Elucidation of lipid structural characteristics of chia oil emulsion gels by Raman spectroscopy and their relationship with technological properties

Emulsion gels (EGs) offer interesting possibilities for structuring edible oils and obtaining ingredients with solid-like mechanical characteristics and depending on the ingredients used with healthier properties. In that context, the aim of this study was to develop EGs with chia oil, alginate (as cold gelling agent) and different plant derivatives (oat bran, soy protein isolate and chia flour) with both health benefits and appropriate properties for use for example as animal fat replacers in reduced-fat meat products. To that end, technological properties (pH, colour, texture, etc.) and lipid structure, determined by Raman spectroscopy, were investigated in various chia oil emulsion gels (EGs) prepared with chia oil, alginate and soy protein isolate (SEG), oat bran (OEG) or chia flour (CEG). No noticeable release of exudates was observed in chia oil EGs after processing. pH, colour and textural behaviour (evaluated as puncture force and gel strength) differed (p < 0.05) depending on the composition of the plant ingredients (soy protein, oat bran or chia flour) that contain these EGs. Raman spectroscopic results, particularly significant differences found in area and I/I, revealed differences depending on EG composition in the lipid structure and interactions in terms of lipid acyl chain mobility (order/disorder). These lipid structural characteristics of chia oil EGs correlated significantly with a specific textural feature. The results suggest that chia oil EGs could be developed for use as healthier lipid ingredients in new food systems such as healthier meat products.This research was supported under Projects AGL2014-53207-C2-1-R (MINECO), MEDGAN-CM-S2013/ABI2913 (CAM) and Intramural projects 201470E056 and 201470E073 (CSIC).Peer Reviewe