Impact of diuron applications to commercial catfish ponds on musty‐odor cyanobacteria, musty off‐flavor compound concentrations, and catfish fillet flavor quality

Sodium carbonate peroxyhydrate (SCP) was applied to seven commercial catfish ponds in Mississippi to study the effects of treatment on fish flavor and pond ecology. The seven ponds were treated on alternate days in the morning with two doses of SCP at 55 kg hectare−1 (average depth 1-1.6 m). In three of the ponds, a potent 2-methylisoborneol (MIB) producing planktonic Oscillatoria chalybea-like species that was initially present was absent from the water column after treatment. In addition, the fish from two of these ponds were judged on-flavor 7 to 10 days after treatment. The off-flavor chemicals in three other ponds were diminished when measured seven days after treatment and fish were harvested from two of these ponds 10-14 days after treatment. The fish from the other two ponds were harvested 21 days after treatment. In the sixth pond, the predominant algal species was a 2-methylisoborneol producing O. chalybea-like species at 380 cells ml−1 and the treatment was ineffective. The treatment was most successful when off-flavor was less than two months duration and where application of the chemical was accomplished uniformly over the entire pond surface.

Download Full-text

The Relationship between Concentration and Sensory Properties of 2-Methylisoborneol and Geosmin in Drinking Water

Water Science & Technology ◽

10.2166/wst.1988.0218 ◽

1988 ◽

Vol 20 (8-9) ◽

pp. 11-17 ◽

Cited By ~ 4

Author(s):

T. Ito ◽

T. Okumura ◽

M. Yamamoto

Keyword(s):

Drinking Water ◽

Water Temperature ◽

Forced Choice ◽

Residual Chlorine ◽

Mixing Ratio ◽

Consumer Panel ◽

Triangle Method ◽

Musty Odor ◽

The Relationship ◽

Mixed Samples

The study of the relations between the senses of smell and taste and odorant concentration is important for the solution of odor problems. The threshold concentrations of odor and taste (TOC, TTC) of 2-methylisoborneol (MIB) and geosmin were measured by the non-forced choice triangle method using 12-20 panelists. Both TOC and TTC were found to be functions of water temperature and the concentration of residual chlorine. The TOC and TTC of mixed samples were rather lower than the concentrations calculated from the mixing ratio. The sensitivities of the consumer panel and the number of musty odor complaints from consumers are related to MIB or geosmin concentration. The ratio of the number of complaints to MIB (or geosmin) concentration decreased after maximum complaint, but the sensitivity of the consumer panel remained the same.

Download Full-text

The relationship between musty-odor-causing organisms and water quality in Lake Biwa

Water Science & Technology ◽

10.2166/wst.1995.0426 ◽

1995 ◽

Vol 31 (11) ◽

pp. 153-158 ◽

Cited By ~ 3

Author(s):

M. Kajino ◽

K. Sakamoto

Keyword(s):

Water Quality ◽

Data Analysis ◽

Green Algae ◽

Analytical Methods ◽

Lake Biwa ◽

Blue Green Algae ◽

Odor Compounds ◽

Musty Odor ◽

The Relationship

Musty odor has occurred annually in Lake Biwa since 1969. Osaka municipal waterworks, which is located downstream of Lake Biwa, has made many efforts to treat musty-odor compounds produced in Lake Biwa from spring through autumn. With the development of analytical methods for the determination of musty-odor compounds, we have been able to confirm that planktonic blue-green algae are the major causes of the musty-odor occurrences. The relationship between the growth of blue-green algae and the water quality was not so apparent. However, through our data analysis focusing on the relationship between musty-odor occurrences due to Phormidium tenue or Oscillatoria tenuis and some nutrients in Lake Biwa, we found that the concentration of nitrate in water may be an important parameter for the estimation of growth of the algae and the musty-odor behavior.

Download Full-text

PTSA (pressure and thermal swing adsorption) method to remove trihalomethanes from drinking water

Water Science & Technology ◽

10.2166/wst.1997.0283 ◽

1997 ◽

Vol 35 (7) ◽

pp. 243-250 ◽

Cited By ~ 1

Author(s):

Shigekazu Nakano ◽

Tomoko Fukuhara ◽

Masami Hiasa

Keyword(s):

Drinking Water ◽

Residual Chlorine ◽

Remarkable Difference ◽

Adsorption Method ◽

Heating And Cooling ◽

Point Of Use ◽

Thermal Swing Adsorption ◽

Long Time ◽

Musty Odor ◽

Vacuum Heating

It has been widely recognized that trihalomethanes (THMs) in drinking water pose a risk to human health. THMs can be removed to a certain extent by the conventional point-of-use (POU) unit which is composed of activated carbon (AC) and microfilter. But it's life on THMs is relatively shorter than on residual chlorine or musty odor. To extent the life of AC adsorber, pressure and thermal swing adsorption (PTSA) was applied by preferential regeneration of chloroform. PTSA was effective to remove THMs, especially chloroform. Adsorption isotherms of chloroform at 25 and 70°C showed a remarkable difference so that thermal swing was considered effective. Chloroform was also desorbed by reducing pressure. By vacuum heating at 70°C, chloroform was almost desorbed from AC and reversible adsorption was considered possible. A prototype of POU unit with PTSA was proposed. Regeneration mode would consist of dewatering, vacuum heating and cooling (backwashing). The unit was maintained in bacteriostatic condition and could be used for a long time without changing an AC cartridge.

Download Full-text

Characteristic fingerprints and volatile flavor compound variations in Liuyang Douchi during fermentation via HS-GC-IMS and HS-SPME-GC-MS

Food Chemistry ◽

10.1016/j.foodchem.2021.130055 ◽

2021 ◽

pp. 130055

Author(s):

Yi Chen ◽

Pao Li ◽

Luyan Liao ◽

Yeyou Qin ◽

Liwen Jiang ◽

...

Keyword(s):

Flavor Compound ◽

Volatile Flavor Compound ◽

Volatile Flavor

Download Full-text

An ADH toolbox for raspberry ketone production from natural resources via a biocatalytic cascade

Applied Microbiology and Biotechnology ◽

10.1007/s00253-021-11332-9 ◽

2021 ◽

Author(s):

Aileen Becker ◽

Dominique Böttcher ◽

Werner Katzer ◽

Karsten Siems ◽

Lutz Müller-Kuhrt ◽

...

Keyword(s):

Alcohol Dehydrogenase ◽

Genetically Modified Organisms ◽

Optical Purity ◽

High Yield ◽

Alcohol Dehydrogenases ◽

Flavor Compound ◽

Raspberry Ketone ◽

Cofactor Recycling ◽

Cosmetic Industry ◽

Key Points

Abstract Raspberry ketone is a widely used flavor compound in food and cosmetic industry. Several processes for its biocatalytic production have already been described, but either with the use of genetically modified organisms (GMOs) or incomplete conversion of the variety of precursors that are available in nature. Such natural precursors are rhododendrol glycosides with different proportions of (R)- and (S)-rhododendrol depending on the origin. After hydrolysis of these rhododendrol glycosides, the formed rhododendrol enantiomers have to be oxidized to obtain the final product raspberry ketone. To be able to achieve a high conversion with different starting material, we assembled an alcohol dehydrogenase toolbox that can be accessed depending on the optical purity of the intermediate rhododendrol. This is demonstrated by converting racemic rhododendrol using a combination of (R)- and (S)-selective alcohol dehydrogenases together with a universal cofactor recycling system. Furthermore, we conducted a biocatalytic cascade reaction starting from naturally derived rhododendrol glycosides by the use of a glucosidase and an alcohol dehydrogenase to produce raspberry ketone in high yield. Key points • LB-ADH, LK-ADH and LS-ADH oxidize (R)-rhododendrol • RR-ADH and ADH1E oxidize (S)-rhododendrol • Raspberry ketone production via glucosidase and alcohol dehydrogenases from a toolbox Graphical abstract

Download Full-text

Effects of Different Winemaking Yeasts on the Composition of Aroma-Active Compounds and Flavor of the Fermented Jujube Wine

Processes ◽

10.3390/pr9060970 ◽

2021 ◽

Vol 9 (6) ◽

pp. 970

Author(s):

Yan Zhao ◽

Xiaobin Yu ◽

Fengtao Zhu ◽

Guangpeng Liu ◽

Le Chu ◽

...

Keyword(s):

Large Scale ◽

Starter Cultures ◽

Flavor Quality ◽

Wine Quality ◽

Active Compounds ◽

Ethyl Hexanoate ◽

Optimal Starter ◽

Phenethyl Acetate ◽

Ethyl Decanoate

For the winemaking bioprocess of jujube wine, the selection of optimal starter cultures is one of the major concerns before fermentation. In this study, we investigated the effects of different winemaking yeasts on the composition of aroma-active compounds in the fermented jujube wine and identified the principal components that determine the flavor quality. It showed that the starter winemaking yeasts produced a total of 43 aroma-active compounds, of which esters (e.g., ethyl caprylate, ethyl decanoate, ethyl hexanoate, and phenethyl acetate) contribute more to the wine quality attributes, especially for the improvement of the aroma. Moreover, the composition of aroma-active compounds, for example, the ratio of the content of esters and alcohols, exerts a great impact on the flavor quality of jujube wine. Different starter winemaking yeasts resulted in significant differences in the composition (both species and content) of aroma-active compounds, and thus formed different flavors in the jujube wine. Thus, we propose that screening of a desirable starter winemaking yeast is essential before the fermentation of jujube wine at a large scale, and more considerations should be taken into the resulting composition of aroma-active compounds.

Download Full-text