The impact of solar convective drying on kinetics, bioactive compounds and microstructure of stevia leaves

被引：38

作者：

Hidar, Nadia ^{[1
]}

Ouhammou, Mourad ^{[1
]}

Mghazli, Safa ^{[1
]}

Idlimam, Ali ^{[2
]}

Hajjaj, Abdessamad ^{[3
]}

Bouchdoug, Mohamed ^{[4
]}

Jaouad, Abderrahim ^{[1
]}

Mahrouz, Mostafa ^{[1
]}

机构：

[1] Cadi Ayyad Univ, Dept Chem, LICVEDD ERIDDECV Lab Innovat & Sustainable Dev &, Marrakech, Morocco

[2] Cadi Ayyad Univ, Teachers Training Coll, LESPAM Lab Solar Energy & Med Plants, BP 2400, Marrakech, Morocco

[3] Cadi Ayyad Univ, CNEREE Natl Ctr Studies & Res Water & Energy, PB 511, Marrakech 40000, Morocco

[4] Cadi Ayyad Univ, Fac Sci Semlalia, Dept Chem, REMATOP Res Lab Mat React & Proc Optimizat, PB 2390, Marrakech, Morocco

来源：

RENEWABLE ENERGY | 2020年 / 161卷

关键词：

Polyphenol content; Stevia leaves; Solar convective drying; Quality; SEM analysis; Activation energy; THERMOPHYSICAL CHARACTERIZATION; ANTIOXIDANT CAPACITY; REBAUDIANA BERTONI; ENERGY; PERFORMANCE; DRYER; COLOR;

D O I：

10.1016/j.renene.2020.07.124

中图分类号：

X [环境科学、安全科学];

学科分类号：

08 ; 0830 ;

摘要：

Stevia is a natural non-caloric substitute to conventional sugar. The objective of this study was to investigate the effect of solar convective drying on kinetics and quality attributes of stevia leaves grown in Morocco. The evaluated drying temperatures were 50, 60, 70 and 80 degrees C with an air flow of 300 and 150 m(3)/h. Effective moisture diffusivity was in the range of 5.07 x 10(-11) and 3.14 x 10(-10) m(2) s-(1). An activation energy was found to be 37.81 kJ/mol. Additionally, effective moisture diffusivity increases with the increase in drying air temperature and air flow. The experimental results demonstrated the technical feasibility for the solar drying of stevia. However, drying process, affected quality characteristics of stevia leaves. From the results obtained it was verified that drying conditions, particularly temperature and air flow, lead to stevia modifications that can cause quality degradation. Chlorophyll contents as well as the total phenolic and flavonoids content decreased as both air-drying temperature and air flow increased. Additionally, at high temperature (i.e. 80 degrees C) and air flow, microstructural deformation happens when it is mainly driven by the high diffusion and evaporation rates of water. (C) 2020 Elsevier Ltd. All rights reserved.

引用

页码：1176 / 1183

页数：8

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