Insoluble soybean polysaccharides: Obtaining and evaluation of their O/W emulsifying properties

Abstract

a b s t r a c tThe aims of this work were to obtain different samples of insoluble soybean polysaccharides (ISPS) from defatted soy flour and to study their potential application as O/W emulsifier. In this regard, the insoluble residue (okara) resulting from an aqueous extraction (60 C, pH 9.0), was submitted to an acidic extraction (pH 3.5, 120 C) without or with a pretreatment (high pressure homogenization or sonication). The insoluble residues of these extractions were dried (oven, 70 C or vacuum post-treatment with 2propanol, 40 C) yielding different ISPS samples. Aqueous dispersions of ISPS samples (1e2% w/w, pH 3 and 7), were used to prepare coarse and fine O/W emulsions. Emulsion stability against creaming and coalescence processes, and the rheological behavior were analyzed. ISPS samples obtained by okara pretreatment and vacuum dried post-treatment with 2-propanol allow to produces emulsions with high values of flocculation degree, increasing the stability of the particle size, and allowing the formation of stronger gel-like emulsions. These pretreatments expose internal sites of the polysaccharide and protein structures, increasing their superficial hydrophobicity and, therefore, allow a strong absorption of the macromolecules at the oil-water interface and/or the formation of external layers, increasing the rigidity of the interfacial film and contributing to the formation of hydrated flocs. Also, these treatments could solubilize certain compounds in okara that would interfere negatively in the formation of the interfacial film. Particularly, sample obtained by high pressures homogenization of the okara presented the best emulsifying properties and it was not significantly affected by variations in the pH of the emulsion. The results of this research work demonstrate a high potential of application of the ISPS samples as O/W emulsifier, under acid and neutral conditions, increasing the added value of an important by-product of the soybean industry.

Emulsifying properties of defatted rice bran concentrates enriched in fiber and proteins

“…No changes were observed in the %BS profiles or the %BS average values, so the emulsions were stable against creaming and coalescence. Porfiri et al ., working with insoluble polysaccharides fractions obtained from soybean, reported similar BS values for emulsions prepared under similar conditions …”

“…This reinforces the need to apply treatments that allow their use, such as the reduction of particle size by ultrasound treatment . Proteins are used as emulsifiers due to their ability to prevent droplet aggregation and coalescence, whereas only polysaccharides with sufficient hydrophobic characteristics, or those that are linked to proteins, enable the formation of stable emulsions by adsorbing them at the oil / water interface. Polysaccharides are therefore usually incorporated in emulsions to stabilize the droplets by increasing the viscosity of the continuous phase …”

A Novel Aqueous Extraction for Camellia Oil by Emulsified Oil: A Frozen/Thawed Method

“…At present, proteins, [40] polysaccharides, [41] and phospholipids [42] were widely reported as natural emulsifiers. At present, proteins, [40] polysaccharides, [41] and phospholipids [42] were widely reported as natural emulsifiers.…”

Fabricating a Pickering Stabilizer from Okara Dietary Fibre Particulates by Conjugating with Soy Protein Isolate via Maillard Reaction

“…Dehydrated okara is composed of 55% whole fibre, 21% proteins, 13-14% fats and oils, 1.5% ash and 9-10% moisture [2]. Evidence from a recent study showed that okara insoluble polysaccharides (cellulose, hemicellulose and lignin) have emulsifying and rheological properties [3], and its proteins resemble soy protein isolate [4].…”