Periodico Tche Quimica最新文献

{"title":"EVALUATION OF THE CONTACT SURFACE PARAMETERS AT KNURLING FINNED HEAT-EXCHANGING SURFACE BY KNURLS AT RING BLANKS","authors":"A. Tatarkanov, I. Alexandrov, A. Olejnik","doi":"10.52571/ptq.v17.n36.2020.387_periodico36_pgs_372_389.pdf","DOIUrl":"https://doi.org/10.52571/ptq.v17.n36.2020.387_periodico36_pgs_372_389.pdf","url":null,"abstract":"\u0000Tubular parts with an external finned heat-exchanging surface are usually produced by the laborious method of cutting on lathes. Besides, there is a method for the high-performance manufacturing of fins by cold knurling with ring-cut knurls, which, compared with cutting, reduces labor intensity by two to six times with a significant increase in the operational properties of the product. The disadvantage of the cold knurling method with ring-cut knurls can be unwanted surface defects and deformations of the entire product. Obtaining finned surfaces on ring blanks with high surface quality during knurling requires accurate calculation of the ratio of longitudinal and transverse strains. The most important factors determining the ratio of longitudinal and transverse strains (rolling-out and rolling-off) are the length and width of the contact surface. The need for a quantitative assessment of the parameters of longitudinal and transverse strains determined the purpose of this manuscript. This study aimed to develop a methodology for calculating the contact surface of a knurl with a ring blank (pipe) when knurling with ring-cut knurls. The proposed method for calculating the knurl's contact surface with a tube when knurling with ring-cut knurls allows for estimating the recommended range of pipe sizes for knurling. Based on the dependencies mentioned in the manuscript, the limiting sizes for blank pipes were calculated to ensure high-quality finning. Experiments on cold rolling of ribbing on pipes with different lengths and diameter ratios were carried out, confirming the possibility of using the proposed methodology for calculating the knurl's contact surface with a pipe when knurling heat-exchanging finning with ring-cut knurls.\u0000","PeriodicalId":45103,"journal":{"name":"Periodico Tche Quimica","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42348471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"RADIATION DOSE RATE MEASUREMENT FOR PROTECTION PROGRAMS IN THE WORK ENVIRONMENT FOR THE HEALTH WORKERS: AN EXPERIMENTAL STUDY","authors":"Ramacos Fardela, G. Suparta, Ahmad Ashari, K. Triyana","doi":"10.52571/ptq.v17.n36.2020.677_periodico36_pgs_662_673.pdf","DOIUrl":"https://doi.org/10.52571/ptq.v17.n36.2020.677_periodico36_pgs_662_673.pdf","url":null,"abstract":"\u0000Radiation is the energy emitted from electrons in particles or photons (waves) and is classified into nonionized and ionized. Ionizing radiation demonstrates the ability to disintegrate matter along its path and has proven beneficial in medicine. Exposure to this energy tends to instigate adverse effects on human health and heredity (genetics). However, the radiation is not directly measured but requires a nuclear detector to serve as a monitoring device. Radiation workers’ awareness of ionizing radiation levels in the work environment is one of the most important factors in preventing the negative effects of radioactivity. This is possibly identified using various types of detectors. This experiment aimed to provide an overview of radiation dose rate measurement under two conditions. First is the event of contamination in the work environment. The second involves using a detector to solely determine the dose rate from a single source, e.g., gamma radiation. Therefore, the radiation dose rate\u0000was evaluated by maximizing the use of detectors with a GUI as a survey meter for contamination. The highest rate (261.42 μSv / h) was observed at a distance of 5 mm, while the least (69.21 μSv / h) was recorded at 50 mm. Also, a dose rate of 5.4 μSv / h and 1.32 μSv / h was obtained at a 5 mm and 50 mm distance from the radiation source, respectively, following the operation as a gamma survey meter. This result shows strong linearity between both measurements and is estimated to accurately determine the contamination level of radioactive elements, alongside the doses rate of the gamma radiation emitting elements.\u0000","PeriodicalId":45103,"journal":{"name":"Periodico Tche Quimica","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45335225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"DEVELOPMENT OF CALIBRATION GAS MIXTURES (CARBON DIOXIDE AND OXYGEN IN NITROGEN MATRIX) AT A TYPICAL CONCENTRATION RANGE OF MODIFIED ATMOSPHERE PACKAGING","authors":"A. Hindayani, Muhammad Rizky Mulyana, H. Budiman, N. T. E. Darmayanti, Oman Zuas","doi":"10.52571/ptq.v17.n36.2020.689_periodico36_pgs_674_687.pdf","DOIUrl":"https://doi.org/10.52571/ptq.v17.n36.2020.689_periodico36_pgs_674_687.pdf","url":null,"abstract":"\u0000Measurement of carbon dioxide (CO2), oxygen (O2), and nitrogen (N2) concentration in modified atmosphere packaging (MAP) food is critical to be carried out by the food industry. A slight variation in concentrations of CO2, O2, and N2 in food packaging may have a significant impact on product quality and safety for human health. Accurate and reliable measurement of CO2, O2, and N2 concentrations in food packaging is crucial, and it can only be achieved by calibrating the gas analyzer. This study aimed to develop gas mixtures for the calibration of CO2, O2, and N2 gas analyzers at a typical concentration range of modified atmosphere packaging. The calibration gas mixtures were prepared gravimetrically by following ISO 6142. The concentration ranges of CO2, O2, and N2 for calibration gas mixtures were set at 9-19% mol/mol, 1-5% mol/mol, and 74-88%\u0000mol/mol, respectively. Each parent gas was identified for its impurities using gas chromatography with a pulsed discharge helium ionization detector (GC-PDHID). The compositions of CO2, O2, and N2 in the mixtures were verified by evaluating the internal consistency within the prepared gas mixtures using gas chromatography with a thermal conductivity detector (GC-TCD). The short term stability of the prepared gas mixtures was evaluated using an equal division method. The result showed that good internal consistency was achieved between the gravimetrical and GC’s verification values, having linear regression coefficient (R2) ≥ 0.999. The t-test result has shown that CO2 has better short term stability than O2 and N2. In conclusion, the developed calibration gas mixtures at a typical concentration range of modified atmosphere packaging have shown satisfying results for CO2 component. However, further evaluation is still required to minimize the instability of O2 and N2 components.\u0000","PeriodicalId":45103,"journal":{"name":"Periodico Tche Quimica","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48176085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CHANGE OF THE CHEMICAL, FAT AND ACID COMPOSITION AND PHYSICAL AND TECHNICAL PROPERTIES OF LAMB FAT UNDER INFLUENCE OF VARIOUS FODDER BACKGROUND","authors":"I. Mironova, Z. Galieva, I. Gazeev, Alexander Belousov, Venire Galimova","doi":"10.52571/ptq.v17.n35.2020.08_mironova_pgs_83_92.pdf","DOIUrl":"https://doi.org/10.52571/ptq.v17.n35.2020.08_mironova_pgs_83_92.pdf","url":null,"abstract":"The role of fats in nutrition is determined by their high-calorie content and participation in the construction of body tissues, together with proteins and carbohydrates. Enriched nutrition is of great importance in the complex of issues that determine its usefulness. Thus, the question of the effect of probiotics and sorbents in the diet on the animal organism has become very relevant. The purpose of the work was a comparative assessment of the composition and properties of adipose tissue of rams, consuming together and separately preparations with sorption and probiotic effect. The studies were carried out in two stages. In the first, during the scientific and economic experiment, 80 newborn rams grew and developed up to a year of age, followed by the slaughter of three animals from each group. In the second stage, samples of internal fat were examined according to some indicators. Sensory analysis revealed that all internal fat samples met the established requirements, while the color and consistency of the experimental samples improved. The dry matter content, including fat in the experimental samples of fat tissue, increased, and moisture decreased. The physical and technical parameters of internal fat also changed in the intergroup aspect. In the control sample, the iodine number decreased, and the saponification number, pour point, and melting point increased. Calculation of energy value indicates that in the first sample, the indicator increased by 0.08 MJ (0.23%); Group II – by 0.16 MJ (0.45%) and group III – by 0.25 MJ (0.70%). According to the sum of monounsaturated fatty acids, young group III was in the lead. The content of polyunsaturated fatty acids was the opposite. The biological effectiveness of fats is determined by the ratio that was better in the experimental samples. Thus, the inclusion of fodder additives in the diet of the rams of the Romanov breed helps to improve the quality of raw materials.","PeriodicalId":45103,"journal":{"name":"Periodico Tche Quimica","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48864691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CRITERIA-BASED ASSESSMENT AS THE WAY OF FORMING STUDENTS FUNCTIONAL LITERACY IN COMPUTER SCIENCE","authors":"S. Avdarsol, L. Rakhimzhanova, B. Bostanov, Ainur Ye. Sagimbaeva, Tiyshtik Khakimova","doi":"10.52571/ptq.v17.n35.2020.04_avdarsol_pgs_41_54.pdf","DOIUrl":"https://doi.org/10.52571/ptq.v17.n35.2020.04_avdarsol_pgs_41_54.pdf","url":null,"abstract":"For a long time, the primary approach to assessment was the normative approach when the individual achievements of students were compared with a particular norm (the results of most students). Recently, domestic pedagogical research has been developing a criteria-based approach to assessing academic achievement when students' achievements are compared with the amount of knowledge that needs to be acquired at a particular stage of training. This study aimed to determine the role of criteria-based assessment in the formation of students functional literacy in computer science and to build a criteria-based assessment model in the development of functional literacy beyond to demonstrate the effectiveness of the methods of formation of students functional literacy in computer science. The leading research methods were the criteria-based assessment methodology developed by the authors and the method of formative assessment. Some elements of the methodology of forming evaluation were considered. For further development of the methods for the formation of students functional literacy in computer science, a criteria-based assessment model has been built. The introduction of criteria-based assessment will allow to switch to a formative evaluation aimed at developing student competence. The evaluation, consisting of criteria that a student understands, stimulates him and makes the learning process meaningful. Based on practical experiments and the proposed criteria-based assessment, the effectiveness of methods for the formation of students functional literacy in computer science has been proved.","PeriodicalId":45103,"journal":{"name":"Periodico Tche Quimica","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44332779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"TECHNICAL INVESTIGATION OF SEA SAND REINFORCEMENT FOR NOVEL AL6061- SEA SAND COMPOSITES: IDENTIFICATION OF PERFORMANCE AND MECHANICAL PROPERTIES","authors":"H. Akbar, E. Surojo, D. Ariawan, A. Prabowo","doi":"10.52571/ptq.v17.n36.2020.63_periodico36_pgs_47_57.pdf","DOIUrl":"https://doi.org/10.52571/ptq.v17.n36.2020.63_periodico36_pgs_47_57.pdf","url":null,"abstract":"\u0000Lightweight materials with low-cost production have been developed in recent years. The addition of ceramics and oxide particles such as Al2O3, SiC, and SiO2 has been improving in the mechanical properties of aluminum matrix composites (AMCs). As a solution, the use of natural reinforcing material continues to investigate. This paper investigates sea sand as an alternative reinforcement to AMCs. The Al 6061 was used as the matrix and sea sand as reinforcement. The manufacturing of the composite was conducted by stir casting route with variation 0, 2, 4, 6 %wt of the reinforcement. The composite was tested in hardness and tensile strength, the hardness test was obtained according to ASTM E-10, and the tensile test was conducted according to JIS Z2201 standard. Composite density decreases linearly with the addition of the reinforcement from 2 %wt to 6%wt, and the same phenomenon is obtained in porosity, the porosity increases with the addition of sea sand particles from 2%wt to 6%wt. The decline in density due to the lower density of sea sand particles compared to the aluminum matrix. Higher the sea sand particle that disperses into the matrix resulted in a lower density of the composite. Increasing porosity caused a higher fraction of reinforcement resulting in wider surface contact between matrix and reinforcement that promote the porosity. The hardness and ultimate tensile strength of AMCs increase with increasing of sea sand particles content. The presence of an oxide compound on the sea sand increased the mechanical properties of the composite. Increasing in mechanical properties indicate the sea sand particle dispersed into the matrix and sea sand can be used as engineering purpose material.\u0000","PeriodicalId":45103,"journal":{"name":"Periodico Tche Quimica","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46044790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"DEVELOPMENT OF SPECIAL CHEMISTRY SKILLS IN THE UNIVERSITY VOCATIONAL TRAINING SYSTEM OF THE STUDENTS","authors":"N. N. Maslennikova, I. Gibadulina, E. A. Gafiyatullina","doi":"10.52571/ptq.v17.n36.2020.1142_periodico36_pgs_1127_1147.pdf","DOIUrl":"https://doi.org/10.52571/ptq.v17.n36.2020.1142_periodico36_pgs_1127_1147.pdf","url":null,"abstract":"\u0000Preparing students for work in the field of education contributes to the development of school education. The basis for teaching students is made up of techniques, methods, and forms of learning by practical activity and the implementation of professional actions. The use of information and communication technology (ICT) in higher education contributes to the disclosure, preservation, and development of individual interests; the motivation; the desire for self-improvement and self-realization of students; ensuring the complexity of studying the phenomena of reality, the inextricability of the relationship between science, technology, the humanities, and art; a constant dynamic update of the content, means, forms, and methods of training and education. This study aimed to identify the level of future chemistry teachers through ICT competence development. A survey was conducted among 24 teachers of general professional and subject-vocational training, who taught “Chemical Technology” to their students. The questionnaire was targeted; the questionnaires were used both in electronic format (Google form) and in print. The article shows how information competence for future chemistry teachers is developed. The practical significance of the study is determined by the need to match the level of school education with modern technological trends. It is shown that there is a necessity for the motivation of students in scientific activity. It was established that the acquisition of competencies and the experience in open training systems, according to all respondents, is a prerequisite for the implementation of further effective educational, cognitive, and professional activities. The ascertaining stage of the pedagogical experiment established the need to choose and introduce the disciplines of mobile, computer, and cloud technologies into the curriculum for solving professionally-oriented problems. The novelty of the study is determined by the necessity to increase the competence of the pedagogical university students in training how to teach chemical disciplines.\u0000","PeriodicalId":45103,"journal":{"name":"Periodico Tche Quimica","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42064852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"ERROR ESTIMATION OF THE ALGORITHM FOR THE PHASE SHIFT DEFINITION OF HARMONIC SIGNALS IN THE TIMELESS THAN THE SIGNAL PERIOD USING STOCHASTIC SAMPLING","authors":"I. Zaitseva","doi":"10.52571/ptq.v17.n36.2020.229_periodico36_pgs_213_222.pdf","DOIUrl":"https://doi.org/10.52571/ptq.v17.n36.2020.229_periodico36_pgs_213_222.pdf","url":null,"abstract":"\u0000Determining the parameters of a harmonic signal is one of the most common types of measurements in radio engineering, communication engineering, electronics and automation systems. The research and development of new methods for measuring the harmonic signal parameters are relevant. This work studied algorithm errors for determining the phase shift of harmonic signals using stochastic sampling. The relevance of this study is dictated by increasing requirements for the accuracy and speed of measuring equipment, the reduction of time it takes to decide on the presence of a signal while searching for it, that make it necessary to use statistically optimal methods for measuring signal parameters. The work aimed to develop an algorithm and estimate its errors for the possibility of practical implementation of the algorithm for processing infra-lowfrequency radio signals during stochastic sampling. According to the uniform distribution law, the instantaneous values in each sample of the signals under investigation are based on stochastic sampling in time. Mathematical modeling of algorithm errors for determining the phase shift of signals with harmonics, and depending on harmonics compared to the first (main) harmonic of the signal under investigation during the sampling by real analog-to-digital converters have been carried out. The obtained values of the algorithm errors for determining the phase shift of the main harmonic are within an acceptable range (30%); at harmonics amplitudes (up to the 3rd harmonic) within 20%. The computing experiment results for estimating the algorithm errors confirm the possibility of obtaining high accuracy in determining the phase shift of harmonic signals. This algorithm can be used for processing infra-low-frequency radio signals with sufficient accuracy in acoustics, hydroacoustics, seismic acoustics, underwater, and underground communication.\u0000","PeriodicalId":45103,"journal":{"name":"Periodico Tche Quimica","volume":"1 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70710136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"EVALUATION OF VITAMIN D3 AND ZINC LEVELS IN IRAQI CHILDREN WITH GROWTH HORMONE DEFICIENCY AND THEIR RELATION WITH OTHER BIOCHEMICAL PARAMETERS","authors":"I. Q. Falih, N. Tahir, Walaa Ahmed Al Jedda","doi":"10.52571/ptq.v17.n36.2020.491_periodico36_pgs_476_490.pdf","DOIUrl":"https://doi.org/10.52571/ptq.v17.n36.2020.491_periodico36_pgs_476_490.pdf","url":null,"abstract":"\u0000Growth hormone deficiency (GHD) is suspected in subjects with short stature (SS) and decreased growth velocity in whom other causes of low growth have been excluded. The growth hormone itself has a direct stimulatory action on the production of vitamin D3. Both vitamin D and growth hormone metabolism influences each other. Zinc level also plays an essential regulator of bone growth and potential growth pathway. A total of 50 children aging 4-12 years old with growth hormone deficiency have participated in this study. They were compared with 38 healthy children as a control group. This study was conducted during the period from September 2019 to June 2020. The patients were attending the National Diabetic Center/ AL-Mustansiriyah University, Baghdad, Iraq. Growth hormone, insulin-like growth factor-1, thyroid function test, cortisol level, vitamin D3, zinc level, fasting blood sugar, and lipid profile were measured in children with growth hormone deficiency. A nonsignificant difference was found in basal growth hormone between patients of growth hormone deficiency and control. There was a highly significant decrease in growth hormone level after 1 hour (provocation with clonidine) (p 0.001) and a significant decreased in growth hormone level after 1:30 hours (provocation with clonidine) (p 0.01) in patients of growth hormone deficiency compared to the control group. Also, it was observed a highly significant decrease (p 0.001) of insulin-like growth factor-1 levels in growth hormone deficiency patients when compared to control. It was also observed that there was a significant decrease (p 0.001) in the levels of Zn and vitamin D in patients with growth hormone deficiency compared to the control in addition to the distribution of the levels of vitamin D and Zinc have increased more in women than in men. It can be concluded that there was a highly significant decrease in vitamin D and Zn levels in patients with growth hormone deficiency compared to the control group. The deficiency of vitamin D and zinc levels may play an essential role in the pathogenesis of growing children with a growth hormone disorder.\u0000","PeriodicalId":45103,"journal":{"name":"Periodico Tche Quimica","volume":"1 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70710282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"DERIVATIZATION OF CHLOROPHYLL FROM PANDAN (Pandanus amaryllifolius Roxb.) LEAVES AND THEIR ANTIOXIDANT ACTIVITY","authors":"C. L. Suryani, T. Wahyuningsih, A. Supriyadi, U. Santoso","doi":"10.52571/ptq.v17.n36.2020.1125_periodico36_pgs_1110_1126.pdf","DOIUrl":"https://doi.org/10.52571/ptq.v17.n36.2020.1125_periodico36_pgs_1110_1126.pdf","url":null,"abstract":"\u0000Chlorophyll is a natural coloring agent that has antioxidant activity. During the extraction and food processing process, chlorophyll is easily degraded and derivatized. The derivatization process results in changes in the chemical structure of chlorophyll which can result in a change in color and its antioxidant activity. The other extracted minor compounds can affect its antioxidant activity. This study aimed to identify the chemical structure changes of chlorophyll extracted from pandan (Pandanus amaryllifolius Roxb) leaves as affected by the derivatization process and evaluate the antioxidant activity of the extracts and fractions of chlorophyll and its derivatives. Chlorophyll was extracted from pandan leaves with acetone, derivatized, and then purified by fractionation using column chromatography. Chlorophyll extract and its derivatives were analyzed for total carotenoid, total phenolic, and flavonoid contents. The antioxidant activity of extract and fraction was measured by the inhibition of peroxidation of linoleic acid, radical scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing/ antioxidant power (FRAP) ability, and metal chelating assay. Based on the FTIR and MS/MS spectra, it was observed that the first derivatives were pheophytin and chlorophyllide, while the second derivative was pheophorbide. The other extracted compounds, including phenolic compounds, flavonoids, and carotenoids, might enhance the antioxidant activity of the chlorophyll derivatives. The inhibition rate of linoleic acid peroxidation by chlorophyll, chlorophyllide, and pheophorbide extract was not significantly different from BHT, where pheophytin extract was lower. The radical scavenging activity of DPPH and FRAP assay showed that chlorophyll and chlorophyllide extracts exhibited higher activity, followed by pheophytin and pheophorbide. Meanwhile, the metal chelating assay showed that chlorophyllide fraction exhibited the lowest activity. Therefore, the antioxidant activity of the first derivatives of chlorophyll was higher than the second derivatives. In general, the extract of chlorophyll and its derivatives exhibited higher antioxidant activity than that of their fraction.\u0000","PeriodicalId":45103,"journal":{"name":"Periodico Tche Quimica","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46665881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}