Dromedary Milk Protein Hydrolysates Show Enhanced Antioxidant and Functional Properties

Abstract

Research background. Milk protein hydrolysates have received particular attention due to their health-promoting effects. Dromedary milk differs from the milk of other dairy animals in the composition and structure of its protein components, which give it unique properties. The bioactivity and functionality of whole dromedary milk proteins and their enzymatic hydrolysates have not received much attention, hence this study aims to investigate the effect of enzymatic hydrolysis of dromedary milk proteins on their antioxidant activities and functional properties. Experimental approach. Dromedary milk proteins were treated using four proteolytic enzymes (pepsin, trypsin, α-chymotrypsin and papain) and two mixtures of enzymes (pancreatin and pronase). The degree of hydrolysis was measured to verify the hydrolysis of the proteins. The sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration chromatography served to determine the molecular mass distribution of the hydrolysates while reversed phase-high performance liquid chromatography (RP-HPLC) was conducted to explore their hydrophobicity. The antioxidant activities were evaluated using various in vitro tests, including 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging capacities, iron(III) reducing ability and chelating activity. Besides, functional properties such as solubility, foaming and emulsification were assessed. Results and conclusions. Dromedary milk protein hydrolysates exhibited different degrees of hydrolysis ranging from 17.69 to 41.86 %. Apart from that, the hydrolysates showed different electrophoretic patterns, molecular mass distribution and RP-HPLC profiles demonstrating the heterogeneity of the resulting peptides in terms of molecular mass and polarity. The hydrolysates displayed significantly higher antioxidant capacities than the undigested proteins at all the tested concentrations. Iron(II) chelating activity was the most improved assay after proteolysis and the hydrolysate generated with pancreatin had the highest chelating power. Dromedary milk protein hydrolysates possessed good solubility (>89 %). Further, foaming and emulsifying properties of dromedary milk proteins were enhanced after their proteolysis. These interfacial properties were influenced by the enzymes employed during proteolysis. Novelty and scientific contribution. Enzymatic hydrolysis of dromedary milk proteins is an effective tool to obtain protein hydrolysates with great antioxidant and functional properties. These results suggest that dromedary milk protein hydrolysates could be used as a natural source of antioxidant peptides to formulate functional foods and nutraceuticals.

Amino acids and protein profiles of defatted camel and cow milk fractions: correlation with their in vitro antioxidant and antidiabetic activities

“…It was found that acid extraction of milk enables the production of milk fractions that have lower TPC than the equivalent skim milk, while TPC contents of water/ethanol extracts show higher values of TPC than those obtained in HCl/ethanol extracts with a significant variability between fractions. While many authors have reported on the antioxidant activities of various milk forms, including liquid milk ( 16 , 30 ), fermented milk ( 15 ), milk hydrolysates ( 16 , 31 ), and heat-treated milk ( 30 ), there is a relative scarcity of reports focusing on sweet, acid whey, or casein fractions ( 17 , 25 ). Moreover, within the same milk species, the outcomes fluctuated depending on the specific antioxidant assay employed (DPPH assay, ABTS assay, iron-binding capacity) and the kind of product studied (unprocessed milk, processed dairy products, or milk extracts).…”

Breastfeeding Situation in Saudi Arabia and Recent Approaches in The Development of Follow-on Formula for Facing Breastfeeding Difficulties

“…As seen in Table (1), if infant formula becomes an option to replace breastfeeding, much effort must be made to closely mimic the nutritional profile of human breast milk for normal infant growth and development (Martin et al, 2016). According to Codex Alimentarius and European Commission regulations, the levels of macronutrients and micronutrients in infant formula must be specified to simulate the composition of breast milk (Oussaief et al, 2020). Formula composition and functionality must include and balance protein content and profile, i.e., predominant whey protein profile and αlactalbumin fortification; the profile of fatty acids, the content of carbohydrates, vitamins and minerals with those in breast milk (Drapala et al, 2016).…”

“…Its popularity is because it has become one of the most promising foods regards to its potential antioxidant and antimicrobial activities derived from caseins and whey proteins (Osman et al, 2015 andJrad et al, 2020). Camel milk differs from the milk of other species and is closest to human milk, especially in terms of its lack of β-lactoglobulin and the low amounts of κ-casein, which makes it a suitable diet for people with cow's milk protein allergy (Hochwallner et al, 2014;zibaee et al, 2015;Jrad et al, 2020 andOussaief et al, 2020). Furthermore, it was reported that camel milk is rich in vitamin C, iron and potassium contents and low in fat and lactose contents (Gopal et al, 2017).…”

“…Furthermore, it was reported that camel milk is rich in vitamin C, iron and potassium contents and low in fat and lactose contents (Gopal et al, 2017). It has unique bioactive peptides released during the gastrointestinal digestion of milk proteins (Oussaief et al, 2020). Nevertheless, it was reported that camel whey protein is considered a strong natural antioxidant because it decreases oxidative stress, enhances immune system function, and increases glutathione levels and it is rich in lactoferrin, lactalbumin, lactoglobulins, lactoperoxidase, and lysozyme, and is rich in immunoglobulins (Badr et al, 2017).…”

In Vitro Digestibility Assessment of Whey from Goat and Camel Milk Fermented with Lactobacillus helveticus for Use as a Base in Formulating Follow-On Formula

“…Because of the higher similarity of camel and goat milks in composition to human milk compared to cow milk (Table 1), infant formulas have been predominantly manufactured using camel and goat milks and their proteins to provide a suitable protein source that is healthier and more easily digestible for infants [17,[21][22][23]. Camel milk is distinct from the milk of other species and bears a resemblance to human milk, owing to its low levels of κ-casein and the absence of β-lactoglobulin.…”