• Korean Journal of Food Science and Technology
• /
• v.29 no.4
• /
• pp.663-670
• /
• 1997

Four kinds of commercial vinegars were investigated to compare physicochemical properties (pH, acidity, color, tannin and metal content), minor components (free sugar, free amino and organic acid), and their organoleptic tastes. The ratio of nonvolatile organic acid to the total organic acid was decreased in the order of brewed, cider, brown rice, and persimmon vinegar. Especially malic acid content was appeared to be highly remarkable in cider vinegar. Glucose and fructose were the predominant components among free sugars regardless of the kinds of vinegar. Free amino acid contents in cider, brown rice and persimmon vinegars have shown a little deviation among the same kind of vinegar samples, but were obviously more abundant than those in brewed vinegars. Color preference, sourness and sweetness of the vinegars were not statistically different (p>0.05) among four kinds of vinegars, whereas overall taste preference, background taste preference and intensity showed significant differences (p<0.05) with respect to the type of vinegar. Brewed and cider vinegars have revealed higher sensory scores in overall and background taste preference than the persimmon and brown rice vinegars. Even though there were no high relationships between minor components and organoleptic taste in commercial vinegars the ratio of acetic acid to the total organic acid was significantly correlated (p<0.01) with the overall taste preference.

• Korean Journal of Food Science and Technology
• /
• v.29 no.4
• /
• pp.716-721
• /
• 1997

In order to improve the quality of sikhe, Korean traditional sweat rice drink, wheat malt, covered barley malt and naked barley malt were used to prepare sikhe. The optimum temperature of amylase was $60^{\circ}C$ in malt extract. After heat treatment of amylase for 2 hr at $70^{\circ}C$, residual activity of amylase was less than 20% in malt extract. Amylase activity during sikhe preparation was decreased gradually. The sikhe saccharifyed for 6 hr had $6250{\sim}25029$ units of amylase acitivity. The contents of glucose, maltose and maltotriose were increased with increasing time. Maltose content was the highest, followed by glucose and maltotriose. The pH and titrable acidity were slightly changed. The sweetness of sikhe prepared with wheat was 11.3%, and others were 11.1% and 10.4%. The sikhe prepared with naked barley was evaluated the most palatable sikhe.

• Korean Journal of Food Science and Technology
• /
• v.37 no.6
• /
• pp.893-897
• /
• 2005

Effect of foliar application of stevia extract on strawberry quality was investigated. Soluble solid and free sugar contents of strawberry (SS) cultivated with foliar application of stevia extract were higher, and acidity and organic acid contents were lower than those of control. Free sugars were composed of fructose, glucose, and sucrose. Organic acids were composed of citric, malic, oxalic, succinic, and fumaric acids. Sensory evaluation revealed score of sweetness, sourness, and overall acceptability for SS were higher than those of control.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.13 no.1
• /
• pp.86-96
• /
• 1984

In order to provide basic data for food processors and to improve eating habits and healthy diets, four primary tastes and hot taste threshold of Koreans, physio-chemical properties of foods and food preference were investigated. The results of this study were as follows; 1. The recognition threshold concentration of four primary tastes was 0.016 % of salt, 0.245${\sim}$0.249 % of sweet, 0.004${\sim}$0.008 % of sour and 0.008${\sim}$0.012 % of bitter. Threshold concentration of hot taste was 170,000${\sim}$600,000 Scoville Heat Unit(S.H.U.) 2. The most acceptable tastes were 0.3 % saltiness in 0.375 % broth(at $60^{\circ}C$), 6 % sweetness in 2 % instant coffee(at $60^{\circ}C$) and 19.3 sugar-acid ratio(16.8 brix/0.8736 % citric acid) in 100 % valencia orange juice(at $20^{\circ}C$). 3. The salt concentrations of soup were 1.127 % in average. S. H. U. (scale of hot taste) of soybean sprout soup and spinach bean paste soup ranged between 12,500 and 47,500 equivalent to oleoresin capsicum content of 1.990${\sim}$5.911 (mg %). 4. 'Jigae' (Korean style stew) was the most favorable food and it was revealed that the father influences the formation of his children's eating habits.

• Journal of the East Asian Society of Dietary Life
• /
• v.12 no.5
• /
• pp.370-378
• /
• 2002

To assess the quality of commercial Sujongkwa, we compared physicochemical and sensory characteristics of commercial Sujongkwa with home-made one. Two different brands of Sujongkwa and home-made one were analyzed for physicochemical (sugar content, pH, acidity, color, viscosity, transparency) and sensory characteristics (7-point scoring test, 15 experienced panel members). Separately, we assessed the opinion of food and nutrition specialists about the commercial Sujongkwa. Questionnaires were hand delivered to 530 subjects consisted of university students and faculties of Department of Food and Nutrition at 8 cities (Seoul, Incheon, Yongin, Daejon, Chungju, Daegu, Kwangju, Busan) in Korea and the complete data of 328 subjects were statistically analyzed using SPSS Propam for Window (mean, ANOVA, $\chi$$^2$). The questionnaires were consisted of sociodemographics, frequency and occasion of purchasing, opinion of quality and improvement points. Both commercial Sujongkwas were lower in sugar content, transparency, color(L and b value) and viscosity, and commercial brand B was higher in pH and color a value than home-made one. Also, among sensory characteristics, over-all preference and color for brand B were significantly higher than those for brand A and home-made one (p<0.05). Especially, the scores of over-all preference were 1.9 for brand A, 5.7 for brand B, and 4.9 for home-made Sujongkwa. Points to be improved for commercial Sujongkwa were in order of sweetness (33.0%), pungency (24.2%), dried persimmon (19.1%).

• Journal of the East Asian Society of Dietary Life
• /
• v.20 no.6
• /
• pp.916-922
• /
• 2010

The quality characteristics and antioxidant activities were evaluated for jams containing fructooligosaccharide (FTO) and FTOS (sucrose 50%+FTO 50%) substituted for sucrose. The endpoint of jam preparation was determined to be sweetness of $64^{\circ}Brix$. Moisture contents differed among the treatments, whereas acidity did not. Reducing sugar content and viscosity were highest in the FTO (0.144%, 126,800 cP), and the lowest in control (0.074%, 101,600 cP). Lightness (L value), redness (a value), and yellowness (b value) values of the Hunter color system were highest in the FTO sample. Hardness and springiness of textural properties were the highest in the FTO sample as well. Antioxidant activities were the highest in the FTO sample with the lowest $IC_50$ values (42.3 mg/g for DPPH and 22.4 mg/g for hydroxyl radical scavenging activities). Total phenolic content was the highest in the FTO sample among all treatments. The overall acceptance score of black garlic jam containing FTO was the highest. Based on these results, it is suggested that FTO was appropriate for achieving good qualities such as antioxidative activity in black garlic jam.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.38 no.3
• /
• pp.377-383
• /
• 2009

Texture and descriptive sensory characteristics of a Korean rice cake (Karedduk) added with mixture of trehalose and Sun-Tender were investigated after 2, 24, and 48 hrs of storage at $5^{\circ}C$. A central composite design was used for treatment arrangement. The trehalose were added in 0, 3, 6, 9 and 12% levels and Sun-Tender added in 0, 0.3, 0.6, 0.9, and 1.2% levels to dry rice flour. The mixture amounts of trehalose and Sun-Tender on texture and descriptive sensory characteristics of a Korean rice cake (Karedduk) were optimized using response surface methodology (RSM). The two independent variables selected for the RSM were amounts of trehalose ($X_1$) and amounts of Sun-Tender ($X_2$). The predicted value at stationary point or a minimum for texture hardness by RSM was found as 591.5440 after 24 hrs of storage at $5^{\circ}C$. Also the adhesiveness, hardness, cohesiveness and sweetness by sensory characteristics were significantly different as compared to the control. The results suggested that a Korean rice cake (Karedduk) added with mixture of trehalose and Sun-Tender can be made from the mixture amounts of trehalose 9.5826% and Sun-Tender 0.2216% in retarding retrogradation.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.38 no.11
• /
• pp.1595-1599
• /
• 2009

Ginseng is one of the most well known medicinal plant in East Asia with many bioactivities. The purpose of this study was to evaluate the quality properties of cookies added with different concentrations (0, 1, 3, and 5%) of ginseng powder by molecular press dehydration (MPD) method. MPD was known to be an excellent tool for keeping taste and flavor without any loss of original materials. The results indicated no significant difference in the density of cookie dough with different concentrations of ginseng powder. The L color value was decreased and the a color values were increased with increasing concentrations of ginseng powder (p<0.05). However, there was no significant difference in the b values. Spread factor of cookie was not significantly different between 1% and 3%, but decreased at 5% (p<0.05). The hardness of cookies was significantly increased as ginseng powder concentration increased. The result of sensory score showed that cookie added with 1% ginseng powder had higher color, sweetness, overall acceptability scores than other samples. As a result of this study, quality of cookies with added 1% ginseng powder were the most suitable in terms of its color, texture, and sensory properties.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.34 no.7
• /
• pp.1091-1097
• /
• 2005

This study was carried out to develop jelly food using dried persimmon. Jelly products were prepared with the ratio of 5, 10, 15, 20 and $25\%$ of dried persimmon extract. Quality characteristics of its products were investigated. Proximate compositions of jelly were $6.74\~14.03\%$ of moisture, $6.83\~7.53\%$ of crude protein, $0.62\~1.16\%$ of crude lipid, $2.61\~13.21\%$ of crude ash, respectively. Water activity and brix $(\%)$ of jelly products ranged from 0.678 and $56.66\%\;to\; 0.748\;and\;76.59\%$. The pH and total acidity of jelly products ranged from 5.30 and $0.06\%$ to 5.38 and $0.09\%$. In the Hunter's color values, L, a and b vaules of jelly products were increased, respectively. Major free-sugar and organic acid of jelly products were maltose ($753\~1,297mg/100g$) and malic acid (263mg/100g in $25\%$ dried persimmon jelly). Major mineral of jelly products was K ($69.64\~154.37mg/100g$). In the texture property, addition of dried persimmon extract decreased gumminess and chewiness. In sensory score of dried persimmon jelly, color, flavor, texture and sweetness of $15\%$ dried persimmon jelly were high score, taste and overall acceptance of jelly products were high score, respectively. Judging from research results of the jelly products, recommended substitution level for addition of dried persimmon extract in jelly was $10\~15\%$.

• Food Science and Preservation
• /
• v.14 no.6
• /
• pp.578-583
• /
• 2007

This study was conducted to evaluate the effect of high $CO_2$ pre-storage treatment on the quality of tomatoes (Lycopersicon esculentum Mill.) during ripening. Tomatoes at different maturity stage of breaker and pink were treated in air, or $CO_2$ (25, 50, 100%) for 24 hr at $20^{\circ}C$ before ripening in air at $20^{\circ}C$. Change of surface colour and softening were reduced by high $CO_2$ treatment of all concentrations. This effect of $CO_2$ on the colour and softening was higher in breaker fruit than pink fruit. $CO_2$ concentration of $25{\sim}100%$ did not affect on soluble solids content during ripening period. Titratable acidity of breaker tomatoes were reduced by 100% $CO_2$ treatment. High $CO_2$ treatment slightly reduced sweetness of breaker tomatoes. Acidity and texture of tomatoes increased with high $CO_2$ treatment. Off-flavour was denoted by $CO_2$ treatment in pink tomatoes. The external $CO_2$ injury developed after 22 days at $20^{\circ}C$ in pink tomatoes when treated with ${\geq}25%$ $CO_2$ and in breaker tomatoes with ${\geq}50%$ $CO_2$.