• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.67 no.3
• /
• pp.172-179
• /
• 2022

Sweet potato varieties with high fiber content in the storage root have poor texture when steamed or roasted. This study investigates the difference in fiber content among sweet potato varieties by soil and climate. The average fiber content of 'Hogammi', 'Sodammi', 'Pungwonmi', 'Danjami', and 'Jinyulmi' cultivars from the samples collected at farms in Haenam, Muan, and Unbong, Korea were 95.71, 66.73, 44.55, 40.55, and 38.53 mg/100g FW, respectively. There was no significant difference between site-specific conditions and varieties. Based on the degree of visual fibrousness, 'Hogammi' has an average of 3.6-4.0 with many thick stringy fibers. The fiber content of the 'Hogammi' cultivar was measured across 19 sites representing the main sweet potato growing regions of Korea. The fiber content was between 115.82 and 114.6 mg/100g in Haenam 2 and Boryeong 1, and 87.46 mg/100g in Hamyang. However, the fiber content at the remaining 16 sites was within the range of 94.63-108.52 mg/100g, although there were some site-level differences. The fiber content of the sweet potato storage roots were positively correlated with soil phosphorus (R² = 0.58^**), organic matter (R² = 0.52^*), and pH (R² = 0.51^*), which had a significance of 1% and 5%. The fiber content of sweet potato storage roots was found to have increased with increasing phosphorus content, organic matter and pH in the soil. However, there was no correlation with the amount of precipitation, days of precipitation and hours of sunshine with the fiber content of sweet potato at the selected sites.

• Microbiology and Biotechnology Letters
• /
• v.51 no.1
• /
• pp.83-92
• /
• 2023

In this study, bioconversion of rutin to quercetin was confirmed by the fermentation of Korean indigenous probiotics and tartary buckwheat. Based on whole genome sequencing of 17 probiotics species, α-rhamnosidase, related to bioconversion of isoquercetin (quercetin 3-β-D glucoside) from rutin, is identified in the genome of CBT BG7, LC5, LR5, LP3, LA1, and LGA1. β-Glucosidase, related to bioconversion of isoquercetin to quercetin, is identified in the genome of all 17 species. Among the 17 probiotics species, 6 probiotics including CBT BG7, LR5, LP3, LA1, LGA1 and ST3 performed the bioconversion of rutin to quercetin up to 21.5 ± 0.3% at 7 days after fermentation. The fermentation of each probiotics together with enzyme complex Cellulase KN^® was conducted to reduce the time of bioconversion. As a result, CBT LA1 which showed the highest yield of bioconversion of 21.5 ± 0.3% when the enzyme complex was not added showed high bioconversion yield of 84.6 ± 0.5% with adding the enzyme complex at 1 day after fermentation. In particular, CBT ST3 (96.2 ± 0.4%), SL6 (90.1 ± 1.4%) and LP3 (90.0 ± 0.4%) showed high yield of bioconversion more than 90%. In addition, such probiotics including high levels in quercetin indicated the inhibitory effects of NO production in LPS-induced RAW264.7 cells. In this study, we confirmed that the fermentation of Korean indigenous probiotics and enzyme complex together with roasted tartary buckwheat increased the content of quercetin and reduced the time of bioconversion of rutin to quercetin which is a bioactive compound related to anti-inflammatory, antioxidants, anti-obesity, and anti-diabetes.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.68 no.1
• /
• pp.20-26
• /
• 2023

Fiber content in the storage roots of sweetpotato varies between different varieties. For examples, the high fiber content of certain types has a poor texture when steamed or roasted. This study was conducted to evaluate the optimal sieve mesh size for separating fibers, the chemical composition of fibers and differences in fiber content among different varieties. We found that the separated fiber content (dry weight) of mashed and steamed sweetpotato was higher after washing three times (143.3 mg/100 g) compared with that washed five times (128.4 mg/100 g). The Hogammi variety remained 85.9% of total fiber content at 10 mesh (2,000 ㎛) and 9.6% of total fiber content at 30 mesh (600 ㎛), and Jinyulmi remained 74.9 and 16.7% of total fiber content , respectively. Therefore, a 30 mesh sieve was considered the most suitable for fiber separation. Among the 10 studied cultivars, Jinhongmi showed the lowest amount of fiber (24.8 mg/100 g) and Hogammi had the highest amount (111.4 mg/100 g), which was 4.5 times larger than that of Jinhongmi. Cellulose, hemicellulose and lignin content of separated fibers showed no difference between the viscous-type Hogammi and powdery-type Jinyulmi varieties, with averages of 32.5, 22.3 and 29.6%, respectively. Correlation results using the Image J program showed a significant correlation between the distribution of the stained area and the fiber content (R = 0.74, p < 0.05). Staining distribution differed among varieties, suggesting that a simple fiber content test could be performed using the staining method on raw sweetpotato. These results provide useful information to help inform farmers on the fiber content of different sweetpotato varieties.

• Journal of the Korean Society of Food Culture
• /
• v.21 no.6
• /
• pp.653-660
• /
• 2006

Some quality characteristics of tofu prepared with cuttlefish ink were investigated to study the effects of various of coagulants. Each concentration of coagulant was determined as 0.2% of GDL, 0.3# of $MgCl_2$, 1%^ of $CaCl_2$, 1.5% of $CaSO_4$ and 0.6% D-gluconic acid calcium by pre-experiment. Also, the optimum concentration of added cuttlefish ink was chosen as 3%(diluted in twenty times). The yield of inky tofu prepared with GDL as coagulant was the highest. According to prepared with $MgCl_2$ was the highest. The result of microstructure was examined by SEM, the particles of inky tofu coagulated with GDL and D-gluconic acid calcium were small and uniformity. In overall acceptability of sensory properties, inky tofu coagulated with GDL was the highest in score. In the color of inky tofu, L value and a value were the highest coagulated with GDL, but that coagulated with $CaCl_2$ had the highest b value. In the texture properties of inky tofu, hardness, gumminess and brittleness were the highest coagulated with D-gluconic acid calcium. A positive correlation was observed between the pH of tofu whey and acidity. Sensory properties of roasted nutty flavor, hardness, cohesiveness and springiness were positively correlated with the acceptability.

• Food Science and Preservation
• /
• v.30 no.4
• /
• pp.703-715
• /
• 2023

This study was conducted to investigate the fermentation characteristics and anti-obesity effects of acetic acid fermentation products of coffee wine. The live cell counts, soluble solids, pH and total acidity of the acetic acid unfermented coffee wine (AUFCW; day 0, before fermentation) were 6.35 log CFU/mL, 8.10 °Brix, 3.88, and 1.29%, respectively, while the acetic acid fermented coffee wine (AFCW; day 15, after fermentation) were 4.40 log CFU/mL, 8.57 °Brix, 3.07, and 7.45%, respectively. Pancreatic lipase inhibitory activity tended to increase as the acetic acid fermentation period increased. The anti-obesity effects of AFCW on 3T3-L1 cells, which was induced by MDI, were evaluated based on the lipid accumulation rate, leptin expression, and fat production-related gene expression (PPAR-γ and SREBP-1c) at the mRNA level. In the case of AFCW, the lipid accumulation rate and leptin expression were decreased to 69.37% and 50.20% at a concentration of 200 ㎍/mL, respectively, and the expression levels of PPAR-γ and SREBP-1c at the mRNA level were decreased to 79.89% and 48.81%, respectively. These results indicate that anti-obesity effect of acetic acid fermentation products could be increased by acetic acid fermentation of coffee wine.

• Journal of Food Hygiene and Safety
• /
• v.27 no.3
• /
• pp.233-246
• /
• 2012

In this study, we investigated the applicability of the photostimulated luminescence(PSL), thermoluminescence(TL) and electron spin resonance(ESR) methods for various foods which are not allowed to be irradiated in Korea. All 15 foods including sesame, almond, peanut, cocoa powder etc. were analyzed. Samples were irradiated at 1~10 kGy using a $^{60}Co$ gamma-ray irradiator. In PSL study, the photon counts of all the unirradiated samples showed negative(lower than 700). The photon counts irradiated(1 kGy) dried shrimp, roasted peanut and seasoned peanut showed positive(higher than 5,000) and the other samples were negative or intermediate(> 700 and < 5,000). In TL analysis, results showed that it is possible to apply TL method to all foods containing minerals. In ESR measurements, the ESR signal(single-line) intensity of irradiated foods was higher than non-irradiated foods. In particular, the specific ESR signals of irradiation-induced crystalline sugar, cellulose and bone radical were detected in dried plum, raisin, dried cherry, mango(dried, frozen), rambutan, cocoa(powder), cinnamon, parsley, carrot, broccoli, dried arrow squid, dried pollack and dried shrimp. According to the results, PSL, TL and ESR methods were successfully applied to detect the irradiated foods because TL method is not able to detect the irradiated foods rarely composed of minerals. ESR is also a difficult method to detect the changes of ESR signal patterns of food. It is concluded that TL analysis or ESR assay is suitable for detection of irradiated samples and a combined method is recommendable for enhancing the reliability of detection results.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.17 no.5
• /
• pp.353-360
• /
• 1984

As an effort to expand the utilization of mackerel which has been thought disadvantageous to processors due to the defects in bloody dark color of meat, high content of lipid, and low stability of protein, and to develope a new type of product, so called, preservative fish meat paste, the processing method was studied in which dielectric heating was applied by means of cooking, pasteurization, dehydration, and control of water activity. The principle of this method is based on that dielectric heating can initiate a rapid dispersion or displacement of moisture in the meat tissue so that the level of water acivity can be controlled by dehydration with hot air meanwhile the product is cooked, pasteurized, and texturized. And the product is finally heated with electric heaters and vacuum sealed to stabilize water activity and storage stability. In present paper, a formula for preparing the fish meat-stach paste, the conditions of dielectric heating and dehydration, shape and size of the product, and other parameters were tested to optimize the process operation. A formula of the fish meat-starch paste to provide proper textural properties and water activity was $10\%$ starch, $1.5\%$ salt, $3\%$ soybean, $0.6\%$ MSG, $2\%$ sucrose, and $3\%$ sorbitol against the weight of fish meat. A proper shape and size of the product to avoid foaming and case hardening during heating was sliced disc of 8 cm $diameter{\times}0.8$ cm thickness or $10{\times}10$ cm square plate with 1.0 cm thickness. The disc shape was recommended because it resulted more uniform heating, minimum foaming and case hardening. And it was also advantageous that disc was simply provided when the fish meat disc was stuffed in the same, solidified in boiling water for 2 to 3 minutes, and sliced. Condition of dielectric heating was critical to decide the levels of sterility, water activity, and textural property of the product. The temperature at the center of the meat disc slices was raised up to $95^{\circ}C$ in 1.5 minutes so that continuous exposure to microwave caused expanded tissue and hardening ending up with a higher water content. Heating for 5 to 6 minutes was adequate to yield the final water activity of 0.86 to 0.83(35 to $40\%$ moisture). It is important, however, that heating had to be done periodically, for instance, in the manner of 2.0, 1.5, 1.5, and 1.0 minute to give enough time to displace or evaporate moisture from the meat tissue. The product was dehydrated for 2 to 3 minutes by hot air of $60^{\circ}C$, 3 to 5m/sec and finally exposed to electric heaters for 5 to 6 minutes until the surface was roasted deep brown. These conditions of heating and dehydration resulted in a complete reduction of total plate count from an initial count of $5.3{\times}10^6/g$ to less than $3{\times}10^2/g$. General composition of the product was $40.1\%$ moisture, $20.8\%$ protein, $17.4\%$ lipid, $16.2\%$ carbohydrate, and $5.5\%$ ash. Textural properties revealed folding test AA, hardness 42, cohesiveness 0.53, toughness 4.6, and elasticity 0.8.