Therefore, this is an important index to evaluate the behaviour of coagulants during cheese ripening. It can be seen that there was an increase of pH 4.6-SN for both processes, which agrees with the literature (McSweeney & Fox, 1997). Increase of NS-pH 4.6/TN*100 during
ripening of Prato cheese this website was also reported by Garcia et al., 2009 and Gorostiza et al., 2004. Fig. 1B shows the evolution of NS-TCA 12%/TN*100, which is represented by the presence of peptides of low molecular mass and free amino acids that were produced by the action of peptidases from the starter and non starter bacteria on peptides with high/intermediate molecular mass (Fox, 1989 and Singh et al., 2003). It can be seen that there was an increase of TCA 12%-SN for both processes. Increase of NS-TCA 12%/TN*100 during ripening of Prato cheese was also reported by Garcia et al., 2009 and Gorostiza et al., 2004. According to the results from F-test of ANOVA, shown in Table 2, ripening period significantly
affected ripening indices (p < 0.01), which was expected since for ripening to occur these indices need to increase throughout time. It can also be seen that the treatments did not significantly affect NS-pH 4.6/TN*100 suggesting that coagulant from T. indicae-seudaticae N31 caused the same type of proteolysis as commercial coagulant. However, treatments affected NS-TCA 12%/TN*100 (p < 0.05) but when carrying out comparison of means by Tukey test, no differences were revealed between treatments. Also, the interaction between treatments and ripening period
did not significantly affect the indices, indicating that proteolysis increases throughout ripening http://www.selleckchem.com/products/BMS-777607.html in the same way for cheeses made with commercial coagulant and with coagulant from T. indicae-seudaticae N31. Residual chymosin rapidly hydrolyses αs1-casein at the bond Phe23–Phe24 during initial O-methylated flavonoid stages of ripening, resulting in the formation of a large peptide αs1-CN f24–199 (αs1-I-casein) and the small one αs1-CN f1–23. Hydrolysis of this bond causes a rapid change in the rubbery texture of Cheddar cheese into a more homogenous and smoother product (Lawrence et al., 1987 and Singh et al., 2003). Since the NS-pH 4.6/TN*100 evolution was not significantly different for cheeses produced with each coagulant, a similar αs1-casein hydrolysis profile was expected for these cheeses, however this was not observed as seen in Fig. 2B as explained earlier by the different action of the coagulants due to ripening pH and temperature. Plasmin acts on β-casein resulting on the formation of three γ-caseins [γ1-(β-CN f29–209), γ2-(β-CN f106–209) and γ3-(β-CN f108–209)], representing the C-terminal region and of five proteose–peptones, representing the N-terminal region (Singh et al., 2003). These proteose–peptones are soluble at pH 4.6 affecting pH 4.6-SN, although their contribution is small (McSweeney & Fox, 1997). According to Singh et al.