• Korean Journal of Food Science and Technology
• /
• v.34 no.6
• /
• pp.1023-1029
• /
• 2002

Relationship between RVA properties and physical properties of film made from native corn starch and hydroxypropylated corn starch at various levels of plasticizers was examinel. Tensile strength of the film decreased, but its elongation and water vapor permeability increased with increasing plasticizer concentration. The film with glycerol showed greater changes in physical properties than that with sorbitol. Hydroxypropylated starch film showed lower tensile strength, higher elongation, and higher water vapor permeability than the native starch film. Sorbitol resulted in films with relatively high tensile strength, whereas glycerol produced films with increased elongation. The most reliable parameters for the relationship between RVA properties and film properties were RVA peak viscosity, tensile strength, and water vapor permeability. Water vapor permeability and tensile strength had linear relationship with RVA properties. The tensile strength and water vapor permeability of film could be predicted using the RVA peak viscosity.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.32 no.5
• /
• pp.582-586
• /
• 1999

The processing conditions for producing and edible alginate film from sea tangle were investigated by measuring water vapor permeability (WVP), tensile properties and colors of film. The alginates were extracted with $3\%$ sodium carbonate ($Na_2CO_3$) solution for 5 hrs, and the alginate films were prepared with extracted sodium alginates, D-gluconic acid lactone, $CaCO_3$ and various plasticizers, As the concentration of alginate in making the film was increased, the WVP and elongation of the film were decreased and the tensile strength was increased. The higher amount of plasticizer showed the higher WVP and elongation, and the order of various plasticizers in increasing the WVP and elongation of the film was glycerol, polyethylene glycol, and sorbitol. The addition of sorbitol in the film showed the highest value (89.57) in lightness of Hunter color system and the film added polyethylene glycol had the highest values (-1,12 and 11.4) in redness and yellowness.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.32 no.5
• /
• pp.664-668
• /
• 1999

The extracting conditions of alginates from sea tangle were evaluated by measuring water vapor permeability (WVP) and tensile properties of alginate film to obtain basic data of making an edible and biodegradable film. The alginates were extracted with $1\%,\;3\%$ and $5\%$ sodium carbonate ($Na_2CO_3$) for 1, 3, 5 and 10 hours, and the alginate film was made with various plasticizers. The higher concentration of $Na_2CO_3$ solution showed the lower viscosity and polymerization degree of alginate and the film prepared with alginates having low viscosity showed the higher WVP. The extracting hours had little effect on the WVP and the elongation of alginate film, but the polymerization degree of alginates directly affected the tensile strength of the film. The addition of sorbitol and polyethylene glycol as a plasticizer lowered the WVPs and the elongation of alginate film.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.33 no.5
• /
• pp.413-417
• /
• 2000

The effects of film processing conditions on the water vapor permeability (WVP), the solubility of film's protein (SFP) and the soluble film's meterials amount (SFMA) were investigated to establish the conditions for preparing biodegradable and edible Alaska Pollack meal protein isolate (APMPI) film. ms of film were decreased with increasing plasticizer concentration but those were decreased with decrement of APMPI's pH values. SEPs were decreased with increasing APMPI's pH and plasticizer concentration. SFMAS were also strongly affected by plasticizer concentration and APMPI's pH. In the case of adding different plasticizers, WVP was increased in order as follows: glycerol, polyethylene glycol and sorbitol but SFMA showed inverse order.

• Korean Journal of Soil Science and Fertilizer
• /
• v.44 no.4
• /
• pp.534-538
• /
• 2011

One of the problems for cultivating crops in the mountainous highland is soil erosion and nutrients runoff. Alternative cropping ways were searched to reduce soil erosion and to ensure farm income in the mountainous highland agricultural region. Three edible wild plants including goatsbeard, Korean thistle, and aster, were selected to test as alternative crops to reduce soil erosion in mountain agriculture of highland area. In the first year, the soil losses from the alternative cropping were 26 to 63 percents of the soil loss from summer radish cultivated by conservation tillage with contour and plastic film mulching. The relative soil losses in the second year ranged from 2.8 to 5.5 percents in comparison with radish cultivation. Rapid surface coverage contributed to successive soil loss protection by these alternative crops. Farm net profit of these crops was greater than that of radish. Monitoring of yields of Korean thistle or aster for further experiments, however, might be necessary for economic cultivation due to yield reduction caused by consecutive production.

• Korean Journal of Food Science and Technology
• /
• v.30 no.6
• /
• pp.1381-1387
• /
• 1998

Laminated films were prepared by casting corn-zein and fatty acid mixed solutions onto ${\kappa}-carrageenan$ films, and the effect of various fatty acids with different concentrations on the film properties such as water vapor permeabilities (WVP), tensile strength (TS) and elongation was investigated. WVP of the film decreased as concentration of fatty acids increased, and the lowest WVP value $(0.497\;ng\;m/m^2\;s\;Pa)$ was achieved with laminated films containing 30% lauric acid/corn-zein. The TS of laminated edible film seemed to decrease as the concentration of fatty acids increased, and TS of the laminated film was the highest (36.21 MPa) when the film contained 10% oleic acid. Weight loss of the minced mackerels packaged with corn-zein/carrageenan film which did not contain fatty acid was 11.7%, but weight losses of the samples packaged with oleic acid and lauric acid were 6.97% and 0.81%, respectively, after 30 days storage at $-20^{\circ}C$. The laminated films had an effect on preventing oxidation of the minced mackerels during storage because of high oxygen barrier property of the film. All of the minced mackerels packaged with the laminated films greatly reduced the peroxide value (POV) compared with unpackaged minced mackerels during storage. Also, thiobarbituric acid (TBA) values of the minced mackerels packaged with the laminated films were lower than that of unpackaged minced mackerels during storage.

• Korean Journal of Food Science and Technology
• /
• v.30 no.2
• /
• pp.379-384
• /
• 1998

Biodegradable carrageenan films and carrageenan-coated papers were developed and their characteristics of lipid permeation was investigated for possible substitution of PE-coated papers used in packaging of oily or greasy foods. Both carrageenan coated papers and free carrageenan films were highly resistant to lipid penetration. Among the carrageenans tested, ${\kappa}-carrageenan$ film showed the most resistant followed by ${\lambda}-$ and i-carrageenan films. The resistance to lipid increased as the thickness of ${\kappa}-carrageenan$ layer increased. Carrageenan coated papers with $4\;and\;5\;kg/ream\;(278m^2)$ showed the lipid resistance comparable to that of the PE-coated paper. Free films also showed the same trends of the lipid resistance as the carrageenan coated papers, but the degree of lipid resistance was approximately ten times higher than that of carrageenan coated paper. Degree of lipid penetration of carrageenan films and carrageenan-coated papers increased exponentially against time. ${\kappa}-carrageenan$ coated papers over 4 kg/ream showed to have an adequate lipid barrier property for being utilized for packaging greasy food products.

• Korean Journal of Food Science and Technology
• /
• v.29 no.6
• /
• pp.1184-1190
• /
• 1997

Corn zein coated carrageenan films were manufactured by immersing preformed ${\kappa}-carrageenan$ films into solution of different concentrations of corn zein (CZ) solids (10, 20, and 30% in 95% ethyl alcohol) with polyethylene glycol (20% w/w of CZ), glycerol (24% w/w of CZ). For all types of films, water vapor permeability (WVP), water solubility (WS), swelling ratio (SR), tensile strength (TS), percent elongation at break (E), heat sealing strength (HS), and Hunter color values (L, a, and b) were determined. WVP of corn zein coated ${\kappa}-carrageenan$ films decreased significantly (p<0.05) as the concentration of com zein increase. Coating with corn zein also decreased film WS and SR linearly with the concentration of corn zein. TS of corn zein coated carrageenan films decreased linearly with corn zein concentration. All the com rein coated carrageenan films showed heat sealing properties even though their sealing strength was less than half of corn zein film. Obviously corn zein coating affected color of ${\kappa}-carrageenan$ films, which was mainly caused by increase in yellowness (Hunter b-value).

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.35 no.4
• /
• pp.417-423
• /
• 2002

The edible films were prepared from the protein of alaska pollack, Theragra chalcogrmma. Effects of plasticizer, cross linker and laminated film on physical properties such as tensile strength (TS), elongation (E) and water vapor permeability (WVP) of films were investigated. In adding various kinds of plasticizers, TS of the films prepared with propylene glycol (PG) was the highest, and followed sorbitol, polyethylene glycol 200 (PEG 200) and glycerol. Elongation of the films prepared with glycerol was the highest, then sorbitol, PEG 200 and PG. WVP of films showed lower in order of PG, sorbitol, glycerol and PEG 200.75 decreased with the increment of plasticizer concentration, but elongation increased, The addition of both PG and PEG 200 effected weakly on elongation, so they were inadequate as plasticizer for the film. Mixtures of glycerol and sorbitol, which showed opposing both TS and elongation in the films, could control the physical properties of the films. With increasing relative humidity, TS decreased, while elongation and equilibrium moisture content increased. By adding the cross linkers such as ascorbic acid, citric acid and succinic acid, TS and m of films increased, while elongation decreased. Ascorbic acid, citric acid, succinic acid were most effective for TS at 0.2, 0.1 and $0.1\%, respectively. Laminated film with alaska pollack protein and corn zein improved TS above two times, reduced WVP about $20\~30\%$, as compared with the Elm from alaska pollack protein. Two films did not show the difference to oxygen permeability, but they showed about tenfold greater oxygen resistance than polyethylene film. Laminated film showed higher b and $\Delta$E value of color difference, lower a and L value than the film from alaska pollack protein.

• Food Science and Preservation
• /
• v.8 no.2
• /
• pp.181-186
• /
• 2001

The objective of this study is to determine the effect of soy protein isolate (SPI) film coating on the color, firmness, viscosity and weight loss of Rice Cake stored at 15, 20 and $25^{\circ}C$ (RH 50%) for 30 days. Raw materials mixed with SPI and cocoa powder (10:0, 7:3, 5:5, 3:7, w/w) were prepared. After adding sugar and shortening to raw materials, the mixture were refined to 25 micron of particle size. Coating of Rice Cake were carried out at $65^{\circ}C$. SPI coated Rice Cake had higher internal and external firmness comparing to the control at $25^{\circ}C$. SPI coated Rice Cake showed smooth surface morphology and had 0.71-1.01 mm of thickness. SPI coated Rice Cake showed less weight loss for 30 days compared to controls. SPI coating solution was successfully coated on Rice Cake and extended shelf-life over 15 days at room temperature.