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The management of insect pests and fungal diseases that cause damage to crops has become challenging due to the rise of pesticide and fungicide resistance. The recent developments in studies related to plant-derived essential oil products has led to the discovery of a range of phytochemicals with the potential to combat pesticide and fungicide resistance. This review paper summarizes and interprets the findings of experimental work based on plant-based essential oils in combination with existing pesticidal and fungicidal agents and novel bioactive natural and synthetic molecules against the insect pests and fungi responsible for the damage of crops. The insect mortality rate and fractional inhibitory concentration were used to evaluate the insecticidal and fungicidal activities of essential oil synergists against crop-associated pests. A number of studies have revealed that plant-derived essential oils are capable of enhancing the insect mortality rate and reducing the minimum inhibitory concentration of commercially available pesticides, fungicides and other bioactive molecules. Considering these facts, plant-derived essential oils represent a valuable and novel source of bioactive compounds with potent synergism to modulate crop-associated insect pests and phytopathogenic fungi.
Mackingsley Kushan Dassanayake; Chien Hwa Chong; Teng-Jin Khoo; Adam Figiel; Antoni Szumny; Chee Ming Choo. Synergistic Field Crop Pest Management Properties of Plant-Derived Essential Oils in Combination with Synthetic Pesticides and Bioactive Molecules: A Review. Foods 2021, 10, 2016 .
AMA StyleMackingsley Kushan Dassanayake, Chien Hwa Chong, Teng-Jin Khoo, Adam Figiel, Antoni Szumny, Chee Ming Choo. Synergistic Field Crop Pest Management Properties of Plant-Derived Essential Oils in Combination with Synthetic Pesticides and Bioactive Molecules: A Review. Foods. 2021; 10 (9):2016.
Chicago/Turabian StyleMackingsley Kushan Dassanayake; Chien Hwa Chong; Teng-Jin Khoo; Adam Figiel; Antoni Szumny; Chee Ming Choo. 2021. "Synergistic Field Crop Pest Management Properties of Plant-Derived Essential Oils in Combination with Synthetic Pesticides and Bioactive Molecules: A Review." Foods 10, no. 9: 2016.
The preservation of herbs during post-harvest operations is crucial in maintaining their potency. The preservation of Malaysian rosemary (Rosmarinus officinalis L.) was investigated by determining the effect of various drying processes on active volatile components and their respective bioactivities. The drying processes included convective drying at 50, 60, and 70 °C; freeze-drying; vacuum-microwave drying (VMD) at 240, 360, and 480 W; and combination of convective pre-drying (CPD) for 30, 60, and 120 min followed by vacuum-microwave finish drying (VMFD) at 360 W. Complete moisture removal was achieved the fastest by VMD at the highest wattage. Semi-theoretical models, namely, modified Henderson–Pabis, Page, and modified Page had the best prediction accuracy of drying kinetics with the highest R2 (>0.9704) and the lowest RMSE (<0.0565). Sixty-seven compounds were identified from fresh and dried rosemary leaves with camphor (1.45 g kg−1 DW), α-pinene (1.64 g kg−1 DW), and α-terpineol (1.79 g kg−1 DW) as the dominant volatiles. The highest volatile percentage, phenolic content, and antioxidant activities were determined from convective-dried leaves at 60–70 °C, whereas the best anti-diabetic and anti-aging effects were detected from freeze-dried leaves. Non-identified compounds probably have a substantial contribution to the bioactivities of freeze-dried leaves. VMD at 480 W was the most efficient method with the least energy consumption. The sequential method of CPD-VMFD performed moderately among the investigated processes in all aspects. Future studies should further improve the drying processes and investigate the nonvolatile fraction of dried rosemary.
Ameena Ali; Choo Choong Oon; Bee Lin Chua; Adam Figiel; Chien Hwa Chong; Aneta Wojdylo; Igor Piotr Turkiewicz; Antoni Szumny; Jacek Łyczko. Volatile and polyphenol composition, anti-oxidant, anti-diabetic and anti-aging properties, and drying kinetics as affected by convective and hybrid vacuum microwave drying of Rosmarinus officinalis L. Industrial Crops and Products 2020, 151, 112463 .
AMA StyleAmeena Ali, Choo Choong Oon, Bee Lin Chua, Adam Figiel, Chien Hwa Chong, Aneta Wojdylo, Igor Piotr Turkiewicz, Antoni Szumny, Jacek Łyczko. Volatile and polyphenol composition, anti-oxidant, anti-diabetic and anti-aging properties, and drying kinetics as affected by convective and hybrid vacuum microwave drying of Rosmarinus officinalis L. Industrial Crops and Products. 2020; 151 ():112463.
Chicago/Turabian StyleAmeena Ali; Choo Choong Oon; Bee Lin Chua; Adam Figiel; Chien Hwa Chong; Aneta Wojdylo; Igor Piotr Turkiewicz; Antoni Szumny; Jacek Łyczko. 2020. "Volatile and polyphenol composition, anti-oxidant, anti-diabetic and anti-aging properties, and drying kinetics as affected by convective and hybrid vacuum microwave drying of Rosmarinus officinalis L." Industrial Crops and Products 151, no. : 112463.
The combined chemical and natural coagulant showed greater fluoride ion removal in synthetic hydrofluoric acid wastewater when compared to natural coagulant or chemical coagulant treatment alone. The impact of applying fibrous thin film on the coagulation activity was assessed in this study. In this study, a new chemical coagulant called Ecogent F-Loc was introduced. It can increase 40% of fluoride removal when combined with sodium aluminate. Combined chemical and natural coagulants gave the highest fluoride reduction using the Moringa Oleifera seed and eggshell with dosage of 100 ppm were 57% and 73%, respectively. When the chemical coagulant added with Moringa Oleifera seed, the fluoride removal efficiency increased from 50% to 77%. This showed that the combined chemical and natural coagulant showed similar coagulation effect as conventional chemical coagulant. In term of fibrous thin film, there is no significant effect on the coagulation activity of coagulant, but it helped to reduce the turbidity and coagulant residue in the synthetic wastewater and used to produce ionic solution for fluoride removal. In addition, the direct contact between particles and the impeller of Jar Test equipment can destroy the surface morphology of coagulant particles. With the support of the fibrous thin film, this challenge can be solved. In conclusion, the combined natural and chemical coagulant solutions can be used to substitute existing chemical treatment in fluoride wastewater treatment.
V L Chee; Chien Hwa Chong; C M Choo; Thomas S Y Choong. Combined natural and chemical coagulants to remove fluoride from wastewater. IOP Conference Series: Materials Science and Engineering 2020, 778, 1 .
AMA StyleV L Chee, Chien Hwa Chong, C M Choo, Thomas S Y Choong. Combined natural and chemical coagulants to remove fluoride from wastewater. IOP Conference Series: Materials Science and Engineering. 2020; 778 ():1.
Chicago/Turabian StyleV L Chee; Chien Hwa Chong; C M Choo; Thomas S Y Choong. 2020. "Combined natural and chemical coagulants to remove fluoride from wastewater." IOP Conference Series: Materials Science and Engineering 778, no. : 1.
A critical review on drying of low rank coal drying using conventional air-drying, fluidised bed drying and microwave drying methods. The parameters of different drying methods that affected the water effective diffusivity values were identified and critically discussed in details including hot air temperatures, flow rates, particle sizes, particle weights, and microwave powers. The microwave and fluidised bed drying methods are more effective in drying of low rank coal compared to the conventional hot air drying method. This is because the microwave drying method can heat up the internal part of the coal, thus leads to a higher drying rate and effective diffusivity values whereas the fluidised bed causes an uniform distribution of heating medium to heat up the low rank coal and the fluidisation resulted in a better mixing performance and a higher heat and mass transfer compared to the conventional hot air drying. Moreover, Midilli-Kucuk model was the best and most commonly used drying model for drying of the low rank coal. In the fluidised bed drying, the Midilli-Kucuk was the best-fitted drying model to dry the low rank coal whereas Wang & Singh model was the best drying model in the fixed-bed drying for the coarse particle of low rank coal. The microwave drying kinetics can be modeled using either the Page Model or Midilli-Kucuk model. Further to this, it was found that few parameters that significantly affected the effective diffusivity of the low rank coal are increasing temperature and flow rates of the convective air-drying meanwhile increasing the particle size and particle weight results in a decrease in effective diffusivity value for the fluidized-bed drying.
Jasper J X Chan; Chien Hwa Chong. A critical review on microwave, fluidised-bed and convective air-drying of low rank coals: The water diffusivity on coals. IOP Conference Series: Materials Science and Engineering 2020, 778, 1 .
AMA StyleJasper J X Chan, Chien Hwa Chong. A critical review on microwave, fluidised-bed and convective air-drying of low rank coals: The water diffusivity on coals. IOP Conference Series: Materials Science and Engineering. 2020; 778 ():1.
Chicago/Turabian StyleJasper J X Chan; Chien Hwa Chong. 2020. "A critical review on microwave, fluidised-bed and convective air-drying of low rank coals: The water diffusivity on coals." IOP Conference Series: Materials Science and Engineering 778, no. : 1.
This study aims to reduce the amount of specific energy consumed during the drying of fresh Murraya koenigii leaves by comparing four drying methods: (1) convective hot-air drying (CD; 40, 50 and 60 °C); (2) single-stage microwave-vacuum drying (MVD; 6, 9 and 12 W/g); (3) two-stage convective hot-air pre-drying followed by microwave-vacuum finishing–drying (CPD-MVFD; 50 °C, 9 W/g); and (4) freeze-drying as a control in the analysis sections. The drying kinetics were also modelled using thin-layer models. The quality parameters of dried M. koenigii leaves were measured including total polyphenolic content (TPC), antioxidant capacity (ABTS and FRAP), profiling of volatile compounds, colour analysis and water activity analysis. Results showed that CPD-MVFD effectively reduced the specific energy consumption of CD at 50 °C by 67.3% in terms of kilojoules per gram of fresh weight and 48.9% in terms of kilojoules per gram of water. The modified Page model demonstrated excellent fitting to the empirical data obtained. FD showed promising antioxidant activity. The major contributor of antioxidant capacity was TPC. The volatile compounds profiled by gas chromatography-mass spectrometry, namely, β-phellandrene (31%), α-pinene (19.9%), and sabinene (16%) were identified as the major compounds of dried M. koenigii leaves. Colour analysis showed MVD’s high performance in preserving the colour parameters of M. koenigii leaves under all conditions. The colour parameters were correlated to the antioxidant capacity and TPC. Water activity analysis showed that the water activity of M. koenigii leaves for all drying methods indicating that the conditions were microbiologically and shelf-stable. Pearson correlation showed the colour parameters of the leaves had a strong correlation to TPC. Overall, MVD showed promising energy consumption reduction and recovery in TPC and volatile compounds.
Choong Oon Choo; Bee Lin Chua; Adam Figiel; Klaudiusz Jałoszyński; Aneta Wojdyło; Antoni Szumny; Jacek Łyczko; Chien Hwa Chong. Hybrid Drying of Murraya koenigii Leaves: Energy Consumption, Antioxidant Capacity, Profiling of Volatile Compounds and Quality Studies. Processes 2020, 8, 240 .
AMA StyleChoong Oon Choo, Bee Lin Chua, Adam Figiel, Klaudiusz Jałoszyński, Aneta Wojdyło, Antoni Szumny, Jacek Łyczko, Chien Hwa Chong. Hybrid Drying of Murraya koenigii Leaves: Energy Consumption, Antioxidant Capacity, Profiling of Volatile Compounds and Quality Studies. Processes. 2020; 8 (2):240.
Chicago/Turabian StyleChoong Oon Choo; Bee Lin Chua; Adam Figiel; Klaudiusz Jałoszyński; Aneta Wojdyło; Antoni Szumny; Jacek Łyczko; Chien Hwa Chong. 2020. "Hybrid Drying of Murraya koenigii Leaves: Energy Consumption, Antioxidant Capacity, Profiling of Volatile Compounds and Quality Studies." Processes 8, no. 2: 240.
Malaysia’s oleochemical processing industry uses crude palm oil as the main source of process feedstocks. Physical–chemical treatment methods such as coagulation and flocculation processes are widely used to pre-treat oleochemical effluent followed by biological treatment to meet Standard A/B as required by the Department of Environment (DOE). Established chemicals that are used include aluminium sulphate and iron chloride as coagulants while the aluminium chloride, iron salts, and polyelectrolytes are used as flocculants. The industry is in constant effort to look into alternative chemicals that are friendly to both human and environment. Natural coagulants such as wheat germ and chitosan are proposed to treat the effluent. The investigations related to the removal rate of turbidity and chemical oxygen demand (COD) between natural and chemical coagulants were carried out. The effluent samples were analysed with the aluminium content. The results showed that the optimum dosage of wheat germ, chitosan, aluminium sulphate and iron chloride were: 2000, 20, 167 and 169 mg/L respectively. The turbidity reduction efficiency percentage using the wheat germ, chitosan, aluminium sulphate and iron chloride were reported at 80.2 ± 30.2, 78.8 ± 32.9, 96.2 ± 2.0 and 90.3 ± 3.9% respectively. The COD reduction efficiency by using wheat germ, chitosan, aluminium sulphate, and iron chloride were reported at 11.4 ± 5.8, 15.7 ± 6.6, 15.7 ± 3.1 and 15.9 ± 3.3% respectively. The findings showed that the effluent samples from natural coagulation process contains of lower aluminium concentration (0.1 ± 0.1 and 0.2 ± 0.1 mg/L) as compared to effluent samples from chemical coagulation process with the aluminium concentration of 2.4 ± 0.4 and 5.5 ± 0.3 mg/L. Thus, the use of wheat germ and chitosan are less hazardous to human health and environment.
Chee Ming Choo; Kiat Wei Tok; Fang Yenn Teo; Chien Hwa Chong; Vui Soon Chok; Mohd Fariz Majid. Use of Wheat Germ and Chitosan as the Natural Coagulant in Oleochemical Wastewater Treatment. Proceedings of EECE 2020 2019, 785 -797.
AMA StyleChee Ming Choo, Kiat Wei Tok, Fang Yenn Teo, Chien Hwa Chong, Vui Soon Chok, Mohd Fariz Majid. Use of Wheat Germ and Chitosan as the Natural Coagulant in Oleochemical Wastewater Treatment. Proceedings of EECE 2020. 2019; ():785-797.
Chicago/Turabian StyleChee Ming Choo; Kiat Wei Tok; Fang Yenn Teo; Chien Hwa Chong; Vui Soon Chok; Mohd Fariz Majid. 2019. "Use of Wheat Germ and Chitosan as the Natural Coagulant in Oleochemical Wastewater Treatment." Proceedings of EECE 2020 , no. : 785-797.
Chien Hwa Chong; Chung Lim Law; Adam Figiel; Tommy Asni. Diffusivity in Drying of Porous Media. Heat and Mass Transfer in Drying of Porous Media 2019, 37 -54.
AMA StyleChien Hwa Chong, Chung Lim Law, Adam Figiel, Tommy Asni. Diffusivity in Drying of Porous Media. Heat and Mass Transfer in Drying of Porous Media. 2019; ():37-54.
Chicago/Turabian StyleChien Hwa Chong; Chung Lim Law; Adam Figiel; Tommy Asni. 2019. "Diffusivity in Drying of Porous Media." Heat and Mass Transfer in Drying of Porous Media , no. : 37-54.
The preservation of active constituents in Cassia alata through the removal of moisture is crucial in producing a final product with high antioxidant activity. This study aims to determine the influences of various drying methods and drying conditions on the antioxidant activity, volatiles and phytosterols content of C. alata. The drying methods used were convective drying (CD) at 40 °C, 50 °C and 60 °C; freeze drying; vacuum microwave drying (VMD) at 6, 9 and 12 W/g; and two-stage convective pre-drying followed by vacuum microwave finish drying (CPD-VMFD) at 50 °C and 9 W/g. The drying kinetics of C. alata are best described by the thin-layer model (modified Page model). The highest antioxidant activity, TPC and volatile concentration were achieved with CD at 40 °C. GC-MS analysis identified the presence of 51 volatiles, which were mostly present in all samples but with quantitative variation. The dominant volatiles in fresh C. alata are 2-hexenal (60.28 mg 100 g-1 db), 1-hexanol (18.70 mg 100 g-1 db) and salicylic acid (15.05 mg 100 g-1 db). The concentration of phytosterols in fresh sample was 3647.48 mg 100 g-1 db, and the major phytosterols present in fresh and dried samples were β-sitosterol (1162.24 mg 100 g-1 db). CPD-VMFD was effective in ensuring the preservation of higher phytosterol content in comparison with CD at 50 °C. The final recommendation of a suitable drying method to dehydrate C. alata leaves is CD at 40 °C.
Chua; Adam Figiel; Chien Hwa Chong; Aneta Wojdyło; Antoni Szumny; Krzysztof Lech; Lech; Lisa Yen Wen Chua; Bee Lin Chua. Characterisation of the Convective Hot-Air Drying and Vacuum Microwave Drying of Cassia alata: Antioxidant Activity, Essential Oil Volatile Composition and Quality Studies. Molecules 2019, 24, 1625 .
AMA StyleChua, Adam Figiel, Chien Hwa Chong, Aneta Wojdyło, Antoni Szumny, Krzysztof Lech, Lech, Lisa Yen Wen Chua, Bee Lin Chua. Characterisation of the Convective Hot-Air Drying and Vacuum Microwave Drying of Cassia alata: Antioxidant Activity, Essential Oil Volatile Composition and Quality Studies. Molecules. 2019; 24 (8):1625.
Chicago/Turabian StyleChua; Adam Figiel; Chien Hwa Chong; Aneta Wojdyło; Antoni Szumny; Krzysztof Lech; Lech; Lisa Yen Wen Chua; Bee Lin Chua. 2019. "Characterisation of the Convective Hot-Air Drying and Vacuum Microwave Drying of Cassia alata: Antioxidant Activity, Essential Oil Volatile Composition and Quality Studies." Molecules 24, no. 8: 1625.
Drying is an important process in the preservation of antioxidants in medicinal plants. In this study, leaves of Phyla nodiflora, or commonly known as frog fruit, were dried using convective drying (CD) at 40, 50, and 60 °C; vacuum-microwave drying (VMD) at 6, 9, and 12 W/g; and convective pre-drying followed by vacuum-microwave finish drying (CPD–VMFD) at 50 °C and 9 W/g. Drying kinetics of P. nodiflora leaves was modelled, and the influences of drying methods on the antioxidant activity, total phenolic content, volatile and phytosterol contents, energy consumption, water activity, and color properties were determined. Results showed that drying kinetics was best described by modified Page model. VMD achieved highest drying rate, whereas VMFD considerably reduced the drying time of CD from 240 min to 105 min. CPD–VMFD was the best option to dry P. nodiflora in terms of retaining volatiles and phytosterols, with lower energy consumption than CD. Meanwhile, VMD at 6 W/g produced samples with the highest antioxidant activity with 2,2′-Azinobis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and ferric reducing antioxidant power (FRAP) value of 11.00 and 15.99 µM Trolox/100 g dw, respectively.
Lisa Yen Wen Chua; Bee Lin Chua; Adam Figiel; Chien Hwa Chong; Aneta Wojdyło; Antoni Szumny; Jacek Łyczko. Drying of Phyla nodiflora Leaves: Antioxidant Activity, Volatile and Phytosterol Content, Energy Consumption, and Quality Studies. Processes 2019, 7, 210 .
AMA StyleLisa Yen Wen Chua, Bee Lin Chua, Adam Figiel, Chien Hwa Chong, Aneta Wojdyło, Antoni Szumny, Jacek Łyczko. Drying of Phyla nodiflora Leaves: Antioxidant Activity, Volatile and Phytosterol Content, Energy Consumption, and Quality Studies. Processes. 2019; 7 (4):210.
Chicago/Turabian StyleLisa Yen Wen Chua; Bee Lin Chua; Adam Figiel; Chien Hwa Chong; Aneta Wojdyło; Antoni Szumny; Jacek Łyczko. 2019. "Drying of Phyla nodiflora Leaves: Antioxidant Activity, Volatile and Phytosterol Content, Energy Consumption, and Quality Studies." Processes 7, no. 4: 210.
The preservation of active constituents in fresh herbs is affected by drying methods. An effective drying method for Strobilanthes crispus which is increasingly marketed as an important herbal tea remains to be reported. This study evaluated the effects of conventional and new drying technologies, namely vacuum microwave drying methods, on the antioxidant activity and yield of essential oil volatiles and phytosterols. These drying methods included convective drying (CD) at 40 °C, 50 °C, and 60 °C; vacuum microwave drying (VMD) at 6, 9, and 12 W/g; convective pre-drying and vacuum microwave finish drying (CPD-VMFD) at 50 °C and 9 W/g; and freeze-drying (FD). GC–MS revealed 33 volatiles, and 2-hexen-1-ol, 2-hexenal, 1-octen-3-ol, linalool, and benzaldehyde were major constituents. The compounds β-sitosterol and α-linolenic acid were the most abundant phytosterol and fatty acid, respectively, in fresh S. crispus. The highest phenolic content was achieved with CD at 60 °C. The highest antioxidant activity was obtained with CD at 40 °C and VMD at 9 W/g. On the contrary, the highest total volatiles and phytosterols were detected with CD at 50 °C and VMD at 9 W/g, respectively. This study showed that CD and VMD were effective in producing highly bioactive S. crispus. A suitable drying parameter level, irrespective of the drying method used, was an important influencing factor.
Lisa Yen Wen Chua; Adam Figiel; Chien Hwa Chong; Aneta Wojdyło; Antoni Szumny; Thomas Shean Yaw Choong. Antioxidant Activity, and Volatile and Phytosterol Contents of Strobilanthes crispus Dehydrated Using Conventional and Vacuum Microwave Drying Methods. Molecules 2019, 24, 1397 .
AMA StyleLisa Yen Wen Chua, Adam Figiel, Chien Hwa Chong, Aneta Wojdyło, Antoni Szumny, Thomas Shean Yaw Choong. Antioxidant Activity, and Volatile and Phytosterol Contents of Strobilanthes crispus Dehydrated Using Conventional and Vacuum Microwave Drying Methods. Molecules. 2019; 24 (7):1397.
Chicago/Turabian StyleLisa Yen Wen Chua; Adam Figiel; Chien Hwa Chong; Aneta Wojdyło; Antoni Szumny; Thomas Shean Yaw Choong. 2019. "Antioxidant Activity, and Volatile and Phytosterol Contents of Strobilanthes crispus Dehydrated Using Conventional and Vacuum Microwave Drying Methods." Molecules 24, no. 7: 1397.
Drying is considered as the most common and fundamental technique for the postharvest preservation of herbs and is regarded as a good process to retain bioactive compounds. Past studies suggest that the choice of drying method and the parameters applied were able to influence the chemical and biological activities of herbs because pronounced differences in chemical content and composition were observed between the different drying methods. This has warranted numerous studies over the years to determine the influence of various drying methods on the content of bioactive compounds in functional food. However, reviews on the impact of drying on the bioactivity of dried herbs are rather scarce. Additionally, the influence of drying methods on the antibacterial activity of herbs has yet to be reviewed. Therefore, this paper attempts to provide a critical review on the influence of current drying process technology on the antibacterial and antioxidant properties, as well as the essential oil content, of various herbs. The use of innovative, new or existing drying technologies in preserving the active compounds was included in this paper. It was found that (i) no single drying method can be effectively used for the dehydration of all herbs; (ii) heat treatment can lead to biochemical changes (Maillard reaction), which increases the antibacterial activity; and (iii) innovative combined drying methods are promising in the production of herbs with high antioxidant activity and higher yields of total volatile concentrations.
Lisa Y. W. Chua; Chien Hwa Chong; Bee Lin Chua; Adam Figiel. Influence of Drying Methods on the Antibacterial, Antioxidant and Essential Oil Volatile Composition of Herbs: a Review. Food and Bioprocess Technology 2019, 12, 450 -476.
AMA StyleLisa Y. W. Chua, Chien Hwa Chong, Bee Lin Chua, Adam Figiel. Influence of Drying Methods on the Antibacterial, Antioxidant and Essential Oil Volatile Composition of Herbs: a Review. Food and Bioprocess Technology. 2019; 12 (3):450-476.
Chicago/Turabian StyleLisa Y. W. Chua; Chien Hwa Chong; Bee Lin Chua; Adam Figiel. 2019. "Influence of Drying Methods on the Antibacterial, Antioxidant and Essential Oil Volatile Composition of Herbs: a Review." Food and Bioprocess Technology 12, no. 3: 450-476.
The coagulation activity of Moringa oleifera seed and Hibiscus esculentus (okra) mucilage were assessed for their ability to remove both anionic and cationic contaminants in aluminium sulphate and hydrofluoric acid synthetic wastewater. The effect of encasing these coagulants in a fibrous thin film along with their effect on pH and concentration were also assessed. Assessment using the jar test showed a 79.9% aluminium reduction and 91.7% fluoride reduction using okra mucilage and Moringa oleifera, respectively. Besides that, there was no effect on both the pH and coagulation activity in the application of fibrous thin film. The plant-based coagulation activity is comparable with conventional coagulant as fluoride removal treated by polyaluminium chloride formulation was 85.3 ± 0.8% with the optimum dosage of 3 g/L. The significance of these findings in the application of fibrous thin film with plant-based coagulants could be an advantage for industries to commercialise mechanically prepared coagulants, which has a much longer shelf life as compared to chemically prepared coagulants, as it has the potential to reduce the turbidity associated with mechanically prepared coagulants. Also, these results indicate the possibility of having a cost-effective yet environmentally friendly water treatment solution that combines the application of both plant-based and conventional coagulants.
Winston Lik Khai Lim; Edwin Chin Yau Chung; Chien Hwa Chong; Nicholas Tze Kai Ong; Wee Seong Hew; Nurasatifah Binti Kahar; Zhen Jie Goh. Removal of fluoride and aluminium using plant-based coagulants wrapped with fibrous thin film. Process Safety and Environmental Protection 2018, 117, 704 -710.
AMA StyleWinston Lik Khai Lim, Edwin Chin Yau Chung, Chien Hwa Chong, Nicholas Tze Kai Ong, Wee Seong Hew, Nurasatifah Binti Kahar, Zhen Jie Goh. Removal of fluoride and aluminium using plant-based coagulants wrapped with fibrous thin film. Process Safety and Environmental Protection. 2018; 117 ():704-710.
Chicago/Turabian StyleWinston Lik Khai Lim; Edwin Chin Yau Chung; Chien Hwa Chong; Nicholas Tze Kai Ong; Wee Seong Hew; Nurasatifah Binti Kahar; Zhen Jie Goh. 2018. "Removal of fluoride and aluminium using plant-based coagulants wrapped with fibrous thin film." Process Safety and Environmental Protection 117, no. : 704-710.
Present study investigated the extraction kinetics of antioxidants from Piper betle by ultrasound-assisted extraction for three extraction variables: temperature, solute to solvent ratio and ethanol concentration. Based on the results of yield, total phenolic content and antioxidant activity, the optimum results were obtained at 50°C, 1:20 g/mL and 80% ethanol, respectively. Statistical coefficients of R2 ≥ 0.961 and RMSE ≤ 0.508 for two-site kinetic model confirm the use of proposed models for simulation and prediction purpose. Comparison with ascorbic acid and butylated hydroxytoluene solidifies the use of Piper betle as feasible source of natural antioxidants. The presence of hydroxychavicol and eugenol was affirmed by high-performance liquid chromatography assay.
Ameena Ali; Xiao Yien Lim; Chien Hwa Chong; Siau Hui Mah; Bee Lin Chua. Ultrasound-assisted extraction of natural antioxidants from betel leaves (Piper betle): Extraction kinetics and modeling. Separation Science and Technology 2018, 53, 2192 -2205.
AMA StyleAmeena Ali, Xiao Yien Lim, Chien Hwa Chong, Siau Hui Mah, Bee Lin Chua. Ultrasound-assisted extraction of natural antioxidants from betel leaves (Piper betle): Extraction kinetics and modeling. Separation Science and Technology. 2018; 53 (14):2192-2205.
Chicago/Turabian StyleAmeena Ali; Xiao Yien Lim; Chien Hwa Chong; Siau Hui Mah; Bee Lin Chua. 2018. "Ultrasound-assisted extraction of natural antioxidants from betel leaves (Piper betle): Extraction kinetics and modeling." Separation Science and Technology 53, no. 14: 2192-2205.
Ameena Ali; Xiao Yien Lim; Chien Hwa Chong; Siau Hui Mah; Bee Lin Chua. Optimization of ultrasound-assisted extraction of natural antioxidants from Piper betle using response surface methodology. LWT - Food Science and Technology 2018, 89, 681 -688.
AMA StyleAmeena Ali, Xiao Yien Lim, Chien Hwa Chong, Siau Hui Mah, Bee Lin Chua. Optimization of ultrasound-assisted extraction of natural antioxidants from Piper betle using response surface methodology. LWT - Food Science and Technology. 2018; 89 ():681-688.
Chicago/Turabian StyleAmeena Ali; Xiao Yien Lim; Chien Hwa Chong; Siau Hui Mah; Bee Lin Chua. 2018. "Optimization of ultrasound-assisted extraction of natural antioxidants from Piper betle using response surface methodology." LWT - Food Science and Technology 89, no. : 681-688.
The phenolic constituents in Piper betle are well known for their antioxidant potential; however, current literature has very little information on their stability under the influence of storage factors. Present study evaluated the stability of total phenolic content (TPC) and antioxidant activity together with individual phenolic constituents (hydroxychavicol, eugenol, isoeugenol and allylpyrocatechol 3,4-diacetate) present in dried Piper betle’s extract under different storage temperature of 5 and 25 °C with and without light for a period of six months. Both light and temperature significantly influenced TPC and its corresponding antioxidant activity over time. More than 95% TPC and antioxidant activity was retained at 5 °C in dark condition after 180 days of storage. Hydroxychavicol demonstrated the best stability with no degradation while eugenol and isoeugenol displayed moderate stability in low temperature (5 °C) and dark conditions. 4-allyl-1,2-diacetoxybenzene was the only compound that underwent complete degradation. A new compound, 2,4-di-tert-butylphenol, was detected after five weeks of storage only in the extracts exposed to light. Both zero-order and first-order kinetic models were adopted to describe the degradation kinetics of the extract’s antioxidant activity. Zero-order displayed better fit with higher correlation coefficients (R2 = 0.9046) and the half-life was determined as 62 days for the optimised storage conditions (5 °C in dark conditions).
Ameena Ali; Chien Hwa Chong; Siau Hui Mah; Luqman Chuah Abdullah; Thomas Shean Yaw Choong; Bee Lin Chua. Impact of Storage Conditions on the Stability of Predominant Phenolic Constituents and Antioxidant Activity of Dried Piper betle Extracts. Molecules 2018, 23, 484 .
AMA StyleAmeena Ali, Chien Hwa Chong, Siau Hui Mah, Luqman Chuah Abdullah, Thomas Shean Yaw Choong, Bee Lin Chua. Impact of Storage Conditions on the Stability of Predominant Phenolic Constituents and Antioxidant Activity of Dried Piper betle Extracts. Molecules. 2018; 23 (2):484.
Chicago/Turabian StyleAmeena Ali; Chien Hwa Chong; Siau Hui Mah; Luqman Chuah Abdullah; Thomas Shean Yaw Choong; Bee Lin Chua. 2018. "Impact of Storage Conditions on the Stability of Predominant Phenolic Constituents and Antioxidant Activity of Dried Piper betle Extracts." Molecules 23, no. 2: 484.
Thaothy NguyenHuynh; Rajesh Nithyanandam; Chien Hwa Chong; Duduku Krishnaiah. Configuration modification of a submerged membrane reactor for enzymatic hydrolysis of cellulose. Biocatalysis and Agricultural Biotechnology 2017, 12, 50 -58.
AMA StyleThaothy NguyenHuynh, Rajesh Nithyanandam, Chien Hwa Chong, Duduku Krishnaiah. Configuration modification of a submerged membrane reactor for enzymatic hydrolysis of cellulose. Biocatalysis and Agricultural Biotechnology. 2017; 12 ():50-58.
Chicago/Turabian StyleThaothy NguyenHuynh; Rajesh Nithyanandam; Chien Hwa Chong; Duduku Krishnaiah. 2017. "Configuration modification of a submerged membrane reactor for enzymatic hydrolysis of cellulose." Biocatalysis and Agricultural Biotechnology 12, no. : 50-58.
The conceive – design – implement – operate educational framework is implemented by educators to generate graduates who are able to tackle complex engineering challenges. A set of 12 standards define this framework and how to implement it. Taylor’s School of Engineering has been part of this framework for the past six years and utilises it in the design of its engineering curriculum. This paper shares the Taylor’s experience in adopting the framework by explaining the aforementioned underlying standards. The article guides the reader to evaluate the compliance to each standard, and the corresponding success in implementation.
Satesh Namasivayam; Mohammad Hosseini Fouladi; Chien Hwa Chong. A case study on the implementation of the conceive – design – implement – operate framework. International Journal of Mechanical Engineering Education 2016, 45, 28 -46.
AMA StyleSatesh Namasivayam, Mohammad Hosseini Fouladi, Chien Hwa Chong. A case study on the implementation of the conceive – design – implement – operate framework. International Journal of Mechanical Engineering Education. 2016; 45 (1):28-46.
Chicago/Turabian StyleSatesh Namasivayam; Mohammad Hosseini Fouladi; Chien Hwa Chong. 2016. "A case study on the implementation of the conceive – design – implement – operate framework." International Journal of Mechanical Engineering Education 45, no. 1: 28-46.
The objective of this study was to improve product quality of dehydrated fruits (apple, pear, papaya, mango) using combined drying techniques. This involved investigation of bioactivity, colour, and sensory assessment on colour of the dried products as well as the retention of the bio-active ingredients. The attributes of quality were compared in regard to the quality of dehydrated samples obtained from continuous heat pump (HP) drying technique. It was found that for apple, pear and mango the total colour change (ΔE) of samples dried using continuous heat pump (HP) or heat pump vacuum-microwave (HP/VM) methods was lower than of samples dried by other combined methods. However, for papaya, the lowest colour change exhibited by samples dried using hot air–cold air (HHC) method and the highest colour change was found for heat pump (HP) dehydrated samples. Sensory evaluation revealed that dehydrated pear with higher total colour change (ΔE) is more desirable because of its golden yellow appearance. In most cases the highest phenol content was found from fruits dried by HP/VM method. Judging from the quality findings on two important areas namely colour and bioactivity, it was found that combined drying method consisted of HP pre-drying followed by VM finish drying gave the best results for most dehydrated fruits studied in this work as the fruits contain first group of polyphenol compounds, which preferably requires low temperature followed by rapid drying strategy.
Chien Hwa Chong; Chung Lim Law; Adam Figiel; Aneta Wojdyło; Maciej Oziembłowski. Colour, phenolic content and antioxidant capacity of some fruits dehydrated by a combination of different methods. Food Chemistry 2013, 141, 3889 -3896.
AMA StyleChien Hwa Chong, Chung Lim Law, Adam Figiel, Aneta Wojdyło, Maciej Oziembłowski. Colour, phenolic content and antioxidant capacity of some fruits dehydrated by a combination of different methods. Food Chemistry. 2013; 141 (4):3889-3896.
Chicago/Turabian StyleChien Hwa Chong; Chung Lim Law; Adam Figiel; Aneta Wojdyło; Maciej Oziembłowski. 2013. "Colour, phenolic content and antioxidant capacity of some fruits dehydrated by a combination of different methods." Food Chemistry 141, no. 4: 3889-3896.
Apple cubes of 15 mm were dried naturally without adding any chemical preservative using various drying methods namely intermittent hot air–dehumidified air drying with cyclic temperature profile and step-up temperature profile, heat-pump-assisted (HP) drying, convective vacuum-microwave (C/VM) drying, and heat pump vacuum-microwave (HP/VM) drying. The drying kinetics of apple samples dehydrated by different methods was divided into characteristic drying periods and fitted with empirical models, which gave high value of determination coefficient. The application of C/VM in drying of fruits gave the shortest drying time compared to other drying methods (about 50 % of the total drying time). The drying time was affected by effective diffusivity ranging from 3.522 × 10−8 to 1.431 × 10−6 m2/min depending on the drying technique used. It was found that combined drying which apply vacuum microwave (C/VM, HP/VM) gave the lowest values in hardness and chewiness. In addition, HP/VM drying gave the highest retained total polyphenol content, antioxidant activity, and the best appearance quality.
Chien Hwa Chong; Adam Figiel; Chung Lim Law; Aneta Wojdyło. Combined Drying of Apple Cubes by Using of Heat Pump, Vacuum-Microwave, and Intermittent Techniques. Food and Bioprocess Technology 2013, 7, 975 -989.
AMA StyleChien Hwa Chong, Adam Figiel, Chung Lim Law, Aneta Wojdyło. Combined Drying of Apple Cubes by Using of Heat Pump, Vacuum-Microwave, and Intermittent Techniques. Food and Bioprocess Technology. 2013; 7 (4):975-989.
Chicago/Turabian StyleChien Hwa Chong; Adam Figiel; Chung Lim Law; Aneta Wojdyło. 2013. "Combined Drying of Apple Cubes by Using of Heat Pump, Vacuum-Microwave, and Intermittent Techniques." Food and Bioprocess Technology 7, no. 4: 975-989.
Sun drying of ciku (Manilkara zapota) was carried out on different sample sizes to investigate the effects on drying kinetics. It was found that the maximum drying rates of sun-dried ciku decreased with larger product size. Three sunny days are needed to dry the ciku slabs to an average final moisture content of 0.2 g H2O/g dry mass. The results showed that hardness and chewiness of the dried samples were significantly different (p < 0.05) compared to fresh ciku slabs and commercial dried fruit. The color measurement of dried product showed that L∗ and b∗ values significantly decreased (p < 0.05), whereas the a∗ value increase was not significantly different (p > 0.05) compared to fresh ciku slabs. In addition, sun-dried ciku retained a total polyphenol content (TPC) that was relatively low (p < 0.05) compared to fresh ciku.
Chien Hwa Chong; Chung Lim Law; Michael Cloke; Luqman Chuah Abdullah; Wan Ramli Wan Daud. Drying Models and Quality Analysis of Sun-Dried Ciku. Drying Technology 2009, 27, 985 -992.
AMA StyleChien Hwa Chong, Chung Lim Law, Michael Cloke, Luqman Chuah Abdullah, Wan Ramli Wan Daud. Drying Models and Quality Analysis of Sun-Dried Ciku. Drying Technology. 2009; 27 (9):985-992.
Chicago/Turabian StyleChien Hwa Chong; Chung Lim Law; Michael Cloke; Luqman Chuah Abdullah; Wan Ramli Wan Daud. 2009. "Drying Models and Quality Analysis of Sun-Dried Ciku." Drying Technology 27, no. 9: 985-992.