Andrographis paniculata is a commonly used herb in traditional Chinese medicine for clearing heat,detoxifying,and treating colds.Modern pharmacological studies indicate that its primary active component,andrographolid...Andrographis paniculata is a commonly used herb in traditional Chinese medicine for clearing heat,detoxifying,and treating colds.Modern pharmacological studies indicate that its primary active component,andrographolide(AG),exhibits significant anti-inflammatory and anticancer activity.However,its poor water solubility and low oral bioavailability have limited its clinical application.This study first employed ultrasonicassisted extraction(UAE)to isolate AG from Andrographis paniculata,with its content quantified via colorimetric analysis.Subsequently,AG solid lipid nanoparticles(AG-SLNs)were prepared using a modified solvent injection method.The resulting nanoparticles exhibited an average particle size of 214.3±2.9 nm,a zeta potential of-23.57±1.4 mV,and a polydispersity index(PDI)of 0.24±0.014.In vitro release studies demonstrated controlled and prolonged release of AG compared to free AG.Cytotoxicity of AG and AG-SLNs against breast cancer cells was evaluated using MTT assay.The IC50 of AG-SLNs was 11.23μg/mL,significantly lower than that of free AG reference standard(14.31μg/mL)and the extract(18.68μg/mL).These results indicate that AG possesses anticancer properties,and nanoencapsulation enhances AG's antiproliferative effect on breast cancer cells while improving its bioactivity.展开更多
The significant amount of ash content in agricultural biomass presents an enormous challenge for efficient conversion processes.In addressing this issue,various deashing treatments have been tested and established,inc...The significant amount of ash content in agricultural biomass presents an enormous challenge for efficient conversion processes.In addressing this issue,various deashing treatments have been tested and established,including simple leaching techniques,which can either be performed with or without the addition of chemical agents.These techniques hold promise for improving the deashing efficiency while potentially altering the structural and chemical composition of biomass,specifically lignin content,which is the key focus of this review.This review starts by exploring the presence of ash in agricultural residues and its impact on biomass properties.Next,this review examines deashing strategies aimed at reducing ash levels in biomass followed by analysis of the resulting changes in lignin physical and chemical properties as well as its thermal characteristics.The final part of this review is concluded by the discussion on the limitations of current approaches and the possible future directions to address the challenges covering the environmental impacts of the deashing treatments.A green process approach is emphasized as a sustainable solution with the aim to minimize negative environmental impacts associated with chemical usage during deashing.Finally,this review highlights the potential for ash recovery as a byproduct of the deashing processes,paving the way for an integrative,closed-loop approach within the biorefinery concept.展开更多
Edible bird＇s nest （EBN） is currently widely consumed by the Chinese community as tonic food and functional food, which is believed to have many medicinal benefits. Some studies have reported the biochemical compos...Edible bird＇s nest （EBN） is currently widely consumed by the Chinese community as tonic food and functional food, which is believed to have many medicinal benefits. Some studies have reported the biochemical compositions of EBN, graded on the basis of colour, nitrate and nitrite contents. Other studies have shown significant biological effects, while ongoing research is in progress to explore potential pharmacological applications. The high demand for EBNs in the global market has forced the local regulatory bodies to monitor swiftlet farming activities, including the EBN cleaning process. Furthermore, numerous techniques have been developed to authenticate EBN; proteomics is likely to be the most promising of these methods. However, there are limited numbers of relevant protein sequences deposited at the database. More research is needed at the molecular level to explore the mechanisms behind the biological functions, such as bone strength improvement, skin rejuvenation, epidermal growth factor activity and cell proliferation.The current and future prospects of EBN and swiftlet farming are critically reviewed in this article.展开更多
The drying kinetics of Roselle （Hibiscus sabdariffa L） of variety Terengganu （UMKL-1） and the quality attribution of Roselle were studied. The experiments were conducted using four different drying methods, includ...The drying kinetics of Roselle （Hibiscus sabdariffa L） of variety Terengganu （UMKL-1） and the quality attribution of Roselle were studied. The experiments were conducted using four different drying methods, including solar greenhouse drying （SD）, solar greenhouse with intermittent heat pump drying （SIHP）, hot air drying （HA） and heat pump drying （HP）. Among the four drying methods, HP achieved the highest drying rate at a range from 0.054 g H20-（g DM）-1. rain-1 to 0.212 g H20-（g DM）-1. rain 1 while SD had the lowest drying rate, measured at 0.042 g H2O. （g DM） 1.min- 1. The analysis on colour kinetics revealed that there is no significant colour loss （p 〉 0.05） observed from HP＇s dried Roselle. Greater amount of flavonoid compounds i.e. protocatechuic acid was found in SD and SIHP dried finished product whereas HP＇s dried Roselle contains higher percentage of catechin as compared to other drying methods.展开更多
The physical properties, total phenols, total flavonoid content and free radical scavenging activities of honey samples from Malaysia were investigated. The physical properties of Tualang, Gelam and Acacia honey sampl...The physical properties, total phenols, total flavonoid content and free radical scavenging activities of honey samples from Malaysia were investigated. The physical properties of Tualang, Gelam and Acacia honey samples, in terms of pH, color, moisture, electrical conductivity and total soluble solid were significantly different (p = 0.000). Gelam honey was reported to have the highest total phenols (606.17 mg GAE/kg honey) and flavonoid content (183.43 mg RE/kg honey). Tualang honey was reported to have the highest free radical scavenging activity with the IC50, 72.75 g/L compared to Gelam (77.41 g/L) and Acacia (90.83 g/L). There is no significant difference has been revealed among honey samples for radical scavenging activity (p = 0.827). Nevertheless, strong correlation was obtained between pH, color, electrical conductivity and total soluble solid with the scavenging activity of all honey samples with the correlative coefficient, r = 0.979, 0.902, 0.917 and 0.957, respectively. The establishment of the statistical correlation could be useful for honey related industry.展开更多
Piper sarmentosum Roxb.(Piperaceae)is a traditional medicinal and food plant widely distributed in the tropical and subtropical regions of Asia,offering both health and culinary benefits.In this study the secondary me...Piper sarmentosum Roxb.(Piperaceae)is a traditional medicinal and food plant widely distributed in the tropical and subtropical regions of Asia,offering both health and culinary benefits.In this study the secondary metabolites in different organs of P.sarmentosum were identified and their relative abundances were characterized.The metabolic profiles of leaves,roots,stems and fruits were comprehensively investigated by liquid chromatography high-resolution mass spectrometry(LC-HR-MS)and the data subsequently analyzed using multivariate statistical methods.Manual interpretation of the tandem mass spectrometric(MS/MS)fragmentation patterns revealed the presence of 154 tentatively identified metabolites,mostly represented by alkaloids and flavonoids.Principle component analysis and hierarchical clustering indicated the predominant occurrence of flavonoids,lignans and phenyl propanoids in leaves,aporphines in stems,piperamides in fruits and lignan-amides in roots.Overall,this study provides extensive data on the metabolite composition of P.sarmentosum,supplying useful information for bioactive compounds discovery and patterns of their preferential biosynthesis or storage in specific organs.This can be used to optimize production and harvesting as well as to maximize the plant’s economic value as herbal medicine or in food applications.展开更多
Pueraria mirifica(PM)has traditionally been used to relieve postmenopausal symptoms.Recently,its extract has been developed into various cosmetic products to promote skin rejuvenation and youthfulness.This study inves...Pueraria mirifica(PM)has traditionally been used to relieve postmenopausal symptoms.Recently,its extract has been developed into various cosmetic products to promote skin rejuvenation and youthfulness.This study investigated the phytochemicals of PM tuber and compared between the tuber flesh and its outer peel.Puerarin which is one of the major isoflavones and being considered as the marker compound was used to determine the presence of PM extract in local cosmetic products.Puerarin could be ionized by a mass spectrometer at both negative and positive modes.The peak ionized at the negative mode showed to have a narrower peak width(0.2 min)and higher signal-to-noise ratio(30)for pueararin(1 mg/L).The results also found PM extract contained many C-and O-glycosylated isoflavones,especially from its peel extract.This explains the peel extract showed to have four times higher antiradical activity than those of flesh extract.Puerarin from the cosmetic products was recovered via successive methanolic sonication and followed by liquid-liquid extraction using ethyl acetate.Puerarin was successfully partitioned from the highly complex chemical mixture of cosmetic products with the recovery ranged from 89.1%to 115%.Hence,isoflavones was found to be higher at the outer peels than its tuber flesh.A simple and reliable method has been developed to analyse the presence of PM extract in cosmetic products based on the detection of puerarin after successive extraction via methanolic sonication and ethyl acetate partition.展开更多
在基于核磁共振(NMR)的代谢组学数据分析中,尺度缩放是关键的预处理步骤之一,其主要目的是通过调整数据的方差结构,改善后续的多变量统计分析的结果。从信息熵的角度出发,利用KullbackLeibler(K-L)散度来度量不同实验分组的生物样品的1 ...在基于核磁共振(NMR)的代谢组学数据分析中,尺度缩放是关键的预处理步骤之一,其主要目的是通过调整数据的方差结构,改善后续的多变量统计分析的结果。从信息熵的角度出发,利用KullbackLeibler(K-L)散度来度量不同实验分组的生物样品的1 H NMR波谱数据的差异程度,并结合单位方差缩放法,提出一种基于K-L散度的尺度缩放方法。该方法先利用单位方差法将数据各变量的标准差调整到同一水平上,再利用K-L散度对各变量进行有监督地加权,增强重要变量、减弱无关变量。由于K-L散度是在概率分布的意义上度量数据间的差异程度,且对于高斯和非高斯分布的数据均适用,因此能更准确地度量不同实验分组样品的1 H NMR波谱数据的差异性,从而更有效地地对谱数据的重要变量进行识别和加权。人群尿液1 H NMR波谱数据的分析结果表明,基于K-L散度的尺度缩放方法能有效抑制噪声变量,同时很好地区分特征变量和非特征变量;提高主成分回归(PCR)模型的判别能力;改善偏最小二乘回归判别分析(PLS-DA)模型的解释能力、预测能力以及对特征代谢物的辨识能力。展开更多
Nanopolystyrene was used as a solid support for the covalent immobilization of Candida antarctica lipase B(Cal B) using the photoreactive reagent 1‐fluoro‐2‐nitro‐4‐azido benzene(FNAB) as a cou‐pling reagent. Th...Nanopolystyrene was used as a solid support for the covalent immobilization of Candida antarctica lipase B(Cal B) using the photoreactive reagent 1‐fluoro‐2‐nitro‐4‐azido benzene(FNAB) as a cou‐pling reagent. The obtained derivative was then used as a biocatalyst in a microwave assisted ester‐ification experiment. Factors such as contact time, pH, and enzyme concentration were investigated during immobilization. The hydrolytic activity, thermal, and operational stability of immobi‐lized‐Cal B were determined. The maximum immobilized yield(218 μg/mg support) obtained at pH 6.8 exhibited optimum hydrolytic activity(4.42 × 103 mU p‐nitrophenol/min). The thermal stability of Cal B improved significantly when it was immobilized at pH 10, however, the immobilized yield was very low(93.6 μg/mg support). The immobilized‐Cal B prepared at pH 6.8 and pH 10 retained 50% of its initial activity after incubation periods of 14 and 16 h, respectively, at 60 °C. The opera‐tional stability was investigated for the microwave assisted esterification of oleic acid with metha‐nol. Immobilized‐Cal B retained 50% of its initial activity after 15 batch cycles in the micro‐wave‐assisted esterification. The esterification time was notably reduced under microwave irradia‐tion. The combined use of a biocatalyst and microwave heating is thus an alternative total green synthesis process.展开更多
Food agricultural waste from fruit products such as rinds can be one source of environmental pollution.Therefore,the study was conducted to investigate the total phenolic content,total flavonoid content,antioxidant pr...Food agricultural waste from fruit products such as rinds can be one source of environmental pollution.Therefore,the study was conducted to investigate the total phenolic content,total flavonoid content,antioxidant property,and chemical profiling using gas chromatography-mass spectrometer(GC-MS)and high-performance liquid chromatography tandem mass spectrometry of triple quadrupole(HP LCMS-MS QTOF).Ultrasoundassisted extraction for 45 min was used as a green technique to extract bioactive compounds from watermelon(Citrullus lanatus)and wintermelon(Benincasa hispida)rinds.The total phenolic content and total flavonoid content of ultrasound-assisted extraction were compared with maceration technique.As revealed by the results,maceration technique had a lower total phenolic content for both C.lanatus rind(7.07±0.86μg GAE/mg)and B.hispida rind(13.87±0.11μg GAE/mg)compared to ultrasound-assisted extraction.The similar trends can be observed in total flavonoid content of C.lanatus rind(4.97±0.29μg RE/g)and B.hispida rind(8.30±0.17μg RE/g)by maceration which showed a lower quantity compared to ultrasound-assisted extraction.The ultrasound-assisted extraction was selected for further analysis.The total phenolic content assay found that the B.hispida rind extract exhibited higher total phenolic content values(23.39±0.22μg GAE/mg),than C.lanatus rind extract(15.10±0.58μg GAE/mg).B.hispida rind extract had a higher total flavonoid content(11.17±0.17μg RE/g)than C.lanatus rind extract(6.16±0.09μg RE/g).The antioxidant activity was investigated using DPPH scavenging assay.The antioxidant capacity of B.hispida rind extract(20872.19±1301.47 mg/mL)stronger compared to C.lanatus rind extract(23514.47±678.70 mg/mL).Results revealed that there was a negative correlation between total phenolic content,total flavonoid content,and DPPH scavenging activity IC50.The phytoconstituent determination in B.hispida and C.lanatus rind extract showed both contained phenolic,malic acid,and other compounds that might have contributed to antioxidant activities.Phenolic,flavonoid,and antioxidant activities are useful to valorize B.hispida and C.lanatus rinds as they can be converted into new income-generating resources in agriculture and the food industry.展开更多
Enhancing awareness of personal cleanliness and antibacterial resistance has intensified the antibacterial substance request on consumable products. Antibacterial agents that have been commercialized nowadays are prod...Enhancing awareness of personal cleanliness and antibacterial resistance has intensified the antibacterial substance request on consumable products. Antibacterial agents that have been commercialized nowadays are produced from inorganic and non-renewable substances. This provides several drawbacks, particularly against health and environmental issues. Therefore, many scientists work on substituting fossil-fuel-based antibacterial agents with natural ones such as from biomass. Biomass derivatives, natural abundances of biopolymers in the world, amount to major compounds including polysaccharides (cellulose, hemicellulose, and chitosan) and polyphenol (tannin and lignin) substances which are capable to combat the growth of Gram-positive bacteria and Gram-negative bacteria. To date, no report focuses on a deep understanding of antibacterial properties derived from biomass and the internal and external factors effects. This work provides that gap because comprehensive knowledge is necessary before applying biomass to the products. The potency of biomass derivatives as antibacterial additives is also summarized. Basic knowledge of antibacterial characteristics to the application in products is highlighted in this review. Besides, the discussion about challenges and future perspectives is also delivered.展开更多
This study was focused on the preparation of water-soluble propolis extract as the natural preservative for perishable jaboticaba juice.A successive extraction and alkaline hydrolysis were performed to produce water-s...This study was focused on the preparation of water-soluble propolis extract as the natural preservative for perishable jaboticaba juice.A successive extraction and alkaline hydrolysis were performed to produce water-soluble propolis extract.The propolis extract was found to have a high content of phenolics and flavonoids,but a low concentration of wax.The hydrolysed propolis extract was added into jaboticaba juice and the treated juice quality was monitored for 2 weeks at 4℃.The results found that the performance of propolis extract was comparable with chemical preservative,sodium benzoate in similar amount(0.035%)used in the present study.The comparison was performed based on the physiochemical properties such as pH,titratable acidity,browning index and ascorbic acid content of juice.Ascorbic acid was the most reliable parameter to monitor the kinetic degradation of jaboticaba juice.Its degradation followed a first order kinetic model with a lower kinetic constant(0.1912 mg/mL/day)than that of non-treated juice(0.2073 mg/mL/day).The second reliable parameter was titratable acidity which could be used to monitor the rate of acid formation resulting from the breakdown of fruit sugars during degradation.The acidity of juice was slightly increased with storage time following zero order kinetics.The browning index was not suitable for juice quality monitoring as the addition of propolis would reduce flavylium cations of anthocyanins to be colourless.This non-thermal extraction followed by mild alkaline hydrolysis at pH 7.5 could produce good quality propolis extract,possibly as an alternative to chemical preservatives for jaboticaba juice.展开更多
文摘Andrographis paniculata is a commonly used herb in traditional Chinese medicine for clearing heat,detoxifying,and treating colds.Modern pharmacological studies indicate that its primary active component,andrographolide(AG),exhibits significant anti-inflammatory and anticancer activity.However,its poor water solubility and low oral bioavailability have limited its clinical application.This study first employed ultrasonicassisted extraction(UAE)to isolate AG from Andrographis paniculata,with its content quantified via colorimetric analysis.Subsequently,AG solid lipid nanoparticles(AG-SLNs)were prepared using a modified solvent injection method.The resulting nanoparticles exhibited an average particle size of 214.3±2.9 nm,a zeta potential of-23.57±1.4 mV,and a polydispersity index(PDI)of 0.24±0.014.In vitro release studies demonstrated controlled and prolonged release of AG compared to free AG.Cytotoxicity of AG and AG-SLNs against breast cancer cells was evaluated using MTT assay.The IC50 of AG-SLNs was 11.23μg/mL,significantly lower than that of free AG reference standard(14.31μg/mL)and the extract(18.68μg/mL).These results indicate that AG possesses anticancer properties,and nanoencapsulation enhances AG's antiproliferative effect on breast cancer cells while improving its bioactivity.
基金funded by the joint research collaboration of the Research Organization of Nanotechnology and Material,National Research and Innovation Agency(BRIN)(Grant number:8/HK/II/2024)with the title Organosolv Lignin-Based Hydrogels from Sugarcane Leaves and Their Potential as Wound Dressings with Widya Fatriasari as the Principal Investigatorthe Degree by Research(DBR)program of BRIN with scheme number:20/III.10/HK/2024 and scholarship number 4637/II.5.4/SI.06.01/7/2024 for Eko Budi Santoso。
文摘The significant amount of ash content in agricultural biomass presents an enormous challenge for efficient conversion processes.In addressing this issue,various deashing treatments have been tested and established,including simple leaching techniques,which can either be performed with or without the addition of chemical agents.These techniques hold promise for improving the deashing efficiency while potentially altering the structural and chemical composition of biomass,specifically lignin content,which is the key focus of this review.This review starts by exploring the presence of ash in agricultural residues and its impact on biomass properties.Next,this review examines deashing strategies aimed at reducing ash levels in biomass followed by analysis of the resulting changes in lignin physical and chemical properties as well as its thermal characteristics.The final part of this review is concluded by the discussion on the limitations of current approaches and the possible future directions to address the challenges covering the environmental impacts of the deashing treatments.A green process approach is emphasized as a sustainable solution with the aim to minimize negative environmental impacts associated with chemical usage during deashing.Finally,this review highlights the potential for ash recovery as a byproduct of the deashing processes,paving the way for an integrative,closed-loop approach within the biorefinery concept.
文摘Edible bird＇s nest （EBN） is currently widely consumed by the Chinese community as tonic food and functional food, which is believed to have many medicinal benefits. Some studies have reported the biochemical compositions of EBN, graded on the basis of colour, nitrate and nitrite contents. Other studies have shown significant biological effects, while ongoing research is in progress to explore potential pharmacological applications. The high demand for EBNs in the global market has forced the local regulatory bodies to monitor swiftlet farming activities, including the EBN cleaning process. Furthermore, numerous techniques have been developed to authenticate EBN; proteomics is likely to be the most promising of these methods. However, there are limited numbers of relevant protein sequences deposited at the database. More research is needed at the molecular level to explore the mechanisms behind the biological functions, such as bone strength improvement, skin rejuvenation, epidermal growth factor activity and cell proliferation.The current and future prospects of EBN and swiftlet farming are critically reviewed in this article.
基金Supported by the Ministry of Agriculture and Agro-Based Industry(MOA),Malaysia(NER30001)
文摘The drying kinetics of Roselle （Hibiscus sabdariffa L） of variety Terengganu （UMKL-1） and the quality attribution of Roselle were studied. The experiments were conducted using four different drying methods, including solar greenhouse drying （SD）, solar greenhouse with intermittent heat pump drying （SIHP）, hot air drying （HA） and heat pump drying （HP）. Among the four drying methods, HP achieved the highest drying rate at a range from 0.054 g H20-（g DM）-1. rain-1 to 0.212 g H20-（g DM）-1. rain 1 while SD had the lowest drying rate, measured at 0.042 g H2O. （g DM） 1.min- 1. The analysis on colour kinetics revealed that there is no significant colour loss （p 〉 0.05） observed from HP＇s dried Roselle. Greater amount of flavonoid compounds i.e. protocatechuic acid was found in SD and SIHP dried finished product whereas HP＇s dried Roselle contains higher percentage of catechin as compared to other drying methods.
文摘The physical properties, total phenols, total flavonoid content and free radical scavenging activities of honey samples from Malaysia were investigated. The physical properties of Tualang, Gelam and Acacia honey samples, in terms of pH, color, moisture, electrical conductivity and total soluble solid were significantly different (p = 0.000). Gelam honey was reported to have the highest total phenols (606.17 mg GAE/kg honey) and flavonoid content (183.43 mg RE/kg honey). Tualang honey was reported to have the highest free radical scavenging activity with the IC50, 72.75 g/L compared to Gelam (77.41 g/L) and Acacia (90.83 g/L). There is no significant difference has been revealed among honey samples for radical scavenging activity (p = 0.827). Nevertheless, strong correlation was obtained between pH, color, electrical conductivity and total soluble solid with the scavenging activity of all honey samples with the correlative coefficient, r = 0.979, 0.902, 0.917 and 0.957, respectively. The establishment of the statistical correlation could be useful for honey related industry.
基金supported by the German Academic Exchange Service(DAAD)as a grant scholarship and part of the Ph.D.thesis of IW.Funding program/-ID:Research Grants-Doctoral Programs in Germany,2017/18(57299294),ST34.
文摘Piper sarmentosum Roxb.(Piperaceae)is a traditional medicinal and food plant widely distributed in the tropical and subtropical regions of Asia,offering both health and culinary benefits.In this study the secondary metabolites in different organs of P.sarmentosum were identified and their relative abundances were characterized.The metabolic profiles of leaves,roots,stems and fruits were comprehensively investigated by liquid chromatography high-resolution mass spectrometry(LC-HR-MS)and the data subsequently analyzed using multivariate statistical methods.Manual interpretation of the tandem mass spectrometric(MS/MS)fragmentation patterns revealed the presence of 154 tentatively identified metabolites,mostly represented by alkaloids and flavonoids.Principle component analysis and hierarchical clustering indicated the predominant occurrence of flavonoids,lignans and phenyl propanoids in leaves,aporphines in stems,piperamides in fruits and lignan-amides in roots.Overall,this study provides extensive data on the metabolite composition of P.sarmentosum,supplying useful information for bioactive compounds discovery and patterns of their preferential biosynthesis or storage in specific organs.This can be used to optimize production and harvesting as well as to maximize the plant’s economic value as herbal medicine or in food applications.
文摘Pueraria mirifica(PM)has traditionally been used to relieve postmenopausal symptoms.Recently,its extract has been developed into various cosmetic products to promote skin rejuvenation and youthfulness.This study investigated the phytochemicals of PM tuber and compared between the tuber flesh and its outer peel.Puerarin which is one of the major isoflavones and being considered as the marker compound was used to determine the presence of PM extract in local cosmetic products.Puerarin could be ionized by a mass spectrometer at both negative and positive modes.The peak ionized at the negative mode showed to have a narrower peak width(0.2 min)and higher signal-to-noise ratio(30)for pueararin(1 mg/L).The results also found PM extract contained many C-and O-glycosylated isoflavones,especially from its peel extract.This explains the peel extract showed to have four times higher antiradical activity than those of flesh extract.Puerarin from the cosmetic products was recovered via successive methanolic sonication and followed by liquid-liquid extraction using ethyl acetate.Puerarin was successfully partitioned from the highly complex chemical mixture of cosmetic products with the recovery ranged from 89.1%to 115%.Hence,isoflavones was found to be higher at the outer peels than its tuber flesh.A simple and reliable method has been developed to analyse the presence of PM extract in cosmetic products based on the detection of puerarin after successive extraction via methanolic sonication and ethyl acetate partition.
文摘在基于核磁共振(NMR)的代谢组学数据分析中,尺度缩放是关键的预处理步骤之一,其主要目的是通过调整数据的方差结构,改善后续的多变量统计分析的结果。从信息熵的角度出发,利用KullbackLeibler(K-L)散度来度量不同实验分组的生物样品的1 H NMR波谱数据的差异程度,并结合单位方差缩放法,提出一种基于K-L散度的尺度缩放方法。该方法先利用单位方差法将数据各变量的标准差调整到同一水平上,再利用K-L散度对各变量进行有监督地加权,增强重要变量、减弱无关变量。由于K-L散度是在概率分布的意义上度量数据间的差异程度,且对于高斯和非高斯分布的数据均适用,因此能更准确地度量不同实验分组样品的1 H NMR波谱数据的差异性,从而更有效地地对谱数据的重要变量进行识别和加权。人群尿液1 H NMR波谱数据的分析结果表明,基于K-L散度的尺度缩放方法能有效抑制噪声变量,同时很好地区分特征变量和非特征变量;提高主成分回归(PCR)模型的判别能力;改善偏最小二乘回归判别分析(PLS-DA)模型的解释能力、预测能力以及对特征代谢物的辨识能力。
基金support by the Ministry of Higher Education (MOHE) Malaysia, Ministry ofAgricultural (MOA) and University Teknology Malayisa
文摘Nanopolystyrene was used as a solid support for the covalent immobilization of Candida antarctica lipase B(Cal B) using the photoreactive reagent 1‐fluoro‐2‐nitro‐4‐azido benzene(FNAB) as a cou‐pling reagent. The obtained derivative was then used as a biocatalyst in a microwave assisted ester‐ification experiment. Factors such as contact time, pH, and enzyme concentration were investigated during immobilization. The hydrolytic activity, thermal, and operational stability of immobi‐lized‐Cal B were determined. The maximum immobilized yield(218 μg/mg support) obtained at pH 6.8 exhibited optimum hydrolytic activity(4.42 × 103 mU p‐nitrophenol/min). The thermal stability of Cal B improved significantly when it was immobilized at pH 10, however, the immobilized yield was very low(93.6 μg/mg support). The immobilized‐Cal B prepared at pH 6.8 and pH 10 retained 50% of its initial activity after incubation periods of 14 and 16 h, respectively, at 60 °C. The opera‐tional stability was investigated for the microwave assisted esterification of oleic acid with metha‐nol. Immobilized‐Cal B retained 50% of its initial activity after 15 batch cycles in the micro‐wave‐assisted esterification. The esterification time was notably reduced under microwave irradia‐tion. The combined use of a biocatalyst and microwave heating is thus an alternative total green synthesis process.
文摘Food agricultural waste from fruit products such as rinds can be one source of environmental pollution.Therefore,the study was conducted to investigate the total phenolic content,total flavonoid content,antioxidant property,and chemical profiling using gas chromatography-mass spectrometer(GC-MS)and high-performance liquid chromatography tandem mass spectrometry of triple quadrupole(HP LCMS-MS QTOF).Ultrasoundassisted extraction for 45 min was used as a green technique to extract bioactive compounds from watermelon(Citrullus lanatus)and wintermelon(Benincasa hispida)rinds.The total phenolic content and total flavonoid content of ultrasound-assisted extraction were compared with maceration technique.As revealed by the results,maceration technique had a lower total phenolic content for both C.lanatus rind(7.07±0.86μg GAE/mg)and B.hispida rind(13.87±0.11μg GAE/mg)compared to ultrasound-assisted extraction.The similar trends can be observed in total flavonoid content of C.lanatus rind(4.97±0.29μg RE/g)and B.hispida rind(8.30±0.17μg RE/g)by maceration which showed a lower quantity compared to ultrasound-assisted extraction.The ultrasound-assisted extraction was selected for further analysis.The total phenolic content assay found that the B.hispida rind extract exhibited higher total phenolic content values(23.39±0.22μg GAE/mg),than C.lanatus rind extract(15.10±0.58μg GAE/mg).B.hispida rind extract had a higher total flavonoid content(11.17±0.17μg RE/g)than C.lanatus rind extract(6.16±0.09μg RE/g).The antioxidant activity was investigated using DPPH scavenging assay.The antioxidant capacity of B.hispida rind extract(20872.19±1301.47 mg/mL)stronger compared to C.lanatus rind extract(23514.47±678.70 mg/mL).Results revealed that there was a negative correlation between total phenolic content,total flavonoid content,and DPPH scavenging activity IC50.The phytoconstituent determination in B.hispida and C.lanatus rind extract showed both contained phenolic,malic acid,and other compounds that might have contributed to antioxidant activities.Phenolic,flavonoid,and antioxidant activities are useful to valorize B.hispida and C.lanatus rinds as they can be converted into new income-generating resources in agriculture and the food industry.
基金Besides,thanks for financing assistance(No.SKPB6412/LPDP/LPDP.3/2023)from the Indonesia Endowment Fund for Education(LPDP).
文摘Enhancing awareness of personal cleanliness and antibacterial resistance has intensified the antibacterial substance request on consumable products. Antibacterial agents that have been commercialized nowadays are produced from inorganic and non-renewable substances. This provides several drawbacks, particularly against health and environmental issues. Therefore, many scientists work on substituting fossil-fuel-based antibacterial agents with natural ones such as from biomass. Biomass derivatives, natural abundances of biopolymers in the world, amount to major compounds including polysaccharides (cellulose, hemicellulose, and chitosan) and polyphenol (tannin and lignin) substances which are capable to combat the growth of Gram-positive bacteria and Gram-negative bacteria. To date, no report focuses on a deep understanding of antibacterial properties derived from biomass and the internal and external factors effects. This work provides that gap because comprehensive knowledge is necessary before applying biomass to the products. The potency of biomass derivatives as antibacterial additives is also summarized. Basic knowledge of antibacterial characteristics to the application in products is highlighted in this review. Besides, the discussion about challenges and future perspectives is also delivered.
基金Jabo Plantation Sdn Bhd(4C541 and 4C542)for the financial support.
文摘This study was focused on the preparation of water-soluble propolis extract as the natural preservative for perishable jaboticaba juice.A successive extraction and alkaline hydrolysis were performed to produce water-soluble propolis extract.The propolis extract was found to have a high content of phenolics and flavonoids,but a low concentration of wax.The hydrolysed propolis extract was added into jaboticaba juice and the treated juice quality was monitored for 2 weeks at 4℃.The results found that the performance of propolis extract was comparable with chemical preservative,sodium benzoate in similar amount(0.035%)used in the present study.The comparison was performed based on the physiochemical properties such as pH,titratable acidity,browning index and ascorbic acid content of juice.Ascorbic acid was the most reliable parameter to monitor the kinetic degradation of jaboticaba juice.Its degradation followed a first order kinetic model with a lower kinetic constant(0.1912 mg/mL/day)than that of non-treated juice(0.2073 mg/mL/day).The second reliable parameter was titratable acidity which could be used to monitor the rate of acid formation resulting from the breakdown of fruit sugars during degradation.The acidity of juice was slightly increased with storage time following zero order kinetics.The browning index was not suitable for juice quality monitoring as the addition of propolis would reduce flavylium cations of anthocyanins to be colourless.This non-thermal extraction followed by mild alkaline hydrolysis at pH 7.5 could produce good quality propolis extract,possibly as an alternative to chemical preservatives for jaboticaba juice.
