Novel antihypertensive peptides from lupin protein hydrolysate: An in-silico identification and molecular docking studies.

Application of non-thermal treatment to proteins prior to enzymatic hydrolysis can facilitate the release of novel bioactive peptides (BPs) with unique biological activities. In this study, lupin protein isolate was pre-treated with ultrasound and hydrolysed using alcalase and flavourzyme to produce alcalase hydrolysate (ACT) and flavourzyme hydrolysate(FCT). These hydrolysates were fractionated into 1, 5, and 10 kDa molecular weight fractions using a membrane ultrafiltration technique. The in vitro angiotensin-converting enzyme (ACE) studies revealed that unfractionated ACT (IC50 = 3.21 mg mL-1) and FCT (IC50 = 3.32 mg mL-1) were more active inhibitors of ACE in comparison to their ultrafiltrated fractions with IC50 values ranging from 6.09 to 7.45 mg mL-1. Molecular docking analysis predicted three unique peptides from ACT (AIPPGIPY, SVPGCT, and QGAGG) and FCT (AIPINNPGKL, SGNQGP, and PPGIP) as potential ACE inhibitors. Thus, unique BPs with ACE inhibitory effects might be generated from ultrasonicated lupin protein.

In-Silico Analysis and Antidiabetic Effect of α-Amylase and α-Glucosidase Inhibitory Peptides from Lupin Protein Hydrolysate: Enzyme-Peptide Interaction Study Using Molecular Docking Approach.

The use of natural ingredients for managing diabetes is becoming more popular in recent times due to the several adverse effects associated with synthetic antidiabetic medications. In this study, we investigated the in vitro antidiabetic potential (through inhibition of α-glucosidase (AG) and α-amylase (AA)) of hydrolysates from lupin proteins pretreated with ultrasound and hydrolyzed using alcalase (ACT) and flavourzyme (FCT). We further fractionated ACT and FCT into three molecular weight fractions. Unfractionated ACT and FCT showed significantly (p < 0.05) higher AG (IC50 value = 1.65 mg/mL and 1.91 mg/mL) and AA (IC50 value = 1.66 mg/mL and 1.98 mg/mL) inhibitory activities than their ultrafiltrated fractions, where lower IC50 values indicate higher inhibitory activities. Then, ACT and FCT were subjected to peptide sequencing using LC-MS-QTOF to identify the potential AG and AA inhibitors. Molecular docking was performed on peptides with the highest number of hotspots and PeptideRanker score to study their interactions with AG and AA enzymes. Among the peptides identified, SPRRF, FE, and RR were predicted to be the most active peptides against AG, while AA inhibitors were predicted to be RPR, PPGIP, and LRP. Overall, hydrolysates prepared from lupin proteins using alcalase and flavourzyme may be useful in formulating functional food for managing diabetics.

Enhancing the Biological Activities of Food Protein-Derived Peptides Using Non-Thermal Technologies: A Review.

Bioactive peptides (BPs) derived from animal and plant proteins are important food functional ingredients with many promising health-promoting properties. In the food industry, enzymatic hydrolysis is the most common technique employed for the liberation of BPs from proteins in which conventional heat treatment is used as pre-treatment to enhance hydrolytic action. In recent years, application of non-thermal food processing technologies such as ultrasound (US), high-pressure processing (HPP), and pulsed electric field (PEF) as pre-treatment methods has gained considerable research attention owing to the enhancement in yield and bioactivity of resulting peptides. This review provides an overview of bioactivities of peptides obtained from animal and plant proteins and an insight into the impact of US, HPP, and PEF as non-thermal treatment prior to enzymolysis on the generation of food-derived BPs and resulting bioactivities. US, HPP, and PEF were reported to improve antioxidant, angiotensin-converting enzyme (ACE)-inhibitory, antimicrobial, and antidiabetic properties of the food-derived BPs. The primary modes of action are due to conformational changes of food proteins caused by US, HPP, and PEF, improving the susceptibility of proteins to protease cleavage and subsequent proteolysis. However, the use of other non-thermal techniques such as cold plasma, radiofrequency electric field, dense phase carbon dioxide, and oscillating magnetic fields has not been examined in the generation of BPs from food proteins.

Improving the enzymolysis efficiency of lupin protein by ultrasound pretreatment: Effect on antihypertensive, antidiabetic and antioxidant activities of the hydrolysates.

This study evaluated the impact of ultrasound pretreatment (UP) and enzyme type (flavourzyme, alcalase) on amino acid composition, antihypertensive, antidiabetic, and antioxidant activities of lupin protein hydrolysate (LPH). The UP altered molecular weight of the hydrolysates as revealed by SDS-PAGE and MALDI-TOF and their surface hydrophobicity and thermal stability. Amino acid analysis revealed that glutamic acid, aspartic acid, arginine, and leucine were the dominant amino acids lupin protein. Generally, sonicated hydrolysates exhibited higher biological activity than non-sonicated samples and the original LPI. Alcalase hydrolysate pretreated for 10 min showed the highest DPPH and metal chelating activities. Highest ACE inhibitory activity was observed in flavourzyme hydrolysate after 5 min of UP, while maximum α-amylase and glucosidase inhibitory activity was achieved after 10 min of UP in flavourzyme hydrolysate. The results obtained in this study demonstrated the potentials of UP as a valuable tool for enhancing the biological activity of lupin proteins.

The effect of harvest times on bioactive properties and fatty acid compositions of prickly pear (Opuntia ficus-barbarica A. Berger) fruits.

In the study, the impact of harvest time on total phenolic content, antioxidant activity, and phenolic compounds of prickly pear (Opuntia ficus-barbarica A. Berger) fruit pulp and the oil content and fatty acids profile of the seed were investigated. The highest total phenolic content was determined as 156.77 mg/100 g in July 1 harvest, while the maximum antioxidant activity and total oil content were found as 9.81% and 6.80% at the last stage of maturation (15 August), respectively. The highest oleic (28.51%), palmitic (22.61%) and stearic acid contents (9.20%) in seed oil were observed in June 15 harvest. The highest value for linoleic acid (57.50%) was detected in August 15 harvest. Prickly pear is a vital source of bioactive constituents such as phenolic and antioxidant substances in terms of being useful for human health and the optimum harvesting time to retain high quantities of most phenolic compounds is 1st July.

Effect of pepsin and SO2 treatments on yield and properties of starch from Tabat and Wad-baco sorghum cultivars.

This study aims to evaluate the effect of pepsin and SO2 treatments on the yield and physicochemical-, functional-, and color properties of starches isolated from Tabat and Wad-baco sorghum cultivars. Results revealed that starch yield from treatments B (steeping for 7 h; 3 h in distilled water, 4 h in 0.1 M sodium acetate buffer, pH 4.5), BE (steeping for 7 h; 3 h in distilled water, 4 h in 0.1 M sodium acetate buffer, pH (4-4.5) with 250 mg pepsin), BES (steeping for 7 h; 3 h in distilled water, 4 h in 0.1 M sodium acetate buffer, pH 4.5 with 250 mg pepsin and 0.2% SO2), and S (steeping for 7 h; 3 h in distilled water, 4 h in 0.2% SO2) were significantly higher than that from the control (A; steeping for 24 h in 0.2% SO2) in both cultivars. The combination of pepsin and SO2 treatment (BES) produced an increased starch yield of 78.90% and 85.56% from Tabat and Wad-baco, respectively. Micrographs showed hydrolysis of the protein matrix attached to the starch by pepsin, which created holes on the surface of starch granule. Gelatinization temperature decreased in the treated starches from both cultivars compared to control. Water- and fat- absorption capacities were higher in the starch from all treatments compared to control. Generally, enzyme treatment improved the yield and functional properties of starches from both cultivars.

Effect of isolation techniques on the characteristics of pigeon pea (Cajanus cajan) protein isolates.

In this study, the effect of different isolation techniques on the isolated proteins from pigeon pea was investigated. Water, methanol, ammonium sulfate, and acetone were used for the precipitation of proteins from pigeon pea. Proximate composition, and antinutritional and functional properties of the pigeon pea flour and the isolated proteins were measured. Data generated were statistically analyzed. The proximate composition of the water-extracted protein isolate was moisture 8.30%, protein 91.83%, fat 0.25%, ash 0.05%, and crude fiber 0.05%. The methanol-extracted protein isolate composition was moisture 7.87%, protein 91.83%, fat 0.17%, and ash 0.13%, while crude fiber and carbohydrates were not detected. The composition of the ammonium sulfate-extracted protein isolate was moisture 7.73%, protein 91.73%, fat 0.36, ash 0.13%, and crude fiber 0.67%. The acetone-extracted protein isolate composition was moisture 8.03%, protein 91.50%, ash 0.67%, and fat 0.30%, but crude fiber and carbohydrates were not detected. The isolate precipitated with ammonium sulfate displayed the highest foaming capacity (37.63%) and foaming stability (55.75%). Isolates precipitated with methanol and acetone had the highest water absorption capacity (160%). Pigeon pea protein isolates extracted with methanol and ammonium sulfate had the highest oil absorption capacity of 145%. Protein isolates recovered through acetone and methanol had the highest emulsifying capacity of 2.23% and emulsifying stability of 91.47%, respectively. The proximate composition of the recovered protein isolates were of high purity. This shows the efficiency of the extraction techniques. The isolates had desirable solubility index. All the isolation techniques brought significant impact on the characteristics of the isolated pigeon pea protein.