Table 4. Portal bioavailability and release half-life of XPP peptides—Effect of a protein matrix.

						p-value 1
Parameter	Matrix	Group	IPP	LPP	VPP	Matrix/Spike effect	XPP effect	Inter-action
PDV total net balance (% of intake)	Water-based	XPP	0.08±0.03	0.09±0.03	0.07±0.02	<0.0001	<0.0001	<0.0001
	protein	CasH	0.25±0.04*	0.17±0.03	5.81±0.98*	<0.0001	<0.0001	<0.0001
		CasH+XPP	0.19±0.03	0.16±0.03	0.28±0.05 #
t ½,r (min)	Water-based	XPP	11±1	16±5	18±5	<0.0001	0.921	0.556
	protein	CasH	34±4 §	32±3 §	32±5 §	0.297	0.678	0.739
		CasH+XPP	32±3	29±3	34±4

Portal bioavailability, measured as post-prandial total net release to the portal system (PDV total net balance), and time when 50% of total portal tri-peptide net release occurred (t½,r) after an intra gastric bolus administrated of the tri-peptides isoleucine-proline-proline (IPP), leucine-proline-proline (LPP), valine-proline-proline (VPP) in a water-based matrix (synthetic XPP) or in a protein matrix (casein hydrolysate rich in XPP: CasH). Values are means ± SEM; XPP: n = 8; CasH: n = 8; CasH+XPP: n = 9. Significance: p<0.05.

¹⁾: significance for comparison of water-based matrix (XPP) with protein matrix (CasH). Or significance for comparison between XPP spiked (CasH+XPP) and non-spiked protein matrix (CasH): Two-way ANOVA. When appropiate post-hoc unpaired t-test is done:

*): p<0.05 significance for comparison IPP, LPP or VPP of water-based matrix (XPP) relative to protein matrix (CasH).

^#): p<0.05 significance for comparison IPP, LPP or VPP of protein matrix (CasH) relative to spiked protein matrix (CasH+ XPP). When appropriate post-hoc Fisher’s LSD is done:

^§): p<0.05 significance for comparison IPP, LPP or VPP of waterbased matrix (XPP) relative to protein matrix (CasH).