• Preventive Nutrition and Food Science
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• v.15 no.2
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• pp.152-158
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• 2010

This study was designed to determine the best cultivar of kohlrabi for making pickles among KM-1 (Worldcol), KM-2 (Bejo), KM-3 (Takii), and KM-4 (Monsanto) cultivars. The initial pH of pickles was different in all cultivars; however, they all had a pH in the range of 3.81~3.86 after 28 days of storage. The pickles made from KM-4 had the lowest acidity, while there was no significant difference in acidity among the KM-1, KM-2, and KM-3 pickles. The salinity of all kohlrabi pickles was consistent during the storage period. The changes of color values were accelerated in the following order: KM-4>KM-1>KM-2>KM-3. Though kohlrabi pickles were non-fermented, the change in reducing sugar contents was similar to that of a fermented pickle. The highest value of reducing sugar content was found in pickles made with KM-4. In all cases, the firmness of the pickle decreased as time of storage increased. On the initial day, KM-4 pickle showed the highest firmness with 807.4 g. KM-4 also showed the highest firmness on the 28th day of storage with 602.3 g. In sensory evaluation, the KM-4 pickle exhibited the highest texture (hardness) among the pickles. The pickle made with the KM-4 cultivar showed relatively higher firmness of texture than other cultivars, suggesting that KM-4 could be utilized in other kinds of processed foods, in addition to being pickled.

• Preventive Nutrition and Food Science
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• v.19 no.4
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• pp.281-290
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• 2014

The aim of the present study was to evaluate the anti-diabetic, anti-inflammatory, antioxidant potential, and total phenolic content (TPC) of green and red kohlrabi cultivars. Anti-diabetic and anti-inflammatory activities were evaluated via protein tyrosine phosphatase (PTP1B) and rat lens aldose reductase inhibitory assays and cell-based lipopolysaccharide (LPS)-induced nitric oxide (NO) inhibitory assays in RAW 264.7 murine macrophages. In addition, scavenging assays using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical, and peroxynitrite ($ONOO^-$) were used to evaluate antioxidant potential and TPC was selected to assess phytochemical characteristics. Between the two kohlrabi cultivars, red kohlrabi (RK) had two times more TPC than green kohlrabi (GK) and showed significant antioxidant effects in DPPH, ABTS, and $ONOO^-$ scavenging assays. Likewise, methanol (MeOH) extracts of RK and GK inhibited LPS-induced NO production in a dose dependent manner that was further clarified by suppression of iNOS and COX-2 protein production. The MeOH extracts of RK and GK exhibited potent inhibitory activities against PTP1B with the corresponding $IC_{50}$ values of $207{\pm}3.48$ and $287{\pm}3.22{\mu}g/mL$, respectively. Interestingly, the RK MeOH extract exhibited significantly stronger anti-inflammatory, anti-diabetic, and antioxidant effects than that of GK MeOH extract. As a result, our study establishes that RK extract with a higher TPC might be useful as a potent anti-diabetic, antioxidant, and anti-inflammatory agent.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.297-300
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• 2017

Plant factory can control artificially the environments for crop cultivation, so they can produce high quality agricultural products all year round. This study was carried to select suitable kohlrabi cultivar for hydroponics in a closed-type plant factory system. We used three cultivars of red kohlrabi, 'Asac kohl', 'Kolibri', and 'Purple king' as plant materials. The artificial light source was LED light, light intensity and photoperiod were $249{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ and 12/12 hours (day/night period), respectively. Hydroponic cultivation type was used circulating deep flow technique. At 43 days after transplanting, fresh weight of whole plant and tuber and leaf area were not significantly different among cultivars. Shoot dry weight and tuber dry weight were highest in 'Asac kohl' cultivar, and number of leaves was highest in 'Purple king' cultivar. Sugar content and yield were highest in 'Asac kohl' cultivar. Considering the growth and marketable yields, 'Asac kohl' was the optimal kohlrabi cultivar for hydroponic cultivation in a closed-type plant factory system.