Effect of Addition of Malted Finger Millet Flour on Physical Properties of Yoghurt

Abstract

The effect of addition of malted finger millet flour (MFMF) on physical properties of stirred yoghurt was investigated. Stirred yogurts were prepared using commercial pasteurized and homogenized 3.25% fat milk by incorporating MFMF at the rate of 0% (Control), 1% (T l), 2% (T2), 3% (T3) and 4% (T4) levels after the heat treatment of the yoghurt mix at 85°C for 30 min followed by cooling to 60°C. Incubation of yoghurt mix was carried out at 42°C after inoculation of the mix by 2% (w/w) commercial yoghurt culture containing Streptococcus thermophilus and Lactobacillus delbruekii ssp. bulgaricus (1:1) until pH decreased to 4.6. Yoghurts were tested for susceptibility to whey syneresis, water holding capacity (WHC), viscosity and instrumental colour. Significant (p<0.05) increase of whey syneresis from 17.1+0,4 to 28.5±0.3%, significant (p<0.05) decrease of WHC from 74.9±0.4 to 62.4±0.7% and viscosity from 1.51+0.01 to 1.01±0.02 Pa. s were observed with increasing MFMF in the yoghurt from 0 to 4%. Addition of MFMF up to 4% did not significantly (p>0.05) change the L* (lightness) and a* (greenness) values of the yoghurt. However, b* (yellowness) value decreased significantly (p<0.05) with increasing MFMF. The results of the study revealed that the incorporation of increasing levels of MFMF decreased the consistency and physical stability of yoghurt, making it less acceptable to the consumers.