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Search Result of "Acetobacter aceti"

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ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Semi-Continuous Production Process of Corn Vinegar in Stirred Tank Reactor Using Fixation of Acetobacter aceti WK on Surface of Loofa Sponge)

ผู้เขียน:Warawut Krusong, Panit Petch-nom, Prapas Pinviset

สื่อสิ่งพิมพ์:pdf

Abstract

Previous study by the authors showed that an alternative process to an airlift fermenter in the green vinegar production process could use a loofa sponge (a natural agricultural fibrous material) as the supporting material for Acetobacter aceti WK. Subsequently, aim of this study was production of green vinegar in a stirred tank reactor (STR). The filtered corn wine was supplied to the STR using fixation of A. aceti WK cells on the surface of a loofa sponge cut to a thickness of 2.5 cm. The loofa sponge was left in the STR until 60% of fermenting volume had been used. The charging rate of fresh, filtered corn wine for a semi-continuous production process was investigated. The highest acidification rate (ETA) was achieved at a charging rate of 30%. After 14 d of the adaptation period, the average acidity of 4.1?0.1% was produced during six cycles of fermentation at 30?C and 1vvm aeration supply within 40 d, while the ETA was in the range 0.0028%/h to 0.0067%/h. Scanning electron microscopy (SEM) showed that the surface of the loofa sponge acted as a good fibrous structure for cell fixation of A. aceti WK in the STR.

Article Info

Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 044, Issue 3, May 10 - Jun 10, Page 454 - 461 | PDF | Page

ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Antioxidant Properties of Roselle Vinegar Production by Mixed Culture of Acetobacter aceti and Acetobacter cerevisiae)

ผู้เขียน:Jirasak Kongkiattikajorn

สื่อสิ่งพิมพ์:pdf

Abstract

Roselle (Hibiscus sabdariffa) has been used in folk medicine and as a treatment for diseases and cancer. The objective of this study was to enhance the acetic acid production and the antioxidant activities (AOA) of Roselle vinegar using mixed culture fermentation. The Roselle wine was produced in a batch reactor. The kinetic parameters obtained for wine fermentation using Saccharomyces cerevisiae were: maximum ethanol production = 63.47 g.L-1, ethanol production rate = 2.25 g.L-1. hr-1, product (ethanol) yield coefficient = 0.45 and cell mass yield coefficient = 1.53. Using a mixed culture of Acetobacter aceti and Acetobacter cervisiae, the wine vinegar process optimization ranges for initial concentrations of ethanol and acetic acid as independent variables were 63.47 and 69.21 g.L-1, respectively. Roselle was processed into juice fermentation and vinegars. The total phenolics, total anthocyanins, and antiradical activity (1-1 diphenyl-2-picryl hydrazyl radical-scavenging (DPPH) method) were determined. Acetification increased the total anthocyanin content, total polyphenols and antioxidant activities. Correlations indicated that anthocyanins made greater significant contributions than did phenolics to the antioxidant activities of the products. The antiradical activity of wine from Roselle juice was high with an effective concentration which inhibited the DPPH activity by 50% (EC50) of 14.95 mg.L-1. The antioxidant activity of the vinegar product was high with an EC50 of 0.72 mg.L-1. The results indicated that fermentation is a better method for obtaining higher antioxidant activity of Roselle products. Furthermore, acetification significantly increased the anthocyanins and antioxidant activities.

Article Info

Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 048, Issue 6, Nov 14 - Dec 14, Page 980 - 988 | PDF | Page