Progress 09/01/09 to 08/31/14
Outputs
Target Audience:
Nothing Reported
Changes/Problems: We found that structured lipids that contained polyunsaturated fatty acids were not stable after short path purification. In other words, some of the tocopherols and antioxdiants were lost. We added other experiments to find out what happened to the antioxidants and also find ways to stabilize the SLs and SLs in emulsions. This was a logical extension of the project that was not in the original objectives. We were successful as can be seen in the publications (Zou and Akoh, 2013, 2015). There was no addditional reporting requirements for this effort. What opportunities for training and professional development has the project provided? The PD and students were able to attend professional meetings to learn new things and present their work. This includes the Institute of Food Technologists (IFT), and the American Oil Chemists' (AOCS) annual meetings. How have the results been disseminated to communities of interest? Results have been presented at professional meetings and invited meetings both in the US and foreign countries such as Chile, China, Taiwan, Argentina, Brazil. Results were also published in research journals. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Human milk or infant formula is the only nutritional source of energy for an infant. Human milk fat (HMF) contains 3.0-4.5% fat with 98-99% of this fat in the form of triacylglycerols (TAGs). Infant formulas try to mimic the composition of fat found in breast milk for proper nutrition. However, most formulas are produced using vegetable oils that are rich in α-linolenic acid (ALA). Structured lipids (SLs) from high stearidonic acid (SDA) soybean oil pre-enriched with palmitic acid (PA) at the sn-2 position with Novozym 435 (NSL) or Lipozyme TL IM (LSL) from our previous research were further enriched with γ-linolenic acid (GLA) or docosahexaenoic acid (DHA). Small scale acidolysis reactions with Lipozyme TL IM were performed to determine the optimal reaction conditions as 1:1 substrate mole ratio of NSL or LSL to free DHA at 65oC for 24 h and a 1:0.5 substrate mole ratio of NSL or LSL to free GLA at 65oC for 12 h. Optimized SL products were scaled up in a 1 L stir-batch reactor, and the resulting SLs of NSL:DHA (NDHA), LSL:DHA (LDHA), NSL:GLA (NGLA) and LSL:GLA (LGLA) were chemically and physically characterized. The SLs contained over 54% PA at the sn-2 position with GLA over 8% for the GLA SLs and DHA over 10% for the DHA SLs. The oxidative stabilities of the SLs were increased by the addition of 200 ppm of TBHQ with NGLA being more stable due to higher tocopherol content than the other SLs. The melting and crystallization profiles did not differ between the DHA SLs or the GLA SLs. The TAG species were similar for the GLA SLs but differed between the DHA SLs with tripalmitin being the major TAG species in all SLs. High intakes of trans fatty acid (TFA) has been correlated with increased risk of several chronic diseases. n-3 FAs are positively associated with prevention and management of chronic diseases like cardiovascular and cancer. Enzymatic synthesis of trans-free structured margarine fat analogues from SDA soybean oil and high stearate soybean oil was optimized using response surface methodology (RSM). The independent variables considered were substrate molar ratio (2-5), temperature (50-65 °C), time (6-22 h), and enzymes (Lipozyme® TLIM and Novozym® 435). The dependent variables were mol% stearic acid incorporation and mol% SDA content. Desirable and optimal products composition were achieved at 50 °C, 18 h, 1:2, using Lipozyme TLIM, with 15.6 mol% stearic acid and 9.2 mol% SDA in the product and at 58 °C, 14 h, 1:2, using Novozym 435, with 14.8 mol% stearic acid and 6.4 mol% SDA. Using optimal conditions, SLs were synthesized in a 1 L stir-batch reactor and free fatty acids (FFAs) removed by short-path distillation. SLs were characterized for fatty acid profile, sn-2 positional fatty acids, triacylglycerol profile, polymorphism, thermal behavior, and solid fat content. The SLs had desirable fatty acid profile, physical properties, and suitable β' polymorph. The SL was compared to extracted fat (EF) from a commercial brand for FA profile, sn-2 positional FAs, TAG profile, polymorphism, thermal behavior, oxidative stability, and solid fat content (SFC). Both SL and EF had similar saturated FA (31 mol%) and unsaturated FA (68 mol%), but SL had a much lower n-6/n-3 ratio (1.1) than EF (5.8). SL had 10.5 mol% SDA. After short-path distillation, a loss of 53.9% was observed in the total tocopherol content of SL. The tocopherols were lost as free tocopherols. SL and EF had similar melting profile, β' polymorph, and oxidative stability. Margarine was formulated using SL (SLM) and EF (RCM, reformulated commercial margarine). No sensory difference was observed between the two margarines. These SLs could be used as margarine fat analogues and an alternative to partially hydrogenated fat. Other trans-free margarine fats were synthesized and characterized. The fate of endogenous vitamin E isomers during production and purification of structured lipids (SLs) was investigated. Two SLs involving tripalmitin, stearidonic acid soybean oil, and docosahexaenoic acid were synthesized by transesterification catalyzed by Novozym 435 (NSL) and acidolysis by Lipozyme TL IM (LDHA), and purified by short path distillation (SPD). The electron impact and chemical ionization mass spectra of tocopheryl and tocotrienyl fatty acid esters in the distillates measured by GC-MS in synchronous scan/SIM mode, demonstrated that these esters were formed during acidolysis as well as transesterification. The predominant esters were tocopheryl palmitate, tocopheryl oleate, and tocopheryl linoleate homologues and no tocopheryl or tocotrienyl linolenate, stearidonate, and docosahexaenoate was found. Meanwhile, none of these esters were detected in the residues for both NSL and LDHA. Less than 50% of vitamin E isomers were present in residues after SPD. This loss played a major role in the rapid oxidative deterioration of SLs from previous studies with less contribution from the formation of tocopheryl and tocotrienyl esters. The lost tocopherols and tocotrienols present at high concentration in the distillates may be recovered and used to improve the oxidative stability of SLs. The ability of natural antioxidant, annatto and palm tocotrienol-rich fractions (RTF), to inhibit lipid oxidation in SL-based infant formula emulsion was evaluated. Annatto RTF was more effective than palm TRF and α-tocopherol at 0.02% and 0.05%. We met all 3 objectives of the initial grant and more. The large amount of PA at the sn-2 position of all four SLs will allow for better absorption of PA and improved absorption of fat and calcium in infants. The stability of these SLs can be increased by the addition of TBHQ at 200 ppm for possible use as HMF analogues in infant formula. We were able to produce SLs containing SDA and no TFA with desirable polymorphism, thermal properties, and SFC for formulation of soft margarine. Most of the SLs produced in this study had desired properties of a margarine fat analogue and can be utilized for the production of trans-free margarine. This may help in reducing trans-fat intake in our diet while increasing n-3 FA intake. The fate of the tocopherols lost during the production and purification of SLs was elucidated using hyphenated techniques. Our results on antioxidants may lead to the development of natural antioxidant products for food applications. The infant formula fat analogues were also similar to human milk fat (HMF) in composition and physicochemical properties and should benefit infant nutrition. Results were presented at professional meetings annual meetings. Three graduate students (2 PhDs and 1 MS) were trained on this grant.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Zou, L. and Akoh, C.C. 2013. Characterisation and optimisation of physical and oxidative stability of structured lipid-based infant formula emulsion: effects of emulsifiers and biopolymer thickeners. Food Chem. 141:2486-2494.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Zou, L. and Akoh, C.C. 2015. Antioxidant activities of annatto and palm tocotrienol-rich fractions in fish oil and structured lipid-based infant formula emulsion. Food Chem. 168:504-511.
- Type:
Journal Articles
Status:
Under Review
Year Published:
2015
Citation:
Zou, L. and Akoh, C.C. 2014. Oxidative stability of structured lipid-based infant formula emulsion: effect of antioxidants.
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Progress 09/01/12 to 08/31/13
Outputs
Target Audience:
Nothing Reported
Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Students were able to attend and present their work at professional meetings such as the Institute of Food Technology and the American Oil Chemists' Society annual meetings. How have the results been disseminated to communities of interest? Results have been presented at professional meetings and published in research journals. What do you plan to do during the next reporting period to accomplish the goals? Studies on the infant formula emulsion and their stabilization will be investigated. Oxidation of the products will be studied. We will attempt to incorporate n-3 PUFA on to the phospholipids for infant formula use.
Impacts
What was accomplished under these goals?
Human milk or infant formula is the only nutritional source of energy for an infant. Human milk fat (HMF) contains 3.0-4.5% fat with 98-99% of this fat in the form of triacylglycerols (TAGs). Infant formulas try to mimic the composition of fat found in breast milk for proper nutrition. However, most formulas are produced using vegetable oils that are rich in α-linolenic acid (ALA). Structured lipids (SLs) from high stearidonic acid (SDA) soybean oil pre-enriched with palmitic acid (PA) at the sn-2 position with Novozym 435 (NSL) or Lipozyme TL IM (LSL) from our previous research were further enriched with γ-linolenic acid (GLA) or docosahexaenoic acid (DHA). Small scale acidolysis reactions with Lipozyme TL IM were performed to determine the optimal reaction conditions as 1:1 substrate mole ratio of NSL or LSL to free DHA at 65oC for 24 h and a 1:0.5 substrate mole ratio of NSL or LSL to free GLA at 65oC for 12 h. Optimized SL products were scaled up in a 1 L stir-batch reactor, and the resulting SLs of NSL:DHA (NDHA), LSL:DHA (LDHA), NSL:GLA (NGLA) and LSL:GLA (LGLA) were chemically and physically characterized. The SLs contained over 54% PA at the sn-2 position with GLA over 8% for the GLA SLs and DHA over 10% for the DHA SLs. The oxidative stabilities of the SLs were increased by the addition of 200 ppm of TBHQ with NGLA being more stable due to higher tocopherol content than the other SLs. The melting and crystallization profiles did not differ between the DHA SLs or the GLA SLs. The TAG species were similar for the GLA SLs but differed between the DHA SLs with tripalmitin being the major TAG species in all SLs. High intakes of trans fatty acid (TFA) has been correlated with increased risk of several chronic diseases. n-3 FAs are positively associated with prevention and management of chronic diseases like cardiovascular and cancer. Enzymatic synthesis of trans-free structured margarine fat analogues from SDA soybean oil and high stearate soybean oil was optimized using response surface methodology (RSM). The independent variables considered were substrate molar ratio (2-5), temperature (50-65 °C), time (6-22 h), and enzymes (Lipozyme® TLIM and Novozym® 435). The dependent variables were mol% stearic acid incorporation and mol% SDA content. Desirable and optimal products composition were achieved at 50 °C, 18 h, 1:2, using Lipozyme TLIM, with 15.6 mol% stearic acid and 9.2 mol% SDA in the product and at 58 °C, 14 h, 1:2, using Novozym 435, with 14.8 mol% stearic acid and 6.4 mol% SDA. Using optimal conditions, SLs were synthesized in a 1 L stir-batch reactor and free fatty acids (FFAs) removed by short-path distillation. SLs were characterized for fatty acid profile, sn-2 positional fatty acids, triacylglycerol profile, polymorphism, thermal behavior, and solid fat content. The SLs had desirable fatty acid profile, physical properties, and suitable β' polymorph. The SL was compared to extracted fat (EF) from a commercial brand for FA profile, sn-2 positional FAs, TAG profile, polymorphism, thermal behavior, oxidative stability, and solid fat content (SFC). Both SL and EF had similar saturated FA (31 mol%) and unsaturated FA (68 mol%), but SL had a much lower n-6/n-3 ratio (1.1) than EF (5.8). SL had 10.5 mol% SDA. After short-path distillation, a loss of 53.9% was observed in the total tocopherol content of SL. The tocopherols were lost as free tocopherols. SL and EF had similar melting profile, β' polymorph, and oxidative stability. Margarine was formulated using SL (SLM) and EF (RCM, reformulated commercial margarine). No sensory difference was observed between the two margarines. These SLs could be used as margarine fat analogues and an alternative to partially hydrogenated fat. Other trans-free margarine fats were synthesized and characterized. The fate of endogenous vitamin E isomers during production and purification of structured lipids (SLs) was investigated. Two SLs involving tripalmitin, stearidonic acid soybean oil, and docosahexaenoic acid were synthesized by transesterification catalyzed by Novozym 435 (NSL) and acidolysis by Lipozyme TL IM (LDHA), and purified by short path distillation (SPD). The electron impact and chemical ionization mass spectra of tocopheryl and tocotrienyl fatty acid esters in the distillates measured by GC-MS in synchronous scan/SIM mode, demonstrated that these esters were formed during acidolysis as well as transesterification. The predominant esters were tocopheryl palmitate, tocopheryl oleate, and tocopheryl linoleate homologues and no tocopheryl or tocotrienyl linolenate, stearidonate, and docosahexaenoate was found. Meanwhile, none of these esters were detected in the residues for both NSL and LDHA. Less than 50% of vitamin E isomers were present in residues after SPD. This loss played a major role in the rapid oxidative deterioration of SLs from previous studies with less contribution from the formation of tocopheryl and tocotrienyl esters. The lost tocopherols and tocotrienols present at high concentration in the distillates may be recovered and used to improve the oxidative stability of SLs.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2012
Citation:
Pande, G. and Akoh, C.C. 2012. Enzymatic synthesis of trans-free structured margarine fat analogues using stearidonic acid soybean and high stearate soybean oils. J. Am. Oil Chem. Soc. 89:1473-1484.
- Type:
Journal Articles
Status:
Published
Year Published:
2012
Citation:
Pande, G. and Akoh, C.C. 2012. Structured lipids in nutraceutical formulations. Inform 23:50-64.
Akoh, C.C. 2012. Biocatalysis: modifying lipids to advance food industry and human health. Inform 445-449.
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2012
Citation:
Enzymatic production of trans-free structured margarine fat analogs
- Type:
Journal Articles
Status:
Published
Year Published:
2012
Citation:
Pande, G., Akoh, C. C., and Shewfelt, R. L. 2012. Production of trans-free margarine with stearidonic acid soybean and high stearate soybean oils-based structured lipid. J. Food Sci. C1203-1210.
- Type:
Journal Articles
Status:
Published
Year Published:
2011
Citation:
Teichert, S.A. and Akoh, C.C. 2011. Modifications of stearidonic acid soybean oil by enzymatic acidolysis for the production of human milk fat analogues. J Agric. Food Chem. 59:13300-13310.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Pande, G. and Akoh, C.C. 2013. Enzymatic synthesis of trans-free structured margarine fat analogues with high stearate soybean oil and palm stearin and their characterization
LWT-Food Sci. Technol. 50:232-239.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Pande, G., Akoh, C. C., and Shewfelt, R. L. 2013. Utilization of enzymatically interesterified cottonseed oil and palm strearin-based structured lipid in the production of trans-free margarine. Biocat. Agric. Biotechnol. 2:76-84.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Zou, L. and Akoh, C.C. 2013. Identification of tocopherols and tocotrienols, and their fatty acid esters in residues and distillates of structured lipids purified by short path distillation. J. Agric. Food Chem. 61:238-246.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Pande, G. and Akoh, C.C. 2013. Enzymatic modification of lipids for trans-free margarine. Lipid Technol. 25:31-33.
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Progress 09/01/11 to 08/31/12
Outputs
OUTPUTS: Reduction of trans fatty acids (TFAs) in margarine and semi-solid fat containing products is of interest. Mean daily intake of TFA in USA is between 2-4%. Omega-3 FAs are associated with reduced risk of several chronic diseases. Stearidonic acid (SDA), is converted efficiently to eicosapentaenoic acid (EPA) than α-linolenic acid (ALA). SDA-enriched soybean oil (SDASO) is a sustainable plant source of n-3 PUFAs for food products. High stearate soybean oil (HSSO) was developed for increased stability in foods. The overall goal of this research project is to increase the possible applications of SDASO by producing structured lipids (SLs) suitable for trans-free margarines and infant formula. The specific objectives were to 1)characterize the physical and chemical properties of the SLs and compare with physical blends, and 2)to characterize SLs as human milk fat analog from the scaled-up SLs. SL1 was synthesized using Lipozyme TLIM and SL2 using Novozym 435. Corresponding physical blends (PB1 and PB2) were also prepared. SLs were purified by short-path distillation and characterized for sn-2 FAs, TAG molecular species, polymorphism, solid fat content (SFC), and melting and crystallization profiles. Each SL was compared with the physical blends produced under similar conditions. The wide range of fatty acid composition contributed to the predominant presence of the preferred β' crystal form. The SL prepared with Lipozyme TLIM (SL1) had 14.95 mol% stearic acid and 10.24 mol% SDA, whereas the physical blend (PB1) had 14.01 mol% stearic acid and 7.15 mol% SDA. For Novozym 435, the SL (SL2) had 15.97 mol% stearic acid and 8.89 mol% SDA while the physical blend (PB2) produced under similar conditions had 15.42 mol% stearic acid and 7.07 mol% SDA. SL1 had the highest SDA content with 9.23 mol% present at sn-2 position. About 7.94 and 11.47 mol% stearic acid was found at the sn-2 position of the SL1 and Sl2, respectively. Both SLs and PBs completely melted at room temperature. Compared to SDASO, the SLs showed broader peaks indicating a better plastic range which may be desirable for margarine. A desirable margarine is one that has < 32% SFC at 10˚C and <10% at room temperature. Both the SLs and PBs met these requirements. The SLs exhibited a more diverse TAG profile than the PBs. The major TAGs in SL1 were POL, LLL, and PLL and in PB1 were POL, PLL, and LLL. The predominant TAG species in SL2 were LLL, POL, and PLL and in PB2 were POL, LLL, and PLL. The SLs had more stearic acid containing TAGs than the PBs. Among all, SL1 showed the most dominant β' crystal form. For the human milk fat analogs, SLs were also characterized. SLs contained 8.15 and 8.38% total SDA and 60.84 and 60.63% PA at the sn-2 position for Novozym 435 SL and Lipozyme TL IM SL, respectively. The SLs were less oxidatively stable than SDASO after purification of the SLs. The saponification values of the SLs were slightly higher than the SDASO while melting profiles were similar. The TAG molecular species of the SLs were similar to each other with tripalmitin being the major TAG. There was no change in enzymatic activity after five reuses. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Our research will result in the production of trans-free margarine with added nutritional benefits. It can be used in the production of soft spreadable margarine. This research will also provide SLs that may be used in infant formula to increase the PA content at the sn-2 position and also contain a fair amount of SDA. Increased palmitic acid at the sn-2 position will allow for easy absorption of fat and calcium to reduce the formation of calcium soaps. SDA is used in the diet to increase omega-3 fatty acid intake and to help enrich the tissues with EPA. EPA is essential to growth, development, and intestinal absorption of fat-soluble vitamins in infants and is linked to reductions in inflammation and neurological disorders. Oil enriched in SDA was used instead of ALA, since SDA is more effective in converting to EPA. This is due to the fact that it is the intermediate between ALA and EPA. Results were presented at 2011 professional meeting and part of it will be presented in 2012 annual meetings. Two graduate students are being trained on this grant. Their contributions are helping us to achieve the objectives of this grant.
Publications
- Teichert, S.A. and Akoh, C.C. 2011. Modifications of stearidonic acid soybean oil by enzymatic acidolysis for the production of human milk fat analogues. J Agric. Food Chem. 59:13300-13310.
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Progress 09/01/10 to 08/31/11
Outputs
OUTPUTS: Reduction of trans fatty acids (TFAs) in margarine and semi-solid fat containing products is of interest. Mean daily intake of TFA in USA is between 2-4%. Omega-3 FAs are associated with reduced risk of several chronic diseases. Stearidonic acid (SDA), is converted efficiently to eicosapentaenoic acid (EPA) than α-linolenic acid (ALA). SDA-enriched soybean oil (SDASO) is a sustainable plant source of n-3 PUFAs for food products. High stearate soybean oil (HSSO) was developed for increased stability in foods. The overall goal of this research project is to increase the possible applications of SDASO by producing structured lipids (SLs) suitable for trans-free margarines and infant formula. The specific objectives were to 1)characterize the physical and chemical properties of the SLs and compare with physical blends, and 2)to characterize SLs as human milk fat analog from the scaled-up SLs. SL1 was synthesized using Lipozyme TLIM and SL2 using Novozym 435. Corresponding physical blends (PB1 and PB2) were also prepared. SLs were purified by short-path distillation and characterized for sn-2 FAs, TAG molecular species, polymorphism, solid fat content (SFC), and melting and crystallization profiles. Each SL was compared with the physical blends produced under similar conditions. The wide range of fatty acid composition contributed to the predominant presence of the preferred β' crystal form. The SL prepared with Lipozyme TLIM (SL1) had 14.95 mol% stearic acid and 10.24 mol% SDA, whereas the physical blend (PB1) had 14.01 mol% stearic acid and 7.15 mol% SDA. For Novozym 435, the SL (SL2) had 15.97 mol% stearic acid and 8.89 mol% SDA while the physical blend (PB2) produced under similar conditions had 15.42 mol% stearic acid and 7.07 mol% SDA. SL1 had the highest SDA content with 9.23 mol% present at sn-2 position. About 7.94 and 11.47 mol% stearic acid was found at the sn-2 position of the SL1 and Sl2, respectively. Both SLs and PBs completely melted at room temperature. Compared to SDASO, the SLs showed broader peaks indicating a better plastic range which may be desirable for margarine. A desirable margarine is one that has < 32% SFC at 10˚C and <10% at room temperature. Both the SLs and PBs met these requirements. The SLs exhibited a more diverse TAG profile than the PBs. The major TAGs in SL1 were POL, LLL, and PLL and in PB1 were POL, PLL, and LLL. The predominant TAG species in SL2 were LLL, POL, and PLL and in PB2 were POL, LLL, and PLL. The SLs had more stearic acid containing TAGs than the PBs. Among all, SL1 showed the most dominant β' crystal form. For the human milk fat analogs, SLs were also characterized. SLs contained 8.15 and 8.38% total SDA and 60.84 and 60.63% PA at the sn-2 position for Novozym 435 SL and Lipozyme TL IM SL, respectively. The SLs were less oxidatively stable than SDASO after purification of the SLs. The saponification values of the SLs were slightly higher than the SDASO while melting profiles were similar. The TAG molecular species of the SLs were similar to each other with tripalmitin being the major TAG. There was no change in enzymatic activity after five reuses. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Our research will result in the production of trans-free margarine with added nutritional benefits.It can be used in the production of soft spreadable margarine. This research will also provide SLs that may be used in infant formula to increase the PA content at the sn-2 position and also contain a fair amount of SDA. Increased palmitic acid at the sn-2 position will allow for easy absorption of fat and calcium to reduce the formation of calcium soaps. SDA is used in the diet to increase omega-3 fatty acid intake and to help enrich the tissues with EPA. EPA is essential to growth, development, and intestinal absorption of fat-soluble vitamins in infants and is linked to reductions in inflammation and neurological disorders. Oil enriched in SDA was used instead of ALA, since SDA is more effective in converting to EPA. This is due to the fact that it is the intermediate between ALA and EPA. Results were presented at 2011 professional meeting and part of it will be presented in 2012 annual meetings. Two graduate students are being trained on this grant. Their contributions are helping us to achieve the objectives of this grant.
Publications
- Teichert, S.A. and Akoh, C.C. 2011. Stearidonic acid soybean oil enriched with palmitic acid at the sn-2 position by enzymatic interesterification for use as human milk fat analogues. J. Agric. Food Chem. 59:5692-5701.
- Teichert, S.A. and Akoh, C.C. 2011. Characterization of stearidonic acid soybean oil enriched with palmitic acid produced by solvent-free enzymatic interesterification. J. Agric. Food Chem. 59:9588-9595.
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Progress 09/01/09 to 08/31/10
Outputs
OUTPUTS: Intake of high amounts of trans fatty acids (TFA) has been positively correlated with increased risk of coronary heart disease, inflammation, and cancer. The American diet contains low levels of omega-3 fatty acids. Stearidonic acid, SDA (18:4 n-3) is a metabolic intermediate between α-linolenic acid (ALA) and eicosapentaenoic acid (EPA) and converts more efficiently to EPA than ALA. SDA soybean oil contains approximately 20% SDA. Palmitic acid (PA) is found in breast milk at approximately 18.3-25.9% with over 60% by weight esterified at the sn-2 position. Our objective was to optimize the reaction conditions and blending ratios of substrates for trans-free structured margarine fat synthesis. We used palm stearin (PS), high stearate soybean oil (HSSO), and SDA-enriched soybean oil (SDASO) as substrates. For the human milk fat analog, we wanted to increase the PA content at the sn-2 position to over 60% by using tripalmitin and SDA soybean oil as substrates. Enzymatic synthesis of trans-free structured margarine fat analog from SDASO and HSSO; and HSSO and PS were optimized using response surface methodology (RSM). The independent variables considered for the design were substrate molar ratio (2-5), temperature (50-65 C), time (6-22 h), and enzyme (Lipozyme TL IM and Novozyme 435). A good-fit model was constructed using regression analysis with backward elimination and verified by a chi-square test. For combination SDASO and HSSO, time and mole ratio had a positive effect on the incorporation of stearic acid and temperature was found to have a negative effect. Among the enzymes, Novozyme 435 showed a positive effect whereas TL IM had a negative effect on stearic acid incorporation. For SDA, temperature and time were not significant factors but mole ratio and TL IM had a positive effect. At 50 C, 18 h, 1:2, using TL IM, optimal stearic acid incorporation (14.23 mol%) and SDA content of the product (7.03 mol%) were achieved. Optimal product was obtained at 58 C, 20 h, 1:2, using Novozyme 435, with 15.1 mol% stearic acid and 4.5 mol% SDA. For HSSO and PS combination, all linear parameters had a negative effect on the incorporation of stearic acid except Novozyme 435. Time was not significant but its interaction terms with temperature and mole ratio were significant. Optimal products with 8.92 and 11.23 mol% stearic acid were achieved at 57 C, 6.5 h, 1:2 with TL IM and 50 C, 20 h, 1:2 with Novozyme 435, respectively. For the human milk fat analog, the optimal conditions for a SL containing SDA and an increased amount of PA at the sn-2 position were a 1:2 mole ratio of SDA soybean oil to tripalmitin, reaction time of 18 h, and reaction temperature of 65 C. The free fatty acid content of the SLs was 0.40 and 0.35% with Novozyme 435 and Lipozyme TL IM, respectively. The SL had a SDA content of 8.15 and 8.38% and palmitic acid content at the sn-2 position of 60.84 and 60.63% with Novozyme 435 and Lipozyme TL IM, respectively. Results will be presented at 2011 professional meeting. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
This research will result in the production of trans-free margarine with added nutritional benefits and an optimized model adaptable for large scale synthesis of trans-free SL by the food industry to produce trans-free foods. The impacts of this research will result in providing a SL that may be used in infant formula to increase the palmitic acid content at the sn-2 position while containing SDA as a source of omega-3 fatty acid. Increased palmitic acid at the sn-2 position will allow for easy absorption of fat and calcium and reduce the formation of calcium soaps in infants. SDA is used in the diet to increase omega-3 fatty acid intake and to help enrich the tissues with EPA. EPA is essential to growth, development, and intestinal absorption of fat-soluble vitamins in infants and is linked to reductions in inflammation and neurological disorders. Oil enriched in SDA was used instead of ALA, since SDA is more effective in converting to EPA. This is due to the fact that it is the intermediate between ALA and EPA. Two graduate students are actively working on this proposal. Their contributions helped to achieve the goals of this grant.
Publications
- No publications reported this period
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