• Horticultural Science & Technology
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• v.29 no.5
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• pp.488-493
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• 2011

Callus culture initiation of strawberry (Fragaria${\times}$ananassa Duch.) was investigated at different Murashige and Skoog (MS) medium strengths, types and concentrations of plant growth regulators, and incorporating a cold pretreatment period to determine the optimal nutritional and environmental conditions. No high quality callus was induced on MS media without auxin regardless of medium strength. When 6-benzylaminopurine (BA) was combined with indole acetic acid (IAA), naphthalene acetic acid (NAA), and 2,4-dichlorophenoxyacetic acid (2,4-D), high quality callus were highly induced compared to medium supplemented with auxin alone. When $0.5mg{\cdot}L^{-1}$ BA was combined with IAA, NAA, and 2,4-D, high quality callus induction was more effective than the medium supplemented with the other BA concentrations. The best combination of auxin and cytokinin for high quality callus induction was $1.0mg{\cdot}L^{-1}$ NAA and $0.5mg{\cdot}L^{-1}$ BA. Although the differences in callus induction were not significant, high quality callus induction at half strength MS medium was more effective than at full strength medium. When $30g{\cdot}L^{-1}$ sucrose was added to the half strength MS medium, the rate of high quality callus induction increased. The optimum cold pretreatment temperature and period for high quality callus induction were $4^{\circ}C$ and 72 h, respectively. Regeneration rate of high quality callus increased in MS medium supplemented with thidiazuron.

• Journal of Plant Biotechnology
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• v.45 no.2
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• pp.90-101
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• 2018

Strawberry (Fragaria ${\times}$ ananassa) is a globally-cultivated and popular fruit crop, prized for its flavor and nutritional value. Sweetness, a key determinant of fruit quality, depends on the sugar composition and concentration. We selected eight strawberry cultivars based on the fruit soluble solids content to represent high and low sugar content groups. The average soluble solid content was $13.6^{\circ}Brix$ (Okmae, Geumsil, Aram, and Maehyang) and $2.9^{\circ}Brix$ (Missionary, Camino Real, Portola, and Gilgyung53), for the high and low sugar content groups, respectively. Sucrose was the main sugar in the cultivars with high sugar content, whereas fructose was the main component in the low sugar content cultivars. Fruit starch concentration ranged from $3.247{\pm}0.056$ to $3.850{\pm}0.055g/100g$, with a 12% higher concentration in the high sugar content cultivars. Additionally, we identified 41 sugar metabolism-related genes in Fragaria ${\times}$ ananassa and analyzed the relationship between their transcripts and the sugar accumulation in fruit. FaGPT1, FaTMT1, FaHXK1, FaPHS1, FaINVA-3, and FacxINV2-1 were highly expressed in the high sugar content cultivars, while FapGlcT, FaTMT2-1, FaPHS2-1, FaSUSY1-1, and FaSUSY1-2 were highly expressed in the low sugar content cultivars. In general, a greater number of genes encoding sugar transporters or involved in sugar synthesis were highly expressed in the high sugar content cultivars. Contrarily, genes involved in sugar degradation were preferentially transcribed in the low sugar content cultivars. Although gene expression was not perfectly proportional to sugar content or concentration, our analysis of the genes involved in sugar metabolism and accumulation in strawberries provides a framework for further studies and for the subsequent engineering of sugar metabolism to enhance fruit quality.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.10
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• pp.1518-1524
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• 2016

This study was performed to minimize quality degradation of concentrated strawberry puree after $90^{\circ}C$ for 5 min by heat treatment with citric acid (CA) and acidic sodium metaphosphate (ASM) as pH modifiers. The highest color value was 1% CA+1% ASM (13.027), followed by 1% CA (9.539) and control (6.905). Anthocyanin contents were also 1% CA+1% ASM (3.049 mg/100 g), 1% CA (1.140 mg/100 g), and control (0.757 mg/100 g) in sequence. The DPPH radical scavenging activities of control, 1% CA, and 1% CA+1% ASM were 58.148, 72.638, and 83.736%, respectively. The color values, anthocyanin contents, and DPPH radical scavenging activities were significantly different at P<0.05 between control and 1% CA+1% ASM treatment. For the results of overall preference for hedonic test, there was no significant difference at P>0.05 among the three samples. During heat treatment, quality degradation of concentrated strawberry puree was reduced by 1% CA+1% ASM treatment, which is expected for new acidulants.

• Journal of Environmental Science International
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• v.27 no.10
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• pp.821-829
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• 2018

This study was conducted to examine the influence of Light-Emitting Diode (LED) light quality in urban agricultural plant factories on the growth and development of Seolhyang strawberry daughter plants in order to improve the efficiency of daughter plant growth and urban agriculture. LED light quality by demonstrated that above-ground growth and development were greatest for daughter plant 2. Daughter plant 1 showed the next highest growth and development, followed by daughter plant 3. Among the different qualities of LED light, the stem was thickest and growth rate of leaves was highest for R + B III (LED quality: red 660 nm + blue 450 nm/photosynthetic photon flux density (PPFD): $241-243{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) and lowest for R (red $660nm/115-117{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$). Plant height, leaf width, petiole length, and the leaf growth rate were highest for W (white fluorescent lamp/$241-243{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) and lowest for R + B I (red 660nm+blue 450nm/$80-82{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$). For above-ground growth and development, as the plants surpassed the seedling age, mixed light (red + blue), rather than monochromatic light (red or blue), and higher PPFD values tended to increase development. Regarding the quality of the LED light, daughter plant 2 showed the highest chlorophyll content, followed by daughter plant 1, and daughter plant 3 showed the least chlorophyll content. When the wavelength was monochromatic, chlorophyll content increased, compared to that when PPFD values were increased. Mixed light vitality was highest in daughter plant 2, followed by 1, and 3, showed increased photosynthesis when PPFD values were high with mixed light, in contrast to the results observed for chlorophyll content.

• The Korean Journal of Food And Nutrition
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• v.21 no.4
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• pp.499-509
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• 2008

The purpose of this study was to investigate the changes in physicochemical and sensory properties of raw fruits during washing and chlorine treatments. Strawberry and banana were pre-prepared at different concentration of chlorinated water(0 ppm, 50 ppm and 100 ppm), immersion time(3 min and 5 min), and number of post-rinsing(1 time, 2 times and 3 times). The physicochemical properties such as pH, sugar contents, residual chlorine contents, color values and hardness of the fruits were analyzed, and the sensory quality were evaluated throughout the sterilization treatment process. After washing strawberry with 100 ppm chlorinated water and 3 times of post-rinsing, pH and residual chlorine contents were showed a little difference, while sugar contents, hardness, and color values(L, a and b) were reduced. In case of banana, pH, sugar contents and residual chlorine contents were not affected, and hardness and L color value were reduced. However, a and b color values of banana were gradually increased as the development of brown discoloration. Sensory properties of the samples were affected by the chlorine sterilization treatment. In overall acceptance, strawberry and banana treated with 100 ppm chlorinated water showed the lowest scores among treatments. Therefore it could be suggested that the application of 50 ppm chlorinated water for $3{\sim}5$ minutes with over 3 times of post-rinsing was the effective pre-preparation method without affecting the quality of the fruits.

• Korean Journal of Agricultural Science
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• v.41 no.1
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• pp.9-16
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• 2014

This experiment was conducted to examine the effects of a short-term treatment of high pressure $CO_2$ on shelf-life of strawberry fruit. A short-term treatment (12 hr) of 100% $CO_2$ resulted in the increase of fruit firmness up to 71.9% compared to that at harvest. The firmness of $CO_2$ treated fruit remained a significantly higher than that of control (air) up to 15 days. The alteration of pectic polymers was observed by $CO_2$ treatment such as an increase of EDTA soluble pectins and decrease of water soluble ones. The $CO_2$ treatment resulted in the increase of total amount of wall bound calcium. Pectate lyase activity, an important agent of strawberry fruit softening, was also significantly reduced by $CO_2$ treatment. Contents of soluble solids and acids of $CO_2$ treated fruit were higher than those of control fruit. Short-term treatment of high pressure $CO_2$ affected shelf-life through firmness increase whereas the visual quality and decay incidence of strawberry fruit were not affected.

• The Korean Journal of Pesticide Science
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• v.19 no.3
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• pp.295-300
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• 2015

Currently, amount of export strawberry has been continuously increased to ship many south Asia countries, including Hong Kong and Singapore. In the distribution process, significant damage to the quality has been caused depending on the environmental conditions. Gray mold disease caused by Botrytis cinerea has been known as major damage to the export strawberry, and the disease was caused during shipping and distribution to the final consumers. This study was performed to assess the relationship between pathogen density in packing shed and disease incidence of gray mold during storage period. Maximum gray mold disease incidence in storage period was up to 16% with low temperature condition ($4^{\circ}C$). At room temperature condition, the disease incidence reached up to 100% even densities of the pathogen spore were recorded relatively low in the packing shed. As results of the study, the correlation between pathogen density in the air and disease occurrence clearly clarified.

• Food Science and Preservation
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• v.13 no.1
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• pp.13-17
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• 2006

The strawberry was dipped into $1\%\;CaCl_2$ solution at $20^{\circ}C\;and\;45^{\circ}C$ for 15min. respectively, and then packaged with or without PE film (thickness: 0.011mm) before putting into the cold storage at $5^{\circ}C$. The results showed the lowest rate of rot incidence and the highest firmness with higher Vitamin C content and the best superficial appearance in the treatment of $CaCl_2$ dipping at $45^{\circ}C$ with packaging. It also showed lower pH and higher titratable acidity in the treatment However, no significant difference of SSC was found among various treatments. The results suggested that the combination of postharvest calcium dipping and packaging could result in more effective preservation for strawberry compared with the individual treatment.

• Food Science and Preservation
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• v.23 no.1
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• pp.12-19
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• 2016

This study was conducted to determine $CO_2$ treatment condition to extend the shelf-life of 'Seolhyang' strawberry. Fresh strawberries with red color on 80% of the fruit surface were harvested. The samples at two different stages (on the $1^{st}$ and $3^{rd}$ day after harvest) were placed in a gas-tight chamber with 0, 5, 15, or 30% $CO_2$ concentration for 3 hours at $4^{\circ}C$. Then, the strawberry samples were immediately packaged in a PET tray and stored at $4^{\circ}C$. The carbon dioxide treatment was effective in maintaining the quality of 'Seolhyang' strawberries treated on the $1^{st}$ day after harvest. These samples had higher firmness, lower redness, softening index, and decay rate compared to samples treated on the $3^{rd}$ day after harvest. Treatment with both 15 and 30% of $CO_2$ concentration on the $1^{st}$ day after harvest induced an increase of firmness of 'Seolhyang' strawberry after the treatment. Samples treated with 15 and 30% $CO_2$ the $1^{st}$ day after harvest maintained quality for 10 days. However, samples treated with $CO_2$ on the $3^{rd}$ day after harvest lost marketability at 10 days of storage. At the atmosphere containing 30% $CO_2$ on the $1^{st}$ day after harvest was most effective in reducing decay rate and fruit softening, and maintaining bright red color of strawberries among different $CO_2$ concentrations. Therefore, a 30% $CO_2$ treatment within one day after harvest can be a practical postharvest technology to extend shelf-life of 'Seolhyang' strawberry.

• Proceedings of the Korean Society of Crop Science Conference
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• 1986.06a
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• pp.114-115
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• 1986