Dipeptidyl Peptidase IV Inhibitory Peptides Generated in Dry-Cured Pork Loin during Aging and Gastrointestinal Digestion

Abstract

The ability of peptides from an aqueous and salt-soluble protein extract of dry-cured pork loins to inhibit the action of dipeptidyl peptidase IV was determined. This activity was assessed at different times of the production process, i.e., 28, 90, 180, 270 and 360 days. The resistance of the biological property during the simulated digestive process was also assessed. For this, the extracts were hydrolyzed with pepsin and pancreatin as a simulated digestion step of the gastrointestinal tract and fractionated (>7 kDa) as an intestinal absorption step. The results indicate that dried-pork-loin peptides may have potential as functional food ingredients in the prevention and treatment of type 2 diabetes mellitus. In particular, the APPPPAEV, APPPPAEVH, KLPPLPL, RLPLLP, VATPPPPPPK, VPIPVPLPM and VPLPVPVPI sequences show promise as natural food compounds helpful in maintaining good health.

Keywords: LAB; bioactive peptides; dipeptidyl peptidase IV (DPP-IV); dry-cured loin.

Figure 1

Dendrogram resulting from the Ward’s method of hierarchical cluster analysis of peptides (>7 kDa)concentration (mg/mL) and DPP-IV-inhibiting activity (%) in analyzed fractions WSF, water-soluble fraction; SSF, salt-soluble fraction; C, control sample; LOCK, sample inoculated with Lactobacillus rhamnosus LOCK900; BAUER, sample inoculated with Lactobacillus acidophilus Bauer Ł0938; BB12, sample inoculated with Bifidobacterium animalis ssp. lactis BB-12.

Figure 2

Correlation (Pearson’s correlation coefficient) between peptides content and DPP-IV-inhibiting activity of the tested samples. WSF, water-soluble fraction; SSF, salt-soluble fraction; C, control sample; LOCK, sample inoculated with Lactobacillus rhamnosus LOCK900; BAUER, sample inoculated with Lactobacillus acidophilus Bauer Ł0938; BB12, sample inoculated with Bifidobacterium animalis ssp. lactis BB-12.

Figure 3

Venn diagram showing number of peptides obtained after SDIG of dry-curedpork loin after 180 days of ageing. WSF, water-soluble fraction; SSF, salt-soluble fraction; C, control sample; LOCK, sample inoculated with Lactobacillus rhamnosus LOCK900; BAUER, sample inoculated with Lactobacillus acidophilus Bauer Ł0938; BB12, sample inoculated with Bifidobacterium animalis ssp. lactis BB-12).

Figure 4

Three-dimensional molecular docking results of the receptor–ligand (peptide) systems in both surface representation (A) and cartoon-ribbon representation (B).