Produção de lipidios funcionais por ação de lipase fúngica
Resumo
A modificação estrutural de óleos e gorduras é uma das principais áreas de interesse
de pesquisa em diferentes setores industriais. No caso da indústria de alimentos, a
interesterificação é empregada para melhorar propriedades nutricionais e funcionais,
em que se obtêm compostos diferentes dos que lhes deram origem. As lipases
microbianas são os biocatalisadores mais utilizados industrialmente, por serem mais
estáveis, específicas e com propriedades bem mais diversificadas que as lipases de
outras fontes. Este trabalho objetivou, primeiramente, a caracterização da gordura da
pele de frango (GPF) e sua comparação com óleo de soja, como referência, visando a
utilização de GPF em reações de interesterificação. Para isto foram caracterizados
quanto aos índices de rancidez hidrolítica e oxidativa, bem como de matéria
insaponificável, índices de saponificação, refração e iodo. Foi realizado ainda o
fracionamento e perfil de ácidos graxos destes lipídios e suas frações, com o cálculo
de seus índices nutricionais. Foi verificado que a GPF apresentou qualidade
satisfatória devido aos baixos índices de acidez (0,65 g ácido oleico.100 g
-1
), peróxido
(2,14 meq.kg-1
), p-anisidina (0,70 unidades de absorvância.g-1
), além de fonte de
ácidos graxos mono-insaturados (40%), sendo fonte promissora para estudos de
interesterificação. Em um segundo momento o objetivo foi produzir lipídios modificados
ricos em ácidos graxos essenciais a partir da gordura da pele de frango e ácidos
graxos ramificados, utilizando lipase sn-1,3 específica e interesterificação do tipo
acidólise. Foram estudados os fatores concentração de enzima, adição de água,
proporção de substratos e tempo, segundo um planejamento experimental fatorial
completo 2
4
. As separações analíticas foram executadas em placas de cromatografia
de camada delgada, sendo as frações posteriormente extraídas, ressuspensas e
injetadas no cromatógrafo a gás. Foi verificado que a adição de água ao meio
reacional apresentou efeito significativo (p<0,05) para todos ácidos graxos avaliados
dos triacilgliceróis, sendo que para o ácido essencial linoleico (C18:2) o efeito do
tempo de reação também foi significativo, sendo verificado que quanto maior o tempo
de reação, menor a quantidade de água a ser adicionada. Em um terceiro momento, o
objetivo foi produzir éster fenólico a partir do DHCA, além de realizar reações de
transesterificação deste éster com tricaprilina. Para a reação de transesterificação, foi
utilizado um delineamento composto central rotacional (DCCR) variando a quantidade
de enzima, tempo de reação e temperatura sobre a resposta (%) dos reagentes
consumidos. A lipase Novozym® 435 de Candida antarctica foi utilizada como
catalisador de todas reações. Foi verificado que a maior produção de éster (50%)
ocorreu em oito dias. Nas reações de transesterificação, as relações molares em que
houve maior consumo do éster produzido foram 1:5 e 1:10, sendo obtidos 21,1% e
29,6% de residual de dihidrocafeato de octila, respectivamente em 24 h. Foi observado
que em altas temperaturas e tempo superior a 26 h, houve o menor residual de
dihidrocafeato de octila (18,2%). Foram identificados três diferentes compostos
fenólicos, contendo em sua estrutura dihidrocafeato de octila e ácido caprílico.
The structural modification of oils and fats is one of the main areas of research interest in different industrial sections. In relation to Food Industry, interesterification is used to improve nutritional and functional properties, in which different compounds are obtained from those who gave them origin. Industrially, microbial lipases are the most widely used biocatalysts, once they are more stable, specific and they have much more diversified properties than lipases from other sources. This work aimed at characterizing oils and fats from low cost to study their use for further interesterification reactions. Therefore, the physico-chemical composition was carried out together with the fatty acid profile of chicken skin fat (CSF) and soybean oil. For that, determination of oxidative and hydrolytic rancidity was accomplished as well as other indexes such as iodine, saponification, refraction and unsaponified matter, besides the glycerides fractionation, followed by fatty acids methyl esters derivatization and identification by Gas Chromatography. The nutritional quality indexes were then calculated. GPF showed satisfactory quality due to low acidity (0.65 g oleic acid.100 g -1 ), peroxide (2.14 meq.kg-1 ), p-anisidine (0.70 absorvance units.g-1 ) values. Besides that, CSF presented high proportion of monounsaturated fatty acids (40%), being a promising residue for different purposes, like interesterification reactions and biodiesel production. In a second moment, the goal was to produce modified lipids rich in essential fatty acids from CSF and branched fatty acids using sn-1,3 specific lipase and interesterification type acidolysis. The studied factors were enzyme concentration, water addition, substrate molar ratio and time, according to a 24 complete factorial design. The analytical separations were performed on thin layer chromatography plates, being the fractions extracted, resuspended and injected into the gas chromatograph. It was observed that water addition to the reaction medium had a significant effect (p<0.05) for all fatty acids from triacylglycerol, and for the essential linoleic acid (C18:2) the effect of reaction time was also significant, that is, the longer the reaction time, the lower the amount of water that’s needed. In a third moment, the goal was to produce phenolic ester from DHCA, besides carrying out transesterification reactions of this ester with tricaprilyn. For transesterification reaction, a central composite rotational design (CCRD) was accomplished, varying the amount of enzyme, reaction time and temperature on the response (%) of the reactants consumption. The Novozym ® 435 lipase from Candida antarctica was used as a catalyst for all reactions. It was found that the highest yield of ester (50%) occurred in eight days. In transesterification reactions, the molar proportions of higher ester consumption were 1:5 and 1:10, obtaining 21.1% and 29.6% respectively of octyl dihidrocaffeate residual in 24 h. The contour plots showed that at higher temperatures and time longer than 26 h, octyl dihidrocaffeate residual was the lowest (18.2%). Three different phenolic compounds, containing in its structure octyl dihidrocaffeate and caprylic acid were also identified.
The structural modification of oils and fats is one of the main areas of research interest in different industrial sections. In relation to Food Industry, interesterification is used to improve nutritional and functional properties, in which different compounds are obtained from those who gave them origin. Industrially, microbial lipases are the most widely used biocatalysts, once they are more stable, specific and they have much more diversified properties than lipases from other sources. This work aimed at characterizing oils and fats from low cost to study their use for further interesterification reactions. Therefore, the physico-chemical composition was carried out together with the fatty acid profile of chicken skin fat (CSF) and soybean oil. For that, determination of oxidative and hydrolytic rancidity was accomplished as well as other indexes such as iodine, saponification, refraction and unsaponified matter, besides the glycerides fractionation, followed by fatty acids methyl esters derivatization and identification by Gas Chromatography. The nutritional quality indexes were then calculated. GPF showed satisfactory quality due to low acidity (0.65 g oleic acid.100 g -1 ), peroxide (2.14 meq.kg-1 ), p-anisidine (0.70 absorvance units.g-1 ) values. Besides that, CSF presented high proportion of monounsaturated fatty acids (40%), being a promising residue for different purposes, like interesterification reactions and biodiesel production. In a second moment, the goal was to produce modified lipids rich in essential fatty acids from CSF and branched fatty acids using sn-1,3 specific lipase and interesterification type acidolysis. The studied factors were enzyme concentration, water addition, substrate molar ratio and time, according to a 24 complete factorial design. The analytical separations were performed on thin layer chromatography plates, being the fractions extracted, resuspended and injected into the gas chromatograph. It was observed that water addition to the reaction medium had a significant effect (p<0.05) for all fatty acids from triacylglycerol, and for the essential linoleic acid (C18:2) the effect of reaction time was also significant, that is, the longer the reaction time, the lower the amount of water that’s needed. In a third moment, the goal was to produce phenolic ester from DHCA, besides carrying out transesterification reactions of this ester with tricaprilyn. For transesterification reaction, a central composite rotational design (CCRD) was accomplished, varying the amount of enzyme, reaction time and temperature on the response (%) of the reactants consumption. The Novozym ® 435 lipase from Candida antarctica was used as a catalyst for all reactions. It was found that the highest yield of ester (50%) occurred in eight days. In transesterification reactions, the molar proportions of higher ester consumption were 1:5 and 1:10, obtaining 21.1% and 29.6% respectively of octyl dihidrocaffeate residual in 24 h. The contour plots showed that at higher temperatures and time longer than 26 h, octyl dihidrocaffeate residual was the lowest (18.2%). Three different phenolic compounds, containing in its structure octyl dihidrocaffeate and caprylic acid were also identified.
Descrição
Palavras-chave
Lipídios funcionais, Lipídios modificados, Ácido dihidrocafeico, Óleo de soja, Pele de frango, Índices de qualidade lipídica, Functional lipids, Modified lipids, Dihydrocaffeic acid, Soybean oil, Chicken skin, Lipid quality indexes
Citação
FEDDERN,Vivian. Produção de lipídios funcionais por ação de lipase fúngica.2010. 222 f. Tese (Doutorado em Engenharia e Ciência de Alimentos) - Escola de Química e Alimentos, Universidade Federal do Rio Grande. Rio Grande, 2010.