pH value is considered as an important factor in the field of meat quality because of it's influence on many characteristics including shelf life,color, water holding capacity and texture of meat and meat products
Data presented in Table (2), showed that pH values in fresh sausage samples which treated with or without tomato peel ranged from 5.10to5.61mg / 100g sample. The normal pH of meat products range from 4.8-6.8 while that of fresh sausage has been suggested to be at a pH of not less than 5.5 [28, 29]. On the other hand, there were significant difference (p 0.05) in pH values among all raw sausage samples. A decrease in the pH value of meat products containing tomato paste have been reported by Candogan [9] and Deda et al. [2]. The decrease could be due to the high concentrations 10- 15% of tomato product added by these authors,whereas we added 3-6%of dry tomato peel. The G sample had the highest pH value (5.61) followed by each of the H sample (5.57) and D sample (5.50) with no significant differences between them. During freezing at-18°C, pH values of all raw sausage samples whether the control or other samples was decreased as the period of storage lengthened. These results are in accordance with those obtained by Moawad et al. [30]. By the advancement of frozen storage, the highest decrease in pH value was observed in the C sample at a long of storage followed by F and I sample. So that pH values of the samples was decreased along with the decreased level of tomato peel and nitrite.