Gastrointestinal Digestion Of Proteins Research Articles

Evaluation of Proprietary MDZenPro Formulation by Zenherb Labs in Mediating Protein Digestion under INFOGEST in-vitro Simulated Gastrointestinal Conditions

Protein breakdown by endogenous enzymes in the gastrointestinal (GI) tract results in generation of peptides and amino acids that act as building blocks in essential biological functions. Exogenous proteases possess immense potential as digestive enzyme supplements that can assist protein digestion in the GI system. Plant proteases, in addition to their promising activity, are considered to be safe in nature. The present study evaluated the potential application of a plant protease based proprietary formulation - MDZenPro in digesting raw whey protein, whey protein isolate and plant protein under INFOGEST simulated GI conditions. The gastric and GI digested protein products were analyzed for determining the degree of hydrolysis. The protein profiles were evaluated using SDS-PAGE. The results of the degree of hydrolysis study revealed that MDZenPro facilitated gastric and GI digestion of proteins. This increase in degree of hydrolysis was noted to be higher than that observed in proteins that were not treated with MDZenPro. The SDS-PAGE profile further supported these findings wherein, the MDZenPro treated protein samples displayed low molecular weight fragmented peptides in contrast to the profile of undigested proteins. The present study thus highlights the promising application of ‘MDZenPro’ as an effective supplement for protein digestion.

In vitro gastrointestinal digestion of proteins in the presence of enzyme supplements: Details of antioxidant and antidiabetic properties

Athletes tend to consume more protein than the daily recommended allowance due to their high energy demanding lifestyle. It is worthwhile to supplement their proteins with external enzymes to increase the bioavailability. We have designed in vitro study of two commercial plant proteases (SEBproX and SEBrolase) and one microbial enzyme formulation (pepzymeAG) to determine their role in digestion and absorption of protein. The study was done under INFOGEST simulated GI conditions using pea, whey, and collagen proteins. Increment in degree of hydrolysis was observed in pepzymeAG assisted digestion and SEBproX assisted digestion as opposed to that of SEBrolase assisted digestion of proteins. Further, bioactive peptides with enhanced antioxidant and antidiabetic properties were found to be released in only pepzymeAG assisted digestion. Lower molecular weight peptides (≤6 kDa) were observed to be generated in the gastric digestion stage of pepzymeAG assisted digestion which may increases the rate of gastric emptying and hence helps in better absorption of protein through the intestine. Overall, pepzymeAG could be a great choice for athletes to get benefits of proteins beyond their common nutritional goals.

Glucagon-like peptide-1 regulation by food proteins and protein hydrolysates.

Glucagon-like peptide-1 (GLP-1) is an enterohormone with a key role in several processes controlling body homeostasis, including glucose homeostasis and food intake regulation. It is secreted by the intestinal cells in response to nutrients, such as glucose, fat and amino acids. In the present review, we analyse the effect of protein on GLP-1 secretion and clearance. We review the literature on the GLP-1 secretory effects of protein and protein hydrolysates, and the mechanisms through which they exert these effects. We also review the studies on protein from different sources that has inhibitory effects on dipeptidyl peptidase-4 (DPP4), the enzyme responsible for GLP-1 inactivation, with particular emphasis on specific sources and treatments, and the gaps there still are in knowledge. There is evidence that the protein source and the hydrolytic processing applied to them can influence the effects on GLP-1 signalling. The gastrointestinal digestion of proteins, for example, significantly changes their effectiveness at modulating this enterohormone secretion in both in vivo and in vitro studies. Nevertheless, little information is available regarding human studies and more research is required to understand their potential as regulators of glucose homeostasis.

Cooking does not impair the impact of pulsed electric field on the protein digestion of venison (Cervus elaphus) during in vitro gastrointestinal digestion

SummaryThe present study was conducted to elucidate whether cooking impairs the positive effect of pulsed electric field (PEF) on the digestibility of venison during in vitro gastrointestinal protein digestion. Previous studies have used fresh uncooked meat to demonstrate the effect of PEF on protein digestibility during gastrointestinal digestion neglecting the effect that cooking could induce during meat preparation process. PEF‐treated samples (T1, 10 kV, 90 Hz, 20 µs) were cooked (core temperature of 75 °C) and subjected to in vitro simulated gastrointestinal protein digestion along with non‐treated controls. A 3% increase of in vitro protein digestibility was found in cooked PEF‐treated venison (P < 0.05). A positive (P < 0.05) impact of PEF processing was observed on overall protein digestion as measured by soluble protein (%) and SDS‐PAGE. PEF did not change (P > 0.05) the release of minerals from cooked venison during digestion. Cooking had no negative influence on the mechanism through which PEF operates in improving the protein digestibility of venison.

Sous-vide cooking improves the quality and in-vitro digestibility of Semitendinosus from culled dairy cows.

Effect of sous-vide processing was evaluated on in-vitro simulated protein digestion, myofibrillar protein profile, lipid oxidation and physicochemical properties of cold-boned beef Semitendinosus. Sous-vide processed [T1, 60 °C (4.5 h); T2, 60 °C (10 h)] samples along with control beef (cooked at 80 °C until a core temperature of 75 °C was attained) were subjected to in-vitro simulated gastrointestinal protein digestion. Samples collected at 0, 30 and 60 min of gastric digestion and 120 and 180 min of intestinal digestion were analysed for protein profile (SDS-PAGE), protein digestibility (%), soluble protein (%), free amino acid analysis and mineral profile. A significant (P < 0.05) decrease was observed in shear force (N) and cooking loss (%) of sous-vide processed samples in comparison to control whereas a significant (P < 0.05) increase was observed in colour (L*, a*, b*). A significant (P < 0.05) increase was also observed in protein digestibility (%), soluble protein (%) and release of free amino acids and minerals from sous-vide processed samples during in-vitro digestion. By modifying the protein profile of the meat, sous-vide processing had a positive influence on in-vitro digestion kinetics that led to a greater and faster digestion of proteins during simulated digestion.

Comparative efficacy of actinidin from green and gold kiwi fruit extract on in vitro simulated protein digestion of beef Semitendinosus and its myofibrillar protein fraction

SummaryThis study was conducted to evaluate the comparative efficacy of actinidin from green and gold kiwifruit extract on in vitro simulated gastrointestinal protein digestion of cooked beef Semitendinosus and its myofibrillar protein fraction. Samples collected during gastrointestinal digestion were analysed for protein profile, protein digestibility (%), soluble protein (%) and free amino acid analysis. The addition of kiwifruit extracts significantly (P &lt; 0.05) increased protein digestibility, soluble protein and free amino acids released during in vitro gastrointestinal digestion. The in vitro digestibility (%) of the meat samples digested along the green or the gold kiwifruit extract was 2.08% and 3.47% higher than control samples respectively. The soluble protein (%) of the meat samples digested along the green kiwifruit extract was significantly (P &lt; 0.05) higher (18.28%) than control samples (13.03%) after gastrointestinal digestion. Comparatively, actinidin from green kiwifruit extract was more effective than gold kiwifruit extract.

Pulsed electric field: A new way to improve digestibility of cooked beef

The effect of pulsed electric field (PEF) on in-vitro simulated gastrointestinal protein digestion of cooked beef Semimembranosus was elucidated. PEF treated (T1, 10 kV, 20 Hz, 20 μs) samples along with control were cooked (core temperature of 75 °C) and subjected to in-vitro simulated gastrointestinal digestion. Samples were analysed for protein digestibility (%), protein profile (SDS-PAGE), soluble protein (%), free amino acid analysis and mineral profile. PEF treatment led to significantly higher (P < .05) values for protein digestibility (%) and soluble protein (%). No significant (P > .05) effect of PEF was recorded on the release of free amino acids and various minerals during gastrointestinal digestion. PEF treatment modified the protein profile of the meat digests and had a positive impact on in-vitro digestion kinetics causing greater and faster digestion of proteins during in-vitro gastrointestinal simulation.

Pulsed electric field improved protein digestion of beef during in-vitro gastrointestinal simulation

Effect of pulsed electric field (PEF) on in-vitro simulated gastrointestinal protein digestion of cold-boned beef Semimembranosus was elucidated. PEF treated [T1, 5.0 kV (90 Hz); T2, 10 kV (20 Hz)] samples along with control were subjected to in-vitro simulated gastrointestinal protein digestion. Samples collected at 0, 30 and 60 min of gastric digestion and 120 and 180 min of intestinal digestion were analysed for protein digestibility (%), soluble protein (%), protein profile (SDS-PAGE), free amino acid analysis and mineral profile. Significantly higher (P < 0.05) protein digestibility (%) and soluble protein (%) values were observed for PEF treated samples. No negative impact (P > 0.05) of PEF was observed on the release of various minerals from the muscle during the digestion. By modifying the protein profile of the meat digests, PEF processing had a positive influence on in-vitro digestion kinetics that led to a faster and greater digestion of proteins during simulated gastrointestinal digestion.

Pulsed electric field: Effect on in-vitro simulated gastrointestinal protein digestion of deer Longissimus dorsi

The effect of pulsed electric field (PEF) on in-vitro simulated gastrointestinal protein digestion of cold-boned deer Longissimus dorsi was elucidated. PEF treated samples viz. T1 (2.5 kV, 50 Hz) and T2 (10 kV, 90 Hz) along with a control were subjected to in-vitro simulated gastrointestinal protein digestion. Samples were collected after 0, 30, and 60 min of gastric digestion and 120 and 180 min of intestinal digestion. A significant (P < 0.05) increase was observed in the protein digestibility and soluble protein (%) of PEF treated samples, highlighting a positive influence of PEF processing on the digestion process. Higher concentrations of almost all the free amino acids were observed for the PEF treated samples. No significant effect of PEF was observed on the release of various minerals. PEF may be utilized for the development of novel muscle foods with improved protein digestibility.

Adducts formed during protein digestion decreased the toxicity of five carbonyl compounds against Caco-2 cells.

Acrolein (ACR), glyoxal (GO), methylglyoxal (MGO), hydroxymethylfurfural (HMF), and malondialdehyde (MDA) are toxic contaminants for humans. This work aimed to investigate whether intake of proteins can mitigate their toxicity. Simulated gastrointestinal digestion of proteins from pork, chicken, milk powder and soy protein isolate eliminated amount of ACR, GO, MGO, HMF, and MDA. Among six amino acids, cysteine showed highest capacity for elimination of these toxic compounds through the formation of adducts; it reached the highest elimination capacity for GO, MGO, ACR, MDA, and HMF in 40 min at pH 2.0, and 20 min at pH 7.0. The formed adducts between cysteine and GO, MGO, or ACR showed much lower toxicity against Caco-2 cells. Incubation of the cells with 8 mM GO and MGO for 48 h decreased the cell viability to 16.1%, 16.9% respectively; while incubation of the same concentration of their adducts still kept the cell viability at 82.2% and 81.6% respectively. Cysteine showed much higher detoxifying capacity for ACR than GO and MGO, which can lower the toxicity of ACR toward Caco-2 cells by 80 times.

Ex vivo digestion of raw, pasteurised and homogenised milk – Effects on lipolysis and proteolysis

This study investigated the impact of pasteurisation and homogenisation on ex vivo gastrointestinal digestion of proteins and fat in bovine milk. Milk that was homogenised at 150 bar showed the highest degree of lipolysis (78%) after 120 min duodenal digestion. In comparison, milk homogenised at 50 bar showed 56% release of fatty acids whereas raw and pasteurised milk showed 49% and 44% hydrolysis, respectively. Pasteurisation had very much less effect upon lipolysis and proteolysis. Homogenisation increased the gastric proteolysis of specifically β-lactoglobulin, and also of α-lactalbumin. However, after 5 min duodenal digestion all the proteins were degraded in all milks tested. Thus, both lipolysis and proteolysis were increased by homogenisation of the milk, making fatty acids from lipids and peptides from β-lactoglobulin more readily available to the human body.

Recent trends in the analysis of bioactive peptides in milk and dairy products.

Food-derived constituents represent important sources of several classes of bioactive compounds. Among them peptides have gained great attention in the last two decades thanks to the scientific evidence of their beneficial effects on health in addition to their established nutritional value. Several functionalities for bioactive peptides have been described, including antioxidative, antihypertensive, anti-inflammatory, immunomodulatory, and antimicrobial activity. They are now considered as novel and potential dietary ingredients to promote human health, though in some cases they may also have detrimental effects on health. Bioactive peptides can be naturally occurring, produced in vitro by enzymatic hydrolysis, and formed in vivo during gastrointestinal digestion of proteins. Thus, the need to gain a better understanding of the positive health effects of food peptides has prompted the development of analytical strategies for their isolation, separation, and identification in complex food matrices. Dairy products and milk are potential sources of bioactive peptides: several of them possess extra-nutritional physiological functions that qualify them to be classified under the functional food label. In this trends article we briefly describe the state-of-the-art of peptidomics methods for the identification and discovery of bioactive peptides, also considering recent progress in their analysis and highlighting the difficulty in the analysis of short amino acid sequences and endogenous peptides.

In vitro bioaccessibility of peptides and amino acids from yogurt made with starch, pectin, or β-glucan

The bioaccessibility of peptides and amino acids (AA) during in vitro gastrointestinal digestion of proteins from acid dairy gel (or yogurt) containing different polysaccharides (PS) was investigated. The nature of added PS was shown to modulate the kinetics of proteins gastric digestion. Yogurts with β-glucan and with pectin showed faster proteolysis, lower release of large peptides, and a higher proportion of free AA than those with starch or without PS. Segregation between β-glucan and dairy proteins was hypothesized to explain faster proteolysis by concentration of enzymes and proteins in a separated phase considered as “micro-reactors”. Kinetics of protein digestion during the buccal phase was not affected by the presence of PS in yogurts. At the beginning of duodenal phase yogurts with starch and with pectin showed a higher degree of hydrolysis; at the end of this phase proteins were fully digested (no native protein left and bioaccessible AA was increased).

In vitro study on digestion of peptides in Emmental cheese: Analytical evaluation and influence on angiotensin I converting enzyme inhibitory peptides

A simple in vitro protocol simulating gastrointestinal digestion of proteins and peptides to investigate the effect of digestive enzymes on the biological activity of peptides present in dairy products was developed. This protocol consisted in a 30 min incubation with pepsin followed by a 4 h incubation with trypsin or pancreatin. It was applied to an Emmental cheese water-soluble extract (WSE) and to a casein solution (as a control). Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) allowed to monitor the digestion of proteins. Reversed-phase high-performance liquid chromatography (RP-HPLC) allowed to monitor the conversion of proteins and peptides into peptides and amino acids: it is proposed to use the mean retention time corresponding to the overall retention time distribution of molecules to assess the effect of digestive enzymes. The biological activity focused in this study was the angiotensin I converting enzyme (ACE) inhibitory activity. Digestion of Emmental WSE induced an increase of the ACE inhibition as compared to undigested WSE while a 10 kDa ultrafiltered WSE lost a part of its ACE inhibitory activity after digestion process. These results strongly suggest that digestive enzymes diminished the ACE inhibition by the peptides present in Emmental cheese WSE, while the digestion of peptides of high molecular weight would generate new ACE inhibitory peptides.