碩士 / 國立臺灣大學 / 園藝學研究所 / 92 / The carambola cultivars planted in Taiwan can be divided into tart cultivars and sweet cultivars. Sweet cultivars are eaten fresh while tart cultivars are used for food processing. Recently, due to the aging manpower of village and the increase in production cost, the carambola planting acreage of tart cultivars has decreased by year, the processing of carambola juice will eventually using the fermented sweet carambolas as raw material.
The result of this study showed that, the total soluble solids and total sugars decreased as fermentation proceeded; the titratable acidity significantly increased in the first week and then no prominent change throughout the fermentation; the formol nitrogen decreased dramatically in the first week but rose immediately in the second week and had no significant change afterward; the contents ascorbic acid decreased significantly in the first week and at the end of fermentation. Although the Hunter’s L, a, b values showed significantly different among the samples of different salt treatments after 91 days of fermentation, no visual difference in color among the samples was observed.
Fourteen volatile compounds were identified from the pickling brine samples with 7% NaCl treatment for 60 days, among which are: one hydrocarbon (tetradecane)、three alcohols (ethanol, isoamyl alcohol, nonanol)、one aldehyde (nonanal)、nine esters (ethyl acetate, isoamyl acetate, ethyl hexanoate, ethyl heptanoate, ethyl octanoate, ethyl nonanoate, ethyl decanoate, ethyl dodecanoate) and one ketone (β-ionone).
The total bacteria counts for the samples obtained from all treatments throughout the curing period ranged from 2.70×106 to 6.50×107CFU/mL, and the yeast counts ranged from 4.03×106 to 3.13×107CFU/mL. Yeast was identified as the major microorganism responsible for the fermentation of salted sweet carambola. Microbiological studies of colonies isolated from 7% NaCl treated brine were identified by API ID 32C. Two genus with 6 species of yeast (Candida krusei, Candida magnoliae, Candida pelliculosa, Candida valida, Kloeckera apiculata, Candida guilliermondii) were identified throughout the salted sweet carambola fermentation process. Lactic acid bacteria was found only in the early stage of sweet carambola fermentation with 5% NaCl treatment. No lactic acid bacteria was found after 28 days of fermentation. The only lactic acid bacteria identified from the brine samples of sweet carambola fermentation by API 50 CHL was Lactobacillus plantarum.
| Identifer | oai:union.ndltd.org:TW/092NTU05379022 |
| Date | January 2004 |
| Creators | Mei-Fang Tseng, 曾美芳 |
| Contributors | Ming-Jen Sheu, 許明仁 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 92 |
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