Abstract

Solar drying is a sustainable process that may impact the quality of dried food. This is because, pigments contained in food are sensitive to sunlight, and exposure to ultraviolet radiation can affect them. We applied biopolymer-based coatings on strawberry, from hydro-colloidal solutions of Opuntia ficus indica-mucilage, fenugreek, xanthan gum, gum Arabic, and guar gum to evaluate their potential use as UV filters for solar drying of food. Thermal properties and the optical transmittance, absorbance and reflectance of the coatings were measured to assess their influence on food-sunlight interaction. During the drying experiments, the moisture content, total anthocyanins (TA), and total phenolic compounds (TPC) were measured. Optical and thermal properties are influenced by the biopolymer-based coatings. Also, the optical properties are influenced by the coating thickness. The differences in optical and thermal properties influence the drying process. Differences exist in the drying rate for strawberry slices with coating, compared with those without the coatings. In general, the TA and TPC content in the product are better preserved under solar drying than in control experiments done in a drying oven. A partial transmittance of solar UV radiation is recommended to obtain increased TA and TPC contents in the dried product.

Details

Title
Optical and thermal properties of edible coatings for application in solar drying
Author
López-Ortiz, A 1 ; Pacheco Pineda I Y 2 ; Méndez-Lagunas, L L 3 ; Balbuena, Ortega A 1 ; Guerrero Martínez Laura 1 ; Pérez-Orozco, J P 2 ; del Río J A 1 ; Nair, P K 1 

 Universidad Nacional Autónoma de México, Instituto de Energías Renovables, Morelos, Mexico (GRID:grid.9486.3) (ISNI:0000 0001 2159 0001) 
 Tecnológico Nacional de México, Instituto Tecnológico de Zacatepec, Departamento de Ingeniería Química y Bioquímica, Morelos, Mexico (GRID:grid.484694.3) (ISNI:0000 0004 5988 7021) 
 Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional (CIIDIR), Instituto Politécnico Nacional, Oaxaca, Mexico (GRID:grid.418275.d) (ISNI:0000 0001 2165 8782) 
Publication year
2021
Publication date
2021
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2525888697
Copyright
© The Author(s) 2021. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.