RESUMO
A coarse canola oil-in-water (O/W) emulsion (dispersed mass fraction 0.1) was prepared by adding oil to whey protein hydrolysate (WPH)-citric pectin (CP) soluble complex (1% total biopolymer weight; WPH to CP mass ratio 6:1; pH 4.25) aqueous phase using a high shear homogenizer (4000 rpm, 2 min). The coarse O/W emulsion was further homogenized to obtain emulsions (Ex) with different mean droplet sizes (4000, 3000, 120 and 60 nm). A full-fat yogurt (YC; 26 ± 0.3 g milk fat L-1) was prepared from reconstituted whole milk powder (WMP, 3% milk fat) and skim milk powder (SMP, 0.01% milk fat). Reduced-milk fat yogurt (YEx 13 ± 0.3 g milk fat L-1) variations were prepared from WMP + SMP + Ex, where Ex substituted 50% of the milk-fat contained in YC. The viscosity and viscoelastic moduli were lower for YEx than for YC; the effect was more pronounced for E60 and E120. Aroma was non-significantly different between YC and YEx. A multivariate analysis showed that YEx overall acceptability was linked to taste and after taste attributes and to the viscosity perceived in mouth. The loss modulus showed anti-correlation directionality with the overall acceptance. The smaller mean droplet sized YEx exhibited the highest overall acceptability. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-022-05573-3.
RESUMO
Recently the structuring of liquid oils with low molecular weight organogelators has received much attention. Food products devoid of trans fats, with tailored rheological and textural properties can be designed for desired applications by properly selecting the organogelator and cooling rate used in their formation. Nevertheless, studies regarding these points are still scarce. In this work the effect of two different food-grade gelators (glyceryl monostearate, GM and sorbitan monostearate, SM) and different cooling rates (1, 3 and 9⯰C/min) on the microstructural, viscoelastic and texture properties of chia seed oleogels (GMO and SMO, respectively) were evaluated. Gelator and chia seed oil (ChSO) were mixed in 1:10 mass ratio. SMO formed crystalline needle-like structures, with faster cooling rates producing smaller crystals (higher crystallinity index) and a more compact network. GMO showed an opposite crystallinity index dependence with cooling rate than SMO. GMO hardness higher than that of SMO, and increased while that of SMO decreased as cooling rate was faster. Both GMO and SMO showed a thixotropic dependence of the storage (G') and loss (G") moduli with forward-backward temperature ramp (5-80-5⯰C). Both moduli values were higher for GMO than for SMO independently of cooling rate used. A thixotropic index was obtained, which reflected that GMO had a more thermo-reversible structure than SMO. The results of this study indicate that the formation mechanism of chia seed oleogels was affected by the cooling rate and the chemical nature of the gelator, and elicited completely different microstructural and mechanical responses.