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Alginate Encapsulation as a Preservation Method of Pitaya Fruit Juice (Stenocereus spp.)



Author(s)

Juan Antonio Rodríguez-Sánchez¹, María Isabel Cuatzo-Lozano², María Guadalupe Pérez-Loredo¹, Diana Imelda Abarca-Sarro¹ and Yoja Gallardo Navarro²

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DOI:10.17265/2159-5828/2017.03.002

1. Department of Environmental Systems Engineering, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional. Wilfrido Massieu s/n Ave., Unidad Profesional Adolfo López Mateos, Mexico City 07738, Mexico
2. Department of Biochemical Engineering, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional. Wilfrido Massieu s/n Ave., Unidad Profesional Adolfo López Mateos, Mexico City 07738, Mexico

Alginate is a widely used polymer matrix in food industry since it allows formation of spherical, soft, and strong membranes adequate for encapsulation of a large amount of products, including food. The flow rate of alginate solutions and the permeability of the capsules were evaluated within an acidic-low acidic pH range and different alginate concentrations. In solutions adjusted at different pH (3.0 to 7.0) with concentrations of alginate of 0.8, 1.0, and 1.2% w/v, flow rates at 20 °C were 6.95 to 10.00, 4.54-5.35, and 2.60-2.80 mL s^-1, respectively. Permeability of the capsules was evaluated in terms of the diffusion of H⁺ions (expressed as pH) and soluble solids (°Brix). Meanwhile both diffusions were minor at 4.0 < pH < 7.0 and were significantly superior at more acidic pH (P < 0.05), alginate concentration did not present significant effect. Yellow, purple, and red juices from Stenocereus spp. fruits (pitayas) were encapsulated using 1.0% of alginate and stored with isotonic solution (3 mL g^-1) at 4 °C in the dark. The capsules were spherical with diameter between 4.59 and 470 mm, weight from 82.60 to 97.50 mg, and volume of 0.075-0.098 mL. Pigment (total betalains content) diffusion reached equilibrium at 24 h of storage, at which point retentions of total betalains in the yellow, purple, and red capsules were 87.79, 96.13, and 85.13%, respectively. Also, changes in the color of the capsules were observed during storage.

Stenocereus, pitaya, betalains, alginate encapsulation, color stability.