Author: Herr Dr. Amoneit
Last saved by: Saritas, Sevim

Linseed Oil Nanoemulsions using High Pressure Homogenization 
M. Rubilar^a,b, E. Morales^a,b, K. Dumorné^a, B. Garrido^a, G. Alarcón^a, F. Acevedo^a,b, 
C. Shene^a,b
^aScientific and Technological Bioresource Nucleus, BIOREN, Universidad de La Frontera, Casilla 54-D, Temuco, Chile
^bAgriaquaculture Nutritional Genomic Center, CGNA, Technology and Processes Unit, Francisco Salazar 01145, Department of Chemical Engineering, UFRO, Temuco, Chile

Nanoemulsions for the delivery of bioactive compounds are particularly suitable for food applications, because these can be fabricated with food compatible ingredients and by scalable top-down approaches such as high-pressure homogenization (HPH).
The objective of this study was to evaluate the conditions of HPH for optimizing the particle size (PS) of linseed oil nanoemulsion. First, a Plackett Burman factorial design was carried out to identify the factors with a significant effect on the PS. The factors oil concentration (5-10%), emulsifier concentration (0.2-0.5%), homogenization pressure (700-1400 bar), passing times (2-4 passes) and type of emulsifier (Tween 20-80) were evaluated. The coarse emulsion of linseed oil, water and emulsifier (5000 rpm, 10 min) was fed to a laboratory unit HPH. The PS was measured in a Malvern Zetasizer Nano ZS and the data obtained were analyzed with the software Expert Desing 6.0. The model obtained was significant with a coefficient of determination (R^2) of 0.99. All the factors studied showed a significant effect (p<0.05) on the PS response. To optimize the HPH conditions an experimental Taguchi design was applied using the criterion smaller is better with a matrix L_4(2^3) with three-independent variables: emulsifier concentration (Factor A, 0.2-0.5%), oil concentration (Factor B, 1-5%), and homogenization pressure (Factor C, 700-1400 bar). The lowest PS  was obtained with the high emulsifier concentration (0.5%), low oil concentration (1%) and high homogenization pressure (1400 bar). This combination ensures optimal process conditions for obtaining nanoemulsions. The ANOVA demonstrated that the R^2 for the factors C, A and B were 57.8, 29.9 and 12.2%, respectively. R^2 of 99.9% for these three variables was significant (p<0.05) indicating a high association of factors with the PS. 
Our results confirm that Taguchi’s methodology can be used in the quality control of HPH nanoemulsion development.
Acknowledgements. Fondecyt project 1130639 from the Universidad de La Frontera.