Oleogel Fabrication Based on Sodium Caseinate, Hydroxypropyl Methylcellulose, and Beeswax: Effect of Concentration, Oleogelation Method, and Their Optimization

Abstract

In the present study, the oleogel preparation with hydroxypropyl methylcellulose (HPMC) (0-2 g/100 g), sodium caseinate (CN) (0-4 g/100 g), beeswax (0-5 g/100 g), and oleogelation method (foam and emulsion template) was optimized using response surface methodology (RSM) to attain the desirable oil retaining ability, rheological, and textural characteristics. For all the chosen responses, the quadratic model was the best-fitting model with a determination coefficient of R 2 > 0.91. Results exhibited that the HPMC and CN concentrations were the most influential tested factors on the oil binding capacity, textural, and rheological characteristics of the oleogels due to the formation of more complex and strong network. There was a significant improvement in oil binding capacity and structure recovery of samples by beeswax addition. To produce oleogel similar to industrial shortening, the optimization method was done based on maximum oil binding capacity and thixotropic recovery and other responses were chosen equal to those of shortening values (ɳ a = 330 Pa.s, G 0 = 276,543 Pa, A value = 164,308 Pa s rad −1 , and firmness = 44.99 g). As regards the optimized level of structuring agents and responses (ɳ a = 317 and 329 Pa.s, G 0 = 249,782 and 260,997 Pa, A value = 180,022 and 180,373 Pa s rad −1 , and firmness = 44.37 and 36.98 g corresponding to Optimization 1 and Optimization 2, respectively), fabrication of oleogels with at least 90 g/100 g trans-free and low saturated oil and attributes close to industrial shortening is possible.Keywords Oleogel Á Sodium caseinate Á Hydroxypropyl methylcellulose Á Beeswax J Am Oil Chem Soc (2020) 97: 485-496.

Preparation of Protein Oleogels: Effect on Structure and Functionality

“…This leads to the formation of a high internal phase emulsion (HIPE), consisting of a three-dimensional network of polymers filled with liquid oil. The dried emulsions are obtained by drying in an oven at elevated temperatures [85][86][87][88][89][90], by freeze-drying [85,88,89], or by drying at room temperature [84]. In these systems, the oil itself is not structured, but is held together in a network of proteins and polysaccharides.…”

“…In some cases, such a stable interface was already obtained by using proteins only. Abdolmaleki et al [88] and Alizadeh et al [90] prepared oleogels using 2% sodium caseinate [88,90], and Tavernier et al [86] showed that also soy protein isolate (SPI) could be used to create an emulsion stable enough to obtain oleogels at a protein concentration of 2.5%. This was explained by the formation of a relatively thick interfacial protein layer [86].…”

“…Similar to the emulsion-templated approach, also the foam-templated approach is based on freeze-drying of a previously prepared foam. After the drying step, oil is then added to the obtained dried foam-templates until saturation is reached [92,93], or the template is immersed in oil to let the dried foam absorb the oil in its voids [90,94]. As the oil is added later, the final amount of incorporated oil depends on the absorption capacity of the dried foams (aerogels).…”

“…Additionally for foams, it is important that the interfaces are stable enough to prevent coalescence of the air bubbles during drying. Although stable systems have been found with proteins only (gelatin, sodium caseinate) [90,92], additional polysaccharides are often added, such as xanthan gum [92,93], hydroxypropyl methylcellulose [90], and alginate [94]. In the case of the gelatin-based foam, additional polysaccharides were not a required component to obtain a sufficiently stable foam, but the addition of xanthan considerably increased the oil sorption capacity of the resulting cryogels [92].…”

“…In the case of the gelatin-based foam, additional polysaccharides were not a required component to obtain a sufficiently stable foam, but the addition of xanthan considerably increased the oil sorption capacity of the resulting cryogels [92]. Sodium caseinate alone was sufficient to form a foam-templated oleogel, but addition of hydroxypropyl methylcellulose increased the gel strength [90]. After the oil is absorbed by the dried foam, a continuous protein-polysaccharide network with oil in the voids as the dispersed phase is obtained.…”