• Korean Journal of Medicinal Crop Science
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• v.20 no.6
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• pp.472-478
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• 2012

This study was carried out to investigate solid-state fermentation method using cellulolytic lactic acid bacteria Lactobacillus plantarum TO-2100 in order to increase piperidine alkaloid contents in mulberry leaves. Piperidine alkaloid, one type of which include 1-deoxynojirimycin (1-DNJ), is known to inhibit ${\alpha}$-glycosidase activities. Using this strain, the optimal solid-state fermentation conditions on mulberry leaves powder were found as the following: initial moisture content, temperature and relative humidity were 20%, $30{\sim}35^{\circ}C$ and 60 ~ 70%, respectively, and the fermentation time was 72 hrs. The piperidine alkaloid contents in the fermented mulberry leaves were 2.86% on dry powder, which is 7-fold increase from that of non-fermented mulberry leaves. The 1-deoxynojirimycin contents after applying preparative thin layer chromatography were 2.02% on dry powder, which is 8 times higher than that of non-fermented mulberry leaves. ${\alpha}$-Glycosidase activities was inhibited by 65.7 ~ 84.7% with 3 ~ 5% treatments of hot-water extracts of the fermented mulberry leaves, compared to 16.2 ~ 40.2% with 3 ~ 5% treatments of hot-water extracts of non-fermented mulberry leaves. Therefore, the results suggest that solid-state fermentation method does indeed increase of piperidine alkaloid contents on mulberry leaves.

• Journal of Sericultural and Entomological Science
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• v.51 no.2
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• pp.164-172
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• 2013

This study was carried out to investigate functional quality characteristics of extract obtained after sugar-leaching for 12 weeks (SLE) and extract obtained after lactic acid fermentation for 8 weeks (LFE) of mulberry leaves. The yield, sugar content, pH, and total acidity of SLE were 27%, 43 $^{\circ}Brix$, 4.6, and 0.45%. The yield, sugar content, pH, and total acidity of LFE were 166%, 33 $^{\circ}Brix$, 3.6, and 1.17% respectively. The lactic acid bacteria viable numbers ($1.2{\times}10^{10}$ CFU/ml) of LFE were more than those of SLE ($2.8{\times}10^2$ CFU/ml). The LFE expressed activities of hydrolytic enzymes (amylase, cellulase, pectinase, protease), but SLE did not express. The contents of acetic acid, citric acid, and malic acid of SLE were higher than those of LFE, but lactic acid content of LFE was higher than that of SLE. The main free sugars of SLE were glucose (200.93 mg/g), fructose (236.32 mg/g), and sucrose (18.41 mg/g), but LFE did not detect all free sugars. The contents of polyphenol, anthocyanin, and piperidine alkaloid of LFE were higher than those of SLE. ${\alpha}$-Glycosidase activities were inhibited 3.4% and 16.2% by SLE and LFE. These results suggest that lactic acid fermentation extraction is an effective method to increase the yield and contents of functional quality of mulberry leaves extract.