396. Chemical sterilization of dairy equipment. The bactericidal action of chlorine in the presence of protein

1949 ◽  
Vol 16 (3) ◽  
pp. 327-333 ◽  
Author(s):  
G. A. Cox ◽  
H. R. Whitehead
Keyword(s):  
Amino Acid ◽  
Skim Milk ◽  
Bactericidal Action ◽  
Chemical Sterilization ◽  
Dairy Equipment

1. Hypochlorite was allowed to react with glycine and with skim milk in various proportions, and the germicidal power of the resultant mixtures was determined.2. The results indicated that chloramino compounds formed by interaction of hypochlorite and protein or amino-acid have a definite but slow disinfecting action against Str. cremoris.3. The chloramino compounds did not appear to be more strongly germicidal at pH 9·5 than at pH 7·0 under the conditions of the experiments.

Fate of Organochlorine Pesticides During Processing of Milk into Dairy Products

1970 ◽  
Vol 53 (1) ◽  
pp. 127-139
Author(s):  
C F Li ◽  
R L Bradley ◽  
L H Schultz
Keyword(s):  
Dairy Products ◽  
Cheese Whey ◽  
Skim Milk ◽  
Cheddar Cheese ◽  
Bactericidal Action ◽  
Milk Products ◽  
Condensed Milk ◽  
Lactating Dairy Cows ◽  
Whole Milk ◽  
Spray Dried

Abstract Two lactating dairy cows per group were fed selected pesticides dissolved in organic solvents and mixed into a grain concentrate for a two week period. The reference pesticides used in this study were dieldrin; a mixture of heptachlor, DDT, and lindane; toxaphene; chlordane; endosulfan (Thiodan); and dicofol (Kelthane). The milk from these contaminated cows was collected and processed into the following dairy products: pasteurized whole milk, 30% cream, butter, spray-dried whole milk, condensed whole milk, sterilized condensed whole milk, and Cheddar cheese. The byproducts (skim milk, buttermilk, and Cheddar cheese whey) from manufacturing these products were also saved for subsequent analysis. The residues in these dairy products and byproducts were extracted, cleaned up, and analyzed by electron capture gas chromatography. The 30% cream, condensed milk, and pasteurized milk were analyzed at 0, 7, and 14 days and Cheddar cheese, spray-dried milk, butter, and sterilized condensed milk after storage for 0, 3, and 6 months. The results indicated that, in general, the pesticides used were very stable for ordinary dairy processing operations and remained essentially unchanged even after storage at refrigeration and room tempera-tures for 6 months. However, dieldrin, lindane, and chlordane showed a 27, 34, and 11% decrease, respectively, for spray-dried products and the concentration of dicofol showed a slight decrease in the sterilized condensed whole milk products, whereas the concentration of DDE extracted from the products stored 3 and 6 months was generally less than the amount extracted initially. In manufacturing Cheddar cheese, most of the pesticides showed some bacteriostatic or bactericidal action against starter microorganisms. Generally the pesticide residues were found in greater concentration (on a fat basis) in the skim milk, buttermilk, and whey than in products from which these were derived. This might be attributable to the affinity of the residues for the lipoprotein portion of the products. Concentrations of dieldrin and toxaphene increased slightly during storage of the milk and milk products, suggesting that a reorientation occurred.

Amino Acid and Secondary Structure Integrity of Sonicated Milk Proteins

2020 ◽  
Vol 73 (3) ◽  
pp. 170 ◽  
Author(s):  
Rachana Pathak ◽  
Thomas S. H. Leong ◽  
Gregory J. O. Martin ◽  
Muthupandian Ashokkumar
Keyword(s):  
Amino Acid ◽  
Secondary Structure ◽  
Acid Content ◽  
High Frequency ◽  
Structural Integrity ◽  
Skim Milk ◽  
Low Frequency ◽  
Amino Acid Content ◽  
Milk Proteins ◽  
Dairy Proteins

This study investigated the effect of low-frequency (20kHz) and high-frequency (414kHz) ultrasound treatment on the amino acid and secondary structural integrity of dairy proteins. Sonicated skim milk proteins were hydrolysed and analysed with reverse-phase high-performance liquid chromatography to investigate the amino acid content of the processed samples. It was successfully demonstrated that both low-frequency and high-frequency ultrasound did not adversely affect the amino acid content, even after prolonged extreme processing conditions (6h, 355kHz). This finding was supplemented with protein secondary structure data (Fourier-transform (FT)-IR secondary derivatives of the amide I band, 1700–1600cm−1) that showed that ultrasound was capable of causing structural modifications to the dairy proteins. This study shows that ultrasound can be used to influence protein–protein interactions in skim milk via alterations to the secondary structure without degrading the amino acids in the proteins.

scholarly journals Oxidation of an indicator amino acid by young pigs receiving diets with varying levels of lysine or threonine, and an assessment of amino acid requirements

1983 ◽  
Vol 50 (2) ◽  
pp. 391-399 ◽  
Author(s):  
Kyu-Il Kim ◽  
James I. Elliott ◽  
Henry S. Bayley
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino ◽  
Skim Milk ◽  
Linear Increase ◽  
Single Amino Acid ◽  
Dietary Level ◽  
Dietary Amino Acids ◽  
Young Pigs ◽  
Amino Acid Requirements

1. The catabolism of [14C]phenylalanine was used to indicate the effects of varying the dietary level of lysine and threonine on the retention of dietary amino acids by 2-week-old pigs receiving diets containing skim milk and a mixture of free amino acids.2. Reducing the dietary level of lysine from 16 to 12 g/kg had no influence on phenylalanine oxidation, reducing the lysine level from 12 to 11 then to 10 g/kg caused an almost linear increase in phenylalanine oxidation whereas further reduction to 9 or 8 g/kg resulted in a less-marked increase in phenylalanine oxidation. This showed that 12 g lysine/kg was required to maximize amino acid retention and indicated that lysine was conserved more effectively at low dietary concentrations than at dietary concentrations approaching the requirement.3. Reducing the dietary level of threonine from 8 to 6 g/kg had no influence on phenylalanine oxidation, whereas further reduction to 4 g/kg caused a linear increase in phenylalanine catabolism showing that 6 g threonine/kg was required to maximize amino acid retention.4. Reduction of the levels of lysine, threonine and methionine from the generous levels characteristic of a diet containing 240 g protein from skim milk/kg, to the requirement levels determined separately in the presence of the generous levels of all the other amino acids, resulted in a twofold increase in phenylalanine catabolism. This shows that the pig seems able to conserve limiting intakes of a single amino acid, but not if the intakes of two or three amino acids are limiting.

4 Protein and Amino Acid Concepts and Use in Swine Nutrition: Gary Allee’s Contributions to the Swine Industry

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 16-16
Author(s):  
Robert D Goodband
Keyword(s):  
Amino Acid ◽  
Skim Milk ◽  
Growing Pigs ◽  
Feeding Strategies ◽  
Cooperative Research ◽  
Swine Industry ◽  
Protein Amino Acid ◽  
Amino Acid Requirements ◽  
Novel Concept ◽  
Swine Nutrition

Abstract I was very fortunate to meet Gary Allee in 1984 when I began my M.S. degree at Kansas State University. I’ll remember Gary most in that he cared about people and truly wanted to serve humanity and make the world a better place through animal agriculture. He helped develop scholars, both nationally and internationally, that would be the future of our industry. Gary was proficient in seeking a solution to a problem and finding the experimental resources to explain it. Very early in his career, he helped verify the concept of a lysine:calorie ratio as a means of explaining the previously varied and inconsistent response to added fat in swine diets. Early research outlined the order of limiting amino acids in various feed ingredients. Gary’s research also focused on determining the nutritional value of protein sources for weanling pigs, such as dried whey, fish meal and dried skim milk that ultimately led to phase feeding strategies for early weaned pigs that are the backbone of our industry. Gary and his students determined lysine and other amino acid requirements for growing pigs and sows under field conditions. He helped elucidate the effects of low-protein, amino acid fortified diets under heat stress environments. As market weights increased, his research was instrumental in determining how to feed heavy weight pigs as well as those fed ractopamine. Gary grasped concepts and applied them into practical solutions in swine nutrition. He was a strong believer and leader in cooperative research among universities but also, at that time, a novel concept of university-industry partnerships. Those of us that can say they knew Gary Allee, are very fortunate and better because of it.

Effect of Intake of Different Dietary Protein Sources on Plasma Amino Acid Profiles at Rest and after Exercise

2012 ◽  
Vol 22 (6) ◽  
pp. 452-462 ◽  
Author(s):  
Louise M. Burke ◽  
Julie A Winter ◽  
David Cameron-Smith ◽  
Marc Enslen ◽  
Michelle Farnfield ◽  
...  
Keyword(s):  
Amino Acid ◽  
G Protein ◽  
Skim Milk ◽  
Area Under The Curve ◽  
Plasma Amino Acid ◽  
Pharmacokinetic Analysis ◽  
Liquid Meal ◽  
Protein Sources ◽  
Branched Chain ◽  
Protein Rich

The authors undertook 2 crossover-designed studies to characterize plasma amino acid (AA) responses to the intake of 20 g of protein. In Study 1, 15 untrained and overnight-fasted subjects consumed 20 g protein from skim milk, soy milk, beefsteak, boiled egg, and a liquid meal supplement. In Study 2, 10 fasted endurance-trained subjects consumed 20 g protein from a protein-rich sports bar at rest and after a 60-min submaximal ride. Plasma AA concentrations were measured immediately before and for 180 min after food ingestion using a gas-chromatography flame-ionization detection technique. A pharmacokinetic analysis was undertaken for profiles of total AAs (TAA), essential AAs, branched-chain AAs (BCAA), and leucine. Although area-under-the-curve values for plasma TAA were similar across protein sources, the pattern of aminoacidemia showed robust differences between foods, with liquid forms of protein achieving peak concentrations twice as quickly after ingestion as solid protein-rich foods (e.g., ~50 min vs ~100 min) and skim milk achieving a significantly faster peak leucine concentration than all other foods (~25 min). Completing exercise before ingesting protein sources did not cause statistically significant changes in the pattern of delivery of key AAs, BCAAs, and leucine apart from a 20–40% increase in the rate of elimination. These results may be useful to plan the type and timing of intake of protein-rich foods to maximize the protein synthetic response to various stimuli such as exercise.

scholarly journals Galactothermin, a reversibly heat-precipitable protein of human milk at neutral pH

1970 ◽  
Vol 118 (1) ◽  
pp. 181-186 ◽  
Author(s):  
A. L. Schade ◽  
R. W. Reinhart
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Human Milk ◽  
Skim Milk ◽  
Sedimentation Coefficient ◽  
Amino Acid Residues ◽  
Isolation And Purification ◽  
Neutral Ph ◽  
Polar Species ◽  
Ultracentrifugal Analysis

1. A protein, aggregating at body temperature and solubilizing when cooled, was isolated from fresh human milk at neutral pH and studied for some of its physical, chemical and immunological properties. The name `galactothermin' is proposed for this protein. 2. Isolation and purification of galactothermin involved casein removal from skim milk at pH4.64 followed by centrifugal fractionation of residual protein-containing solutions repeatedly heated and cooled between 40°C and 0°C at pH7.3. 3. The molecular weight by ultracentrifugal analysis and the minimum molecular weight by sum of amino acid residues were 11400 and 14000 respectively. The sedimentation coefficient s25,w was 1.05S and the diffusion coefficient was 7.15×10−7. Reversible aggregation is favoured by increase in protein concentration, ionic strength, temperature, time and approach to the isoionic point of 7.27 from either acidic or alkaline conditions. 4. Among the amino acid residues, proline predominates and non-polar species account for two-thirds of the total. Cysteine and cystine are absent. Analysis of galactothermin showed it to be essentially free of hexose, sialic acid, calcium and phosphate. 5. Galactothermin is antigenic in the rabbit as evidenced by the passive cutaneous anaphylaxis test. Single precipitin lines are produced in immunodiffusion tests. 6. By electrophoresis in polyacrylamide gel at pH4.0 only one sharp band is produced.

scholarly journals Metabolism of heat-damaged proteins in the rat

1971 ◽  
Vol 26 (2) ◽  
pp. 311-322 ◽  
Author(s):  
J. E. Ford ◽  
C. Shorrock
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Total Amino Acid ◽  
Carbohydrate Complex ◽  
Urinary Peptide

1. Freeze-dried cod muscle and casein were subjected to various conditions of heat treat-ment. Diets containing the different products, or the unheated materials, were given to a group of four adult male rats during successive 48 h periods, and urine was collected during the second 24 h of each 48 h period. A further collection of urine was made from the rats after they had been given protein isolated from heated skim-milk powder. The content and amino acid composition of the ‘peptide’ and ‘free amino acids’ in the urines were determined.2. Heat damage to the cod-fillet protein increased the total urinary excretion of peptide-bound amino acids, from 18·6 to 48·8 µmol/rat.d. The composition of the peptide also changed, and in particular there was a marked increase in lysine, from 2·98 to 20·30 µmol %. Three amino acids - lysine, aspartic acid and glutamic acid - together comprised nearly 70 % of the total amino acid residues. There was a corresponding increase in urinary excretion of free amino acids, from 53·7 to I 14·4 µmol/rat.d. The combined losses of lysine in urinary peptide and free amino acids were 1·5 % of the total lysine ingested, as against 0·3 % for the unheated cod fillet.3. The effects of similar heat treatment of casein on the composition of the urinary peptide and free amino acids were less marked. There was no increase in total urinary peptide excretion and there was a smaller increase in the lysine content of the peptide.4. In urine of rats given protein isolated from heated skim-milk powder, the peptide hydro-lysate was rich in lysine and in furosine, which together comprised 41 mol % of the total amino acid composition. These compounds were presumably formed, together with a smaller quantity of pyridosine, from lysine-carbohydrate complex in the urine. It is probable that, as compared with free lysine, the lysine-carbohydrate complex was absorbed relatively in-efficiently from the rat intestine.5. The findings are discussed in relation to the wider question of the metabolism of the ‚unavailable peptide’ that is released in the course of digestion of heat-damaged protein.

479. Studies on the biological value of the proteins (nitrogen) of dried skim milk: effects of the addition of certain amino-acids, of age of rat and of level of protein intake

1952 ◽  
Vol 19 (2) ◽  
pp. 216-225 ◽  
Author(s):  
K. M. Henry ◽  
S. K. Kon
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Protein Intake ◽  
Skim Milk ◽  
Adult Rats ◽  
Biological Value ◽  
Adult Rat ◽  
Amino Acid Requirements ◽  
Limiting Amino Acid ◽  
Control Milk

1. It has been shown that the biological value of undeteriorated dried skim milk is depressed to the same extent by the addition of 1·25% L-lysine as by the addition of 1·25% D-lysine. The latter is not used by the rat. It is therefore concluded that the added L-lysine is surplus to the animal's needs and that the apparent lowering of the biological value is due to excretion of the lysine in the urine.2. The slightly greater loss in the biological value of milk stored in air-pack compared with gas-pack was eliminated by the addition of 0·5% L-histidine to the former. Histidine is not a limiting amino-acid in the control or stored gas-pack milks for either young or adult rats.3. A lower biological value was found for the control milk with adult than with young rats at 4 and 8% levels of intake. No further lowering in the biological value of the stored milk, deficient in lysine, was observed with adult rats, the value obtained for this milk being independent of the age of the rat. These results are in keeping with the known lowered requirements of the adult rat for lysine.4. The significance of these findings in relation to the known amino-acid requirements of young and adult rats is discussed.

scholarly journals The effect of provision of the first-limiting amino acid, gastrointestinal microbial activity and the level of nitrogen intake on protein utilization and energy digestibility in rats

1985 ◽  
Vol 54 (3) ◽  
pp. 727-739 ◽  
Author(s):  
B. O. Eggum ◽  
R. M. Beames ◽  
K. E. Bach Knudsen
Keyword(s):  
Amino Acid ◽  
Microbial Activity ◽  
Protein Quality ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Protein Utilization ◽  
Protein Sources ◽  
Limiting Amino Acid ◽  
Soya Bean Meal

1. The present work with growing rats was undertaken to study the effect of protein quality, gastrointestinal microbial activity and the level of nitrogen intake on protein utilization and energy digestibiiity. The experiment involved a total of thirty-six dietary treatments in a 9 x 4 factorial design, with five rats per treatment. The thirty-six diets resulted from nine protein sources. Each diet was composed of a basal N-free mixture plus minerals and vitamins, with N sources added at the expense of the N-free mixture to provide 15.0 gN/kg dry matter (DM) in the first three protein-addition treatments and 30.0 gN/kg DM in the fourth protein-addition treatment. The nine protein sources were soya-bean meal, casein, wheat gluten, skim-milk powder, meat-and-bone meal, wheat bran, barley, wheat and cooked brown beans (Phaseolus vulgaris). The four formulations for each protein source incorporated the protein unsupplemented at 15.0 gN/kg DM, unsupplemented at 30.0 gN/kg DM, or supplemented at 15.0 gN/kg DM with the estimated first-limiting amino acid or the antibiotic Nebacitin.2. With all protein sources, the inclusion of the first-limiting amino acid had no effect on either protein or energy digestibility.3. The microbial activity in the digestive tract affected protein utilization and energy digestibility to a different degree depending primarily on the level and type of dietary fibre. True protein digestibility (TD) of skim-milk powder and brown beans, both rich in easily-fermentable energy, increased from 0.959 to 1.000 and from 0.680 to 0.777 respectively by the addition of Nebacitin. TD of the other protein sources was only marginally affected by the antibiotic treatment. Only with brown beans was the biological value (BV) markedly affected by Nebacitin with an increase from 0.482 to 0.557 by the treatment. Energy digestibility was significantly lower in rats given antibiotic with soya-bean meal, wheat bran, barley, wheat and brown beans.4. The effect of level of N intake on protein utilization was dependent on both protein quality and the fibre concentration of the diet. Protein sources with high BV were more affected than proteins of lower BV. It was concluded that TD is not always independent of dietary protein concentration.

scholarly journals Influence of dietary protein concentration on the oxidation of phenylalanine by the young pig

1986 ◽  
Vol 55 (3) ◽  
pp. 651-658 ◽  
Author(s):  
Ronald O. Ball ◽  
Henry S. Bayley
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
G Protein ◽  
Dietary Protein ◽  
Free Amino Acids ◽  
Free Amino ◽  
Crude Protein ◽  
Protein Concentration ◽  
Skim Milk ◽  
Intact Protein

1. Piglets were weaned at 3 d of age and reared to 2.5 kg on a liquid diet in which the protein was supplied by dried skim milk and a mixture of free amino acids. The oxidation of L-[l-14C]phenyIalanine was measured as an indication of the partition of amino acids between retention and catabolism in pigs (2.5 kg) offered meals containing vaned concentrations of crude protein (nitrogen x 6.25).2. The dietary protein concentration was varied either by increasing the inclusion of a mixture of free amino acids in a series of diets containing 100 g protein/kg from skim milk, or by increasing the level of inclusion of the skim milk in a series of diets containing the equivalent of 100 g protein/kg from the free amino acid mixture.3. The oxidation of phenylalanine was minimized by dietary protein concentrations of 240 and 258 g/kg for the diets containing increasing concentrations of free amino acids or skim milk respectively.4. These results show that a mixture of free amino acids is used more effectively than intact protein for promoting retention of essential amino acids.5. The recovery of radioactivity in expired carbon dioxide was inversely related to the recovery of radioactivity in liver tissue when the concentration of dietary crude protein was increased from deficient to adequate, demonstrating that the fractional oxidation of the indicator amino acid was inversely related to protein synthesis.

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