Effect of Milk Solids Concentration on the Quality and Yield of Labneh

摘要

Labneh is native and popular concentrated yoghurt largely produced and consumed in the Middle -East. In this study, the effect of different concentrations of milk solids on the quality and yield of Labneh was investigated. Accordingly, raw cows milk was first supplemented with a Skimmed Milk Powder to increase the Total Solids content. Milk samples obtained after fortification were then blended before their pasteurization at 85°C for 30 minutes. Different yoghurts were made by incubating various milk samples with 3% of a mixture of Lactobacillus bul-garicus and Streptococcus thermophilus (ratio 1:1) at 42 ±1°C for 4 h. Finally, each sample of yoghurt was collected in a cloth -bag and drained at 5°C for about12 hours (overnight). When fresh Labnehs were tested, results indicated that varying milk solids influenced remarkably the yield. In fact, the yield of Labneh increased with the increase in Total solids of Milk. The high moisture retained in Labneh also contributed to the observed high yield. On the contrary, as compared with the control, the treated products varied slightly in pH, and titratable acidity. Rheological and sensory analyses of the products showed that fortification of raw milk with Non -Fat Skim Milk Powder (NFSMP) for making Labneh resulted in an acceptable product. However, only Labneh corresponding to a Milk Solids concentration near to 15. 50% had a smooth texture, a continuous body, and a favorable spread-ability.