Functional Properties of Lupinus angustifolius Seed Protein Isolates

Abstract

Protein isolates prepared by alkaline solubilization followed by isoelectric precipitation and freeze-drying from six varieties of Lupinus angustifolius (Haags Blaue, Sonate, Probor, Borlu, Boregine, and Boruta) grown in Mexico were evaluated for functional properties: nitrogen solubility, water-holding capacity (WHC), oil holding capacity (OHC), emulsion activity index (EAI), emulsion stability index (ESI), foaming capacity (FC), foam stability (FS), and gelling minimum concentration (GMC). The nitrogen solubility values, WHC, OHC, and FC did not show significant differences between the protein isolates. The solubility of the isolates was minimal at pH of 4.0 and 5.0 while the regions of maximum solubility were found at pH of 2.0 and 10.0. There were significant differences in EAI and ESI depending on the varieties used. The isolates of the Boregine and Borlu varieties showed the highest EAI with 29.3 and 28.3 m 2 g −1 , respectively, while the lowest index was recorded in the isolate obtained from the Sonate variety (24.6 m 2 g −1 ). Like solubility, these indices also increased at both extremes of pH evaluated; both properties were minimal in the isoelectric pH range (4.0 to 5.0).

Lupinus angustifolius L. cultivar “Boregine” from South of Bulgaria: a source of nutrients and natural biologically active components

“…The protein content of the examined lupin seeds was 23.9%, which confirmed that these seeds belonged to the legumes with high total protein content (23.0-31.33%) (Iqbal et al, 2006;Bakoglu et al, 2009;Kökten et al, 2010) and possessed a high nutritional value. The obtained results corresponded to the findings from previous authors who reported that the total proteins in lupin seeds ranged from 28.4 to 45.8% (Sedláková et al, 2016;Tarasenko et al, 2017;Bartkiene et al, 2016;Mohamed and Rayas-Duarte, 1995;Lara-Rivera et al, 2017). On the other hand, these seeds had rather low oil content (7.4%) but it was higher than those in other seeds from Fabaceae family (1.0-3.0%).…”

“…The studies on lupin seeds worldwide are focused mainly on their chemical composition as follow: oil content (3.88-12.58%), proteins (28.4-45.9%), carbohydrates (41.60-51.68%), starch (3.00-10.26%), fibres (8.05-22.20%), ash (2.9-4.8%), non-nitrogenous extracts (285.9-436.5 g/kg) (Mohamed and Rayas-Duarte, 1995;Bartkiene et al, 2016;Sedláková et al, 2016;Lara-Rivera et al, 2017;Tarasenko et al, 2017) and the lipid composition comprises the fatty acid composition, the total and individual tocopherol composition, and the total content of sterols and phospholipids. The composition of the seeds varies within certain limits and depends on the type of lupin, the geographical location, and the climatic conditions in which the respective plant species are grown.…”

Functional properties of Australian blue lupin (Lupinus angustifolius) protein and biological activities of protein hydrolysates

“…The emulsifying property of blue lupin protein was determined, and the emulsifying activity index (EAI) was calculated to be 41.78 m 2 /g, and the emulsifying stability index (ESI) was 15.34 min (Table 1). The EAI value of L. angustifolius is reported as 29.3 m 2 /g and ESI as 14.9 min by Lara‐Rivera et al (2017). It is reported in the literature that, for casein, EAI = 175.6 m 2 /g and ESI = 33.79 min (Luo, Pan, & Zhong, 2014).…”

“…The results showed that the foaming capacity of blue lupin protein isolate is higher (124% and 128%) at acidic and alkaline regions (pH 2 and 10, respectively) and lower (116%) at the isoelectric region (pH 6). Six Mexican varieties of L. angustifolius were studied in the literature that exhibited lower foaming capacities in the range of 116.3 to 116.8% at neutral pH (Lara‐Rivera et al, 2017). These results are consistent with the results presented in this paper for blue lupin protein.…”

“…Lampart‐Szczapa et al (2006) observed emulsifying activities of three lupin species in the range of 11.4–12.2 m 2 /g and EAI is 7.4–8.4 min. L. angustifolius showed better emulsifying activity than white lupin varieties indicating its higher surface hydrophobicity (Lampart‐Szczapa et al, 2006; Lara‐Rivera et al, 2017).…”