scholarly journals Development of an analytical method for determination of carbohydrates in food by gc - fid using chemical derivatization with anhydride acetic acid

2020 ◽  
Vol 4 (2) ◽  
pp. First
Author(s):  
Mạnh Khắc Nguyễn ◽  
Hòa Từ Nguyễn ◽  
Khuê Ngọc Nguyễn ◽  
Diễm My Lâm Huỳnh ◽  
Du Huy Nguyễn ◽  
...  
Keyword(s):  
Raw Milk ◽  
Carbohydrate Content ◽  
Honey Sample ◽  
Total Carbohydrate ◽  
Glucose Content ◽  
Fresh Milk ◽  
Oxime Formation ◽  
Relative Standard ◽  
Total Carbohydrates

The present research describes a simple and inexpensive derivatization method that uses acetylation to address the challenges associated with the quantification of the ten most common carbohydrates. The derivatization reaction has two periods : (1) The oxime formation of carbohydrates was carried out at 15 minutes, 500 µL of NH2OH 2.5%  and  60 ºC and (2) acetylation of carbohydrates was carried out at 45 minutes, 600 µL of AAA  and  80ºC. Most of the carbohydrates generate single peaks via chromatographic separation, except fructose, which generates a double peak. The procedure was successfully applied to analyze carbohydrates in some samples including honey, fresh milk, and polysaccharide hydrolyzate. The method validation results had the linear concentration range of carbohydrates at 50-4000 mg/g, the LODs at 20-50 µg/g, the relative standard deviations (% RSDs) of peak area under 5.0 % and the accuracy at 95–115% of recoveries. The method was applied to determine carbohydrate content in raw milk, honey, and hydrolysis polysaccharide extract. The results showed that the honey sample has fructose and glucose content of 65.8% and 33.4%, respectively, while sucrose makes up 0.74% of the total carbohydrate content. The raw milk sample has lactose content of 47.6% of the total carbohydrates. Some rare polysaccharides such as arabinose and xylose were found in the hydrolysis polysaccharide extract from the mushroom sample.  

scholarly journals Indirect and Direct Determination of the Casein Content of Milk by Kjeldahl Nitrogen Analysis: Collaborative Study

1998 ◽  
Vol 81 (4) ◽  
pp. 763-774 ◽  
Author(s):  
Joanna M Lynch ◽  
David M Barbano ◽  
J Richard Fleming
Keyword(s):  
Standard Deviation ◽  
Nitrogen Content ◽  
Relative Standard Deviation ◽  
Collaborative Study ◽  
Direct Determination ◽  
Raw Milk ◽  
Method Performance ◽  
Relative Standard ◽  
Milk Casein

Abstract The classic method for determination of milk casein is based on precipitation of casein at pH 4.6. Precipitated milk casein is removed by filtration and the nitrogen content of either the precipitate (direct casein method) or filtrate (noncasein nitrogen; NCN) is determined by Kjeldahl analysis. For the indirect casein method, milk total nitrogen (TN; Method 991.20) is also determined and casein is calculated as TN minus NCN. Ten laboratories tested 9 pairs of blind duplicate raw milk materials with a casein range of 2.42- 3.05℅ by both the direct and indirect casein methods. Statistical performance expressed in protein equivalents (nitrogen ⨯ 6.38) with invalid and outlier data removed was as follows: NCN method (wt%), mean = 0.762, sr = 0.010, SR = 0.016, repeatability relative standard deviation (RSDr) = 1.287℅, reproducibility relative standard deviation (RSDR) = 2.146%; indirect casein method (wt℅), mean = 2.585, repeatability = 0.015, reproducibility = 0.022, RSDr = 0.560℅, RSDR = 0.841; direct casein method (wt℅), mean = 2.575, sr = 0.015, sR = 0.025, RSDr = 0.597℅, RSDR = 0.988℅. Method performance was acceptable and comparable to similar Kjeldahl methods for determining nitrogen content of milk (Methods 991.20, 991.21,991.22, 991.23). The direct casein, indirect casein, and noncasein nitrogen methods have been adopted by AOAC INTERNATIONAL.

scholarly journals Determination of Four Fluoroquinolones in Milk by Liquid Chromatography

1997 ◽  
Vol 80 (5) ◽  
pp. 982-987 ◽  
Author(s):  
José E Roybal ◽  
Allen P Pfenning ◽  
Sherri B Turnipseed ◽  
Calvin C Walker ◽  
Jeffrey A Hurlbut
Keyword(s):  
Fluorescence Detection ◽  
Solid Phase ◽  
Raw Milk ◽  
Extraction Column ◽  
Isocratic Elution ◽  
Standard Curve ◽  
Milk Samples ◽  
Relative Standard ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method with fluorescence detection is presented for the analysis of 4 fluoroquinolones; enrofloxacin (ENRO), ciprofloxacin (CIPRO), sarafloxacin (SARA), and difloxacin (DIFLX) in milk. The procedure consists of extraction of milk with acidified ethanol, isolation and retention on a cation exchange solid-phase extraction column, elution with basic methanol, and LC analysis with fluorescence detection. LC analysis is performed by isocratic elution using an acetonitrile-2% acetic acid (15 + 85) mobile phase and an Inertsil phenyl column with fluorescence detection at excitation and emission wavelengths of 278 and 450 nm, respectively. A target level of 10 ppb for each of the 4 fluoroquinolones has been established for this method. Average recovery from fortified raw milk samples (5-100 ppb each) based on a 5-point standard curve calculation was 70-90%, with relative standard deviations of <15%.

The effect of growth temperature on dry weight and carbohydrate content of onion (Allium cepa L. cv. Creamgold) bulbs

1982 ◽  
Vol 33 (3) ◽  
pp. 559 ◽  
Author(s):  
BT Steer
Keyword(s):  
Allium Cepa ◽  
Growth Temperature ◽  
Dry Weight ◽  
Carbohydrate Content ◽  
Controlled Environment ◽  
Fresh Weight ◽  
Tissue Water ◽  
Total Carbohydrate ◽  
Glucose Content ◽  
Allium Cepa L

Onion bulbs (Allium cepa L. cv. Creamgold), grown in a phytotron from seed, had a dry weight as percentage of fresh weight that decreased as growth temperatures increased from 22/16 to 33/28�C day/night. There were no significant differences between growth temperatures in the fructose, sucrose or fructan content and, although glucose content was higher at high temperatures, there was no correlation of total carbohydrate content with growth temperature. The sum of fructose, glucose and sucrose per unit tissue water was constant between temperatures, suggesting that the mono- and disaccharide content may control the bulb water content. These results, from controlled-environment tests, predict that in the field the best yield of dry weight as a percentage of fresh weight will be obtained at low growth temperatures.

scholarly journals Measurement of macroalgae total carbohydrate content found in Lendang Luar coast, Lombok, Indonesia for potential sources of bioethanol

2021 ◽  
Vol 913 (1) ◽  
pp. 012077
Author(s):  
B T K Ilhami ◽  
A S Abidin ◽  
N W R Martyasari ◽  
N S H Kurniawan ◽  
H Padmi ◽  
...  
Keyword(s):  
Alternative Energy ◽  
Colorimetric Assay ◽  
Carbohydrate Content ◽  
Raw Material ◽  
Total Carbohydrate ◽  
High Carbohydrate ◽  
Total Carbohydrate Content ◽  
Potential Sources ◽  
Total Carbohydrates ◽  
Total Analysis

Abstract Bioethanol is a renewable alternative energy through the process of fermenting sugar from carbohydrate sources by adding microorganisms such as yeast or bacteria. Macroalgae or known as seaweed is one of the producers in the marine environment which has a high carbohydrate content so that it can be used as raw material for bioethanol. Macroalgae contains specific carbohydrates including laminarin, mannitol, alginate, agar and polysaccharides. The high carbohydrate content indicates the ethanol content produced. The aim of the study was to initial screen total carbohydrates in red algae (G. latifolium and G rugosa) and brown algae (M rosea, S. crassifolium, S. cristaefolium, S. polycystum, P.australis and T. muray ana). Carbohydrate total analysis was performed by colorimetric assay using the BioVision kit. The overall carbohydrate content found in macroalgae samples in this study was 28.23 fig (DW)1. The highest carbohydrate content was obtained by G. latifolium (37.50 fig (DW)1), followed by G rugosa (34.27 fig (DW)1) and S. cristaefolium (33.33 fig (DW)1). Current results show that macroalgae exhibits sufficient amounts of carbohydrate which could potentially be further developed as source for biotehanol.

Determination of Carbohydrates in Soluble Coffee by Anion-Exchange Chromatography with Pulsed Amperometric Detection: Interlaboratory Study

1995 ◽  
Vol 78 (3) ◽  
pp. 768-782 ◽  
Author(s):  
Jacques Prodolleet ◽  
Emmanuel Bugner ◽  
Max Feevberg
Keyword(s):  
Anion Exchange ◽  
Pure Water ◽  
Collaborative Study ◽  
Amperometric Detection ◽  
Exchange Chromatography ◽  
Anion Exchange Column ◽  
Relative Standard ◽  
Total Carbohydrates ◽  
Soluble Coffee

Abstract A collaborative study was conducted to validate a liquid chromatographic (LC) method to determine the free and total (after acid hydrolysis) carbohydrate profile of soluble coffee. Carbohydrates were separated on a pellicular anion-exchange column using pure water as mobile phase, and were detected by pulsed amperometry. Eleven collaborators were sent 6 test samples of commercial soluble coffee for duplicate analysis. They were also sent a practice sample with known levels of free and total carbohydrates and material for preparation of all standard solutions. The reproducibility relative standard deviations (RSDR) were 9.9–59.5% for mannitol, 35.6–72.6% for fucose, 4.9–21.1% for arabinose, 4.1–13.0% for galactose, 6.1–24.3% for glucose, 10.0–41.6% for sucrose, 20.2–37.7% for xylose, 10.6–40.0% for mannose, 15.5–71.7% for fructose, and 17.8–97.9% for ribose. Precision in the determination of free and total carbohydrates was very similar. The average repeatability RSDr and RSDR values were 4.5 and 14.3%, respectively, for carbohydrate levels above 0.3%. The precision of the technique was considered good, regardless of the usual peak integration problems always encountered in LC, the low levels of free carbohydrates, the hydrolysis step, and the relative lack of experience of most participating laboratories. The method allows good and reproducible separation of all major carbohydrates found in soluble coffee and is, therefore, suitable for routine analysis.

scholarly journals Influence of Carbohydrate Additives on the Growth Rate of Microalgae Biomass with an Increased Carbohydrate Content

Marine Drugs ◽  
2021 ◽  
Vol 19 (7) ◽  
pp. 381
Author(s):  
Anna Andreeva ◽  
Ekaterina Budenkova ◽  
Olga Babich ◽  
Stanislav Sukhikh ◽  
Vyacheslav Dolganyuk ◽  
...  
Keyword(s):  
Growth Rate ◽  
Chlorella Vulgaris ◽  
Nutrient Medium ◽  
Dunaliella Salina ◽  
Arthrospira Platensis ◽  
Carbohydrate Content ◽  
Biofuel Production ◽  
Total Carbohydrate ◽  
Microalgae Biomass ◽  
Total Carbohydrates

Our study focused on investigating the possibilities of controlling the accumulation of carbohydrates in certain microalgae species (Arthrospira platensis Gomont, Chlorella vulgaris Beijer, and Dunaliella salina Teod) to determine their potential in biofuel production (biohydrogen). It was found that after the introduction of carbohydrates (0.05 g⋅L−1) into the nutrient medium, the growth rate of the microalgae biomass increased, and the accumulation of carbohydrates reached 41.1%, 47.9%, and 31.7% for Arthrospira platensis, Chlorella vulgaris, and Dunaliella salina, respectively. Chlorella vulgaris had the highest total carbohydrate content (a mixture of glucose, fructose, sucrose, and maltose, 16.97%) among the studied microalgae, while for Arthrospira platensis and Dunaliella salina, the accumulation of total carbohydrates was 9.59% and 8.68%, respectively. Thus, the introduction of carbohydrates into the nutrient medium can stimulate their accumulation in the microalgae biomass, an application of biofuel production (biohydrogen).

scholarly journals Effects of carbohydrate content in seeds on the germination and viability after cryopreservation

2021 ◽  
Vol 101 (1) ◽  
pp. 6-13
Author(s):  
Laura Arystan ◽  
◽  
Tolkyn Kamsayeva ◽  
Saltanat Tleukenova ◽  
Denis Sirman ◽  
...  
Keyword(s):  
Seed Quality ◽  
Germination Rate ◽  
Carbohydrate Content ◽  
Time Interval ◽  
Total Carbohydrate ◽  
Time Intervals ◽  
Total Carbohydrate Content ◽  
Pearson Coefficient ◽  
Stage 4 ◽  
Total Carbohydrates

This article is devoted to the study of the influence of cryopreservation on the preservation of sowing qualities of seeds of representatives of the genus Picea: P. asperata (Rough spruce) and P. pungens (Spiny spruce). As an alternative shock method of cryopreservation, the method of step-by-step 3-step temperature reduction was used 1 stage +4 °C, 2 stage –18 °C, 3 stage –196 °C liquid nitrogen. Additionally, the effect of 4 time intervals (1 hour, 24 hours, 72 hours and 168 hours) of step freezing on seed quality was investigated. To explain the results by photometry, the total carbohydrate content of the seeds is determined before the 3rd freezing step (cryo interaction). The analysis of the results of germination showed that the seeds of the studied species respond in different directions to the step cryo freezing. So, seeds of P. asperata germination in all tree experimental variants are higher on 4–32 % than in the control variant; and the maximum results are revealed in the variant with time intervals of 168 hours. For P. pungens seeds, the germination rates in experimental variants were on 18–22 % lower than in the control; and the largest germination rate of seeds among experimental variations are revealed in variant with interval 24 hours. The determination of the total carbohydrate content of the tested seeds at different cryogenic freezing intervals found that this indicator varied significantly depending on the time interval. The lowest values of total carbohydrates are found in variation with a time interval — 24 hours. The maximum total carbohydrate content is determined in a variation with a time interval — 1 hour. Correlation analysis between seed germination indices and total carbohydrate content established a high relationship between these indices. So, for P. asperata, the value of the Pearson coefficient was 0.86, and for P. pungens seeds — 0.91.

Liquid Chromatographic Method for Determination of Sulfamethazine Residues in Milk: Collaborative Study

1993 ◽  
Vol 76 (4) ◽  
pp. 725-729 ◽  
Author(s):  
John D Weber ◽  
Michael D Smedley ◽  
◽  
B Bradley ◽  
G Carignan ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Raw Milk ◽  
Similar Data ◽  
Outlier Test ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Repeatability And Reproducibility ◽  
Control Milk ◽  
Liquid Chromatographic

Abstract Seven laboratories participated in a collaborative study of a liquid chromatographic (LC) method for determination of sulfamethazine (SMZ) residues in raw milk that were previously frozen. The milk is extracted with chloroform, the chloroform is evaporated, and the residue is suspended in hexane and extracted with 0.1 M KH2P04 (PDP) solution. The PDP extract is analyzed by LC on a C18 column with methanol–0.1M PDP (30 + 70) as mobile phase. Individual laboratories were instructed to analyze 5 replicates each of control milk, fortified control milk at 2 levels, and 3 blind samples. Blind samples included raw milk fortified with SMZ at 10 and 20 ppb and 1 sample containing SMZ residue from a dosed cow. For blind fortified samples containing 10 ppb SMZ, average recovery and relative standard deviations for repeatability and reproducibility (RSDr and RSRR) based on the results from 6 of the 7 participating laboratories were 8.21 ppb, 7.16%, and 23.16%, respectively. Similar data, including results from a seventh participant who reported instrumental problems but was not eliminated by the Dixon outlier test, were 9.13 ppb, 8.38%, and 31.94%, respectively. These results demonstrate that the method is suitable for the determination of SMZ residues in milk at 10 ppb and above. The method was adopted first action by AOAC International.

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