Functional properties of plant proteins. Part 2. Selected physicochemical properties of native and denatured protein isolates from faba beans, soybeans, and sunflower seed

Abstract

Functional propertiesas solubility, water and oil adsorption, emulsifying capacity. emulsion activity and stabilityof protein isolates from faba beans, soybeans and sunflower seed depending on the isolation process were determined.Proteins isolated under mild conditions, it means by precipitation using dialysis or dilution of salt extracts with water, show the highest solubility, characterized by a sharp minimum of solubility at a rather narrow range of pH. An incubation of the precipitated proteins at low pH (pH 2) results in a decrease of the solubility on the alcaline and acidic part of the solubility profile.On the contrary to the decreased solubility, the proteins denatured by acid show an increased water adsorption capacity. Depending on the kind of protein and the conditions of preparation these values can reach the manifold ones of the control. Smaller increases of oil adsorption in acid-denatured proteins were found, too.The emulsion activity and stability were not or only slightly influenced, but the emulsifying capacity was strongly decreased by the denaturation procedure. The emulsifying capacity was influenced by the solubility of the protein, but a strong correlation does not exist.The high water adsorption of Promine D can be reached by the other plant proteins after denaturation. The sunflower protein showed the highest emulsifying capacity.Increasing the pH from the isoelectric range to 7 improves all studied functional properties.'

Impact of thermal treatment versus cold atmospheric plasma processing on the techno-functional protein properties from Pisum sativum ‘Salamanca’

“…For the determination of the FBC, the method by Schwenke (1981) was used. 0.5 g (±0.009 g) of the respective pea flour fraction were weighed into a centrifuge beaker and stirred with 5 mL of commercial rape seed oil using a propeller stirrer and an overhead agitator (Yellowline Ò , IKA Ò OST basic, New Jersey, USA) two times for 60 s at 1000 rpm with a five-minute intermission in between (the stirring steps).…”

“…The required amount of water was calculated by the method of Smith (1978a), modified by Schwenke (1981). Therefore 0.5 g (±0.009 g) of the pea flour were weighted into a centrifuge beaker and stirred (60 s) with 2.5 mL of water using a propeller stirrer and an overhead agitator (Yellowline Ò , IKA Ò OST basic, New Jersey, USA).…”

Functional properties of plant proteins Part IV. Foaming properties of modified proteins from faba beans

“…Nitrogen solubility profiles were determined as described under [2]. Emulsifying properties were determined as described under [7]. Fig.…”

Gelation of a broad bean (Vicia faba L. minor) protein fraction (prepared at pH 2) in dependence on some influencing factors

“…SHEHATA et al 1251 extract the protein fromphmeo1u.v aurus at different pH, he observes a maximum in solubility at pH 2. SCHWENKE et al [23] incubate plant proteins at pH 2 but they do not extract the proteins which are soluble at this pH. They observe, among other things, a decrease of the solubility of the proteins.…”