Comparison of the Kjeldahl method and a combustion method for total nitrogen determination in animal feed

Marcó, Alejandro

doi:10.1016/s0039-9140(02)00136-4

Cited by 101 publications

(41 citation statements)

References 5 publications

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“…Protein was measured using the Kjeldahl method of nitrogen analysis. 18 Fat content was determined using the Soxhelt method for quantitative determination. Carbohydrate content was assessed by calculation.…”

Section: Macro-and Micronutrient Analysismentioning

confidence: 99%

Breast milk macro‐ and micronutrient composition in lactating mothers from suburban and urban Shanghai

Qian

Chen

et al. 2010

J Paediatrics Child Health

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Section: Macro-and Micronutrient Analysismentioning

confidence: 99%

Breast milk macro‐ and micronutrient composition in lactating mothers from suburban and urban Shanghai

Qian

Chen

et al. 2010

J Paediatrics Child Health

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“…The nitrogen content of the supernatant was measured using the Dumas combustion method (Marcó et al, 2002) on an NA 2100 nitrogen and protein analyzer (Thermo Scientific, Rodano, Italy). After calibration with urea or methionine, the protein concentration was calculated using the nitrogen-protein conversion factors of 6.25 for α-lactalbumin, 5.29 for lysozyme, and 6.02 for BSA.…”

Section: Protein Contentmentioning

confidence: 99%

Interactions between globular proteins and procyanidins of different degrees of polymerization

Prigent

Voragen

Koningsveld

et al. 2009

Journal of Dairy Science

104

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Interactions of proteins with phenolic compounds occur in food products containing vegetable sources, such as cocoa, cereals, or yogurts containing fruit. Such interactions can modify protein digestion and protein industrial properties. Noncovalent interactions between globular proteins (proteins important in industry) and procyanidins (phenolic compounds present in large quantity in fruits) were studied. The affinity constants between procyanidins of various average degrees of polymerization (DP) and lysozyme or alpha-lactalbumin were measured by isothermal titration calorimetry. The effects of these interactions on protein solubility and foam properties were examined using alpha-lactalbumin and BSA. Weak interactions were found with epicatechin and procyanidin dimers. Procyanidins of n = 5.5 and n = 7.4 showed medium (1.5 x 10(5) M(-1)) and high (8.69 x 10(9) M(-1)) affinities, respectively, for alpha-lactalbumin at pH 5.5, with n the average number of subunits per oligomer. A positive cooperativity of binding at low procyanidin:protein molar ratios was observed. The affinities of alpha-lactalbumin and lysozyme for procyanidins increased when the pH was close to the isoelectric pH. Solubility of lysozyme was strongly decreased by procyanidins of n = 5.5, whereas alpha-lactalbumin and BSA were less affected. Protein solubility in the presence of procyanidins was not affected by increased ionic strength but increased slightly with temperature. Procyanidins of n = 5.5 and n = 7.4 stabilized the average bubble diameter of foam formed with alpha-lactalbumin but had no effect on foam made from BSA. These results indicate that procyanidins of medium can lead to an undesirable decrease of protein solubility, but may play a positive role in foam stability.

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“…Chemical analyses: Chemical analysis was conducted with whole seed material. Nitrogen and sulphur analyses were performed according to the methods of Kjeldahl and Dumas, respectively (Marco et al. 2002, AOAC Official Method 990.03).…”

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confidence: 99%

Seed protein amino acid composition of important local grain legumes Lupinus angustifolius L., Lupinus luteus L., Pisum sativum L. and Vicia faba L.

Schumacher¹,

Paulsen²,

Gau

et al. 2011

Plant Breeding

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Grain legumes are regarded as highly valuable protein source for human and animal nutrition. Legume protein quality is mainly limited by the amino acids (AAs) tryptophan and sulphur AA. Organic farming in particular requires high seed protein quality for livestock feeding, as chemically produced AAs must not be feeded. Breeding attempts to increase contents of limiting AA are required. In the present survey, the AA content of 107 cultivars of important European grain legume species (Lupinus angustifolius, Lupinus luteus, Pisum sativum and Vicia faba) was analysed. AA contents were related to the requirements of growing pigs and human nutrition. Feed quality could be enhanced by choice of high quality varieties according to ideal protein concepts. For example for sulphur, AA feed quality for pigs could be increased by up to 22% (e.g. for L. angustifolius: ideal protein = 100, sample mean = 59.7, sample maximum = 72.7). Regarding livestock nutrition, ranges of limiting AA never reached the qualities reported for soybean seeds. However, an inclusion of high quality legume lines would reduce the need for other high quality components in feed compositions.

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Comparison of the Kjeldahl method and a combustion method for total nitrogen determination in animal feed

Cited by 101 publications

References 5 publications

Breast milk macro‐ and micronutrient composition in lactating mothers from suburban and urban Shanghai

Breast milk macro‐ and micronutrient composition in lactating mothers from suburban and urban Shanghai

Interactions between globular proteins and procyanidins of different degrees of polymerization

Seed protein amino acid composition of important local grain legumes Lupinus angustifolius L., Lupinus luteus L., Pisum sativum L. and Vicia faba L.

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