Physicochemical properties of enzymatically modified pea protein‐enriched flour treated by different enzymes to varying levels of hydrolysis

Abstract

Background and objectives Air‐classified pea protein‐enriched flour (PPEF) was modified with trypsin, Savinase, papain, and pepsin to achieve 2%–4% and 10%–12% degrees of hydrolysis, and the surface and functional properties of the hydrolyzed products were assessed. Findings Surface hydrophobicity increased from 13.3 to 48.5 A.U. with papain treatment. Surface charge became more electronegative from −12.6 to −19.0 mV with pepsin treatment. However, solubility of hydrolyzed PPEF at all pH values tested (4.0, 7.0, and 10.0), regardless of enzyme treatment, decreased. Low solubility of hydrolyzed proteins negatively impacted solubility‐dependant functional properties: foaming properties and emulsifying properties decreased. However solubility‐independent properties (water‐ and oil‐holding capacity; WHC and OHC, respectively) improved with proteolysis, increasing from 0.6 g/g to 1.4–2.0 g/g and from 0.7 g/g to 1.0–1.5 g/g, respectively. Conclusions Papain treatment yielded the best results in terms of both OHC and WHC of PPEF. Significance and novelty The resultant hydrolyzates have potential for baked goods and processed meat applications because of their increased OHC and WHC.

The improvement of the functional properties of a chickpea protein isolate through proteolysis with three proteases

“…Consequently, a one‐factor analysis of variance (ANOVA) found that hydrolysis did not have a significant ( p < .01) impact on FC relative to the untreated isolate for any of the three pH conditions. Decreases to FC upon following treatment were assumed to be a consequence of increased hydrophobic protein–protein interactions decreasing protein activity at the interfacial layer (Konieczny et al, 2019; Wani et al., 2015). In addition, relatively high levels of deviation prevented significant ( p < .01) differences from being noted between the hydrolysates at pH 4 and 7.…”

“…However, hydrophobicity did not progressively increase with higher levels of hydrolysis. Increases in hydrophobicity were initially anticipated, as hydrolysis was expected to increase the access of the ANS reagent to the hydrophobic amino acid residues within the interior of the CPI proteins (Humiski & Aluko, 2007; Konieczny et al, 2019). Therefore, the lack of any substantial increase in hydrophobicity following increased enzyme treatment could indicate that the protein molecules had been wholly denatured during sample preparation.…”

“…Emulsifying activity index (EAI) and emulsifying stability index (ESI) were determined based on the method of Konieczny et al (2019). Protein solutions were prepared in Milli‐Q water at a concentration of 1% (w/w) and adjusted to pH 4.0, 7.0 or 10.0 using 0.5 M HCl and NaOH, followed by stirring for 16 hr at 4°C.…”

“…Hydrolysis of the CPI was carried out based on the methods of Konieczny et al (2019) with some variations. First, samples were prepared by mixing 50 g of untreated CPI overnight at 4°C into 5 L of 50 mM phosphate, held at pH 7.5 for trypsin hydrolysates, and pH 6.2 for papain hydrolysates.…”

“…Solubility was determined according to the procedure of Konieczny et al (2019). Samples of 100 mg were dispersed in 10 ml of Milli-Q water and adjusted to pH 4.0, 7.0 or 10.0 using 0.5 N HCl and 0.5 N NaOH.…”