Availability of sulphur amino acids in protein foods

Miller, Eric L.; Hartley, A. W.; Thomas, Daisy

doi:10.1079/bjn19650050

Cited by 42 publications

(11 citation statements)

References 30 publications

(7 reference statements)

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“…The losses of 50 % of the cystine and 4 yo of the lysine from heating BPA at I I 5' for 27 h, as seen in Table I, were in good agreement with the results of Miller, Hartley & Thomas (1965)' who found a decrease of 60 % in cystine and 6 % in lysine in vacuumdried cod heated at 116' for 27 h. Other authors (reviewed by Miller, Hartley & Thomas, 1965) report similar findings; also that the presence of carbohydrates aggravates the loss of lysine (apart from its binding) and causes losses of arginine as well, even at temperatures around 1 0 0 ' . Heating BPA at 145' has caused some destruction of a large number of amino acids and again similar observations have been made with vacuum-dried cod (J. Bjarnason, unpublished results).…”

Section: Discussionsupporting

confidence: 86%

“…The 49 yo loss of the cys/z content in this case and similar losses reported by others for a variety of materials heated above 100' (cf. Miller, Hartley & Thomas, 1965) are perhaps significant evidence of an easy destruction of one half of the c y s /~ content according to equation The second stage (2) of the equation is not very clear. In some instances aldehydes have been reported as products (Schoberl & Eck, 1936) but, depending on the pH, dismutation of product B may also take place (Schoberl, 1933).…”

Section: Discussionmentioning

confidence: 99%

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Mechanisms of heat damage in proteins

1970

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I . Bovine plasma albumin (BPA) containing approximately 14 % moisture, when heated for 27 h at I I~O suffered an appreciable loss of cystine and a small loss of lysine; at 1 4 5~ all the amino acids except glutamic acid and those with paraffin side-chains, showed considerable losses. Isoleucine also showed some loss through racemization to alloisoleucine.2. BPA heated at I 1 5~ evolved H2S; at 145' other sulphur compounds were released as well, all coming from the breakdown of cystine. Possible mechanisms for this are discussed.3. Ammonia was also liberated from BPA heated at I I 5'. The degree of correlation of lysine binding in different proteins with ammonia liberation and amide changes has led us to suggest that the main reaction of €-amino lysine groups is with amide groups of asparagine and glutamine. Reaction of e-amino groups with carboxylic groups is thought to be less important. 4.Model experiments have shown that a reaction between amide groups and the e-amino group of lysine in proteins can occur at practical drying temperatures. .Reactions of the e-amino group of lysine with destruction products of cystine is also considered to be partially responsible for the lysine binding in heated proteins.It has long been known that the Maillard reaction between sugar aldehyde groups and the free amino acid groups of proteins can explain much of the damaging effect of heat on the protein quality of dried milk. However, heat damage can also occur if meat or fish products are heated excessively and these are essentially carbohydratefree. This too is accompanied by a loss of reactivity of the s-amino groups of lysine. Any oxidizing fat present may contribute carbonyl groups for a Maillard-type reaction but high-temperature heat damage cannot be considered as being just due to reaction with other non-protein compounds present, since it will occur to the same extent with pure protein preparations (Carpenter, Morgan, Lea & Parr, 1962). The changes also occur in an atmosphere of nitrogen as well as of oxygen (Carpenter, Ellinger, Munro & Rolfe, 1957).This study was designed to investigate the chemical changes which must occur during the heating of proteins as such, and be responsible for the nutritional damage. Because of the multiplicity of functional groups and of the many possible reactions which may occur during the heating, analytical work is difficult, and very little is known about what actually happens. Apart from amino acid destructions only the binding of lysine is well established. It has been suggested that the binding of lysine is caused by a reaction between the €-amino group of lysine and carboxylic groups in the protein and that such cross-linking reduces the nutritional availability of all the essential amino acids (cf. Mecham & Olcott, 1947 J. BJARNASON AND K. J. CARPENTER I970 E X P E R I M E N T A L Test materialsBovine plasma albumin (BPA) and lactalbumin were from the same source as in our first study (Bjarnason & Carpenter, 1969) and heated samples were prepared in the same way. The vacuum-d...

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Section: Discussionsupporting

confidence: 86%

Section: Discussionmentioning

confidence: 99%

Mechanisms of heat damage in proteins

1970

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“…However, at this temperature there seems to be a trend to lower the parameters considered. This result is in line with those reported by Miller et al 15 who found only a slight decrease of available lysine of cod muscle heated at 116" for 27 h.…”

Section: Freeze-supporting

confidence: 93%

Effect of drying temperature on quality of fish protein

1970

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Hake fillets (MerIuccius guyi) obtained by freeze-drying and oven-drying at 105" and 170% were analysed for their chemical composition and biological quality in relation to nitrogen and sulphur utilisation. Nitrogen utilisation was not affected by heating at 105". Net protein utilisation (NPU) (balance) values were 79 and 77 for the freeze-dried sample and that heated at 105", respectively. These results showed a good correlation with available lysine contents (8.6 and 8.3 g/100 g crude protein). However, sulphur utilisation suffered slight damage at 105".Heating at 170' for 6 h considerably reduced both nitrogen and sulphur utilisation. NPU fell from 79 to 51 and net sulphur utilisation decreased from 89 to 60. It is concluded that the intensity of heating during manufacture is a factor of critical importance in obtaining fish protein concentrate for either human or animal feeding.

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“…The Cys release data suggested that these residues are possibly located on the outer perimeter of the bean protein, and, thus, are more accessible to the proteases. The reactivity of Cys was reported by Miller et al (1965), who found that up to 60% of cystine was lost during the heating of cod muscle. Bender et al (1979) suggested that cystine appeared to be the amino acid in legume proteins that was most easily damaged.…”

Section: Resultsmentioning

confidence: 83%

Enzymatic Release of Peptides, Methionine and Cystine from Dry Beans Following Various Heat Treatments

Rayas‐Duarte

Satterlee

Romero

1988

Journal of Food Science

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Ground Great Northern and pinto bean (PhuseoZz~ vulgaris) samples were processed under varying conditions of time, temperature and pressure and then hydrolyzed in vifro using a mixture of trypsin, chymotrypsin and amino peptidase. The hydrolyzed samples were ultrafiltrated and the peptides (c 10,000 daltons) were collected and analyzed for their sulfur amino acid content (methionine, cysteine, and cystine). From 48% to 100% of the cysteine/cystine residues in the protein were released after 6 hr of enzymatic hydrolysis, whereas only 10% to 40.2% of the methionine residues were released during the same time period. The maximum rate of peptide release occurred at 3 hr of proteolysis, while the maximum rate of methionine and cysteine release occurred at 2 hr of proteolysis.

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Availability of sulphur amino acids in protein foods

Cited by 42 publications

References 30 publications

Mechanisms of heat damage in proteins

Mechanisms of heat damage in proteins

Effect of drying temperature on quality of fish protein

Enzymatic Release of Peptides, Methionine and Cystine from Dry Beans Following Various Heat Treatments

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