• Microbiology and Biotechnology Letters
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• v.35 no.2
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• pp.135-141
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• 2007

To increase the consumer acceptability of yam and the shelf-life of fresh-cut yam, organic acid-treated fresh-cut yam was prepared. When uncontaminated fresh-cut yam was stored at $4^{\circ}C$ for 14 days after treatment with 1% (v/w) organic acids, the browning and microbial putrefaction of fresh-cut yam were inhibited by treatment of acetic acid or maleic acid, whereas treatment of citric acid and ascorbic acid, commonly used browning inhibitors in food industry, did not show apparent effects on the browning and putrefaction of yam. The Inhibitory effects of acetic acid or maleic acid were superior than those of NaOCl (100 ppm), hydrogen peroxide (100 ppm) or commercially available washing solution. Also, treatments of 1% acetic acid, or 1% maleic acid Into artificially-contaminated yam $(10^5\;CFU/g-yam)$ showed strong inhibition of browning and putrefaction during long term storage at $4^{\circ}C$. The growth inhibition test indicated that 0.1% is enough to inhibit the growth of psychrotrophic yam-putrefactive Pseudomonas sp., and treatment of 0.1% acetic acid, or 0.1% maleic acid inhibited the browning and microbial putrefaction of fresh-cut yam. Our results suggested long-term distribution of yam or other root crops products is possible by treatment of organic acid, such as acetic acid, combined with aseptic vacuum packaging technology.

• Microbiology and Biotechnology Letters
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• v.35 no.1
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• pp.66-72
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• 2007

Yam has been recognized as healthy food due to its various biological activities, such as anti-obesity, antimicrobial, anticancer and immune-stimulation activities. In this study, antibacterial activities of 800 more natural plant extracts against yam-putrefactive psychrotrophic bacterium, Pseudomonas rhodesiae YAM-12, were evaluated to select a natural preservative, which is useful to long-term storage of yam and fresh-cut production. Finally, the clove oil was selected, and applied for the production of yam fresh-cut. The 1% of clove oil treated fresh-cut showed minor color changes during 31 days storage at $4^{\circ}C$ and the microbial growth was not detected. When the artificially contaminated fresh cut by dipping with P. rhodesiae YAM-12 suspension for 3 min was treated 1% clove oil, the microbial growth was identified to $10^4$ CFU/g from $10^3$ CFU/g with minor color changes. Whereas, treatment of sterilized water, or 100 ppm NaOCl into artificially contaminated fresh cut showed severe putrefaction $(10^8\;CFU/g)$ and color changes. Considering the previous reports that clove oil has antimicrobial, antioxidation, and antithrombosis activity, the use of clove oil into the yam fresh cut will provide market safety and consumer acceptability by prevention of microbial putrefaction and its biological activity.

• Journal of Life Science
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• v.17 no.5 s.85
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• pp.652-657
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• 2007

To make functional fresh-cut yam using natural spices, the water or the methanol extract was prepared from different kinds of natural spices including ginger, wasabi, black pepper, mustard, cinnamon, chinese pepper, garlic, thyme, rosemary, chamomile, and peppermint. The extraction yields were varied as spice sources and extraction solvents used. Among the water extracts, peppermint extract showed strong antithrombosis activity with 26-folds extended thrombin time, and the $IC_{50}s$ of the extracts from cinnamon and rosemary were $61.3{\mu}g/ml\;and\;84.3{\mu}g/ml$ in DPPH scavenging assay, respectively. Whereas, the antimicrobial activity of all water extracts was ignorable. Among the methanol extracts, the extracts from thyme, ginger, and cinnamon showed antimicrobial activity against yam putrefactive bacteria. Strong antioxidative activity was found in the extracts from cinnamon and thyme. Based on these results, the functional fresh-cut yam was prepared using the water extract from peppermint or cinnamon. The antioxidative and antithrombin activities in the fresh-cut yam were maintained at $4^{\circ}C$ for 24 hr. Our results suggest that the natural spices could be applied to production of functional fresh-cut yam.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.21 no.3
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• pp.115-120
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• 2015

In this experiment, sliced yams (5 mm size) were used for research. Alcohol treatment and blanching treatment were used in this experiments. Color change, hardness, microorganism total count, and PPO activity of the packaged yam were measured. In result, colors of the treated yam were significantly changed in alcohol treatment with different concentration. 5% alcohol treatment is better than 10% alcohol treatment in browning inhibition of fresh-cut yam. But in blanching treatment, color change had no significant different. PPO activity of 1 min blanching packaged yam were decreased 50% and PPO activity of 5 min blanching packaged yam were decreased 85%. In the case of hardness were decreased in both experimental groups. especially 1 min, 3 min and 5 min blanching films, hardness were decreased more than 10 N. Also, both treatments are inhibited the growth of microorganisms effectively.

• Korean Journal of Plant Resources
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• v.8 no.2
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• pp.201-207
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• 1995

Chinese yam (Dioscorea Opposita Thanb) has been cultivated as medicinal crop and food. The experiment was carried out to determine the effect of tuber head origin and fertilizer application method on its agronomic characters of shoot and root tuber to get some imformation on its cultivation. The tuber head cultivated were cut from normal or branched root tuber. 37-28-32-2000 : N-P-K-Humus(Kg/10a) by dispersal but 30% N reduction of Con(RN) or strip application on the two-side of hill(SRN), were applied but N and K were given by the above method with the rate of 40% in March, 30% in June and 30% in July. Agronomic characteristics related to shoot and root tuber were measured and their relationship was analyzed. Tuber head origin had no effect on emergence rate, vine length, branch and node of vine, while emergence date of the tuber head from the normal root which showed the greatest emergence rate, vine length and node in Con treatment was earlier than the others. The tuber head from the normal root, furthermore, had greater length and diameter of root tuber harvested from the field and fresh weight per plant of per 10a compared to the tuber head from the branched root, whereas in both the normal and the branched tuber head RN had the worst result in the characters related to tuber yield except tuber diameter. The tuber head from the normal root produced heavier root tuber than that from the branched tuber and SRN had the best economic yield among the application methods, which resulted from production of less branched root tubers and their rate. In both the normal and the branched tuber head, moreover, yield per plant and economic yield were positively correlated to tuber length but negatively done to number. of branch of vine.