244 Comparative crude protein solubilization in yellow pea and fava bean protein concentrates in a simulated porcine gastric and intestinal digestion model

Abstract

Abstract Pulses are valuable protein ingredients but unique characteristics among them are known to influence protein quality and utilization. We determined crude protein solubilization (CPS) in yellow pea (YP) and fava bean (FB) protein concentrates using simulated porcine gastric and intestinal model (Table 1). For each ingredient, 500 mg CP equivalent was incubated in triplicate with pepsin at either pH 3.5 or 4.5 for 0, 0.5, 1, and 1.5 h at 39°C and 200 r.p.m. for gastric CPS. For intestinal CPS, gastric samples (derived at pH 3.5 for 1.5 h) were incubated with pancreatin and bile extract at pH 6.8 for 0, 0.5, 2, 4 and 6 h. Intestinal CPS was categorized as CPfast, CPslow and CPresistant corresponding to CPS within the first 0.5 h, 0.5 to 4 h, and undigested after 4 h, respectively (Table 2). The concentration of CP in the supernatant was equated to CPS. Data were subjected to Proc GLIMIXX of SAS while Gompertz equation was used to describe the gastric and intestinal solubilization kinetics (A-maximum solubilized CP, Wo- initial CP solubility, Ku- solubilization rate, Ti- time to inflection). The model for gastric CPS had fixed effects of protein, incubation time, stomach pH and their interaction at 1.5 h and while fixed effects of protein was evaluated in intestinal CPS kinetics. The analyzed CP in FB and YP were 712.7 and 599.1, g/kg DM, with 3 and 4% of CP bound to NDF, respectively. Gastric CPS in FB was not influenced (P > 0.05) by pH and incubation time; however, at 1.5 h gastric CPS in FB was 40.9 and 28.44% at pH 3.5 and 4.5, respectively. Gastric CPS in YP was influenced by incubation time (P < 0.05) with increase at pH 3.5 after 1 h and at pH 4.5 after 0.5 h compared with 0 h. After 1.5 h, gastric CPS in YP was 50.0% at pH 3.5 and 33.2% at pH 4.5. Whereas YP gastric CPS at pH 3.5 and 1.5h was greater compared with FB, there were no differences (P > 0.05) between the FB and TP at pH 4.5. However, intestinal CPS tended (P < 0.10) to be greater for FB (91.7%) compared with YP (89.4%). The FP was solubilized faster (Ku; P < 0.05) than YP, supported by a (P < 0.05) higher CPfast of FB (87.8%) compared with YP (75.9%). CPresistent was found to be greater (P < 0.05) for YP (12.0%) than for FB (6.6%; Figure 1). In conclusion, fava, and pea protein concentrates had gastric protein solubilization that was dependent on pH. The less resistant protein in FB suggested a greater nutritive value than YP. Further research should determine ileal amino acids digestibility and the impact of incorporation in practical diets to characterize animal performance, health, and environment impact.