Effects of dietary glycerol monolaurate on productive performance, egg quality, serum biochemical indices, and intestinal morphology of laying hens / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Glycerol monolaurate (GML) has been widely used as an effective antibacterial emulsifier in the food industry. A total of 360 44-week-old Hy-Line brown laying hens were randomly distributed into four groups each with six replicates of 15 birds, and fed with corn-soybean-meal-based diets supplemented with 0, 0.15, 0.30, and 0.45 g/kg GML, respectively. Our results showed that 0.15, 0.30, and 0.45 g/kg GML treatments significantly decreased feed conversion ratios (FCRs) by 2.65%, 7.08%, and 3.54%, respectively, and significantly increased the laying rates and average egg weights. For egg quality, GML drastically increased albumen height and Haugh units, and enhanced yolk color. Notably, GML increased the concentrations of polyunsaturated and monounsaturated fatty acids and reduced the concentration of total saturated fatty acids in the yolk. The albumen composition was also significantly modified, with an increase of 1.02% in total protein content, and increased contents of His (4.55%) and Glu (2.02%) under the 0.30 g/kg GML treatment. Additionally, GML treatments had positive effects on the lipid metabolism of laying hens, including lowering the serum triglyceride and total cholesterol levels and reducing fat deposition in abdominal adipose tissue. Intestinal morphology was also improved by GML treatment, with increased villus length and villus height to crypt depth ratio. Our data demonstrated that GML supplementation of laying hens could have beneficial effects on both their productivity and physiological properties, which indicates the potential application of GML as a functional feed additive and gives us a new insight into this traditional food additive.

Conversão enzimática de triacilgliceróis em mono e diacilgliceróis de interesse industrial / Enzymatic conversion of triacylglycerols to mono and diacilglycerols of industrial interest

Mono e diacilgliceróis são produtos empregados na indústria alimentícia, farmacêutica, cosmética e química como emulsificantes e melhoradores de viscosidade de produtos alimentícios, cosméticos e farmacêuticos. No entanto, a forma mais usual de obtê-los é por síntese química, o que acaba rendendo produtos finais caros e com atributos de qualidade, rendimento e de aplicabilidade tecnológica inferiores aos esperados. A busca por formas de obtenção mais racionais, eficientes e com melhor padrão de qualidade destes produtos foi o objetivo principal do trabalho, por meio de hidrólise parcial enzimática, que necessita de condições de reação mais brandas. Foram avaliadas a hidrólise enzimática descontína, empregando como substrato a trioleína técnica, e a hidrólise enzimática descontínua-alimentada, usando como substrato o óleo de girassol médio oléico. Foi utilizada, em ambos processsos, a lipase imobilizada sn-1,3 específica Lipozyme RM IM (de Rhizomucor miehei). A caracterização dos padrões e dos substrados, bem como o acompanhamento da formação dos produtos da hidrólise enzimática foram feitos por determinação da porcentagem de hidrólise, cromatografia em camada delgada (TLC), dos perfis das curvas de fusão e cristalização por calorimetria diferencial de varredura (DSC), cromatografia gasosa (CG) e cromatografia de exclusão de tamanho de alto desempenho (HPSEC). Os parâmetros de hidrólise descontínua foram o tempo de reação, a temperatura e a concentração inicial de substrato. Os parâmetros de hidrólise descontínua-alimentada foram tempo de enchimento e intervalo de alimentação de substrato. Para as respostas analíticas de porcentagem de hidrólise e de composição de frações lipídicas foi aplicado um modelo de regressão múltipla com base em metodologia de superfície de resposta. Os resultados experimentais observados nas reações de hidrólise enzimática descontínua de trioleína técnica mostraram de 24,7 a 34,2% de mono e diacilgliceróis (para 5% de óleo na emulsão) e de 21,4 a 33,6% de mono e diacilgliceróis (para 20% de óleo na emulsão). Os resultados experimentais observados nas reações de hidrólise enzimática descontínua-alimentada de óleo de girassol médio oléico (para 15% de óleo na emulsão), mostraram de 7,9 a 31,8% de mono e diacilgliceróis. Os modelos de superfície de resposta foram considerados significativos e preditivos. As hidrólises obtidas no formato descontínuo e descontínuo-alimentado permitiram efetivamente a obtenção de frações de mono/ diacilgliceróis com vários graus de eficiência de conversão e com corretas identificação e quantificação das frações de lipídios procuradas. As correlações feitas entre porcentagem de hidrólise e entalpias de cristalização e fusão, corroboradas com os resultados qualitativos e/ou quantitativos diretos obtidos na cromatografia de camada delgada (TLC) e de HPSEC, demonstraram que estes atributos podem positivamente indicar a ocorrência efetiva de reação de hidrólise, além de auferir uma escala de desempenho de reação alinhada com o previsto na literatura, à medida que são aumentadas a temperatura, o tempo de hidrólise e a porcentagem inicial de substrato oleoso, sob regime descontínuo, e que puderam ser melhoradas, de forma inovadora, sob parâmetros de tempo total de alimentação e de intervalo de alimentação, sob regime descontínuo-alimentado. A hidrólise parcial enzimática de triacilgliceróis utilizando lipase imobilizada sn-1,3 específica pode ser considerada uma alternativa às vias químicas para a produção de misturas de mono e diacilgliceróis para utilização como aditivos químicos.

Mono and diacylglycerols are products used in the food, pharmaceutical, cosmetic and chemical industries as emulsifiers and viscosity improvers for food products, cosmetics and pharmaceuticals. However, the most usual forms of obtaining them are by chemical synthesis, which ends up yielding expensive final products with attributes of quality, yield and technological applicability lower than expected. The search for more rational, efficient and better quality standards of these products was the aim of the work, through partial enzymatic hydrolysis, which requires milder reaction conditions. Discontinuous enzymatic hydrolysis was evaluated using technical triolein as substrate and discontinuous-fed enzymatic hydrolysis using as the substrate the mid oleic sunflower oil. In both processes, immobilized lipase sn-1,3 specific Lipozyme RM IM (from Rhizomucor miehei) was used. The characterization of the patterns and substrates, as well as the monitoring of the formation of the products from the enzymatic hydrolysis were made by determining the percentage of hydrolysis, thin layer chromatography (TLC), profiles of the melting and crystallization curves by differential scanning calorimetry ( DSC), gas chromatography (GC) and high performance size exclusion chromatography (HPSEC). The parameters of discontinuous hydrolysis were the reaction time, the temperature and the initial substrate concentration. The parameters of discontinuous-fed hydrolysis were filling time and substrate feed interval. For the analytical responses of hydrolysis percentage and composition of lipid fractions a multiple regression model was applied based on response surface methodology. The experimental results observed in the reactions of discontinuous enzymatic hydrolysis of technical triolein indicated amounts of mono- and diacylglycerols from 24.7 to 34.2% (for 5% of oil in the emulsion) and from 21.4 to 33.6% for mono and diacylglycerols with 20% oil in the emulsion. The experimental results observed in the reactions of discontinuous-fed enzymatic hydrolysis of mid oleic sunflower oil (for 15% oil in the emulsion), showed from 7.9 to 31.8% of mono and diacylglycerols. Response surface models were considered significant and viii predictive. The hydrolysis obtained in the discontinuous and discontinuous-fed form allowed to obtain fractions of mono / diacylglycerols with various degrees of conversion efficiency and with correct identification and quantification of the lipid fractions sought. The correlations between the percentage of hydrolysis and enthalpies of crystallization and fusion, corroborated with the qualitative and / or quantitative direct results obtained in thin layer chromatography (TLC) and HPSEC, showed that these attributes can positively indicate the effective occurrence of reaction of Hydrolysis, in addition to achieving a reaction performance scale in line with the literature, as the temperature rate, the hydrolysis time and the initial percentage of oily substrate are increased under a discontinuous regime and can be improved, in a innovative form, under parameters of total filling time and feeding interval, under a fed-batch regime. The partial enzymatic hydrolysis of triacylglycerols using specific sn-1,3-specific immobilized lipase may be considered an alternative to the chemical pathways for the production of mono- and diacylglycerol blends for use as chemical additives.

Obtención de monoglicéridos de aceite de ricino empleando glicerina refinada y cruda: estudio de las principales variables del proceso / Production of monoglycerides from castor oil using crude and refined glycerin: study of the main variables of the process

Los monoglicéridos son ampliamente usados como emulsionantes en las industrias alimentaria, farmacéutica y cosmética. En este estudio se reportó la producción de monoglicéridos de aceite de ricino por reacciones de glicerólisis usando glicerina USP y la glicerina cruda, subproducto del proceso de producción del biodiesel de palma. Se emplearon catalizadores básicos como hidróxidos metálicos y óxido de plomo, y ácidos como acetato de plomo. Los resultados señalan que los catalizadores basados en plomo proporcionaron mayores conversiones hacia los monoglicéridos que los basados en sodio, potasio y calcio. Se encontró que una alta relación molar de aceite/glicerina fue una variable determinante que favorece altas concentraciones de monoglicéridos. Finalmente, se demostró que el uso de glicerina cruda para la producción de monoglicéridos es factible, aunque en este caso la concentración de monoglicéridos obtenidos se disminuye aproximadamente en un 20% debido, probablemente, al envenenamiento de los catalizadores.

Monoglycerides are widely used as emulsifiers in food, pharmaceutical and cosmetic industries. In this article was reported the production of monoglycerides from castor oil, by glicerolysis reactions, using USP glycerine and crude glycerol derived from a palm-biodiesel production process. Metalic hydroxides and lead oxide were used as basic catalysts, while lead acetate was used as acid catalyst. Results showed that the lead-based catalysts exhibited higher conversions to monoglycerides respect to those based on sodium, potassium and calcium. We found that a high molar ratio oil/glycerol was a determinant variable that favors high concentrations of monoglycerides. Ultimatelly, it was shown that it is feasible to use crude glycerol for the production of monoglycerides, although in this case the concentration of monoglycerides is reduced 20% due to the poisoning of the catalysts.

A study on the lipids of Ascaris suum ova

The present study was undertaken to observe the quality and quantity of lipid constituents by the developing Ascaris suum eggs. The collected eggs from the uterus of A. suum were classified into 3 groups, i.e., single cell stage, morula stage and embryonated eggs, and were subjected to analyse their lipid fractions. To obtain the morula stage eggs, 10 to 11 incubation days at 30 degree C were needed and for the embryonated eggs, 30 to 31 days were lasted. At the time of experiment, their indices of development by Hoffman were 285(morula stage) and 42 (embryonated stage) respectively. Lipid extraction was done by the methods of Folch et a1. (1957) and Kenny (1952), and then the extracted lipid fractions from the above 3 groups of eggs were separated by thin layer chromatography. Those fractions were also subjected to perform the quantitative analyses of fatty acids, glycerides, cholesterol and phospholipids. The results obtained were summarized as follows. Total amount of fatty acid was decreased from 12.9 mg per gram of eggs (single cell stage) to 6.6 mg/gm (embryonated eggs), whereas the proportion of free fatty acid to total fatty acid was constantly increased from 77.5 percent to 89.4 percent during the period of egg development. Total amount of glycerides was also increased from 33.0 mg/gm of single cell stage to 55.9 mg/gm of the embryonated eggs. The most abundant glyceride among 3 glycerides discovered from A. suum eggs was triglyceride, and the least was monoglyceride. The amount of free cholesterol was much larger than that of ester form in general, and it reached maximum in the eggs of morula stage (4.6 mg/gm). The increase of total cholesterol was monitored during the development of A. suum eggs from 3.3 mg/gm to 5.4 mg/gm. The following 8 phospholipids were detected in the embryonated eggs, i.e., lysophosphatidyl choline, phosphatidyl inositol, sphingomyelin, phosphatidyl choline, phosphatidyl glycerol, phosphatidyl serine, phosphatidyl ethanolamine and unknown phospholipid. But in the single cell stage eggs, 4 kinds out of the above 8 phopholipids were not observed, and in the morula stage eggs, 2 kinds were absent among the 8 phospholipids.