In vitro macronutrient digestibility and mineral bioaccessibility of lentil-based pasta: The influence of cellular intactness.

Recently, pulse ingredients with (partial) cellular intactness are put forward as promising innovative food ingredients with slowed macronutrient digestibility. This study compared cooking quality and nutrient (starch, protein, and mineral) digestibility/bioaccessibility of lentil-based pasta prepared from 100% raw-milled flour, and by substituting 30% of the formulation by isolated cotyledon cell powder or whole precooked powder. Formulation had little effect on cooking properties. Both amylolysis and proteolysis were significantly slowed by incorporating cellular ingredients: towards the end of simulated digestion, amylolysis was lowered by 16-25%, while differences in proteolysis became small. Cellular ingredient incorporation slightly decreased Zn and Mg but did not affect Ca and Fe bioaccessibility, overall yielding a low mineral bioaccessibility comparable to cooked whole pulses. To conclude, lentil-based pasta substituted with cellular ingredients showed improved nutritional properties (i.e., high in digestible protein and slowed amylolysis), with perspectives for the development of different innovative foods with targeted nutritional properties.

Effect of manufacturing conditions on in vitro starch and protein digestibility of (cellular) lentil-based ingredients.

(Cellular) pulse powders are being proposed as ingredients for different foods. However, the effect of manufacturing conditions on the properties of those powders remained unknown. Therefore, this study investigated the effect of specific manufacturing conditions (cooking time, application of cell isolation, and drying method) on the composition, microstructure, and in vitro starch and protein digestibility of lentil powders. Next to powders consisting of isolated cotyledon cells (ICC), this study proposes the production of precooked whole lentil powders (WL), without a cellular isolation step. In a model food system (heat-treated suspension), starch and protein digestion were significantly attenuated for both WL and ICC compared to raw-milled lentil flour. The applied cooking time determined macronutrient digestibility in the powders by (i) affecting the susceptibility of ICC to in vitro digestion, and (ii) determining the microstructural properties of WL. Freeze-dried ICC powder showed a stronger attenuation of amylolysis compared air-dried ICC. This study showed that WL powders have an important potential as innovative food ingredients higher in fiber but lower in starch compared to ICC.

Studying semi-dynamic digestion kinetics of food: Establishing a computer-controlled multireactor approach.

In this work, a multireactor system to study digestion (MuReDi) kinetics is introduced. For this, a custom-made automated system with four independent syringe pumps (BioXplorer 100, H.E.L Group) was acquired. This system consists of multiple, small-scale reactors allowing to study digestion as a function of time and thus to determine digestion kinetics. The different digestion conditions used in the oral, gastric, and small intestinal phase were based on the digestion protocols published by the INFOGEST consortium. We showed that the minimum working volume of a reactor is 30 mL. Besides, repeatability of the digestion kinetics was shown for two food systems: a liquid Ensure® Plus Vanilla drink, and a solid, cooked lentil sample. When comparing static digestion kinetics with semi-dynamic ones, a significantly different digestion pattern was observed. In the static case, a relatively fast hydrolysis rate was observed until a clear plateau was reached. Oppositely, for the semi-dynamic case, a delayed start of the hydrolysis process was noticed. In the gastric phase, this was explained by the decreasing pH and the large pH dependency of pepsin activity. In the small intestine, the lag phase was relatively shorter, yet clearly present. Here we related it to the gradual enzyme (and bile salt) secretion that had to diffuse towards the substrate before hydrolysis could start. Generally, this work showed that the MuReDi system could be used to perform a semi-dynamic digestion approach which largely impacted the overall digestion kinetics. This is important to consider in future in vitro food digestion simulation work to come closer to physiologically relevant digestion kinetics.