Progress 08/15/05 to 08/14/08
Outputs
OUTPUTS: 1. a cold pasteurized kava beverage has been tested for shelf life and consumer acceptability in a retail outlet in Honolulu. The product was deemed to be not acceptable by kava drinkers due to the residual taste of carbonic acid resulting from the cold pasteurization. 2. The detection of lactic acid producing bacteria in kava, based on a PCR-denaturing gradient gel electrophoresis (DGGE) was demonstrated to kava users in the 2008 annual kava festival. PARTICIPANTS: Ms. Padma Kandukuru, a graduate student in the Food Science program has completed her course work and graduated from the University of Hawaii in May 2008. She is now working in a research institute in India. Ms. MJ Hsieh, a graduate student in the Food Science program has completed her course work in December 2007 and is now working for Pepsi Company in Chicago. TARGET AUDIENCES: The kava bars in Honolulu and Maui have been informed about our findings in the year 2008 Kava Festival, which was held in Honolulu. The main findings reported are: 1. the presence of yeast and mold in kava stumps and ways of removing them, and 2. the concept and technical details of making a shelf-stable kava drinks, with a cold pasteurization process. PROJECT MODIFICATIONS: The main modification to this project is to switch the emphasis from cold pasteurization processing to microbial identification in year 2007. The main reason for this change is the unavailability of the cold pasteurizer in Florida, and the geographical distance to conduct research from Hawaii. Also, the establishment of a PCR work station in Hawaii has made the microbial finger-printing a logical approach to continue the project.
Impacts
1. The concept of making a shelf stable kava drink has been adopted by several kava bars in Honolulu and Maui. At least one product has been introduced successfully in the marketplace. 2. The positive identification of yeast and mold in some kava products has caused the elimination of using stumps in making the kava powder, because our results.
Publications
- The manuscript entitled "Microbial analysis of kava beverages using polymerase chain reaction and denaturing gradient gel electrophoresis" has been accepted for publication by the Journal of Food Microbiology in December 2008.
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Progress 08/15/06 to 08/14/07
Outputs
Both guava puree and kava beverage have been tested on the DP-CO2 machine located at the University of Florida campus. The guava puree is too thick to be pumped throuhg the system. The kava beverage needs to be strained and was processed successfully. The total bacteria count in the kava beverage was reduced from 10 to the forth (over 10,000 per gram) down to less than 100 (per gram). More importantly, the beverage was stored at 4C for six weeks and the total bacteria count remained under 100. The sensory test by a panel of regular kava drinkers indicated the taste of the processed product was fresh, but the carbon dioxide residues interfered with the taste, which needs improvement.
Impacts
Kava beverage can be cold pasteurized and the shelf life can be extended beyond six weeks. The carbon dioxide residues needs to be vacuumed to fully preserve the original kava taste. Guava puree has to be processed with the regular thermal pasteurization.
Publications
- No publications reported this period
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Progress 08/15/05 to 08/14/06
Outputs
We have collected guava puree made in Kauai and kava roots harvested in Oahu and sent them to Florida for testing. Both types of extracts went through the dense phase carbon dioxide (DP-CO2) pasteurizer with few technical difficulties. Approximately 40 liters of each extract were used. Both the fluid viscosities and back pressures were within the machine specifications. The kava extract has to be adjusted in pH from 5.5 to about 4.0 and then filtered to remove the acid precipitates formed. The cold pressure treatment (DP-CO2) accomplished a three log magnitude reduction in total bacteria counts. Storage test of the pasteurized kava extract showed the bacteria counts stayed at under 100 for about three weeks at 4C. Co-PI Dr. Bittenbender went to U. of Florida at the start of the project was instrumental in introducing kava juicing to the colleagues there. He demonstrated the traditional Polynesian way of making kava beverages and established the protocol of extracting
large quantities (in kg quantity) of kava. The shipping of frozen kava and guava purees from Hawaii to Florida has been proved feasible. Frozen materials arrived still in ice and in good conditions. Sensory evaluations have been used to monitor the raw materials and quality of the cold pasteurized juices. The cold pasteurized juice has more fresh taste than the thermally pasteurized counterparts.
Impacts
It is expected that shelf stable kava beverages can be commercially available within one year, with this cold pasteurization techniques.
Publications
- No publications reported this period
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