Liofilização como alternativa para conservação do leite humano

Resumo (EN)

Objective – The benefits of breastfeeding have being reported in the literature. The improvement of the accessibility conditions to this important food to all infants is a challenge for the professional nutritionist. Methods – Samples of human breast milk were collected from Taubaté city, São Paulo. They were submitted to lyophilization and frozen in liquid nitrogen at –210 ºC and they were remained in lyophilizer during 24 hours. After the lyophilization, the milk was analyzed and compared with in natura milk with respect to the following nutrients: lipids by direct extraction in Soxhlet apparatus, reducing carbohydrates by titration in lactose, protein by semi-micro Kjeldahl methodology,calcium by titration and immunoglobulins by agarose gel electrophoresis in order to visualize the gamma bands. Tests of reconstitution were also carried out by diluting 30 g of dried milk in 100 mL of filtered water. The analyses were performed in triplicate and then analyzed statistically. Results – The triplicates analyzed presented levels of lipids, lactose, protein and calcium unchanged in comparison with the values of non-lyophilisate samples as described in the literature. In the restitution tests, the color and the fluidity were similar to in natura milk and the dilution was total. The electrophoresis also showed the presence of the gamma bands, that suggests the conservation of the immunoglobulin. Conclusion – The results showed that lyophilization process is favorable, compared with other conservation processes, since that is not based in the heating as the main factor to reduce the water activity, but the physical state of matter: sublimation.