Studies Of Fortified Folic Acid In Liquid Milk

Folic acid is a water-soluble B vitamin. It involved in nucleic acid and protein biosynthesis, and plays an important role in cell division and growth of the individual. Deficiency of folat could cause fetal neural tube defects if folic acid lacked, and also elevate the congenital malformation of eyes, mouth, lips, palate, stomach, intestine, heart, kidney, bone and other organs. Daily folate supplement of 0.4mg in pregnant women for three months before and after pregnancy can prevent fetal neural tube defects and other congenital malformations. Fluid milk which is rich in vitamins can provide a variety of nutrients for pregnant women and infants, and also is the good carrier for folic acid fortification. This paper studied the fortification technology as following three parts:1. Study on the stability of folic acidObjective: To determine the stability of folic acid on the conditions of different pH, temperature, light, presence of antioxidants. Methods: RP-HPLC was applied to determine the stability of folic acid to different of pH, heat, light and the protective effect of antioxidants for folic acid. Results:①Folic acid showed a good stability in the buffer of pH from 6.35 to 10.13. The reservation ratio reached more than 94.5% in 96h. However, the preservation ratio reduced by 13% 96h later in buffer of pH4.13.②The loss ratio of folic acid was 0.1% after waterbath at 85℃for 30min, but the loss ratio rose rapidly to 44.8% after treated at 121℃for 15min.③The content of folic acid after exposure is less than the samples kept from light. The recovery ratio was 92.3% after exposure to the light intensity of 1000.④The antioxidants, such as VC,β-sparse ball ethanol, display a significant effect of protecting folic acid from oxidation. Conclusions: The factors including pH and light influenced the stability of folic acid severely. The preservation ratio seems not affected by a proper sterilization temperature. Adequate level of antioxidant would protect folic acid from oxidation effectively.2. Establishment of a RP-HPLC method for detection of folic acid in fluid milkObjective: To establish the method for detection of folic acid in fluid milk. Methods: RP-HPLC was used to determine the content of folic acid, in which the mobile phase was methanol-pH6.3 potassium dihydrogen phosphate (5:95) and the flow rate was 1.0mL/min, column temperature was at 30℃. The external standard method was used to determine the content of folic acid separated by C-18 reverse-phase column, and the photodiode array detector was used, simultaneously chromatogram were collected at 254nm, 280nm, 365nm. The content of folic acid was determined quickly by taking advantage of three wavelength peak area ratio. Results: The peak area of folic acid ranged from 0.1μg to 2.0μg has better linear relation with the sample size. The correlation coefficient was 0.9999, and the detection limit was 1.5mg/L. The rate of recovery was between 81.80% and 88.77%, and the average of recovery rate was 85.91%, relative standard deviation was 1.27%. Conclusions: The method is simple, accurate, reproducible and can be used to analyze folic acid quantitatively in fluid milk products.3. Study on the fortification technology and stability of fortified folic acidObjective: To study the addition form, additive quantity and addition process of folic acid added in liquid milk, and the stability of folic acid after addition. Methods: In order to choose the addition form, HPLC was applied to determine the content of the folic acid in dry and wet methods respectively. The additive amount was accordant with the intakes of folic acid in the Chinese Dietary Reference recommended for pregnant women, and the content of folic acid should not exceed the dose in "food nutrition fortifier use of health standards" about requirements of the amount. The best addition process of folic acid was determined by comparing the results of the folic acid before and after sterilization. The stability of folic acid was researched in 24d added in crude and fresh milk and the milk after sterilization bought in supermarket. Results: The wet addition form dissolved by 0.01mol/L NaHCO3 solution was better; the recovery ratio of folic acid was 99.6%. The additive amount of 2mg/L can essentially meet the intake demand for pregnant women. The recovery ratio of folic acid was 98.3% and 99.4% respectively pre-sterilization and post-sterilization. The effect of folic acid enhanced in crude and fresh milk was worse than that in the milk after sterilization, the post-sterilization loss ratio of folic acid was 31.6% after 24d. Conclusions: In this chapter, folic acid was dissolved by 0.01mol/L NaHCO3 and added after sterilization with 2mg/L. Folic acid fortified in milk had good stability over a storage period. The fortification method is simple and costs lowly and can be used for the production of folic acid enhanced liquid milk.