Interesterification of milkfat with soybean oil catalysed by Rhizopus oryzae lipase immobilised on SiO(2)-PVA on packed bed reactor

The potential of the lipase from Rhizopus oryzae immobilised on SiO(2)-PVA to catalyse the interesterification of the milkfat with soybean oil in a packed bed reactor running on continuous mode was evaluated. The reactor operated continuously for 35 days at 45 degrees C, and during 12 days, no significant decrease in the initial lipase activity was verified. Interesterification yields were in the range from 35 to 38% wt, which gave an interesterified product having 59% lower consistency in relation to non-interesterified blend. Results showed the potential of the lipase from Rhizopus oryzae to mediate the interesterification of milkfat with soybean oil in packed bed reactor, attaining a more spreadable product under a cool temperature. The biocatalyst operational stability was assessed and an inactivation profile was found to follow the Arrhenius model, revealing values of 34 days and 0.034 day(-1), for half-life and a deactivation coefficient, respectively.

Compositional and textural properties of milkfat-soybean oil enzymatic interesterification

Milkfat-soybean oil blends were enzymatically interesterified (EIE) by Aspergillus niger lipase immobilized on SiO(2)-PVA hybrid composite in a solvent free system. An experimental mixture design was used to study the effects of binary blends of milkfat-soybean oil (MF:SBO) at different proportions (0:100; 25:75; 33:67; 50:50; 67:33; 75:25; 100:0) on the compositional and textural properties of the EIE products, considering, as response variables, the interesterification yield (IY), consistency and hardness. Lipase-catalysed interesterification reactions increased the relative proportion of TAGs` C(46)-C(52) and decreased the TAGs` C(40)-C(42) and C(54) concentrations. The highest IY was attained (10.8%) for EIE blend of MF:SBO 67:33 resulting in a more spreadable material at refrigerator temperature in comparison with butter, milkfat or non-interesterified (NIE) blend. In this case, consistency and hardness values were at least 32% lower than values measured for butter. Thus, using A. niger lipase immobilized on SiO(2)-PVA improves the textural properties of milkfat and has potential for development of a product incorporating unsaturated and essential fatty acids from soybean oil. (C) 2010 Elsevier Ltd. All rights reserved.

Interesterification of milkfat and soybean oil blends catalyzed by immobilized Rhizopus oryzae lipase

Milkfat (MF)/soybean oil (SBO) blends ranging from 50% to 100% of milkfat (w/w) were enzymatically interesterified with a sn-1,3 specific lipase from Rhizopus oryzae immobilized on polysiloxane-polyvinyl alcohol matrix, in a solvent free medium. Interesterification progress was monitored by following the changes in the relative proportions of 50-carbon triacylglycerols (TAGS) to 44-carbon TAGs (50/44 ratio) in the reaction. The starting materials and products were also analyzed in terms of consistency measured in a texturometer. All reactions gave interesterified (IE) products with lower consistency than non-interesterified (NIE) MF:SBO blends and interesterification degree varied from 0.54 to 2.60 in 48 h reaction. The highest interesterification degree was achieved for 65:35 MF:SBO blends, which gave 76% reduction in the consistency. These results showed the potential of the immobilized lipase to change the TAGs profile of the MF:SBO blend allowing to obtain cold-spreadable milkfat. (C) 2010 Elsevier B.V. All rights reserved.

Synthesis of Structured Lipids by Enzymatic Interesterification of Milkfat and Soybean Oil in a Basket-Type Stirred Tank Reactor

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Continuous enzymatic interesterification of milkfat with soybean oil produces a highly spreadable product rich in polyunsaturated fatty acids

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Lipídios modificados obtidos a partir de gordura do leite, óleo de girassol e ésteres de fitosteróis para aplicação em spreads

The objective of this paper was to evaluate the modifications in milkfat properties with the addition of sunflower oil (SO) and phytosterol esters (PE) and chemical interesterification. Fatty acid composition, softening point and consistency were determined. The saturation degree of milkfat decreased with the addition of SO and PE. Consequently, milkfat presented lower softening point and consistency. Chemical interesterification caused an increase in softening point due to the formation of higher amounts of trissaturated triacylglycerols with rearrangement. The incorporation of unsaturated fatty acids from SO and PE by milkfat triacylglycerols after chemical reaction caused linearization of consistency curves.

Modificação bioquímica da gordura do leite

Recent advances for improving physicochemical and nutritional properties of lipids are reviewed, with emphasis on products attaining by biochemical processing of natural fats and oils. Enzymatic interesterification provides an important route to modify physical and nutritional properties of milkfat without generating trans isomers. This process makes use of lipases, a versatile class of enzyme that is able to perform efficiently the target modification in both solvent and solvent free systems. The present review covers important features of lipases, lipase-catalyzed interesterification reactions and their effects on the composition and texture of the resulting product.

Testing for fat in milk by the Babcock test /

Cover title.

Carotin, the principal natural yellow pignment of milk fat.

Bibliography: p. 334-336.

Butterfat sampling and testing problems : a nine-market study /

Literature cited: p. 59-60.

A chemical and physical study of the large and small fat globules in cows' milk /

"January 11, 1909."

Lipoprotein lipase and lipolysis in milk

Bovine milk contains a lipoprotein lipase that accounts for most, if not all, of its lipolytic activity. The total lipase activity in raw milk is sufficient to cause rapid hydrolysis of a large proportion of the fat. However, in reality this does not happen, because the lipase is prevented from accessing the fat by the milkfat globule membrane. Physical damage to this membrane in raw milk initiates lipolysis. Furthermore, simply cooling certain individual milks soon after secretion can initiate the so-called spontaneous lipolysis. The biochemical basis of spontaneous lipolysis is still poorly understood, but it appears to be related to a balance between activating and inhibiting factors in the milk. Lipolysis in milk and milk products causes rancid off-flavours and other problems, and is a constant concern in the dairy industry. A thorough understanding of the mechanism of lipolysis and constant vigilance by operatives is required to minimize lipase-related problems. (c) 2006 Elsevier Ltd. All rights reserved.