How Cooking Time Affects In Vitro Starch and Protein Digestibility of Whole Cooked Lentil Seeds versus Isolated Cotyledon Cells

Abstract

Lentils are sustainable sources of bioencapsulated macronutrients, meaning physical barriers hinder the permeation of digestive enzymes into cotyledon cells, slowing down macronutrient digestion. While lentils are typically consumed as cooked seeds, insights into the effect of cooking time on microstructural and related digestive properties are lacking. Therefore, the effect of cooking time (15, 30, or 60 min) on in vitro amylolysis and proteolysis kinetics of lentil seeds (CL) and an important microstructural fraction, i.e., cotyledon cells isolated thereof (ICC), were studied. For ICC, cooking time had no significant effect on amylolysis kinetics, while small but significant differences in proteolysis were observed (p < 0.05). In contrast, cooking time importantly affected the microstructure obtained upon the mechanical disintegration of whole lentils, resulting in significantly different digestion kinetics. Upon long cooking times (60 min), digestion kinetics approached those of ICC since mechanical disintegration yielded a high fraction of individual cotyledon cells (67 g/100 g dry matter). However, cooked lentils with a short cooking time (15 min) showed significantly slower amylolysis with a lower final extent (~30%), due to the presence of more cell clusters upon disintegration. In conclusion, cooking time can be used to obtain distinct microstructures and digestive functionalities with perspectives for household and industrial preparation.

From static to semi-dynamic in vitro digestion conditions relevant for the older population: starch and protein digestion of cooked lentils

“…While this implies that exact digestion extents quantified based on DNS analysis should be interpreted cautiously and different starch metabolites can be better quantified using e.g., chromatographic methods, 61 the DNS method does give valuable insight into amylolysis trends and can allow the comparison of overall digestion trends. 32 To conclude, the incorporation of saliva and the applied digestion model (healthy versus older adult) did significantly affect gastric and subsequent small intestinal kinetics of amylolysis, though similar final (small intestinal) levels were obtained. For both considered food products, gastric digestion at higher pH levels (older adult conditions) lead to a higher degree of amylolysis by the end of gastric digestion.…”

“…Raw lentils were soaked, then cooked to palatable texture for 30 min at 95 °C, in similarity to a previous study. 32 White bread was obtained from the local supermarket and utilized as provided.…”

“…Regarding the microstructure, particle size distributions (PSDs) of cooked lentils, mixed at low speed in SSF were shown to largely overlap with PSDs of cooked beans upon in vivo mastication in previous work. 19,32 Therefore, lentils and white bread were mixed into standardized purees using an Ultraturrax mixer (3000 rpm).…”

“…Digested starch was quantified spectrophotometrically using the dinitrosalicylic (DNS) method, employing a maltose calibration curve (0.5-2.0 mg mL −1 ), exactly as described earlier. 32…”

Processed foods: From their emergence to resilient technologies

“…PEF treatments have also been shown to aid the inactivation of pectinmethylesterase in tomato juice with significant viscosity enhancement and retaining/improving health‐related compounds and antioxidant capacity in tomato juices (Jayathunge et al., 2019; Odriozola‐Serrano et al., 2016). Cooking times of lentil seeds have been shown to have distinct effects on their microstructure and digestibility (Duijsens et al., 2023), and cycloartenyl ferulate was identified as the predominant compound in brown rice with potential against oxidative stress‐induced cytotoxicity (Wu et al., 2023). PEF peeling (2 kJ/kg), replacing conventional lye or steam peeling, is another example for resource conservation via appropriate technologies.…”