• Journal of Adhesion and Interface
• /
• v.13 no.1
• /
• pp.1-8
• /
• 2012

The effect of the grafting ratio on the mechanical property and adhesion property of the grafted EPDM modified with methacrylic acid (MA) was investigated. The storage modulus of MA-grafted EPDM was maintained higher than that of cross-linked EPDM vulcanizate by sulfur, but it was observed that the storage modulus was decreased at elevated temperature because of the weakened secondary bonding. When the functional group for hydrogen bonding was introduced in EPDM, it had excellent mechanical properties by the aggregate between grafted EPDM molecules and crystallinity of MA. The bonding strength between EPDM and other rubbers was very low because EPDM has nonpolar property and low molecular interaction to others. The bonding strength was increased as increasing grafting ratio and it was excellent enough to break the rubber during the peel test when the grafting ratio was more than 10%.

• Journal of Bio-Environment Control
• /
• v.29 no.3
• /
• pp.239-244
• /
• 2020

Effect of 6kg large unit with the carton box (20% open ratio) and MA box (10,000cc·m^-2·day^-1·atm^-1 oxygen transmission rates modified atmosphere package), and the 100g small unit with MA film on asparagus sensory quality were evaluated. The CO₂ concentration depended largely on the packing unit and maintained at around 3% in small MA packages, whereas in the MA box increased to 12%. Ethylene concentration rapidly increased until after 3 days of storage in MA packages and then decreased to maintain 5μL·L^-1. Unrelated to the unit size, the lower weight loss was obtained in MA packages. A significant difference in visual quality was shown since the 15th day, the best and worst were the MA box and small MA package on the finish day. Off-odor was the highest in small MA packages and the lowest in the carton box (< 3.0). Although there was no significant difference in firmness among all treatments, the packages showed the highest firmness in tips and stems, respectively. The sugar content and hue angle decreased during storage, but there was no statistical difference in all treatments. EL was lowest and highest in small MA package and carton box, respectively. On the 10th day, the total aerobic bacteria was lowest in small MA packages, but no significant difference on the 20th day. E. coli was not found in all treatments on the 10th day, while it was the lowest in the MA box on the 20th day. The mold and yeast were not observed during the whole storage. Based on the above results, the carton box packaged with 10,000cc OTR film was more effective in maintaining the quality of green asparagus with the suitable CO₂ concentration for asparagus cold storage.

• Horticultural Science & Technology
• /
• v.19 no.1
• /
• pp.87-91
• /
• 2001

The aim of this study was to select the proper temperature for MA storage and to study the effect of sodium selenate ($Na_2SeO_4$) on storability of hydroponically grown sweet basil. Sweet basil was cultured with 1 fold using the nutrient solution developed by European Vegetable R & D Center in Belgium. Three-weeks before harvest, sodium selenate ($Na_2SeO_4$) was treated 2, 4, 6 and $8mg{\cdot}L^{-1}$ in the nutrient solution. Although electrolyte leakage of sweet basil was remarkably increased because of chilling injury at $5^{\circ}C$ MA storage, storage life was extended for three more days by selenium supplement. The weight loss was lower at $10^{\circ}C$ than at $5^{\circ}C$ and vitamin C content was higher at $10^{\circ}C$ than $5^{\circ}C$ storage treatment. Se treatment increased vitamin C content and decreased ion leakage in the plant. Accumulation of Se in the leaves of basil was increased with Se concentration of the nutrient solution. Se accumulation was $66{\mu}g{\cdot}g^{-1}$ dry mass at $2mg{\cdot}L^{-1}$ treatment and $422{\mu}g{\cdot}g^{-1}$ dry mass at $8mg{\cdot}L^{-1}$ treatment. The results suggest that storage at $10^{\circ}C$ is good for reduction of chilling injury and maintain marketability of basil. Less than $2mg{\cdot}L^{-1}$ sodium selenate treatment is acceptable for human health.

• Horticultural Science & Technology
• /
• v.19 no.4
• /
• pp.521-525
• /
• 2001

This study investigated the effects of conventional predrying and modified atmosphere (MA) on the head quality and storability of Chinese cabbage 'Norang' cultivar. Immediately after harvest, heads were predried for 2 days and MA stored in $50{\mu}m$ PE film packages at $4^{\circ}C$. MA packaging restrained Hunter L and b values of Chinese cabbage more effectively than non-packaging during storage at $4^{\circ}C$. But there was little change between the two treatments. Fresh weight decreased less in heads treated with predrying and MA than non-treatment during storage. Predried Chinese cabbage heads kept a high level of soluble solids in 4 weeks of storage, while non-packaging maintained high contents of soluble solids for 6 weeks of storage period. Chinese cabbage heads contained 7.0 mg/gFW glucose, 6.3 mg/gFW fructose, and 0.6 mg/gFW sucrose as major soluble sugars at harvest. The content of sugars decreased immediately after predrying and increased steadily after 2 weeks storage. It was found inappropriate to assess head quality of Chinese cabbage by investigating was investigated by Hunter a, firmness, dry matters content, pH, and soluble sugars after predrying and MA package. Marketability of Chinese cabbage was lost when heads were stored at room temperature in 2 weeks. It showed poor appearance of heads stored at $4^{\circ}C$ in 7 weeks. Decay occurred in Chinese cabbage stored in MA under excessive relative humidity. Predried head showed good appearance during storage at $4^{\circ}C$ for 7 weeks. As a result, Chinese cabbage heads can be successfully stored for at least 7 weeks with predrying and MA storage.

• Horticultural Science & Technology
• /
• v.28 no.6
• /
• pp.980-984
• /
• 2010

Research regarding respiration rate, off-flavor related material and freshness maintenance effect of active MA mini-packaging on perilla leaves has been carried in this study. Respiration rate was highly maintained at high oxygen treatments ($CO_2:O_2:N_2$=0:30:70 and 0:50:50), higher than non-treatment and low oxygen treatments (6:2:92, 0:10:90) during the storage period, and ethylene production was relatively higher. However, off-flavor related materials, acetaldehyde and ethanol production was noticeably low. Weight losses of non-treatment and low-oxygen treatment were about 1.8 and 1.4%, respectively. At the fifth day of storage there was no weight loss. Ascorbic acid content was 13.3 mg/100 g F.W. at the first day of storage. At the third day of storage non-treatment showed the lowest value of ascorbic acid, 8.8 mg/100 g F.W. Ascorbic acid content of active MA treatment gradually decreased without a striking difference as the storage day extended. Chlorophyll content was the lowest at the fifth day of storage with non-treatment, 47.5 (SPAD-502 unit) while the active MA treatment maintained high level of chlorophyll content, 53.0. Sensory evaluation (vision) showed that marketability gradually decreased but was maintained in high oxygen treatments (0:30:70 and 0:50:50), even at the fifth day of storage. Occurrence of off-flavor in non-treatment at the fifth day of storage was extremely low, 2.6; whereas high in high oxygen treatment, 3.4. Active MA packaging maintained freshness two more days at room temperature (about $27^{\circ}C$).

• Food Science and Preservation
• /
• v.11 no.4
• /
• pp.468-471
• /
• 2004

To investigate the effect of funcitional MA film 0.3 mm and control(non-pack) during 24 weeks of storage on 'Fuji' apple, the weight loss, firmness, a titratable acidity, soluble solid content(SSC $^{\circ}Brix$) and the rate of decay were measured. After 20 week storage, weight loss was $4.65\%$ in control, but $0.31\%$ in 0.03 mm funcitional MA film. The titratable acidity, soluble solid content and firmness were changed a little. The rate of decay was $4.2\%$ in control, and $1.1\%$ in funcitional MA film.

• Food Science and Preservation
• /
• v.1 no.1
• /
• pp.15-20
• /
• 1994

This experiment was carried out to select the optimum thickness of polyethylene film for the nonastringency of astringent persimmon fruits during modified atmosphere(MA) storage of Cheongdo Bansi kept at 0$^{\circ}C$. The experimental plots were divided into 5 plots by film thickness(0.08, 0.10, 0.12, 0.14 and 0.16mm). The experimental items were the changes in concentration of CO2 and O2 in film brig, soluble tannin contents, loss of weight firmness and external appearance of fruits. The nonastringency of persimmon fruits can be achieved all groups excepting the 0.08mm film during MA storage. The sweet persimmon in film bag of 0.10 and 0.12mm maintained a high quality and firmness, but following the deastringency the fruits in 0.14 and 0.16mm developed off-color. The increasing of carbon dioxide level and decreasing of oxygen level in film bag created anaerobic condition at earth stage, and then it kept a constant level during stooge. According to film thickness the obvious difference in the change of soluble tannin contents external appearance and firmness were observed. It could be concluded that the optimum thickness of film for the desirable nonastringency on Cheongdo Bansi was 0.10mm.

• Horticultural Science & Technology
• /
• v.19 no.2
• /
• pp.174-178
• /
• 2001

Absorption potential of oak charcoal was estimated using simulated static and dynamic systems to establish a model for practical application of the charcoal in modified atmosphere (MA) packaging and during the storage of 'Fuji' apples. Practical MA packaging was performed using $60{\mu}m$ PE film zipper bags in which five apples were placed. Absorption potential of oak charcoal was $58.4{\mu}L/100g$ charcoal for ethylene and 583 mg/100 g charcoal for carbon dioxide. Effects of enclosing a 100 g-charcoal packet inside a MA package seemed not to last long enough for quality maintenance of 'Fuji' apples stored at $0^{\circ}C$ for three months. During extended storage, ethylene and $CO_2$ levels were not significantly reduced by charcoal treatment. Nevertheless, absorption of carbon dioxide appeared to alleviate the incidence of $CO_2$-related internal browning disorder. Modelling study of practical storage and marketing procedure indicates that 0.19 kg charcoal/day is required to offset $CO_2$ production from 15 kg of apples at $0^{\circ}C$. The amount of charcoal should be increased to 3.10 kg/day if ethylene is a target gas. From the practical point of view, the results suggest that charcoal could be used only for small unit packages for a short period.

• Horticultural Science & Technology
• /
• v.35 no.3
• /
• pp.314-322
• /
• 2017

The aim of this study was to determine suitable oxygen transmission rate (OTR) films for modified atmosphere (MA) storage of asparagus spears (Asparagus officinalis L.), and to examine the related changes in asparagus spear quality. Asparagus spears were packed with 10,000, 20,000, 40,000, 70,000, and $100,000cc/m^2{\cdot}day{\cdot}atm$ OTR film treatments for MA storage, and perforated film (conventional storage) was used as the control. The fresh weight loss rate was less than 1% in all OTR film treatments but not in the control. In all OTR film treatments, ethylene content rapidly increased on the first day of storage, and gradually decreased thereafter to $2.0{\mu}L{\cdot}L^{-1}$ by the final storage day. In the 10,000 cc and 20,000 cc OTR film treatments, carbon dioxide content was maintained within the permissible range for asparagus spears under recommended controlled atmosphere (CA) and MA conditions (5-12%). The oxygen content was maintained between 12% and 20% in all OTR film treatments. Hue angles and total chlorophyll content were highest in the 10,000 cc OTR film treatment in both tips and stems. Visual quality was maintained at a saleable level only in the 10,000 cc OTR film treatment until the final storage day (25 days). Based on sensory evaluation, the least off-odor was detected in the 10,000 cc OTR film treatment, and the most in the control treatment. While the soluble solids content decreased with all film treatments, it was maintained at the highest level in the 10,000 cc OTR film treatment. Vitamin C content decreased with all film treatments during storage, but was maintained at higher levels in the 10,000, 20,000, and 40,000 cc OTR film treatments. The firmness of tips and stems increased with storage duration in all film treatments, stems were firmer under the perforated film, 10,000, and 20,000 cc OTR film treatments. Given these results, the 10,000 cc OTR film treatment is considered the most appropriate for MA asparagus spear storage since visual quality and soluble solids content were maintained, and fresh weight loss, vitamin C content, off-odor, and yellowing were suppressed during storage.

• Journal of Practical Agriculture & Fisheries Research
• /
• v.23 no.1
• /
• pp.67-80
• /
• 2021

We analyzed the effect of planting site (elevation: high, middle, low) and temperature condition of orchard on the frost injury occurrence and storage characteristics of persimmon (Diospyros kaki cv. 'Fuyu) fruits under an early fall frost at two orchards, Changwon (A) and Changnyeong (B), Gyeongsangnam-do Korea. Also, the fruits picked at Nov. 5 and Nov. 20 were MA stored to investigate the quality and chilling injury of fruits. On 2-way factor analysis, both planting elevation and orchard factor had not a significant effect on fruit characteristics (weight, firmness, soluble solid), while planting elevation factor did on the skin color (hunter 'a')(p<0.05). A fruit skin coloration at orchard A was faster than that at orchard B. At low elevation of orchard B, 2% fruits were frost injured at harvest season. On LDPE film MA storage with the fruits harvested at Nov. 5 and Nov. 20, the fruits at orchard A had higher fruit firmness than those of orchard B during storage. In addition, the 73% (orchard A) and 85%(orchard B) fruits harvested at Nov. 5 showed no chilling injury 80 days after storage. However, At harvest of Nov, 20 (after incidence of frost), only the 14% fruits of orchard B had no the chilling disorder 80 days after storage, even though 76% fruits at orchard A did.