Process for the treatment of green, leafy plants for the extraction of proteins in the pressing juices and for economical dehydration of cake

An integrated process for the treatment of leafy green vegetable matter, comprising the steps of:

• 1. Treating a portion of the fresh vegetable matter in a strongly alkaline liquid medium and at a moderate temperature, said conditions permitting solubilization of the cytoplasmic proteins in the liquid reaction medium and flocculation of the pigmented proteins within the vegetable tissues;
• 2. Pressing the hot medium obtained in step (1) and separating a brown juice and a first cake;
• 3. Thermal treatment of said first cake in a liquid medium, the temperature being in the range of 80.degree. to 90.degree. C;
• 4. second pressing of the hot cake treated in (3), this producing a second cake and a serum, the said cake being suited to dehydration and conversion into agglomerated pellets,
• 5. Treatment of the brown juice obtained after the first pressing (step (2) ) by the addition of an acid capable of adjusting the pH of said juice to between 7.0 and 7.5, this inducing a flocculation of the pigmented proteins present, in a small amount, in the said juice, and separating a green protein cream and a liquid effluent referred to as the pigmented brown juice;
• 6. Concentrating the green protein cream separated in step (5) and/or recycling the said green cream to add it to the second pressing cake obtained in step (4);
• 7. Treating the depigmented brown juice to separate the white cytoplasmic proteins contained therein, the said flocculation being realized by the thermal way (for example, by heating between 70.degree. and 95.degree. C, notably at 85.degree. C) or by the acid way, by the addition of at least one acid capable of adjusting the pH of the brown juice to between 3 and 6, the said treatment providing, after separation, a white cream and a serum;
• 8. Further treatment of the white cream by purification and drying to obtain a white protein concentrate;
• 9. Treatment of the respective sera obtained from the second pressing (step (4)) and step (7), the said sera having been collected together and then clarified, one portion of the clarified serum being concentrated, while the residual portion is recycled to steps (1) and (3) to act as the liquid medium and as vector of calories, the recycled serum being, for this purpose, reheated and/or having an alkaline agent such as sodium hydroxide added thereto;
• 10. Cold pressing the portion of the fresh vegetable matter not subjected to the treatment of step (1), providing a high-protein green juice and a third cake, which are separated;
• 11. Adding said third cake to the first cake, obtained in step (2), for then to undergo the treatment of step (3) together;
• 12. Further treatment of the green juice to flocculate all the pigmented and cytoplasmic proteins contained in said juice, the said treatment involving successively an alkalinization treatment to a pH of about 8.5, for example by the addition of ammonia, a thermal treatment inducing flocculation of the proteins, separating the protein precipitate and the serum, and conditioning the green cream separated to obtain a green protein concentrate;
• 13. Recovery of the serum separated in step (12) and its use in step (9).