Whipped cream-like textured systems based on acidified caseinate-stabilized oil-in-water emulsions

We report on the influence of low levels (≤1 wt%) of an oil-soluble emulsifier LACTEM (lactic acid esters of monoglycerides) on the overrun, stability and rheology of aerated acidified protein-stabilized emulsions (30 vol% groundnut oil or n-eicosane, 2 wt% sodium caseinate). The objective to mimic the textural properties of whipped cream with well-defined model systems in which the foam structure is not stabilized by the conventional mechanism of partial coalescence of semi-crystalline fat globules. Some data are also presented to compare the functionality of LACTEM in these whipped emulsions with other emulsifiers: glycerol monooleate, DATEM (diacetyltartaric esters of monoglycerides) and soybean lecithin. For the non-aerated systems it has been demonstrated that LACTEM partially displaces protein from the emulsion droplet surface and affects the time development of the elastic modulus during acid-induced gelation. Upon whipping to 120% overrun, LACTEM was found to reduce the apparent fracture strain (yield strain) in systems containing either all-liquid droplets (groundnut oil) or all-solid droplets (n-eicosane). In the latter case, it was possible to make aerated acidified emulsion systems as rigid and as brittle as normal whipped cream. Addition of LACTEM was also found to be very effective in enhancing the rigidity and reducing the fracture strain in systems containing a mixture of all-solid and all-liquid droplets. The mechanism of emulsifier action can be attributed to partial displacement of the adsorbed protein, which induces the formation of strong interdroplet crystal–crystal interactions during whipping, thereby conferring the characteristic whipped cream-like texture.