title: Iron-lactoferrin complex reduces iron-catalyzed off-flavor formation in powdered milk with added fish oil.
abstract: The iron-lactoferrin complex (FeLf) is useful for dietary iron supplementation. However, the effects of FeLf on iron-catalyzed off-flavors in lipid-containing food products have not been reported. In this study, we investigated the effects of FeLf on off-flavors development during the production and storage of powdered milk with added fish oil. Powdered milk samples were formulated with FeLf or iron (II) sulfate, then stored at 37 °C for 5 mo. A sensory evaluation revealed that FeLf delayed the development of oxidized flavor and reduced metallic taste in the powdered milk compared with iron (II) sulfate. Headspace gas chromatography-mass spectrometry analysis showed that oxidized volatile compounds, such as pentanal, hexanal, heptanal, octanal, 1-penten-3-one, (Z)-4-heptenal, (E, E)-2,4-heptadienal, and (E)-2-octenal, were less developed in the powdered milk containing FeLf than in that containing iron (II) sulfate. Iron and lactoferrin (Lf) were retained in the high-molecular-weight (>10000 Da) fraction of the reconstituted FeLf-containing powdered milk after its manufacture and storage, whereas the antigenicity of Lf was lost after ultrahigh-temperature processing at 120 °C for 5 s. These results suggest that FeLf reduces the iron-catalyzed off-flavors that develop during the production and storage of powdered milk. The stable iron-holding property of FeLf contributes to the inhibition of oxidized and metallic volatile formation, although the loss of Lf antigenicity did not affect the stability of FeLf and the iron-catalyzed formation of off-flavors in the powdered milk. Consequently, FeLf is a suitable candidate for the simultaneous supplementation of a single food with iron and fish oil.
  
  
  CONCLUSIONS
  The supplementation of food products with iron and fish oil is a useful approach to redressing their inadequate intake in many populations. The iron-lactoferrin complex can protect food products against the off-flavors caused by iron-catalyzed lipid oxidation. Our results show that the iron-lactoferrin complex is useful for the simultaneous fortification of foods and nutraceuticals with iron and fish oil because this complex also reduces the formation of iron-catalyzed off-flavors in powdered milk enriched with fish oil.
authors.affiliation: Milk Science Research Institute, Megmilk Snowbrand Co., Ltd, Kawagoe, Saitama, Japan.
authors.forename: Hiroshi M
authors.initials: HM
authors.lastname: Ueno
authors.forename: Makoto
authors.initials: M
authors.lastname: Shiota
authors.forename: Noriko
authors.initials: N
authors.lastname: Ueda
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Isogai
authors.forename: Toshiya
authors.initials: T
authors.lastname: Kobayashi
mesh_terms: D000447:Aldehydes / Q000032:analysis; D000818:Animals; D002384:Catalysis; D019587:Dietary Supplements; D005395:Fish Oils / Q000032:analysis*; D005511:Food Handling / Q000379:methods; D008401:Gas Chromatography-Mass Spectrometry; D019266:Iron, Dietary / Q000008:administration & dosage* / Q000378:metabolism; D007781:Lactoferrin / Q000008:administration & dosage*; D008892:Milk / Q000737:chemistry*; D013649:Taste; D055549:Volatile Organic Compounds / Q000032:analysis
chemical_list: D000447:Aldehydes; D005395:Fish Oils; D019266:Iron, Dietary; D055549:Volatile Organic Compounds; C057348:2-octenal; C046204:heptanal; C010463:n-hexanal; C046012:pentanal; D007781:Lactoferrin