EVALUATION OF BIRCH SAP (BETULA PENDULA) QUALITY DURING STORAGE

Abstract

This study presents the quality assessment of fresh and heat treated birch sap (Betula pendula) during 4 weeks of storage at 4 ºC. The entire quantity of birch sap was divided into three equal parts: a part was subjected to a pasteurization process, a part was subjected to a direct heat treatment at 60 °C and a part was kept fresh. The total microbial number of fresh collected birch sap was 94 CFU·mL-1 and after applying heat treatment the total microbial number decreased significantly (maximum 1 CFU·mL-1). For quality evaluation of birch sap samples during storage the element minerals content, pH, total acidity, conductivity, total microbial number, antioxidant capacity and polyphenols content were determined. The pasteurized birch sap presented a greater stability during storage than the other two samples, the pH varied slightly (3.47 - 3.16) and the sap conductivity showed a slight increase from 672.4 μS·cm-1 to 759 μS·cm-1 .

Keywords

• antioxidant activity
• birch sap
• minerals
• pca
• thermal treatment