Relative Tryptic Digestion Rates of Food Proteins (original) (raw)
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Journal of AOAC INTERNATIONAL, 2005
The kinetics of peptide release during in vitro digestion of 4 protein sources (casein, cod protein, soy protein, and gluten) were investigated. Samples were sequentially hydrolyzed with pepsin (30 min) and pancreatin (2, 4, or 6 h) in a dialysis cell with continuous removal of digestion products. Nondialyzed digests were fractionated by ion-exchange chromatography and ultrafiltration. Animal proteins were digested at a greater rate than plant proteins. Target amino acids of specific enzymes appeared more rapidly in the dialyzed fractions when compared to other amino acids. Throughout the hydrolysis, nondialyzed digests contained a higher proportion of peptide mixtures with basic-neutral properties. Except for gluten, peptide fractions with molecular weights that exceeded 10 kDa (basic-neutral, BN > 10) were rapidly hydrolyzed during the first 2 h of pancreatin digestion. The kinetics of release and the composition of peptide fractions were different when the protein sources were...
Digestibility of proteins from different sources
The Annals of the University Dunarea de Jos of Galati Fascicle VI – Food Technology, 2020
In vitro protein digestibility can be useful for estimating protein nutritional quality. Eight protein sources were chosen to study in vitro protein digestibility, namely: sodium caseinate, whey, mushrooms, pea, soy, oat, hemp and sea buckthorn. Trypsin was used to achieve the enzymatic hydrolysis and the pH-drop technique was employed to determine in vitro protein digestibility. Substrate hydrolysis was rapidly initiated after enzyme addition in the case of pea protein, sodium caseinate, soy and whey proteins, whereas a slower pH decrease was registered in the case of mushroom proteins. The in vitro protein digestibility decreased in the following order: pea (87.2%) > soy (85.9%) > whey (85.6%) > caseinate (85%) > hemp (78.5%) > oat (77.5%) > sea buckthorn (76.2%) > mushrooms (68.2%). The sea buckthorn and mushrooms samples with the lowest protein contents (15.6% and 18.3%, respectively) had the lowest protein digestibility. However, no correlation between protein content and protein digestibility was found.
Protein digestion of different protein sources using the INFOGEST static digestion model
2020
In vitro digestion systems are valuable tools for understanding and monitoring the complex behavior of food degradation during digestion, thus proving to be good candidates for replacing in vivo assays. The aim of the present work was to study protein hydrolysis in a selection of different protein sources using the harmonized INFOGEST static protocol: three isolated proteins (collagen, zein, and whey protein) and five foods (sorghum flour, wheat bran cereals, peanuts, black beans, and pigeon peas). The proteins of all the substrates were analyzed by SDS-PAGE and HPLC-MS/MS. Individual amino acid composition was analyzed by high-performance liquid chromatography (HPLC). EAA/NEAA (essential amino acids/ nonessential amino acids) ratios in the substrates from low to high were as follows: wheat bran cereals, peanuts, collagen, zein, whey protein, sorghum, pigeon peas, and black beans. The results revealed sorghum, whey protein, and zein as good sources of BCAA. In all substrates, no intact protein from the substrates was visually detected by SDS-PAGE after the intestinal phase of in vitro digestion with the INFOGEST protocol. However, digestion-resistant peptides were detected in all substrates after the intestinal digestion phase. Protein hydrolysis was high in whey protein isolate and pigeon pea and low for wheat bran cereals and bovine collagen.
Food protein functionality: A comprehensive approach
Food Hydrocolloids, 2011
Food protein functionality has classically been viewed from the perspective of how single molecules or protein ingredients function in solutions and form simple colloidal structures. Based on this approach, tests on protein solutions are used to produce values for solubility, thermal stability, gelation, emulsifying, foaming, fat binding and water binding to name a few. While this approach is beneficial in understanding the properties of specific proteins and ingredients, it is somewhat restricted in predicting performance in real foods where the complexities of ingredients and processing operations have a significant affect on the colloidal structures and therefore overall properties of the final food product. In addition, focusing on proteins as just biopolymers used to create food structures ignores the biological functions of proteins in the diet. These can be beneficial, as in providing amino acids for protein synthesis or bioactive peptides, or these can be detrimental, as in causing a food allergic response. This review will focus on integrating the colloidal/polymer and biological aspects of protein functionality. This will be done using foams and gels to illustrate colloidal/polymer aspects and bioactive peptides and allergenicity to demonstrate biological function.
Scientific Background of Dairy Protein Digestibility: A Review
Journal of Food Science and Technology Nepal, 2014
Recent advances have shown that differences in compositional, structural and physical properties of caseins and whey proteins affect their digestion and absorption behavior, hormonal response, satiety effect and other physiological effects. For example, the ingestion of whey protein cause fast, high and transient increase of amino acids ‘fast protein’, whereas casein induce slower, lower and prolonged increase of ‘slow protein’ in the gut. Knowledge of, and control over, the rate and nature of digestive breakdown of dairy proteins provides a potential basis for product/process innovation through identifying ingredients and formulations that provide desired nutrient delivery profiles. With this background, the aim of our current review paper is to understand the digestion behavior of various protein-rich milk powders and their potential use in formulation of dairy foods for controlled release of amino acids and energy. Currently available in vitro protein digestibility methods to mea...
Journal of Food Biochemistry, 1992
7he effects of various food components on the in vitro digestibility of proteins, measured by the immobilized digestive enzyme assay (IDEA) system, were investigated. The digestibility of unprocessed and processed sodium caseinate and soybean protein was examined. Varying concentrations of sucrose (0, 5, 10 and 20%) or starch (0, 0.5, I and 2 %) had no sign$cant effects on digestibility of protein. Similarly, the presence of emulsij?ed (I X lecithin) vegetable oil (0, 0.5, 1 and 2%) did not aflect digestibility. fierefore, these common ingredients of foods did not affect the extent of hydrolysis of the protein samples under the conditions of the IDEA method, suggesting that this assay is suitable for use with complex foods.
LC/MS and LC/MS/MS determination of protein tryptic digests
Journal of the American Society for Mass Spectrometry, 1990
T~yptic~igests were analyzed by means of online microbore liquid chromatography commed WIth m~ss~pec~rome~ry (LC/~S) for some c~mmo~proteins. Following conventional enzym~tIc .dIgestIon WIth trypsm, the freeze-dried r.esIdues were dissolved in high-p~rformanceliquid chromatography (HPLC) eluent and subjected to gradient reversed-phase microbore HPLC separation with mass spectrometric detection. The latter was done in thẽ ull-scan sin~le or tandem (MS/MS) mas~spectrometry mode. The formation of gas-phase lOn~from dissolved analytes was accomplished at atmospheric pressure by pneumatically assisted electrospray (ion spray) ionization. This produced field-assisted ion evaporation of dissolved ions, which could then be mass-analyzed for molecular mass or structure. In the full-scan LC/MS mode, the masses for the peptide fragments in the tryptic digests can be determi~ed a~eithe~their singly or multiply charged ions. When the molecular weights of the peptides he outside the mass range of the mass spectrometer, the multiply charged feature of these experimental conditions still provides reliable molecular weight determinations. I~addition, collision-activated dissociation (CAD) on selected peptide precursor ions provides online LC/MS/MS sequence information for the tryptic fragments. Results are shown for the tryptic digests of horse heart cytochrome c, bovine ,a-lactoglobulin A, and bovine ,a-lactoglobulin B.
An evaluation of open and closed systems for in vitro protein digestion of fish meal
Aquaculture …, 1997
The availability of a rapid, cost-effective, accurate and reliable method of assessing fish meal protein digestibility would greatly enhance and standardize quality-control procedures in both the fish meal and fish feed industries. However, while several in vitro digestibility tests have been developed, few have been adopted by industry due to their time-consuming nature, problems surrounding reliability and/or inconsistencies in predictive ability. The present investigation was undertaken to evaluate the utility and predictive qualities of two in vitro digestion assays of distinct design. Methods examined included a novel open system, wherein on-line removal of digestion products was attainable, and a closed system, which permitted analysis of products following completion of the digestion process. Results provided by the two systems were compared using four differentially processed fish meals. The open system supplied information based upon the detected quantity of products below 10 kDa. The closed system provided measurement of free amino groups. Both methods were in agreement with respect to assessing the presence of hydrolysed product. Both systems furnished complementary data with respect to the characterization of fish meal protein quality. The closed and open systems provided insight upon digestibility and digestion kinetic profiles respectively.
A Collaborative Study to Develop a Standardized Food Protein Solubility Procedure
Journal of Food Science, 1985
A colaborative study was conducted to develop a rapid, simple and reliable procedure for determining the solubility of food protein products, e.g., spray-dried whey protein concentrate, sodium caseinate, egg white protein and soy protein isolate. The procedure was developed by modifying the nitrogen solubility index (NSI) procedure. Protein content and soluble protein were determined by micro-Kjeldahl or biuret procedures with standard deviations of ? 0.83-4.12 for all proteins except caseinate which had a value of Y? 13.95. Although the biuret and micro-Kjeldahl procedures generally provided comparable accuracy and precision for protein content and solubility of certain proteins, the biuret procedure exhibited considerable error and variability for other proteins.
Quantitative measurement of protein digestion in simulated gastric fluid
Regulatory Toxicology and Pharmacology, 2005
The digestibility of novel proteins in simulated gastric fluid is considered to be an indicator of reduced risk of allergenic potential in food, and estimates of digestibility for transgenic proteins expressed in crops are required for making a human-health risk assessment by regulatory authorities. The estimation of first-order rate constants for digestion under conditions of low substrate concentration was explored for two protein substrates (azocoll and DQ-ovalbumin). Data conformed to first-order kinetics, and half-lives were relatively insensitive to significant variations in both substrate and pepsin concentration when high purity pepsin preparations were used. Estimation of digestion efficiency using densitometric measurements of relative protein concentration based on SDS-PAGE corroborated digestion estimates based on measurements of dye or fluorescence release from the labeled substrates. The suitability of first-order rate constants for estimating the efficiency of the pepsin digestion of novel proteins is discussed. Results further support a kinetic approach as appropriate for comparing the digestibility of proteins in simulated gastric fluid.