Triacylglycerol composition, physico-chemical characteristics and oxidative stability of interesterified canola oil and fully hydrogenated cottonseed oil blends

Muhammad Imran, Muhammad Nadeem

Partial hydrogenation process is used worldwide to produce shortening, baking, and pastry margarines for food applications. However, demand for such products is decreased during last decade due to their possible links to consumer health and disease. This has raised the need to replace hydrogenation with alternative acceptable interesterification process which has advantage in context of modifying the physico-chemical properties of edible fat-based products. Therefore, the main mandate of research was the development of functional fat through chemical interesterification of canola oil (CaO) and fully hydrogenated cottonseed oil (FHCSO) mixtures. Blends were prepared in the proportions of 75:25 (T1), 50:50 (T2) and 25:75 (T3) of CaO:FHCSO (w/w). Interesterification was performed using sodium methoxide (0.2 %) as catalyst at 120 °C, under reduced pressure and constant agitation for 60 minutes. The non-interesterified and interesterified CaO:FHCSO blends were evaluated for triacylglycerol (TAG) composition, physico-chemical characteristics, oxidative stability and consumer acceptability at 0, 30 and 60 days of storage interval. The oleic acid (58.3 ± 0.6 %) was predominantly present in CaO while the contents of stearic acid (72 ± 0.8 %) were significantly higher in FHCSO. Maximum trisaturated (S3) contents (63.9 ± 0.5 %) were found in T3 while monounsaturated (S2U), diunsaturated (U2S) and triunsaturated (U3) contents were quite low in T2 and T3 before interesterification. A marked reduction in S3 and U3 contents with concomitant increase in S2U and U2S contents was observed for all CaO:FHCSO blends on interesterification. During storage, the changes in S3, S2U and U2S contents were not found significant (p ≥ 0.05). However, maximum decrease 13 %, 7.5 and 5.6 % in U3 contents for T1, T2 and T3 was noted after 60-days of interesterification, respectively. The Lovibond color R, melting point, refractive index, specific gravity, peroxide and free fatty acids values of CaO:FHCSO blends decreased after interesterification and increased within the permissible limits during storage (p ≥ 0.05). The CaO:FHCSO blends maintained their sensory acceptability before and after interesterification which decreased significantly as storage length increased from days 30 to 60-days. Most important was the 50 % CaO:50 % FHCSO blend (T2) which possessed the desirable TAG profile, physico-chemical and sensory characteristics coming from T1 and T3. The present study concludes that functional lipids with desirable characteristics can be developed through interesterification of 50 % CaO:50 % FHCSO blend and should be explored as ingredient for the production of various healthier products for discerning consumers.