Min-Sung Choi

Quality characteristics of reduced-fat frankfurters with pork fat replaced by sunflower seed oils and dietary fiber extracted from makgeolli lees

The effects of reducing pork fat levels from 30% to 20% by partially substituting pork fat with a mix of sunflower seed oil (0, 5, 10, 15, and 20%) and makgeolli lees fiber (2%) were investigated based on physicochemical properties, textural properties, and sensory characteristics of reduced-fat frankfurters. The moisture and ash content, and lightness were higher in reduced-fat frankfurter samples containing sunflower seed oil and makgeolli lees fiber than in the control. The results showed that reduced-fat frankfurter samples with higher sunflower seed oil levels had lower redness and yellowness values, as well as less cooking loss, emulsion stability, hardness, springiness, and apparent viscosity. The results of this study show that incorporating sunflower seed oil and makgeolli lees fiber into the formulation successfully reduced animal fat in frankfurters, while improving quality characteristics.

Effects of Replacing Pork Back Fat with Brewer's Spent Grain Dietary Fiber on Quality Characteristics of Reduced-fat Chicken Sausages.

The effects of replacing pork back fat with brewers spent grain (BSG) pre-emulsion for physicochemical, textural properties, and sensory evaluations of reduced-fat chicken sausages are evaluated. Control was prepared with 15% pork back fat, and three reduced-fat chicken sausages were formulated with the replacement of 20, 25, and 30% pork back fat with BSG pre-emulsion. The pH level of reduced-fat sausages formulated with BSG pre-emulsion is lower than that of the control (p<0.05). The redness, yellowness, and apparent viscosity of reduced-fat chicken sausages increase proportionally with increasing BSG pre-emulsion (p<0.05). With increasing BSG pre-emulsion concentration, the fat contents and energy values are decreased in reduced-fat chicken sausages (p<0.05). The BSG pre-emulsion improves the hardness, gumminess, and chewiness of reduced-fat chicken sausages (p<0.05), and the reduction in fat and the addition of BSG pre-emulsion had no influence on the cohesiveness of the chicken sausage. And there is no significant difference in the overall acceptability among control, T1 (chicken sausage with 20% of BSG pre-emulsion, 10% of fat addition), and T2 (chicken sausage with 25% of BSG pre-emulsion, 5% of fat addition) (p>0.05). Therefore, our results indicate that BSG is effective dietary fiber source for manufacturing of reduced-fat meat product and suggest that 20-25% of BSG pre-emulsion is suitable for pork back fat in chicken sausages.

Simultaneous Measurement of PPG and Functional MRI

The purpose of the current study was to develop a magnetic resonance (MR)-compatible photoplethysmograph (PPG) system which could measure the raw PPG signal during MR image acquisition. The system consisted of an optic sensor which measured the optic signal, an optic cable which transmitted a near-infrared optic signal, a signal amplifier, and a filter for noise removal. To minimize interactive noise, only the optic cable and the optic sensor module were located inside the MR room; the signal amplifier and filter were located outside the MR room. The experiment verified that a reliable PPG signal can be obtained without deteriorating the MR image. Especially, it was possible to get a reliable PPG signal while acquiring MR images with EPI method which has been used for functional magnetic resonance imaging (fMRI) study. This system can simultaneously measure the response of the central nervous system using fMRI and that of the peripheral nervous system using the PPG.

Combined Effects of Mugwort Herb and Vitamin C on Shelf-Life of Vacuum-Packed Seasoned Pork.

This study was performed to investigate the possibility of the addition of mugwort herb extract (MH) and vitamin C (VC) alone (0.05%) and in combination (0.05% each) on shelf-life of seasoned pork. The combination of VC+MH demonstrated a significant reduction in thiobarbituric acid reactive substances, and volatile basic nitrogen in seasoned pork. Also, the pH values, total lactic acid concentration, lactic acid bacteria count, and the sensory properties (discoloration, flavor, and overall acceptability) of seasoned pork were not significantly affected by adding MH and/or VC. All seasoned pork were rejected by sensory panel when LAB count reached levels of 5-6 Log CFU/g, TLA concentration has been above a level of 3.6-3.9 mg lactic acid/g, and pH values ranged from 5.31-5.51 (15 d). Therefore, the findings showed that spoilage of seasoned pork does not appear to be the result of lipid oxidation, but is caused by lactic acid producing bacteria which result in sour odor.

Effect of Mixing Ratio between Pork Loin and Chicken Breast on Textural and Sensory Properties of Emulsion Sausages.

This study is conducted to evaluate the effects of the mixing ratio between pork loin and chicken breast for textural and sensory properties of emulsion sausages. Meat homogenates are prepared by using five mixing ratios between pork loin and chicken breast (100:0, 70:30, 50:50, 30:70, and 0:100), and the emulsion sausages are also formulated with five mixing ratios. The additions of chicken breast increase the salt soluble protein solubility due to high pH levels of chicken breast, thereby resulting in the reduction of cooking losses. In addition, the apparent viscosity of meat homogenates increase with increasing amounts of chicken breast. In terms of emulsion sausages formulated with pork loin and chicken breast, the addition of chicken breast above 50% may contribute to a softer and more flexible texture of emulsion sausages. For sensory evaluations, an increase in the added amount of chicken breast contributes to a rich umami taste and deeper flavor within the emulsion sausages, resulting in the high overall acceptance score for the formulation of 0-30% pork loin and 70-100% chicken breast. Therefore, the optimal mixing ratios between pork loin and chicken breast are 0-30% and 70-100% for enhancing the textural and sensory properties of emulsion sausages.

A Study of the Jerk Cost Function for Evaluating Quantitative Driving Performance during Simulated Driving

The purpose of this study was to test whether the jerk, the third derivative of the position, can be used as a quantitative driving performance index during simulated driving. Sixty healthy adults having 1-3 years driving experience were participated in driving simulator experiment. All subjects were instructed to keep constant distance from front vehicle running at 55~65km/hr speed on straight road. Each 10 males and 10 females were randomly selected in condition of keeping a constant distance with 20m, 25m and 30m, respectively. Experiment consisted of straight driving for 1 min and unexpected situation caused by emergency stop of the front vehicle. To collect 3D kinematic data, 10 markers were attached on the subjects’ upper (elbow, wrist and hand) and lower (knee, exterior knee, ankle, and toe) limbs and 3D motion capture system was synchronized with the driving simulator. The data was divided into unexpected situation section for 2 sec. To evaluate the driving performance, the jerk cost function (JCF) which indicates the smoothness of motion was calculated for all makers. The probability of collision was significantly smaller at the distance of 30m compared with 20m and 25m (p<.05). JCF of upper limbs did not show any significant patterns in distance between vehicles for unexpected section. However, JCF of lower limbs (knee, ankle and toe) showed significantly smaller values as the distance between vehicles was increased for unexpected situation section (p<.05). The probability of collision was decreased and the driving performance was increased with decreased JCF as the distance between vehicles was increased. Thus it can be concluded that JCF could be used as one of the parameters for evaluating the driving performance quantitatively.

Development of a Magnetic Resonance Compatible Motion Signal Measurement System

The purpose of this study was to develop 3-axis Magnetic Resonance (MR) compatible motion measurement system which can measure motion signals without deteriorating MR image. 3-axis accelerometer was used to measure motion signals and velcro was used to attach accelerometer module to finger or wrist. To minimize mutual interference effect between MR imaging system and motion measurement system, amplifier circuit was made of analog devices and amplifier was located at the shielded case which was made of copper and aluminum. Motion signal was modulated to optic signal by using Pulse Width Modulation (PWM) and modulated optic signal was transmitted to outside MR room by using Light Emitting Diode (LED) and optic cable. Measurement of 3-directional acceleration was possible with 3-axis accelerometer. It was verified that functional Magnetic Resonance imaging (fMRI) and motion signals were measured simultaneously and stably.

A Study on the Cerebral Lateralization Index using Intensity of BOLD Signal of functional Magnetic Resonance Imaging

This study proposes a new cerebral lateralization index on the basis of neural activation intensity. Eight right-handed male college students (mean age 23.5 years) and ten right-handed male college students (the mean age — 25.1 years) participated in this study of visuospatial and verbal tasks, respectively. Functional brain images were taken from 3T MRI using the single-shot EPI method. A cerebral lateralization index based on neural activation area (i.e. number of activated voxels) and another based on neural activation intensity (i.e. intensity of BOLD) were calculated for both cognition tasks. The result of calculating a cerebral lateralization index based on neural activation area suggested that the right hemisphere is dominant during visuospatial tasks and the left hemisphere is dominant during verbal tasks. When a cerebral lateralization index was computed on the basis of the neural activation intensity, it was shown that the area of cerebral lateralization closely related to visuospatial tasks is the superior parietal lobe, and the area of cerebral lateralization closely related to verbal tasks is the inferior and middle frontal lobes. Since the proposed method can determine the dominance of the cerebrum by each area, it can be helpful to determine cerebral lateralization accurately and easily.

Changes of Regional Activation to a Spatial Cognition Task with Aging: An fMRI Study

This study investigated the effect of aging on spatial cognition performance and regional brain activation. Eight right-handed male college students in their twenties (mean age 21.5 years) and six right-handed male adults in their forties (mean age 45.7 years) who were graduated from college participated in the study. A spatial task was presented while brain images were acquired by a 3T functional Magnetic Resonance Imaging (fMRI) system. Compared to the 40s the 20s showed higher spatial performance. Increased brain activations were observed in the parietal and superior frontal lobes at 20s compared to 40s. There was more activation observed in the middle frontal and right inferior frontal lobes at 40s compared to 20s.