Добірка наукової літератури з теми "Enzymatic lipolysis"

Digitonin-permeabilized adipocytes were used to study the coupling of adenylate cyclase (AC) to lipolysis in exercise-trained rats. Isoproterenol-(IPR) stimulated lipolysis in permeabilized cells was significantly greater in trained than in control rats. Under essentially identical conditions, the dose-response curve for IPR stimulation of AC activity in the absence of 3-isobutyl-1-methylxanthine was similar in trained and control rats. However, the potency of stimulation by IPR as a percentage of the basal level was greater in trained rats. AC activity and lipolysis in the presence of 3-isobutyl-1-methylxanthine were also significantly greater in trained than in control rats. Least-squares analysis by plotting the log AC vs. lipolysis values showed that the regression coefficient was about three-fold greater in trained than in control rats. The concentration of endogenous adenosine 3′,5′-cyclic monophosphate (cAMP) needed to produce a half-maximal lipolytic response was 18.58 and 10.81 pmol.min-1.10(6) cells-1 in control and trained rats, respectively. Thus a positive relationship existed between lipolysis and AC activity, with a tighter coupling in trained rats. Lipolysis in response to exogenous cAMP tended to be greater in trained than in control rats, and the difference was statistically significant for 50 microM and 10 mM cAMP. Our finding support the concept that the major mechanism of enhanced lipolysis in trained rats was an increase in the activity of enzymatic step(s) distal to cAMP.

Fatty acids are intermediate substances in synthesis of oleochemical products. Enzymatic technology of fatty acids production (also known as lipolysis) is now developing as potential substitution for the conventional production of fatty acid, i.e. thermal hydrolysis of triglyceride. It offers more economical process condition, low energy consumption, and minimal product degradation compared to the conventional process. This research aims to evaluate performance of various organic solvents as reaction media in lipolysis with plant latex lipase. Organic solvents observed were chloroform, n-hexane, diethyl ether, benzene, acetone, ethanol, methanol, n-heptane, and isooctane. Analysis of each organic solvent effect on lipolysis was described based on solvents properties. Conversion of lipolysis with organic solvents is 0,10-1,25 times fold compared to conversion of non-solvent lipolysis. We suggest that dielectric constant and viscosity are the two main organic solvent properties affecting lipase performance in lipolysis. Overall, n-hexane, n-heptane, and isooctane are recommended to be used as reaction media in lipolysis with plant lipase because their effects to degree of lipolysis are positive. Keywords: lipolysis; lipase; organic solvent; frangipani

Fatty acids (FAs) are stored safely in the form of triacylglycerol (TAG) in lipid droplet (LD) organelles by professional storage cells called adipocytes. These lipids are mobilized during adipocyte lipolysis, the fundamental process of hydrolyzing TAG to FAs for internal or systemic energy use. Our understanding of adipocyte lipolysis has greatly increased over the past 50 years from a basic enzymatic process to a dynamic regulatory one, involving the assembly and disassembly of protein complexes on the surface of LDs. These dynamic interactions are regulated by hormonal signals such as catecholamines and insulin which have opposing effects on lipolysis. Upon stimulation, patatin-like phospholipase domain containing 2 (PNPLA2)/adipocyte triglyceride lipase (ATGL), the rate limiting enzyme for TAG hydrolysis, is activated by the interaction with its co-activator, alpha/beta hydrolase domain-containing protein 5 (ABHD5), which is normally bound to perilipin 1 (PLIN1). Recently identified negative regulators of lipolysis include G0/G1 switch gene 2 (G0S2) and PNPLA3 which interact with PNPLA2 and ABHD5, respectively. This review focuses on the dynamic protein–protein interactions involved in lipolysis and discusses some of the emerging concepts in the control of lipolysis that include allosteric regulation and protein turnover. Furthermore, recent research demonstrates that many of the proteins involved in adipocyte lipolysis are multifunctional enzymes and that lipolysis can mediate homeostatic metabolic signals at both the cellular and whole-body level to promote inter-organ communication. Finally, adipocyte lipolysis is involved in various diseases such as cancer, type 2 diabetes and fatty liver disease, and targeting adipocyte lipolysis is of therapeutic interest.

Microbial and enzymatic processing is an attractive area for production of valuable byproducts from fish waste. Functional screening methodologies for the purpose are still based on activities in non-specific substrates, and concept of substrate specificity is not yet validated. Therefore, reliability of using non-specific substrate for the purpose was checked. Results revealed the existence of a limited number of mutually inclusive positive isolates in non-specific and specific substrate based assays (13% for fish proteolysis and 22% for fish lipolysis), with no significant positive correlations (P>0.05). Further, using non-specific substrates in screening assays missed 57.1% and 53.33% of fish proteolytic and fish lipolytic microbes respectively, signifying the use of same substrates. Beyond methodological perspectives, the paper forms the first report on fish proteolytic activity of Bacillus tropicus, Bacillus vallismortis, Paenibacillus alvei, Staphylococcus epidermidis and Staphylococcus hominis. Similarly, fish oil hydrolyzing capacities of B. tropicus, Cronobacter sakazakii, P. alvei, Paenibacillus pinisoli, Pantoea stewartii, S. hominis and Staphylococcus caprae are recorded for the first time. Further, the paper points out 6 and 3 potential microbial species producing > 1 protease units/ml and >1 enzymatic index for fish proteolytic and lipolytic activities, without any optimization, warranting future use in fish waste management.

Adipose phospholipase A2 (AdPLA or Group XVI PLA2) plays an important role in the onset of obesity by suppressing adipose tissue lipolysis. As a consequence, AdPLA-deficient mice are resistant to obesity induced by a high fat diet or leptin deficiency. It has been proposed that AdPLA mediates its antilipolytic effects by catalyzing the release of arachidonic acid. Based on sequence homology, AdPLA is part of a small family of acyltransferases and phospholipases related to lecithin:retinol acyltransferase (LRAT). To better understand the enzymatic mechanism of AdPLA and LRAT-related proteins, we solved the crystal structure of AdPLA. Our model indicates that AdPLA bears structural similarity to proteins from the NlpC/P60 family of cysteine proteases, having its secondary structure elements configured in a circular permutation of the classic papain fold. Using both structural and biochemical evidence, we demonstrate that the enzymatic activity of AdPLA is mediated by a distinctive Cys-His-His catalytic triad and that the C-terminal transmembrane domain of AdPLA is required for the interfacial catalysis. Analysis of the enzymatic activity of AdPLA toward synthetic and natural substrates indicates that AdPLA displays PLA1 in addition to PLA2 activity. Thus, our results provide insight into the enzymatic mechanism and biochemical properties of AdPLA and LRAT-related proteins and lead us to propose an alternate mechanism for AdPLA in promoting adipose tissue lipolysis that is not contingent on the release of arachidonic acid and that is compatible with its combined PLA1/A2 activity.

The aim of this study was to investigate lipolysis and lipid oxidation of stored eggs at different temperatures (4 and 22°C) by evaluating the changes in physicochemical index, lipid profiles, enzymatic activity, and oxidative index. The results showed that the changes in physicochemical index were more significant at 22°C than at 4°C. Weight loss, moisture content, and pH of egg yolk increased significantly (P < 0.05), whereas the yolk index decreased during storage. However, there was no significant difference in lipid profiles between 4 and 22°C storage temperature. The lipid composition analysis demonstrated that lipid hydrolysis took place during egg storage and resulted in a marked decrease of PL and increase of FFA. It was also found that the content of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylinositol (PI) decreased significantly during storage. The correlation analysis showed that the lipid degradation is significantly positively related to lipase activity (P < 0.05), and the marked changes of lipid fractions are results of both hydrolysis and oxidation. It can be concluded that the egg physicochemical index and lipase activity were greatly influenced by temperature during storage, but the yolk lipid stability was not significantly influenced by storage temperature.

Abstract We describe a method for routine immunoturbidimetry of apolipoproteins (apo) A-I, A-II, and B in both normo- and hyperlipemic sera. A special antiserum reagent, consisting of a highly concentrated mixture of nonionic and anionic detergents (final concentration in the assay, 36 g/L), rapidly removes intrinsic turbidities of even strongly lipemic sera without interfering with the antigen-antibody precipitation reaction. The method has good precision, and obviates the need for special sample pretreatment, extended incubation periods, and measurment of sample blanks. A comparison with established immunoephelometric assays generally showed close agreement for analytical recoveries of the three apolipoproteins. However, in samples containing greater than or equal to 18 g of triglycerides per liter, the nephelometric assays yielded about two- to threefold higher values for apo A-II and B than did the turbidimetric procedure. To elucidate this discrepancy, we used the turbidimetric methods to assay sera with and without enzymatic lipolytic pretreatment. Even for samples with triglyceride concentrations up to 60 g/L, complete enzymatic lipolysis (as evidenced by thin-layer chromatography) did not significantly alter the recoveries of apo A-II and B from those obtained with the untreated specimens. Thus the immunoturbidimetric methods yield reliable results for apo A-I, A-II, and B, not only in normo- but also in hyperlipemic sera.

La lipémie postprandiale se caractérise par une augmentation des lipoprotéines riches en triglycérides après un repas, et joue un rôle important dans la biodisponibilité des lipides alimentaires pour les tissus périphériques. En effet, une lipémie postprandiale élevée est souvent associée à l'obésité et à une dyslipidémie, deux composantes du syndrome métabolique qui peuvent engendrer des complications médicales, incluant diabète et maladies cardiovasculaires. La lactoferrine (Lf) inhibe l'épuration hépatique des chylomicrons, conduisant à une élévation de la lipémie postprandiale par des mécanismes moléculaires non élucidés. Il est aussi établi que le Lipolysis Stimulated Receptor (LSR) contribuait à l'épuration des lipoprotéines riches en triglycérides pendant la phase postprandiale. L'objectif était de déterminer s'il existait une interaction entre la Lf et le LSR. Les études de cultures cellulaires ont montré que si la Lf n'affectait pas le taux d'expression du LSR dans des cellules Hepa 1-6 de souris, elle co-localisait avec le LSR en présence d'oléate, un composé requis pour l'activation du récepteur. Des expériences de ligand-blotting ont également montré que la Lf se fixait sur le LSR purifié et inhibait la fixation de lipoprotéines riches en triglycérides. Les domaines N et C-terminaux isolés de cette protéine, ainsi qu'un mélange de peptides obtenu après double hydrolyse de la Lf par la trypsine et la chymotrypsine, conservent cette propriété. Nous proposons que l'élévation de la lipémie postprandiale observée in vivo suite à un traitement par la Lf soit médiée par son interaction avec le LSR, inhibant ainsi l'épuration des chylomicrons et de leurs remnants
Postprandial lipemia is characterized by an increase in plasma triglyceride-rich lipoproteins after the ingestion of meal, and is important towards determining the bioavailability of dietary lipids amongst the peripheral tissues. Indeed, elevated postprandial lipemia is often observed with obesity and dyslipidemia, two disorders that can lead to health complications including diabetes and cardiovascular diseases. Lactoferrin (Lf), has been shown to inhibit hepatic chylomicron remnant removal, resulting in increased postprandial lipemia, for which the molecular mechanisms remain unclear. The lipolysis stimulated lipoprotein receptor (LSR) has been shown to contribute to the removal of triglycerides-rich lipoproteins during the postprandial phase. The aim was to determine if there was interaction between Lf and LSR. Both Lf and LSR were purified with purities upper to 95% and characterized. Cell culture studies demonstrated that while Lf does not have any significant effect on LSR protein levels in mouse Hepa1-6 cells, it co-localizes with LSR in cells, but only in the presence of oleate, which is needed to obtain LSR in its active form. Ligand blotting using purified LSR revealed that Lf binds directly to the receptor in the presence of oleate and prevents the binding of triglycerides-rich lipoproteins. Both C- and N-lobes of Lf, and a mixture of peptides derived from its tryptic and chymotryptic double hydrolysis retained the ability to bind LSR. We propose that the elevated postprandial lipemia observed upon Lf treatment in vivo is mediated by its direct interaction with LSR, thus preventing clearance of chylomicrons and their remnants through the LSR pathway

Dans cette thèse, nous avons voulu explorer des voies dites "clean-label" qui permettraient d'intégrer des mono- et diglycérides d'acides gras (MDGs ; E471) dans des matrices alimentaires. En effet, les fabricants cherchent des solutions pour remplacer les additifs obtenus par voie de synthèse tout en gardant les mêmes fonctionnalités dans les produits alimentaires. L'utilisation d'auxiliaires technologiques, comme les enzymes, entre parfaitement dans la démarche de produits plus respectueux du consommateur et de l'environnement ; c'est-à-dire "clean-label". Ainsi avec une lipase mise en contact avec de l'huile de colza, nous avons démontré que des MDGs pouvaient être générés in situ avec un bon rendement. Pour mieux comprendre les cinétiques de lipolyse et caractériser l'ensemble des produits formés, des analyses par chromatographie en phase gazeuse et RMN 1H et 13C ont été effectuées. Enfin, les huiles de colza, différemment enrichies en MDGs ont ensuite été utilisées dans la fabrication directe de produits alimentaires. En effet, sur chacun des produits choisis, les MDGs jouent des rôles différents. Des produits tels que des barres pâtissières, des brioches et des crèmes glacées ont donc été formulés et caractérisés afin de mettre en avant les effets technologiques et les différences par rapport à des produits fabriqués avec de l'huile de colza seule. Enfin, la fabrication d'émulsions inverses concentrées réalisée à partir de l'huile hydrolysée a été développée permettant d'entrevoir la possibilité de fabriquer des émulsions doubles
In this project, we wanted to explore "clean-label" strategies to incorporate mono- and diglycerides of fatty acids (MDGs; E471) in food products. Indeed, manufacturers try to find solutions in order to substitute synthetic additives while keeping the same functionalities in the food products. The use of processing aids, such as enzymes, fits perfectly with the approach of products that are more respectful of consumers and the environment; that is to say "clean-label". Thus, by reacting a lipase with rapeseed oil, we demonstrated that MDGs could be generated in situ and with a good yield. To better understand the kinetics of lipolysis and to characterize all the products formed, analysis by gas chromatography and 1H and 13C NMR were carried out. Finally, rapeseed oils with different MDGs rates, were used in the fabrication of different food products. Indeed, on each of the products chosen, the MDGs play different roles. Products like sponge cakes, brioches and ice creams were formulated and characterized to highlight all benefits comparatively to products made with unmodified rapeseed oil. Finally, the fabrication of concentrated reverse emulsions starting from the post-enzymatic oil has been developed that allow the possibility to obtain doubles emulsions

Tesis por compendio
[ES] De entre las metodologías disponibles para estudiar la digestión de alimentos, los modelos de digestión in vitro se plantean como procedimientos válidos para este propósito. La digestión in vitro consiste en simular el proceso de digestión en el laboratorio, reproduciendo las condiciones fisiológicas en cuanto a composición de los fluidos digestivos (electrolitos y enzimas), pH, temperatura, fuerzas mecánicas y duración de las etapas oral, gástrica e intestinal. Abordar el estudio de la digestión de nutrientes es de especial relevancia en patologías que cursan con alteraciones pancreáticas o hepáticas, asociadas a una digestión de lípidos comprometida en la etapa intestinal, debido a la disminución de secreción de pancreatina, bicarbonato y sales biliares. Este es el caso de la fibrosis quística con insuficiencia pancreática, y los pacientes que padecen esta afección deben seguir la terapia de sustitución de enzimas pancreáticas, que consiste en el suministro exógeno de pancreatina encapsulada. Sin embargo, la dosis de este suplemento debe ajustarse a las características de los alimentos y no se dispone de ningún método válido para tal fin. Para hacer frente a este reto, en el proyecto financiado con fondos europeos MyCyFAPP se ha logrado desarrollar un método para ajustar la dosis óptima de los suplementos enzimáticos utilizados en la terapia. La presente tesis doctoral se realizó en el marco de dicho proyecto. Concretamente, esta tesis tiene como objetivo abordar el estudio de la digestión de lípidos en los alimentos de origen animal (carne y productos cárnicos, huevos, queso y pescado) en el contexto de la fibrosis quística. Para abordar este objetivo se aplicó un modelo de digestión in vitro estático con el fin de explorar el papel de las características inherentes a los alimentos (estructura de la matriz alimentaria como resultado del procesado) y los factores relacionados con el individuo (pH, concentración de sales biliares y concentración de pancreatina) como factores determinantes de la lipólisis en alimentos de origen animal. A lo largo de los cuatro capítulos presentados, centrados en el huevo, la carne, el queso y el pescado, se presenta un diseño experimental común para estudiar la lipólisis, la proteólisis y la degradación de la matriz. En cada estudio, las diferentes técnicas de procesado aplicadas a los alimentos evaluados también permitieron evaluar el efecto de las propiedades inherentes a los alimentos en los resultados del estudio. Los resultados han contribuido al desarrollo de un nuevo método basado en la evidencia para optimizar la terapia de reemplazo de enzimas pancreáticas e informan a la comunidad científica sobre nuevos conocimientos en el comportamiento de diferentes alimentos sometidos al proceso de digestión.
[CA] De les metodologies disponibles per estudiar la digestió d'aliments, els models de digestió in vitro es plantegen com a procediments vàlids per a aquest propòsit. La digestió in vitro consisteix en simular el procés de digestió al laboratori, reproduint les condicions fisiològiques pel que fa a la composició dels fluids digestius (electròlits i enzims), pH, temperatura, forces mecàniques i durada de les etapes oral, gàstrica i intestinal. Abordar l'estudi de la digestió de nutrients és d'especial rellevància en patologies que cursen amb alteracions pancreàtiques o hepàtiques, associades a una digestió de lípids compromesa en l'etapa intestinal, a causa de la disminució de secreció de pancreatina, bicarbonat i sals biliars. Aquest és el cas de la fibrosi quística amb insuficiència pancreàtica. Els pacients que pateixen aquesta afecció han de seguir la teràpia de substitució d'enzims pancreàtics, que consisteix en el subministrament exogen de pancreatina encapsulada. No obstant això, la dosi d'aquest suplement ha d'ajustar-se a les característiques dels aliments i actualment no es disposa de cap mètode vàlid per a tal fi. Per enfrontar a aquest repte, en el projecte finançat amb fons europeus, MyCyFAPP, s'ha aconseguit desenvolupar un mètode per a ajustar la dosi òptima dels suplements enzimàtics utilitzats en la teràpia. La present tesi doctoral es va realitzar en el marc d'aquest projecte. Concretament, aquesta tesi té com a objectiu abordar l'estudi de la digestió de lípids en els aliments d'origen animal (ous, carn i productes carnis, formatge i peix) en el context de la fibrosi quística. Per a abordar aquest objectiu es va aplicar un model de digestió in vitro estàtic amb la finalitat d'explorar el paper de les característiques inherents als aliments (estructura de la matriu alimentària com a resultat del processament) i els factors relacionats amb l'individu (pH, concentració de sals biliars i concentració de pancreatina) com a factors determinants de la lipòlisi en aliments d'origen animal. Als quatre capítols presentats, centrats en l'ou, carn, formatge i peix, es presenta un disseny experimental comú per a estudiar la lipòlisi, la proteòlisi i la degradació de la matriu. En cada estudi, les diferents tècniques de processament aplicades als aliments avaluats també van permetre avaluar l'efecte de les propietats inherents als aliments en els resultats de l'estudi. Els resultats han contribuït al desenvolupament d'un nou mètode basat en l'evidència per a optimitzar la teràpia de substitució d'enzims pancreàtics i informen la comunitat científica sobre nous coneixements en el comportament de diferents aliments sotmesos al procés de digestió.
[EN] Among the available methodologies to study food digestion, in vitro digestion models have raised as a valid procedure. In vitro digestion consists of simulating the digestion process in the laboratory, by reproducing the physiological conditions in terms of digestive fluids composition (electrolytes and enzymes), pH, temperature, mechanical forces and duration of the oral, gastric and intestinal stages. Addressing the study of nutrient digestion is of special relevance in pathologies coursing with pancreatic or hepatic alterations, which are associated with compromised intestinal lipid digestion due to reduced secretion of pancreatin, bicarbonate and bile salts. This is the case of Cystic Fibrosis along with pancreatic insufficiency, and the patients suffering this condition have to follow pancreatic enzyme replacement therapy, the exogenous supply of encapsulated pancreatin. However, the dose of this supplement should be adjusted to the specific characteristics of foods, and no valid method was available for such purpose. To tackle this challenge, the EU-funded project MyCyFAPP succeed to develop a method to adjust the optimal dose the enzyme supplements used in the therapy. The present doctoral thesis was conducted as a relevant part of this project. Concretely, this thesis aims at addressing the study of lipid digestion in foods to generate new knowledge regarding nutrient digestion in animal origin dietary sources (egg, meat and meat products, cheese and fish) in the context of Cystic Fibrosis. To address this goal a static in vitro digestion model was applied. The role of inherent-to-food characteristics (resulting food matrix structure from processing) and host related factors (pH and bile salts concentration and pancreatin concentration) were explored as determinants of lipolysis in animal-origin foods. Along the four chapters presented, focused on egg, meat, cheese and fish, a common experimental design was applied to study lipolysis, proteolysis and matrix degradation. In each study, different processing techniques applied to the assessed foods allowed for evaluating the effect of inherent-to-food properties on the study outcomes as well. The results have contributed to the development of a new evidence-based method to optimise pancreatic enzyme replacement therapy, and inform the scientific community about new insights on the behaviour of different foods undertaking the digestion process.
Authors of this paper acknowledge the European Union and the Horizon 2020 Research and Innovation Framework Programme (PHC-26-2014 call Self-management of health and disease: citizen engagement and mHealth) for fully funding this research in the context of MyCyFAPP Project, under grant agreement number 643806. The authors would like to thank the Conselleria de Educació i Investigació de la Generalitat Valenciana and also the European Union (“El Fondo Social Europeo (FSE) invierte en tu futuro”) for the PhD scholarship given to Andrea Asensio Grau (ACIF/2017/008). This study was developed thanks to the equipment funded with the support from the Generalitat Valenciana IDIFEDER/2018/041 (PO FEDER Comunitat Valenciana 2014-2020). Finally, we thank Antonio Martínez Cañada, from the Data Science and Biostatistics Unit of Instituto de Investigación Sanitaria La Fe, and Arash Javanidejad for the English corrections.
Asensio Grau, A. (2021). In vitro approach of dietary and host related factors affecting digestion of animal-origin foods under cystic fibrosis disease [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/171512
TESIS
Compendio

Étude de la dégradation des lipides dans les sols : numération des microorganismes en cause, mesure de la disparition de matière grasse in situ, mesure de l'activité lipolytique de différents sols. L'activité lipolytique est intense dans les sols où on rencontre une accumulation de matière organique et ne présente pas une étape limitante dans le processus de minéralisation. Étude des microorganismes responsables de la lipolyse dans les produits carnes : bactéries et levures. Identification des bactéries les plus actives. Production d'enzymes lipolytiques par bacillus pumilus, caractérisation et purification de ces enzymes

As caprilinas são acilgliceróis de cadeia média com diversas aplicações nos campos alimentício, farmacêutico e cosmético. A esterificação direta é um processo importante para a síntese de caprilinas, dado que o glicerol é subproduto da produção de biodiesel e que a tricaprilina, material de partida para a glicerólise e hidrólise, não é um composto abundante naturalmente. As reações existentes para a síntese de acilgliceróis podem ser catalisadas por via química ou enzimática, sendo esta última superior em diversos aspectos. Dois dos principais contrapontos à utilização de enzimas são seu alto custo e dificuldade de recuperação. A imobilização de enzimas é uma das maneiras existentes para contornar estas questões. A maioria dos estudos científicos relativos à obtenção destes compostos refere-se aos acilgliceróis de cadeia longa. Portanto, é necessário aprimorar a esterificação direta entre o glicerol e ácido caprílico catalisada por lipase, através da compreensão da cinética reacional e da influência dos parâmetros reacionais. A existência de uma metodologia de separação, identificação e quantificação simples e eficaz também é importante, tornando as pesquisas relacionadas às caprilinas mais rápidas e menos complicadas. Desta maneira, este trabalho consistiu de três etapas principais: (1) a imobilização de lipases em resinas de troca aniônica, visando reduzir os custos em relação à lipase imobilizada comercial; (2) o desenvolvimento de um método de cromatografia em camada delgada capaz de quantificar as caprilinas formadas; (3) o estudo da reação de esterificação para a obtenção de caprilinas em regime descontínuo e descontínuo-alimentado. A resina DOWEX® 1X2-400 foi a que apresentou a melhor eficiência de imobilização (EI) da Palatase®. Sua atividade lipolítica foi apenas 12,7% inferior à versão imobilizada comercial da lipase, a Lipozyme®RM IM, indicando a viabilidade de substituição desta última. O desenvolvimento de método de cromatografia em camada delgada resultou em relações lineares para a detecção e quantificação de ácido caprílico, monocaprilina, dicaprilina e tricaprilina com R2 e R2pred de 99,3%/98,73%; 98,9%/97,6%; 99,8%/99,8% e 99,7%/99,5%, respectivamente, e com valor-p de 0,000. As reações em regime descontínuo foram realizadas seguindo planejamento fatorial completo, no qual foram variadas a temperatura (30 ou 70°C), a proporção molar entre os reagentes (1:1 ou 3:1 - ácido caprílico : glicerol) e o tempo reacional (6 ou 10h). A análise de regressão do rendimento reacional expresso em porcentagem de consumo de ácido caprílico indicou que, nestas condições, os fatores relevantes para o resultado final são a temperatura e a proporção molar, bem como a interação entre eles. As melhores condições para a obtenção de mono e dicaprilinas foram, portanto, de 30ºC e razão molar de 1:1. O estudo da cinética da reação indica que 40,4% do ácido caprílico são consumidos na primeira hora e que o consumo máximo ocorre na terceira hora de reação. Houve uma queda drástica no rendimento reacional, quando a reação foi conduzida em regime descontínuo-alimentado, provavelmente devido à menor eficiência catalítica da lipase devido ao baixo teor de água na primeira hora de reação.
Caprylins are medium chain acylglycerols that find several applications in food, pharmaceutical and cosmetic fields. Direct esterification is an important route for the synthesis of caprylins, since glycerol is a byproduct of biodiesel production and tricaprylin, the starting material of glycerolysis and hydrolysis, is not a naturally abundant compound. The glycerides synthesis can be catalyzed by either chemical or enzymatic routes, the latter being superior in several aspects. The biggest issues regarding the use of enzymes are their high cost and difficult recovery. Using immobilized enzymes can minimize these concerns. Most of scientific studies concerning the obtainment of these compounds address to long chain acyglycerols. Thus, the improvement of lipase catalyzed esterification of glycerol and caprylic acid is necessary, by understanding the reaction kinetics and the role of reaction parameters. A simple and effective method of separation, identification and quantification of caprylins is also a relevant contributing factor for easier and faster researches. Therefore, this work consisted of three main steps: (1) immobilization of lipases on anion exchange resins in order to produce a cheaper alternative to imported commercial immobilized lipases; (2) development of a thin layer chromatographic method capable of quantifying caprylins; (3) studying the obtainment of caprylins by direct esterification in batch and fed batch systems. DOWEX® 1X2-400 resin presented the best immobilization efficiency (IE) results. Additionally, its lipolytic activity was only 12.7% lower than the commercial Lipozyme® RM IM, suggesting that Lipozyme\'s substitution is feasible. Regarding the developing of a thin layer chromatography method, linear correlations were obtained for detection and quantification of caprylic acid, monocaprylin, dicaprylin and tricaprylin, with a R2 and R2pred of 99,3%/98,73%; 98,9%/97,6%; 99,8%/99,8% e 99,7%/99,5%, respectively, with a p-value of 0,000. The batch reactions were carried out according to a complete factorial design, in which the temperature (30 or 70ºC), the molar ratio between the reagents (1:1 or 3:1) and reaction time (6h or 10h) were varied. The regression analysis of reactional yield expressed in terms of percentage of caprylic acid consumption indicated that only the temperature, molar-ratio and their interaction were important for reaction yields, within the studied conditions. The best conditions related to the obtainment of mono and dicaprylins were 30ºC and molar ratio of 1:1. The reaction kinetics indicates that 40.4% of the caprylic acid is consumed within one hour of reaction and that the maximal consumption was achieved in the third hour. A drastic drop in reaction yield was observed when the fed batch mode was adopted, probably due a lower catalytic efficiency presented by lipase as a result of the lower water content in the first hour of reaction.

Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.18.06 – технологія жирів, ефірних масел і парфумерно-косметичних продуктів. – Національний технічний університет “Харківський політехнічний інститут” Міністерства освіти і науки України, Харків, 2004. Дисертацію присвячено розробленню науково обґрунтованої ферментної технології модифікування жирів. Доведено підпорядкованість дії ферменту, продуцентом якого є мікроорганізм Candida antarctica, кінетиці Міхаеліса-Ментен та знайдено відповідні кінетичні константи. Визначено раціональні умови дії ферментних препаратів Новозім 398 та Ліпозим TL IM при модифікуванні жирової сировини. Підтверджено можливість використання ферментного препарату Ліпозим RM IM для модифікування рослинних жирів шляхом ацидолізу. Досліджено кінетику ферментної переетерифікації та визначено математичну модель залежності ступеня перетворення вихідного компонента від часу. Встановлено кількісні залежності складу та властивостей продуктів ферментної переетерифікації від складу вихідної сировини. На основі визначених закономірностей створено технологію модифікування жирів за допомогою ферментів та рецептури ферментно переетерифікованих жирів. Одержано комплекс даних щодо органолептичних і фізико-хімічних характеристик отриманих модифікованих жирів. У результаті дослідно-промислових і промислових випробувань встановлено можливість одержання модифікованих жирів із заданими властивостями шляхом ферментної переетерифікації. За новою технологією на Вінницькому та Одеському олійно-жирових комбінатах вироблено 250 тон переетерифікованих жирів. Економічний ефект від її впровадження дорівнює більш ніж 50 грн/т.
Thesis for a candidate degree of technical sciences by speciality 05.18.06 – technology of fats, essential oils and perfume-cosmetic products.– National Technical University “Kharkov Polytechnic Institute” of Ministry of Education and Science of Ukraine, Kharkov, 2004. The dissertation is devoted to the making of the scientific proved enzyme technology of fats modification. It was proved that the action of enzyme from Candida antarctica obeys Michaelis-Menten kinetics. The appropriate kinetic constants were found. The efficient operation conditions were determined for the action of enzymatic preparations Novozym 398 and Lipozyme TL IM for fat stock modification. The possibility of application of enzymatic preparation Lipozyme RM IM for fats modification by means of acidolysis was vindicated. The enzymatic interesterification kinetics was investigated and the mathematical model of dependence of source component conversion degree on time was elaborated. The quantitative dependences of composition and characteristics of enzymatic interesterified products on feedstock composition were determined. On basis of regularities obtained the technology of fats modification using enzymes and the recipes of enzymatic interesterified fats were developed. The data complex was determined concerning organoleptic and physical-chemical characteristics of modified fats obtained. As a consequence of experimental-industrial and industrial tests the possibility of production of modified fats with predetermined characteristics by means of enzymatic interesterification was ascertained. According to the new technology 250 tons of interesterified fats were produced at Vinnitskiy and Odesskiy fat-and-oil industrial complexes. The economic effect of its application amounts to 50 grn/t and more.

Many different kinds of cultures, enzymes, and methods are used during the production and ripening of a variety of cheese types. In this chapter, the importance, types, and applications of microbial cultures during cheese production are discussed. Moreover, an overview of the important role of enzymatic systems, either derived from these cultures or directly added to the milk fermentation, is presented. The main biochemical events including glycolysis, lipolysis, and proteolysis during cheese ripening are explained, focusing on their end products, which contribute to the development of the overall aroma of cheese.

Understanding better how triacylglycerol (TAG) crystallinity alters lipid digestion should help to clarify the contributions of dietary lipids to postprandial lipemia. The static in vitro digestibility of o/w Span 60 emulsions with similarly sized (~ 500 nm in diameter) palm olein (PO) control or palm stearin (PS) droplets tempered to contain maximal (PS-SE) and partial (PS-SE-25 °C) crystallinity or to remain undercooled (PS-LE) at 37 °C was compared. With low shear and no preceding gastric phase, duodenal lipolysis quantified using a commercial enzymatic assay did not differ up to 10 minutes (p> 0.05) while particle size also did not differ (p> 0.05). Lipolysis then trended higher for the liquid emulsions (i.e., PO and PS-LE), but ultimately did not differ between samples. With low shear gastro-duodenal digestion, PO hydrolysis was unexpectedly lower compared to PS-SE and PS-LE throughout the duodenal phase potentially due to higher particle diameter and stabilizing effects of TAG crystallinity on colloidal properties. Higher shear in the gastro-duodenal digestion attenuated early lipolysis for all PS emulsions but not PO which was digested faster up to 60 minutes and differed from the other samples (p< 0.05). The results were related to differences in particle size such that the extra shear redispersed the acidic-flocculated PO droplets and this may have occurred to a lesser extent in the presence of crystalline TAG. The PS-LE sample, although liquid initially, experienced low level crystallization during digestion which led it to differ from the liquid control PO. Therefore, particle size measured during in vitro digestion indicated that TAG crystallinity differences affected colloidal behaviour and had an overall attenuating effect on lipid digestibility under the most physiologically relevant conditions. The work has relevance to postprandial lipemia since lipid digestibility may modulate lipemic response.

Enzymatic synthesis of bio-lubricant from (9Z)-octadecenoic acid with α-propylene glycol has been investigated in this article and the purpose of this study has been to find out the optimum reaction conditions of esterification. Lipolytic enzyme (Lipolase ®100L) has been used to catalyze esterification reaction in solvent-free systems. The optimum reaction conditions of esterification process were achieved. The assessment of the bio-lubricant production options was studied. Tribological properties of α-propylene glycol esters of (9Z)-octadecenoic acids as bio-lubricants were assessed.