Isolation and characterization of protein isolated from defatted cashew nut shell: Influence of pH and NaCl on solubility and functional properties

Abstract

This work reports the isolation of protein from defatted cashew nut shell (CNS), with the crude protein product containing 91.07% protein. Under its natural conditions, the solubility of this protein isolate is comparable (74.02%) to that of mustard green meal protein. The solubility of the protein isolate decreases with decreasing pH, with the minimum solubility observed at its isoelectric point (pH 3). The water holding capacity, oil holding capacity, foaming capacity, foam stability, emulsifying capacity and emulsion stability were found to be 2.56 cm 3 H 2 O/g protein, 4.28 cm 3 oil/g protein, 76.88%, 70.98%, 62.0% and 79.0%, respectively. The profiles of these functional properties were determined with varying pH values and NaCl concentrations, and improved properties were observed in the alkaline pH range and in the presence of NaCl. Electrophoretic analysis showed that the high molecular weight protein globulin was the major protein in the protein isolate.

Functional and physicochemical properties of a protein isolate from Alu Prot -CGNA: A novel protein-rich lupin variety ( Lupinus luteus )

“…The highest WAC values were found at pH 2 (3.01 cm 3 H 2 O/g protein) and pH 10 (1.71 cm 3 H 2 O/g protein). At neutral pH, WAC was equal to 1.68 cm 3 H 2 O/g protein, higher than that of L. angustifolius protein isolates (0.24 to 0.45 cm 3 H 2 O/g protein) (Lqari et al, 2002) and lower than that of protein isolated from defatted cashew nut shell (2.56 cm 3 H 2 O/g protein) (Yuliana et al, 2014). WAC is an index of the ability of proteins to absorb and retain water, which in turn influences the texture and mouth feel characteristics of foods and food products, like comminuted meats, extenders or analogues, and baked dough (Adebowale, Adeyemi, & Oshodi, 2005).…”

“…Thus, at pI the repulsive forces of proteins are weak, favoring droplets emulsion coalescence and hence a poor emulsifying stability. On the contrary, when the electrical charge around oil droplets is high, repulsion forces help maintaining droplet repulsion and retarding emulsion coalescence (Yuliana et al, 2014). Although the highest EC value for LPIA (61.91%) is lower than that for soy protein isolate (74.7%), as an emulsifier, LPIA formed more thermally-stable emulsions than soy protein isolate (73.2%), except at pI (Franzen & Kinsella, 1976).…”

“…The addition of salt (up to 100 mM) weakens the hydrophobic binding among protein molecules, enhancing the interaction through hydrophilic functional groups. This better cohesion between proteins improves rheological properties of foam (Yuliana et al, 2014). However, Lawal et al (2005) reported that at high NaCl concentration, salt ions screen protein interaction because of saltingout effect, even promoting aggregation, precipitation and flocculation.…”

Physicochemical and functional properties of protein isolate produced from Australian chia seeds

“…The foam stability (FS) was evaluated by measuring the total volume after 2 hour of the foam formation and was calculated according to Yuliana et al (2014) using equation (3).…”

Physical, Proximate and Functional Properties of Flour and Protein Isolate from Four γ-Irradiated Groundnut Cultivars

“…These values are in agreement with the value reported by Atuonwu and Akobundun [52] for pumpkin seed protein isolate (2.0%). Lawal et al [53] and Yuliana et al [54] also reported that lower least gelation capacity gave better gelation capacity and increase in ionic strength enhances gelation properties. The slight difference in gelation concentration of the defatted flour and isolates may be ascribed to the relative ratios of different constituents such as proteins, carbohydrates, and lipids that make up the flours and also the interactions between such components.…”