Sugar Beet Extract (Beta vulgaris L.) as a New Natural Emulsifier: Emulsion Formation

Abstract

The interfacial and emulsion-forming properties of sugar beet extract (Beta vulgaris L.) were examined and compared to a Quillaja extract that is widely used within the food industry. We investigated the influence of extract concentration on surface activity at oil-water and air-water interfaces and on the formation of oil-in-water emulsions (10% w/w, pH 7). Sugar beet extract reduced the interfacial tension up to 38% at the oil-water interface, and the surface tension up to 33% at the air-water surface. The generated emulsions were negatively charged (ζ ≈ -46 mV) and had the smallest particle sizes (d) of ∼1.3 μm at a low emulsifier-to-oil ratio of 0.75:10. Applying lower or higher extract concentrations increased the mean particle sizes. The smallest emulsions were formed at an optimum homogenization pressure of 69 MPa. Higher homogenization pressures led to increased particle sizes. Overall, sugar beet extract showed high surface activity. Furthermore, the formation of small emulsion droplets was successful; however, the droplets were bigger compared to those from the Quillaja extract. These results indicate sugar beet as an effective natural emulsifier that may be utilized for a variety of food and beverage applications.

Formation and stability of emulsions stabilised by Yucca saponin extract

“…Yucca saponin extract was analysed for its mineral, protein and sugar content (% w/w) according to previously described methods (Ralla et al ., ,c).…”

“…). These values are similar to other commercially available emulsifiers such as the synthetic sodium dodecyl sulphate (γ OW = 3 mN m −1 ; γ AW = 35 mN m −1 ), Tween 20 (γ OW = 2 mN m −1 ; γ AW = 40 mN m −1 ) and natural Quillaja saponins (γ OW = 5 mN m −1 ; γ AW = 35 mNm −1 ) , but lower than those reported for other natural emulsifiers such as gum arabic (γ OW = 7–47 mN m −1 ; γ AW = 50 mN m −1 ) and β‐casein (γ OW = 20 mN m −1 ; γ AW = 50 mN m −1 ) (McClements, ; McClements & Gumus, ; Ralla et al ., ). The calculated CMC AW of Yucca saponin extract was around 0.1% ( Fig.…”

“…The increasing demand for ‘natural’ products has led to increasing interest of the food industry to identify and characterise new surfactants of natural origin (Ozturk & McClements, ). Such natural surfactants include the group of saponins that can be extracted from a variety of plants such as Quillaja , sugar beet and oat (Ralla et al ., ,c). Saponins are small molecular weight molecules with polar sugar moieties attached to a triterpene or steroid backbone that is typically highly nonpolar, which makes them amphiphilic and thus highly surface‐active.…”

Value addition of red beet (Beta vulgaris L.) by‐products: Emulsion formation and stability

“…Saponins were quantified through separation and identification of saponin containing fractions by ultra‐performance liquid chromatography (UPLC‐ToF‐MS) as described in our previous reports (Ralla et al ., ,c). Semi‐quantification was carried out by separation of red beet extract with the help of medium‐pressure liquid chromatography (MPLC) and weighing of the individual fractions.…”

“…The excellent emulsifying performance of Quillaja extract has led to overexploitation of this exotic tree, which is native in the Andean region. To respond to the above‐mentioned major trends within the food industry, we previously characterised extracts obtained from by‐products such as sugar beet (Ralla et al ., ,c) and oat bran (Ralla et al ., ) to investigate further applications as naturally‐derived emulsifier. Similarly, large amounts of red beet peel accumulate during industrial processing that are mainly used as animal feed.…”