scholarly journals Determination of Peroxide Value in Sunflower Halva using a Spectrophotometric Method

2010 ◽  
Vol 67 (2) ◽  
Author(s):  
Vlad MURESAN ◽  
Sevastita MUSTE ◽  
Emil RACOLTA ◽  
Cristina Anamaria SEMENIUC ◽  
Simona MAN ◽  
...  
Keyword(s):  
Peroxide Value ◽  
Room Temperature ◽  
Lipid Fraction ◽  
Ammonium Thiocyanate ◽  
Storage Conditions ◽  
Complexing Agent ◽  
Root Extract ◽  
Sunflower Seeds ◽  
The One

Sunflower halva, popular in countries from Eastern Europe, is made of sunflower tahini, cooked sugar and soapwort root extract. Lipid fraction in traditional sunflower halva is rich in polyunsaturated fatty acids, susceptible to peroxidation. Oxidation of the lipids is one of the main causes of lipid rich food deterioration leading to formation of off-flavour that negatively affect their quality and shelf life. In this study the initially phase of oxidation in sunflower halva was assessed, using as indicator the peroxide value (PV). The protocol followed was the one described by IDF standard which uses ammonium thiocyanate as Fe(III)-complexing agent. Halva samples stored at room temperature, in open air conditions for four months, respectively ten months were analyzed. The PV of sunflower halva at 10 months of storage was ~ 2 times higher that the PV of sunflower halva at 4 months of storage. The samples of sunflower seeds used for the analysis were freshly dehulled and dehulled and then stored at room temperature in open air conditions for four months. The freshly dehulled sunflower seeds had a PV of 4.14 meq O2/Kg fat, similar values with those reported in the literature. The sunflower seeds dehulled and than stored for 4 months at room temperature in open air conditions had a PV of 89.47 meq O2/Kg fat, rancid taste being detected. Regarding the oxidative stability of sunflower halva, care must be taken on storage conditions and packaging – temperature and oxygen availability. For further studies addition of supplementary antioxidants should be considered.

scholarly journals Stability of Hemocytometry Parameters Under Different Sample Storage Conditions

Medicina ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 54-74
Author(s):  
A. S. Shulga ◽  
◽  
N. N. Kraynova ◽  
D. V. Burtsev ◽  
◽  
...  
Keyword(s):  
Room Temperature ◽  
Clinical Laboratory ◽  
Hematological Parameters ◽  
Storage Conditions ◽  
The Other ◽  
Sample Collection ◽  
Hematological Indices ◽  
Temperature Regimes ◽  
Time Changes ◽  
The One

Sample stability is essential for reliable results in clinical laboratory practice. The aim of the work was to investigate the change in values of hematological indices in samples stored for up to 72 hours under different temperature regimes. A total of 60 whole blood samples stored under different conditions were analyzed: at room temperature (25°C), heated to 35°C and cooled to 4°C. Analysis was performed at different time points: immediately after blood sampling and then consecutively after 3, 6, 12, 24, 48 and 72 hours. K2EDTA anticoagulant tubes were used, and results were obtained using a UniCel DxH 800 hematology analyzer. The median shift of the parameters relative to baseline for each combination of time and temperature was assessed using the Wilcoxon matched pairs test. The shift in hemogram values obtained using Bland-Altman plots was compared with the maximum permissible error specified in the quality specification for the desirable error. Hemoglobin, erythrocyte count, mean erythrocyte hemoglobin content and platelet content were stable for at least 72 hours at all temperatures used in the experiment. For the other tested parameters, the first unacceptable changes in hemogram values were observed after 3 hours when the samples were stored at 25°C and 35°C. In samples cooled to 4°C, the first statistically significant differences were recorded after 6 hours. As a result, storage of samples for 72 hours at room temperature led to reliable unacceptable changes in 6 hemogram parameters of the 11 studied, at 4°C 5 parameters changed unacceptably, and at 35°C – 7 parameters. The obtained results, on the one hand, indicate that when analyzing the results of hematological tests is performed with a delay after sample collection, changes in hematological parameters should be considered; on the other hand, they provide information about the list of parameters subject to temperature-time changes, as well as about the intensity of these changes.

scholarly journals Physicochemical Characteristics and Oil Keeping Quality of Two Cultivars of Sunflower (Helianthus annuus) Seeds

2019 ◽  
pp. 1-10
Author(s):  
A. Kafi ◽  
S. Gheyasuddin ◽  
M. H. Rashid
Keyword(s):  
Crude Protein ◽  
Room Temperature ◽  
Physicochemical Characteristics ◽  
Storage Conditions ◽  
Sunflower Seeds ◽  
Peroxide Values ◽  
Keeping Quality ◽  
Edible Purpose ◽  
Iodine Values

The work was conducted on sunflower seeds of two cultivars namely ‘Kironi’ and ‘Hysun-46’. Proximate composition of the seeds, chemical characteristics and fatty acid composition of the oils, and its keeping quality at different storage conditions were studied. Moisture content of Kironi seeds was nearly twice than Hysun-46 (8.03 vs 4.46%). Crude fat in Hysun-46 seeds was somewhat higher than Kironi. Kironi had significantly higher crude protein whereas Hysun-46 contained significantly higher percent of starch than Kironi (7.05 vs 3.90%). Physical characteristics of oil such as viscosity, colour and transparency changed with time during storage; specific gravity and smoking temperature, however, remained unchanged. Acid values of the freshly extracted oil from Hysun-46 were unexpectedly high (98.75). Iodine values were found to be higher in Kironi than Hysun-46, so the former had greater proportion of unsaturation. Saponification values of the oils decreased with the time in open vessel, in amber coloured bottle at 4°C and also in boiled oil kept at room temperature. However, these values registered an increase in oils stored in closed vessel and amber coloured bottle at room temperature. Peroxide values increased in oils under all conditions except in amber bottle at 4°C. The ratio of linoleic acid to oleic acid in Kironi (2.3:1) was higher than that in Hysun-46 (1.9:1), indicating that Kironi had more semidrying capacity and suitable for edible purpose. The freshly extracted oil had attractive appearance. Between the two oil samples, Kironi seems somewhat superior to Hysun-46.

Lewis-Base Adducts of Group 11 Metal(I) Compounds. LXXIV Synthesis and Structure of the 1 : 1 Adduct of Silver(I) Nitrate with Triphenylstibine

1997 ◽  
Vol 50 (6) ◽  
pp. 671 ◽  
Author(s):  
Effendy ◽  
John D. Kildea ◽  
Allan H. White
Keyword(s):  
Single Crystal ◽  
Structure Determination ◽  
Related Species ◽  
Room Temperature ◽  
Structural Data ◽  
Lewis Base ◽  
One Dimensional ◽  
X Ray ◽  
The One

The synthesis and room-temperature single-crystal X-ray structure determination of the 1 : 1 adduct of silver(I) nitrate with triphenylstibine, AgNO3/SbPh3 (1 : 1), is recorded, being monoclinic, Cc,a 12·824(2), b 15·794(4),c 9·796(2) Å, β 117·50(1)°, Z= 4; conventional R on F was 0·030 for 2881 independent ‘observed’ (I > 3σ(I)) reflections. The complex is a one-dimensional polymer with bridging nitrate groups, resembling in this respect its phosphine and arsine analogues. The completion of this study, along with related species recorded in accompanying papers, means that full structural data are now available for the complete array AgNO3/EPh3 (1 : n), E = P, As, Sb, n = 1–4, with the one exception of E = Sb, n = 2.

Stability of Grape Seed Oil and its Antioxidant Tocotrienols

2014 ◽  
Vol 1030-1032 ◽  
pp. 370-373 ◽  
Author(s):  
Jaromír Lachman ◽  
Alena Hejtmánková ◽  
Zora Kotíková ◽  
Martin Dědina ◽  
Radomíra Střalková ◽  
...  
Keyword(s):  
Peroxide Value ◽  
Room Temperature ◽  
Seed Oil ◽  
Grape Seed ◽  
Storage Conditions ◽  
Oxidation Products ◽  
Light Conditions ◽  
Grape Seed Oil ◽  
The Stability ◽  
Primary Oxidation

For the experiment three different storage conditions were chosen: storage at room temperature of 22 °C in the light and in the dark and in the dark in a refrigerator at 4 °C. Parameters monitored were: peroxide value and changes in the content of α-, γ-and δ-tocotrienols and α - and γ-tocopherols during storage for 210 days (30 weeks). The peroxide value is an indicator of the content of primary oxidation products of oils. From analytical analyses results that the greatest destruction of grape oil occurs during storage at room temperature and access of light, where a peroxide value increased up to 484 meq. O2/kg oil). The least intrusive method of storage was in terms of temperature refrigerator (4 °C) in the dark, when during 30 days of storage peroxide value had risen only to 71.9 meq. O2/kg oil. Between these values ​​were values stored at room temperature in the dark (after 30 weeks storage 196 meq. O2/kg oil). From these parameters is clearly showed that to the stability of oil contribute significantly both factors - temperature and light conditions. The same trend was also found in tocotrienols. At room temperature and access of light was complete decomposition of α-tocotrienol in the 9th week of storage, γ-tocotrienol at 30 weeks of storage and δ-tocotrienol in the 18th week of storage. The most stable seems γ-tocotrienol > δ-tocotrienol > α-tocotrienol. When stored in the refrigerator in the dark, there was practically no decomposition of α-, γ-and δ-tocotrienols whose contents remained completely unchanged.

Determination of Ethylene Dibromide in Tropical Fresh Fruits Using Dean-Stark Apparatus and ECD-Gas Chromatography

1988 ◽  
Vol 51 (9) ◽  
pp. 727-730 ◽  
Author(s):  
YUMIKO NAKAMURA ◽  
YUKARI HASEGAWA ◽  
YASUHIDE TONOGAI ◽  
MINORU HANAFUSA ◽  
HIDEAKI HIROSE ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Room Temperature ◽  
Storage Time ◽  
Storage Conditions ◽  
Ethylene Dibromide ◽  
High Concentrations ◽  
Papaya Pulp ◽  
The Relationship

The concentration of residual EDB (ethylene dibromide) in tropical fresh fruits imported to Japan were investigated using the Dean-Stark apparatus and ECD-gas chromatography (ECD-GC) i.e. EDB was distilled into a small amount of n-hexane using a Dean-Stark apparatus and determined by ECD-GC. Recovery of EDB added to papaya pulp at the concentration of 0.1 ppm was more than 98.1% by the proposed method. The relationship between storage conditions and concentration of residual EDB was investigated for mango pulps; it was clarified that EDB content in mango pulps decreased with the storage time at room temperature (25°C) and refrigerated (7°C), but the content did not decrease for 6 d at −20°C. We surveyed the concentration of residual EDB in pulps, peels and seeds of the fresh fruits (grapefruits, papayas, mangos and litchis) imported to Japan in 1987 separately. Extremely high concentrations of EDB were found in the seeds of grapefruits. A similar trend was also observed in other fruits.

Radiochemical Purity, at Expiry, and Radiochemical Stability of Iodine-131 Labelled Meta-iodobenzylguanidine Concentrates for Intravenous Infusion

1996 ◽  
Vol 35 (04) ◽  
pp. 122-125 ◽  
Author(s):  
Cornelis Hoefnagel ◽  
Robert Maes ◽  
Jos Beijnen ◽  
Amon Wafelman
Keyword(s):  
Intravenous Infusion ◽  
Room Temperature ◽  
Solid Phase ◽  
Daily Practice ◽  
Storage Conditions ◽  
Dry Ice ◽  
131I Mibg ◽  
Practice Method ◽  
Iodine 131

Summary Aim: The determination of the amount of free [131I]iodide in [13lI]meta-iodobenzylguanidine (1131I]MIBG) concentrates for intravenous infusion under different storage conditions derived from daily practice. Method: The percentage of free [131I]iodide was determined in [131I]MIBG concentrates (1.6-3.9 GBq in 7.5 ml), kept on dry ice (up to expiry, 3 days after production) or, after thawing, at room temperature (up to 24 h). A validated solid phase extraction (SPE) assay was used. Results: Free [131 Niodide increased from 1.9% ± 0.34% at production to 4.4% ± 0.67% (mean ± SD; n = 5) at expiry in 3.7 GBq per 7.5 ml [131I]MIBG infusion concentrates, stored on dry ice (-78° C). At room temperature, formation of free [131 Niodide was found to be dependent on the radioactive concentration of the fluid. [131I]iodide levels increased from 3.1%, immediately after thawing, to 6.6% and 16.6% at t = 5 and 24 h, respectively, for a 3.9 GBq per 7.5 ml concentrate. Conclusion: The investigated formulation of [131I]MIBG concentrates, stored in its original packing containing dry ice, can generally be used up to expiry. After thawing, the undiluted concentrates should be administered to a patient within 3.5 h.

Interactions Between Al and Cr Thin Films

1976 ◽  
Vol 34 ◽  
pp. 638-639
Author(s):  
R. M. Anderson ◽  
T. M. Reith ◽  
M. J. Sullivan ◽  
E. K. Brandis
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Vacuum System ◽  
Processing Temperature ◽  
Diffusion Couples ◽  
Electronic Circuits ◽  
Intermetallic Formation ◽  
Si Substrates ◽  
Aluminum Silicon

Thin films of aluminum or aluminum-silicon can be used in conjunction with thin films of chromium in integrated electronic circuits. For some applications, these films exhibit undesirable reactions; in particular, intermetallic formation below 500 C must be inhibited or prevented. The Al films, being the principal current carriers in interconnective metal applications, are usually much thicker than the Cr; so one might expect Al-rich intermetallics to form when the processing temperature goes out of control. Unfortunately, the JCPDS and the literature do not contain enough data on the Al-rich phases CrAl7 and Cr2Al11, and the determination of these data was a secondary aim of this work.To define a matrix of Cr-Al diffusion couples, Cr-Al films were deposited with two sets of variables: Al or Al-Si, and broken vacuum or single pumpdown. All films were deposited on 2-1/4-inch thermally oxidized Si substrates. A 500-Å layer of Cr was deposited at 120 Å/min on substrates at room temperature, in a vacuum system that had been pumped to 2 x 10-6 Torr. Then, with or without vacuum break, a 1000-Å layer of Al or Al-Si was deposited at 35 Å/s, with the substrates still at room temperature.

STEM and ELS Observation of Early Oxide Formation on the Surface of Cr Thin Films

1980 ◽  
Vol 38 ◽  
pp. 412-413
Author(s):  
Fumio Watari ◽  
J. M. Cowley
Keyword(s):  
Thin Films ◽  
Optical System ◽  
Room Temperature ◽  
Oxide Formation ◽  
Initial Nucleation ◽  
Diffraction Patterns ◽  
Relationship Of ◽  
Multiple Twinning ◽  
Moderately High Temperature

STEM coupled with the optical system was used for the investigation of the early oxidation on the surface of Cr. Cr thin films (30 – 1000Å) were prepared by evaporation onto the polished or air-cleaved NaCl substrates at room temperature and 45°C in a vacuum of 10−6 Torr with an evaporation speed 0.3Å/sec. Rather thick specimens (200 – 1000Å) with various preferred orientations were used for the investigation of the oxidation at moderately high temperature (600 − 1100°C). Selected area diffraction patterns in these specimens are usually very much complicated by the existence of the different kinds of oxides and their multiple twinning. The determination of the epitaxial orientation relationship of the oxides formed on the Cr surface was made possible by intensive use of the optical system and microdiffraction techniques. Prior to the formation of the known rhombohedral Cr2O3, a thin spinel oxide, probably analogous to γ -Al203 or γ -Fe203, was formed. Fig. 1a shows the distinct epitaxial growth of the spinel (001) as well as the rhombohedral (125) on the well-oriented Cr(001) surface. In the case of the Cr specimen with the (001) preferred orientation (Fig. 1b), the rings explainable by spinel structure appeared as well as the well defined epitaxial spots of the spinel (001). The microdif fraction from 20A areas (Fig. 2a) clearly shows the same pattern as Fig. Ia with the weaker oxide spots among the more intense Cr spots, indicating that the thickness of the oxide is much less than that of Cr. The rhombohedral Cr2O3 was nucleated preferably at the Cr(011) sites provided by the polycrystalline nature of the present specimens with the relation Cr2O3 (001)//Cr(011), and by further oxidation it grew into full coverage of the rest of the Cr surface with the orientation determined by the initial nucleation.

Two-Stage Procedure for the Quantitative Determination of Autoprothrombin III Concentration and Some Applications

1967 ◽  
Vol 18 (01/02) ◽  
pp. 198-210 ◽  
Author(s):  
Ronald S Reno ◽  
Walter H Seegers
Keyword(s):  
Prothrombin Time ◽  
Factor Vii ◽  
Two Stage ◽  
Pronounced Increase ◽  
One Stage ◽  
Assay Procedure ◽  
Bovine Plasma ◽  
The One ◽  
Autoprothrombin C

SummaryA two-stage assay procedure was developed for the determination of the autoprothrombin C titre which can be developed from prothrombin or autoprothrombin III containing solutions. The proenzyme is activated by Russell’s viper venom and the autoprothrombin C activity that appears is measured by its ability to shorten the partial thromboplastin time of bovine plasma.Using the assay, the autoprothrombin C titre was determined in the plasma of several species, as well as the percentage of it remaining in the serum from blood clotted in glass test tubes. Much autoprothrombin III remains in human serum. With sufficient thromboplastin it was completely utilized. Plasma from selected patients with coagulation disorders was assayed and only Stuart plasma was abnormal. In so-called factor VII, IX, and P.T.A. deficiency the autoprothrombin C titre and thrombin titre that could be developed was normal. In one case (prethrombin irregularity) practically no thrombin titre developed but the amount of autoprothrombin C which generated was in the normal range.Dogs were treated with Dicumarol and the autoprothrombin C titre that could be developed from their plasmas decreased until only traces could be detected. This coincided with a lowering of the thrombin titre that could be developed and a prolongation of the one-stage prothrombin time. While the Dicumarol was acting, the dogs were given an infusion of purified bovine prothrombin and the levels of autoprothrombin C, thrombin and one-stage prothrombin time were followed for several hours. The tests became normal immediately after the infusion and then went back to preinfusion levels over a period of 24 hrs.In other dogs the effect of Dicumarol was reversed by giving vitamin K1 intravenously. The effect of the vitamin was noticed as early as 20 min after administration.In response to vitamin K the most pronounced increase was with that portion of the prothrombin molecule which yields thrombin. The proportion of that protein with respect to the precursor of autoprothrombin C increased during the first hour and then started to go down and after 3 hrs was equal to the proportion normally found in plasma.

Sign in / Sign up

Export Citation Format

Share Document