410. The oxidation of ascorbic acid in dairy products

1950 ◽  
Vol 17 (1) ◽  
pp. 54-65 ◽  
Author(s):  
J. E. Allan
Keyword(s):  
Ascorbic Acid ◽  
Cold Storage ◽  
Dairy Products ◽  
Room Temperature ◽  
Ferric Iron ◽  
Storage Temperature ◽  
Chloride Ion ◽  
Inhibitory Effect ◽  
Titration Procedure

1. The determination of ascorbic acid in butter by the usual macrotitration method was found to be impossible because this substance rapidly became oxidized while the butter was being melted, so that only about half could be recovered.2. A simple micro-titration procedure enabled more reliable results to be obtained, but the loss of ascorbic acid from smaller samples could not be reduced below about 10% under the most favourable conditions.3. Kinetic experiments have been carried out on butter serum and buttermilk to which ascorbic acid had been added, and from the results it has been deduced that the oxidation of ascorbic acid takes place by three distinct concomitant reactions: one catalysed by the original copper, one catalysed by added copper, and one catalysed by added ferric iron.4. It has been calculated that in an unsalted butter of normal metallic content half the ascorbic acid would be oxidized in about 12 hr. at cold storage temperature ( – 13° C). At this temperature, 0·1 p.p.m. of added copper is about twenty times as effective a catalyst as 1·0 p.p.m. of added iron. At room temperature the corresponding half-oxidation time would be about 2 hr., and here 0·1 p.p.m. of added copper is about four times as active as 1·0 p.p.m. of added iron. In salted butter the inhibitory effect of the chloride ion would increase these times somewhat.5. The chemical state in which copper and iron exist in milk and related products has been discussed, especially in relation to the kinetic results obtained.

scholarly journals Evaluasi Penyimpanan Spermatozoa Ayam Pada Suhu 5⁰C, 26⁰C Dengan Pengencer Infuse NaCl, Glukosa 5% dan 10%

2021 ◽  
pp. 10-19
Author(s):  
Asnawi Asnawi ◽  
Maskur Maskur ◽  
Adji Santoso Dradjat
Keyword(s):  
Cold Storage ◽  
Room Temperature ◽  
Storage Temperature ◽  
Room Temperature Storage ◽  
C Storage ◽  
Better Than ◽  
Temperature Storage

The purpose of this study were to compare the quality of spermatozoa stored at 26⁰C, 5⁰C using diluents of NaCl, 10% glucose and 5% glucose. The spermatozoa of a rooster was collected and divided into 6 parts, each 2 tubes diluted in a ratio of 1:1 using NaCl, Glucose5% and Glucose 10%, then each 3 tubes with different diluents were stored at 26⁰C and 5⁰C. Observations of motility, viability and abnormalities of spermatozoa were carried out half an hour, 1 hour after dilution, followed every 2 hours until the ninth hours. The results showed that spermatozoa stored for 9 hours at a temperature of 26⁰C with a physiological diluent of NaCl, 10% Glucose and 5% Glucose each were different (P, < 0.05) with motility 50 ± 0.0%, 42 ± 10.95. % and 34±8.94%, respectively. At storage temperature of 5⁰C for 9 hours, physiological NaCl, 10% glucose and 5% glucose were significantly different (P<0.05) with motility 58.00±10.95%, 46.00±8.94% and 38.00±, respectively. 10.95% in a row. The viability of spermatozoa at 26⁰C storage with 5% glucose diluent was better than 10% glucose and physiological NaCl (P<0.05), 58.93±1.27%, 42.93±1.48% and 33.43±1.27% , while the physiological NaCl diluent and 10% glucose were not significantly different (P>0.05). At 5⁰C storage the viability of spermatozoa in the three diluents was not significantly different, with values of Glucose 10%, Glucose 5% and physiological NaCl 52.57±5.15%, 52.21±5.02% and 48.14±8.09%, respectively. Spermatozoa abnormalities at storage temperature 26⁰C and 5⁰C for 9 hours using physiological NaCl diluent, 5% glucose and 10% glucose, were not significantly different and varied between 5 to 10%. Finally, it can be concluded that at room temperature storage less than 4 hours the quality of spermatozoa was better with 5% glucose diluent, while for cold storage beyond 4 hours the quality of spermatozoa with NaCl diluent was higher

scholarly journals Ethylene production in apple infected by Gleosporium album Ostrw. at cold storage

2011 ◽  
Vol 33 (No. 1) ◽  
pp. 1-6
Author(s):  
J. Goliáš ◽  
A. Němcová ◽  
P. Mýlová
Keyword(s):  
Cold Storage ◽  
Ethylene Production ◽  
Canonical Correlation ◽  
Storage Temperature ◽  
Apple Fruit ◽  
Gas Analysis ◽  
Light Hydrocarbons ◽  
High Affinity ◽  
Headspace Gas

In ten cultivars of apple fruit, ethylene production expressed in &mu;l/kg/h was determined. The cultivar Resista exhibited a higher ethylene production and can be differentiated from other cultivars. The production ranged from 4.2 &plusmn; 0.58 &mu;l/kg/h in the case of Meteor cv. up to 131.6 &plusmn; 5.5 &mu;l/kg/h in Resista cv. Infected fruit of Topaz cv. had a lower ethylene production at cold storage temperature (3&deg;C) than some healthy fruit. All examined cultivars can be divided into three clusters. Discriminant analysis and canonical correlation analysis of the examined apple fruit led to the determination of healthy and infected fruit. Values of ethylene production were analyzed on intact fruit by using headspace gas analysis by CGC with thermal desorption technique. Carbosieve G was chosen as the adsorbent material for the traps due to its relatively high affinity for light hydrocarbons such as ethylene. For a full trap of ethylene in the enrichment column the sufficient amount of percolating gas is about 0.3 l. &nbsp;

scholarly journals A Single-Solution Method for the Determination of Soluble Phosphate in Sea Water

1958 ◽  
Vol 37 (1) ◽  
pp. 9-14 ◽  
Author(s):  
J. Murphy ◽  
J. P. Riley
Keyword(s):  
Ascorbic Acid ◽  
Room Temperature ◽  
Solution Method ◽  
Sea Water ◽  
Ammonium Molybdate ◽  
Soluble Phosphate ◽  
Blue Colour ◽  
Molybdenum Blue ◽  
Single Solution

It has been found that a reagent containing sulphuric acid, ammonium molybdate and ascorbic acid may be used as a single-solution reagent for the determination of phosphate in sea water. Development of the molybdenum-blue colour is complete in 24 h at room temperature and in 30 min at 60° C; the colour is stable for at least 3 days. Beer's law is obeyed closely up to at least 500 μg PO43−-P/1. The salt error is approximately 4% with sea water of chlorinity 19·3%. The interference due to either arsenate or silicate at their concentrations in sea water is negligible.

scholarly journals Determination of reducing and total sugars in West Indian cherry (malpighia punicifolia, L.) juice

1969 ◽  
Vol 37 (3) ◽  
pp. 199-205
Author(s):  
Rafael Santini, Jr.
Keyword(s):  
Ascorbic Acid ◽  
Room Temperature ◽  
Reducing Sugars ◽  
Sugar Content ◽  
West Indian ◽  
Total Sugars ◽  
Total Sugar Content ◽  
Significant Difference ◽  
Cherry Juice

(1) Ascorbic acid is the substance responsible for the discrepancies found in the determination of reducing sugars and total sugars by the Lane-Eynon method. By correcting for ascorbic acid using the factor (F) 0.686, the discrepancy is eliminated and the Lane-Eynon method can be used. (2) To determine the total sugar content of West Indian cherry juice corrected reducing sugars only need be assayed, because it was proved experimentally and statistically that there is no significant difference between corrected reducing and corrected total sugars. (3) The sugar content of West Indian cherry juices stored at room temperature and at 45°F. does not change appreciably after 1 year. (4) At 45°F. ascorbic acid is lost less readily than at room temperature, but temperature produces no significant difference in the true sugar content of the juice.

EFFECTS OF STORAGE CONDITIONS AND PRESENCE OF FRUITING BRACTS ON THE GERMINATION OF ATRIPLEX HALIMUS AND SALSOLA VERMICULATA

1997 ◽  
Vol 33 (2) ◽  
pp. 149-155 ◽  
Author(s):  
A. E. OSMAN ◽  
F. GHASSALI
Keyword(s):  
Seed Germination ◽  
Cold Storage ◽  
North Africa ◽  
Room Temperature ◽  
Storage Temperature ◽  
Seed Storage ◽  
Storage Conditions ◽  
Shrub Species ◽  
Atriplex Halimus ◽  
Different Temperatures

Two shrub species, Atriplex halimus L. and Salsola vermiculata L., are considered useful for rehabilitation of degraded rangelands in west Asia and north Africa. They can be established from direct seeding and are capable of self-sowing. In this study, seed storage at different temperatures and the influence of fruiting bracts on seed germination were examined for the two species during two seasons. Fruits (utricles) were stored at 20–22°C (room temperature), 0°C or −22°C. Germination tests were carried out after 33, 56, 90, 152, 272 and 397 d in storage in the first season and after 44, 76, 104, 170, 288 and 412 d in the second season. Seeds were germinated in their fruiting bracts or after bract removal. Bract removal significantly improved seed germination of both shrubs regardless of storage temperature. For S. vermiculata the increase in germination was in the range of 1.3- to 14.7-fold compared with values for the intact fruit in Season 1 and 0.5 to 3.8 in Season 2. Similarly the ranges for A. halimus were 0.5- to 4.2-fold and 0.7- to 5.3-fold in the two seasons respectively. The effect of cold storage was greater on Salsola than on Atriplex. The reduction of the storage temperature from 21°C to 0°C and −22°C increased the longevity of S. vermiculata seeds by 2.8–46.6 times in Season 1 and by 2.9–2.6 times in Season 2. There was little or no effect on the longevity of A. halimus. A leachate prepared by soaking fruiting bracts from S. vermiculata significantly depressed germination (p < 0.01), the effect being greater on Salsola seeds (20% reduction) than on Atriplex seeds (8% reduction). A leachate from A. halimus produced a slight but non-significant reduction in germination.

scholarly journals The effect of selected substances on the stability of standard solutions in voltammetric analysis of ascorbic acid in fruit juices

2019 ◽  
Vol 17 (1) ◽  
pp. 655-662
Author(s):  
Radosław Kowalski ◽  
Artur Mazurek ◽  
Urszula Pankiewicz ◽  
Marzena Włodarczyk-Stasiak ◽  
Monika Sujka ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Room Temperature ◽  
Nutritive Value ◽  
Fruit Juices ◽  
Optimum Concentration ◽  
Voltammetric Analysis ◽  
The Stability ◽  
Standard Solutions

AbstractThe objective of the study was to identify suitable additives stabilizing standard solutions of ascorbic acid (AA) that would not cause interference in the analytical process with the use of voltammetry in the determination of the AA content in food products. In addition, the effect of various conditions of storage of selected fruit juices and drinks on the concentration of vitamin C was studied. The study demonstrated that AA degradation was inhibited the most effectively by tartaric acid and its optimum concentration was set to 200 mg L-1. Analysis of selected fruit juices stored in various temperature conditions confirmed that an elevation of temperature and extension of the time of storage caused a decrease in the content of vitamin C in the analyzed samples, while closing the packages caused a limitation of the changes in concentration of this vitamin. On the basis of literature data and of the results obtained in the present study it can be concluded that fruit juices should be stored at a temperature lower than room temperature to retain their nutritive value.

scholarly journals Cu-based metal–organic framework HKUST-1 as effective catalyst for highly sensitive determination of ascorbic acid

RSC Advances ◽  
2020 ◽  
Vol 10 (39) ◽  
pp. 22881-22890 ◽  
Author(s):  
Tianyang Shen ◽  
Tianchen Liu ◽  
Hanqi Mo ◽  
Zichen Yuan ◽  
Feng Cui ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Room Temperature ◽  
Metal Organic Framework ◽  
Solvent Method ◽  
Effective Catalyst ◽  
Highly Sensitive ◽  
Metal Organic ◽  
Sensitive Determination ◽  
Organic Framework

In this work, a Cu-based nanosheet metal–organic framework (MOF), HKUST-1, was synthesised using a solvent method at room temperature and it demonstrated high capability and sensitivity towards the oxidation of ascorbic acid (AA).

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