High-pressure homogenized citrus fiber cellulose dispersions: Structural characterization and flow behavior

M.R Serial,E Velichko,J.P.M Van Duynhoven,W.G Bouwman,T Nikolaeva,C Terenzi,R Den Adel

doi:10.1016/j.foostr.2021.100237

Abstract

Functionalized biomass waste sources of cellulose have drawn attention due to their high availability and sustainability properties. In this work we characterize the structural and flow properties of high-pressure homogenized citrus fiber cellulose dispersions, employing SAXS, rheology and rheo-MRI techniques. The high-pressure treatment disrupts the microfibrillar network within the citrus fibers, but leaves the individual microfibrils intact. Under moderate shear (0.1-100 s -1 ) in a confined ( < 1 mm) geometry, these functionalized citrus fiber cellulose dispersions exhibit thixotropic shear-banding behavior accompanied by cooperative flow of microfibril flocs with correlation lengths ξ ~ 100 μ m. The presented findings form a basis towards understanding and manipulating the structural and rheological properties of non-wood biomass cellulose microfibrils under industrially-relevant conditions. • Multiscale assessment of high-pressure homogenized citrus fiber dispersions by SAXS. • Quantification of network defibrillation. • Rheo-MRI reveals thixotropy accompanied by cooperative flow behavior.

Highlights

Environmental concerns and diminishing fossil resources are driving the development of renewable bio-based materials for the production of daily life products
After high-pressure homogenization (HPH) treatment at low pressure values (300 bar) the recognized fiber strucures correspond to distrupted cell walls
We have studied the microstructural and flow properties of HPH treated citrus fiber cellulose dispersions

Summary

Introduction

Environmental concerns and diminishing fossil resources are driving the development of renewable bio-based materials for the production of daily life products. More and more effort has been made on finding alternative sources of cellulose that ease the growing demand of wood-based raw materials and improve sus tainability (Pennells, Godwin, Amiralian, & Martin, 2020; Yu et al, 2021). In this respect, citrus peel represents a valuable and sustainable source of cellulose since it contains large amounts of cellular structure and it represents a high percentage of food industry waste (Naz et al., 2016). The insight on the impact of HPH treat ment at structural level is still limited, in particular at the sub-micron scale

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