• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.2
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• pp.201-210
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• 2009

This study was undertaken to investigate the quality properties of yakchobugak as affected by lactic acid bacteria and waxy rice paste for improving palatability of yakchobugak of Agastache rugosa. Total sugar contents of lactic acid bacteria-fermenting waxy rice paste gelatinized at $90^{\circ}C$ were higher than that of $70^{\circ}C$. Reducing sugar contents were $2{\sim}5$ times higher in $70^{\circ}C$ waxy rice paste than in $90^{\circ}C$ waxy rice paste and increased as the fermentation progressed. Total acidity of waxy rice pastes gelatinized at $70^{\circ}C$ and fermented for 15 hours were $2.7{\sim}1.3$ times higher than at $90^{\circ}C$, and then Lactococcus lactis had the lowest total acidity during fermentation. Viscosity of fermented paste (VFP) were lower than those of raw paste. VFPs gelatinized at $90^{\circ}C$ were markedly higher than those at $70^{\circ}C$ over 28% concentration. In L. lactis and Lactobacillus plantarum, VFPs fermented for 15 hours were over $2{\sim}3$ times lower than those fermented for 40 hours. Hunter's color lightness (L) and yellowness (b) were decreased according to the elevation of gelatinization temperature and fermentation time. L. lactis and L. plantarum-producing waxy rice pastes were the uniform micell type with a large air-pore size and amorphous micell type with a small air-pore size, respectively. Based on these results, L. lactis was a lower lactic acid-producing bacteria as well as uniform air-pore distribution on waxy rice paste. It was found to be a good sourpaste-fermenting strain for enhancement of quality properties of yakchobugak, as revealed through viscosity, total acidity, Hunter's color b value and scanning electron micrographs.

• Food Science and Preservation
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• v.16 no.2
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• pp.266-275
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• 2009

To develop new high-quality Yakchobugak, features of Lactococcus lactis-fermented waxy rice paste after addition of some colored powdered agro-food products were investigated. Total and reducing sugars of waxy rice paste fermented by lactic acid bacteria were higher than those of control raw waxy rice paste. Total acidity gradually increased as powder concentration rose, being 1.02-1.56% and 0.96-1.87% in samples fermented with Cucurbita maxima and Capsicum annuum powders, respectively; these values were 3-4 times those in rice fermented with other powders. Fermented waxy rice paste viscosities were lower than those of non-fermented samples. The viscosities of samples fermented with Curcuma longa and Opuntia ficus powders were in the range $100-160{\times}10^4$ centipoise($mPa{\cdot}s$), and those of pastes fermented with Robus coreanus and Camellia sinensis extracts were under $40{\times}10^4mPa{\cdot}s$. Hunter color lightness(L) values decreased and yellowness(b) values rose after fermentation. Waxy rice paste fermented with Robus coreanus showed uniform particle size distribution, and many pores, by scanning electron micrography.

• Food Science and Preservation
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• v.16 no.3
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• pp.405-411
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• 2009

The manufacturing process and quality properties of Lactococcus lactis-fermented yakchobugak (LFY) containing some colored agro-food products were investigated to develop a good organoleptic bugak from the leaf of the medicinal herb. The de-oiling rate of LFY by centrifugation was 37.6%, which was significantly different to the 3.5% value obtained after standing and the 8.9% value obtained with the beating method (p<0.05). Reducing power (RS) increased with addition of increasing levels of ethanol extracts from agro-food powders. The RS of green tea extract-supplemented LFY had the highest value of 0.97 at $500{\mu}g/mL$, and this was significantly different to values obtained using other extracts (p<0.05). At 83.84%, the DPPH (2,2-diphenyl-1-picrylhydrazyl) free-radical scavenging activity of green tea extract-supplemented LFY was the greatest of all samples tested, followed by LFY with woolgeom at 39.48%, LFY with black rice at 28.45%, and LFY with bokbunja at 22.24% all ethanol extracts were added at $50{\mu}g/mL$ (p<0.05). Acid values of green tea and bokbunja LFYs stored in transparent PE bags at $60^{\circ}C$ for 7 days were 1.82% and 2.03%, respectively. Textural hardness values of LFYs were less than 250.62, except for LFYs with black rice and woolgeom, but these values increased $2{\sim}3$-fold after lactic acid fermentation. Carbohydrate and protein content of LFYs were in the ranges $58.95{\sim}64.63%$ and $7.50{\sim}8.68%$, respectively. Lipid and calorie contents of woolgeom LFY had the lowest values of 22.02% and 490 Kcal, respectively.