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Keywords:

  • confocal laser scanning microscopy;
  • emulsion stability;
  • fat globule-size distribution;
  • flaxseed oil;
  • lipase-catalyzed interesterification;
  • modified butterfat

Abstract:  Modified butterfats (MBFs) were produced by lipase-catalyzed interesterification with 2 substrate blends (6:6:8 and 4:6:10, by weight) of anhydrous butterfat (ABF), palm stearin, and flaxseed oil in a stirred-batch type reactor after short path distillation. The 6:6:8 and 4:6:10 MBF contained 21.7% and 26.5%α-linolenic acid, respectively. Total saturated fatty acids of the MBFs ranged from 41.4% to 47.4%. The cholesterol contents of the 6:6:8 and 4:6:10 MBFs were 21.0 and 12.1 mg/100 g, respectively. In addition, the melting points of the 6:6:8 and 4:6:10 MBFs were 32 °C and 31 °C, respectively. After preparation of recombined milks (oil-in-water emulsions) with MBFs, the stability of emulsions prepared with the MBFs (6:6:8 and 4:6:10) was compared to those with ABF during 10-d storage at 30 °C. Skim milk powder (containing 1% protein) was added to prepare emulsions as an emulsifier. Microstructures of emulsions freshly prepared with the ABF and the MBFs consisted of uniform fat globules with no flocculation during 10-d storage. With respect to fat globule size distribution, the volume-surface mean droplet diameter (d32) of the 6:6:8 and 4:6:10 MBF emulsions ranged between 0.33 and 0.34 μm, which was similar to the distribution in ABF emulsion.

Practical Application:  Milk, an expensive dairy food, has been widely used in various milk-derived food products. Modified butterfats (MBFs) contain α-linolenic acid as an essential fatty acid. Emulsion stability of recombined milks (oil-in-water emulsions) with MBFs was similar to that in anhydrous butterfat emulsion during 10-d storage. They may be a promising alternative for reconstituted milks to use in processed milk-based products.