Vega-Gálvez Antonio, Ah-Hen Kong, Chacana Marcelo, Vergara Judith, Martínez-Monzó Javier, García-Segovia Purificación, Lemus-Mondaca Roberto, Di Scala Karina
Department of Food Engineering, Universidad de La Serena, Av. Raúl Bitrán s/n. 599, La Serena, Chile.
Instituto de Ciencia y Tecnología de los Alimentos, Universidad Austral de Chile, Julio Sarrazín s/n., Valdivia, Chile.
Food Chem. 2012 May 1;132(1):51-9. doi: 10.1016/j.foodchem.2011.10.029. Epub 2011 Oct 25.
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.
这项工作的目的是研究温度和风速对苹果（澳洲青苹品种）片干燥动力学及干燥过程中品质属性的影响。实验在40、60和80°C以及0.5、1.0和1.5m·s⁻¹的风速条件下进行。有效水分扩散率随温度和风速的增加而增大，在研究的最高温度和风速条件下达到15.30×10⁻⁹m²·s⁻¹。复水率随风速和温度的变化而改变，表明加工过程导致了组织损伤。色差ΔE在80°C时表现出最佳结果。在40°C和0.5m·s⁻¹条件下的DPPH自由基清除活性表现出最高的抗氧化活性，最接近新鲜样品。尽管ΔE随温度降低，但抗氧化活性几乎没有变化，甚至在高风速下有所增加，这表明褐变产物具有抗氧化能力。总酚含量随温度降低，但在高风速下观察到热降解的延缓。还使用玻璃化转变概念和微观结构分析对硬度进行了测定和解释。
