bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical Properties and Melt Flow Index of Poly (butylene succinate) Blended with a Small Amount of Natural Rubber Compound
Authors: Singsang W , Rumjuan P , Ausungnoen Y , Charentanom W , Srakaew N , Prasoetsopha N 
Published: December 2020

AbstractNatural rubber compound (NRC) was blended with biodegradable poly(butylene succinate) (PBS) with PBS/NRC weight ratios of 100/0, 97/3, 94/6 and 90/10. The PBS/NRC blends were melt mixed using an internal mixer at 145°C. Mechanical properties and melt flow index of the blends were investigated. The results showed that the percentage elogation at break and impact strength of the blends impoved when NRC was added. On the other hand, the Young’s modulus and tensile strength of the blends decreased with an increase in the amount of NRC. The melt flow index of the blends continuously decreased with an increase in NRC content. This implied that NRC increased the viscosity of the blends. Moreover, the fractured surface morphology of PBS/NRC blends showed a good dispersion of NRC particles in PBS matrix. The average particle size of NRC was 2-5 μm.
Effect of poly(ethylene oxide) on the properties of poly(lactic acid)-based blends
Authors: Khanteesa R. , Threepopnatkul P. , Sittattrakul A. 
Published: December 2020

Abstract
Poly(lactic acid) (PLA) was blended with poly(ethylene oxide) (PEO) with four different molecular weights of 1 × 105, 2 × 105, 3 × 105, and 4 × 105 g/mol to improve the flexibility of PLA. The blends were compounded in an internal mixer at 190 °C with 50 rpm for 15 minutes and using a hot press to mold rectangular sample sheets. The mechanical properties of PLA blends were analyzed to prove the ductility. Additionally, phase morphologies of blends were investigated by using tensile fracture surface. The addition of PEO into PLA matrix leads to slight increase in tensile strength, while the elongation at break was decreased by increasing the molecular weight of PEO. However, the elongation at break of PLA/PEO blends was higher than the one of neat PLA. In other words, PEO enhanced the flexibility of PLA blends, according to scanning electron microscope images. In brief, PLA-based blends greatly increased in ductility.
The effect of rotor speed on EVA/PBAT blend using Twin screw extruder and foamability of EVA/PBAT blend
Authors: Thongpin Chanchai , Theanchai Kanyapak , Riangpha Pattama , Anantawut Weena 
Published: December 2020

Abstract
This research is aimed to study EVA/PBAT blends with various EVA and PBAT composition and screw speeds. At PBAT contents 40% EVA and PBAT present as co-continuous phase morphology. The morphology did not change due to screw speed. At PBAT 50% by weight, co-continuous phase occurred and the morphology becomes dispersed as screw speed was increased to 80 and 100 rpm. Extrudates obtained from twin screw extruder were tensioned under tensile force. The results show elastomeric behavior of the blends. Elongation at break was higher than 800 % strain and exhibited strain hardening characteristic. Secant modulus of EVA/PBAT blends was increased with PBAT contents due to the high modulus of semi-crystalline PBAT. Content of EVA controls elongation ability of the blends. EVA/PBAT blends with the content of 40/60, 50/50, 60/40, 70/30 and 80/20 were form for foam and found that all composition could be able to be foam. This could be further studied and carried on for shoes sole application.
Isolation and characterization of PLA-degrading bacteria from landfill soil at mesophilic temperature
Authors: Jalani J C , Arshad Z I M , Shaarani S Md , Che Man R , Abdul Mudalip S K , Sulaiman S Z 
Published: December 2020

Abstract
This study aimed to isolate and characterize polylactic acid (PLA) degrading bacteria present in landfill soils located in Pekan, Pahang. The conducted study involves collecting four soil samples from four different sources and stored at room temperature before undergoing serial dilution from dilution factor (DF) 10−1 until dilution factor 10−10. Characterization of bacteria via Gram staining was done only on isolates (69 colony) with DF 10-6 until DF 10-10 but only 13 isolates from plate with DF 10-8 and 10-10 were re-streaked to obtain single colony. The single colony obtained were further characterized for their morphological characteristics and tested for presence of protease enzyme by streaking the colony on skim milk agar which resulted with only four (A10K, A10B, B8A and D10A) showing positive presence of protease enzyme. The four plates were tested for catalase using 3%(v/v) hydrogen peroxide and all resulted with vigorous bubbling which indicate positive catalase enzyme. Relative enzyme activity was calculated for all four bacteria through observation of halo zones on skim milk agar, and isolate A10B shows the highest relative enzyme activity with 3.86, and thus showing potential to accelerate the degradation of PLA at mesophilic temperature. Therefore, in this study, it is proven to be possible to isolate bacteria that can degrade PLA at mesophilic temperature from landfill soil.
Ultrasonic assisted fermentation for production of xylanase enzyme using locally isolated strain of Bacilus badius
Authors: Masngut N , Rajandran P , Damanhuri N A 
Published: December 2020

Abstract
Ultrasonic assisted fermentation has been shown to improve the fermentation and product yield; however, less attention has been given to the xylanase production via ultrasonic assisted fermentation. The purpose of this study was to investigate the conditions in which ultrasonic has been employed to enhance fermentation reactions of interest to xylanase production. Previously, the xylanase production from locally isolated strain identified as Bacillus Badius was successfully carried out at an optimum condition. In this study, xylanase production was further explored by incorporated ultrasonic assisted fermentation. The study was conducted by varying the ultrasonic process parameters including treatment time, amplitude and duty cycle. Within the studied range, the highest xylanase production was 9.21 U/mL at duty cycle of 10 %, amplitude of 2 % and treatment time of 25 min. However, the production was 21 % lower than that the conventional optimized fermentation. This is due to unoptimized condition of the ultrasonic assisted fermentation as compared to the conventional one. Ultrasonication at the best process parameters is an effective and feasible way to enhance xylanase activity. In the future, we are looking forward to optimize the ultrasonic assisted fermentation to maximized xylanase production.
Comparative evaluation of the antibacterial activities of the essential oils of Citrus grandis (L.) Osbeck obtained by hydrodistillation and microwave assisted extraction methods
Authors: Tran T H , Dao T P , Ngo Q C T , Bach L G , Huynh X P 
Published: December 2020

Abstract
The essential oils (EOs) from peels of Citrus grandis (L.) Osbeck was investigated for their antimicrobial activities against food-related microorganisms by hydrodistillation method (HD), and microwave-assisted extraction (MAHD). The total yield of the volatile fractions obtained through HD and MAHD was 4.4 mL/g and 4.75 mL/g, respectively. The gas chromatography–mass spectrometry (GC–MS) analyses of the oils revealed the presence of different compounds in Citrus grandis EOs obtained from MAHD and HD methods, including α-pinene, sabinene, β-myrcene, α-phellandrene and d-limonene. The essential oils obtained from the two extraction methods were found to inhibit six bacteria strains including Bacillus cereus, Bacillus subtilis, Pseudomonas aeruginosa, E. coli, Clostridium perfringens and Salmonella typhi. The results of antibacterial properties of Citrus grandis (L.) Osbeck EOs against six bacterial strains showed that essential oil extracted from the HD method were more bacteriostatic than the oil extracted from MAHD method. With this result, the essential oil obtained by the HD method was more active than that of the MADH method against the bacteria.
Extraction of Essential oils and volatile compounds of Kaffir lime (Citrus hystrix D.C) by hydrodistillation method
Authors: Le X T , Ha P T H , Phong H X , Hien T T , Ngan T T K 
Published: December 2020

Abstract
Kaffir lime (Citrus hystrix D.C.), a member of the Citrus family, is a lemon tree naturally grown in tropical regions of Asia. Kaffir lime contains a specific aroma currently used worldwide as spices and cosmetics. Kaffir lime leaves are a famous spice for many dishes of Thai cuisine. The peel of Kaffir lime collected in the southwest of Vietnam was used for essential oil extraction using the process of hydro-distillation. During extraction, 100 g Kaffir lime peel was input at 1:3 ratio, at 120 °C for 90 min. The phytochemical profile of Kaffir Lime essential oil was analyzed by using gas chromatography/mass spectrometry (GC/MS) assay. The optimal essential oil yield reached 4.6%. A total of twenty-six components have been identified to account for 99.998% of essential oils. B-pinene (47.926%) was characterized as the main ingredient of peel oil. Other major components of Kaffir lime essential oil included D-limonene (24.121%), citronelal (11.84%), and α-pinene (2.834%). The present study evaluated the chemical compositions of Kaffir lime essential oil and compared with other previous studies. Future research on Kaffir lime EO can be expanded by using different extraction methods to improve its bioactive and applicability in many regions.
Phytochemicals and Antioxidant Activity of Aqueous and Ethanolic Extracts of Mentha aquatica L.
Authors: Thi N Q N , Duc L T , Minh L V , Tien L X 
Published: December 2020

Abstract
In Vietnam, Mentha aquatica L. is often used as a spice in dishes, fragrance and pharmaceuticals. The tea made from the plants’ leaves has been used as a traditional medicine for fevers, headaches, digestive disorders and mouthwash. The present study aimed to explore the phytochemical profile of aqueous and ethanolic extracts of M. aquatica L. leaves as well as their total phenolics content, total flavonoid content and antioxidant activity. Various bioactive constituents were detected in M. aquatica L. extracts, including alkaloid, flavonoid, terpenoid, tannin, coumarin, anthraquinone and saponin. Furthermore, the total content of phenolics of aquaeous extract was higher than ethanolic extract. We then evaluated the antioxidant capacity of these two extracts by using DPPH and ABTS scavenging assays. Results have shown that the aquaeous extract exhibited scavenging activity more actively against both free radicals, as compared to the aquaeous extract. Overall, the study proposed that M. aquatica L. leaves can be an enriched source of phytochemicals that can be used as natural antioxidants in multiple industries.
Chlorophyll content and antioxidant activity from folium sauropi (Sauropus androgynus (L.) Merr) with microwave-assisted extraction
Authors: Nguyen N H K , Tien H T C , Truc T T , Quoc L P T 
Published: December 2020

Abstract
Folium sauropi is grown commonly in Vietnam, it is a vegetable that contains many bio-active compounds such as chlorophyll, polyphenol, and antioxidant activity. The use of natural pigments having clear origin is a trend in food processing nowadays. The objective of this study was to find suitable conditions for extracting chlorophyll with antioxidant activity (DPPH) in folium sauropi leaves by microwave-assisted extraction. When extracted with acetone of 90°, microwave power of 300W, solid to solvent ratio of 1:30, microwave-assisted extraction time of 120 seconds; chlorophyll content (14.43± 0.16 μg/mL), and DPPH radical-scavenging activity (886.64± 15.89 μmol/L) obtained highest.
Comparison of chemical composition of essential oils obtained by hydro-distillation and microwave-assisted extraction of Japanese mint (Mentha arvensis L.) grown in Vietnam
Authors: Bui-Phuc T , Nhu-Trang T T , Cong-Hau N 
Published: December 2020

Abstract
The Japanese mint (Mentha arvensis L.) is known as a culinary and medicinal herb widely cultivated in several countries. The mint essential oil is considered as one main source of menthol. In this study, the Japanese mint collected from the Central Highlands of Lam Dong Province (Vietnam) was extracted the essential oil by hydro-distillation (HD) and microwave-assisted extraction (MAE). Different extraction parameters were investigated, involving mint leaf drying periods (30, 60, and 90 mins) at 50 °C, material to water ratios (1:4, 1:6, 1:8, and 1:10 for HD and 1:1, 1:1.5, 1:2, and 1:2.5 for MAE), extraction durations (60-180 for HD and 10-25 mins for MAE), and microwave energy (230, 380, 540, and 700 W) in order to discover the conditions with the highest yields for both HD and MAE. The GC-MS was used to determine the oil chemical constituents. For dried mint leaves (nearly 40 % moisture), the highest oil yield of 0.0832 mL g−1 (dried weight) was recorded, and the content of menthol was up to 70.60 % extracted by MAE whilst 0.0510 mL g−1 of yield (dried weight) and lower menthol (62.80 %) were obtained from HD. Besides, menthol, trans- and cis-menthone were found at relatively high concentrations for both HD and MAE (20.19-16.30 and 4.62-5.01 %, respectively). Compared to HD, MAE exhibited higher oil yields and menthol contents, but lower distillation time, resulting in more effective extraction performance of MAE.
Determination of structure and anticancer activity of MM2 compound, isolated from endophytic fungus Aspergillus terreus-RTN3 of Alpinia chinensis Rosc.
Authors: Vo T N M , Nguyen D N , Nguyen V T 
Published: December 2020

Abstract
The study has isolated endogenous A. terreus-RTN3 strain from young stems of Alpinia chinensis Rosc.-Zingiberaceae family. Cultivating and extracting compounds containing metabolites that are resistant to Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus (MRSA). Determining the number of antibacterial compounds in the crude extract by thin-layer chromatography and vacuum liquid chromatography (VLC), the research has isolated pure MM2 compound with high antioxidant activity and spectral resolution to find the structure compound MM2 (Methyl 2-((4-amino-2-bromo-3-methyl-5-thioxocyclopenta-1,3-dien-1-yl) oxygen) -4-hydroxy-6-methoxybenzoate). This is a new compound that has not been announced in any works in the world. MM2 compound has a high antioxidant activity, the ability to catch α, α-diphenyl-β-picrylhydrazyl (DPPH) free radicals increases linearly by concentration, at concentration 400ppm of MM2 is capable of catching over 75% of DPPH free radicals. The MM2 compound also has the ability to inhibit 4 test cell lines: breast cancer (MCF-7), cervical cancer (Hela), liver cancer (Hep G2) and lung cancer (NCI-H460). The results showed that MM2 compound’s ability to inhibit cancer cell lines increased linearly, at concentrations of 100 µg/ml of MM2 compound, which inhibited nearly 80% of cancer cell lines and was high most in liver cancer cell line HepG2 (at a concentration of 100 µg/ml inhibits 86.82% of liver cancer cells HepG2).
Isolation and determination of FUB-AMB in synthetic cannabinoids by gas chromatography-mass spectrometry
Authors: Nguyen T A , Lam T D , Nguyen T Đ 
Published: December 2020

Abstract
N-[[1-[(4-fluorophenyl)methyl]-1H-indazol-3-yl]carbonyl]-L-valine, methyl ester (FUB-AMB) is the most recent psychoactive substance in Vietnam. FUB-AMB is a synthetic cannabinoid (SC) with has similar biological effects to tetrahydrocannabinol (THC), the main active component of natural cannabis. The previous study exhibits a harmful SC compound, which may cause many threatening to consumer health and social security due to the intensive effect of this compound on the mental status and behavior of the consumer. In this study, FUB-AMB was isolated the first time in Vietnam (1 g) with a purity of 98.34% (determined by High Performance Liquid Chromatography). Spectroscopic data (ultraviolet, infraRed 1Hydro - nuclear magnetic resonance, 13carbon - nuclear magnetic resonance) confirmed the structure of that isolated compound. The isolated FUB-AMB was used as a reference standard to develop an analytical method to detect drugs in the general marijuana group. Chromatography separation was achieved using a diphenyl dimethyl polysiloxane Gas chromatography (GC) column (30m×0.25mm×0.25µm) with a total run time of 10 minutes. The limits of detection and quantification for FUB-AMB was 0.15 μg/mL and 0.5 μg/mL, respectively. The developed method was used to detect FUB-AMB in synthetic cannabinoids in 30 samples. The results showed that the content of FUB-AMB ranged from 3.4-59.2 mg/g in 30 synthetic cannabinoids. The advanced GC-MS method is simple, sensitive, accurate and practically useful for the determination of FUB-AMB in synthetic cannabinoids, which supports the authorities’ crime handling.
Physicochemical, Physical Characteristics and Antioxidant Activities of Three Edible Red Seaweeds (Kappaphycus alvarezii, Eucheuma spinosum and Eucheuma striatum) from Sabah, Malaysia
Authors: Farah Nurshahida M S , Nazikussabah Z , Subramaniam S , Wan Faizal W I , Nurul Aini M A 
Published: December 2020

Abstract

Kappaphycus alvarezii (KA), Eucheuma spinosum (ESp) and Eucheuma striatum (Est are tropical red seaweeds taken from Kunak, Sabah, contain essentials source of bioactive compounds to produce variety of functional foods. This study was intended to investigate the physicochemical, physical properties and antioxidant activities related to these edible seaweeds. Physicochemical properties value of swelling capacity (SWC) and oil retention capacity (ORC) in KA species showed the highest value (p<0.05) compared to ESp and ESt, and water retention capacity (WRC) in ESp species was significantly different than KA and ESt (p<0.05). As in physical properties, ESp exhibited higher in moisture content and opacity than KA and ESt. KA showed the highest water solubility (p<0.05) which associated to its carrageenan compound. The antioxidant activities; DPPH and TEAC assay with total phenolic content (TPC) of three seaweed species indicated that KA displayed the highest TPC (19.17±0.04 mg GAE/g DW) and the lowest radical scavenging activity in both TEAC and DPPH assays. Hence, the findings disclose the physical and physiochemical properties and antioxidant values of these seaweeds application as new information and potential antioxidant sources in foods manufacturing commodities.
Comparison of essential oil extracted from black pepper by using various distillation methods in laboratory scale
Authors: Dinh P N , Cam H D T , Quoc T P 
Published: December 2020

Abstract
Black pepper is an indispensable spice in life—pepper oil used in various fields as pharmaceutical, cosmetic, repellent. Black pepper was picked in Vietnam and its essential oil was obtained by distillation methods. This study investigated the effect of several parameters such as material/water ratio, distillation time, the weight of the sample, and extraction power on the yield and the quality of black pepper essential oil from three distillation methods. The results showed that the hydrodistillation method reached the highest yield of 2.19% at conditions of 60 minutes extraction time and material/water ratio of 1:15 g/mL compare to the steam distillation method and microwave assisted hydrodistilation method. GC-MS analysis resulted in the identification of 70 components accounting for 99% of the total amount: β-caryophyllene, 3-carene, D-limonene, and β-pinene, are among the main compounds in black pepper essential oil.
Production of cellulose and microcellulose from pineapple leaf fibre by chemical-mechanical treatment
Authors: Gnanasekaran S , Li Y Y , Shariffuddin J H , Ahamad Nordin N I Amalina 
Published: December 2020

Abstract
Pineapple leaf fibre (PALF) is major waste from pineapple cultivation with high cellulose content that exhibits superior mechanical properties. In this study, chemical-mechanical treatments were conducted to produce cellulose and microcellulose. For alkali and steam treatment, PALF treated with 5 wt% sodium hydroxide solution and steamed in an autoclave at temperature of 121 °C and pressure of 21 psi. Next, the PALF was bleached with 5 wt% sodium chlorite. Continued with acid hydrolysis with 3.5 M and 7.5 M hydrochloric acid to produce cellulose. For, the mechanical treatment which involved homogenization and ultrasonication to produce the microcellulose, the ultrasonication was varied for 30 and 60 min. The samples were analysed by Scanning Electron Microscopy, Thermal Gravimetric Analysis and Fourier Transform Infrared Spectroscopy (FTIR) to study surface morphology, thermal stability and functional group respectively. The results showed that ABAHU60 with alkali treatment, bleaching, acid hydrolysis, homogenization and ultrasonication of 60 min exhibits excellent thermal stability and surface morphology, where the maximum degradation temperature occurs at 349 °C, which is a 5% improvement compare to untreated fibre. Its surface is smoother without impurities, with a loose structure and reduce diameter of fibre.
Dilute acid hydrolysis pretreatment for sugar and organic acid production from pineapple residues
Authors: Ariffin K K , Masngut N , Seman M N A , Saufi S M , Jamek S , Sueb M S M 
Published: December 2020

Abstract
Pineapple residue which is pineapple leaves composed of about 80% of carbohydrate containing lignin, cellulose and hemicellulose was utilised for the production of fermentable sugars. However, pretreatment of lignocellulosic material is required to remove hemicellulose and lignin and reducing crystallinity of cellulose to enhance hydrolysis. This paper presents an experimental study of acid hydrolysis pretreatment in pineapple residue to produce sugar and organic acid using sulphuric acid. The effect of different acid concentration (4%, 8% and 12% v/v), solid-to-liquid ratio (10%, 15% and 20% w/v) and reaction time (40, 80, and 120 minutes) of acid hydrolysis pretreatment on pineapple residue at temperature of 100°C were studied to produce high yield of sugar and low organic acid production. As a result, the highest of sugar concentration simultaneously with the lowest of organic acids concentration from pineapple residue were 2.68 ± 0.12 g/L (xylose), 8.84 ± 0.11 g/L (glucose), 1.62 ± 0.20 g/L (formic acid) and 3.28 ± 0.26 g/L (acetic acid); recorded at conditions of 12% acid concentration (v/v), 20% solid-to-liquid ratio and 80 minutes of reaction time. In conclusion, dilute acid hydrolysis pretreatment was a great approach in order to produce high sugar at the same time with low organic acids yield from pineapple residue at mild conditions.
Evaluation of Antibacterial Activity of fractions from stem extract of Tinospora crispa (L.) Hook. f. & Thomson
Authors: Pham T N , Nguyen T V 
Published: December 2020

Abstract
The aim of this study is to evaluate the antibacterial activity of fractions from Tinospora crispa (L.) Hook. f. & Thomson stem extract. The extraction was fractionated by solvents with increasing polarity, then partioned with acidic water and base to concentrate alkaloids. There are totally 7 fractions named PD-hex, PD-K, PD-Cf2, PD-Cf1, PD-EtOAc, PD-BuOH and PD-N. With the help of disc diffusion method, 7 fractions were separately evaluated for their ability to inhibit the growth of some common bacterial species, including 3 Gram-positive and 3 Gram-negative bacteria. The result showed that Tinospora crispa was able to restrain the growth of the 3 Gram-positive species but not the 3 Gram-negative species. Antibacterial substances distributed in 6 over 7 fractions tested, excluding PD-K fraction. PD-K sample mainly contained strong basic alkaloid and soluble water. Especially, weak basic alkaloids in PD-Cf2 were able to restrict the bacterial growth stronger than stronger basic alkaloids in PD-K. On the other hand, ethyl acetate fraction (PD-EtOAc), which contained medium polar compounds, were able to restrict the growth of bacteria slightly better than the others. It was subjected to traditional column chromatography to isolate some components. The purified substance was structurally identified by thin-layer chromatography, high performance liquid chromatography and spectroscopic data analyses.