Many epidemiologic studies indicate that plant-based diets delay the ageing process and reduces the risk of various lifestyle diseases such as metabolic syndrome, cardiovascular diseases and cancers. The compounds which are largely responsible for those protective effects are phytochemicals such as ...
Many epidemiologic studies indicate that plant-based diets delay the ageing process and reduces the risk of various lifestyle diseases such as metabolic syndrome, cardiovascular diseases and cancers. The compounds which are largely responsible for those protective effects are phytochemicals such as polyphenolic compounds which have strong antioxidant properties. Berry fruits, such as blueberry, aronia, grape, blackberry and raspberry are a particularly rich sources of antioxidants. Especially, blueberry has been increased interest gained over recent years due to their health potentials. The phytochemiclas are represented by polyphenolic compounds such as anthocyanins, flavonols and phenolic acids. Therefore, it is necessary to enchance the contents of bioactive compounds as anthocyanin and polyphenols to improve a health benefits. This study was carried out to investigate changes of bioactive compounds such as polyphenolic, anthocyanins, and stilbene compounds, and changes of antioxidant activities during the fermentation of blueberry homogenates by 4 yeasts (Fermivin, SRCM 100935, SRCM 100936 and SRCM 100938) and by a combination of yeasts and Asp. niger cellulase. the results are as follows.
1. The solid content of blueberry homogenates decreased during fermentation period at 12° Brix of control and decreased to 4-5° Brix after 9 days. There was no difference in the use of yeasts alone and yeast+cellulase mixed treatment during fermentation. Free sugar content decreased rapidly as the fermentation progressed and completely disappeared at the end of 7 days. Yeast+cellulase mixed treatment was more effective than yeast alone treatment.
2. Total polyphenol and total flavonoid contents were increased during the fermentation process and Fermivin treatment was the most increased among the four yeasts used in this study. When the changes of phenolic acid and flavonoid composition in fermentation period were investigated by HPLC analysis, gallic acid was detected small amount in the non fermented blueberry homogenate (control), but it was increased greatly after 7 days of fermentation, and neochlorogenic acid and quercetin also showed similar tendencies. On the other hand, in the yeast+cellulase mixed treatments, chlorogenic acid decreased rapidly as fermentation period increased, while caffeic acid increased steadily. The results suggest that chlorogenic acid (3-O-caffeoylquinic acid) was hydrolyzed into caffeic acid and quinic acid by chlorogenic acid hydrolase (CAH) contained in the crude cellulase from Asp. niger. Total anthocyanin content was not significantly different between control and yeast treatments, but petunidin 3-O-glucoside and malvidin 3-O-glucoside steadily increased when fermented with Fermivin, reaching the maximum value at the fermentation time of 7 days.
3. Stilbene compounds, trans-piceid and trans-resveratrol identified in blueberry homogenate by comparison of retention time and UV profiles by HPLC-DAD with those of authentic compounds. In particular, trans-piceid (trans-resveratrol 3-β-D-glucoside) decreased while trans-resveratrol content tended to increase in fermivin and SRCM 100936 and yeast+cellualse mixed samples. These results suggest that trans-piceid was hydrolyzed into trans-resveratrol by β-glucosidases secreted by yeasts either β-glucosidases from Asp. niger cellulase during fermentation.
5. The antioxidant activities by free radical scavenging activities (DPPH and ABTS) and the ferric reducing power (FRAP) assay increased when the blueberry homogenate were fermented by yeasts or combined treatment of yeasts and Asp. niger cellulase. The result suggest that the enhancements of antioxidant activities in fermented blueberry homogenates are the results of enhancements of bioactive compounds including phenolic acids, flavonoids and stilbene in free forms with the decrease of free sugars.
Keywords: blueberry, fermentation, yeast, cellulase, polyphenol, antioxidant activity.
Many epidemiologic studies indicate that plant-based diets delay the ageing process and reduces the risk of various lifestyle diseases such as metabolic syndrome, cardiovascular diseases and cancers. The compounds which are largely responsible for those protective effects are phytochemicals such as polyphenolic compounds which have strong antioxidant properties. Berry fruits, such as blueberry, aronia, grape, blackberry and raspberry are a particularly rich sources of antioxidants. Especially, blueberry has been increased interest gained over recent years due to their health potentials. The phytochemiclas are represented by polyphenolic compounds such as anthocyanins, flavonols and phenolic acids. Therefore, it is necessary to enchance the contents of bioactive compounds as anthocyanin and polyphenols to improve a health benefits. This study was carried out to investigate changes of bioactive compounds such as polyphenolic, anthocyanins, and stilbene compounds, and changes of antioxidant activities during the fermentation of blueberry homogenates by 4 yeasts (Fermivin, SRCM 100935, SRCM 100936 and SRCM 100938) and by a combination of yeasts and Asp. niger cellulase. the results are as follows.
1. The solid content of blueberry homogenates decreased during fermentation period at 12° Brix of control and decreased to 4-5° Brix after 9 days. There was no difference in the use of yeasts alone and yeast+cellulase mixed treatment during fermentation. Free sugar content decreased rapidly as the fermentation progressed and completely disappeared at the end of 7 days. Yeast+cellulase mixed treatment was more effective than yeast alone treatment.
2. Total polyphenol and total flavonoid contents were increased during the fermentation process and Fermivin treatment was the most increased among the four yeasts used in this study. When the changes of phenolic acid and flavonoid composition in fermentation period were investigated by HPLC analysis, gallic acid was detected small amount in the non fermented blueberry homogenate (control), but it was increased greatly after 7 days of fermentation, and neochlorogenic acid and quercetin also showed similar tendencies. On the other hand, in the yeast+cellulase mixed treatments, chlorogenic acid decreased rapidly as fermentation period increased, while caffeic acid increased steadily. The results suggest that chlorogenic acid (3-O-caffeoylquinic acid) was hydrolyzed into caffeic acid and quinic acid by chlorogenic acid hydrolase (CAH) contained in the crude cellulase from Asp. niger. Total anthocyanin content was not significantly different between control and yeast treatments, but petunidin 3-O-glucoside and malvidin 3-O-glucoside steadily increased when fermented with Fermivin, reaching the maximum value at the fermentation time of 7 days.
3. Stilbene compounds, trans-piceid and trans-resveratrol identified in blueberry homogenate by comparison of retention time and UV profiles by HPLC-DAD with those of authentic compounds. In particular, trans-piceid (trans-resveratrol 3-β-D-glucoside) decreased while trans-resveratrol content tended to increase in fermivin and SRCM 100936 and yeast+cellualse mixed samples. These results suggest that trans-piceid was hydrolyzed into trans-resveratrol by β-glucosidases secreted by yeasts either β-glucosidases from Asp. niger cellulase during fermentation.
5. The antioxidant activities by free radical scavenging activities (DPPH and ABTS) and the ferric reducing power (FRAP) assay increased when the blueberry homogenate were fermented by yeasts or combined treatment of yeasts and Asp. niger cellulase. The result suggest that the enhancements of antioxidant activities in fermented blueberry homogenates are the results of enhancements of bioactive compounds including phenolic acids, flavonoids and stilbene in free forms with the decrease of free sugars.
Keywords: blueberry, fermentation, yeast, cellulase, polyphenol, antioxidant activity.
주제어
#Blueberry fermentation yeast cellulase polyphenol antioxidant activity
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