The effects of dairy processes and storage on insulin-like growth factor-I (IGF-I) content in milk and in model IGF-I-fortified dairy products.
The effects of several dairy processes on insulin-like growth factor-I (IGF-I) concentrations in milk and the storage stability of IGF-I-fortified dairy products were examined. The IGF-I content in raw milk determined by radioimmunoassay was significantly changed by the strength of heat treatments. In commercial manufacture of whole milk dry powder, IGF-I concentration was not significantly changed. A significant reduction in IGF-I content was found as the result of fermentation with a commercial starter culture. The IGF-I content in fortified milk and dried milk powder exhibited no significant changes over the tested storage periods (12 d for milk, 4 wk for dried milk powder), but the IGF-I content in the yogurt decreased significantly during storage. The use of IGF-I was varied by lactic strains and was apparent in the viable cells. When IGF-I was encapsulated using the surface-reforming process, the remaining IGF-I content after fermentation was significantly higher compared with that of the untreated control. Therefore, enteric coating of IGF-I before fermentation might be an effective method for the prevention of IGF-I degradation during fermentation.
Kang
S H
SH
Institute of Dairy Food Research, Seoul Dairy Cooperative, Ansan 425-838, Korea.
Kim
J U
JU
Imm
J Y
JY
Oh
S
S
Kim
S H
SH
D000818:Animals; D003611:Dairy Products / Q000032:analysis*; D005285:Fermentation; D005511:Food Handling / Q000379:methods*; D005519:Food Preservation / Q000379:methods*; D005527:Food, Fortified / Q000032:analysis*; D006358:Hot Temperature; D007334:Insulin-Like Growth Factor I / Q000032:analysis* / Q000648:ultrastructure; D007778:Lactobacillus / Q000378:metabolism; D008892:Milk / Q000737:chemistry*; D015014:Yogurt / Q000032:analysis
D007334:Insulin-Like Growth Factor I