Dairy proteins and soy proteins in infant foods nitrogen-to-protein conversion factors

Maubois, Jean‐Louis; Lorient, D.

doi:10.1007/s13594-015-0271-0

Cited by 44 publications

(30 citation statements)

References 35 publications

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“…In the past two decades, however, many studies have been published reporting NPCF for many different foods. Some researchers have adhered to the definitions and calculations proposed by Mossé () while others, particularly those investigators evaluating dairy protein, have based their calculations on novel approaches such as protein sequencing of individual proteins (Maubois and Lorient, ; Rouch et al, ) because separation methods to quantitate the relative proportions of milk proteins in dairy foods have been developed (Strange et al, ). Two conclusions can be drawn from reviewing the published literature: (1) there are inconsistencies in the analytical methods used to derive NPCF for foods (e.g., number and conditions for hydrolysis for amino acid analyses, method of total N determination) and (2) using the approach delineated by Mossé (), calculated NPCF for nearly all foods are not 6.25 but are less than 6.25 (Marriotti et al, ; Salo‐Väänänen and Koivistoinen, ; Sosulski and Imafidon, ).…”

Section: Application Of Npcf After Mossémentioning

confidence: 99%

“…It should be noted that the inclusion of prosthetic group weights in the NPCF calculation is only conducted by dairy protein analysts. Maubois and Lorient () also consider low molecular weight peptides and free amino acids as NPN, despite many investigators indicating that for nutritional considerations all amino acids should be considered as protein equivalents (Greenfield and Southgate, ; Marriotti et al, ; Tkachuk, ).…”

Section: Npcf For Soybean Proteinmentioning

confidence: 99%

“…Maubois and Lorient () reported NPCF of 5.69–5.79 for soy protein based on their proposal that the amino acid sequence of proteins or primary structure of proteins be used for the calculations. They claimed to use direct sequence data of β‐conglycinin and glycinin from Utsumi et al () to calculate the NPCF for soy protein; however, sequences would be listed for the different protein subunits whose relative proportions vary in the soybean, so it is not clear how the NPCF were calculated.…”

Section: Npcf For Soybean Proteinmentioning

confidence: 99%

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Calculation of Nitrogen‐to‐Protein Conversion Factors: A Review with a Focus on Soy Protein

Krul¹

2019

J Americ Oil Chem Soc

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Protein content in foods and feeds is measured indirectly by nitrogen determination, requiring a nitrogen‐to‐protein conversion factor (NPCF). Historically, 6.25 was applied to all proteins based on two assumptions: (1) all proteins had a nitrogen content of 16% (100/16 = 6.25) and (2) all nitrogen was derived from protein. Amino acid analyses revealed that a conversion factor of 6.25 overestimated the protein content of most foods due to variations in amino acid profiles and nonprotein nitrogen. The lack of standardization of methods to determine food‐specific NPCF has resulted in continued use of 6.25 and inconsistent development of new factors. This review summarizes efforts made to derive NPCF for various foods. Soy protein has been the subject of considerable debate since publication of the “Jones factors” in 1931, which based the soy conversion factor of 5.71 on the nitrogen content of glycinin. Nonetheless, 6.25 is still used by the soy industry, analytic associations, and government regulatory bodies. Given the impact to the valuation of soy protein products and food relabeling costs, changes to soy alone appear discriminatory in the absence of standardized methods for developing NPCF for all proteins. Proposed solutions include (1) developing a consensus method to determine NPCF applicable to all foods, (2) applying standardized NPCF to measure protein in all foods and assessing the economic, nutritional, and regulatory consequences equitably, and (3) developing standardized direct methods to measure protein, such as amino acid analyses, in foods intended as single sources in vulnerable populations where more accurate measurement and reducing any risk of adulteration with nonprotein nitrogen are essential.

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Section: Application Of Npcf After Mossémentioning

confidence: 99%

Section: Npcf For Soybean Proteinmentioning

confidence: 99%

Section: Npcf For Soybean Proteinmentioning

confidence: 99%

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Calculation of Nitrogen‐to‐Protein Conversion Factors: A Review with a Focus on Soy Protein

Krul¹

2019

J Americ Oil Chem Soc

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“…Soy protein isolate is the product more used in the food industry for different purposes such as infant formula, nutraceutics products, functional foods, milks, and beverages [23][24][25]. There is extensive research looking for new sources of vegetal proteins (amaranto, quinoa, pea, and lupinus).…”

Section: Discussionmentioning

confidence: 99%

Gastrointestinal Digestion of Kahai Protein Concentrate (Caryodendron Orinocense Karst)

Greffa

Barrionuevo²,

Vilcacundo³

et al. 2018

Asian J Pharm Clin Res

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Objective: The aim of this study was to obtain kahai protein concentrate from Caryodendron orinocense karst cultivated in the region Amazonia of Ecuador and characterizes its gastric and duodenal hydrolysates using the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) electrophoresis method and the reversed-phase ultra-high-performance liquid chromatography (RP-UHPLC) method. Methods:Kahai seeds (C. orinocense karst) were utilized to obtain kahai protein concentrate at pH 5.0 using the isoelectric precipitation method and then subject to gastric hydrolysis with pepsin enzyme (2000 U/mg of protein) at pH 1.2, pH 2.0, and pH 3.2 at 37°C for 2 h with agitation in simulated gastric fluids and then to duodenal hydrolysis with pancreatin (mix enzymes) at pH 7.0 at 37°C for 3 h with agitation in simulated intestinal fluid. Gastric and duodenal hydrolysates from kahai were characterized using the SDS-PAGE electrophoresis method and the RP-UHPLC chromatography method. Results:Proteins obtained from kahai (C. orinocense karst) were hydrolyzed with pepsin, only one protein with molecular weight of 100 kDa presented resistance to hydrolysis with pepsin at all pHs assayed. All proteins from kahai protein concentrate were totally hydrolyzed with pancreatin in in vitro conditions. Conclusion:This study suggests that kahai protein concentrates have a high grade of digestibility in vitro when using the gastroduodenal model of digestion. Kahai protein can be a good source of alternative vegetal proteins to be consumed by animals and humans.

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“…However, in recent years some have suggested that for soy protein a NCF of 5.71 should be used rather than 6.25 [24]. The 5.71 factor that is being proposed originally came from the work of D.B.…”

Section: Nutrient Contentmentioning

confidence: 99%

Soy and Health Update: Evaluation of the Clinical and Epidemiologic Literature

2016

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Soyfoods have long been recognized as sources of high-quality protein and healthful fat, but over the past 25 years these foods have been rigorously investigated for their role in chronic disease prevention and treatment. There is evidence, for example, that they reduce risk of coronary heart disease and breast and prostate cancer. In addition, soy alleviates hot flashes and may favorably affect renal function, alleviate depressive symptoms and improve skin health. Much of the focus on soyfoods is because they are uniquely-rich sources of isoflavones. Isoflavones are classified as both phytoestrogens and selective estrogen receptor modulators. Despite the many proposed benefits, the presence of isoflavones has led to concerns that soy may exert untoward effects in some individuals. However, these concerns are based primarily on animal studies, whereas the human research supports the safety and benefits of soyfoods. In support of safety is the recent conclusion of the European Food Safety Authority that isoflavones do not adversely affect the breast, thyroid or uterus of postmenopausal women. This review covers each of the major research areas involving soy focusing primarily on the clinical and epidemiologic research. Background information on Asian soy intake, isoflavones, and nutrient content is also provided.

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Dairy proteins and soy proteins in infant foods nitrogen-to-protein conversion factors

Cited by 44 publications

References 35 publications

Calculation of Nitrogen‐to‐Protein Conversion Factors: A Review with a Focus on Soy Protein

Calculation of Nitrogen‐to‐Protein Conversion Factors: A Review with a Focus on Soy Protein

Gastrointestinal Digestion of Kahai Protein Concentrate (Caryodendron Orinocense Karst)

Soy and Health Update: Evaluation of the Clinical and Epidemiologic Literature

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