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.

scholarly journals KAJIAN KARAKTERISTIK OBJEKTIF DAN SUBJEKTIF TUAK AREN (Arenga pinnata) BERDASARKAN LAMA WAKTU PENYIMPANAN

2017 ◽  
Vol 5 (1) ◽  
Author(s):  
Dhyana Putri
Keyword(s):  
Room Temperature ◽  
Storage Time ◽  
Fermentation Process ◽  
Test Method ◽  
Acceptance Test ◽  
Total Acid ◽  
Titration Method ◽  
Organoleptic Test ◽  
Palm Juice

Palm tuak is one of the traditional drink that is usually consumed by majority people in Bali. Tuak palm is produced from fermented palm juice. The fermentation process makes sucrose contained in palm juice will turn into alcohol and continues to acetic acid. The aim of this research is to know the characteristic objective and subjective palm tuak (Arenga pinnata) based on the storage time. The method in this research was quasi experiment design. The samples of palm tuak were stored at room temperature (24-30°C) on the first day to fifth day. This research was conducted by measuring characteristics objective and subjective at palm tuak, determination of ethanol's concentration by gas chromatography (GC), determination of the pH by pH stick, determination of total acid by titration method, and organoleptic test by acceptance test method. The results showed that the ethanol content obtained during time storage of first to fifth day are 8,1512%, 8,234%, 9,117%, 10,6214%, dan 11,615% respectively. The pH was determined is 4. While total acid obtained during time storage of first to fifth day are 0,321%, 0,421%, 0,433%, 0,472%, dan 0,480%. The result of organoleptic test palm tuak showed that palm tuak that were stored on the first day are the most preferred among the others in terms of taste, color, and aroma.

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.

Colorimetric Method for the Determination of Ethylene Dibromide Residues in Grains and Air

1976 ◽  
Vol 59 (6) ◽  
pp. 1262-1265
Author(s):  
Jois R Rangaswamy ◽  
Yadathora N Vijayashankar ◽  
Mysore Muthu
Keyword(s):  
Colorimetric Method ◽  
Oxidizing Agent ◽  
Ethylene Dibromide ◽  
Air Sample ◽  
The Relationship ◽  
Bromo Compound

Abstract A method based on the hydrolytic debromination of ethylene dibromide (EDB) in the presence of an oxidizing agent has been developed. Bromine liberated from inorganic bromide is used to brominate p-rosaniline. The intensity of the resulting violet-red bromo compound in chloroform is measured at 580 nm. The relationship between absorbance and concentration of EDB is linear in the range of 5–60 μg. The method is very sensitive and as little as 0.50 ppm unchanged EDB residue in a 20 g sample of fumigated grain and 1 ppm EDB in a 10 ml air sample can be detected.

Headspace Sampling and Gas Chromatographic Determination of Styrene Migration from Food-Contact Polystyrene Cups into Beverages and Food Simulants

1981 ◽  
Vol 64 (5) ◽  
pp. 1122-1130 ◽  
Author(s):  
Sandra L Varner ◽  
Charles V Breder
Keyword(s):  
Gas Chromatography ◽  
Room Temperature ◽  
Detection Limits ◽  
Chromatographic Determination ◽  
Headspace Sampling ◽  
Ionization Detector ◽  
Migration Studies ◽  
Flame Ionization ◽  
And Storage

Abstract Migration studies using coffee, tea, water, and 8% ethanol were conducted with various types of foodcontact polystyrene cups. Study conditions simulated filling and storage at room temperature and hot-filling or pasteurization above 150°F (65.6°C). The quantity of styrene migrating was determined by headspace sampling and gas chromatography (GC). The GC column was 6% Carbowax 20M on Chromosorb 101 with quantitation via a flame ionization detector. Detection limits ranged from 3 to 10 ppb in various liquids. The method and results of the migration studies are presented.

Preliminary Studies on Weathering of Chlordane Residues

1965 ◽  
Vol 48 (5) ◽  
pp. 952-954
Author(s):  
Alfred D Thruston
Keyword(s):  
Gas Chromatography ◽  
Quantitative Determination ◽  
Plant Extracts ◽  
Room Temperature ◽  
Agricultural Products ◽  
Qualitative And Quantitative ◽  
Chromatographic Peaks ◽  
The Many ◽  
Ppm Level

Abstract The qualitative and quantitative determination of chlordane residues on raw agricultural products has been best achieved by gas chromatography techniques. While good recoveries (90–100% at the 0.1 ppm level) have been obtained from plant extracts with added standard chlordane, weathered chlordane residues show changes in number and size of gas chromatographic peaks. Chlordane at the 50 µg level, when exposed to the air at room temperature over a period of time, showed progressive decomposition and loss of the many components that make up chlordane.

scholarly journals Chlorophyll as an indicator of green tea quality

2014 ◽  
Vol 83 (10) ◽  
pp. S103-S109 ◽  
Author(s):  
Martina Ošťádalová ◽  
Bohuslava Tremlová ◽  
Jana Pokorná ◽  
Martin Král
Keyword(s):  
Chlorophyll Content ◽  
Green Tea ◽  
Storage Time ◽  
Chlorophyll Concentration ◽  
Storage Period ◽  
Storage Conditions ◽  
Qualitative Variable ◽  
Chlorophyll Contents ◽  
Tea Quality ◽  
The Relationship

The objective of this work was to study the changes in chlorophyll contents in green teas stored under different conditions and to suggest the most suitable way and length of green tea storage. A secondary aim was to evaluate the possibility of using the chlorophyll content as an indicator of tea freshness. Samples for analysis were obtained from a range of tea-growing regions. Chlorophyll contents were measured using UV-vis spectrophotometry. Chlorophyll absorbance was measured at 642.5 and 660 nm. Prior to storage, chlorophyll concentration in teas ranged from 1.12 to 1.89 mg per 1 g of tea, which corresponded to data given by other authors. Storage was found to lead to a decline in chlorophyll concentration. From the 6th month of storage onwards, a significant decrease (P < 0.05) was observed in all samples, irrespective of storage conditions. Based on the findings of this study, original and metal packaging can be considered the most chlorophyll-friendly. On the other hand, glass and paper packaging stored in direct daylight were found to have the strongest impact on chlorophyll concentration. Overall, it can be concluded that the storage time can have a strong influence on oolong green tea colour as an important qualitative variable. Thus, the shelf-life of tea should be shorter than the 12 months claimed by most manufacturers. Once the relationship between changes in chlorophyll concentration and length of the storage period had been established, the chlorophyll content was suggested as an indicator of the storage time (freshness) of a tea substance.

scholarly journals Influence of storage time and temperature on the activity of urease

2019 ◽  
Vol 51 (2) ◽  
pp. 159-163
Author(s):  
B. Alev ◽  
S. Tunali ◽  
R. Yanardag ◽  
A. Yarat
Keyword(s):  
Room Temperature ◽  
Storage Time ◽  
Urease Activity ◽  
Storage Temperature ◽  
Practical Importance ◽  
Storage Conditions ◽  
Relative Activity ◽  
Significant Loss ◽  
Long Term Storage ◽  
Activity Measurements

Enzymes are made of protein, that is why they are sensitive molecules and are affected by storage conditions. A small change in enzyme activity during storage may cause a big error in analysis results. The aim of the study was to evaluate the effects of storage time and temperature on urease activity. Urease solutions were prepared at different activities (from 100 to 2000 U/mL) and stored at room temperature, in the refrigerator (4°C), and in the deep freezer (-18°C and -80°C). Activity measurements were made at regular intervals until 28 days by the modified Weatherburn method. The relative activities of 100-1000 U/mL urease solutions stored at room temperature, 4, -18 or -80°C were 75% and below after 4 days. Twenty-eight days later, for 2000 U/mL urease solutions, only at room temperature, the relative activity was reduced to 37%, while at 4, -18 or -80°C, the relative activities were above 80%. Since urease can be maintained at 4°C for 28 days without significant loss of activity, it has practical importance. Low-activity urease solutions (such as 100-1000 U/mL) should not be stored at -18 or -80°C for short or long term storage, they should be stored at 4°C only for one day. Keywords: Urease activity, storage time, storage temperature

scholarly journals Chemical Variability in the Composition of Zhumeria majdae (Rech. F. & Wendelbo) Essential Oil According to Storage Time and Temperature

Horticulturae ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 463
Author(s):  
Akbar Karami ◽  
Fatemeh Tashani ◽  
Aminallah Tahmasebi ◽  
Filippo Maggi
Keyword(s):  
Essential Oil ◽  
Room Temperature ◽  
Storage Time ◽  
Storage Conditions ◽  
Gas Chromatography Mass Spectrometry ◽  
Average Value ◽  
Oil Storage ◽  
Chemical Variability ◽  
Refrigerator Temperature ◽  
Storage Temperatures

Zhumeria majdae (Rech. F. & Wendelbo) is an aromatic herb belonging to the Lamiaceae family, traditionally employed in the Persian medicine for the treatment of a wide number of diseases. In the present study, the chemical composition of Z. majdae essential oil obtained from the plant’s aerial features, and stored at various temperatures (refrigerator temperature 4 °C, freezer temperature −20 °C, and room temperature 20 ± 3 °C) and times (0, 3, 6, and 9 months) was studied. The essential oil was isolated through hydrodistillation, and its composition was evaluated by gas chromatography/mass spectrometry (GC/MS). The results showed that the composition of essential oils changed as a function of the various storage temperatures and times. Linalool (34.85–48.45%), camphor (27.09–39.17%), limonene (1.97–4.88%), and camphene (1.6–4.84%) made up the main volatile compounds which showed differences in their concentrations according to the various storage conditions. Notably, when compared to a non-stored treatment sample (analyzed immediately after essential oil collection), the amount of linalool and camphor increased in all samples stored in all conditions of temperature and time, with the exception of the samples stored for nine months at room temperature. On the other hand, limonene and camphene contents decreased during the storage treatments, showing that the highest content of these compounds occurred in the non-stored treatment. Essential oil storage at the freezer temperature and for three months storage time resulted in the highest average value of the major constituents, highlighting these as the best conditions for obtaining the highest content of the major compounds.

Effects of Flavorings, Storage Conditions, and Storage Time on Survival of Staphylococcus aureus in Sürk Cheese

2005 ◽  
Vol 68 (7) ◽  
pp. 1487-1491 ◽  
Author(s):  
TUĞRUL M. MASATCIOĞLU ◽  
YAHYA K. AVŞAR
Keyword(s):  
Staphylococcus Aureus ◽  
Room Temperature ◽  
Storage Time ◽  
Storage Conditions ◽  
Black Pepper ◽  
Ash Content ◽  
Mold Growth ◽  
Storage Duration ◽  
And Storage ◽  
Over Time

The objectives of this study were to determine the cumulative effects of flavorings (chili pepper, thyme, mint, cumin, nutmeg, allspice, clove, cinnamon, black pepper, salt, and hot red pepper paste), storage conditions, and storage time on the survival of Staphylococcus aureus in Sürk cheese and to monitor the associated chemical changes. Sürk cheese, a traditional Turkish cheese, was produced by heating diluted nonfat yogurt and adding flavorings to the resultant acid-heat curd. The cheese was later inoculated with S. aureus, shaped conically, and stored aerobically for mold growth and anaerobically in olive oil for 30 days at room temperature. The moisture content of aerobically stored cheese decreased over time and led to increases in total solids, salt, salt-in-moisture, and ash content during ripening (P &lt; 0.05). The presence or absence of the flavorings had no significant effect, whereas storage conditions and storage duration decreased the survival of S. aureus (P &lt; 0.05).

Lewis-Base Adducts of Group 11 Metal(I) Compounds. LXVII Synthesis, Spectroscopy and Structural Systematics of Some 1 : 3 Adducts of Silver(I) Compounds with Triphenylarsine, [(Ph3As)3AgX], X = Cl, Br, I, SCN

1997 ◽  
Vol 50 (6) ◽  
pp. 577 ◽  
Author(s):  
Graham A. Bowmaker ◽  
Effendy ◽  
John D. Kildea ◽  
Allan H. White
Keyword(s):  
Room Temperature ◽  
Far Infrared ◽  
Phosphine Ligands ◽  
Lewis Base ◽  
X Ray ◽  
Bonding Parameters ◽  
Pseudo Halides ◽  
The Relationship ◽  
Far Infrared Spectra

The syntheses and room-temperature single-crystal X-ray structure determination of 1 : 3 adducts formed between silver(I) (pseudo-)halides, AgX, and triphenylarsine, AsPh3, are described (X = Cl, Br, I, SCN), [(Ph3As)3AgX], (1)–(4). The chloride (1) has been previously described as its acetone hemisolvate; other solvates (1a–d) (0·75 MeCN, MeOH, 1·5 pyridine, 0·75 2,6-dimethylpyridine) are isomorphous, being triclinic, P-1, a ≈ 13·5, b ≈ 14·0, c ≈ 14·25 Å, α ≈ 83, β ≈ 87, γ ≈ 76°, V ≈ 2600 Å3, Z = 2 f.u. The bromide (2), iodide (3) and thiocyanate (4) are isomorphous with [(Ph3P)3AgI], monoclinic, P21/n, a ≈ 19·1, b ≈ 14·0, c ≈ 17·7 Å, β ≈ 97°, Z = 4 f.u. In the chlorides, Ag–Cl are 2·494(5)–2·525(6) Å, with appreciably different Cl–Ag–As ranges (99·7(1)–114·3(1)° in the acetonitrile solvate; 104·8(2)–110·2(1)° in the 2,6-dimethylpyridine solvate) and more compact As–Ag–As distributions (overall range: 109·93(8)–113·26(3)°). For the bromide and iodide, Ag–X are 2·627(1) and 2·779(1) Å respectively, while for the thiocyanate Ag–S is 2·550(5) Å with Ag–S–C 104·2(3)°; the latter complexes also display wide ranges for many of the associated bonding parameters about the silver atom. The far-infrared spectra of [(Ph3As)3AgX] (X = Cl, Br, I) show v(AgX) bands at 217, 145 and 124 cm-1 respectively. The relationship between the v(AgX) wavenumbers and the Ag–X bond length r (AgX) is found to be the same as that for a range of AgX complexes with phosphine ligands, and is similar to that observed previously for analogous CuX complexes.

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