Whey-based cheese provides more postprandial plasma leucine than casein-based cheese: A pig study

Experimental Protocols Used to Mimic Gastrointestinal Protein Digestion: A Systematic Review

Bioactive peptides derived from native proteins modulate physiological processes in the metabolic pathways. Given that multiple protocols in the literature mimic the digestion of dietary components, gathering studies that use such models directed at protein digestion processes is critical. This systematic review aimed to gather evidence that adopted adequate experimental models to simulate human protein digestion. The databases searched were PubMed, Web of Science, ScienceDirect, Embase, Virtual Health Library, and Scopus. A total of 1985 articles were found, resulting in 20 eligible in vitro studies. The Office of Health Assessment and Translation was used to evaluate methodological quality. Seven studies used plant-based protein sources, twelve used animal protein sources, and one used both. The duration of the oral phase varied, although 60% of the studies employed a protein digestion period of 120 min. Amylase, pepsin, and pancreatin enzymes were utilized in 40% of the studies, with pH levels of 7, 3, and 7, respectively, during the oral, gastric, and intestinal phases. The INFOGEST harmonized static model was adopted by 65% of the studies; INFOGEST is the most effective model for simulating gastrointestinal protein processes in humans and can be used to answer several research questions because it describes experimental conditions close to the human physiological situation.

Utilizing the influence of protein enrichment of meal components as a strategy to possibly prevent undernutrition in the elderly: an in vitro approach

Nutritional strategies are required to limit the prevalence of denutrition in the elderly. With this in mind, fortified meals can provide more protein, but their digestibility must be ensured. Using a dynamic in vitro digester, DIDGI®, programmed with the digestion conditions of the elderly, we evaluated the supplementation of each component of a meal and assessed protein digestibility, amino acid profile, micro-nutrients and vitamins bioaccessibility for a full course meal. Higher protein digestibility was evidenced for the fortified meal, with higher release of essential amino acids. Moreover the large increase of leucine released was comparable to the range advocated for the elderly to favour protein anabolism. This in vitro study underlines the interest of using dish formulations to meet the nutritional needs of seniors, which is why this work will be completed by a clinical study in nursing home.

In vitro digestion of two protein-rich dairy products in the ageing gastrointestinal tract

It is still unclear if changes in protein digestibility and absorption kinetics in old age may affect the anabolic effect of high-protein foods. The objective of this study was to investigate the digestion of two high-protein (10% w/w) dairy products in vitro: a fermented dairy product formulated with a ratio of whey proteins to caseins of 80 to 20% (WBD) and a Skyr containing mainly caseins. The new static in vitro digestion model adapted to the general older adult population (≥65 years) proposed by the INFOGEST international consortium was implemented to investigate the digestion of these products and compared with the standard version of the protocol. Kinetics of proteolysis was compared between both models for each product, in the gastric and intestinal phases of digestion. Protein hydrolysis was studied by the OPA method, SDS-PAGE, and LC-MS/MS, and amino acids were quantified by HPLC. Protein hydrolysis by pepsin was slower with the older adult model than with the young adult model, and consequently, in spite of a longer gastric phase duration, the degree of proteolysis (DH) at the end of the gastric phase was lower. Two different scenarios were observed depending on the type of dairy product studied: -10 and -40% DH for Skyr and WBD, respectively. In the intestinal phase, lower concentrations of free leucine were observed in older adult conditions (approx. -10%), but no significant differences in proteolysis were observed overall between the models. Therefore, the digestion conditions used influenced significantly the rate and extent of proteolysis in the gastric phase but not in the intestinal phase.

In vitro digestion models for the design of safe and nutritious foods

Responsible development of future foods requires in depth understanding of food digestion in the human body based on robust research models, ranging from in vitro models to randomized controlled human trials. This chapter overviews fundamental aspects of food digestion, namely bioaccessibility and bioavailability, and models mirroring gastric, intestinal, and colonic conditions. Second, the chapter demonstrates the potential of in vitro digestion models to help screen adverse effects of food additives, such as Titanium dioxide or carrageenan, or underpin the determinants of macro- and micronutrient digestion in different strata of the population, for example digestion of emulsions. Such efforts support rationalized design of functional foods, such as infant formulae, cheese, cereals and biscuits which are validated in vivo or in randomized controlled trials.

Sustainable Approaches in Whey Cheese Production: A Review

Whey cheeses have been produced from the very early steps of cheesemaking practices as a sustainable way to utilize whey, which is the main by-product of cheesemaking. Traditional whey cheeses, manufactured with similar processes, are Ricotta, Ricotta salata or Ricottone, and Ricotta fresca in Italy; Anthotyros, Myzithra, Manouri, Xynomyzithra, and Urda in Greece; Urda in Serbia and Romania as well as in other countries such as Israel; Lor in Turkey; Anari in Cyprus; Skuta in Croatia and Serbia; Gjetost and Brunost in Norway; Mesost and Messmör in Sweden; Mysuostur in Iceland; Myseost in Denmark; Requeijão in Portugal; and Requesón in Spain and Mexico. The production of whey cheese is based on the denaturation of whey proteins by heating to 88–92 °C. The specific processing conditions and aspects of the microbiology of whey cheeses are discussed. The special characteristics of whey cheeses, which are high pH and high moisture content, make them susceptible to microbial growth. Due to the limited shelf life of these products, extended research has been carried out to extend the shelf life of whey cheese. The sustainable preservation approaches, such as modified atmosphere packaging, addition of herbs and/or plant extracts, and bio-preservation methods are reviewed. Moreover, novel whey cheeses focused on functional properties have developed during the last 10 years.

Advances in research on calf rennet substitutes and their effects on cheese quality

Milk coagulation is an important step in cheese production, and milk-clotting enzymes (MCEs) play a major role in this process. Calf rennet is the most widely used MCE in the cheese industry. The use of calf rennet substitutes is becoming necessary due to the limited availability of calf rennet and the increase in cheese consumption. The objective of this review is to summarize the latest findings on calf rennet substitutes (animal MCEs, plant-derived MCEs, recombinant MCEs and microbial MCEs) and their application in cheese production. Special emphasis has been placed on aspects of the effects of these substitutes on hydrolysis, functional peptides, cheese variety and cheese yield. The advantages and disadvantages of different calf rennet substitutes are discussed, in which microbial MCEs have the advantages of less expensive production, greater biochemical diversity, easier genetic modification, etc. In particular, some of these MCEs have suitable characteristics for cheese production and are considered to be the most potential calf rennet substitutes. Moreover, challenges and future perspectives are presented to provide inspiration for the development of excellent calf rennet substitutes.

Digestive characteristics and peptide release from wheat embryo proteins in vitro

Due to the scarcity of the data on digestion and metabolism of wheat embryo proteins WEP, a simulated gastrointestinal digestion (SGID) scheme in vitro was utilized to explain the protein hydrolysis and biological activity of WEP during the digestion process. WEP had a certain degree of resistance to gastric digestion, especially the protein with a molecular weight of 50 kDa. In all the samples, no visually intact protein band emerged in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) during the intestinal phase, which was consistent with a gradually increasing content of released free amino acids. Moreover, the resistant digestion peptides (the amino acid sequences were ISQFXX and GTVX) were identified at the end of the gastrointestinal digestion (GID) product by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Although the complete protein in the sample was degraded, the antioxidant activity was not negatively affected, rather it showed an increasing trend and maintained a higher level of activity. The amount of the β-sheet gradually increased as that of the α-helix declined, the random coil decreased, whereas no obvious change was noticed in β-turn content. The results provide a better understanding for optimal selection of peptide candidates for designing protein products in the food processing industry as well as for WEP digestion and metabolism in the human body.

Using recombinant camel chymosin to make white soft cheese from camel milk

Bovine derived chymosin in rennet cannot coagulate camel milk (CAM). The study aimed at producing cheese curd from CAM using a recombinant camel chymosin. Pasteurized CAM was prepared for curdling using a recombinant camel chymosin (50 IMCU/ kg). CAM (pH 6.65) contained 2.83% Fat, 3.34% proteins and 9.11% non-fat solids. Physicochemical properties of soft cheese from cultured CAM were 51.89%, 15.62%, 20.21% and 2.47% for moisture, protein, fat and ash, respectively. Cultured CAM afforded higher cheese yield (8.75%) than non-cultured CAM (3.34%). CAM cheese whey had 48.94% and 76.80% of the fat and proteins, respectively, of their corresponding concentrations in CAM. The study is the first report on soft cheeses from CAM (cultured and non-cultured) using a recombinant camel chymosin, with reference to whey constituents. CAM cheese and whey could be added-value products.