In Vitro Digestibility of Rapeseed and Bovine Whey Protein Mixtures

Abstract

Partial replacement of animal protein sources with plant proteins is highly relevant for the food industry, but potential effects on protein digestibility need to be established. In this study, the in vitro protein digestibility (IVPD) of four protein sources and their mixtures (50:50 w/w ratio) was investigated using a transient pepsin hydrolysis (1 h) followed by pancreatin (1 h). The protein sources consisted of napin-rich rapeseed (Brassica napus L.) protein concentrates (RPCs; RP1, RP2) prepared in pilot scale and major bovine whey proteins (WPs; α-LA, alpha-lactalbumin; β-LG, beta-lactoglobulin). IVPD of individual protein sources was higher for WPs compared to RPCs. The RP2/β-LG mixture resulted in an unexpected high IVPD equivalent to β-LG protein alone. Protein mixtures containing RP1 showed a new IVPD response type due to the negative influence of a high trypsin inhibitor activity (TIA) level. Improved IVPD of RP1 alone and in protein mixtures was obtained by lowering the TIA level using dithiothreitol (DTT). These results showed that napin-rich protein products prepared by appropriate processing can be combined with specific WPs in mixtures to improve the IVPD.

Comparison of Faba Bean Protein Ingredients Produced Using Dry Fractionation and Isoelectric Precipitation: Techno-Functional, Nutritional and Environmental Performance

“…Gastro-pancreatic protein digestion was simulated using a multistage static in vitro protein digestibility (IVPD) method, as described previously [24,25]. In addition to FPR and FPI, a faba bean dehulled flour (FDH) from the same faba bean source was also analyzed for comparison.…”

“…The two supernatants were pooled, kept in the refrigerator overnight, and centrifuged again for 5 min at 3000× g prior to TIA analysis. TIA levels of the faba bean ingredients were determined using a previously described method, with a few modifications [25]. In short, the TIA levels were determined against a trypsin enzyme solution with a stock concentration of 0.1 mg/mL.…”

Techno-Functional, Nutritional and Environmental Performance of Protein Isolates from Blue Lupin and White Lupin

“…Simulated gastro-intestinal protein digestion was performed using a multistage, static in vitro protein digestibility (IVPD) method, according to previous descriptions [36,37]. In short, LPI samples were initially weighed to contain 50 ± 0.1 mg protein on dry matter basis.…”

“…Enzyme to substrate (E:S) ratios applied during the stages of pepsin and pancreatin digestion were kept constant at 1:50 and 1:10 w/w, respectively. IVPD % was determined using a trinitrobenzenesulfonic acid (TNBS)-based quantification method, applying an alanine standard solution representing 100% protein digestibility at each stage of digestion [36].…”

“…The supernatants were pooled, maintained at 4 • C overnight, and centrifuged again at 3000× g for 5 min before analysis of TIA. TIA levels of the LPI were measured, with a few modifications, according to a previously described method [36]. Briefly, the TIA levels were determined against a solution of purified trypsin enzyme with a stock concentration of 0.1 mg/mL.…”