title: Effect of temperature and air velocity on drying kinetics, antioxidant capacity, total phenolic content, colour, texture and microstructure of apple (var. Granny Smith) slices.
abstract: The aim of this work was to study the effect of temperature and air velocity on the drying kinetics and quality attributes of apple (var. Granny Smith) slices during drying. Experiments were conducted at 40, 60 and 80°C, as well as at air velocities of 0.5, 1.0 and 1.5ms(-1). Effective moisture diffusivity increased with temperature and air velocity, reaching a value of 15.30×10(-9)m(2)s(-1) at maximum temperature and air velocity under study. The rehydration ratio changed with varying both air velocity and temperature indicating tissue damage due to processing. The colour difference, ΔE, showed the best results at 80°C. The DPPH-radical scavenging activity at 40°C and 0.5ms(-1) showed the highest antioxidant activity, closest to that of the fresh sample. Although ΔE decreased with temperature, antioxidant activity barely varied and even increased at high air velocities, revealing an antioxidant capacity of the browning products. The total phenolics decreased with temperature, but at high air velocity retardation of thermal degradation was observed. Firmness was also determined and explained using glass transition concept and microstructure analysis.
authors.affiliation: Department of Food Engineering, Universidad de La Serena, Av. Raúl Bitrán s/n. 599, La Serena, Chile. Electronic address: avegag@gmail.com.
authors.forename: Antonio
authors.initials: A
authors.lastname: Vega-Gálvez
authors.affiliation: Instituto de Ciencia y Tecnología de los Alimentos, Universidad Austral de Chile, Julio Sarrazín s/n., Valdivia, Chile.
authors.forename: Kong
authors.initials: K
authors.lastname: Ah-Hen
authors.affiliation: Department of Food Engineering, Universidad de La Serena, Av. Raúl Bitrán s/n. 599, La Serena, Chile.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Chacana
authors.affiliation: Department of Food Engineering, Universidad de La Serena, Av. Raúl Bitrán s/n. 599, La Serena, Chile.
authors.forename: Judith
authors.initials: J
authors.lastname: Vergara
authors.affiliation: Department of Food Technology, Universidad Politécnica de Valencia, Camino de Vera s/n. 46022, Valencia, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Martínez-Monzó
authors.affiliation: Department of Food Technology, Universidad Politécnica de Valencia, Camino de Vera s/n. 46022, Valencia, Spain.
authors.forename: Purificación
authors.initials: P
authors.lastname: García-Segovia
authors.affiliation: Department of Food Engineering, Universidad de La Serena, Av. Raúl Bitrán s/n. 599, La Serena, Chile; Department of Mechanical Engineering, Universidad de Santiago de Chile, Av. Bdo. O'Higgins 3363, Santiago, Chile. Electronic address: rlemus@userena.cl.
authors.forename: Roberto
authors.initials: R
authors.lastname: Lemus-Mondaca
authors.affiliation: Food Engineering Research Group, Universidad Nacional de Mar del Plata, Juan Justo 4302, Mar del Plata, Argentina; CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas), Av. Rivadavia 1917, Mar del Plata, Argentina.
authors.forename: Karina
authors.initials: K
authors.lastname: Di Scala
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D003116:Color; D005503:Food Additives / Q000032:analysis; D005511:Food Handling / Q000379:methods*; D007700:Kinetics; D027845:Malus / Q000737:chemistry*; D010636:Phenols / Q000032:analysis*; D013696:Temperature
chemical_list: D000975:Antioxidants; D005503:Food Additives; D010636:Phenols
keywords: Antioxidant activity; Apple; Drying kinetics; Microstructure; Total phenolics