Application of ultrafiltration technique for the quality improvement of dahi.

Ultrafiltered milk (UF1 and UF2), ultrafiltrate retentate added milk (UF3 and UF4) and SMP added milk (UF0) were used for dahi preparation in the present study. Treatments were evaluated for rheological, textural and sensorial characteristics. Significant increase (p < 0.01) in values of firmness, stickiness, work of shear, work of adhesion and sensory scores, but significant decrease (p < 0.01) in whey syneresis values were observed with treatments UF1, UF2, UF3 and UF4 as compared to UF0. Principal component analysis (PCA) revealed that first four principal components (PC) explained 87.39 % relationship between samples and attributes. PC1 accounted for 48.34 % of data variance was characterized by protein content, firmness, work of shear, body & texture and opposed by total carbohydrates, stickiness, syneresis and work of adhesion. Total carbohydrates content (r = -0.982, P < 0.01), whey syneresis (r = -0.783, P < 0.01), stickiness (r = -0.729, P < 0.01) and work of adhesion (r = -0.684, P < 0.01) are negatively while body and texture (r = +0.600, P < 0.01), firmness (r = +0.574, P < 0.05) and work of shear (r = +0.538, P < 0.05) of dahi are highly positively correlated with protein content.