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The antioxidant potentials of buntan pumelo (Citrus grandis Osbeck) and its fermented products were determined. The essential oil from peel had higher total phenolic (214 mM) and flavonoid (134 mg QE/g of dried material) contents than those of different solvent extracts from fruit pulp. In addition, DPPH free radical-scavenging activity and ferric-reducing antioxidant power values determined for the essential oil were 26.1 ± 1.2% and 2.3 ± 0.3 mM, respectively, which were significantly higher than those of various fruit pulp extracts. The ethanol-fermented products of pumelo juice had higher total phenolic and flavonoid contents than those of fresh juice. For maintenance of the substantial antioxidant properties of pumelo products, ethanol-fermented juice rather than fresh or acetate-fermented juice is recommended. Through correlation analysis, the phenolic compounds in the fermented pumelo products were found to be the major contributors to the free radical-scavenging activity and ferric-reducing power. 相似文献
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Sheng-Hsien Lee Ku-Shang Chang Min-Sheng Su Yung-Sheng Huang Hung-Der Jang 《Food Control》2007,18(12):1547-1554
Chinese medicinal plant extracts were screened against some fungal strains, such as Aspergillus niger, Botrytis cinerea, Fusarium moniliforme, Glomerella cingulata, and Phyllosticta caricae. Plants were extracted with hot water, 80% methanol or acetone. Aliquots of the extracts at variable concentrations were then incubated with different fungal strains, and the minimum inhibitory concentrations (MICs) of each plant extract determined. In this study, the methanol extracts of Cinnamomum cassia had MIC values of 13.3 mg ml−1, when tested against F. moniliforme and P. caricae. The acetone extracts of C. cassia had MIC values of 8.3 mg ml−1 and 10 mg ml−1 respectively, when tested against B. cinerea and G. cingulata. The hot water extracts of C. cassia inhibited significantly the growth of A. niger, B. cinerea, F. moniliforme, and P. caricae with MIC values at 10, 11.7, 5, and 6.7 mg ml−1 respectively. The acetone extracts of Curcuma longa inhibited effectively P. caricae with the MIC value at 6.7 mg ml−1. To determine the stability, various plant extracts were stored at 4 and 25 °C over a period of one month and their effects on fungal growth examined. Results show that the acetone extracts of Cu. longa and Coptidis rhizoma maintained their activity against fungal strains when stored at 4 °C, but not at 25 °C. The methanol extracts of C. cassia lost a great portion of inhibitory activities but not all, after stored at 4 °C and 25 °C for one month. The effect of various combinations of these extracts on antimicrobial activity has also been examined. The combinations of herb extracts showed higher inhibitory effect towards tested fungi than that of individual extract. Results from these findings suggest that these herbal extracts may be used as natural antifungal agents to inhibit growth of foodborne pathogen. 相似文献
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Yuan-Geuy Hung-Yi Chuan-Liang Hong-Jen Chiun-Jye Hung-Der 《Sensors and actuators. B, Chemical》2009,141(2):575-580
A novel method for monitoring the growth of coliforms in milk was developed based on measuring the current change in an amperometric sensor. The sensor consists of a circuit with a homemade potentiostat and a pair of electrodes. The electrode was immersed in milk samples containing methylene blue with various concentrations of bacterial inoculums. The microbial metabolism led to the reduction of methylene blue resulting in a change of current. The time required to identify readily detectable change (detection time, DT) provided an approximate measurement of the amount of microorganisms in the initial inoculums. The sensor system used in this study has the selectivity towards coliform bacteria such as Escherichia coli and Enterobacter aerogenes. The calibration curve of DT against concentration of coliform showed a linear correlation coefficient (R2 = 0.9192) over the range of 102–108 CFU/mL. The sensor was able to detect the coliform bacteria at initial concentrations of 105 CFU/mL within 6 h, making it suitable for use in real-time monitoring of bacterial growth. This system has potential application in the detection of coliform concentration in milk at dairy farms when a proper selective media is designed. 相似文献
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Hung-Der Jang Ku-Shang Chang Yung-Sheng Huang Chuan-Liang Hsu Sheng-Hsien Lee Min-Sheng Su 《Food chemistry》2007,103(3):749-756
The principal antioxidant components and content of cinnamon (Cinnamomum cassia), turmeric (Curcuma longa) and golden thread (Coptidis rhizoma) extracts were determined using high performance liquid chromatography (HPLC) with UV detection. In general, C. cassia, C. longa and C. rhizoma extracts from domestic Taiwan were rich in cinnamaldehyde, curcumin, and berberin, respectively. The contents of cinnamaldehyde, curcumin, and berberin in the acetone extracts were 1911, 2029, and 840 mg l−1, respectively. The Folin–Ciocalteu method was used to measure the total phenolic concentrations of extracts, which had the content of 9.6 (C. cassia), 2.6 (C. longa), and 4.3 (C. rhizoma) mM l−1. In addition, DPPH radical-scavenging, ferric-reducing antioxidant power (FRAP), and ferric thiocyanate (FTC) assays were employed to measure antioxidant activities. The C. cassia fresh extracts had higher antioxidant activities which were 84–90% (DPPH), 17–33 μmol l−1 (FRAP), and 53–82% (FTC). The activities of C. longa fresh extracts were 22–44% (DPPH), 7–11 μmol l−1 (FRAP), and 53–81% (FTC) while C. rhizoma were 53–64% (DPPH), 18–26 μmol l−1 (FRAP), and 59–82% (FTC). 相似文献
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Chuan-Liang Hsu Hung-Der Jang Ming-Sheng Su Ku-Shang Chang Yung-Sheng Huang 《European Food Research and Technology》2008,226(4):809-815
Hydrogen peroxide (H2O2) residues are not permitted in food due to health concerns. An amperometric sensor based on a Nafion modified palladium (Pd)
electrode was developed for the rapid determination of the H2O2 residue in aseptically packaged beverages. A prepared Pd electrode shows a slowly increasing reaction upon repeating the
procedure of adding the same concentration of H2O2 into the reaction cell unless pretreating the electrode with cyclic voltammetry to obtain reproducible surfaces, whereas
a Nafion modified Pd electrode can reach stable reaction to H2O2 without any pretreatment. The interference level of ascorbic acid (the ration of electrochemical response to ascorbic acid
to the electrochemical response of H2O2) was calculated as 0.0004 for the Nafion modified Pd electrode. Interference (99.5%)from ascorbic acid was diminished by
Nafion membrane. The response of the sensor to H2O2 in distilled water is linear over the range of 0.25–15 μM (r
2 = 0.9956). The sensor developed in this study can efficiently determine H2O2 residues in commercial beverages with good linear correlation between spiked H2O2 concentration and detected H2O2 concentration, for winter melon-flavored drink, r
2 = 0.9904 in the range of 0.25–15 μM and for lemon-flavored tea, r
2 = 0.9927 in the range of 0.25–25 μM. 相似文献
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Hung-Der Jang Ku-Shang Chang Yuan-Guey Lee Sue-Jan Lee Chuan-Liang Hsu 《European Food Research and Technology》2009,229(2):349-355
A series piezoelectric quartz crystal (SPQC) sensor was developed for quantitative determination of Lactobacillus spp. populations in milk. When the electrodes were immersed in a reaction cell with bacterial inoculum, the change of frequency
was caused by the impedance change of the microbial metabolism. A significant frequency decrease was found due to the coagulation
of milk when the Lactobacillus spp. was cultivated in the media. The SPQC sensor system established in this study demonstrated the specificity and selectivity
for detection of Lactobacillus spp. in milk sample. The calibration curve of detection time against density of Lactobacillus spp. shows a linear correlation coefficient (R
2 = 0.8453) over the range of 102–2.4 × 105 CFU ml−1. The detection time was influenced by the addition of peptone and glucose. The sensor exhibited rapid (within 4 h) and enabled
real time monitoring of Lactobacillus spp. growth. This system is potentially applicable to detect Lactobacillus spp. concentration at local farm when a suitable temperature control device is adapted. 相似文献
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Yi-Huang Chang Chuan-Liang Hsu Chiun-Jye Yuan Shu-Fan Tang Hui-Jean Chiang Hung-Der Jang Ku-Shang Chang 《Materials science & engineering. C, Materials for biological applications》2011,31(7):1265-1270
Screen-printed carbon electrodes (SPCEs) were selectively etched by oxygen plasma. The coefficient of variance (CV) of inter-electrode reproducibility was reduced from 21.6 to 4.6. Studies of the surface by color-level-indexing histogram analysis, scanning electronic microscopy (SEM) and resistance revealed that the inter-electrode reproducibility correlated with complete etching of the resin binder from the SPCE surface. The quality of the electrode was differentiated by this color level index analysis. This technique has great potential for application in on-line quality control of the SPCE plasma-treating process when integrated with suitable image processing software. 相似文献
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Hung-Der Su Shou-Zen Chang Si-Chen Lee Tai-Ping Sun 《Electronics letters》1995,31(11):918-920
The Au/Cr/a-SiNx:H/(n)InAs/GaAs metal-insulator-semiconductor (MIS) capacitor was fabricated as a basic element of charge injection devices using plasma enhanced chemical vapour deposition. The electrical properties of the capacitor were analysed as a function of temperature using high frequency (1 MHz) capacitance-voltage measurements. It was demonstrated that the capacitor can still be biased into deep depletion at 180 K. When this capacitor is used as an integrated infrared detector in a charge injection device, it exhibits the capacity to detect infrared signals at a temperature of 180 K, higher than that of an InSb infrared detector (77 K), and the device can be cooled thermoelectrically 相似文献
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Hung-Der Su Bi-Shiou Chiou Shien-Yang Wu Ming-Hsung Chang Kuo-Hua Lee Yung-Shun Chen Chih-Ping Chao Yee-Chaung See Sun J.Y.-C. 《Electron Devices, IEEE Transactions on》2003,50(6):1543-1544
Small gate area with short gate length reduces the C-V distortion of ultrathin oxide devices, but results in high parasitic capacitance/total capacitance ratio. The floating well method can exclude the parasitic capacitance to obtain accurate inversion oxide thickness without using any dummy pattern. It is suitable for nano technology. 相似文献
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