Evaluation of Antioxidant, Antiglycant and ACE-Inhibitory Activity in Enzymatic Hydrolysates of <i>α</i>-Lactalbumin

Abstract

Whey proteins are known for their high nutritional value and bioactivity, notably great potential is found on α-lactalbumin. The objective of this study was to evaluate antioxidant, antiglycant and ACE (angiotensin converting enzyme)-inhibitory activity of α-lactalbumin peptides obtained from enzymatic hydrolysis with Alcalase through different hydrolysis conditions. The optimization of enzymatic hydrolysis was studied by response surface methodology variating enzyme:substrate ratio (0.0050%, 0.0525% and 0.1000% w/w) and time (0, 30 and 60 minutes) measuring antioxidant activity by ABTS and ORAC-FL (response variables), founding an augment of this activity with time. Characterization of seven samples showed increasing hydrolysis with time. Hydrolysate obtained with 0.1000% w/w and 60 minutes demonstrated higher antioxidant activity related to greater hydrolysis. This hydrolysate did not show antiglycant activity but promoted advanced glycation end products formation with methylglyoxal and glucose. In contrast, this sample showed 30% of ACE inhibition when compared to Captopril, having great potential by enhancing hydrolysis.

Bioaccessibility and Cell Metabolic Activity Studies of Antioxidant Low Molecular Weight Peptides Obtained by Ultrafiltration of <i>α</i>-Lactalbumin Enzymatic Hydrolysates

“…Regarding antihypertensive properties measured in vitro, sample 4 LMW presented 22% of ACE inhibition percentage with respect to Captopril. This percentage is similar to the obtained for sample 4 without ultrafiltration, as reported by Fernández-Fernández et al [10] (no significant differences). This could be explained by the fact that the peptides hydrolysis was not enough to release shorter peptides from α-LA which are known to be responsible for ACE inhibitory activity [5].…”

“…showed similar % hydrolysis but in all cases higher than their non-ultrafiltrated counterparts which showed values below 31 [10].…”

“…Optimization of hydrolysis process was carried out as in Fernández-Fernández et al [10] where a composite central design was used [23] based on a response surface model, full factorial design. Briefly, arrangement of seven hydrolysates was generated.…”

“…Antihypertensive activity was determined as described by Cushman and Cheung [29] modified by Kim et al [30] which consists of evaluating the inhibition of angiotensin converting enzyme (ACE). Briefly, samples were prepared as described by Fernández-Fernández et al [10] 4:…”

“…properties [12] [34]. Nevertheless, digestive enzymes could enhance hydrolysis improving antioxidant capacity [10]. LMW hydrolysate from sample 4 to 7…”