How processing may affect milk protein digestion and overall physiological outcomes: A systematic review

Figures & data

Figure 1. Schematic overview of the reactions that can occur to milk proteins upon heating and how the state of the protein may have physiological consequences through differences in digestion.

Figure 2. Stages of the Maillard reaction between milk proteins and reducing sugars and commonly used markers to monitor each stage.

Figure 3. Schematic overview of different type of dairy processes and the ensuing dairy protein modifications occurring during these processes. Product flow indicated with solid arrows, protein modifications indicated with dotted boxes and dotted arrows. PTM, post-translation modifications.

Table 1. Search terms.

Product	Modification	Digestion	Physiological
Milk*	Glycat*	Digest*	Gastr*
Dairy	Maillard*	Absor*	Intestin*
Infant formula	Heat*	Proteoly*	Availab*
Whey	Furosine		Metabol*
Casein*	Brown*		In vitro
Lact*	Oxidat*		Grow*
	Therm*		Allerg*
	Aggregat*
	Denat*

Figure 4. Database search results according the PRISMA statement (Moher et al. 2009).

Table 2. Literature overview of studies investigating the impact of glycation on dairy protein digestibility.

Reference	Method	Protein source	Carbohydrate source	Glycation method	Study arms	Maillard products	Effect glycation on digestibility
Animal studies
(Alamir et al. 2013)	Nitrogen balance in rats	Sodium caseinate	Powdered biscuit ingredients	Biscuit extrusion	Non-extruded Extruded	CML formation	No significant effect on apparent digestibility
(Gilani and Sepehr 2003)	Nitrogen balance in rats	SMP	Lactose in SMP	Heating 121 °C for 1h	Unheated Heated	Not measured	Apparent protein digestibility was reduced in old and young rats
(Lacroix et al. 2006)	Nitrogen balance in rats	15N labeled milk	Lactose in milk	Spray-dry inlet 250 °C, outlet 87 °C	Non-heated Heated	Early Maillard	Nitrogen availability was lower for spray-dried
(Larsen et al. 2010)	Nitrogen balance in kittens and rats	Lactic casein	Dextrose	Heating at 121 °C for 2 h	Non-heated Heated	Early and advanced Maillard	Bioavailable lysine was reduced
(Moughan, Gall, and Rutherfurd 1996)	Nitrogen balance in pigs	Sodium caseinate	Glucose	Heating at 121 °C for 1 min and at 70 °C for 1 day	Unheated Heated	Early and advanced Maillard	Lower apparent ileal digestibility for lysine and AAs
(Moughan and Rutherfurd 1996)	Nitrogen balance in rats	Lactic casein	Lactose	Heating at 121 °C for 3.5 min	Unheated Heated	Early and advanced Maillard	Lower true ileal digestibility for lysine and AAs
(Rérat et al. 2002)	Nitrogen balance in pigs	SMP	Lactose in SMP	Roller-drying	Freeze-dried Roller-dried	Early Maillard	Decreased absorption of lysine and TAAs
(Rutherfurd and Moughan 2008)	Nitrogen balance in rats	SMP Hydrolyzed-lactose SMP	Lactose in SMP Hydrolyzed lactose in SMP	Storage at 30, 35 and 40 °C up to 18 months	Different storage times	Early and advanced Maillard	Lower true ileal digestibility for lysine
(Rutherfurd and Moughan 1997)	Nitrogen balance in rats	SMP	Lactose in SMP	Heating at 121 °C for 1, 3, 5 and 10 min	Unheated Heated	Early and advanced Maillard	Lower true ileal digestibility for lysine and most AAs
(Sarriá, López-Fandiño, and Vaquero 2000)	Nitrogen balance in rats	Infant formula	Lactose in IF	IF production	Powder UHT In-bottle sterilized	Early and advanced Maillard	Apparent digestibility was lower
(Sarwar, Peace, Botting, and Brulé, 1989)	Nitrogen balance in rats	SMP	Lactose in SMP	‘Overheated’	Unheated Heated	Not characterized	Apparent crude and true protein digestibility were lower and true lysine digestibility was lower
In vitro studies
(Cattaneo et al. 2017)	Infant in vitro digestion	Infant formula model systems	Lactose (L) Maltodextrin (M)	In batch sterilization, 110 °C 38 min	Commercial Noncommercial No L + M L + M	Furosine and pyrraline formation	Proteolysis was increased and decreased
(Corzo-Martínez et al. 2010)	Adult in vitro digestion	β-lactoglobulin	Galactose Tagatose Dextran 10 kDa Dextran 20 kDa	Heating at 40/50/60 °C with or without pyridoxamine	Not heated Heated	Early and advanced Maillard, cross-linking	Lower hydrolysis of intact β-lactoglobulin with higher glycation.
(Culver and Swaisgood 1989)	48h 2-step GI in vitro digestion	Sodium caseinate	Glucose	Storage at 30 or 60 °C for 0-30 days	Heated at 30 or 60 °C	Not measured	Protein digestibility was decreased
(Desrosiers and Savoie 1991)	Adult in vitro digestion	WPC	Lactose	Heating at 75, 100 and 121 °C for 50, 500 and 5000 s	Unheated Heated	Early and advanced Maillard	AA digestibility was decreased
(Desrosiers et al. 1989)	Adult in vitro digestion	WPC	Lactose	Heating at 75, 100 and 121 °C for 50, 500 and 5000 s	Unheated Heated	Early and advanced Maillard	Lysine digestibility was decreased
(Hellwig and Henle 2013)	72h 3-step GI in vitro digestion	β-casein	3-Deoxyglucosone	Heating at 70 °C for 10, 30, 60 and 180 min	Unheated Heated	Pyrraline formation	Protein digestibility was decreased
(Hiller and Lorenzen 2010)	Pancreatin in vitro digestion	Sodium caseinate WPI SMP	Glucose Lactose Pectin Dextran	Heating at 70 °C for 0-240 h at 65% RH	Unheated Heated	Short-term and long-term Maillard	Protein digestibility was decreased for sodium caseinate and increased for WPI
(Joubran, Moscovici, and Lesmes 2015)	Infant in vitro digestion	α-lactalbumin	Fructose FOS	Heating at 60 °C for 12 and 24 h (FOS) or 12 and 36 h (Fru) at 79% RH	Unheated Heated	Higher MWs and color development	Lower hydrolysis of intact α-lactalbumin with increased glycation
(Joubran et al. 2017)	Infant and in vitro digestion	α-lactalbumin	Glucose Galactose GOS	Heating at 60 °C for 12 and 24 h (GOS) or 12 and 36 h (Glu and Gal) at 79% RH	Unheated Heated	Higher MWs and color development	Glu, Gal and GOS-24h increased proteolysis. GOS-12h decreased proteolysis.
(Pinto et al. 2014)	Adult in vitro digestion	β-casein β-lactoglobulin A	Glucose	Heating solution at 90 °C up to 24 h	Unheated Heated	Advanced Maillard	Lower hydrolysis of intact β-casein and β-lactoglobulin
(Luz Sanz et al. 2007)	Adult in vitro digestion	β-lactoglobulin	GOS	Heating at 40 °C for 16 days at Aw 0.44	Unheated Heated	Early and advanced Maillard	Lower hydrolysis of intact β-lactoglobulin
(Zhao, Le, et al. 2017)	Adult in vitro digestion	β-casein β-lactoglobulin	Methylglyoxal Glyoxal Butanedione	Heated at 95 °C for 1 h	Unheated Heated	Advanced Maillard	Decrease in degree of hydrolysis
(Zhao, Li, et al. 2017)	Adult in vitro digestion	β-casein β-lactoglobulin	Methylglyoxal	Heated at 98 °C for 2h	Unheated Heated	Advanced Maillard	Decrease in hydrolysis of intact proteins and release of free AAs

CML, carboxymethyllysine; AA, amino acids; TAA, total amino acids; WPI, Whey protein isolate; SMP, Skimmed milk powder; IF, Infant formula; WPC, Whey protein concentrate; RH, relative humidity.

Table 3. Literature overview of studies investigating the impact of denaturation and aggregation on dairy protein digestibility.

Reference	Method	Protein source	Study arms with denaturation/aggregation method	Outcome measure	Effect on digestibility and digestion kinetics
Human study
(Lacroix et al. 2008)	In vivo, randomized intervention study using 15N labled milk	^15N labeled milk	Microfiltered milk Pasteurized milk (72 °C, 20 sec) UHT milk (140 °C, 5 sec)	Serum AA concentration Postprandial retention	No effect on overall serum AA concentrations; more sustained hyperaminoacidemia in the microfiltered group than UHT; more rapid kinetics for UHT; lower protein retention for UHT
Animal studies
(Barbé et al. 2013, 2014)	In vivo, cross-over digestion in 18-month-old adult mini pigs	Ultra-low heat SMP	Raw liquid milk derived from ultra-low heat skim milk powder Heated liquid milk (10 mins, 90 °C)	Protein hydrolysis (SDS-PAGE), Peptides (nano-RPLC MS/MS), cleavage score	Heat treatment increased plasma IAA bioavailability; made β-lactoglobulin more susceptible for hydrolysis; increased stomach retention time
(Efigenia, Povoa, and Moraes-Santos 1997)	In vivo digestion in Weanler Holtzman male rats	Whole milk	Raw milk Pasteurized milk (72 °C for 15 sec) Boiled milk (30 sec boiling) UHT milk (135-150 °C for few sec).	Apparent protein digestibility, growth	No differences in apparent protein digestibility. UHT milk impaired growth of weaning rats, which correlated with food intake.
(Kitabatake and Kinekawa 1998)	Static in vitro GI digestion and in vivo digestion in Wistar rats	β-lactoglobulin	Heated (80 °C, 1 h) and unheated β-lactoglobulin	Protein hydrolysis (SDS-PAGE), Size exclusion chromatography	Heating enabled pepsin hydrolysis of β-lactoglobulin in vitro and in vivo. Similar extent of pancreatic hydrolysis of native and heated β-lactoglobulin, but heated β-lactoglobulin more rapidly in vitro. Complete intestinal hydrolysis of heated and un-heated β-lactoglobulin
(Lacroix et al. 2006)	Nitrogen balance in rats	^15N labeled milk	Microfiltered milk HTST milk, 72 °C, 20 s HHST milk, 96 °C, 5 s UHT milk, 140 °C, 5 s	Digestibility, biological value and net postprandial protein utilization	Digestibility and biological value were similar between all milk products, and no correlation between temperature and nitrogen availability.
(Moughan et al. 1989)	Nitrogen balance in young pigs and in vitro flocculation test	SMP	Heated 74 °C, 121 °C 95 sec Heated 70 °C, 85 °C 105 sec, 102 °C 1 s Heated 85 °C, 118 °C 1 s Heated 77 °C, 102 °C 1 s	Mean apparent fecal and ileal digestibility, biological value and growth; flocculation	Higher levels of heat treatment led to a longer time to flocculation in vitro. Curd was firmer for the two least denatured samples. No effect of diet on apparent fecal and ileal digestibility, dietary nitrogen utilization and growth.
(Mpassi et al. 2001)	In vivo digestion in growing pigs	^15N labeled milk and yoghurt	Milk Yogurt Heat-treated yoghurt (80 °C for 10 min)	^15N aminonitrogen portal absorption	No differences in absorption rate (∼80%) between the milk products. The kinetics differed, absorption of N for milk and heat-treated yoghurt mainly occurred during the first 2 hours, while for yoghurt it was more evenly spread over 4 hours.
Static in vitro studies
(Carbonaro et al.,1997)	In vitro static enzymatic digestion with porcine pancreatic trypsin, bovine pancreatic chymotrypsin, porcine intestinal peptidase, followed by bacterial protease	Whole milk Whey protein extracts	Raw milk Pasteurized milk (15 sec at 72, 75, 78, 80 °C) UHT treated milk (3 and 5 sec at 145 °C), Sterilized milk (3 and 5 sec at 145 °C followed by autoclaving for 12 min at 118 °C or 10 min at 116 °C)	In vitro protein digestibility, whey protein solubility, whey amino acid composition	Digestibility increased from raw to pasteurized to UHT or sterilized whole milk. Digestibility of whey protein extracts decreased with increasing heat treatment.
(Dupont, Boutrou, et al. 2010)	Static in vitro infant GI digestion model	Ultra-low heat SMP	Heating at 80 °C, 20 s Heating at 85 °C, 180 s Heating at 105 °C, 60 s	SDS-PAGE, Western Blotting and LC MS-MS	β-lactoglobulin was still present after digestion in all samples. High processed samples show high resistance of intact caseins to digestion.
(Dupont, Mandalari, et al. 2010)	Static in vitro infant GI digestion model	Whole milk	Raw milk Pasteurized milk (30 s / 82 °C) Sterilized milk (10 min / 120 °C)	SDS-PAGE, Western Blotting and LC MS-MS	Pasteurization and sterilization increased gastric hydrlysis of β-lactoglobulin. Intact β-lactoglobulin was present after intestinal digestion for raw milk and pasteurized, not for sterilized. Sterilized milk showed higher resistance of casein peptides.
(Guo et al. 1995)	Static in vitro digestion with pepsin or trypsin	β-lactoglobulin	β-lactoglobulin heating at 70 to 100 °C for 5 or 10 minutes at pH 6.8 or pH 3.0	Protein hydrolysis (SDS-PAGE)	Native β-lactolgobulin resistant to peptic digestion, but heating at >80 °C enhanced proteolysis with increasing temperature.
(Lamothe et al. 2017)	Static in vitro GI digestion	Whole milk heated to 50 °C and skimmed, adding back 2% of fat	Pasteurized milk (65 °C, 30 min) Milk double homogenized and heated at 65 °C for 30 min Milk double homogenized and heated at 95 °C for 5 minutes.	Matrix degradation, protein hydrolysis	Heating at 95 °C increased hydrolysis in first 30 minutes of gastric digestion compared to 65 °C. Proteolysis was similar in intestinal phase, so after whole digestion, no difference in hydrolysis depending on heating.
(Lindberg et al. 1998)	In vitro static digestion with duodenal juice from adults	WPCs	WPC freeze-dried: 0% denaturation WPC spray-dried: 26% denaturation WPC heated 80 °C 15 sec, freeze-dried: 55% denaturation WPC heated 80 °C 30 min, freeze-dried: 97% denaturation	Digestion via polyacramide gradient gel electrophoresis, electroimmuno assay, nonprotein nitrogen	Digestibility of whey proteins decreased with higher degree of protein denaturation.
(Lorieau et al. 2018)	In vitro static GI digestion	Gels made by stirring and heating an emulsion of native whey protein and cream	Liquid native whey Hard gel (70 °C for 36.5 min at pH 6.4), Processed gel (75 °C for 19 min at pH 5.9), Whipped gel (75 °C for 80 min at pH 5.4)	Protein hydrolysis (SDS-PAGE), release of amino groups (OPA), amino acid concentration	Whey proteins were resistant to pepsin hydrolysis. Protein hydrolysis and amino acid release was higher in whey gels compared to the liquid native whey.
(Loveday et al. 2014)	Static in vitro gastric digestion	β-lactoglobulin	Heated β-lactoglobulin at 78 °C and 90 °C for 0, 5, 10, 20, 30, 40, 50, 60, 90 and 120 min	Peptide formation after hydrolysis (SDS-PAGE and RP-HPLC)	Native β-lactoglobulin shows initial slow digestion and rapid digestion after ∼4 hours. Heated β-lactoglobulin gives highly digestible non-native monomers, highly resistant dimers and β-lactoglobulin monomers bonded to peptides that are moderately digested. Distribution of those is influenced by heating time.
(Peram et al. 2013)	Static in vitro gastric digestion	β-lactoglobulin	β-lactoglobulin heated at 90 °C for 0-120 min	Protein and peptide characterization (SDS-PAGE and size exclusion chromatography	Heating increased initial hydrolysis of β-lactoglobulin with a correlation between hydrolysis and heating duration.
(Rahaman, Vasiljevic, and Ramchandran 2017)	Static in vitro GI digestion	β-lactoglobulin	β-lactoglobulin samples prepared with different pH (3, 5, 7), temperature (room temperature, 120 °C) and shear (0 s^−1, 1000 s^−1)	Degree of hydrolysis, peptide formation (SDS-PAGE), antigenicity assay	Unheated β-lactoglobulin was resistant to peptic digestion, but was susceptible to pancreatic digestion. Heating increased gastric and pancreatic digestion and resulted in lower antigenicity
(Rinaldi et al. 2014)	Static in vitro GI digestion	Commercial dairy products	Commercial pasteurized milk Commercial sterilized milk	Protein content and solubility, peptide analysis (SDS-PAGE), free amino acids.	No significant difference in soluble protein and free amino acid content between products after gastric and duodenal digestion. Faster digestion of caseins and whey in gastric phase in sterilized milk compared to pasteurized milk. β-lactoglobulin and A-lac degraded faster in sterilized in duodenal phase.
(Singh and Creamer 1993)	Static in vitro digestion with pepsin, trypsin or chymotrypsin	Low-heat SMP	Whey protein/k-casein complexes after heating at 90 °C for 5 min	SDS-PAGE	Unheated β-lactoglobulin is resistant to proteolysis by pepsin. Degree of hydrolysis by trypsin or chymotrypsin was much lower for unheated β-lactoglobulin than in the heated complexes. Hydrolysis of κ-casein was higher for the complexes compared to unheated as well.
(Singh et al. 2014)	Static in vitro GI digestion	WPI	WPI WPI gels heated at 90 °C for 10 min at pH 6.8 and 4.6	Protein and peptide analysis (SDS-PAGE and RP-HPLC)	In the gastric phase, whey proteins in gels are faster hydrolyzed than in native solution. Intestinal hydrolysis of WPI in solution was slowest.
(Stender et al. 2018)	Static in vitro GI digestion	Serum protein concentrate	Heat denatured SPC (1 hour, 85 °C)	TCA soluble peptides	Heat treatment lowered gastric digestion rate. No difference in hydrolysis in the intestinal phase.
(Tunick et al. 2016)	Static in vitro GI digestion	Bovine milk	Raw unprocessed milk Raw skimmed milk Raw whole milk HTST pasteurized milk UHT processed skimmed milk	Protein analysis (SDS-PAGE) and particle size distribution	In the raw samples, caseins and α-lactalbumin were broken down in gastric phase, β-lactoglobulin was resistant. This was similar for pasteurized milk. UHT showed hydrolysis of β-lactoglobulin. During intestinal digestion, bands for β-lactoglobulin faded within 15 min for raw and UHT and 30 min for pasteurized.
(Wada and Lönnerdal 2014)	Static in vitro GI digestion and in vivo digestion in rat pups	Milk and liquid enteral formula	Pasteurized milk (73 °C for 15 sec) UHT milk (140 °C for 2 sec) Steam infused milk (135 °C for 2 sec) Steam injected liquid enteral formula milk (151 °C for 4 sec) In can sterilized liquid formula (121 °C for 20 min)	Protein and peptide analysis (SDS-PAGE, Kjeldahl)	Protein hydrolysis of casein, α-lactalbumin and β-lactoglobulin was rapid for in can sterilized and UHT milk, due to denaturation. No differences in protein digestibility.
(Semi)-dynamic in vitro studies
(Mulet-Cabero et al. 2019)	Semi dynamic in vitro gastric adult digestion	Bovine milk	Raw milk Raw homogenized milk Pasteurized milk Pasteurized homogenized milk UHT milk UHT homogenized milk	Gastric behavior, nutrients emptied and protein digestion (SDS-PAGE)	Raw milk forms a firmer coagulum, whereas heated samples and UHT in particular give a more open coagulum with more pores. Pasteurized and raw milk showed β-lactoglobulin present during gastric digestion, while β-lactoglobulin could only be observed in the two first gastric emptying points for UHT. UHT had a higher protein release in the early stages of digestion.
(Sánchez-Rivera et al. 2015)	Dynamic in vitro gastric digestion	SMP	Non-heated skimmed milk prepared from SMP Heated (90 °C, 10 min) skimmed milk	Protein and peptide analysis (SDS-PAGE, LC MS/MS), immunoreactivity	Heating increased resistance to pepsin hydrolysis for casein, while β-lactoglobulin became more susceptible to pepsin hydrolysis. Time of release of peptides was different between heated and unheated.
(Wang and Zhao 2017)	In vitro dynamic gastric digestion	WPI	Whey protein isolate Heated whey protein isolate (90 °C for 20 min)	Curd weight, pH, protein hydrolysis (SDS-PAGE)	No aggregation in native WPI over whole digestion, while aggregation occurred in heated WPI in the stomach. For unheated WPI, β-lactoglobulin remained intact during whole digestion and decreased gradually with time. β-lactoglobulin for heated WPI was much less and disappeared. Peptides were visible in emptied digests from heated WPI, but not for unheated WPI, where native β-lactoglobulin remained intact. α-lactalbumin did not show any difference between unheated and heated WPI.
(Ye et al. 2017)	In vitro dynamic gastric digestion	Whole milk	Unprocessed raw whole milk Homogenized milk Heat-treated homogenized whole milk (90 °C for 20 min)	Curd weight, pH, protein hydrolysis	Homogenization and heat treatment leads to more fragmented and crumbled curds leading to greater rates of protein hydrolysis. Emptied digests from heated milk contained only small amounts of intact caseins and whey, while unheated samples showed emptying of intact β-lactoglobulin and α-lactalbumin.

AA, amino acids; IAA, indispensable amino acids; UHT, ultra-high temperature; WPI, whey protein isolate; SMP, Skimmed milk powder; GI, gastrointestinal; HTST, high temperature, short time pasteurized; HHST, higher temperature, shorter time pasteurized; TCA, trichloroacetic acid; WPC, whey protein concentrate; SPC, serum protein concentrate.

Moher, D., A. Liberati, J. Tetzlaff, D. G. Altman, and P. Grp. 2009. Preferred reporting items for systematic reviews and meta-analyses: The PRISMA statement (reprinted from Annals of Internal Medicine). Physical Therapy 89 (9):873–80. doi: 10.1371/journal.pmed.1000097.

 PubMed Web of Science ®Google Scholar

Alamir, I., C. Niquet-Leridon, P. Jacolot, C. Rodriguez, M. Orosco, P. M. Anton, and F. J. Tessier. 2013. Digestibility of extruded proteins and metabolic transit of N ε-carboxymethyllysine in rats. Amino Acids 44 (6):1441–9. doi: 10.1007/s00726-012-1427-3.

 PubMed Web of Science ®Google Scholar

Gilani, G. S., and E. Sepehr. 2003. Protein digestibility and quality in products containing antinutritional factors are adversely affected by old age in rats. The Journal of Nutrition 133 (1):220–5. doi: 10.1093/jn/133.1.220.

 PubMed Web of Science ®Google Scholar

Lacroix, M., J. Léonil, C. Bos, G. Henry, G. Airinei, J. Fauquant, D. Tomé, and C. Gaudichon. 2006. Heat markers and quality indexes of industrially heat-treated [15N] milk protein measured in rats. Journal of Agricultural and Food Chemistry 54 (4):1508–17. doi: 10.1021/jf051304d.

 PubMed Web of Science ®Google Scholar

Larsen, J. A., A. J. Fascetti, C. C. Calvert, and Q. R. Rogers. 2010. Bioavailability of lysine for kittens in overheated casein is underestimated by the rat growth assay method. Journal of Animal Physiology and Animal Nutrition 94 (5):e102. doi: 10.1111/j.1439-0396.2010.00988.x.

 PubMed Web of Science ®Google Scholar

Moughan, P. J., M. P. J. Gall, and S. M. Rutherfurd. 1996. Absorption of lysine and deoxyketosyllysine in an early-Maillard browned casein by the growing pig. Journal of Agricultural and Food Chemistry 44 (6):1520–5. doi: 10.1021/jf950428v.

 Web of Science ®Google Scholar

Moughan, P. J., and S. M. Rutherfurd. 1996. A new method for determining digestible reactive lysine in foods. Journal of Agricultural and Food Chemistry 44 (8):2202–9. doi: 10.1021/jf950032j.

 Web of Science ®Google Scholar

Rérat, A., R. Calmes, P. Vaissade, and P. A. Finot. 2002. Nutritional and metabolic consequences of the early Maillard reaction of heat treated milk in the pig. Significance for man. European Journal of Nutrition 41 (1):1–11. doi: 10.1007/s003940200000.

 PubMed Web of Science ®Google Scholar

Rutherfurd, S. M., and P. J. Moughan. 2008. Effect of elevated temperature storage on the digestible reactive lysine content of unhydrolyzed- and hydrolyzed-lactose milk-based products. Journal of Dairy Science 91 (2):477–82. doi: 10.3168/jds.2007-0612.

 PubMed Web of Science ®Google Scholar

Rutherfurd, S. M., and P. J. Moughan. 1997. Application of a new method for determining digestible reactive lysine to variably heated protein sources. Journal of Agricultural and Food Chemistry 45 (5):1582–6. doi: 10.1021/jf960788y.

 Web of Science ®Google Scholar

Sarriá, B., R. López-Fandiño, and M. P. Vaquero. 2000. Protein nutritive utilization in rats fed powder and liquid infant formulas.. Food Science and Technology International 9 (1):9–16.

 Google Scholar

Sarwar, G., R. W. Peace, H. G. Botting, and D. Brulé. 1989. Digestibility of protein and amino acids in selected foods as determined by a rat balance method. Plant Foods for Human Nutrition 39 (1):23–32. doi: 10.1007/BF01092398.

 PubMed Web of Science ®Google Scholar

Cattaneo, S., M. Stuknytė, F. Masotti, and I. De Noni. 2017. Protein breakdown and release of β-casomorphins during in vitro gastro-intestinal digestion of sterilised model systems of liquid infant formula. Food Chemistry 217:476–82. doi: 10.1016/j.foodchem.2016.08.128.

 PubMed Web of Science ®Google Scholar

Corzo-Martínez, M., A. C. Soria, J. Belloque, M. Villamiel, and F. J. Moreno. 2010. Effect of glycation on the gastrointestinal digestibility and immunoreactivity of bovine β-lactoglobulin. International Dairy Journal 20 (11):742–52. doi: 10.1016/j.idairyj.2010.04.002.

 Web of Science ®Google Scholar

Culver, C. A., and H. E. Swaisgood. 1989. Changes in the digestibility of dried casein and glucose mixtures occurring during storage at different temperatures and water activities. Journal of Dairy Science 72 (11):2916–20. doi: 10.3168/jds.S0022-0302(89)79442-X.

 Web of Science ®Google Scholar

Desrosiers, T., and L. Savoie. 1991. Extent of damage to amino acid availability of whey protein hearted with sugar. Journal of Dairy Research 58 (4):431–41.

 PubMed Web of Science ®Google Scholar

Desrosiers, T., L. Savoie, G. Bergeron, and G. Parent. 1989. Estimation of lysine damage in heated whey proteins by furosine determinations in conjunction with the digestion cell technique. Journal of Agricultural and Food Chemistry 37 (5):1385–91. doi: 10.1021/jf00089a039.

 Web of Science ®Google Scholar

Hellwig, M., and T. Henle. 2013. Release of pyrraline in absorbable peptides during simulated digestion of casein glycated by 3-deoxyglucosone. European Food Research and Technology 237 (1):47–55. doi: 10.1007/s00217-013-2027-5.

 Web of Science ®Google Scholar

Hiller, B., and P. C. Lorenzen. 2010. Functional properties of milk proteins as affected by Maillard reaction induced oligomerisation. Food Research International 43 (4):1155–66. doi: 10.1016/j.foodres.2010.02.006.

 Web of Science ®Google Scholar

Joubran, Y., A. Moscovici, and U. Lesmes. 2015. Antioxidant activity of bovine alpha lactalbumin Maillard products and evaluation of their in vitro gastro-duodenal digestive proteolysis. Food & Function 6 (4):1229–40. doi: 10.1039/C4FO01165A.

 PubMed Web of Science ®Google Scholar

Joubran, Y., A. Moscovici, R. Portmann, and U. Lesmes. 2017. Implications of the Maillard reaction on bovine alpha-lactalbumin and its proteolysis during in vitro infant digestion. Food & Function 8 (6):2295–308. doi: 10.1039/C7FO00588A.

 PubMed Web of Science ®Google Scholar

Pinto, M. S., J. Léonil, G. Henry, C. Cauty, A. Ô. F. Carvalho, and S. Bouhallab. 2014. Heating and glycation of β-lactoglobulin and β-casein: Aggregation and in vitro digestion. Food Research International 55:70–6. doi: 10.1016/j.foodres.2013.10.030.

 Web of Science ®Google Scholar

Luz Sanz, M., M. Corzo-Martínez, R. a Rastall, A. Olano, and F. J. Moreno. 2007. Characterization and in vitro digestibility of bovine beta-lactoglobulin glycated with galactooligosaccharides. Journal of Agricultural and Food Chemistry 55 (19):7916–25. doi: 10.1021/jf071111l.

 PubMed Web of Science ®Google Scholar

Zhao, D., T. T. Le, L. B. Larsen, L. Li, D. Qin, G. Su, and B. Li. 2017. Effect of glycation derived from α-dicarbonyl compounds on the in vitro digestibility of β-casein and β-lactoglobulin: A model study with glyoxal, methylglyoxal and butanedione. Food Research International 102:313–22. doi: 10.1016/j.foodres.2017.10.002.

 PubMed Web of Science ®Google Scholar

Zhao, D., L. Li, T. T. Le, L. B. Larsen, G. Su, Y. Liang, and B. Li. 2017. Digestibility of glyoxal-glycated β-casein and β-lactoglobulin and distribution of peptide-bound advanced glycation end products in gastrointestinal digests. Journal of Agricultural and Food Chemistry 65 (28):5778–88. doi: 10.1021/acs.jafc.7b01951.

 PubMed Web of Science ®Google Scholar

Lacroix, M., C. Bon, C. Bos, J. Léonil, R. Benamouzig, C. Luengo, J. Fauquant, D. Tomé, and C. Gaudichon. 2008. Ultra high temperature treatment, but not pasteurization, affects the postprandial kinetics of milk proteins in humans. The Journal of Nutrition 138 (12):2342–7. doi: 10.3945/jn.108.096990.

 PubMed Web of Science ®Google Scholar

Barbé, F., O. Ménard, Y. Le Gouar, C. Buffière, M.-H. Famelart, B. Laroche, S. Le Feunteun, D. Dupont, and D. Rémond. 2013. The heat treatment and the gelation are strong determinants of the kinetics of milk proteins digestion and of the peripheral availability of amino acids. Food Chemistry 136 (3–4):1203–12. doi: 10.1016/j.foodchem.2012.09.022.

 PubMed Web of Science ®Google Scholar

Barbé, F., S. Le Feunteun, D. Rémond, O. Ménard, J. Jardin, G. Henry, B. Laroche, and D. Dupont. 2014. Tracking the in vivo release of bioactive peptides in the gut during digestion: Mass spectrometry peptidomic characterization of effluents collected in the gut of dairy matrix fed mini-pigs. Food Research International 63:147–56. doi: 10.1016/j.foodres.2014.02.015.

 Web of Science ®Google Scholar

Efigenia, M., B. Povoa, and T. Moraes-Santos. 1997. Effect of heat treatment on the nutritional quality of milk proteins. International Dairy Journal 7 (8/9):609–12. doi: 10.1016/S0958-6946(97)00049-6.

 Web of Science ®Google Scholar

Kitabatake, N., and Y. I. Kinekawa. 1998. Digestibility of bovine milk whey protein and β-lactoglobulin in vitro and in vivo. Journal of Agricultural and Food Chemistry 46 (12):4917–23. doi: 10.1021/jf9710903.

 Web of Science ®Google Scholar

Moughan, P. J., M. N. Wilson, C. H. M. Smits, and W. C. Smith. 1989. An evaluation of skim milk powders subjected to different heating conditions during processing as dietary protein sources for the young pig. Animal Feed Science and Technology 22 (3):203–15. doi: 10.1016/0377-8401(89)90062-X.

 Web of Science ®Google Scholar

Mpassi, D., G. Rychen, M. Mertes, and F. Laurent. 2001. Portal absorption of 45Ca from labelled milk, yoghurt or heat treated yoghurt in the growing pig. International Dairy Journal 11 (10):809–15. doi: 10.1016/S0958-6946(01)00107-8.

 Web of Science ®Google Scholar

Carbonaro, M., M. Cappelloni, S. Sabbadini, and E. Carnovale. 1997. Disulfide reactivity and in vitro protein digestibility of different Thermal-Treated milk samples and whey proteins. Journal of Agricultural and Food Chemistry 45 (1):95–100. doi: 10.1021/jf950828i.

 Web of Science ®Google Scholar

Dupont, D., R. Boutrou, O. Menard, J. Jardin, G. Tanguy, P. Schuck, B. B. Haab, and J. Leonil. 2010. Heat treatment of milk during powder manufacture increases casein resistance to simulated infant digestion. Food Digestion 1 (1–2):28–39. doi: 10.1007/s13228-010-0003-0.

 Google Scholar

Dupont, D., G. Mandalari, D. Mollé, J. Jardin, O. Rolet-Répécaud, G. Duboz, J. Léonil, C. E. N. Mills, and A. R. Mackie. 2010. Food processing increases casein resistance to simulated infant digestion. Molecular Nutrition & Food Research 54 (11):1677–89. doi: 10.1002/mnfr.200900582.

 PubMed Web of Science ®Google Scholar

Guo, M. R., P. F. Fox, A. Flynn, and P. S. Kindstedt. 1995. Susceptibility of β-lactoglobulin and sodium caseinate to proteolysis by pepsin and trypsin. Journal of Dairy Science 78 (11):2336–44. doi: 10.3168/jds.S0022-0302(95)76860-6.

 PubMed Web of Science ®Google Scholar

Lamothe, S., N. Rémillard, J. Tremblay, and M. Britten. 2017. Influence of dairy matrices on nutrient release in a simulated gastrointestinal environment. Food Research International 92:138–46. doi: 10.1016/j.foodres.2016.12.026.

 PubMed Web of Science ®Google Scholar

Lindberg, T., S. Engberg, L. B. Sjöberg, and B. Lönnerdal. 1998. In vitro digestion of proteins in human milk fortifiers and in preterm formula. Journal of Pediatric Gastroenterology & Nutrition 27 (1):30–6. doi: 10.1097/00005176-199807000-00006.

 PubMed Web of Science ®Google Scholar

Lorieau, L., A. Halabi, A. Ligneul, E. Hazart, D. Dupont, and J. Floury. 2018. Impact of the dairy product structure and protein nature on the proteolysis and amino acid bioaccessiblity during in vitro digestion. Food Hydrocolloids 82:399–411. doi: 10.1016/j.foodhyd.2018.04.019.

 Web of Science ®Google Scholar

Loveday, S. M., M. R. Peram, H. Singh, A. Ye, and G. B. Jameson. 2014. Digestive diversity and kinetic intrigue among heated and unheated β-lactoglobulin species. Food Funct. 5 (11):2783–91. doi: 10.1039/C4FO00362D.

 PubMed Web of Science ®Google Scholar

Peram, M. R., S. M. Loveday, A. Ye, and H. Singh. 2013. In vitro gastric digestion of heat-induced aggregates of β-lactoglobulin. Journal of Dairy Science 96 (1):63–74. doi: 10.3168/jds.2012-5896.

 PubMed Web of Science ®Google Scholar

Rahaman, T., T. Vasiljevic, and L. Ramchandran. 2017. Digestibility and antigenicity of β-lactoglobulin as affected by heat, pH and applied shear. Food Chemistry 217:517–23. doi: 10.1016/j.foodchem.2016.08.129.

 PubMed Web of Science ®Google Scholar

Rinaldi, L., S. F. Gauthier, M. Britten, and S. L. Turgeon. 2014. In vitro gastrointestinal digestion of liquid and semi-liquid dairy matrixes. LWT - Food Science and Technology 57 (1):99–105. doi: 10.1016/j.lwt.2014.01.026.

 Web of Science ®Google Scholar

Singh, H., and L. K. Creamer. 1993. In vitro digestibility of whey protein/k-casein complexes isolated from heated concentrated milk. Journal of Food Science 58 (2):299–302. doi: 10.1111/j.1365-2621.1993.tb04260.x.

 Web of Science ®Google Scholar

Singh, T. K., S. K. Øiseth, L. Lundin, and L. Day. 2014. Influence of heat and shear induced protein aggregation on the in vitro digestion rate of whey proteins. Food & Function 5 (11):2686–98. doi: 10.1039/C4FO00454J.

 PubMed Web of Science ®Google Scholar

Stender, E. G. P., G. Koutina, K. Almdal, T. Hassenkam, A. Mackie, R. Ipsen, and B. Svensson. 2018. Isoenergic modification of whey protein structure by denaturation and crosslinking using transglutaminase. Food & Function 9 (2):797–805. doi: 10.1039/C7FO01451A.

 PubMed Web of Science ®Google Scholar

Tunick, M. H., D. X. Ren, D. L. Van Hekken, L. Bonnaillie, M. Paul, R. Kwoczak, and P. M. Tomasula. 2016. Effect of heat and homogenization on in vitro digestion of milk. Journal of Dairy Science 99 (6):4124–39. doi: 10.3168/jds.2015-10474.

 PubMed Web of Science ®Google Scholar

Wada, Y., and B. Lönnerdal. 2014. Effects of different industrial heating processes of milk on Site-Specific protein modifications and their relationship to in vitro and in vivo digestibility. Journal of Agricultural and Food Chemistry 62 (18):4175–85. doi: 10.1021/jf501617s.

 PubMed Web of Science ®Google Scholar

Mulet-Cabero, A.-I., A. R. Mackie, P. J. Wilde, M. A. Fenelon, and A. Brodkorb. 2019. Structural mechanism and kinetics of in vitro gastric digestion are affected by process-induced changes in bovine milk. Food Hydrocolloids 86:172–83. doi: 10.1016/j.foodhyd.2018.03.035.

 Web of Science ®Google Scholar

Sánchez-Rivera, L., O. Ménard, I. Recio, and D. Dupont. 2015. Peptide mapping during dynamic gastric digestion of heated and unheated skimmed milk powder. Food Research International 77:132–9. doi: 10.1016/j.foodres.2015.08.001.

 Web of Science ®Google Scholar

Wang, X. P., and X. H. Zhao. 2017. Prior lactose glycation of caseinate via the Maillard reaction affects in vitro activities of the pepsin-trypsin digest toward intestinal epithelial cells. Journal of Dairy Science 100 (7):5125–38. doi: 10.3168/jds.2016-12491.

 PubMed Web of Science ®Google Scholar

Ye, A., J. Cui, D. Dalgleish, and H. Singh. 2017. Effect of homogenization and heat treatment on the behavior of protein and fat globules during gastric digestion of milk. Journal of Dairy Science 100 (1):36–47. doi: 10.3168/jds.2016-11764.

 PubMed Web of Science ®Google Scholar