scholarly journals Studies on the composition of food

1966 ◽  
Vol 20 (4) ◽  
pp. 747-755 ◽  
Author(s):  
N. Chamberlain ◽  
T. H Collins ◽  
G. A. H Elton ◽  
Dorothy F Hollingsworth ◽  
D. B Lisle ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Nicotinic Acid ◽  
High Speed ◽  
Protein Quality ◽  
Dehydroascorbic Acid ◽  
Pilot Scale ◽  
Mechanical Agitation ◽  
Protein Utilization ◽  
Net Protein ◽  
Made In

1. The Chorleywood Bread Process is a new method of making bread in which the 2–4 h of bulk fermentation of the dough normal in breadmaking is replaced by a few minutes of intense mechanical agitation to a controlled degree in special high-speed mixers. It is now being used to make over 30% of British bread. 2. Bread was made in a commercial bakery from two white flours by the Chorleywood Bread Process and a conventional method. 3. Both the bread and flours were analysed for moisture, protein, ash, fat, carbohydrate (by difference), thiamine, nicotinic acid and ascorbic acid. 4. More bread was made by the two processes from two other flours in a pilot-scale bakery. These breads and flours were used to determine net protein utilization values. 5. It was concluded that bread made by the Chorleywood Process cannot be distinguished from conventional bread in its content of protein, fat, ash and nicotinic acid, and in protein quality as indicated by its net protein utilization value. This was true for two grades of flour. In these tests the contents of thiamine and moisture were slightly higher and of carbohydrate slightly lower in Chorleywood than in conventional bread. No ascorbic or dehydroascorbic acid could be detected in any of the bread.

Determination of Total Vitamin C by Ion Exclusion Chromatography with Electrochemical Detection

1989 ◽  
Vol 72 (4) ◽  
pp. 681-686
Author(s):  
Hie-Joon Kim
Keyword(s):  
Ascorbic Acid ◽  
Sulfuric Acid ◽  
Vitamin C ◽  
Retention Time ◽  
Acid Content ◽  
High Speed ◽  
Reference Electrode ◽  
Dehydroascorbic Acid ◽  
Total Vitamin

Abstract A rapid and sensitive liquid chromatographic method for determination of total vitamin C in foods and beverages is described. Ascorbic acid and dehydroascorbic acid are extracted with sulfuric acid solution, and the dehydroascorbic acid in the extract is reduced to ascorbic acid by dithiothreitol at pH 7. The reduction is complete in 2 min at room temperature. The resulting total ascorbic acid is separated on an anion exclusion/high speed column with 20mM sulfuric acid as eluant and detected amperometrically with a platinum electrode operating at +0.6-0.8 V vs Ag/AgCl reference electrode. Dithiothreitol (retention time, 3.2 min) does not interfere with the separation and detection of ascorbic acid (retention time, 1.3 min). The dehydroascorbic acid content can be estimated as the difference in ascorbic acid content measured with and without reduction by dithiothreitol. The completeness of the reduction was demonstrated by purposely allowing the oxidation of ascorbic acid in the food extract and determining the total vitamin C after reduction. The determinations of vitamin C content in selected foods and beverages were in good agreement with the expected values. Total analysis time for vitamin C is 10 min and the detection limit is 0.1 ng. The method is specific for vitamin C, and interference by other food constituents is minimal.

Stability of Ascorbic Acid in Reconstituted Frozen Orange Juice

1977 ◽  
Vol 40 (9) ◽  
pp. 584-585 ◽  
Author(s):  
PRISCILLA B. HORTON ◽  
SHERMAN R. DICKMAN
Keyword(s):  
Ascorbic Acid ◽  
Orange Juice ◽  
Phosphate Buffer ◽  
High Speed ◽  
Room Temperature ◽  
Phosphate Buffer Solution ◽  
Dehydroascorbic Acid ◽  
Temperature Stability ◽  
Buffer Solution

The sum of ascorbic acid and dehydroascorbic acid (physiologically available ascorbic acid), in reconstituted orange juice was remarkably stable over a 2-week period, both at 4 C and at room temperature. Stability was not affected by the aerating effect of blendorizing at high speed for 2 min. Stability was only partially due to the pH of orange juice, since available ascorbic acid declined more rapidly in a phosphate buffer solution at the same pH.

scholarly journals A new biological method for estimating food protein nutritive value

1969 ◽  
Vol 23 (3) ◽  
pp. 491-495 ◽  
Author(s):  
Shoshana Mokady ◽  
S. Vila ◽  
G. Zimmermann
Keyword(s):  
Nutritive Value ◽  
Protein Quality ◽  
Wheat Gluten ◽  
Protein Isolate ◽  
Food Protein ◽  
Protein Utilization ◽  
Nitrogen Intake ◽  
New Criterion ◽  
Net Protein

1. A new method has been devised for the nutritional evaluation of food protein quality. The method is analogous to the classical determination of net protein utilization (NPU). The suggested new criterion, the protein utilization by the liver (LPU), expresses the amount of food nitrogen ‘retained’ in the liver as a percentage of the food nitrogen intake.2. Five different foods, casein, soya-bean protein isolate, maize gluten, wheat gluten, cottonseed meal alone or with supplements of amino acids, a total of thirteen samples, were tested for LPU and NPU in groups of six rats. The correlation coefficient between values for LPU and NPU for all seventy-eight rats was +0.85 and was highly significant.

scholarly journals Routine Analysis of Ascorbic Acid in Citrus Juice Using Capillary Electrophoresis

2001 ◽  
Vol 84 (3) ◽  
pp. 987-992 ◽  
Author(s):  
Paul F Cancalon
Keyword(s):  
Ascorbic Acid ◽  
Capillary Electrophoresis ◽  
Vitamin C ◽  
High Speed ◽  
Ethylenediaminetetraacetic Acid ◽  
Internal Standard ◽  
Dehydroascorbic Acid ◽  
Sodium Borate ◽  
Internal Standard Method ◽  
Citrus Juice

Abstract A procedure to monitor citrus juice samples was established to quantitate vitamin C by capillary electrophoresis using a previously developed method. Dilution and filtration were the only preparation requirements and separation was achieved with an uncoated capillary using a 35mM sodium borate buffer (pH 9.3) containing 5% (v/v) acetonitrile at 21 kV and 23°C. Detection was performed by high speed scanning between 200 and 360 nm. From the multiwave length scan, the electropherogram at 270 nm was extracted and used to quantitate ascorbic acid. The ascorbic acid concentration was calculated with an internal standard method, with ferulic acid as internal standard. The level of ascorbic acid during analysis was stabilized with ethylenediaminetetraacetic acid and dithiothreitol was used to reduce dehydroascorbic acid to ascorbic acid to estimate the total vitamin C level. Results were similar to those obtained by liquid chromatography and the method is now used to determine routinely the level of ascorbic acid in citrus juices.

The requirement of the gilthead seabream (Sparus aurata L.) for nicotinic acid

1995 ◽  
Vol 61 (2) ◽  
pp. 437-443 ◽  
Author(s):  
P. C. Morris ◽  
S. J. Davies
Keyword(s):  
Nicotinic Acid ◽  
Sparus Aurata ◽  
Relative Content ◽  
Hepatosomatic Index ◽  
Gilthead Seabream ◽  
Lower Plasma ◽  
Protein Utilization ◽  
Lower Plasma Glucose ◽  
Net Protein ◽  
Line Analysis

AbstractSemi-purified diets were used to determine the nicotinic acid requirement of the gilthead seabream, Sparus aurata. Vitamin losses during food manufacture were minimal resulting in dietary levels which were close to the declared content. Dietary nicotinic acid contents of 52·21 mg/kg and below resulted in sub-optimum growth, reduced food efficiency and poor values for apparent net protein utilization. Diets containing less than 28·67 mg/kg gave a low proportion of carcass lipid concomitant with an elevation in the relative content of carcass moisture. Although gross deficiency symptoms were not observed, a reduced hepatosomatic index and a slightly lower plasma glucose concentration were detected amongst the fish given diets supplemented with nicotinic acid at the level of 25 mg/kg or less. Based upon the results of broken line analysis and data derived by modelling the weight gain of the fish, the nicotinic acid requirement of Sparus aurata fingerlings lies between 63 and 83 mg/kg of diet or 1·57 to 2·07 µg/kg body weight per day.

Paper 23: The Collision of Drops with Dry and Wet Surfaces in an Air Atmosphere

1969 ◽  
Vol 184 (7) ◽  
pp. 57-63
Author(s):  
G. J. Parker ◽  
E. Bruen
Keyword(s):  
Steam Turbine ◽  
High Speed ◽  
Size Range ◽  
Drop Surface ◽  
Wet Steam ◽  
Air Atmosphere ◽  
Made In

This paper describes an investigation into the behaviour of drops which impinge upon dry and wet surfaces. This is of particular interest in the context of the wet steam turbine. Two approaches have been made in the studies; these are: (1) Drops were made to impinge normally on to various types of dry, stationary surfaces. The drops were in the size range 300–1500 μm diameter with velocities of 2–9 m/s. (2) Drops were made to impinge on to surfaces moving with considerable velocity at right angles to the motion of the drop. Surface velocities ranged up to 45 m/s. The latter study is of direct interest for the splashing of drops on turbine casings at small glancing angles, as occurs near drainage belts. Analysis of the mechanisms involved is made from the records of high-speed ciné photography.

scholarly journals Concentration-Dependent Antioxidant/Pro-Oxidant Activity of Ascorbic Acid in Chickens

2012 ◽  
Vol 66 (6) ◽  
pp. 256-260
Author(s):  
Nadežda Berzina ◽  
Jurijs Markovs ◽  
Mirdza Apsīte ◽  
Svetlana Vasiļjeva ◽  
Galina Smirnova ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Ascorbic Acid ◽  
Cadmium Concentration ◽  
Dehydroascorbic Acid ◽  
Cadmium Accumulation ◽  
Suppressive Effect ◽  
High Dose ◽  
Dependent Manner ◽  
Treatment Groups ◽  
Liver And Kidney

The effects of ascorbic acid supplementation on biomarkers of oxidative stress, cadmium accumulation in organs, immune system activity and kidney function in chickens were investigated. The treatment groups of chickens were fed either plain diet or diet supplemented with ascorbic acid at 100, 500, 1000 and 2000 mg/kg for four weeks. Liver and kidney tissues were assayed for cadmium concentration, and the hepatic levels of ascorbic acid and dehydroascorbic acid (DHAA; the oxidised form), malondialdehyde, glutathione, activity of glutathione peroxidase, blood serum uric acid, creatinine, lysozyme and circulating immune complexes were measured. Supplementation with a high dose of ascorbic acid (1000 and 2000 mg/kg in the diet) caused an imbalance between pro-oxidative and antioxidative activities, and induced a suppressive effect on innate immunity. The results suggest that oxidative stress compromises renal function. We observed that ascorbic acid increased cadmium accumulation in a dose-dependent manner.

Sign in / Sign up

Export Citation Format

Share Document