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Numerous calcium sources are available to enrich food, but their behavior during digestion is still unknown. This study focused on the influence of the gastro-intestinal pH, the food structure and the calcium source on the bioaccessibility of the nutrient. Four calcium sources were studied: calcium carbonate, calcium citrate malate, calcium phosphate and calcium bisglycinate. These were added to dairy matrices, containing cream and whey proteins, of different forms (liquid or gel). The kinetics of solubility and ionic calcium concentration during in vitro digestion were studied, as function of gastro-intestinal pH. All calcium sources were almost fully soluble in the gastric compartment, and then became insoluble in the intestinal phase. The level of calcium insolubilisation in the intestinal phase was not significantly influenced by the matrix structure (liquid or gel), but was more dependent on the calcium source, this effect leading to different final calcium bioaccessibility from 36% to 20%. [ABSTRACT FROM AUTHOR]

Infant formulas (IFs) can be defined as substitutes for human milk, which are mostly based on cow milk proteins. For sustainability reasons, alternative to animal proteins in food have to be considered. Plant proteins offer interesting nutritional and functional benefits for the development of innovative IFs. However, the behaviour of these proteins during processing and storage must ensure the physical stability and ability to reconstitution of IF powders, and that needs to be tested. This work aimed to study how a partial substitution of dairy proteins by plant proteins may influence the functional properties of 1st age IFs. Three IFs were developed at a semi-industrial scale using two different processing routes. The IFs composition was identical, except that 50% of the proteins were whey proteins in the "reference IF" (RIF), and pea or faba bean proteins in the "plant IFs" (PIF and FIF, respectively). After reconstitution, the three IFs result in similar stable emulsions with equivalent free fat release. In comparison to RIF, PIF and FIF were difficult to disperse, conducting to remaining insoluble particles. Thus, the protein source greatly influences IFs properties, and process parameters need to be adapted for each formulation to meet IFs quality criteria. • Plant protein dispersibility is the limiting factor all along IFs manufacturing. • Similar emulsion stability and free fat were found for plant and dairy IFs. • Homogenization partly improved dispersion of plant protein aggregates. • Protein source had a great impact on IF manufacturing and functionalities. [ABSTRACT FROM AUTHOR]

[Display omitted] • Yogurts and CM products were degraded faster compared to milks and SM products. • In vitro degree of lipolysis was higher for SM products compared to CM ones. • In vitro degree of proteolysis was higher for milks compared to yogurts. • ⍺-lactalbumin was degraded faster in SM products compared to CM products. • In vitro calcium bioaccessibility was greater in SM products. Sheep's milk (SM) is known to differ from cow's milk (CM) in nutritional composition and physicochemical properties, which may lead to different digestion behaviours. This work aimed to investigate the impact of the species (cow vs sheep) and the structure (milk vs yogurt) on the digestion of dairy products. Using an in vitro static gastrointestinal digestion model, CM, SM, cow's milk yogurt (CY) and sheep's milk yogurt (SY) were compared on particle size evolution, microscopic observations, degree of lipolysis, degree of proteolysis, specific protein degradation and calcium bioaccessibility. Species and structure affected particle size evolution during the gastric phase resulting in smaller particles for yogurts compared to milks as well as for CM products compared to SM products. Species impacted lipid composition and lipolysis, with SM products presenting higher short/medium-chain fatty acids content and higher intestinal degree of lipolysis. Proteolysis was influenced by structure, with milks showing higher intestinal degree of proteolysis compared to yogurts. Caseins were digested faster in CM, ⍺-lactalbumin was digested faster in SM despite its higher concentration, and during gastric digestion β-lactoglobulin was more degraded in CM products compared to SM products and more in yogurts compared to milks. Lastly, SM products released more bioaccessible calcium than CM products. In conclusion, species (cow vs sheep) impacted more the digestion compared to the structure (milk vs yogurt). In fact, SM was different from CM mainly due to a denser protein network that might slow down the accessibility of the enzyme to its substrate which induce a delay of gastric disaggregation and thus lead to slower the digestion of the nutrients. [ABSTRACT FROM AUTHOR]