M. Bilek, E. Cebula, K. Krupa, K. Lorenc, T. Adamowicz, S. Sosnowski
Abstract. Three experiments were carried out to assess the effectiveness of the so-called new technologies in extending birch tree sap shelf life. In the first one, microfiltration of birch sap was carried out using 0.22 μm, 0.45 μm and 0.8 μm filters. In the second experiment, ultraviolet radiation was applied for 5, 15 and 45 minutes. In the third experiment ultrasound was applied with one-, two-, three- and four-fold use. Regardless of the pore diameter, all the microfiltered samples were nonperishable for at least a month at room temperature. The efficacy of ultrasound was also demonstrated. The fourfold use of ultrasound proved to be the most effective and prolonged the shelf life of birch sap from one to two days at room temperature and from four to twelve days in refrigeration conditions. In turn, the use of ultraviolet radiation did not extend the shelf life of birch sap, although in refrigeration conditions the clouding was significantly inhibited. However, there is no doubt that among the so-called new technologies, microfiltration is the most advantageous in extending shelf life of birch sap and has perspectives for use in food industry.
Keywords: birch tree sap, microfiltration, ultraviolet, ultrasound, shelf life, clean label