Effects of pH Variation and NaCl on In Vitro Digestibility of Cow's Milk Proteins in Commercially Available Infant Formulas.

Sakai, Kentaro; Yoshino, Kenji; Satter, Mohammed A.; Ota, Fusao; Nii, Yoshitaka; Fukuta, Kazuhiro; Ueda, Nobuo; Shimizu, Yūji; Yamamoto, Shigeru

doi:10.3177/jnsv.46.325

Cited by 29 publications

(28 citation statements)

References 10 publications

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“…This is also indicated by the intensity of the bands at a molecular weight of approximately 23 and 24 kDa for α-and β-casein, respectively, that show a slight decrease in intensity towards the end of one hour (Fig 4.3, S60). Similar observations were reported by Sakai et al (2000). In the intestinal phase, the enzymes trypsin and chymotrypsin completely digested α-casein and β-casein.…”

Section: Discussionsupporting

confidence: 89%

“…This indicates that the β-lactoglobulin was completely hydrolysed by trypsin and chymotrypsin, as observed in an earlier study by Kitabatake & Kinekawa, (1998). The negligible digestion of β-lactoglobulin during one hour in stomach at pH 1.5-7.0 has also been reported in earlier studies (Li, Zhu, Zhou, Peng, and Guo, 2013;Inglingstad et al, 2010;Chatterton et al, 2004;Sakai et al, 2000, Kitabatake & Kinekawa, 1998Astwood et al, 1996).…”

Section: Discussionsupporting

confidence: 79%

“…Some past researchers have reported limited digestion of α-lactalbumin in cow's milk, human milk, and infant formula under simulated gastric digestion using human gastric juices or commercial porcine pepsin (Chatterton, Rasmussen, Heegaard, Sørensen, & Petersen, 2004;Sakai et al, 2000;Jakobsson, Lindberg, and Benediktsson, 1982). Jakobsson et al (1982) observed that only 1 mg of α-lactalbumin as opposed to 30 mg of casein was digested under the same condition at pH 4.5-5.0…”

Section: Whey Proteinmentioning

confidence: 99%

“…Sakai et al (2000) studied the in vitro gastric digestibility of α-lactalbumin of commercial infant formula at pH 1.5-4.0.…”

Section: Whey Proteinmentioning

confidence: 99%

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Digestibility and structural changes of ingredients in infant formulae during the gastrointestinal digestion

Nguyen¹

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Although mothers' milk is the ideal food for babies, infant formula has become an alternative when breastfeeding is not possible or inadequate for babies. To design a proper formula for babies, it is essential to understand the digestibility of macronutrients and their bio-accessibility in the infant gastrointestinal tract. Because in vivo gastrointestinal studies on human infants are restricted by ethical constraint, cost issues, and intensive resource, in vitro models could be a better replacement.In vitro models offer advantages with low cost, easy sampling accessibility and no ethical issues. This thesis aims to assess the digestibility of each ingredient proteins, lipids, and carbohydrates in infant formulation then compare with mothers' milk. A static bench-top in vitro model for infant digestion was set up with infant gastric pH (4.0-4.5) and the activity of simulated digestive enzymes suitable for human infants with 60 minutes of gastric phase and 120 minutes of intestinal phase.Popular protein sources of caseins, whey, and soy proteins were employed in infant formulations.The in vitro digestion of these proteins in infant formulations was studied in the presence of enzyme proteases only (without lipolytic enzymes). Obtained results showed around 20% of caseins and no components of whey were hydrolysed after 60 minutes in the simulated stomach. In the simulated intestinal phase, 8% of α-lactalbumin was hydrolysed while caseins and β-lactoglobulin were completely digested immediately and 30 minutes respectively after addition of intestinal digestive proteases. Overall, soy proteins indicated lower level of hydrolysis than dairy proteins during in vitro infant digestion as observed by SDS-PAGE. The soy protein fractions glycinin and β-conglycinin were partially hydrolysed during the gastrointestinal phase. The observed pH drop confirms that caseins are easily digested in the intestinal phase compared to whey and soy protein. Gastric digestion resulted in a decrease of the particle size of protein aggregates, but no fat coalescence was observed during both gastric and intestinal digestion in the given conditions.The in vitro digestion of hydrolysed and non-hydrolysed dairy (casein and whey proteins) was studied under conditions without lipolytic enzymes. Results show hydrolysed proteins were completely digested in the small intestine while non-hydrolysed proteins (caseins, α-lactalbumin, β-lactoglobulin, conglycinin, glycinin) were only partially digested in the simulated gastrointestinal tract. Although observed pH-drop for non-hydrolysed protein formulations was lower, significantly higher levels of ninhydrin-reactive amino nitrogen in hydrolysed proteins suggested higher digestibility of hydrolysed proteins than their non-hydrolysed counterparts. Only formulations containing caseins showed a decrease in particle size of protein aggregates during gastric digestion. No fat globule coalescence was observed during both gastric and intestinal digestions in the given conditions. Lipid digestion of infa...

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Section: Discussionsupporting

confidence: 89%

Section: Discussionsupporting

confidence: 79%

Section: Whey Proteinmentioning

confidence: 99%

“…Sakai et al (2000) studied the in vitro gastric digestibility of α-lactalbumin of commercial infant formula at pH 1.5-4.0.…”

Section: Whey Proteinmentioning

confidence: 99%

See 2 more Smart Citations

Digestibility and structural changes of ingredients in infant formulae during the gastrointestinal digestion

Nguyen¹

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“…ACE is a dipeptidyl carboxypeptidase which catalyses both the production of the vasoconstrictor angiotensin-II and the inactivation of the vasodilator bradykinin, the inducing hypertensive effects. Measurement of peptic digestibility of cow's milk protein in commercially available infant foods under various pH conditions showed interesting results (Sakai et al, 2000). Aqueous solutions of infant formula were acidi!…”

Section: Literatures On In Vitro Protein Digestibility Studiesmentioning

confidence: 99%