채유시기 및 저장상태에 따른 모유의 항산화능의 변화

Abstract

Background : Human milk is widely accepted as optimal for human infants' nutrition. Human milk contains various bioactive compounds. Breast milk antioxidant is important to perterm infants because preterm infants have reduced antioxidant capacity and often exposed to oxidant stress caused by infection, oxygen, mechanical ventilation and intraveous nutrition. For feeding preterm infants, human milk is usually expressed and stored before use. But change in antioxidant capacity of human milk with storage have not been well studied. The objective of this study was to measure antioxidant activity of fresh human milk in comparison with milk stored at refrigerator temperature(4℃) or freezer temperature(-20℃, -70℃) for 2nd to 7th days after storage. In addition, we compared the antioxidant capacity of milk according to gestational age and the difference of antioxidant capacity between colustrum, transient milk, mature milk. Method : Sixty breast milk samples were collected from mothers and divided to 7 tubes. Fresh samples were immediately tested for antioxidant activity, and antioxidant activity was compared according to gestational age and measured the difference of antioxidant capacity between colustrum, transient milk, mature milk. The rest of tubes were stored at 4℃, -20℃, -70℃ to be analysed at two days and seven days. The assay used measures the ability of milk samples to inhibit the oxidation of 2,2'-azino-di-3-ethylbenzthiazolinesulphonate to its radical cation compared with Trolox. Results : There is no relationship between antioxidant capacity and gestation age. Antioxidant capacity is not different according to colostrum and mature human milk. And antioxidant capacity at 4℃, -20℃, -70℃ storage was significantly decreased on both two days and seven days. There is no difference with decreased antioxidant capacity at 4℃, -20℃, -70℃ storage. Antioxidant capacity at seven days after storage is lower than that at two days after storage. Conclusion : To preserve the antioxidant of human milk, new method of storage should be studied and the method of supplement for decreased antioxidant capacity should be designed.