Macroalgae suspensions prepared by physical treatments: Effect of polysaccharide composition and microstructure on the rheological properties

Loredana Malafronte,Secil Yilmaz-Turan,Annika Krona,Marta Martinez-Sanz,Francisco Vilaplana,Patricia Lopez-Sanchez

doi:10.1016/j.foodhyd.2021.106989

Abstract

The use of macroalgae in food products is growing due to their techno-functionality and nutritional properties. In this context, an increased understanding of the rheological properties which are relevant for manufacturing and texture is needed. Here we investigated the impact of thermal and mechanical treatments, including high pressure homogenisation (HPH), on the polysaccharide composition, microstructure, and rheological properties of brown algae Laminaria digitata suspensions (5 wt %). Monosaccharide analysis and immunolabeling of alginate in combination with confocal laser scanning microscopy, revealed a sequential release of different polysaccharides as result of the applied shear. Results showed that thermal treatment (70 °C 1 h) and mild shear lead to suspensions of clusters of cells and release of fucoidan and laminarin into the liquid phase, conferring shear thinning properties to the suspensions. High pressure homogenisation was able to completely break the macroalgae cells, reducing particle size and releasing other soluble polysaccharides, in particular alginate, conferring gel properties (G'>G'') to the suspensions. This study contributes to the knowledge of how to design sustainable, innovative and nutritious liquid/semiliquid food products containing macroalgae biomass.

Highlights

The transformation of the food chain is key for the achievement of the United Nations Sustainable Development Goals related to promote healthy diets and reduce environmental impact
Research on exploitation of seaweed biomass has been continuously growing in the last decades, because of their high content of economi cally important components such as polysaccharides, proteins, poly unsaturated fatty acids (PUFA) including omega-3 fatty acids, and antioxidants (Scieszka & Klewicka, 2019), which are used in the chemical, pharmaceutical and food industries
An enhancement of protein and bioethanol yields from Laminaria digitata was achieved by disrupting cell walls and hydrolysing cell wall polysaccharides (Hou, Hansen, & Bjerre, 2015); and agar extraction was combined with bioethanol production to optimise utilisation of Gracilaria verrucosa (Kumar, Gupta, Kumar, Sahoo, & Kuhad, 2013)

Summary

Introduction

The transformation of the food chain is key for the achievement of the United Nations Sustainable Development Goals related to promote healthy diets and reduce environmental impact. An increased number of studies focuses on a biorefinery approach, starting from the whole seaweed and sequentially extracting the multiple high value compounds for different applications, including biofuels (Wei, Quarterman, & Jin, 2013). Taking this biorefinery approach, an enhancement of protein and bioethanol yields from Laminaria digitata was achieved by disrupting cell walls and hydrolysing cell wall polysaccharides (Hou, Hansen, & Bjerre, 2015); and agar extraction was combined with bioethanol production to optimise utilisation of Gracilaria verrucosa (Kumar, Gupta, Kumar, Sahoo, & Kuhad, 2013)

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Conclusion