Effect of cinnamon and nutmeg essential oils on the smoked meat (Se'i Sapi) quality

Se’i sapi is a traditional Indonesian smoked meat product that is normally degraded by both microorganisms and lipid oxidation. The aim of this study was to determine the effect of essential oils on the quality of sterilized se’i sapi. Firstly, antioxidant activity and total phenolic compounds of cinnamon (CEO) and nutmeg (NEO) essential oils, and liquid smoke were investigated. It was found that CEO and NEO had good potential on their antioxidant activities, while liquid smoke exhibited very low antioxidant activity. Total phenolic content of CEO and NEO showed a high value, which were 110.64 and 109.13 mg GAE/g, respectively. To produce se’i sapi, various concentrations (500, 750 and 1000 ppm) of each essential oil were added to the smoked meat formulation, then the meats were passed through the sterilization process. It was shown that various concentrations of each essential oil did not affect pH, moisture content, water holding capacity [WHC], color, and texture of the smoked meat samples. However, smoked meat samples containing both essential oils at 750 ppm were found to be the most liking score by 7-point hedonic sensorial test. Thus, the CEO or NEO at a concentration of 750 ppm were chosen for the storage study. The smoked meats were then stored at 30°C for 60 days, and were analyzed for physicochemical properties (pH, moisture content, WHC, color, texture, and lipid oxidation (thiobarbituric acid [TBA] value) and sensorial properties. The result indicated that CEO and NEO treated samples exhibited lower lipid oxidation, 0.37 and 0.36 mg MDA/kg, respectively, higher in WHC, 94.43 and 94.14%, respectively, higher in moisture content, 57.14 and 58.37%, respectively, and higher in lighteness value (L*), 47.63 and 46.14, respectively compared to the control (smoked meat without essential oil addition) at the end of storage time. In addition, malonaldehyde value of control, CEO and NEO treated samples increased during storage, but CEO and NEO treated samples had lower value than the control. Meanwhile, other properties (pH, moisture, WHC, color, and texture) decreased during storage, but CEO and NEO treated samples exhibited higher values in pH, moisture content, WHC, color, and texture than the control samples. The results from sensory analysis indicated that the addition of CEO and NEO showed no significant difference (p>0.05) on sour taste, rancid aroma, smoky aroma, juiciness, hardness and cinnamon or nutmeg aroma of the samples during storage, but found to be different (p≤0.05) in color at the later days of storage. Furthermore, the score of color, rancid aroma, smoky aroma, nutmeg and cinnamon aroma of all samples experienced a significant decrease during storage. While, juiciness and hardness score of CEO and NEO treated samples exhibited no significant decrease (p>0.05) during storage. In term of shelf life, the determination of TBA values at three different temperatures was used to calculate using Arrhenius model. It was found that based on TBA value, the expected shelf-life of sterilized se’i sapi would be 428, 1049 and 1097 days, for control, cinnamon and nutmeg essential oil treated samples, respectively.