Optimization of functional spicy red pepper paste (Awaze) formulated from red pepper, garlic, red onion and ginger using optimal mixture design techniques

Abstract

Spicy red pepper paste, locally known as Awaze, is a traditional popular spicy paste consumed in Ethiopia. The objective of this research was to determine the optimum proportion of red pepper, garlic, red onion and ginger in the preparation of Awaze paste. Mixture design was used to establish the appropriate proportion of red pepper, garlic, red onion and ginger. A D-optimal mixture experimental design with 15 runs was generated by design expert software within the constraint: 60–90% red pepper, 10–30% garlic, 5–20% red onion and 5–10% ginger. The physicochemical, mineral content and texture profile of Awaze paste were determined. Significant differences (p < 0.05) existed in color, ash, fiber content, viscosity, antioxidant activity, mineral and texture profile. Linear model for ash content, quadratic model for a* and antioxidant activity, special cubic model for fiber content significantly (p < 0.05) explained the effect of the components on the physicochemical quality of Awaze paste with high predicted R-squared (R2) value. The optimum formula of Awaze paste was a mixture containing 65.66% red pepper, 10% garlic, 19.086% red onion and 5.254% ginger. The optimum formula exhibited an antioxidant activity of 44.64%, ash content of 7.56%, color (a* value) of 18.3 and fiber content of 27.5%. There was a significant difference between Awaze paste produced from optimum formula and control (Household made Awaze).The study indicated that antioxidant activity, color value(a*), viscosity, ash content, fiber content and chewiness of Awaze paste are directly related to the proportion of red pepper, garlic, red onion and ginger.