Historically, food protein quality has been defined by its ability to provide essential amino acids in sufficient quantity where needed after digestion. Therefore, protein quality has been described based on two aspects:
1. Protein source (amino acid profile)
2. Quantity—determining the proportion of amino acids actually absorbed and suitable for direct use by our cells.1
However, proteins are processed before we have access to finished goods. Indeed, depending on food origin, processing, transport and storage, some damaging modifications can impair protein nutritional benefits.2
Protein oxidation. A consequence of lost balance
At cellular level, signaling processes involve free radicals, which are oxidising species continuously generated from oxygen metabolism. The amount of these important molecules is under regulation by the body to establish a balance between oxidising and antioxidant species. If this fine-tuning balance is biased towards an increase of free radicals – oxidative stress – proteins are targets of damage. This degradation leads to their loss of function and the formation of protein aggregates that can become toxic for our cells and body.
From a biomedical approach, protein oxidation is an irreversible modification and its significant role in cellular ageing, neurodegenerative diseases (Alzheimer’s, Parkinson’s), cardiovascular diseases, gastrointestinal disorders, diabetes and cancer has been an attractive scientific research area for decades.3
New technologies, new opportunities
In the food industry, based on new appropriate technologies, scientists started to study the effect of oxidation on protein quality.
Protein oxidation causes an irreversible modification of some essential amino acids reducing their bioavailability. This impairment of amino acids also leads to a modification of protein structure and the formation of aggregates, decreasing the ability of digestive enzymes to degrade them.4-5 As a result, amino acid intake varies according to modifications during food processing. It has also been demonstrated that oxidised proteins have a pro-oxidising effect, resulting in increased oxidative stress.6 Therefore, when we buy protein content finished goods it is healthier to be aware of their protein quality to avoid pro-oxidising effects.
New scientific backed strategies for the food industry
In order to spotlight value chain improvement of protein preservation in finished goods, we test different meat products and protein powders. We used patented technologies to quantify ‘healthy’ proteins (undamaged from oxidative stress) in a sample. This approach allows us to define a quality score associated to protein preservation. The lower the score is (light green in figure), the less the protein has been oxidatively modified during food processing.
In the case of meat finished goods we selected beef, pork and ham to be compared raw and after applying different cooking methods. We also track shelf life impact on protein oxidation on a single piece of beef during a 10-day period.
Protein oxidation as an innovative food quality marker shows that effects from slaughtering, processing methods, storage, packaging, transport and cooking methods in meat-based food could be scientifically targeted for new value-added commercial strategies. Moreover, as healthy proteins decreased during the 10-day sampling of a single beef piece, spotlight for value chain investment could be scientifically backed.
For protein powders we selected eight of the best-selling brands on the market to be compared. Results show that information for consumers brand selection for quality protein could be improved, adding innovative approaches to protein source and quantity facts.
Further investigation is needed but protein oxidation is, for the first time, a valuable food quality marker. It gives an opportunity to manufacturers to meet consumers’ increasing demands for quality and healthy finished goods scientifically backed.
References
- Dietary protein quality evaluation in human nutrition. Consultation, FAO Expert. 2011
- Protein Oxidation in Processed Meat: Mechanisms and Potential Implications on human health. O.P. Soladoye, M.L. Juarez, J.L. Aalhus, P. Shand, and M. Estevez. 2015
- Protein carbonylation in human diseases. Isabella Dalle-Donne, Daniela Giustarini, Roberto Colombo, Ranieri Rossi and Aldo Milzani. 2003
- Effect of Oxidation on In Vitro Digestibility of Skeletal Muscle Myofibrillar Proteins. Véronique Sante-Lhoutellier, Laurent Aubry, Philippe Gatellier. 2007
- Susceptibility of whey protein isolate to oxidation and changes in physicochemical, structural, and digestibility characteristics. Feng, Xianchao & Chenyi, Li & Ullah, Niamat & Cao, Jiqianrui & Lan, Yongli & Ge, Wupeng & Hackman, Robert & Li, Zhixi & Chen, Lin. 2015
- Advanced oxidation protein products induce intestine epithelial cell death through a redox-dependent, c-jun N-terminal kinase and poly (ADP-ribose) polymerase-1-mediated pathway. F Xie, S Sun, A Xu, S Zheng, M Xue, P Wu, J H Zeng & L Bai. s.l. : Nature, 2014
Based in Paris, Oxiproteomics was conceived after several years of cutting edge research in the molecular mechanisms underlying ageing process. Oxiproteomics aims to translate fundamental knowledge to everyday life applications and present accessible science-backed solutions for healthy living and healthy ageing of our society.
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