Ultrasound-assisted adsorption/desorption for the enrichment and purification of flavonoids from baobab (Adansonia digitata) fruit pulp

Balarabe B Ismail; Hauwa L Yusuf; Yunfeng Pu; Huanhuan Zhao; Mingming Guo; Donghong Liu

doi:10.1016/j.ultsonch.2020.104980

Ultrasound-assisted adsorption/desorption for the enrichment and purification of flavonoids from baobab (Adansonia digitata) fruit pulp

Ultrason Sonochem. 2020 Jul:65:104980. doi: 10.1016/j.ultsonch.2020.104980. Epub 2020 Jan 21.

Authors

Balarabe B Ismail¹, Hauwa L Yusuf², Yunfeng Pu³, Huanhuan Zhao⁴, Mingming Guo⁵, Donghong Liu⁶

Affiliations

¹ College of Biosystems Engineering and Food Science, National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang R & D Center for Food Technology and Equipment, China; Department of Food Science & Technology, Faculty of Agriculture, Bayero University, Kano PMB 3011, Kano, Nigeria.
² Department of Food Science & Technology, Faculty of Agriculture, Bayero University, Kano PMB 3011, Kano, Nigeria.
³ Department of Food Science, Tarim University, Alar 843300, China.
⁴ College of Biosystems Engineering and Food Science, National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang R & D Center for Food Technology and Equipment, China.
⁵ College of Biosystems Engineering and Food Science, National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang R & D Center for Food Technology and Equipment, China; Fuli Institute of Food Science, Ningbo Research Institute, Zhejiang University, Hangzhou 310058, China. Electronic address: mingguo@zju.edu.cn.
⁶ College of Biosystems Engineering and Food Science, National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang R & D Center for Food Technology and Equipment, China; Fuli Institute of Food Science, Ningbo Research Institute, Zhejiang University, Hangzhou 310058, China. Electronic address: dhliu@zju.edu.cn.

PMID: 32203917
DOI: 10.1016/j.ultsonch.2020.104980

Abstract

This work described the purification and enrichment of flavonoids from baobab (Adansonia digitata) fruit pulp (BFP) by ultrasound-assisted adsorption/desorption procedure using macroporous resins. Four resins were tested and HPD-500 polar resin exhibited the best adsorption/desorption properties. Based on preliminary experiments and literature reports, the effects of various ultrasonic conditions including high power short time (HPST, 540 W for 5 min), medium power medium time (MPMT, 270 W for 15 min) and low power long time (LPLT, 45 W for 30 min) as well as different temperatures (T = 25-45 °C) on the adsorption of Total Flavonoids Content (TFC) were investigated in comparison with orbital shaking/no sonication (NS). Also, the effect of ultrasound on the desorption capacity and recovery of TFC was determined at different concentrations of ethanol (30-100%). Remarkably, ultrasonic treatment significantly increased the adsorption/desorption capacity and recovery and shortened the equilibrium time. The pseudo-second-order kinetic and Freundlich isotherm models better delineated the adsorption process under ultrasound. Moreover, the adsorption process was both spontaneous and thermodynamically favourable with physical adsorption and multilinear intraparticle diffusion being the predominant mechanisms of the whole process. HPST treatment at 25 °C with 80% ethanol as the desorption solvent most noticeably enhanced the adsorption/desorption of flavonoids and contributed to the highest recovery of TFC, Total Phenolic Content (TPC), and antioxidant capacity in addition to a 5-8-fold reduction in total sugar and acid contents when compared with NS treatment. Moreover, HPLC analysis revealed that the content of nine out of thirteen phenolic compounds from the HPST treatment was the highest, and the individual flavonoids content increased by 2-3-fold compared with the other treatments. Our analyses suggested that ultrasound can be employed as a practical approach to intensify the adsorption and desorption of functional compounds in BFP.

Keywords: Adsorption/desorption kinetics; Antioxidant capacity; Baobab fruit pulp; Flavonoids; Ultrasound-assisted purification.

MeSH terms

Adansonia / chemistry*
Adsorption
Antioxidants / isolation & purification*
Ethanol / chemistry
Flavonoids / isolation & purification*
Fruit / chemistry*
Plant Extracts / isolation & purification*
Porosity
Resins, Synthetic / chemistry*
Solvents / chemistry
Sonication / methods*
Thermodynamics

Substances

Antioxidants
Flavonoids
Plant Extracts
Resins, Synthetic
Solvents
Ethanol