Avaliação da eficácia do uso da técnica de liofilização no processo de conservação do leite humano

Abstract

Human milk, through the peculiarities of its nutritional composition is undoubtedly the most suitable to overcome such shortcomings food, allowing the newborn optimum adaptation to their new environment. Lyophilization is an operation of removing water by sublimation of ice. The use of lyophilization technology dehydration by cold (freeze dry) is a reliable method of preservation of biological products, being free from preservatives or chemicals. The objectives of this study were to evaluate the effects of freeze drying on the nutritional aspects and as an alternative conservation of human milk, as well as evaluating the package which best preserves this freeze dried food. For lyophilization, samples of 600 mL of colostrum and mature milk pasteurized 600mL were collected in the Human Milk Bank Fezinha Anzoategui of Woman Institute Dona Lindu, Manaus/AM. We determined the contents of lipids, proteins, carbohydrates, moisture and ash, besides the determination of vitamin A and proves reconstitution. The research protocol includes three storage conditions: time 0, three months in plastic wrap and foil pouch for three months under refrigeration. Analyses were performed in triplicate and then analyzed statistically. The average of the levels of lipid and protein were lyophilized colostrum of 1.64 g / dl and 1.70 g / dl, respectively. It was observed that protein content of mature milk lyophilized (1.59 g / dL) was still higher than the values previously observed in other studies. The average percentage of carbohydrate in the mature milk lyophilized (7.84 g / dL) is also in agreement with the literature. In comparing the types of packaging, there were no significant differences in moisture, lipid, carbohydrate and ash lyophilized colostrum stored for three months in a metal or plastic container. However, the protein content showed significant difference, suggesting that the metal packaging is a better option in the conservation of lyophilized colostrum for the preservation of this nutrient. In comparing the types of packaging, there were no significant differences in moisture, protein, carbohydrate and ash lyophilized mature milk stored for three months in a metal or plastic container. However, the lipid content significantly different, suggesting that the metal packaging is a better option in the conservation of the lyophilized mature milk in relation to the preservation of this nutrient. The concentration of vitamin A found in the colostrum before and after lyophilization were 1.21μmol/L and 1.16μmol/L, respectively. Regarding mature milk, the levels of 1.18μmol/L before lyophilization and 1.14μmol/L were found after processing. The loss of vitamin A during processing is probably the result of exposure to light bottles during thawing and re-bottling. The procedure used for reconstitution could be seen that the color was similar to non-lyophilized milk, fluidity remained stable, similar to the non-lyophilized milk and dilution was full, without formation of precipitates. The freeze-drying technique was favorable for preservation of human milk as it preserved the nutrients in human milk. It is suggested that the canister is the best alternative for the conservation of lyophilized human milk.