Optimization of chipotle pepper smoking process using response surface methodology

Effects of smoking time and temperature on optimal chipotle pepper production were evaluated and optimized using the response surface methodology. Batches of red jalapeño peppers were smoked under different temperatures (65.8, 70, 80, 90, 94.1C) and times (0.96, 2, 4.5, 7, 8 h). Afterward, samples were evaluated for moisture, rheological properties and total phenols. Samples were then dried from 80C to between 0.123 and 0.204 kg H2O/kg dry matter and evaluated for rheological properties, texture, rehydration, color and phenols. Phenol content, rehydration ratio, firmness of peppers, and rheological properties and color of puree were affected (P < 0.05) by both temperature and time. Best smoking conditions used temperatures of 74–79C, and times between 8.0 and 7.4 h resulting in viscosities of 5.1–6.5 Pa·s with phenol content of 110–120 mg/kg, rehydration ratios of 3.7–4.1, firmness of 1.27–1.49 N and acceptable color. Smoking time was significantly reduced and quality maintained. PRACTICAL APPLICATIONS: Chipotle pepper is highly appreciated by consumers because of their aroma and flavor characteristics. Chipotle pepper is obtained by smoking red jalapeño in open ovens, where combustion gases from hardwoods are passed during long times to smoke and dehydrate them. This process has the disadvantage of producing environmental contamination and wide quality variability because of a poor process control. In this study, a correlation of smoking and drying was optimized in order to determine the effect of temperature and smoking time on the physical and chemical characteristics of the chipotle pepper. Additionally, polynomial models are presented for each variable evaluated in the smoking chipotle pepper operation and optimized for the desired quality of the chipotle pepper. This information can be useful to processors because they can achieve a ninefold reduction in the smoking time compared with the traditional smoking processes without affecting the chemical and physical characteristics of chipotle peppers.