Aim: The aims of this study are to characterize the nutrient compositions and protein profiles of Etawah breed (PE) goat yogurt fermented by double cultures .
Material and Methods: To accomplish this, we used goat and bovine milk in five treatment groups: (1) fresh milk bovine, (2) goat,(3) milk fermented by L. acidophilus and S. thermophilus (LA + ST), (4) L. bulgaricus and S. thermophilus (LB+ ST),and (5) a comersial mixture. PE goat milk was fermented using 2.5% starting bacterial concentrations at 45oC with a pH ranging from 4.5 to 6.6. Nutrient compositions were measured by proximate analysis.SDS PAGE was conducted using 15% separating and 3% stacking gels. To measure the density of protein bands, we used QuantityOne software.
Results: Our results indicated that LA+ST and LB+ST treatments had higher levels of lipids than the control treatment. Conversely, both strain combinations had lower levels of proteins than the control. Organoleptic testing suggests that many attributes (e.g., colour, taste, smell, texture and viscosity) differ significantly from the control. Protein profiles revealed that while the LB + ST and commercial cultures contained proteins with a molecular weight of 36 kDa, the LA + ST cultures did not appear to possess this protein.Based on the molecular weight, we suggest that this protein is in the alpha casein group.
Conclusion: The protein composition of fermented goat and bovine milk is similiar, but the absence of band with molecular weight 36 kDa from goat milk, LB+ST and mix comercial.
Casein Protein, Goat Milk, L. bulgaricus L. acidophillus S. thermophillus