An Extract and Fractions from Coffea arabica Sediment on Antioxidant and Anti-Tyrosinase Activities, and on the Quality of Whiteleg Shrimp (Litopenaus vannamei ) during Refrigerated Storage

Dao Thi Anh Phan,Hue Thi Ha,Tinh Trung Ho 한국식품영양과학회 2021 Preventive Nutrition and Food Science Vol.26 No.3

Coffea arabica sediment, a popular agro-by-product from the coffee juice processing industry, contains many phytochemicals, and it is often discarded as waste. The antioxidant and anti-tyrosinase activities of an ethanol extract and its active fractions obtained from Coffea arabica sediment was studied. Additionally, whiteleg shrimp (Litopenaeus vannamei) was treated with the extract and fractions, and the quality during refrigerated storage was evaluated. The most active fraction (P<0.05) fraction III from the Coffea arabica sediment extract showed a total phenolic content of 116.5 mg gallic acid equivalent/g, an inhibitory concentration of 50% value of 27.3 μg/mL in the 2,2-diphenyl-1-picryl hydrazyl test, an absorbance of 3.7 (at 1.0 μg/mL) in the reducing power assay, and 79.5% inhibition for the tyrosinase inhibition test (at 100 μg/mL). Whiteleg shrimp treated with PD-3 and crude extract (CE) retarded the growth of bacteria and spoilage microorganisms in comparison to the control (P<0.05). Lower values in pH, thiobarbituric acid reactive substances, and total volatile base content were enumerated in samples treated with PD-3 and CE (P<0.05) compared to controls. Loss in freshness, protein content, and melanosis formation declined with CE and PD-3 treatments. Our findings showed that Coffea arabica sediment has antioxidant and antimicrobial properties. Also, it could be a promising treatment in melanosis prevention, and a natural additive for extending the shelf life of whiteleg shrimp during refrigerated storage; thus an alternative to traditional sulfites.

Inhibition of Melanosis in Whiteleg Shrimp (Litopenaeus vannamei ) during Refrigerated Storage Using Extracts of Different Avocado (Persea americana Mill.) By-Products

Dao Thi Anh Phan,Trung Huu Bui,Tram Quynh Thi Doan,Nguyen Van Nguyen,Trieu Hai Ly 한국식품영양과학회 2021 Preventive Nutrition and Food Science Vol.26 No.2

Melanosis in shrimp usually leads to reduction in its shelf life and quality, which causes a significant loss in economic value of shrimp products. This study reports potential applications of nine ethanolic extracts of by-products, i.e., peel and/or seed from three Vietnamese avocado varieties as effective inhibitors of melanosis in whiteleg shrimp. Six out of nine shrimp samples treated with the prepared extracts (0.025%, w/v) reduced melanosis and lipid oxidation more significantly as compared to those treated with sodium metabisulfite (SMS, 1.25%, w/v) and control groups (treated with water) during 8-day storage at 4oC (P<0.05). These six extracts had mean gray values ranging from 47.0±0.7 to 57.3±0.4% were lower than those treated with SMS (mean gray of 39.8±0.4%). The inhibition of melanosis and lipid oxidation in shrimp for these extracts could be attributed to their high content of polyphenols [total phenolic content (TPC) from 44.5±1.1 to 144.7±1.9 mg gallic acid equivalents/g dried weight] and strong antioxidant activities [including 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, ferric reducing antioxidant power (FRAP), and tyrosinase enzyme inhibition]. Pearson statistical analysis showed strong correlation for melanosis inhibition to TPC and DPPH scavenging (r>0.80) followed by tyrosinase inhibition and FRAP (r>0.50). The findings obtained from this study suggest potential utilization of avocado by-product extracts as safe and cheap natural alternatives to traditional sulfites for anti-melanosis and shelf life extension of whiteleg shrimp.

Study on DPPH Free Radical Scavenging and Lipid Peroxidation Inhibitory Activities of Vietnamese Medicinal Plants

Phan Thi Anh Dao,Nguyen Xuan Hai,Nguyen Trung Nhan,Tran Le Quan,Nguyen Thi Thanh Mai 한국생약학회 2012 Natural Product Sciences Vol.18 No.1

Among 90 Vietnamese medicinal plant extracts investigated for their antioxidant activity by DPPH assay at various concentrations from 10 - 100 ?g/mL, 67 showed an inhibition rate over 50% at 100 ?g/mL; 47 had greater than 50% inhibition at 50 ?g/mL; 17 showed over 50% inhibition at 25 ?g/mL. 8 extracts which exhibited strong inhibitory activity more than 50% inhibition at 10 ?g/mL were further tested for lipid peroxidation inhibition by TBA assay. They displayed activity with IC50 values from 30.6 to 158.9 ?g/mL. Until now, this is the first report on antioxidant activity of the female flower of Borassus flabellifer, and the stem of Combretum latifolium, Embelia ribes, Spatholobus parviflorus, and Tetrastigma erubescens. Fractionations of the EtOAc extract prepared from S. parviflorus led to the isolation of protocatechuic acid (1), ferulic acid (2), epicatechin (3), and gallic acid (4). These compounds showed significant DPPH inhibitory activity with IC50 values from 6.5 to 23.6 ?M.

Antioxidant Constituents from the Stem of Tetrastigma erusbescense Planch. (Vitaceae)

Phan Thi Anh Dao,Tran Le Quan,Thi Thanh Mai 한국생약학회 2014 Natural Product Sciences Vol.20 No.1

A new natural product, tetrastigmol A (1), and several known compounds as flavonoids (2 - 8), steroids (9 - 10), bergenin and its derivative (11 - 12), stilbens (13 - 15), lignan (16), benzenecarboxylic derivative (17) and two norisoprenoid (18 - 19) were isolated from the stem of Tetrastigma erubescens Planch. (Vitateae). Their structures were determined on the basis of NMR spectroscopic data. This is the first report on chemical constituents of this plant. Compounds 1, 6 - 8 and 12 - 15 showed strong antioxidant activity using two methods including DPPH (1,1-diphenyl-2-picrylhydrazyl) free radical scavenging and lipid peroxidation inhibitory assays.

Fabrication and characterization of n-IZO / p-Si and p-ZnO:(In, N) / n-Si thin film hetero-junctions by dc magnetron sputtering

Dao, Anh Tuan,Phan, Thi Kieu Loan,Nguyen, Van Hieu,Le, Vu Tuan Hung Institute of Korean Electrical and Electronics Eng 2013 전기전자학회논문지 Vol.17 No.2

Using a ceramic target ZnO:In with In doping concentration of 2%, hetero-junctions of n-ZnO:In/p-Si and p-ZnO:(In, N)/n-Si were fabricated by depositing Indium doped n - type ZnO (ZnO:In or IZO) and Indium-nitrogen co-doped p - type ZnO (ZnO:(In, N)) films on wafers of p-Si (100) and n-Si (100) by DC magnetron sputtering, respectively. These films with the best electrical and optical properties were then obtained. The micro-structural, optical and electrical properties of the n-type and p-type semiconductor thinfilms were characterized by X-ray diffraction (XRD), RBS, UV-vis; four-point probe resistance and room-temperature Hall effect measurements, respectively. Typical rectifying behaviors of p-n junction were observed by the current-voltage (I-V) measurement. It shows fairly good rectifying behavior with the fact that the ideality factor and the saturation current of diode are n=11.5, Is=1.5108.10-7 (A) for n-ZnO:In/p-Si hetero-jucntion; n=10.14, Is=3.2689.10-5 (A) for p-ZnO:(In, N)/n-Si, respectively. These results demonstrated the formation of a diode between n-type thin film and p-Si, as well as between p-type thin film and n-Si..

The Impact of Financial Integration on Monetary Policy Independence: The Case of Vietnam

TRAN, Ha Hong,LE, Thao Phan Thi Dieu,NGUYEN, Vinh Thi Hong,LE, Dao Thi Anh,TRINH, Nam Hoang Korea Distribution Science Association 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.2

Along with the trend of financial globalization, Vietnam has undergone a process of increasing financial integration. The great capital inflow poses a problem for the monetary policy's ability to follow a planned target during the changes in the global financial markets. This paper aims to examine the impact of financial integration on monetary policy independence in Vietnam and investigate the role of foreign exchange reserves on this relationship. The research borrows from Mundell-Fleming's Trilemma theory. The results show that increasing financial integration reduces the independence of monetary policy in the short term, and foreign exchange reserves have not shown an apparent role in Vietnam. In addition, increasing exchange rate stability has a negative impact on the independence of monetary policy, but it has an impact on growing market confidence and partly supporting the management process of monetary policy in the short term. Therefore, in the long run, Vietnam needs to allow exchange rate flexibility more, but there should not be sudden changes; the size of foreign exchange reserves should be strengthened to facilitate the implementation of an independent monetary policy with an obvious impact in the context of an increasing scale of international capital flows in the future.