Peptide composition and dipeptidyl peptidase IV inhibitory properties of β-lactoglobulin hydrolysates having similar extents of hydrolysis while generated using different enzyme-to-substrate ratios

- β-Lactoglobulin was hydrolysed using three enzyme-to-substrate ratios (E:S).
- Hydrolyses were carried out to reach degrees of hydrolysis (DH) of 9 and 13%.
- Molecular mass distribution was independent of the E:S
- Dipeptidyl peptidase IV (DPP-IV) inhibitory activity was independent of the E:S.
- The majority of peptides sequenced were common in samples having similar DHs.

β-Lactoglobulin hydrolysates (βlgHs) were generated using elastase at enzyme-to-substrate ratios (E:S) of 0.5, 1.0 and 1.5% in order to reach target degree of hydrolysis (DH) values of 9 and 13%. The impact of different E:S during manufacture on hydrolysates having similar DHs was assessed. Samples with similar DHs generated with different E:S showed comparable molecular mass distribution profiles and in vitro dipeptidyl peptidase IV (DPP-IV) inhibitory activities (p > 0.05). Liquid-chromatography tandem mass spectrometry (LC-MS/MS) analysis showed that 62 and 84% of the peptides identified were common within hydrolysates having a similar DH of 9 or 13%, respectively. Differences in the peptides identified within hydrolysates having similar DHs may be due to E:S dependent modifications in specificity and enzyme kinetics. Overall, this study showed that reduction in E:S while targeting the development of a similar DH for βlgHs may be employed to reduce the cost of hydrolysate production without having an adverse impact on the bioactivity and physicochemical properties studied herein.

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