Effects of Microbiological and Physicochemical Properties of Cow’s Milk and Goat’s Milk Dadih Inoculated with Various Lactobacillus Species

Abstract

Dadih is a dairy-based product and it is one of the most popular desserts among Malaysians and Indonesians. It is made from raw milk which naturally contains various types of microorganisms. This study was conducted to develop cultured dadih by inoculating various Lactobacillus species such as Lactobacillus acidophilus, Lactobacillus plantarum and Lactobacillus paracasei into dadih made from cow’s milk and goat’s milk. Prior to isolation of LAB from control dadih (dadih without inoculation with LAB), the dadih was stored at 4˚C for 48 hours. The microbiological (general microbial load, viability of and LAB, mould and yeast count) and physicochemical properties (pH, lactic acid content, total soluble solid, colour, texture and proximate composition) of dadih with different LAB strains and without LAB strain were determined. Results showed that L. paracasei spp. paracasei, Lactobacillus brevis, Lactobacillus casei were isolated from cow’s milk dadih while only L. paracasei spp. paracasei was isolated from goat’s milk dadih. The number of LAB ranged from 5.73 to 6.06 log10 CFU/g for cow’s milk dadih and 5.19 to 5.88 log10 CFU/g for goat’s milk dadih. Results revealed that dadih inoculated with LAB has lower pH and greater amount of lactic acid produced than control dadih. Total soluble solid for dadih with LAB also decreased. Hardness of dadih without LAB culture was higher compared to the inoculated dadih with LAB cultures. Proximate compositions (moisture, ash, crude fat, crude protein and total carbohydrate) showed variations due to differential formulations and incorporations of different LAB strains. Findings showed that L. acidophilus was chosen as the best starter culture for both types of dadih because it has significant effects on pH, titratable acidity, total soluble solid and texture of the dadih.