The worldwide demand in dietary protein for human nutrition increases as a result of the demographic expansion and the increase in protein consumption in recently industrialized countries. There is a need to develop sources of proteins, such as plant proteins, that are more sustainable than animal proteins although there are of lower quality.
Three oil seeds will be studied: sunflower, rapeseed and flax seed. From these plants, oil is produced for human nutrition and fuel whereas cakes are used for animal feeding. Proteins from cakes are an important supply but their potential for human alimentation must be questioned. There are several barriers to overcome. These project has 3 objectives: <br />* To optimize the extraction and purification processes to obtain isolates with a good efficiency and a limited effluent production <br />* To produce acceptable food products including these isolates <br />* To assess the bioavailability of protein and amino acids, using the standard but invasive methods requiring ileal digesta sampling. An alternative and less invasive multi-tracer method will be developed.
The extraction and purification of proteins from oil cakes is still insufficiently worked out. Technological processes must be optimized to increase the yield and remove most of non-desirable associated molecules, while minimizing the use of effluents to fit with sustainability requirements. The protein extraction yields resulting from industrial oil extraction are currently low. Moreover, associated compounds are present in the extracts, like phenolic compounds that interact with proteins during extraction and purification and colors proteins. An original multicriteria optimization approach based on extraction and purification modeling will lead to find out the appropriate operating conditions for producing protein isolates with satisfying purity, extraction yield and colour.
Only one study on ileal protein digestibility of rapeseed was performed in humans, and not data exist on sunflower and flaxseed. Moreover, FAO has recommended evaluating the bioavailability of individual amino acids rather than the global protein. The main bottleneck is the complexity and the invasiveness of procedures to determine such coefficients that require collecting the ileal effluents. We’ll develop and validate on a novel dual isotopic method that was proposed in a FAO committee expert report. The principle is to intrinsically label the oilseed proteins with 15N and/or 2H and to mix them in an experimental meal with a standard 13C protein. The comparison of isotopic signatures of amino acids in the meal and in blood will reflect the relative digestibility of the oilseed amino acids compared to the standard protein. This method will be evaluated and compared to the direct evaluation in the digesta in healthy volonteers using nasoileal tubes.
Rapeseed and sunflower were labelled with 2H and 15N. The pilot labeling of sunflower in greenhouse was successful, in terms of yield and isotopic enrichments. The 2H labeling was unsuccessful in field conditions, but 15N enrichment and yield were good. Rapeseed was labeled in pots. The isotopic enrichments were acceptable but the yield was low compared to what was planned.
Production of isolates :
Conditions to optimize extraction and purification were found for sunflower and rapeseed. The optimal sets of parameters were obtained. Labelled sunflower isolates were produced.
Preliminary work was done to extract oil flax seed, and difficulties for protein purification were encountered due to mucilage.
Biscuits with a good acceptability were produced, including 15% of sunflower or rapeseed isolates.
In vivo bioavailability of sunflower
Amino acid bioavailability of sunflower was measured in rats. Protein digestibility was 94 % using 15N and 96 % using 2H tracer. Individual amino acid digestibility ranges between 94.2 and 96 % for valine and methionine, respectively. Values obtained with 2H are consistent although 2 % higher. The DIAAS was 0.93 for lysine, indicating a modest deficiency in this amino acid, and above 1 for all other amino acids. Plasma amino acid enrichments were measured 3 and 6 h after the meal. Data analysis is ongoing.
• To optimize flax seed isolate production
• To label the flax seed with 15N. Deuterium labeling in field appeared to be unsuccessful.
• To produce labeled rapeseed isolate
• To produce biscuits including labeled isolates
• To start the in vivo investigations in Humans. The protocole was approved by the ethical committee SudMed4 and authorized by the ANSM.
Romain Tessier, Nadezda Khodorova, Juliane Calvez, Julien Piedcoq, Romain Kapel, Francis Cacérès, Aurélie Dinar, Daniel Tomé, Claire Gaudichon. Digestive bioavailability of spirulina and sunflower proteins and amino acids in a rat model. 2nd
The production of new protein sources is necessary to sustain the worldwide consumption. Among them, oilseed proteins are good candidates due to their good amino acid (AA) composition and the important agricultural surfaces allocated to these crops in Europa and in France, especially rapeseed and sunflower. We will study the potential of theses crops, as well as flaxseed which outlets are increasing, to provide protein of good quality for human nutrition. For this purpose, several barriers have to be knocked down. On a technological point of view, protein extraction processes are not optimized and the incorporation of oilseed proteins in consumable food is few addressed. On a nutritional point of view, there are almost no data in humans related to the quality of these proteins. Our project will address these questions in three steps connected to each other. (1) Extraction processes will be optimized to increase the extraction yield, to remove compounds that can limit their interest for food products and to lower the volumes of effluents to achieve the most sustainable process as possible. (2) Assays of food enrichment will be implemented to obtain acceptable food products that can be produced at industrial scale. (3) Protein quality in these food products will be measured in vivo in humans using a novel dual tracer method for determining AA bioavailability. This method has been proposed by a FAO committee expert but was not implemented yet and will be developed in this project. The principle is to mix in an experimental meal a standard 13C protein (such as algae) together with the intrinsically labelled oilseed proteins. The blood 15N/13C or 2H/13C ratio will be compared to the ratio of the same AA in the meal and amodification of this ratio will reflect a modification of the AA bioavailability. The project will be conducted on a multistep mode, including upstream technological work to optimize protein extraction and purification, to formulate acceptable food products and to label the plants. As a result, experimental meals incorporating the intrinsically labelled proteins will be used for bioavailability in vivo studies. This project will bring the first validation of this non-invasive method for AA bioavailability, as well as the first data on protein and AA bioavailability of oilseeds, rapeseed, sunflower and flaxseed. The consortium is complementary and brings all the expertise necessary for the project: oilseed agronomy (Terres Inovia), oilseed ingredient production (Avril), plant protein biochemistry (LRGP) and in vivo protein quality assessment (PNCA). The project will provide basic and applied integrated additional knowledge related to agriculture, food sciences, food processing and human nutrition that will support local oilseed crop and oilseed protein development and use. This project will bring new data on the sustainability of oilseed proteins and their interest in human nutrition. It will favor the emergence of new sectors for exploitation of oilseed proteins in human nutrition. ProDige will assess the economic interest of greater crop diversification, and thus the opportunities of the diversification of species for agro-industrial strategies and consumer demands. This represents an important issue since rapeseed and sunflower represent a production of 1,2 million tons of protein in France. The project will bring keys points to determine the feasibility of exploiting this already existing protein resource and of developing food products enriched in oilseed proteins in France and Europa.
Madame Claire GAUDICHON (UMR de Physiologie de la Nutrition et du Comportement Alimentaire)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
CNRS - LRGP CNRS - Laboratoire Réactions et Génie des Procédés - UMR 7274 CNRS-UL
PNCA UMR de Physiologie de la Nutrition et du Comportement Alimentaire
Help of the ANR 350,421 euros
Beginning and duration of the scientific project: November 2016 - 48 Months