The agricultural industry generates large amounts of residues, commonly considered waste. In this study, we used by-products from industrial processing of cacao, coffee and orange. An enriched dairy product was elaborated using a 10% aqueous extract of cocoa bean shells, coffee husk and orange peel. A design of mixtures of extreme vertices was applied to test variation in the proportion of the three ingredients in the aqueous extract. Sensorial characteristics like taste, odor, color and appearance were evaluated by a semi-trained testing panel applying the method of multiple comparisons, comparing the test formulations with a commercial drink of coffee and cocoa. The test formulations that were rated similar to the reference drink were selected to improve their total polyphenol content (TPC) applying a mathematical process of linear optimization. This approach indicated an optimal formulation containing 74 % cocoa bean shells, 24.50% coffee husk and 1.50% orange peel. This formulation gave TPC values of 5.74 ± 0.41 Gallic Acid Equivalent (GAE) mg/g, 82.20 ± 0.08% antioxidant activity by the diphenylpicrylhydrazyl (DPPH) assay and 114.78 mg/l caffeine content. The results demonstrate the feasibility to produce a drink enriched in antioxidant compounds retaining good sensorial attributes using industrial sub products.
Key words: drink, polyphenols, dpph, mixture design
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