Production and antioxidative properties of lactic-fermented Chinese cabbage
|乳酸發酵大白菜;乾鹽法;捕捉DPPH自由基能力;還原力;螯合亞鐵離子能力;lactic-fermented Chinese cabbage;dry-salt method;DPPH-radical scavenging effect;Fe2+-ion chelating ability;reducing activities
本研究利用乾鹽法（dry-salt method）以及簡單的配料來進行韓式口味之乳酸發酵白菜（lactic acid fermented cabbage）的製造，探討食鹽與溫度發酵對乳酸發酵白菜之影響，並探討發酵過程、添加雙叉桿菌對乳酸發酵白菜抗氧化活性以及乳酸發酵白菜於貯存過程中之菌相變化。酸發酵白菜隨著發酵時間增加，可滴定酸度增加、pH值下降；乳酸菌在發酵前期很快的成為主要優勢菌種，其中Leuconostoc mesenteroides為發酵初期的主要菌種，之後由Lactobacillus plantarum取而代之；發酵溫度對乳酸發酵白菜的乳酸菌相影響較食鹽明顯，溫度較高（25℃）時，L. mesenteroides與L. plantarum消長速度較快；發酵溫度較低（18℃）時，食鹽對菌數影響較顯著。乳酸發酵白菜經消費者喜好性評估，結果顯示以3%食鹽處理、25℃發酵溫度者較受消費者喜愛。氧化活性方面，萃取溶劑與發酵過程對白菜混合物（未發酵）的抗氧化活性有明顯的影響。ㄧ般而言，發酵過程對於白菜混合物之甲醇萃取物的螯合亞鐵離子能力與還原力並無影響，然而水萃取物部分之抗氧化活性卻有明顯的降低，甲醇萃取物比水萃取物具有較高的捕捉DPPH自由基能力與還原力, 其中發酵白菜的甲醇萃取物具有最高的捕捉DPPH自由基能力。萃取溶劑的種類與發酵過程對於萃取物中的總酚與類黃酮含量亦有影響，發酵過程會增加甲醇萃取物中的總酚含量，但卻會降低水萃取物中的類黃酮的含量，但大白菜混合物與乳酸發酵白菜萃取物的抗氧化變化與其中所含的總酚與類黃酮含量變化並不完全ㄧ致。加益生性雙叉桿菌Bifidobacterium breve BCRC 11846、B. lactis Bb-12、B. infantis BCRC 14602以及B. bifidum BCRC 14615至乳酸發酵白菜中，清除DPPH自由基清除能力情形，除了B. breve 11846與未添加之控制組的能力無顯著差異，其他添加雙叉桿菌之乳酸發酵白菜對於捕捉DPPH．能力較控制組具有顯著的促進效果；添加雙叉桿菌組的水萃取之螯合亞鐵離子能力明顯較未添加者佳，無論是甲醇萃取物或是水萃取物以添加B. infantis BCRC14602表現最佳，與其他組別具有顯著差異（p < 0.05）；還原力方面，添加雙叉桿菌之乳酸發酵白菜的水萃取物明顯較未添加之控制組的還原力好（p < 0.05），甲醇萃取物的還原力比水萃取物為佳，其中以添加B. lactis Bb12的乳酸發酵白菜甲醇萃取物表現最佳。綜合抗氧化實驗結果顯示添加雙叉桿菌的乳酸發酵白菜具有促進抗氧化能力效果，但因添加之雙叉桿菌菌種不同亦會有所差異。存過程對添加雙叉桿菌的乳酸發酵白菜的酸鹼值與可滴定酸方面，無顯著影響，但其中總乳酸菌數與雙叉桿菌的存活有明顯的影響，乳酸菌數由原先8 log CFU/g貯存至第三週時已減少至6~7 log CFU/g，有明顯差異（p < 0.05）；雙叉桿菌數方面，貯存至第2週時均減少至4 log CFU/g，有明顯的差異（p < 0.05）。抗氧化能力方面，無論有無添加雙叉桿菌之乳酸發酵白菜之甲醇萃取物的抗氧化能力（捕捉DPPH．能力與還原力），並未隨著貯存時間增加有明顯變化，但是水萃取物之抗氧化能力隨著貯存時間增加有明顯減少的變化。
This study tries to produce lactic acid fermented cabbage similar to kimchi in Korea with a dry-salt method and simple formula, investigate the effects of temperature and NaCl on lactic acid fermented cabbage. Besides, antioxidant activity was determined and the effects of fermentation on the change of antioxidant activity, the antioxidative activity of supplemented with bifidobacteria into lactic acid fermented cabbage and storage were also investigated.esults showed that pH value decreased and titratable acidity increased following with fermentation time. Lactic acid bacteria (LAB) became the dominant flora after 1 day. Leuconostoc mesenteroides appeared at the earlier stage of fermentation and Lactobacillus plantarum appeared in the later stage. The changes of microflora during fermentation were much more dependent on temperature than on salt concentrations. L. mesenteroides decreased much more rapidly at 25℃ than at 18℃. The microbial growth in lactic acid fermented cabbage fermentation was significantly changed by sodium chloride within the range of 2-3% at 18℃. However, the influence of salt concentration was not significant while fermentation was carried out at 25℃. Hedonic sensory evaluation of lactic acid fermented cabbage was prepared at either 2% or 3% salt concentration and fermented at 25℃ for 2 day and 18℃ for 2.5 day. It showed that the lactic acid fermented cabbage dehydrated by 3% salt concentration, and fermented at 25℃ was better than others.ntioxidant activity observed on Chinese cabbage mixture may vary with extraction solvents and fermentation. Generally, the methanol extract of cabbage mixture showed a higher DPPH radical scavenging activity and reducing activity than did the water extract. Although fermentation did not alter the Fe2+-chelating ability and reducing activity of the methanol extract of the cabbage mixture, it reduced these same antioxidant activities in the water extract. Among the various extracts examined, the methanol extract of fermented cabbage showed the highest DPPH-radical scavenging effect. Additionally, the type of solvent and fermentation were also found to affect the total phenolic and flavonoid content of the extracts. Fermentation increased the total phenolic content of the methanol extract, while reducing the total flavonoid content of the water extract. Furthermore, changes in the antioxidant activity observed on the extracts of cabbage mixture and fermented cabbage did not coincide exactly with the content of total phenolics and total flavonoids.upplemented with B. breve BCRC 11846、B. lactis Bb-12、B. infantis BCRC 14602以及B. bifidum BCRC 14615 into lactic acid fermented cabbage to 107 CFU/g, there is no significantly difference on total lactic acid bacteria, L. mesenteroides, L. plantarum, pH value and titratable acid. The extracts of supplemented probiotic bifidobacteria of lactic acid fermented cabbage except supplemented B. breve 11846 showed a higher DPPH radicals scavenging effect than control (without supplemented). Moreover, the extracts of lactic acid fermented cabbage supplemented B. infantis BCRC14602 showed the best Fe2＋-chelating ability. The methanol extract of lactic acid fermented cabbage supplemented B. lactis Bb12 showed the best reducing power and the water extracts of lactic acid fermented cabbage supplemented bifidobacteria showed a higher DPPH radicals scavenging effect than control. Furthermore, supplemented bifidobacteria to lactic acid fermented cabbage may enhance the antioxidative activity, but have some variations in variety of bifidobacteria supplemented.hanges of lactic acid fermented cabbage supplemented with bifidobacteria on the total lactic acid bacteria, bifidobacteria, and antioxidative activity during storage at 4℃. there are no significant change at pH value and titratable acid, total lactic acid bacteria of fermented cabbage supplemented with/without bifidobacteria showed that there was not a significant decrease during the first 2 weeks while being storage at about 8 log CFU/g. However, there was a significant decrease to 6~7 log CFU/g at the third week (p<0.05), and an even more significant decrease to the remaining 4~5 log CFU/g at the fourth week (p<0.05). Form the second week the numbers of bifidobacteria were significantly decreased to 4 log CFU/g, but and antioxidative activity of methanol extracts showed no significant decrease or change during storage, but the water extracts significantly decreased during storage and the longer the storage time, the less antioxidative activity.
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