Oleogels developed with recovered sunflower waxes as organogelant agent

REDONDAS, CINTIA; BAÜMLER, ERICA; CARELLI, AMALIA

Córdoba

Congreso; VII Congreso Internacional de Ciencia y Tecnología de Alimentos (CICyTAC); 2018

Ministerio de Ciencia y Tecnología de la provincia de Córdoba

In this work, oleogels of high oleic sunflower oil (HOSO) and recovered sunflower wax (SW) from oil tank settling were developed. HOSO was characterized by analyzing its fatty acid (FA) composition, peroxide value (PV), acidity (A), tocopherols content (TTs) and tocopherol composition (α-T, β-T and γ-T). To evaluate the influence of the concentration of SW (C) and the gelling temperature (TG) in the oleogel, a three-level factorial experimental design with two variables (32) was used. The factor levels chosen were: TG= 5, 15 and 25 ºC; C= 1.5, 2.5 and 3.5%. The responses measured were hardness, fracturability, adhesiveness and oil binding capacity (OBC) expressed as a function of the weight difference before and after centrifugation of the oleogels. The texture parameters were measured by performing two penetration cycles in samples at 5 ºC. The thermal behavior of oleogels was studied through DSC and its microstructure was visualized by optical light microscopy, polarized light microscopy and SEM. Oleogels were formulated by adding different percentages of waxes (wt%) in the oil, previously heated to 80 ºC. The oil-wax mixture was maintained at 80 ºC for 5 min, with continuous stirring, after which, it was poured in cylindrical containers (height= 20mm, i.d.= 35mm) and stored at TG for 24 h. Prior to analysis, the formed oleogels were kept at 5 ºC for 24 h. HOSO presented the following characteristics: PV= 6.92 ± 0.11 mEq peroxide oxygen/kg; A= 0.05 ± 0.01% oleic acid; FA (wt%) were: C16:0= 3.38 ± 3,.59. 10-02, C16:1= 0.11 ± 1,.46. 10-02, C18:0= 2.30 ± 2,.19. 10-02, C18:1= 87.27 ± 3,.65. 10-02, C20:0= 0.21 ± 2,.74. 10-03, C20:1= 0.28 ± 3,.15. 10-03, C22:0= 0.81 ± 1,.19. 10-02 and C24:0= 0.28 ± 8,.58. 10-03; TTs= 680.56 ± 16.29 mg/kg; α-T= 97.35%, β-T= 2.20% and γ-T= 0.45%. Values between 0.29-1.63 N for hardness, 0.30-1.43 N for fracturability and 0.53-3.20 N.s for adhesiveness were obtained from the texture analysis. In addition, the OBC values were between 64.54-86.00%. The optimum condition (higher response values) corresponded to C= 3.5%, while the weakest one was for C= 1.5%, been TG= 5 ºC in both circumstances. These two conditions were analyzed by DSC. From the experimental design it was concluded that C was the most influential parameter, having a positive effect in the textural parameters and OBC, while TG had a negative effect. From DSC analysis it was observed that an increment in C resulted in an increase not only in TF (55.18 to 59.47 ºC) and its corresponding ΔHF (2.29 to 6.02 J/g), but also in TC (48.55 to 53.74 ºC) and ΔHC (0.88 to 2.28 J/g). By analyzing the microstructure of the oleogels generated at the same TG a denser crystal network was observed as C increased, whereas comparing oleogels developed at the same C the size of SW crystals reduced as TG decreased, generating a more compact network. In addition, a continuous three-dimensional network of SW microplatelets was observed through SEM.