QUALITY ASSURANCE OF DIFFERENT TYPES OF YOGHURT IN KHARTOUM STATE MARKETS

Abstract

This study was carried out to insure the quality of different types of yoghurt sold at Khartoum State markets. The types of yoghurt used in this study were Capo, Daima , Kenana and Traditional yoghurt . chemical ,physical and microbial examinations were 4 conducted for the samples of these types ,also pH, titratable acidity were determined during ten days storage period . For Capo, Daima ,Kenana and Traditional yoghurt, the crude protein %was 4.10, 4.80, 4.50 and 4.00 ; the Ash content % was 0.60, 0.61 , 0.60 and 0.50, respectively. The fat content % was 2.50, 3.00 , 2.00 and 4.00 , while The Total solid % was 14.30 , 15.27, 13.30 and 13.90, respectively. The titratable acidity as lactic acid was 0.80%, 0.90% ,0.96% and 0.90% for Capo, Daima ,Kenana and Traditional yoghurt respectively . pH values for Capo, Daima, Kenana and Traditional yoghurt were 4.70, 4.65, 4.60 and 4.65, respectively . For the tested samples minerals content (mg /100g) as follows, Calcium content was from 680 to 663 ; the Phosphate content was from 90 to77 ; the Sodium content was from 80 to 73 ; the potassium content was from 123 to 103 ; the Ferric content was from 50 to 37 ; while the Magnesium content was from 13 to1.9 . The total amino acid content ( mg/100gm )was 2042.857, 1862.225, 2330.725 and 1883.1 for Capo, Daima ,Kenana and Traditional yoghurt, respectively. Total viable count of bacteria (cfu/ml) was 4.2×107 , 8.0×106 , 4.8×107 and 7.3×106 ; the total count of Lactobacillus was 2.40×106, 1.60×106, 9.8×106 and 8.7×105 for Capo, Daima ,Kenana and Traditional yoghurt, respectively . the total count of streptococcus was 6.0 ×106 , 9.6×105 , 7.2×105 and 3.2×104 for Capo, Daima ,Kenana and Traditional yoghurt, respectively . Traditional yoghurt recorded 43 cells total coliforms while the other samples obtained zero ,and all samples gave zero for E. coli count . For yeasts and moulds count the traditional yoghurt sample obtained 5.6×105 count as yeast while the other samples obtained negative results. During ten days storage for the samples a titratable acidity increased and it was in the range from 0.8 to 1.3 while the pH values decreased and it was the ranging from 4.3 to 4.7 5 According to the above mentioned results we can conclude that the most of tested samples conform with the International standards of yoghurt ,while the traditional yoghurt samples showed slight difference in the microbial number and this may be due to the use of unsterilized equipments . In general, the tested samples were rich in amino acids, minerals , proteins and of good microbial characteristics.