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Oligosaccharide Chitosan: Viscosity, Molecular Weight, Antibacterial Activity, and Impact of γ Radiation
Vu Ngoc Boi,
Nguyen Thi My Trang,
Dang Xuan Cuong,
Vu Thi Hoan,
Le Hai
Issue:
Volume 4, Issue 2, June 2020
Pages:
40-45
Received:
17 March 2020
Accepted:
30 March 2020
Published:
29 April 2020
Abstract: Chitosan is a bioactive polymer produced from shrimp and crab shells, etc. According to VASEP (Vietnam Association of Seafood Exporters and Producers), the production of raw shrimp cultured in Vietnam was about 800,000 tons in 2018. Therefore, the shrimp processing industry has generated about 320,000 tons of wastes, including heads and shells. If wastes are not utilized and managed in proper ways, it can lead to serious environmental problems. In our study, shrimp shells were used to produce chitosan and further obtained oligochitosan for application in food preservation. The cobalt-60 radiation technology has been used to segment chitosan into oligochitosan. The radiation dose applied to chitosan solution was in the range of 25 ÷ 50 kGy and in the range of 66 ÷ 166 kGy for chitosan flakes. The results showed that the chitosan solution had higher segmental efficiency compared to that of chitosan flakes. The antibacterial activities of oligosaccharide chitosan segmented from chitosan flakes were higher than those of oligosaccharide chitosan segmented from chitosan solution. The highest antibacterial activities were observed in the oligochitosan segmented from chitosan flakes at the radiation dose of 66 kGy for all tested bacteria: E. coli O157:H7, Salmonella typhimurium, Listeria monocytogenes, Staphylococcus aureus, Bacillus subtilis. In addition, oligochitosan segmented from chitosan flakes at the radiation dose of 66 kGy had higher antibacterial activities on bacteria gram (-) than bacteria gram (+). The strongest antibacterial activities on L. monocytogenes and B. subtilis at the concentration of 0.3125%.
Abstract: Chitosan is a bioactive polymer produced from shrimp and crab shells, etc. According to VASEP (Vietnam Association of Seafood Exporters and Producers), the production of raw shrimp cultured in Vietnam was about 800,000 tons in 2018. Therefore, the shrimp processing industry has generated about 320,000 tons of wastes, including heads and shells. If ...
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Effect of Drying Temperatures and Aids on Polyphenol Content, Antioxidant Activity, and β Glucosidase Enzyme Inhibition Activity of Powder Stylissa flexibilis
Dang Xuan Cuong,
Nguyen Thi Phuong Hien
Issue:
Volume 4, Issue 2, June 2020
Pages:
46-52
Received:
17 March 2020
Accepted:
2 April 2020
Published:
29 April 2020
Abstract: Sponge Stylissa flexibilis is Porifera belong to a medicine animal group in the Vietnam sea, contains numerous valuable bioactive substances. The study focused on the impact of spray-drying input temperatures (90°C, 100°C, 110°C, and 120°C) and aids (Maltodextrin, saccharose: maltodextrin mixture (1:1, w/w and 1:2, w/w)) on the physical-chemical properties (moisture content, solubility, and polyphenol content), antioxidant activities (mechanism Mo6+ and Fe3+), and inhibition enzyme β Glucosidase of sponge extract powder. The sponge was collected from the sponge in May 2017 in the Ninh Thuan sea. The results showed the polyphenol content, total antioxidant activity, reducing power activity, and β Glucosidase enzyme inhibition activity was affected by the temperature and aids of the drying process and got the highest value of 77.692 ± 2.025 mg phloroglucinol equivalent/100g DW, 98.526 ± 1.997 mg ascorbic acid equivalent/100g DW, 28.945 ± 0.754 mg FeSO4 equivalent/100g DW, and 75.38 ± 2.516/100 μg/ml was at 90°C, respectively, compared to the others. The moisture of powder was a negative-correlation to the increase of drying temperature. All the powder dissolved fully in the water. Polyphenol content and bioactivities (antioxidant activity, β Glucosidase enzyme inhibition activity) was a strong correlation with each other (R2>0.8) and a positive-correlation to drying temperature. The suitable condition for drying of active polyphenol powder was at 90°C and 10% of maltodextrin. Active polyphenol powder can be useful for applicating into functional foods and pharmaceutics.
Abstract: Sponge Stylissa flexibilis is Porifera belong to a medicine animal group in the Vietnam sea, contains numerous valuable bioactive substances. The study focused on the impact of spray-drying input temperatures (90°C, 100°C, 110°C, and 120°C) and aids (Maltodextrin, saccharose: maltodextrin mixture (1:1, w/w and 1:2, w/w)) on the physical-chemical pr...
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Effects of Seasonal Variations and Location on the Proximate Compositions of Vended Street Food in Parts of Port Harcourt, Rivers State
Oyet Gogomary Israel,
Achinewhu Simeon Chituru,
Kiin-Kabari David Barine,
Akusu Monday Ohwesiri
Issue:
Volume 4, Issue 2, June 2020
Pages:
53-61
Received:
25 March 2020
Accepted:
13 April 2020
Published:
30 April 2020
Abstract: This study examined the interaction effect of seasonal variations and locations on the proximate compositions of vended street food in parts of Port Harcourt metropolis. The study was carried out using complete randomized block design in factorial experiment. Three (3) Factorials were used (with factor A as Season, B as Location and C as Street Vended foods). The experiment was conducted in dry and raining seasons along the 3 locations (Makoba-station 1, Elekahia-station 2 and Rivers State University-station 3). The Six Food products investigated were roasted plantain, fish, yam, suya, meat pie and doughnuts that were purchased from parts of Port Harcourt city respectively. The foods were sampled twice each seasons and the mean results recorded. The Result for proximate composition of street vended foods during the raining and dry seasons, with moisture content ranged from RF1-3 Wet (58.90 - 62.53%) and Dry RF1-3 (52.55 - 59.56%), with the highest moisture content occurring in Fish at Makoba - 62.53% during the wet season, while the lowest moisture content was recorded by DN1-3 Wet (24.84 - 31.98%), Dry (19.08-23.52%) and showed that the Moisture content of each of the food types were significantly different (P<0.05) with respect to seasons and location. Ash, fat, protein, crude fibre and carbohydrate content of the street vended foods ranged from 0.65 – 3.32%, 0.68 – 14.43%, 1.03 – 47.35%, 1.25 – 6.45% and 0.04 – 51.25%, respectively. Suya samples from Makobar (SY1) gave high crude fibre of 6.45%. High carbohydrate of 51.25%, 49.55% and 47.19% were showed in samples DN1, DN2 and DN3, respectively and were significantly different (P<0.05) with respect to location except suya with values of 5.50%, 3.26% and 3.82% which were not significantly different (P>0.05) in spite of location. Three-way factorial analysis showed that the interaction effect of seasonal variation and location on the proximate composition of selected street vended foods were significantly different (P<0.05) and may be due to the processing and food handling methods, species, seasonal effects on the raw materials and not particularly about the location of food samples.
Abstract: This study examined the interaction effect of seasonal variations and locations on the proximate compositions of vended street food in parts of Port Harcourt metropolis. The study was carried out using complete randomized block design in factorial experiment. Three (3) Factorials were used (with factor A as Season, B as Location and C as Street Ven...
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Antioxidant Phlorotannin from Brown Algae Sargassum dupplicatum: Enzyme-assissted Extraction and Purification
Vu Ngoc Boi,
Nguyen Thi My Trang,
Dang Xuan Cuong,
Hoang Thai Ha
Issue:
Volume 4, Issue 2, June 2020
Pages:
62-68
Received:
8 April 2020
Accepted:
26 April 2020
Published:
19 May 2020
Abstract: The study focused on the enzyme-assisted extraction and the purification of antioxidant phlorotannin content from brown algae Sargassum dupplicatum commonly grown in Vietnam. Antioxidant activities were evaluated, consisting of total antioxidant activity and reducing power activity for the enzyme-assisted extraction. Antioxidant purified phlorotannin was analyzed total antioxidant activity, reducing power activity, DPPH free radical scavenging activity, and lipoxygenase inhibition activity. The treating condition of brown algae by enzyme consisting of enzyme kinds (termamyl enzyme, cellulose enzyme, viscozyme enzyme), the enzyme concentration (2.5, 5.0, 7.5, 10.0, 12.5, and 15.0% (v/v)), and the treating time of algae (1, 2, 3, 4, and 5 hours). Brown algae were then soaked in 96% ethanol with the ethanol-to-brown algae ratio of 30/1 (v/w) for 24 hours at the room temperature for antioxidant phlorotannin extraction that purified by using the liquid-to-liquid method and the gel chromatography of Sephadex LH 20. Antioxidant phlorotannin purification was determined to base on DEPT and 1H NMR spectrum. The results showed that 7.5% cellulase enzyme destroyed brown algae cell for 3 hours leading the best efficiency of antioxidant phlorotannin extraction from brown algae for 24 hours by 96% ethanol with the ethanol-to-brown algae ratio of 30/1 (v/w) at the room temperature. Phlorotannin content, total antioxidant activity, and reducing power activity corresponded to 4.45±0.11 mg phloroglucinol equivalent/g DW, 11.17±0.28 mg ascorbic acid equivalent/g DW, and 11.09±0.24 mg FeSO4 equivalent/g DW, respectively. Two fractions of antioxidant phlorotannin (17 to 28 and 36 to 45) were collected after purification, possessed 4.1 to 177.3 and 8.3 to 112.2 mg phloroglucinol equivalent per 1087.56 mg glue, respectively. Total antioxidant activity, reducing power, and DPPH free radical scavenging corresponded to 12.48 to 585.52 and 28.08 to 371.28 mg ascorbic acid equivalent/1087.56 mg glue, 15.6 to 765.44 and 33.28 to 486.72 mg FeSO4 equivalent/1087.56 mg glue, and 72.23 to 100% and 76.02 – 100%, respectively. Lipoxygenase enzyme inhibition activity got 62.83 to 87.4 µM and 66.19 to 87.09 µM linoleic acid equivalent/ 100µl extract, respectively. DEPT and 1H NMR spectrum showed phloroglucinol exist in two over fractions.
Abstract: The study focused on the enzyme-assisted extraction and the purification of antioxidant phlorotannin content from brown algae Sargassum dupplicatum commonly grown in Vietnam. Antioxidant activities were evaluated, consisting of total antioxidant activity and reducing power activity for the enzyme-assisted extraction. Antioxidant purified phlorotann...
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