Effects of some storage contidions and additives on quality and stability of Sucuk (Turkish dry-fermented sausage)

ABSTRACT EFFECTS OF SOME STORAGE CONDITIONS AND ADDITIVES ON QUALITY AND STABILITY OF SUCUK (TURKISH DRY-FERMENTED SAUSAGE) Bozkurt, Hüseyin Ph. D. in Food Engineering Supervisor: Assoc. Prof. Dr. Osman ERKMEN December 2002, 219 pages In this work, aerobic plate counts (APC), mold and yeast counts and lactic acid bacteria (LAB) counts; pH values, 2-thiobarbituric acid (TBA) values, nitrosomyoglobin conversion rate, residual nitrite level and biogenic amine formations; and overall sensory quality were monitored for microbial, chemical and organoleptic changes in sucuk (Turkish dry-fermented sausage) during the ripening and storage periods (20, 30 and 40°C with 50, 65 and 80 % RH). These analyses were also determined in sucuks collected from local markets (firm-made) and butchers (traditional). APC and LAB increased (P<0.05) during the first 10 days of ripening and decreased (P<0.05) during the further ripening and storage periods. Starter culture had no effect (P>0.05) on the reduction of APC. Additives (nitrite, nitrate, a- tocopheroL ascorbic acid, potassium sorbate, potassium pyrophosphate, di-potassium hydrogen phosphate) had significant effect on the reduction of APC, LAB, and mold and yeasts counts. Increasing the storage temperature and % RH increased APC and LAB count significantly (P<0.05). pH values of sucuks were sharply decreased (P<0.05) during the ripening. Additives and starter culture decreased TBA values but increased pH values and nitrosomyoglobin conversion rate. Increasing % RH of storage room increased the TBA and nitrosomyoglobin conversions values but not pH values. The residual nitrite level sharply decreased (P<0.05) in sucuks made with nitrate/nitrite during thefirst five days of ripening periods. The amount of residual nitrite was low (P<0.05) in sucuks stored at 30°C. Histamine ranged from 0.00 to 292.66 mg/kg during the ripening and storage periods. Starter culture and additives limited (P<0.05) the histamine, tyramine and putrescine formation. Histamine formation was highest (P<0.05) at high RH (80 %) storage. The lowest (P<0.05) tyramine, Mstamine and putrescine concentrations were observed in sucuk type B9. Putrescine concentration changed inversely related with the pH values of sucuks. Its formation decreased (P<0.05) with addition of additives and starter culture into sucuks. It was found that additives had no effect (P>0.05) on the tryptamine and polyamines (spermidine and spermine) formation. It was observed that 1,7-diamino heptane, serotonin, spermidine and spermine concentrations were changed between 0.00-43.54, 0.00-57.26, 0.00-30.60 and 0.00- 3 1.29 mg/kg, respectively, in sucuks during the ripening and storage periods. Overall sensory quality increased during the first days of ripening. The lowest overall sensory quality was observed in sucuk type Al. Starter culture and additives increased (P<0.05) overall sensory quality. Nitrite/nitrate played important role in the formation of desired color (nitrosomyoglobin) and flavor; ascorbic acid, and o> tocopherol reduced the lipid oxidation; and phosphates improved textural properties of sucuks. Empirical equations were used to predict the chemical, microbial and overall sensory qualities of sucuks during the storage periods. It was found that empirical equations were well fitted to the experimental data. Traditional sucuks had higher APC, and mold and yeasts counts than that of firm-made sucuks. pH values and residual nitrite level of firm-made sucuks were higher (P<0.05) than that of traditional sucuks. Traditional sucuks were spicier and the dominant aroma was from spices. Generally, firm-made sucuks had no desired aroma. Key Words: Sucuks, stability, quality, safety, biogenic amine, TBA value, residual nitrite level u