Impact of lactose content in milk on yoghurt characteristics during storage

Istražio se utjecaj različitih udjela laktoze (4,8, 7 i 10%) u mlijeku na karakteristike jogurta te se iz izmjerene kiselosti (°SH) odredila količina nastale mliječne kiseline. Enzimskom metodom su se analizirale promjene udjela laktoze u uzorcima mlijeka prije fermentacije te proizvedenim uzorcima jogurta nakon 1., 10. i 21. dana čuvanja u hladnjaku. Proizvedeni fermentirani proizvodi su dobiveni upotrebom inokuluma bakterija mliječne kiseline (Lactobacillus delbrueckii ssp. bulgaricus i Sreptococcus thermophilus). Uz viskoznost i senzorske karakteristike, ispitala se i mikrobiološka kvaliteta uzoraka jogurta tijekom 1. i 21. dana čuvanja pri temperaturi od 8°C.The aim was to investigate the effects of various lactose content (4,8, 7, and 10%) in milk on the characteristics of yoghurt and from the measured acidity (° SH) determine the amount of lactic acid. Enzymatic method was used to analyze the changes of the lactose in milk samples before fermentation and in produced samples of yoghurt after 1st, 10th and 21st day of storage in the refrigerator. Produced fermented products were made using inoculum of lactic acid bacteria (Lactobacillus delbrueckii ssp. Bulgaricus and Sreptococcus thermophilus). In addition to viscosity and sensory characteristics, the microbiological quality of yoghurt samples were examined during 1st and 21st day of storage at 8°C