Application of the phenol-sulfuric acid method for the determination of glycogen in skeletal muscles and liver of rats

The possibility of using the phenol-sulfuric acid method for the determination of total glycogen, its acid-soluble and acid-insoluble fractions in the liver and skeletal muscles of rats was studied. It was found that the use of a precipitant in the isolation of total glycogen and its fractions increases the yield of the investigated substances. Key words: phenol-sulfate method, rats, liver, muscles, total glycogen, acid-soluble glycogen, acid-insoluble glycogen.

Quantification of total sugars and reducing sugars of dragon fruit-derived sugar-samples by UV-Vis spectrophotometric method

In the present work, the phenol-sulfuric acid method and the 3,5-dinitrosalicylic acid (DNS) method were developed with the aim to quantitatively analyze total sugars and reducing sugars, respectively. In regard with the phenol-sulfuric acid assay, 1.0 mL of sample was treated with 1.0 mL of 5% phenol, 5.0 mL of concentrated H2SO4 and measured at 485 nm, with the linearity range of 10–100 ppm for total sugars. The DNS method was performed on 2.0 mL of sample, using 1.5 mL of DNS at 80 °C for 10 minutes and measured at 510 nm, with the linearity range of 50–400 ppm for reducing sugars. The sugar contents of white dragon fruit-derived sugar-samples (extracted from species in Binh Thuan province, Vietnam) were also estimated by the above measured methods, exhibiting the total sugars of above 90% and the reducing sugars of above 5%. The methods were well-performed with the acceptable relative standard deviations of repeatability in accordance with the Association of Official Analytical Chemists (AOAC).

Optimization of Solid-State Fermentation Conditions of Astragali Radix Residues and Changes of Its Nine Constituents Content Before and After Fermentation

Background: For the last few years huge quantity of herb residues are discharged in China, and so far there is not a good solution. The current methods of disposal and utilization of herb residues (stacking, incineration, and landfill) were not only great harmful to the ecological environment, but also cause the waste of medicinal herb resources. The fermentation can further decompose and transform the active ingredients and nutrients in herb residue, so the fermentation technology has good application prospect in the treatment of herb residues. In this study, we investigated the applicability of fermentation processes with the Aspergillus niger (ACCC 30583) strain for the reuse of Astragali Radix residues (ARR) by comparing the content changes of its nine constituents before and after fermentation. The contents of total protein and crude fat in the ARR were determined via near-infrared scanning; the iron, copper, zinc, and manganese contents were assayed with atomic absorption spectroscopy, the calycosin-7-glucoside and astragaloside Ⅳ content were determined by HPLC, and the polysaccharide content was determined via phenol sulfuric acid spectrophotometry. Results: The optimum fermentation conditions for ARR with ACCC 30583 was culture medium content 60%, fermentation time 5 days, and fermentation temperature 28 ℃. Compared with the residues before fermentation, the contents of total protein, calycosin-7-glucoside, astragaloside Ⅳ, Astragali Radix polysaccharides (ARP), and manganese increased significantly, the iron content decreased significantly, and the crude fat, zinc, and copper contents exhibited no significant changes. Conclusions: The solid fermentation of ARR with the Aspergillus niger (ACCC 30583) strain effectively promoted the separation of astragaloside Ⅳ and ARP from ARR, which provided methodological basis for the effective reuse of herb residues.

Enhancing sensitivity of phenol-sulfuric acid assay using orthophosphoric acid as modifier

<p class="abstract"><strong>Background:</strong> Phenol-sulfuric acid assay has been widely used for quantification of sugars in biological fluid and industry. The conventional method originally proposed by Dubois et al, was modified several times for enhancing sensitivity of assay such as substituting phenol with other chromogens, by optimizing assay conditions and by adding phenol after dehydration reaction. Both conventional and modified assays have utilized acid catalysis property of sulphuric acid but effect of adding phosphoric acid has not been studied before.</p><p class="abstract"><strong>Methods:</strong> The present study was conducted in Department of Biochemistry, ANIIMS, Port Blair and IGIMS, Patna. The method being developed in our study consisted of adding orthophosphoric acid to the reaction mixture before addition of sulphuric acid. The method was optimized with different amounts of orthophosphoric acid. Statistical analysis was done using SPSS and Microsoft Excel software. </p><p class="abstract"><strong>Results:</strong> The current study found an enhancing effect (on sensitivity) of orthophosphoric acid in optimal concentration of 5.16 mmoles. Comparison among standard curves of methods that were compared showed that the curve was steepest for current study and average absorbance was 0.199±0.017 for conventional, 0.253±0.011 for method by Rasouli et al, and 0.290±0.013 for current study. Pooled serum analysis exhibited absorbance of 0.157±0.015 in conventional method while in modified conventional method absorbance was 0.234±0.010 and highest absorbance was observed in current study at 0.281±0.012.</p><p class="abstract"><strong>Conclusions:</strong> Our results suggest that orthophosphoric acid exerts a positively modifying effect on phenol sulphuric acid assay.</p><p class="abstract"> </p>

Hydrolysis of microcrystalline cellulose isolated from waste seeds of Leucaena leucocephala for glucose production

The waste seeds of Leucaena leucocephala (LLS) used in this study were unused residues obtained after oil and polysaccharides extraction. The microcrystalline cellulose (MCC) was isolated from LLS by acid treatment. MCC produced was, then, further converted to glucose by using sulphuric acid at 121 °C by varying the acid concentration and reaction time. The sugar composition was analyzed by using the phenol-sulfuric acid method and pre-column derivatization HPLC technique. The yield of glucose ranging from 70–85% could be obtained from MCC hydrolyzates, depending on the hydrolysis factors, which corresponding to around 57-75% of the percentage conversion of MCC to glucose.Cellulose isolated from LLS was, therefore, potentially suitable to be utilized in liquid biofuels and other value-added chemicals such as bioethanol, 5-hydroxymethylfurfural(HMF), and levulinic acid.

Selection of lactic acid bacteria for exopolysaccharide production

An important source of natural alternative to commercial additives that are commonly extracted from plants and animals is the exopolysaccharide (EPS) produced by lactic acid bacteria (LAB). A screening for EPS production by Lactobacillus delbrueckii, Lactobacillus rhamnosus NBRC 3425 and Weisella paramesenteroides was conducted to identify which among these three LAB would produce the highest yield of EPS. The test organisms were grown in a Semi-defined Medium (SDM) of Sanchez et al (2006) with some modifications. EPS production was confirmed by the formation of precipitate after mixing the broth medium with 95% absolute ethanol. Results of total sugar analysis by phenol-sulfuric acid assay revealed that estimated EPS yield of L. rhamnosus NBRC 3425 was significantly higher at p<0.05 than those of W. paramesenteroides and L. delbrueckii ssp. lactis with values of 0.1355g/L, 0.0652g/L and 0.0544g/L, respectively even though their viable count did not differ significantly from each other. Correspondingly, the pH of L. rhamnosus NBRC 3425 media was also significantly higher (pH 4.03) than L. delbrueckii (pH 3.60) and W. paramesenteroides (pH 3.83).