g); additionally, the amounts contained were above those of the common vegetable food in the diet. Conclusions: the results in phytosterol and squalene concentrations achieved in the studied varieties suggested that the pumpkin seeds be studied as a possible hypocholesterolemic substance for humans

Effect of pH, aeration and feeding non-sterilized agave juice in a continuous agave juice fermentation.

BACKGROUND: Continuous cultures have been used since the 1950s in beer and wine fermentations due to their higher productivities compared to traditional batch systems; nevertheless, the tequila industry has not taken advantage of the possible improvements that continuous fermentations could offer. In this work, the effect of pH, aeration and feeding of non-sterilized medium, on the fermentative capability of two Saccharomyces cerevisiae strains (S1 and S2) cultured in continuous fermentation, using agave juice as the fermentation medium, were studied. RESULTS: In continuous cultures, the control of the medium pH (set point at 4) did not have a significant effect on fermentation efficiency compared to fermentations in which the pH was not controlled (pH 2.5 +/- 0.3). Conversely, aeration of the cultures of both strains improved biomass production and consumption of reducing sugars and ammonium. The aeration also significantly augmented ethanol production only for S1 cultures (P < 0.05). Furthermore, the feeding of medium, either sterilized or not, did not show significant differences on the production of ethanol for S1 cultures. Higher concentrations of acetoin, succinic acid and diacetyl were found in the cultures fed with non-sterilized medium. CONCLUSIONS: Compared to S2, S1 has a better fermentative performance in continuous non-sterilized medium fermentations. Not controlling the pH during the cultures could prevent the possibility of microbial contamination as a result of the extreme medium acidity (pH 2.5 +/- 0.3). This work showed the possibility of scaling up agave juice continuous fermentation feeding non-sterilized medium with no control of pH.