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Continuous enzymatic interesterification of milkfat with soybean oil produces a highly spreadable product rich in polyunsaturated fatty acids
Author(s) -
Paula Ariela V.,
Nunes Gisele F. M.,
Osório Natália M.,
Santos Júlio C.,
de Castro Heizir F.,
FerreiraDias Suzana
Publication year - 2015
Publication title -
european journal of lipid science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.614
H-Index - 94
eISSN - 1438-9312
pISSN - 1438-7697
DOI - 10.1002/ejlt.201400316
Subject(s) - interesterified fat , butterfat , rhizopus oryzae , chemistry , lipase , soybean oil , triacylglycerol lipase , candida antarctica , food science , flavor , chromatography , immobilized enzyme , organic chemistry , enzyme , linseed oil , milk fat , fermentation
The aim of this study was to tune the physical properties of milkfat by enzymatic interesterification with soybean oil in a continuous fluidized bed reactor (FBR) to obtain healthy interesterified fat blends having suitable texture properties for the food industry. The immobilized commercial non‐regioselective Candida antarctica lipase (Novozym®435) and sn 1,3‐regioselective Rhizopus oryzae lipase, immobilized in an organic‐inorganic hybrid matrix of polysiloxane‐polyvinyl alcohol, were used as biocatalysts in a FBR. The minimum value of the ascendant flow of the medium for allowing fluidization in the system was 3.13 mL·min −1 . The reaction was evaluated in terms of the interesterification yield (IY), consistency values and solid fat content (SFC). The IY values of 10.50 ± 1.64% and of 5.70 ± 1.46% were attained for Novozym®435 and for immobilized R. oryzae lipase, respectively. The consistency of the initial 65:35 milkfat/soybean oil mixture (1000 gf/cm 2 ) decreased to 732.35 ± 75.30 gf/cm 2 and to 478.02 ± 71.80 gf/cm 2 in interesterified blends catalyzed by Novozym®435 or by R. oryzae lipase, respectively. SFC was considered an inadequate parameter for following the interesterification of this blend formulation because the values were similar for initial and for interesterified blends. Free fatty acid levels of 1.5%, the non‐notable deactivation of Novozym®435 and a half‐life of 190 h for R. oryzae lipase were observed during the operation time. Practical applications: By interesterification of milkfat with soybean oil, a new product presenting higher spreadability than butter and richer in polyunsaturated fatty acids coming from soybean oil, was obtained. The Rhizopus oryzae lipase immobilized in an organic‐inorganic hybrid matrix, used in a FBR for the modification of milkfat, promoted a higher reduction (approximately 52.0%) in the consistency of the interesterified products in relation to the initial reaction mixture than that obtained with Novozym® 435 (approximately 27.0% reduction). Also, while Novozym® 435 is as a non‐specific lipase, the R. oryzae lipase presents sn ‐1,3 regioselectivity, which enables the maintenance of the unsaturated fatty acids at position sn ‐2 in triacylglycerols with well‐known nutritional benefits. This biocatalyst showed a better performance than the immobilized commercial lipase (Novozym® 435). The implementation of the interesterification in a continuous FBR results in lower shear rate imposed on the biocatalyst. The consistency of the initial milkfat/soybean blend (65:35,% w/w) decreased about 52% or 27% after interesterification in a continuous fluidized bed reactor, catalyzed by the immobilized Rhizopus oryzae lipase or by Novozym 435, respectively.