Sunflower protein hydrolysates for dietary treatment of patients with liver failure

A method is described to obtain hydrolysates with defined characteristics and a high Fischer ratio for patients with liver failure, using sunflower proteins (globulin fraction‐II) as starting material. Protein with a branched chain amino acid (BCAA) concentration of 29.7±1.7% is treated in a first step with immobilized chymotrypsin (raw hydrolysate‐1). Subsequent ultrafiltration (cut‐off 3 kDa) of the hydrolysate gives sunflower protein hydrolysate‐I (SFPH‐I). In a second step, SFPH‐I is treated with immobilized carboxypeptidase‐A at alkaline pH for quasi‐selective removal of aromatic amino acids (AAA). This sequential two‐step process, followed by size exclusion chromatography on a Sephadex G‐15 column, yields a product (SFPH‐II) with a BCAA concentration of 37.4±2.2% and an AAA concentration of 0.5±0.1%, which gives a very high Fischer ratio (≈75). The product, comprising mainly peptides with molecular weights in the range of 3500 to 750 Da and free amino acids, is hypoallergenic and shows no or only a trace of bitterness. Any bitterness can be completely removed by treatment with Flavozyme®, giving a hydrolysate that is composed mainly by tri‐ and dipeptides and free amino acids, and is termed highly hydrolyzed protein hydrolysate (HHPH). Both SFPH‐II and HHPH can be used in enteral, parenteral, and oral nutrition for the treatment of patients with liver failure. This product presents all the conditions required for use in the treatment of patients with liver failure: high content in BCAA and low content in AAA, below 2%, and consequently, a very high Fischer ratio, ≈75.