Hjemmelavet proteinbarer!?

[Styrken]

Nu er der efterhånden lavet endel indlæg omkring hjemmelavede proteinbarer.

Har læst 2 emner hvor størstedelen siger at det ikke kan lade sig gøre at putte proteinpulvert i ovnen, så vil det fordampe! - og om om at wheyprotein ikke dur men noget andet dur.

Så har jeg læst 4 emner hvor folk overposter med deres hjemmelavede proteinbar-opskrifter...

Kan man lave sine egne barer, og putte proteinen i ovnen?

[MaxPower]

proteinpulveret fordamper ikke, men det skulle denaturere. Det du nok har læst er at æggeprotein skulle egne sig bedre til bagning.

Jeg har dog stadig ikke helt fået klarlagt hvad denatureringen betyder mht. optagelsen og kvaliteten af proteinet.

[Styrken]

Ja det er rigtigt. Men der er ikke kommet et klart svar på, om det kan betale sig at lave de proteinbarer?

- Om når det denaturerer, kan det så stadig bruges som en god proteinkilde?

- har det nogen betydning at det detonerer?

- Og vil det ikke denaturere hvis det ikke er whey?

[MaxPower]

- har det nogen betydning at det detonerer?

big-whey-bada-boom

[Niels Weldingh]

Jeg spurgte lige hurtigt to af mine gamle lærere (kemi og biologi) i mandags hvad det betød for optagelsen, at protein blev varmet op og blev denatureret. De sagde begge to at det ikke betød noget for optagelsen at protein denaturerede, men biologilægeren var ikke helt sikker så hun sagde at hun lige ville undersøge det.

[TF vol. II]

:4thumbup:

[Styrken]

- har det nogen betydning at det detonerer?

big-whey-bada-boom

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I see

[Sputnik]

Jeg har kigget lidt på PubMed for at finde noget om ernæringsmæssige effekter af varmebehandling af proteiner. Det virker som om den væsentligste forringelse skyldes Maillard reaktionen, hvor især aminosyren lysin reagerer med sakkarider og danner fx fruktoselysin, laktuloselysin og maltuloselysin. Andre effekter af varmebehandlingen er dannelse af protein-polyfenoler og heterocykliske aminosyrer, racemisering af L-aminosyrer til D-aminosyrer og reaktioner, hvor aminosyren alanin indgår og danner fx dehydroalanin og lysinoalanin.

I artiklen af Rérat et al. (2002) varmebehandles (”roller-dried”) skummetmælkspulver således at 50 % af lysinen er blokeret i form af den bioutilgængelige laktuloselysin. De konkluderer at andre omdannelser ikke har fundet sted på grund af den kortvarige opvarmning. Absorptionen af aminosyrerne var signifikant mindre for lysin (-60 %) og alanin (-17 %) (p < 0,05). Et lille fald i nedbrydeligheden af de absorberede aminosyrer (-6 %) var også set. Da blokeringsgraden i forsøget er noget højere end i fødevarer konkluderer de, at den primære konsekvens af varmebehandlingen af proteinet er et tab af lysin.

Eur J Nutr. 2002 Feb;41(1):1-11.

Nutritional and metabolic consequences of the early Maillard reaction of heat treated milk in the pig. Significance for man.

Rerat A, Calmes R, Vaissade P, Finot PA.

CRJ-INRA, Jouy-en-Josas, France.

BACKGROUND: During the processing of foods, the Maillard reaction may occur contributing to altering the nutritional value of proteins. In dairy products the formation of lactuloselysine reduces the availability of lysine but the effects on the other nutrients are not very well known. AIM OF THE STUDY: Determination of the consequences of a high level of lactuloselysine in milk on the bioavailability of skim milk nutrients and the kinetics of their appearance in the portal blood and of their urinary and faecal excretions and extrapolation to lower heat treatments and to man, using the pig model. METHODS: Sub-adult pigs were fitted, under anaesthesia, with permanent catheters in the portal vein, carotid artery and urethra, and with an electromagnetic flow probe around the portal vein. Each animal was successively fed with two experimental meals containing an equal amount of dried skim milk (SM), either lyophilised or heat treated to obtain an intense Maillard reaction, (M-SM) resulting in a 50% lysine blockage. Portal and arterial concentrations and flux of individual amino acids (AA), glucose, galactose and fructoselysine were measured for a period of 12h after the meals. Lysine, fructoselysine and AA excreted in the urine and faeces within 72h were also determined. RESULTS: In M-SM containing 50% blocked lysine, no other AA was chemically modified. Fructoselysine appeared in the portal blood very late compared to amino acids resulting from a very slow release and corresponded to 8.2 and 18.6% of the ingested amount after 12 and 72h, respectively. Significant changes of the appearance in the portal blood were observed only for lysine (-60%), alanine (-17%) and cystine (+37%). A small decrease in the digestibility of most AA during the same period was observed, which was significant after 48h for lysine, phenylalanine, cystine, aspartic acid, glycine and total AA (-6%). CONCLUSION: It was confirmed that lactuloselysine was not bioavailable. The loss in protein nutritive value was mainly due and proportional to the deterioration of lysine and, to a lesser extent, to the decrease in the digestibility of some essential AA. Taking into account the very high level of lactuloselysine in the M-SM sample studied, it may be concluded that in common foods such as milk, infant formulas, biscuits, bread, pasta, containing lower levels of blocked lysine, the nutritional loss is primarily due to the loss of lysine and to a less extent to the decrease in the digestibility of other essential AA.

PMID: 11990002 [PubMed - indexed for MEDLINE]

Desværre står der ikke præcist hvordan skummetmælkspulveret blev behandlet i artiklen, så det er ikke muligt at lave en direkte sammenligning med fx bagning, som jo er trådens emne. Det virker dog som om, at man kan konkludere, at lysin er den mest varmefølsomme aminosyre efterfulgt af alanin.

Andre artikler, der handler om ernæringsmæssige effekter af varmebehandling af proteiner:

Bibl Nutr Dieta. 1989;(43):140-55.

Protein reactions during food processing and storage--their relevance to human nutrition.

Erbersdobler HF.

Institut fur Humanernahrung und Lebensmittelkunde der Christian-Albrechts Universitat zu Kiel, FRG.

The main reactions of protein components during food processing and storage were presented and discussed. Since most data are available from the reactions of lysine with other food components these results are mainly demonstrated. Using furosine as indicator the formation and presence of the early Maillard products fructoselysine, lactuloselysine or maltuloselysine in several food systems was measured. Also lysinoalanine is mentioned. A further, recently detected compound, N-epsilon-carboxymethyllysine, appears to be also of biological and technological interest. Several foods contained up to 2,000 ppm carboxymethyllysine in the protein. Experiments with rats and human volunteers have shown that the fructoselysine moiety is poorly digested and absorbed and apparently not metabolized but soon excreted via the kidneys. While being on a normal diet the 20 volunteers excreted 3.3 +/- 1.4 mg fructoselysine per day, which indicates that our food contains always some of these products. Less is known about the absorption and excretion of lysinoalanine or carboxymethyllysine. These reactions cause undoubtedly drastic reductions in the availability of lysine and in this way also in the biological value (and in higher grades of damage additionally of the protein digestibility). Moreover some adverse effects-e.g. interference with the transport of other amino acids, increased renal losses of zinc and copper and cytomegaly in the pars recta of the outer medullary stripe of rat kidneys-were observed in connection with the products of the early or advanced Maillard reaction. These partially negative influences, however, appear not to be of significance under practical conditions. Compounds, possibly carcinogenic, are some degradation products of tryptophan and imidazoquinoline- or imidazoquinoxalin-2-amine derivatives (IQ compounds), which are formed during broiling of meat or fish by the reaction of Maillard products (pyridines or pyrazines and aldehydes) with creatinine.

PMID: 2730549 [PubMed - indexed for MEDLINE]

Forum Nutr. 2003;56:350-2. Related Articles, Links 

Nutritional consequences of food processing.

Friedman M.

Western Regional Research Center, Agricultural Research Service, USDA, Albany, California 94710, USA. [email protected]

A variety of methods are used to process foods: if they are not edible, to render them so; to permit storage; to alter texture and flavor; to destroy microorganisms and other toxins. These methods include heating (baking, cooking, frying, microwaving), freezing, and high pH. It is a paradox of nature that the processing of foods can improve, nutrition, quality, and safety; yet, occasionally these processing alternatives can lead to the formation of anti-nutritional and toxic compounds. These multi-faceted consequences of food processing result from molecular interactions among nutrients and with other food ingredients, both natural and added. This paper outlines the following aspects of processing-induced formation of novel food ingredients and the resulting consequences for nutrition: protein-polyphenol and protein-carbohydrate enzymatic and non-enzymatic browning reactions; formation of heterocyclic amines in meat; inactivation of soybean inhibitors of digestive enzymes; formation of lysinoalanine and D-amino acids in food proteins; and the stability of phenolic compounds to high pH. Possible approaches to prevent the formation of deleterious food ingredients are also addressed.

PMID: 15806931 [PubMed - in process]

J Agric Food Chem. 1999 Apr;47(4):1295-319.

 

Chemistry, biochemistry, nutrition, and microbiology of lysinoalanine, lanthionine, and histidinoalanine in food and other proteins.

Friedman M.

Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Albany, CA 94710, USA.

Heat and alkali treatments of foods, widely used in food processing, result in the formation of dehydro and cross-linked amino acids such as dehydroalanine, methyldehydroalanine, beta-aminoalanine, lysinoalanine (LAL), ornithinoalanine, histidinoalanine (HAL), phenylethylaminoalanine, lanthionine (LAN), and methyl-lanthionine present in proteins and are frequently accompanied by concurrent racemization of L-amino acid isomers to D-analogues. The mechanism of LAL formation is a two-step process: first, hydroxide ion-catalyzed elimination of H(2)S from cystine and H(2)O, phosphate, and glycosidic moieties from serine residues to yield a dehydroalanine intermediate; second, reaction of the double bond of dehydroalanine with the epsilon-NH(2) group of lysine to form LAL. Analogous elimination-addition reactions are postulated to produce the other unusual amino acids. Processing conditions that favor these transformations include high pH, temperature, and exposure time. Factors that minimize LAL formation include the presence of SH-containing amino acids, sodium sulfite, ammonia, biogenic amines, ascorbic acid, citric acid, malic acid, and glucose; dephosphorylation of O-phosphoryl esters; and acylation of epsilon-NH(2) groups of lysine. The presence of LAL residues along a protein chain decreases digestibility and nutritional quality in rodents and primates but enhances nutritional quality in ruminants. LAL has a strong affinity for copper and other metal ions and is reported to induce enlargement of nuclei of rats and mice but not of primate kidney cells. LAL, LAN, and HAL also occur naturally in certain peptide and protein antibiotics (cinnamycin, duramycin, epidermin, nisin, and subtilin) and in body organs and tissues (aorta, bone, collagen, dentin, and eye cataracts), where their formation may be a function of the aging process. These findings are not only of theoretical interest but also have practical implications for nutrition, food safety, and health. Further research needs are suggested for each of these categories. These overlapping aspects are discussed in terms of general concepts for a better understanding of the impact of LAL and related compounds in the diet. Such an understanding can lead to improvement in food quality and safety, nutrition, microbiology, and human health.

Publication Types:

Review

PMID: 10563973 [PubMed - indexed for MEDLINE]

J Nutr Sci Vitaminol (Tokyo). 1990;36 Suppl 1:S57-69.

Influence of processing on protein quality.

Mauron J.

University of Fribourg, Switzerland.

In the first part the reactions and interactions of protein with macroconstituents of our food during processing are exposed from the chemical point of view. The reactions involving only protein (formation of isopeptides, of lysinoalanine, racemization) and the interactions with carbohydrates (Maillard reaction), oxidized lipids and polyphenols are briefly presented. Emphasis is put on the Maillard reaction since it is the most frequent reaction occurring during food processing and storage. The key compound rendering lysine unavailable in processed and stored foodstuffs in N epsilon-fructoselysine (FL). Its oxidative degradation product, N epsilon-carboxymethyllysine (CML) is found in variable but significant amounts in heat processed proteins. An interesting newer finding is that tryptophan can participate in a Maillard reaction with its indole-NH-group. In the second part an overview is given on the impact these reactions have on the two components of protein nutritive value, namely digestibility and biological value. Again, most examples will be related to the Maillard reaction. Protein digestibility may be reduced by the modification of the protein molecule (blocking of active amino acid side-chains, establishment of crosslinks) or by the formation of compounds that inhibit digestive enzymes. (Inhibition of aminopeptidase by an advanced Maillard derivative of lysine). Biological value may be diminished by the loss of essential amino acids and/or their reduced specific availability. Ion-exchange chromatography of the protein hydrolyzate is the method of choice to determine amino acid losses. It also provides some clues for the type of processing damage by the presence of unusual amino acids in the chromatogramme (e.g. furosine, lysinoalanine). Global amino acid bioavailability is defined. It is of a complex nature and can only be truely determined in a bioassay in the animal. Specific availability of an amino acid is linked to particular structural features. Thus, specific lysine availability is determined by the presence of a free or "reactive" epsilon-amino group. This is the basis for the analytical methods for available lysine. In the third part, the practical application of this knowledge to processed foods is shown using milk and vegetable protein as examples. Figures for the reduction in available lysine (blocked lysine) in different milk products processed according to conventional procedures are given and discussed. More subtile effects of milk processing on milk digestibility and stomach emptying are mentioned. The effects on protein nutritional value of extrusion-cooking of legume seeds and cereal flours are, then, presented.(ABSTRACT TRUNCATED AT 250 WORDS)

PMID: 2081988 [PubMed - indexed for MEDLINE]

J Agric Food Chem. 1999 Sep;47(9):3457-79.

 

Chemistry, nutrition, and microbiology of D-amino acids.

Friedman M.

Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 800 Buchanan Street, Albany, California 94710, USA. [email protected]

Exposure of food proteins to certain processing conditions induces two major chemical changes: racemization of all L-amino acids to D-isomers and concurrent formation of cross-linked amino acids such as lysinoalanine. Racemization of L-amino acids residues to their D-isomers in food and other proteins is pH-, time-, and temperature-dependent. Although racemization rates of the 18 different L-amino acid residues in a protein vary, the relative rates in different proteins are similar. The diet contains both processing-induced and naturally formed D-amino acids. The latter include those found in microorganisms, plants, and marine invertebrates. Racemization impairs digestibility and nutritional quality. The nutritional utilization of different D-amino acids varies widely in animals and humans. In addition, some D-amino acids may be both beneficial and deleterious. Thus, although D-phenylalanine in an all-amino-acid diet is utilized as a nutritional source of L-phenylalanine, high concentrations of D-tyrosine in such diets inhibit the growth of mice. Both D-serine and lysinoalanine induce histological changes in the rat kidney. The wide variation in the utilization of D-amino acids is illustrated by the fact that whereas D-methionine is largely utilized as a nutritional source of the L-isomer, D-lysine is totally devoid of any nutritional value. Similarly, although L-cysteine has a sparing effect on L-methionine when fed to mice, D-cysteine does not. Because D-amino acids are consumed by animals and humans as part of their normal diets, a need exists to develop a better understanding of their roles in nutrition, food safety, microbiology, physiology, and medicine. To contribute to this effort, this multidiscipline-oriented overview surveys our present knowledge of the chemistry, nutrition, safety, microbiology, and pharmacology of D-amino acids. Also covered are the origin and distribution of D-amino acids in the food chain and in body fluids and tissues and recommendations for future research in each of these areas. Understanding of the integrated, beneficial effects of D-amino acids against cancer, schizophrenia, and infection, and overlapping aspects of the formation, occurrence, and biological functions of D-amino should lead to better foods and improved human health.

Publication Types:

Review

PMID: 10552672 [PubMed - indexed for MEDLINE]