Invited review: Whey proteins as antioxidants and promoters of cellular antioxidant pathways

Abstract

Oxidative stress contributes to cell injury and aggravates several chronic diseases. Dietary antioxidants help the body to fight against free radicals and, therefore, avoid or reduce oxidative stress. Recently, proteins from milk whey liquid have been described as antioxidants. This review summarizes the evidence that whey products exhibit radical scavenging activity and reducing power. It examines the processing and treatment attempts to increase the antioxidant bioactivity and identifies 1 enzyme, subtilisin, which consistently produces the most potent whey fractions. The review compares whey from different milk sources and puts whey proteins in the context of other known food antioxidants. However, for efficacy, the antioxidant activity of whey proteins must not only survive processing, but also upper gut transit and arrival in the bloodstream, if whey products are to promote antioxidant levels in target organs. Studies reveal that direct cell exposure to whey samples increases intracellular antioxidants such as glutathione. However, the physiological relevance of these in vitro assays is questionable, and evidence is conflicting from dietary intervention trials, with both rats and humans, that whey products can boost cellular antioxidant biomarkers.

Bioactives from Agri-Food Wastes: Present Insights and Future Challenges

“…Whey is generated in huge volumes that can cause serious environmental problems, but, it is also recognized as an important source of proteins with excellent nutritional and functional properties which are widely used in various food product development. Whey proteins are also an important source of bioactive peptides obtained by enzymatic hydrolysis exhibiting antioxidant and anti-hypertensive properties [157,173]. Whey protein fraction is recovered as retentate after microfiltration; and the generated permeate is rich in carbohydrates including lactose and other oligosaccharides.…”

Study of Extraction and Enzymatic Properties of Cell-Envelope Proteinases from a Novel Wild Lactobacillus plantarum LP69

“…Enzymatic hydrolysis is an extensively used method, which contributes to the production of protein hydrolysates with improved functional, nutritional and physiological properties [26]. Corrochano et al [27] have confirmed that hydrolysates from whey proteins exhibit radical scavenging activity and reducing power. Furthermore, whey protein hydrolysate hydrolyzed by the purified CEP showed strong ACE-inhibitory activity [1].…”

Interactions of Whey Proteins with Metal Ions

“…β-Lactoglobulin is the major bovine whey protein, accounting for approximately 10% of the total protein in bovine milk and approximately 50% in ruminants [2], but it is not present in human milk. β-LG contains 162 amino acid residues, which form nine antiparallel β-sheets [3]. It belongs to the lipocalin family and has the ability to bind different hydrophobic molecules [4], which can be useful for reducing allergenicity owing to its covalent conjugation to flavonoids because β-LG is one of the major milk allergens responsible for cow milk allergy [5].…”