In this study, we aimed to carry out the efficient fortification of vanilla milkshakes
with micro-encapsulated microalgae oil (brand: S17-P100) without distorting the product’s
odor. A 10-step oil-enrichment protocol was developed using an inclusion rate of 0.2
to 2 w/w%. Fatty acid (FA) profile analysis was performed using methyl esters with
the GC-MS technique, and the recovery of docosahexaenoic acid (C22:6 n3, DHA) was
robust (r = 0.97, p < 0.001). The enrichment process increased the DHA level to 412
mg/100 g. Based on this finding, a flash-GC-based electronic nose (e-nose) was used
to describe the product’s odor. Applying principal component (PC) analysis to the
acquired sensor data revealed that for the first four PCs, only PC3 (6.5%) showed
a difference between the control and the supplemented products. However, no systematic
pattern of odor profiles corresponding to the percentages of supplementation was observed
within the PC planes. Similarly, when discriminant factor analysis (DFA) was applied,
though a classification of the control and supplemented products, we obtained a validation
score of 98%, and the classification pattern of the odor profiles did not follow a
systematic format. Again, when a more targeted approach such as the partial least
square regression (PLSR) was used on the most dominant sensors, a weak relationship
(R2 = 0.50) was observed, indicating that there was no linear combination of the qualitative
sensors’ signals that could accurately describe the supplemented concentration variation.
It can therefore be inferred that no detectable off-odor was present as a side effect
of the increase in the oil concentration. Some volatile compounds of importance in
regard to the odor, such as ethylacetate, ethyl-isobutarate, pentanal and pentyl butanoate,
were found in the supplemented product. Although the presence of yeasts and molds
was excluded from the product, ethanol was detected in all samples, but with an intensity
that was insufficient to cause an off-odor.
