Sang Sook Kim

Effect of Milling Ratio on Sensory Properties of Cooked Rice and on Physicochemical Properties of Milled and Cooked Rice

ABSTRACT Quantitative descriptive analysis of cooked rice was performed to investigate the effect of milling ratios (≈8.0–14.0%, based on brown rice) on sensory characteristics of cooked rice, in relation to physicochemical characteristics of milled rice and cooked rice. The proximate composition of uncooked rice decreased with increased milling while whiteness increased. The initial pasting temperature of rice flour decreased with increased milling while peak, breakdown, and setback viscosities increased. The instrumental texture profile of cooked rice revealed that hardness and chewiness decreased with increased milling while adhesiveness increased. A trained panel found that color, intactness of grains, puffed corn flavor, raw rice flavor, wet cardboard flavor, hay-like flavor, and bitter taste were lower while glossiness, plumpness, and sweet taste were higher with increased milling. Degree of agglomeration, adhesiveness, cohesiveness of mass, inner moisture, and toothpacking of cooked rice increased ...

Physicochemical Characteristics of Chalky Kernels and Their Effects on Sensory Quality of Cooked Rice

ABSTRACT Physicochemical characteristics of chalky rice kernels were compared with those of vitreous kernels, and the effects of chalky kernels on sensory quality of cooked rice were investigated. Chalky kernels were compared with vitreous kernels using image analysis and amylose contents. Because cooked rice is prepared through soaking and cooking, the changes in water absorption index (WAI) during soaking (15, 30, 60, and 90 min) and the structural changes during cooking (0, 3, 6, and 9 min) in chalky and vitreous kernels were investigated using image analysis and scanning electron microscopy. The effects of various proportions (0, 4, 6, 8, 10, and 15%) of chalky kernels on sensory quality of cooked rice were also studied. The chalky kernels tended to be smaller in kernel area, maximum diameter, minimum diameter, and perimeter than vitreous kernels. Amylose content in chalky kernels was slightly lower than that in vitreous kernels. WAI of chalky kernels was higher than that of vitreous kernels. The effe...

Authentication of Rice Using Near-Infrared Reflectance Spectroscopy

ABSTRACT The authentication of rice (Korean domestic rice vs. foreign rice) has been attempted using near-infrared spectroscopy (NIRS). Two sample sets (n1 = 280 and n2 = 200) were used to obtain calibration equations and the spectral regions used for this study were 500–600 nm, 700–900nm, and 980–2,498 nm. Modified partial least square (MPLS) regression was used to develop the prediction model. The standard error of cross validation (SECV) and the r2 were 0.165 and 0.91 respectively for 1st calibration set and 0.165 and 0.93 for 2nd calibration set respectively. The results of the independent validation (n3 = 80) showed that all of 80 samples were identified correctly. Even though authentication of rice was performed successfully using NIRS, the calibration statistics in this study showed that further effort is needed for implementation of NIRS for authentication of rice for industry purposes.

Authentication of rice by three-sided image analysis of kernels using two mirrors

ABSTRACT The authentication of rice by imaging three sides (top, side, and front) of a rice kernel using two mirrors was attempted. Nine image characteristics (area, aspect ratio, minimum diameter, maximum diameter, perimeter, and red, green, and blue values) for each side of a rice kernel were measured. Japonica type rices were used for the study; a total of 89 rice samples were used: 40 samples harvested in Korea, 33 in America, 5 in Australia, and 11 in China. Image data collected from 105 kernels per rice sample were used as a calibration data set to develop a model for quadratic discriminant analysis. In overall pairwise trials, on average, 85.8–94.5% correct identification of the cultivated country was obtained, depending on the number of image characteristics used for the discriminant model. For the effective discrimination of the cultivated country, 13 image characteristics were selected. As a test sample set, 20 kernels per sample were used. A model for discriminant analysis with 13 image charact...

Effects of rice flour size fractions on gluten free rice bread

Fractionation (F-1, F-2, and F-3) of semi-dry milled rice flour (SDMRF) was performed using air-classification wheel speeds (ACWS, 1,000, 2,000, and 3,000 rpm) to identify suitable size fractions for preparation of gluten-free rice bread (GFRB). Characteristics and effects of fractions on GFRB were investigated. Fractions had higher water absorption indices than unfractionated flour (control). Fractions were smaller in size, and the amount of damaged starch was larger for higher ACWS values. The F-1 fraction had higher peak viscosities and specific volumes than other fractions. The F-3 fraction had lower values. GFRB prepared using the F-1 fraction had a lighter air-cell structure and lower hardness than control bread. From sensory evaluations, the particle size of SDMRF affected the appearance of GFRB. GFRB prepared using the F-1 fraction had more uniform and smaller air-cells. The quality of GFRB can be improved by controlling the particle size of flour.

Effect of Storage Temperature for Paddy on Consumer Perception of Cooked Rice

ABSTRACT Effect of storage temperature (ST) (5, 15, and 25°C) for paddy on the consumer perception of cooked rice (CR) was investigated with six major rice cultivars in Korea (Ilmibyeo, Chucheongbyeo, Ilpumbyeo, Hwayeongbyeo, Nampyeongbyeo, and Odaebyeo) after 12 months of storage. Germination rate (GR) of the paddy, grading characteristics (percentages of head rice, broken kernels, damaged kernels, colored kernels and chalky kernels) of milled rice (MR) kernels, texture profile analysis (hardness, springiness, cohesiveness, adhesiveness, and chewiness) and color (L*, a*, and b*) of CR were measured. Also, consumer testing on CR was done with 108 consumers. Consumers evaluated acceptability for odor, appearance, taste, texture, and overall purchase intent, and willingness to pay (WTP) of CR. After 12 months of storage, physicochemical characteristics of MR and CR were significantly different depending on ST. The significant difference among three ST of paddy was noted for GR, color b* value, fat acidity o...

Effects of ozone treatment on physicochemical properties of Korean wheat flour

The objective of this study was to investigate the effects of ozone treatment on the physicochemical properties of Korean wheat flour. Wheat flour samples were treated with ozone gas at 120 ppm for 15, 30, 45, and 60 min. Color b value, pH, and mold of flour decreased as exposure time to ozone increased. The water absorption index, peak viscosity, and final viscosity of flour increased by ozone treatment. Photomicrographs of flour suspensions under polarized light showed granules tended to lose birefringence owing to ozone during swelling. The result of SDS-PAGE showed that the intensity of protein bands at low molecular weights slightly increased in ozone-treated flours compared to the intensity in the control flour. The results of this study showed ozone gas affected the starch and protein of wheat flour, suggesting a need for further investigation on structural changes in starch and protein by ozone.

Importance of Applying Condiments in a Commonly Consumed Food System for Understanding the Association Between Familiarity and Sensory Drivers of Liking: A Study Focused on Doenjang : Sensory preference drivers of Deonjang…

Doenjang, a Korean traditional fermented soybean paste, is one of the most essential condiments in Korean cuisine. Condiments are rarely consumed as it is, and are generally applied to other foods. The objective of this study was to understand how sensory drivers of liking of Doenjang would be affected according to food forms in which it is evaluated: the original paste form compared with a normally consumed soup form, and to understand the association of familiarity of evaluated food form. Descriptive analysis and consumer acceptability test was performed in 2 consumption forms: the original paste form and the Doenjang soup from. For consumer liking test, elderly consumers who have more experience to traditional Deonjang were compared to the young in their response to Doenjang paste and soup. The descriptive analysis results showed that the characteristic sensory features of the Deonjang samples were little affected based on the food system in which it was evaluated. However, when the paste was applied in soup, the intensities of the characteristic sensory features were reduced. Acceptability and familiarity of traditional type Doenjang samples for the young and for the elderly consumers were very similar in paste, but it differed when the samples were evaluated in soup. Thus, expectation difference between the young and the elderly was better revealed in soup, a more common food form consumed in practice. The results of this study indicate the importance of understanding sensory drivers of liking for a condiment such as Doenjang in their commonly consumed forms. PRACTICAL APPLICATION Compared to the original condiment form, expectation difference between the young and the elderly were better revealed in Deonjang soup, a food form normally consumed in practice. Thus, the results of this study reinforced the importance of investigating sensory drivers of liking for a condiment in a food form that is normally consumed in practice for accurate understanding on consumer preference.

Comparison of physicochemical characteristics and consumer perception of rice samples with different countries of origin and prices

BACKGROUND Rice is the only food item which is not liberalized in Korea. To prepare for future liberalization of the rice market in Korea, the physicochemical characteristics and consumer perception of four domestic rice samples were compared with those of 11 foreign rice samples. Additionally, the influences of country of origin (CO) and price on purchase intent (PI) and willingness to pay (WTP) were investigated. RESULTS Consumer acceptance of rice samples from Japan was generally higher than that of rice samples from other countries. In an informed test, PI was affected by price and CO, while WTP was affected mostly by price. The PI decreased with the price provided while the WTP increased. In a blind test, consumers evaluated PI and WTP according to sensory liking. The PI was higher in the informed test than in the blind test in all domestic samples. Generally, consumer acceptance was highly correlated with fat acidity (r = - 0.76), protein content (r = - 0.72), and b value (r = - 0.64) of the rice samples. CONCLUSION Further efforts to increase the quality of rice are recommended for survival in the global market after liberalization of rice, even though consumers showed loyalty for PI of domestic samples.