Research On Milk Powder For Pregnant Women And Quality Maintenance Technology

At present,with better living conditions,the health of newborn babies and the nutritional status of pregnant women during pregnancy are particularly important.During pregnancy,there is an increased need for many macronutrients to maintain maternal homeostasis and support fetal growth for pregnant women.This article was combined with the special physiological characteristics of the pregnant woman and the requirements for various,nutrients in the early,middle and late stages.So the milk powder for pregnant women in different periods was designed to adjust and supplement their daily dietary nutrition.At the same time,the influence of application characteristics such as particle size,stability,total number of colonies,bulk density,tap density,fluidity and cohesion on the quality of milk powder was explored,and the production process was further optimized,and the quality maintenance of pregnant women’s milk powder during storage was analyzed.According to the nutritional needs of each period of gestation and the dietary reference intake of Chinese residents,the contents of various nutrients needed in early,middle and late pregnancy were designed to make different formula of milk powder.Fat globosphere membrane(MFGM),docosahexaenoic acid(DHA)and lactoferrin(Lf)were selected as functional components in the mid-pregnancy formula.Lactobacillus fermentum(CECT5716)which is from breast milk,and inulin were added to the third trimester formula as probiotics and prebiotics respectively.The optimal process parameters(homogenization pressure,sterilization temperature and spray temperature)of milk powder are determined by some application characteristics of milk powder.According to the analysis,Volumetric mean particle size(D[4,3])of the powder base liquid is at least 0.485,0.600 and 0.418 μm respectively.Its droplet distribution is relatively uniform and its size is uniform,and the base liquid has the best stability.When the sterilization temperature is 72℃ 15 s,the total number of microorganisms is higher than 85°C 20 s and 95°C 30 s.When the sterilization temperature is 95 ℃ 30 s,it has the worst color.While under the sterilization conditions: 85 ℃ 20 s,the three milk powders have the smallest particle size.Bulk density and tap density are important technical means for evaluating powder flow properties.The milk powder for pregnant women in different periods shows an upward trend with the increase of powder spraying temperature in bulk density and tap density.When the temperature is 175°C,the cohesion and fluidity of milk powder are the best.The changes in the quality of milk powder during storage were studied.The results showed crystals of the first and second milk powder appeared at 90 d and 180 d with the xrd image of lactose powder as the control.It is combined with the scanning electron microscope images.In the third milk powder,crystals appeared at 30 d,60 d,90 d and 180 d during storage.With the increase of time,the degree of fat oxidation and Maillard reaction of milk powder gradually deepened,and the degree of oxidation and browning of third milk powder for pregnant women was greater than that of first milk powder and second milk powder.The abundance of volatile substances detected in pregnant women’s milk powder is decreasing,and the reconstitution is worse.The relative abundance of Lactobacillus fermentum(CECT 5716)also showed a downward trend,and the detected content was 4.17×107 cfu/g at 180 d.At the same time,the quality of milk powder is also affected by the environmental humidity.There is a positive correlation between environmental humidity and total oxidation value and 5-hydroxymethylfurfural(5-HMF)content,and the milk powder with high relative humidity is more likely to find crystals.In addition,it was found through research that time and humidity had no significant effect on the activity of lactoferrin,but had a certain effect on the color of milk powder.