Application of Response Surface Methodology to Optimize Roasting Conditions in Cocoa Beans Subjected to Superheated Steam Treatments in Relevance to Antioxidant Compounds and Activities

Abstract

Roasting is an essential technological process used to produce high-quality cocoa-based products. Response surface methodology (RSM) was employed to optimize the roasting conditions in cocoa beans based on antioxidant compounds (total phenolic, total flavonoids) and their activity (percentage inhibition of 1,1-diphenyl-2-picrylhydrazyl [DPPH] radical and ferric-reducing antioxidant power assay) using two variables: temperature and time. Cocoa beans were roasted at temperature ranging between 150 and 250°C for 10–50 min using superheated steam. The effects of the roasting conditions on the antioxidant properties of cocoa beans were investigated using a second-order central composite design. Results showed that roasting temperature and time significantly affect antioxidants in cocoa beans. Numerical optimization and superimposed contour plots suggested the optimal roasting conditions to be 192°C for temperature with 10 min of roasting time (R ² = 0.99). These conditions can be used for roasting of cocoa beans to produce high-quality cocoa products in terms of antioxidant properties.

Keywords:

• Antioxidant properties
• Cocoa beans
• Response surface methodology
• Roasting
• Superheated steam

ACKNOWLEDGMENT

The authors gratefully acknowledge the Cocoa Research and Development Center, Perak, Malaysian Cocoa Board, Malaysia, for supplying cocoa beans. Suggestions provided by anonymous referees are gratefully acknowledged.

Notes

*Statistically significant at p < 0.05.

**Statistically significant at p < 0.01.

*Statistically significant at p < 0.05.

**Statistically significant at p < 0.01.

*Statistically significant at p < 0.05.

**Statistically significant at p < 0.01.