|Dietary protein sources: You better eat them before they're rancid.|
The impact of PROTOX, as this form oxidation is called to distinguish it from the way better known LOX (lipid oxidation) on human health was, at that moment, wholly unknown.
As Estévez and Luna point out in a recent paper in the peer-reviewed scientific journal "Critical Reviews in Food Science and Nutrition", PROTOX has been in the focus during the succeeding decades, though, "owing to the association between the oxidative damage to proteins and aging and age-related diseases (Berlett & Stadtman, 1997)" (Estévez. 2016).
Earl R. Stadtman (*1919–†2008), a renowned biochemist of the 20th century and mentor of various Novel-prized scientists, was one of the pioneers in unveiling the chemistry and biological consequences of PROTOX. From the elucidation of mechanisms whereby the rates of metabolic reactions match to the necessities of the living cell, he identified the connection between unbalanced oxidative metabolism (≈ oxidative stress) and impaired physiological processes (Stadtman, 1990).
"While some of the underlying mechanisms of the connection between in vivo PROTOX and disease are still to be clarified, it is accepted that PROTOX plays a role in aging and age related diseases such as Alzheimer’s, Parkinson’s, inflammatory Bowel’s (IBD), rheumatoid arthritis, diabetes, muscular dystrophy, and cataractogenesis, among others (Berlett & Stadtman, 1997).
Figure 1: Oxidative damage to poultry: Sources of oxidative stress, impact of oxidation, and antioxidant strategies (Estévez. 2015).
On account of the effort of brilliant scientists, the ‘poor cousin’ of lipid oxidation is now extolled as a topic of the utmost scientific interest" (Estévez. 2016).Now that you know all that, I suspect that you are asking yourself what this "protein oxidation" has to do with "Food Science and Nutrition". Well, the answer is actually pretty simple: While PROTOX has been for decades disregarded as a major cause of food deterioration, it does play a major role in foods from nutritional, sensory and technological points of view. Note: There will be a follow up to this article, next week with answers to your questions, such as (1) How can I avoid protein oxidation when preparing protein containing meals? (2) Which foods are the most susceptible? (3) If processing is an issue won't protein powders be the worst offenders? Not your question? Feel free to post additional questions you may have here.