Cider apple pomace as a source of nutrients: Evaluation of the polyphenolic profile, antioxidant and fiber properties after drying process at different temperatures

B Llavata; A Picinelli; S Simal; J A Cárcel

doi:10.1016/j.fochx.2022.100403

Cider apple pomace as a source of nutrients: Evaluation of the polyphenolic profile, antioxidant and fiber properties after drying process at different temperatures

Food Chem X. 2022 Jul 26:15:100403. doi: 10.1016/j.fochx.2022.100403. eCollection 2022 Oct 30.

Authors

B Llavata¹, A Picinelli², S Simal³, J A Cárcel¹

Affiliations

¹ Analysis and Simulation of Agro-food Processes Group, Food Technology Department, Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain.
² Area of Food Technology, SERIDA, 33300 Villaviciosa, Asturias, Spain.
³ Department of Chemistry, University of the Balearic Islands, Ctra. Valldemossa, km 7.5, 07122 Palma de Mallorca, Spain.

Abstract

Apple pomace, the by-product of the cider industry, contains a high content of antioxidant compounds and dietary fiber. Drying would allow its preservation for a later use. The aim of this study was to evaluate the effect of the drying temperature on the drying kinetics, antioxidant properties and the fiber characteristics. For this, drying experiments were performed at different temperatures (40-120 °C). The increase in temperature enhanced the drying rate, as was shown by the effective diffusivity and mass transfer coefficient identified by modelling. The influence of temperature was quantified through the activation energy (38.21 kJ/mol). Regarding the retention of antioxidant properties, the best results were found at 80-100 °C while 40-60 °C was the best temperature range for the fiber characteristics. Therefore, 80 °C could be an adequate temperature for drying of cider apple pomace, as it represents a good balance between kinetics, and antioxidant and fiber properties.

Keywords: S x y 2 , standard deviation of the estimation; S y , standard deviation of the experimental data; ρ s s , dry solid density (kg dm/m3); φ a i r , the relative humidity of the drying air; AA, ascorbic acid; AC, Antioxidant Capacity; AIR, Alcohol Insoluble Residue; Alcohol insoluble residue; Antioxidant properties; By-product; CAP, Cider Apple Pomace; D0, pre-exponential factor (m2/s); Deff, effective diffusivity (m2/s); Drying kinetics; Ea, activation energy (kJ/mol); FRAP, Ferric Reducing Ability Power; Fiber properties; L, the thickness of the CAP layer (m); ORC, Oil Retention Capacity; PPO, Polyphenoloxidase; R, ideal gas constant (kJ/mol K); SC, Swelling Capacity; T, drying time (s); T, temperature of each experiment (K); TPC, Total Phenolic Content (TPC); VC, Vitamin C; Var, percentage of explained variance; W, moisture content (kg water/kg dried matter); WRC, Water Retention Capacity; aw, water activity; dm, dried matter; k, mass transfer coefficient (kg water/m2s); x, direction of the water transport (m); Δ/Δ, drying rate.