• Food Science and Preservation
• /
• v.16 no.6
• /
• pp.797-803
• /
• 2009

The effects of drying methods on the browning and moisture sorption characteristics of Rubus coreanus were studied. Fruits were steamed for 5 min at $100^{\circ}C$, dried by sun drying, infrared drying, or freeze drying, and powdered to a size of 20 mesh. Color values were measured and equilibrium moisture contents (EMC) were determined at $20^{\circ}C$, over a range of water activity ($a_w$) from 0.11 to 0.90. The browning indices $L^*$ and $a^*$ values were higher and lower, respectively, in freeze-dried Rubus coreanus compared with other samples. The $b^*$ value was greatest in freeze-dried Rubus coreanus. EMC tended to increase with increasing $a_w$ values, and a particularly sharp increment was observed above 0.75 $a_w$. The EMC of freeze-dried Rubus coreanus was significantly higher compared with the EMC of sun-dried and infrared-dried fruit at constant aw. The moisture sorption isotherms showed a typical sigmoid shape, and the Halsey, Kuhn, and Oswin models were the best fits for the sun-dried, infrared-dried, and freeze-dried powder isotherms, respectively. With respect to monolayer moisture content, the Guggenheim-Anderson-Boer (GAB) equation showed that the various drying methods yielded very different results, with monolayer moisture contents of 0.005 g $H_2O/g$ dry solid in infrared-dried and 0.019 g $H_2O/g$ dry solid in sun- and freeze-dried powders, respectively. These results indicate that the drying method affects the browning and moisture sorption characteristics of Rubus coreanus.

• Food Science and Preservation
• /
• v.5 no.1
• /
• pp.23-28
• /
• 1998

The objective of this study was to investigate the methods of quality maintenance using modified atmosphere packaging with various quality preservatives at ambient and low temperatures. Ethylene(<1.0ppm) accumulated during modified atmosphere storage of Chinese cabbage using polyethylene film(60$\mu\textrm{m}$) caused quality deterioration such as yellowing and abscission. The addition of potassium permanganate reduced ethylene level and thus extended storage life of l00% at 20$^{\circ}C$ and 140% at 0$^{\circ}C$. To establish the storage conditions of minimally processed sit and vegetables, the experiment was conducted with various quality preservatives and packaging materials. Ceramic film(Zeolite 7%, 60$\mu\textrm{m}$) showed increasing storage life of 50%, reducing total microbial counts of 50% and keeping high appearance quality of minimally processed pears stored at 20$^{\circ}C$ and 0$^{\circ}C$. Minimally processed Chinese cabbage treated with l% CaCl2 at 20$^{\circ}C$, and 1% CaCl2 and 1% NaCl at 0$^{\circ}C$ has a longer storage life of 90% with good maketable quality. Treatment of 1% NaCl for cut Asian penis appeared increased storage life of 100%, decreased cut surface browning and the best overall acceptability by a sensory panel.

• Agricultural and Biosystems Engineering
• /
• v.4 no.1
• /
• pp.1-7
• /
• 2003

Internal defects such as browning of the flesh and blackening and rot of the ovary of pear can be easily developed because of the inadequate environmental conditions during the storage and distribution of fruit. The quality assurance system for the agricultural product is to be settled in Korea. All defected agricultural products should be excluded prior to the distribution to enhance the commercial values. However, early stage on-line defect detection of agricultural product is very difficult and even more difficult in a case of the internal defects. The goal of this research is to develop a system that can detect and classify internal defects of agricultural produce on-line using VIS/NIR transmittance spectroscopy. And Shingo pear, which is one of the famous species of Korean pear, was used for the experiment. Soft independence modeling of class analogy (SIMCA) algorithm was employed to analyze the transmittance spectroscopic data qualitatively. On-line classification system was constructed and classification model was developed and validated. As a result, the correct classification rate (CCR) using the developed classification model was 96.1 ％.

• Food Science and Preservation
• /
• v.4 no.2
• /
• pp.147-153
• /
• 1997

Oriental melon has been increased in production amount, but its processed food was not made in spite of the fact that shelf-life of the fresh fruit is short. This study was carried out to develop a dried product with no use sulfur treatment. Fresh melons were peeled, cut into 6 pieces, and soaked to the following pretreatments soaking in sugar syrup(SS), sodium chloride(SC), ascorbic acid(AA) and sodium polyphosphate(SP). After preatreatments the melon pieces were dried by hot air drying at 5$0^{\circ}C$ for 9 and 12 hours, and the dried melons were air blown at $25^{\circ}C$ for 1 day. The dried samples were evaluated for moisture content, texture, rotor, and sensory quality. The moisture content of dried melons soaked in SS and SC were lower than those that were soaked in AA and SP after hot air drying. The melons dried for 12 hours were high in hardness, gumminess, chewness and adhesiveness and excellent in sensory evaluation compared to 9 hours. The "L" value of SS was higher and the "a" value was lower in Hunter color. And SS treatment inhibited browning of the dried melon and improved sensory characteristics in color, flavor, texture and taste. Sucrose concentration had no significant effect on color, hardness and sensory score in banal product. The combination of SS with SP represented a highly effective antibrowning treatment for the dried melon and the product was kept in good color for 3 months at room temperature.at room temperature.

• Food Science and Biotechnology
• /
• v.15 no.4
• /
• pp.529-533
• /
• 2006

To produce fresh-cut fruit products of high quality, the combined effects of postharvest calcium and heat treatment on Tsugaru apple were examined. Whole fruits were treated for 20 min at three different conditions: dipping in 3% $CaCl_2$ solution at $45^{\circ}C$ or ambient temperature, or in heated water at $45^{\circ}C$. The calcium content of the apples dipped in $CaCl_2$ solution at $45^{\circ}C$ was higher than that of the control and the non-heated calcium dipping. The fruits with calcium and heat treatment showed the same pattern of respiration rates as the control did during storage. The browning degree of the apple slices increased to approximately 3% after one-day storage, but no significant difference was observed between the treated and untreated apples. The fruits with $CaCl_2$ solution dipping at $45^{\circ}C$ had higher firmness than those with calcium dipping or heat treatment alone.

• Korean Journal of Food Science and Technology
• /
• v.27 no.6
• /
• pp.891-896
• /
• 1995

In order to screen natural inhibitor of tyrosinase which catalyzes an enzymatic browning of some foods and in vivo synthesis of melanin, inhibitory effect of 129 edible plants and 15 chemical compounds on the in vivo melanin synthesis by mushroom tyrosinase was analyzed. Among leafy vegetables tested, radish bud, red chicory, Shepherd's purse and small green onion were found to have more than 50% tyrosinase inhibition effect in the descending order. Chinese radish and garlic in root vegetables, and nameko, shiitake and oyster mushroom in mushrooms, and teas showed also more than 50% inhibition effect. Among fruit vegetables tested, red pepper, Chinese quince and avocado were found to have more than 50% tyrosinase inhibition effect, while fruits generally showed low inhibitory effect. Medicinal plants which inhibit tyrosinase more than 50% were mume fructus>cinamomi ramulus>rubi fructus>mori cortex>biotae orientalis folium>puerariae radix, and herbs with more than 50% inhibitory effect were allspice>clove>mustard. In some chemical compounds tested, 4-hexylresorcinol, L-cysteine, glutathione, sodium bisulfite and kojic acid showed powerful inhibition effect on mushroom tyrosinase.

• Korean Journal of Plant Resources
• /
• v.27 no.1
• /
• pp.72-79
• /
• 2014

This study was investigated the changes in quality of peeled chestnut according to peeling method, including abrasion and knife, and 3 kinds of storage temperatures. The weight loss rate of peeled chestnut during storage period was observed in all treatment groups, peeling methods showed no difference of the loss. However, the moisture content of peeled chestnut during storage in all treatments showed a tendency to decrease. Moisture content of the abrasion peeled chestnut in all treatments was higher than that of the knife peeled chestnut. In the case of a, b, and ${\Delta}E$ value of peeled chestnut chromaticity increased during storage in all treatments, whereas, L values decreased during storage. But, browning of abrasion peeled chestnut was higher than that of the knife peeled chestnut. The hardness of the abrasion and knife peeled chestnuts were the highest in $-1^{\circ}C$ storage, soluble solid content was decreased with storage time in all treatments, but showed a tendency to increase within 24 days. Palatability and texture of peeled chestnuts decreased in all treatments during storage period, 15 days after storage decreased rapidly. Thus, results showed that peeled chestnuts stored at $4^{\circ}C$ and $2^{\circ}C$ were rapidly decreased in the quality after 15 days, whereas, peeled chestnuts stored at $-1^{\circ}C$ slowly decrease in the fruit quality. It can be recommended that chestnut in vacuum film is good to maintain at $-1^{\circ}C$ storage for 15 days. Also, if we can reduce the browning of abrasion peeled chestnut, we will produce peeled chestnut of high quality.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.46 no.1
• /
• pp.140-145
• /
• 2017

Pinus koraiensis cone (PKC) extract was prepared by mixing PKC with sugar at a weight ratio of 1:1 and then removing PKC after incubating the mixture at room temperature for 100 days. The resulting PKC extract was examined for its physicochemical properties and antioxidant activities using Prunus mume fruit extract, which is similar to PKC extract in terms of preparation procedure and product usage, as a control. PKC extract consisted mainly of moisture (21.76%) and sugar (70.03%), leading to high viscosity. PKC extract was apparently yellowish, and therefore its browning index and color intensity were appreciably lower than the control (P=0.0000), indicating that Maillard reaction was not facilitated during fermentation. Compared with the control, PKC extract was not appreciably different in terms of total flavonoid content, whereas its organic acid content and total reducing capacity were significantly lower. Nevertheless, its metal-chelating activity and DPPH radical scavenging activity were comparable to those of the control. In addition, SOD-like activity of PKC extract was 2-fold higher than that of 6.6 mM quercetin, which had a higher total flavonoid content than PKC extract. This indicates that PKC extract contains certain flavonoids with higher antioxidant activities than quercetin. The results show that PKC extract provides antioxidant activity as well as characteristically different sensory properties due to its higher sugar and lower organic acid contents compared with Prunus mume fruit extract.

• Journal of Mushroom
• /
• v.13 no.3
• /
• pp.228-232
• /
• 2015

'Nongjin-go' is a new breed strain of Lentinula edodes, saw-dust bag variety. It is a cross combination of dikaryon Lentinula edodes ASI 3305mut and monokaryon L5-16 of L. edodes ASI 3305(Sanjo701ho). We crossbred them by 2011 and verified productive capacity from 2012 to 2013 in Rural Development Administration. Optimum temperature of mycelial growth is $30^{\circ}C$ and it of fruit-body primodium formation is range from 15 to $23^{\circ}C$. Nongjigo is agricultured at mid-high temperature well. Fruiting body is platy-hemisphere, light brown and centralizing. And bast is formed around edge of pileus. Yield productions per period is regular than 'Sanjo701'. Plastic bag culture medium is 1.5 kilogram and culture periods are 90~100 days. As its browning of pileus in culture is a little slow, Light and ventilation is needed a lot in light-culturing. Humidity is controlled properly for its color in fruit-body growing. Tested culture medium is consisted of 80% Oak-Tree saw-dust and 20% rice-bran.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.16 no.2
• /
• pp.131-136
• /
• 2014

This study was carried out to determine the effects of wind speed on physiological responses in 'Fuji' apple (Malus pumila Miller). Two levels of wind blowing (3 and $5m{\cdot}s^{-1}$) were produced by large electric fans. Photosynthetic rate was reduced by one-way wind blowing treatment at $5m{\cdot}s^{-1}$, compared to the mild wind control, and this reduction was more obvious with stronger wind and increasing duration of wind application. The reduction in photosynthesis by the wind treatments was correlated with that in the proportion of opened stomates and stomatal conductance. The one-way wind treatment at $5m{\cdot}s^{-1}$ caused a leaf browning and leaf fall, and this negative effect became more serious with increasing time of exposure to the wind treatments. The sap flux through stem increased in all wind treatments compared to the natural mild wind.