The study, published in Food Hydrocolloids, investigated the composition of extracts obtained from solid olive processing waste and tested their potential as high added-value food emulsifiers – finding that the processing waste yields efficient emulsifiers that have potential for use in food and beverage applications.
“Olive waste, a major pollutant in the Mediterranean and in other areas, could be used as to reclaim high added value food hydrocolloids,” wrote the study authors, led by Andreas Filotheou from ATEI of Thessaloniki, Greece.
According to the team, the material obtained using direct extractions from the waste products provided emulsifiers comprising of macromolecular aggregates and smaller molecules.
Tests suggested significant differences in the dynamics of adsorption of different extracts and in their equilibrium interfacial tension are related to their emulsifying capacity and emulsion stability.
“When tested as emulsifiers, the dialysis-isolated macromolecular populations alone are moderately efficient emulsifiers, as compared to the full extracts. Smaller molecules present in the extract appear to provide a synergistic effect in the overall emulsification capacity,” wrote Filotheou and colleagues.
“Solid olive processing waste can yield emulsifiers fit for use in neutral and acidic oil–in–water emulsions,” they reported.
The team noted that the olive oil industry continues to be one of the most heavily polluting among the food industries in Southern Europe, adding that olive by-products are among the primary waste produced in the Mediterranean.
According to the team, analysis of the extracts from solid olive processing waste showed that the products comprise of polysaccharide agglomerates, proteins and their hydrolysis products, ‘among other constituents.
They revealed that at pH 7 and pH 5, the alcohol-insoluble solid processing waste is an effective emulsifier for acidic and non-acidic model food emulsions, “while their zeta potential values are negative at both pH.”
Meanwhile, significant differences in the dynamics of adsorption of different extracts - and in their equilibrium interfacial tension – were found to be related to their emulsifying capacity and emulsion stability.
Analysis showed that most macromolecular components are interfacially adsorbed, while smaller molecules provide a synergistic effect in the overall emulsification capacity
“Although the macromolecular components are interfacially-adsorbed, it is the synergy with smaller molecules that renders them efficient emulsifiers,” wrote the team.
Source: Food Hydrocolloids
Published online ahead of print, doi: 10.1016/j.foodhyd.2015.02.029
“Novel emulsifiers from olive processing solid waste”
Authors: Andreas Filotheou, et al