Investigating matrix interference in the pharmacopeial limit test for aluminum in citric acid: a re-examination, for revision of the method

In many pharmacopoeias, the limit test used for determining the level of aluminum in citric acid labeled for use in the manufacture of dialysate, is based on solvent extraction using 8-hydroxyquinoline and measurement of fluorescence. However, the fluorescence intensity (F.I.) readout from the extract of citric acid samples has been found to be highly dubious, showing low value, and even lower than that of a blank solution. The aim of this work therefore was to examine what effects the matrix has on the test. The comparison of the two standard curves of aluminum solutions in water, against those prepared in citric acid solutions revealed that they differed greatly in terms of slope and y-intercept. In addition, the F.I. values on the plot of the citric acid solution were much lower than that prepared in the water. In another experiment, a decrease in the F.I. of aluminum solution was clearly seen when the co-existing concentration of citric acid was increased. The results inferred that citric acid interfered with the test due to its acidity and metal-chelating capabilities. Based on this evidence, the pharmacopeial limit test for aluminum in citric acid should be revised; otherwise, it could yield results that underestimate aluminum levels and lead to inaccurate conclusions

The The Effect of Concentration of Citric Acid Solution on Extraction of Pectin from Watermelon Albedo

Watermelon albedo or the white flesh of watermelon rind contains pectin with high enough content. In this study was conducted the extraction of pectin from watermelon albedo by the liquid-solid extraction method. The citric acid solution was used as a solvent with concentrations varied by 4%, 7%, and 10%. The research steps include the pretreatment of raw material, the extraction, the posttreatment of extraction, and the analysis of pectin. The pretreatment aimed to reduce water content and reduce the size of raw material. The extraction process was the main process in which pectin dissolution occurred in the citric acid solvent. Furthermore, the posttreatment of extraction aimed to obtain pectin solid with the addition of ethanol. The final step was the analysis, including pectin yield, moisture content, methoxyl content, galacturonic acid content, and pectin functional group. Based on research obtained, an increase in the concentration of citric acid increased pectin yield, methoxyl content, and galacturonic acid content. The moisture content of pectin decreased with the increasing concentration of citric acid. Pectin yield, moisture content, methoxyl content, galacturonic acid content resulted from 10% concentration of citric acid solvent are 8.356%, 19.748%, 7.029%, and 69.048%, respectively. Based on FTIR analysis, the functional groups contained in pectin are hydroxyl group, methyl group, carbonyl group, and ether group. This functional groups are main constituents of pectin structure.

Citric Acid as an Alternative to Sulfuric Acid for the Hard-Anodizing of AA6061

Hard-anodized is a widely used method in the aeronautical sector to improve aluminum alloys abrasion and corrosion resistance. Aim of this work was to characterize the mechanical properties and resistance hard-anodized aluminum 6061 in citric acid solution as a replacement sulfuric acid solution were investigated. Aluminum alloy 6061 was used as the base material to produce the hard anodizing; this process was carried out in a citric and sulfuric acid solution, applying current densities 3 and 4.5 A/cm2 and subsequently exposed to 3.5 wt. % NaCl solution. Microstructure and mechanical properties of the anodizing material were characterized by scanning electron microscopy (SEM) and Vickers microhardness (HV). Corrosion behavior of the hard-anodized material it was carried out with electrochemical techniques as cyclic potentiodynamic polarization (CPP) and electrochemical impedance spectroscopy (EIS) respectively. Results obtained indicated that all samples anodized in citric acid solution showed negative hysteresis and lower corrosion current density (1 × 10−10 A/cm2), indicating generalized corrosion on the material surface. EIS results show that anodizing in citric acid solution and a current density of 4.5 A/dm2 provides better corrosion protection than a sulfuric acid solution.

PERSPECTIVE SEARCHES OF MEDICINAL PLANT RAW MATERIALS AS SOURCE OF POLYSACCHARIDES

The purpose of the conducted researches was studying of cones of a pine ordinary as source of polysaccharides in complex processing of raw materials. Cones of a pine ordinary were assembled during pollination. For the purpose of development of complex processing of raw materials researches on studying of the cones which remained after receiving pollen are conducted. Researches showed prospects of use of cones of a pine ordinary as source of polysaccharides after receiving pollen. The pectin content in ordinary pine cones, established by the oxalate method, was 1,2 ± 0,1%. Qualitative determination of pectin is proposed by colour reaction with solution of carbazole with alcohol 0,5%. Reaction with 10% lead (II) basic acetate was also used to identify pectin. One indicator of the detoxifying activity of pectin is the degree of esterification (ratio of esterified and free carboxyl groups). Low esterified pectins (esterification rate below 50%) are used as detoxicant. Important is the fact that the complex processing of ordinary pine cones will make it possible to obtain pectin actually from pollen production waste. In the developed scheme of complex processing of ordinary pine cones for hydrolysis-extraction of pectin-high substances from raw materials, it is proposed to use citric acid solution with pH 1,8-2,0. Methods for identifying and quantifying pectin in an object are valid. As a result of all the studies, a method was developed for producing pectin from ordinary pine cones in the complex processing of raw materials, the content of which was 1,2±0,1%, and the degree of esterification 13,20 ± 0,5%. The results of the conducted studies showed that the content of tannins in the studied raw materials of pine cones was 0,66±0,02%. As a result of all studies, a method of producing pectin from ordinary pine cones in complex processing of raw materials has been developed. The obtained results make it possible to recommend the obtained pectins as an effective detoxifying agent and a source of polysaccharides, tannins.

PHYSICOCHEMICAL, SENSORIAL AND MICROBIOLOGICAL ANALYSIS OF MINIMALLY PROCESSED FRUITS OF PAPAYA AND PINEAPPLE

The current study intended to discover the storage/shelf life of papaya and pineapple, minimally processed fruits, based on their physicochemical, sensorial, and microbiological analysis. They were stored at low temperature at 4?C for 8 days. Methods: The papaya slices were dipped into 1000ppm citric acid solution and a solution of 150ppm ascorbic acid and 1000ppm citric acid. On other hand, pineapple slices were dipped into a solution of 1% sodium chloride and 1% calcium chloride and another solution of 150ppm ascorbic acid and 1000ppm citric acid. Both fruit samples were immersed into the respective solutions for around 2-3minutes. Results: From the results of treatments, it was revealed that the combination of 150ppm ascorbic acid and 1000ppm citric acid solution, in both the samples showed the best outcomes. Conclusion: It ultimately concludes that after this treatment the minimally processed papaya and pineapple can be stored effectively and safely in good conditions for 8 days at low temperature.

Effect of Processing and Drying on Quality Evaluation of Ready-To-Cook Jackfruit

The study was conducted with the aim of processing and developing ready to cook jackfruit to evaluate their nutritional and sensory quality attributes. In this study, green tender jack fruits were harvested from 60 to 70 days after synthesis. Then the fruits were washed, peeled and cut into slices. The slices were treated by dipping into different solutions for each treatments viz. control (T1), 0.5% salt solution (T2), 0.2% citric acid solution (T3), 1000 ppm potassium metabisulfite (KMS) (T4), 1000 ppm KMS + 0.5% salt (T5), 1000 ppm KMS + 0.2% citric acid (T6), 0.5% salt + 0.2% citric acid (T7) and 1000 ppm KMS+ 0.2% citric acid+ 0.5% salt (T8). Then the treated sliced was steam blanched at 85°C temperature for 8 min. The roasted beef spices were mixed and then dried at 50°C, 60°C and 70°C temperature owing to preparation of ready to cook. Results revealed that ready to cook dried at 50°C, 60°C and 70°C temperature took 72 hrs, 48 hrs and 36 hrs respectively. Low potassium metabisulfite residue was observed with increasing blanching time and drying temperature. The physicochemical characteristics, phytochemical and antioxidant activities were retained more and the highest sensory score was obtained at 60°C temperature. The marketable life of the RTC jackfruit could be extended to more than 6 months. However, the findings suggest that green tender jackfruit treated with 1000 ppm KMS, blanched for 8 min and dried at 60°C is a quick and healthy option in terms of good marketable life, nutritional and sensory quality attributes. Keywords:Tender jackfruit, ready to cook, nutritional quality, sensory attributes, marketable life

Protective Effect of Solutions Containing Polymers Associated with Fluoride and Stannous Chloride on Hydroxyapatite Dissolution

This study investigated the protective effect of experimental solutions containing 4 polymers (polyoxirane, hydroxypropylmethylcellulose [HPMC], pectin, and an amino methacrylate copolymer [AMC]) in 2 concentrations (low and high) associated or not with sodium fluoride (F; 225 ppm F^–) or sodium fluoride plus stannous chloride (FS; 800 ppm Sn²⁺) on the dissolution of hydroxyapatite crystals (HA). Deionized water was the control. The pretreated HA was added to a 0.3% citric acid solution (pH 3.8). An automatic titrant machine added aliquots of 0.1 N HCl at a rate of 28 μL/min, in a total reaction time of 5 min. Groups were compared with 2-way ANOVA and Tukey’s test, and concentrations with Student <i>t</i> test (5%). The zeta potential of the HA treated with the solutions was measured. Significant differences were found for both factors and interaction (<i>p</i> &#x3c; 0.0001). The treatments with F and FS solutions resulted in a lower amount of dissolved HA than the control. Among the polymers’ solutions, only AMC was able to reduce the amount of dissolved HA, changing the surface charge of HA to positive. AMC improved the protective effect of F, but it did not affect FS. Polyoxirane and HPMC reduced the protective potential of the FS solution. No differences were found between the concentrations of the polymers. It was concluded that F and FS reduced the amount of dissolved HA. The protective effect of the experimental solutions against HA dissolution was polymer dependent. The F effect was enhanced by its combination with AMC, but the protection of FS was impaired by polyoxirane and HPMC.