Freeze-thaw stability of oilseed rape oleosome emulsions

A - Papers appearing in refereed journals

Bramante, F., Di Bari, V., Adams, G., Beaudoin, F., Waschatko, G., Jakobi, R., Billecke, N. and Gray, D. A. 2025. Freeze-thaw stability of oilseed rape oleosome emulsions. Journal of Food Engineering. 392 (May), p. 112471. https://doi.org/10.1016/j.jfoodeng.2025.112471

AuthorsBramante, F., Di Bari, V., Adams, G., Beaudoin, F., Waschatko, G., Jakobi, R., Billecke, N. and Gray, D. A.
Abstract

This work investigated the stability of natural oleosome emulsions on freeze-thawing. Oleosomes were recovered from oilseed rape seeds following an aqueous extraction process using sodium bicarbonate (0.1 M). The final emulsions pH was adjusted to 9, 6 and 3 to achieve surface charge values of −50.3 ± 1.6, −20.0 ± 2.4, and +37.5 ± 0.5 mV, respectively. The emulsions with lipid mass fraction of 0.28 ± 0.02 were cooled to −20 °C for up to 24 h and thawed at 20 °C for 18 h, and their freeze-thaw stability assessed quantifying amount of released oil (oil yield) due to emulsion destabilisation. The destabilisation of the oleosome emulsions at pH 9 and 6 increased with isothermal holding time at −20 °C, whereas the emulsion at pH 3 destabilised more rapidly. Differential scanning calorimetry analysis of emulsions cooled from 20 °C to −20 °C at −10 °C/min, and held at −20 °C for 8h, revealed how the continuous phase rapidly crystallised on cooling, whereas lipid crystallisation started after 2 h at −20 °C and continued for the following 3 h. Oil yield data combined with differential scanning calorimetry curves suggest that the oleosome emulsions at pH 9 and 6 destabilised along with crystallisation of the dispersed lipid phase, whereas emulsions at pH 3 destabilised with the continuous phase crystallisation. It was hypothesised that oleosome emulsions at pH 9 and 6 ruptured by a mechanism of partial coalescence. At pH 3 the electrostatic interaction between phospholipids and oleosin molecules, the main components of oleosome interface, may be reduced resulting in a weaker interface which on cooling can be easily disrupted by ice crystals. Oil yield data for emulsions with increasing continuous phase mass fraction (0.50 and 0.70) suggest a lower extent of destabilisation than control (0.28 continuous phase). Increasing the number of freeze-thaw cycles from one to three did not cause significant increase in the oil yield.

Year of Publication2025
JournalJournal of Food Engineering
Journal citation392 (May), p. 112471
Digital Object Identifier (DOI)https://doi.org/10.1016/j.jfoodeng.2025.112471
Open accessPublished as ‘gold’ (paid) open access
FunderUniversity of Nottingham
Biotechnology and Biological Sciences Research Council
Publisher's version
Output statusPublished
Publication dates
Online15 Jan 2025
Publication process dates
Accepted08 Jan 2025
PublisherElsevier

Permalink - https://repository.rothamsted.ac.uk/item/99329/freeze-thaw-stability-of-oilseed-rape-oleosome-emulsions

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