Effect of Adding Different Levels of Gum-Arabic on Physicochemical, Microbiological and Sensory Characteristics of Sudanese White Cheese during Storage

Abstract

This study was carried out at the laboratory of Dairy Science and Technology Department, College of Animal Production Science and Technology at Sudan University of Science and Technology during the period from September 2014 to January 2015, to determine the effect of different levels of Gum Arabic on the physicochemical characteristics, microbiology quality and sensory properties during storage. Three hundred and fifty liters (350 liters) of standardized milk were used for the production of Sudanese white cheese with different levels of Gum Arabic (0.5, 0.75%). Seven treatments were carried out as follows: first treatment is the control in which cheese milk had no additive (3% of fat). In the second and third treatments with 3% of fat, fourth and fifth treatments with 25% of fat and sixth and seventh treatments with 2% of fat for each of the above treatments 0.5 and 0.75% of Gum Arabic were added respectively, to cheese milk before pasteurization (at 72oC) for one minute and then manufactured into a Sudanese white cheese and stored at refrigerator (4oC) for 120 days and examined for the physicochemical, microbiological and organoleptic quality at day 0, 30, 60, 90 and 120 intervals. The results indicated that total solids, fat, volatile fatty acids and ash content increased significantly (P<0.05) with increase levels of Gum Arabic, while protein and pH decreased significantly (P<0.05) with the levels of Gum Arabic. There were significant effect (P<0.05) of the levels of Gum Arabic on total bacterial count, coliforms bacterial count, lactic acid bacterial count and yeasts and moulds counts. The total bacterial count, coliforms and yeasts and moulds decreased with the levels of Gum Arabic, while lactic acid bacteria increased. The organoleptic of the cheese revealed that there were significant effect (P<0.05) of Gum Arabic on colour, flavour and texture, while there were no significant effect on saltiness, the results also indicated that there were significant effect (P<0.05) of the storage period on total solids, protein, ash, pH, volatile fatty acids and ash content. Crude protein, ash and total solids content increased with storage period, while pH, volatile fatty acids and fat increased with the storage period in all treatments. The total bacterial counts decreased significantly (P<0.05) with storage period from day zero up to day 90 and then slightly increased. Coliforms increased from day zero up to day 90 of the storage and did not detected at day 120, lactic acid bacteria decreased from day zero up to day 60 then increased at day 90 thereafter wards decreased at day 120, while yeasts and moulds increased at day 30 of the storage time then afterwards decreased up to day 90 and completely disappeared at day 120 of the storage time. Flavour, texture and saltiness decreased significantly (P<0.05) with the storage period, while colour increased significantly (P<0.05) at day 60 and then gradually decreased up to day 120 of the storage period. The best scores for colour were recorded at day 60, while the best flavour recorded at day zero. Saltiness increased at day zero and then decreased afterwards up to the end of storage period. The present study concluded that significant effect was found on the physicochemical, microbiological and sensory characteristics of the Sudanese white cheese during the storage as the result of using Gum Arabic.