Micellar Casein and Whey Protein as EncapsulatingAgents of Natural Extracts: Antioxidant Capacity andPhenolic Compounds

Júlia d’A. Francisquini a, Elisângela R. Gomes b, Oscar A. Vega-Castro c, José C. Calderon d, Edwin Arcila d, Fabiano F. Costa,a Mirian P. Rodarte a, Ana Flávia Cerqueira a, Luiz Fernando C. De Oliveira e, Rodrigo Stephani e, Antônio F. De Carvalho b, Ítalo T. Perrone a.

a Federal University of Juiz de Fora, Faculty of Pharmacy, Zip Code 36036‑900, Juiz de Fora-MG, Brazil

b Federal University of Viçosa, Department of Food Technology, Zip Code 36570-900, Viçosa-MG, Brazil

c University of Antioquia, Carmen de Viboral Campus-Research Group Tendencias. And Department of Industrial Engineering, American University Corporation, Medellin-Antioquia, Colômbia

d University of Antioquia, Faculty of Pharmaceutical and Food Sciences, BIOALI Research Group, Cl. 67 #53‑108 Bloque 2-105, Medellín-Antioquia, Colômbia

e Federal University of Juiz De Fora, Department of Chemistry, Zip Code 36036-900, Juiz De Fora-MG, Brazil

Abstract:

Dairy proteins can be used as encapsulating agents for natural compounds during spray drying. This enhances the health benefits of both ingredients. This study aimed to determine the best encapsulating agent for three different natural extracts, considering their trolox equivalent antioxidant capacity (TEAC) and phenolic contents. The experimental strategy was based on three different natural extracts (passion fruit, avocado seed, and green coffee) encapsulated in two types of proteins (whey protein [WPC] and micellar casein [MC]). The particle size, morphology, Raman spectroscopy, TEAC, phenolic compounds, moisture, and water activity were measured during the experiment. The results indicated that only the green coffee extract modified the spectra of WPC and MC in the dry powders, which could be attributed to chlorogenic acid. MC promoted greater retention of phenolic compounds (226.30 mg GAE/100 g for passion fruit; 245.20 mg GAE/100 g for avocado seed; 331.05 mg GAE/100 g for green coffee in) and trolox equivalent antioxidant capacity (28.03 μmol TE/g for passion fruit; 27.29 μmol TE/g for avocadoseed; 13.31 μmol TE/g for green coffee) compared to those of WPC. Passion fruit and avocado seed extracts encapsulated in MC showed the highest trolox equivalent antioxidant capacity. In conclusion, the encapsulating agent exerted different effects on the encapsulation of natural extracts, depending on the TEAC and phenolic content.

Keywords: Spray drying; milk proteins; natural extracts; particle size; morphology; Raman spectroscopy.

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