Calcium (Ca), primarily consumed through diet, is essential for skeletal health and various other biological functions in humans. While the mechanisms of Ca absorption are well understood, little is known about the role of food structure properties in Ca release kinetics into the GIT, which may have important implications in Ca uptake. Therefore, the aim of this study was to investigate calcium release kinetics from whey protein matrices with varying structures during gastrointestinal digestion. Whey protein structures (liquid: storage modulus G' = 0.18 Pa at 1 Hz; soft gel: 1791 Pa; hard gel: 4103 Pa) with 8% (w/w) protein and an equal Ca concentration (25 mM CaCl2) were subjected to dynamic in vitro gastric digestion using the Human Gastric Simulator, followed by intestinal digestion of emptied chyme fractions using a static model. Results revealed that the release of both soluble and ionic Ca from whey protein gels was significantly delayed, compared with their liquid counterpart. Slower Ca release patterns from protein gels in the gastric phase led to the release of a higher soluble Ca content in the intestinal phase, especially at early stages of digestion. These findings demonstrated that the physical structure of whey protein gels modulates soluble Ca release rates into the gastrointestinal environment. Further research is required to understand the implications of calcium release modulation in absorption efficiency.
Across both in vitro and in vivo models, ultra-low molecular weight collagen (LMWCP), with more than 45% di- and tripeptides, exhibited faster early-phase absorption kinetics, thereby enhancing early-phase bioavailability.
Reyhan Nergiz-Unal, Stephan Dierckx, C. Roye et al.· PeerJ· 0 citations
Dietary protein regulates gastric emptying, which may further influence postprandial glycemic response and subsequent food intake. However, how different meat protein sources affect gastric emptying and the underlying mechanisms remain unclear. In this study, we compared the effects of meat proteins from chicken, duck, goose, pork, and mutton on gastric emptying rates, dextrin-induced glycemic response, and food intake in rats. Their digestive properties were further analyzed using a static in vitro digestion model to investigate the relationship between protein digestion characteristics and gastric emptying. In vivo results showed that duck and mutton proteins exhibited slower gastric emptying than other proteins, accompanied by attenuated postprandial glycemic response and reduced food intake. In vitro, these proteins exhibited lower gastric digestibility and peptide release, together with greater surface hydrophobicity, higher β-sheet content, and delayed protein degradation and particle size reduction during digestion. These findings suggest that the higher structural stability of meat proteins, as reflected in the retention of β-sheet content and higher surface hydrophobicity, may reduce susceptibility to enzymatic hydrolysis and slow chyme evolution, including particle size reduction and the formation of soluble digestion products, which may contribute to delayed gastric emptying. Our study sheds light on how protein structural properties influence gastric digestion and emptying, providing a basis for designing meat-based foods with specific digestive behaviors and metabolic responses.
Hongxia Liu, Feifan Zhang, Yang Zhai et al.· Food Research International· 0 citations
Age-related declines in gastrointestinal function increase the malnutrition risk and highlight the need for lipid formulations with digestive and metabolic characteristics suited to older populations. In this study, a structurally characterized medium- and long-chain triacylglycerol (MLCT) prepared by enzymatic transesterification was compared with a compositionally equivalent physical blend (PB) using a simulated in vitro gastrointestinal digestion model for the elderly and an in vivo indirect calorimetry in adult mice. MLCT exhibited a more gradual fatty acid release pattern and 33–44% lower lipolysis during the initial gastrointestinal stages than PB without affecting final hydrolysis, and it significantly improved polyunsaturated fatty acid bioaccessibility. In mice, MLCT administration was associated with comparatively gradual changes in whole-body energy expenditure and respiratory gas exchange among the lipid treatments. These findings indicate that the TAG structure influences digestive kinetics and acute whole-body metabolic responses, supporting the further evaluation of MLCT for nutritional applications involving age-related digestive decline.
Chenyu Jiang, Yi-Xiao Huang, Xinyi Cheng et al.· Journal of Agricultural and...· 0 citations
Background: Calcium formulations are important nutritional interventions for improving insufficient calcium intake and assisting in the prevention and treatment of osteoporosis. In vitro and in vivo performance may be influenced by dosage form, calcium source, and formulation composition. In this study, an integrated approach combining in vitro dissolution, pharmacokinetic, and pharmacodynamic evaluations was used to compare the comprehensive performance of nine calcium formulations and related functional components. Methods: The nine samples were coded as CS-1 to CS-9 according to a predefined order. Calcium release characteristics were determined under simulated gastrointestinal pH conditions using a flow-through cell system. Calcium concentrations in rat plasma, feces, and urine were measured by inductively coupled plasma optical emission spectrometry (ICP-OES) to evaluate calcium exposure, excretion, and retention. Meanwhile, the bone-protective effects of different calcium preparations were assessed in a retinoic acid-induced osteoporotic ICR mouse model, and the pharmacodynamic performance of calcium citrate and various bone-derived peptide preparations was investigated in a calcium-deficient female Sprague–Dawley (SD) rat model. Results: CS-1 exhibited rapid and nearly complete calcium release in simulated gastric fluid and showed a relatively favorable dissolution profile under sequential gastrointestinal pH conditions. Calcium balance analysis indicated that calcium retention in rats was relatively higher after administration of CS-1. Animal experiments showed that different calcium sources and bone-derived peptide preparations improved bone-related parameters to varying degrees, among which CS-1 produced relatively consistent improvements in bone microarchitecture and biomechanical properties. As a functional component of the CS-1 formulation, salmon bone-derived ingredients showed activity in the comparative pharmacodynamic evaluation, suggesting that they may contribute to the overall bone-protective effect. Conclusions: Different calcium formulations showed distinct profiles in dissolution behavior, calcium retention, and bone-protective effects. Among the tested samples, CS-1 demonstrated relatively favorable overall performance, which may be related to its liquid dosage form and salmon bone-derived functional components.
Conventional calcium supplements often show limited bioaccessibility and suboptimal gastrointestinal tolerance. Food-derived proteins, protein hydrolysates, and peptide–calcium chelates have been investigated as protein-based calcium chelates. This review organizes these systems along a structural continuum from proteins to hydrolysates and peptide–calcium chelates, in which enzymatic hydrolysis, fractionation, purification, and chelation reshape carrier composition, molecular weight distribution, and calcium coordination characteristics. Within this framework, this review examines the preparation strategies, molecular features, gastrointestinal stability, intestinal transport behavior, and bone-related functions of protein-based calcium chelates. Particular attention is given to the effects of chelate type, molecular weight distribution, peptide sequence, and coordination stability on calcium retention, solubility, and transport-related behavior during digestion, as well as their links with osteogenic responses, gut microbiota changes, and the gut–bone axis. Overall, this review provides a structured framework for evaluating food-derived protein-based calcium chelates and their potential application in food-based calcium delivery systems, while highlighting future needs in functional validation, product standardization, safety assessment, and clinically relevant evidence.
Tingting Li, Yaxiong Gao, Qiang Zhou et al.· Frontiers in Nutrition· 0 citations
This review assesses the critical role of the food matrix (FM) in regulating peptide bioavailability, addressing the new challenge of overcoming low oral absorption of diverse peptide classes and advocating for matrix-engineered delivery systems (such as microencapsulation and probiotic fermentation) to establish a holistic, matrix-aware approach to functional food design.
Chunhong Liu, Chao-Qing Wen, O. Olatunji et al.· The Journal of the Science o...· 0 citations
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