Assessing changes in Cd phytoavailability to tomato in amended calcareous soils

An efficient production method of heme-iron-enriched peptide was developed based on enzymatic hydrolysis. Hemoglobin hydrolysis, carried out stepwise with commercially available exopeptidase and endopeptidase, resulted in an increased degree of hydrolysis (DH). Exopeptidase-catalyzed protein hydrolysis formed low molecular weight peptides and amino acids. Different process parameters including dialysis and ultra- and diafiltration were evaluated. Heme/peptide ratio increased as molecular weight cut-off (MWCO) of the dialysis membrane increased. When the hydrolysate was dialyzed against sodium phosphate buffer, a higher heme/ peptide ratio was obtained. The heme/peptide ratio of the hydrolysate reached up to 25.4% when the dialysis was carried out with a membrane of 12-14 kDa MWCO. Also, the ratio was improved by the use of ultrafiltration and diafiltration on the pilot-scale.