Potential of using fish oil encapsulated with plant proteins to fortify shortbread cookies and dark chocolate: Effect on sensory perception, volatiles and storage stability

Abstract: Fish oil, from either fatty fish or food supplements, is the main source of health promoting n-3 long chain polyunsaturated fatty acids (PUFAs) in the human diet. Although the health benefits of n-3 PUFAs are well established, their dietary intake is not at the recommended level. Fortification of foods with n-3 rich oils could improve the dietary intake levels of PUFAs. However, the main challenge for fortification with n-3 oils is their low tolerance to processing due to low oxidative stability creating issues with flavor and storage stability.

To overcome this challenge, in this study fish oil was encapsulated by spray-drying using novel formulations of pea, soy and sunflower proteins in combinations with whey protein or maltodextrin before fortification of two food models (shortbread cookies and dark chocolate). Flavor characteristics were studied by generic descriptive analysis and volatile products by solid-phase microextraction with gas chromatography-mass spectrometry. A six months storage test at room temperature was conducted to evaluate the oxidative stability of the models.

Encapsulation by spray-drying increased the oxidative stability of fish oil. The best protection was achieved with formulations with pea or soy protein with whey protein. The most promising formulations were successfully used in the developed food models. Fortification affected the texture, odor, and flavor compared to the control without fish oil. For both fortified models, the use of pea protein with maltodextrin resulted in least fishy flavor and odor and resembled the texture of control the most. Volatile profiles could be differentiated based on fortification and encapsulation material. This was mainly due to compositional and textural changes affecting the release of volatiles. Both non-encapsulated oil and whey protein formulations performed well with regard to oxidative stability for both food models. The pea protein formulations used in the cookie model showed the greatest overall potential for fortification.