Food chemicals codex: Part IX. Prepared by the Committee on Specifications of the Food Chemicals Codex of the Food Protection Committee. National Academy of Sciences—National Research Council Publ. 1143, Washington 1965. pp. 92 (October). $25

Abstract

We used two commercial monoglycerides (MGs) with different composition (SKB, ≈ 79% glycerol monostearate and ≈ 12% glycerol monopalmitate; PKB, ≈ 47% glycerol monostearate and 47% glycerol monopalmitate) to develop organogels [2% and 8% (wt/wt) MG content]. The objective was to investigate the effect of shearing (SH) and the presence of 6% ethylcellulose (EC) as factors to limit the sub-α to β polymorphic transition of MG, and the subsequent crystals agglomeration that results in deleterious effect on the organogel's mechanical and oil-binding properties. The results showed that under static conditions (ST) both type of MG developed organogels (OG), but their structure, measured as the complex modulus (G*), was weak particularly in the organogels formulated with PKB at 2%. Nevertheless, the OG-ST had higher strength and lower oil loss than the OG-SH. The X-ray analysis showed that the use of shear during organogelation reduced the time at which the sub-α to β polymorphic transition occurred in both the SKB and the PKB oleogels. Additionally, shearing seemed to hinder the formation of well-organized microplatelet structure, and from there the lack of gelation in the 2% OG-SH and the higher oil loss of the 8% OG-SH compared with their static counterparts. Independent of the concentration of SKB and PKB, the presence of EC resulted in organogels with higher G* than that for OG-ST without EC. This, in spite the EC concentration used was below the critical concentration for vegetable oil gelation. The results showed that EC slowed the rate for the sub-α to β polymorphic transition in the MG organogels. Thus, irrespective of the type of MG and the concentration used, during 14 days of storage at 15 °C the OG-EC systems showed a lower oil loss as a function of time than the corresponding organogels developed without EC. This was particularly evident in the organogels formulated with SKB and those formulated with 8% of MG. We suggest that EC limits the molecular mobility in the MG organogels, and therefore, slows the sub-α to β polymorphic transition and the subsequent β crystals' agglomeration. The results showed that there is a synergistic interaction between MG and EC that result in organogels with higher viscoelastic properties and lower oil loss than those observed in MG-organogels without EC.