Effects of chromatographically pure bovine chymosin and pepsin A on cheese curd firmness

Abstract

SummaryThe effects of chromatographically pure bovine chymosin and pepsin A on cheese curd firmness have been investigated. The enzymes were studied in parallel experiments, using a Formagraph, under which the following parameters were tested and varied: reconstituted skim milk powder, bulk raw milk, CaCl2 addition, enzyme concentration and temperature. Chymosin had a slightly better rate of curd firming (P ≤ 0·001) and better curd firmness 30 min after gelling point compared to pepsin under all of the conditions investigated. However, as regards curd firmness in cheese manufacture, this difference is only a question of time, since pepsin will give the same degree of curd firmness of the cheesemilk as chymosin after some minutes. The biggest disadvantage with pepsin is its strong pH dependence, which can lead to very long gelling times and weak curd if the pH is too high and the rennet is dominated by pepsin.