Abstract
The antihypertensive peptides, Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP), were first isolated from Lactobacillus helveticus fermented milk; however, there are few reports on the antihypertensive effects of cheese. The objective of this study was to quantify the amounts of VPP and IPP in various cheeses and to discuss the potential of these antihypertensive effects. Fifteen European-type cheeses were selected and analyzed for these two antihypertensive peptides using an LC-MS analysis. The Dutch cheeses, Reypenaer and Old Amsterdam, contained high amounts of VPP/IPP, 19.9/0.9 and 10.5/0.9 mg in 100 g of cheese, respectively. The Swiss cheeses, Emmental and Gruyere, also contained VPP/IPP at 8.0/1.1 and 5.2/1.2 mg in 100 g of cheese, respectively. Notably, some French-type Blue cheeses prepared with Penicillium roqueforti contained the highest amounts of both peptides (13.3/31.0 mg in Bleu d'Auvergne and 9.9/19.2 mg in Bleu des Causses in 100 g of cheese). The ratio of VPP to IPP was higher in Dutch and Swiss cheeses than in Blue cheeses. To understand the release of these peptides in Blue cheese, proteolytic enzymes, neutral protease I (NPI) and leucine amino peptidase (LAP), previously identified as crucial proteolytic enzymes for IPP processing in Aspergillus oryzae, were searched in Penicillium using BLAST. A homolog with similarity to NPI of A. oryzae was detected in extracellular metalloproteinase-4 of Penicillium subrubescens with 36% identity. Moreover, LAP of A. oryzae was identical to an unknown protein of P. roqueforti. These observations suggest that proteases of Penicillium with homology to A. oryzae NPI and LAP might be involved in the processing of antihypertensive peptides during Blue cheese ripening.
