Impact of water degumming and enzymatic degumming on gum mesostructure formation in crude soybean oil

Tatiana Nikolaeva,Tim Rietkerk,Arjen Sein,Robert Dalgliesh,Wim G Bouwman,Evgenii Velichko,Bei Tian,Henk Van As,John Van Duynhoven

doi:10.1016/j.foodchem.2019.126017

Abstract

Phospholipid gum mesostructures formed in crude soybean oil after water degumming (WD) and enzymatic degumming (ED) were studied at a range of phospholipid and water concentrations. For ED, phospholipase C (PLC), phospholipase A2 (PLA2) and a mixture of phospholipases Purifine 3G (3G) were used. Both WD and ED resulted in lamellar liquid-crystalline phases, however, of different topology. The dependence of the bilayer spacings (as observed by SANS and SAXS) on the ratio between amount of water and amphiphilic lipids differed for WD and PLA2 ED vs PLC and 3G ED. This difference was also observed for dynamics at molecular scale as observed by time-domain (TD) NMR and attributed to partial incorporation of diglycerides and free fatty acids into gum bilayers after PLC and 3G ED. Feasibility of using TD-NMR relaxometry for quantification of the gum phase and estimation of degumming efficiency was demonstrated.

Highlights

Degumming is a major refining step to remove phospholipids (PLs) as gums from crude oils, in order to obtain high qualitative edible oil products (Dijkstra, n.d.; Sagalowicz et al, 2016)
We found that gums were up to 25% enriched by DGs and free fatty acids (FFAs), and hypothesized that these were present as structural component in the bilayer parts
We compared the sum of the p(gumr) and p(gumm) proton populations for the full system consisting of oil and gum by TD-NMR

Summary

Introduction

Degumming is a major refining step to remove phospholipids (PLs) as gums from crude oils, in order to obtain high qualitative edible oil products (Dijkstra, n.d.; Sagalowicz et al, 2016). More detailed structural investigations on the impact of the different degumming treatments on gum mesostructures are lacking. Our current insights in the mesoscale structure of gum-like systems are mainly based on binary models consisting of single PLs and water (Kučerka, Pencer, Sachs, Nagle, & Katsaras, 2007; Nagle & Tristram-Nagle, 2000) In these binary model systems, PLs occur as bilayers separated by water layers, comprising a swollen lamellar liquid-crystalline phase, mostly existing as curved mesostructures, such as multi-lamellar vesicles and stacks of bilayers, either planar or curved on the micron scale. No systematic study as to date has been carried out on the impact of ED on polar lipid composition and resulting gum mesostructure. We investigated whether TD-NMR T2 relaxometry can be used to quantify the amount of gum in gum/oil dispersions upon the various degumming treatments

Methods

Results

Conclusion