Prediction of atrial fibrillation in patients with embolic stroke with undetermined source using electrocardiogram deep learning algorithm and clinical risk factors

Background

Combining the artificial intelligence algorithm with the known clinical risk factors may provide enhanced accuracy for prediction of the hidden atrial fibrillation (AF) in patients with embolic stroke with undetermined source (ESUS).

Purpose

We aimed to develop enhanced prediction models for AF with deep learning algorithm (DLA) and clinical predictors in patients with ESUS. The DLA was created to identify the patients with paroxysmal AF based on their electrocardiograms (ECG) during sinus rhythm.

Methods

We analyzed the 221 patients who underwent insertable cardiac monitor (ICM) for AF detection following ESUS. The DLA was previously developed with sinus rhythm ECGs of 10,605 paroxysmal AF patients and 50,522 non-AF patients. The convolutional neural network was used for the DLA. The primary endpoint was defined as any AF episode lasting over 5 min by ICM. The atrial ectopic burden (AEB) was calculated as the percentage of the number of conducted QRS by atrial ectopy on Holter monitoring.

Results

AF (≥5 min) was detected by ICM in 32 patients (14.5%) during follow-up period of 15.1±8.6 months. AF patients had higher AEB (0.199% vs 0.023%, p<0.001), larger left atrial diameters (LAD, 41.2 mm vs 35.7 mm, p<0.001), and larger left atrial volume index (LAVI, 46.4 ml/m2 vs 32.3 ml/m2, p<0.001) than those without AF. The means of calculated probabilities of AF by DLA were higher in patients with AF than those without AF (63.8% vs 40.2%, p<0.001). In the receiver operating characteristic curve analysis, the areas under the curve (AUC) were the highest in DLA (0.824) followed by AEB (0.784), LAVI (0.780), and LAD (0.768). The multivariable model with AEB, LAVI, and DLA demonstrated excellent prediction accuracy for paroxysmal AF (AUC: 0.902, Figure 1)

Conclusions

In patients with ESUS, the DLA outperformed other clinical risk factors for prediction of AF. Combining DLA with AEB, LAD and LAVI could is a potential useful tool to predict AF in ESUS patients.

Funding Acknowledgement

Type of funding sources: None.

Deep learning-based electrocardiogram analysis detecting paroxysmal atrial fibrillation during sinus rhythm in patients with cryptogenic stroke: validation study using implantable cardiac monitoring

Background

Atrial fibrillation (AF) is the most cause of cardioembolic source causing cryptogenic stroke. In these, anticoagulation therapy could reduce recurrence of stroke. However, paroxysmal AF would not be detected even by 24 hours Holter monitoring. Deep learning-based electrocardiogram (ECG) analysis models were recently developed to detect AF during sinus rhythm.

Purpose

We aimed to develop a deep learning algorithm (DLA) to detect AF during sinus rhythm and validate the model in patients with cryptogenic stroke who underwent implantable cardiac monitoring (ICM) to diagnose paroxysmal AF.

Methods

This cohort study involved three hospitals (A, B, and C). We developed a DLA to detect AF using sinus rhythm 10 s 12-lead ECG. We included adult patients aged ≥18 years from hospital A and B. We used development data from AF adult patients who had at least one atrial fibrillation rhythm in the study period (Jan 2016 to Dec 2021) and non-AF patients who had no reference to AF in the ECG and electronic medical record. DLA was based on convolutional neural network (CNN) using 10 s 12-lead. For external validation, the ECGs from 217 patients (hospital C) with cryptogenic stroke who underwent ICM were analyzed by using the DLA for validating the accuracy in the real-world clinical situations.

Results

We included 10,605 AF adult patients and 50,522 non-AF patients as development data. During the internal validation, the area under the curve (AUC) of the final DLA based on CNN was 0.793 (95% Confidence interval 0.778–0.807). In external validation data from cryptogenic stroke patients, the mean ICM duration was 15.1 months, and AF >5 mins was detected in 32 patients (14.5%). The diagnostic accuracy of DLA was 0.793 to detect AF during sinus rhythm, and AUC was 0.824. The sensitivity, specificity, positive predictive value, and negative predictive value of the model were 0.844, 0.784, 0.403, and 0.967, respectively, which outperformed other conventional predictive methods based on clinical factors, such as CHARGE-AF, C2hest, and HATCH.

Conclusions

In this study, DLA accurately detected paroxysmal AF using 12-leads normal sinus rhythm ECG in patients with cryptogenic stroke and outperformed the conventional models. The DLA could be used as a screening tool to identify the cause of stroke in the future.

Funding Acknowledgement

Type of funding sources: None.

Effect of Feeding Alfalfa and Concentrate on Meat Quality and Bioactive Compounds in Korean Native Black Goat Loin during Storage at 4°C

The primary aim of this study was to evaluate the effect of feeding alfalfa: Concentrate at different ratios (8:2 or 2:8) to Korean native black goats (KNBG) for 90 days on meat quality and bioactive compound content. Feeding KNBG alfalfa and concentrate at different ratios did not impact meat pH, color, microorganism composition, volatile basic nitrogen levels, or lipid oxidation. The low alfalfa (KLA) group exhibited increased oleic acid and monosaturated fatty acid levels, both of which impact the palatability traits of meat. The abundance of bioactive compounds increased in the loin meat of the KLA group, leading to an increase in antioxidant activities. Our results suggest that feeding alfalfa and concentrate at a 2:8 ratio to KNBG can increase taste-related fatty acids and bioactive compounds in loin meat, relative to that achieved by feeding at an 8:2 ratio. Further investigation is required to evaluate the quality and the metabolites of bioactive compounds in KNBG meat and the effect of the different dietary ratios of forage and concentrate.

Quality Characteristics of Samgyetang according to the Sodium Chloride Level and with/without Phosphate in Broth

In this study, the effect of sodium chloride (salt) concentration and phosphate on the quality properties of samgyetang was investigated. Increasing the salt concentration by 0.5% increased the moisture and ash content, salinity, water holding capacity (WHC), and thiobarbituric acid reactive substances (TBARS), whereas the protein content, pH, cooking losses, and shear forces were decreased. Addition of phosphate to the brine increased the pH and WHC, but decreased the TBARS, cooking losses, and shear forces. In a sensory evaluation, the scores for flavor and overall acceptability were the highest when the salt concentration of the brine was 2.0%. Overall, this study shows that the salt concentration and addition of phosphate to the brine of samgyetang substantially influences the overall quality of the chicken breast. Based on quality measurements and sensory scores, a 2.0% salt concentration with the addition of phosphate appear to be the most suitable conditions for the manufacturing of marinated samgyetang.

Combination effects of nitrite from fermented spinach and sodium nitrite on quality characteristics of cured pork loin

Objective

The purpose of this study was to investigate the effect of fermented spinach derived nitrite and sodium nitrite on cured pork loin.

Methods

The following treatments were prepared using brine (8% [w/v] salt): Control (−), no nitrite added; Control (+), 0.08% (w/v) sodium nitrite brine; T1, 0.04% (w/v) nitrite fermented spinach juice in 0.04% (w/v) sodium nitrite brine; T2, spinach juice in 0.04% (w/v) sodium nitrite brine; T3, 0.04% (w/v) nitrite fermented spinach juice used as sodium nitrite free brine; and T4, spinach juice used as sodium nitrite free brine. T2 and T4 were incubated to allow to reduce nitrate to nitrite.

Results

Spinach juice did not affect cooking loss and pH but negatively influenced flavor and overall acceptability (p<0.05). T1 samples containing synthetic and natural nitrites showed the highest redness values. Spinach juice negatively affected volatile basic nitrogen; however, thiobarbituric acid reactive substance values of T1 and T3 were similar to those of controls (+) (p>0.05). Residual nitrite content decreased with decreasing synthetic nitrite levels. T1 and control samples showed no significant differences in overall acceptability (p>0.05).

Conclusion

Thus, combined synthetic and natural nitrites improved the quality of cured pork loin.

Effects of Pre-cooking Methods on Quality Characteristics of Reheated Marinated Pork Loin

We evaluated the effects of pre-cooking methods on the quality of reheated marinated pork loin. Frozen marinated pork loins cooked using various methods (boiling, grilling, pan frying, infrared cooking, and superheated steam cooking) were reheated in a microwave, and their pH, color, cooking loss, re-heating loss, total loss, thiobarbituric acid reactive substance (TBARS) value, sensory properties, and shear force were determined. Although all parameters varied with different cooking methods, lightness values and TBARS values showed the tendency to decrease and increase, respectively, after reheating. Superheated steam-cooked samples showed the lowest values of cooking loss, total loss, TBARS value, and shear force (p<0.05) and the highest lightness, redness, and yellowssness values and juiciness, chewiness, and overall acceptability scores (p<0.05). These results show that pre-cooking with superheated steam maintains the quality characteristics of marinated pork loin upon reheating. Therefore, pre-cooking with superheated steam may be beneficial for the commercial distribution of frozen cooked marinated pork loin.

Effects of Replacing Pork with Tuna Levels on the Quality Characteristics of Frankfurters

The aim of this study was to evaluate the effects of pork and tuna levels on the quality characteristics of frankfurters and to establish a suitable percentage of added tuna. The levels of pork meat (PM) and yellow-fin tuna (YFT) in the test frankfurters were as follows: 100% PM (control), 90% PM+10% YFT (T1), 80% PM+20% YFT (T2), 70% PM+30% YFT (T3), 60% PM+40% YFT (T4), and 50% PM+50% YFT (T5). The pH of the frankfurter batters significantly decreased with increasing tuna levels, because the pH of the tuna is lower than that of the pork. The water holding capacity did not differ significantly in frankfurters containing up to 30% tuna, whereas that of the 40% tuna-containing frankfurter was significantly lower than the control. Cooking loss did not differ significantly. At up to 10% tuna, apparent viscosity did not differ significantly, whereas at 20% tuna, it was significantly lower than the control. Fat separation and total expressible fluid separation at up to 30% tuna did not differ from the control; however, when more than 30% was added, higher losses were observed. The hardness of frankfurters containing more than 40% tuna was lower than that of the control, but there was no significant difference in springiness. The overall acceptability of frankfurters manufactured with up to 30% tuna did not differ significantly from the control. These results suggest that the addition of 30% tuna does not affect the quality of frankfurters made from pork.

The Ratios of Pre-emulsified Duck Skin for Optimized Processing of Restructured Ham

The purpose of this study was to investigate the quality of duck ham formulated with duck skin through the pre-emulsification process. The experiments to investigate the quality characteristics of duck ham were carried out to measure proximate composition, cooking loss, emulsion stability, pH, color, texture profile analysis, apparent viscosity, and sensory characteristics. Duck ham was prepared with various ratios of duck skin in pre-emulsion as follows: Control (duct skin 30%), T1 (duck skin 20% + pre-emulsified duck skin 10%), T2 (duck skin 15% + pre-emulsified duck skin 15%), T3 (duck skin 10% + pre-emulsified duck skin 20%), and T4 (pre-emulsified duck skin 30%). As the ratio of duck skin to pre-emulsified skin changed, the quality of duck ham in terms of moisture content, fat content, cooking loss, emulsion stability, lightness, textural analysis, apparent viscosity, and overall acceptability changed. The moisture content of T2 was the highest (p<0.05) and that of the control and T4 was the lowest (p<0.05). The fat content of control was higher than all treatments (p<0.05). T2 had the lowest values in cooking loss, total expressible fluid, fat separation, hardness, springiness, and gumminess (p<0.05). The score of overall acceptability of all treatments with pre-emulsified skin was higher than control (p<0.05). Therefore, the pre-emulsification process can improve the quality characteristics of duck ham and 1:1 ratio of duck skin and pre-emulsified skin was the proper ratio to improve the quality characteristics of duck ham.

Effect of natural pre-converted nitrite sources on color development in raw and cooked pork sausage

Objective

The effect of pre-converted nitrites from natural sources (spinach, lettuce, celery, and red beet) on color development in raw and cooked pork sausage was investigated in this study.

Methods

The pork sausage was manufactured with six treatments: NC (negative control, nitrite free), PC (positive control, 150 ppm sodium nitrite), FS (3.0% fermented spinach extracts), FL (3.0% fermented lettuce extracts), FC (3.0% fermented celery extracts), and FR (3.0% fermented red beet extracts).

Results

The pH value of the pre-converted nitrites groups was lower than those treated with 150 ppm sodium nitrite (p<0.05). The color values of raw and cooked pork sausage added with pre-converted nitrite showed slightly lower and/or similar lightness, lower redness, and higher yellowness values than PC. Color development (redness values) of cooked samples added with FS was higher than those of the NC and other treatments (FL, FC, and FR). Additionally, treatments with FS and FL were most effective for reducing thiobarbituric acid reactive substances and volatile basic nitrogen than the NC.

Conclusion

Effects of natural nitrites from fermented vegetables on shelf stability of raw and cooked pork sausages were investigated. Fermented spinach extract was much more useful for maintaining the color development, but also inhibiting lipid and protein oxidation of cooked pork sausage. Therefore, pre-converted nitrite from spinach as a natural nitrite could be used as another natural nitrite source for making processed meat products.

Optimization of Replacing Pork Meat with Yellow Worm (Tenebrio molitor L.) for Frankfurters

The effects of replacing pork meat with yellow mealworms on the physicochemical properties and sensory characteristics of frankfurters were investigated in this study. The control (50% pork ham), T1 (45% pork ham + 5% yellow mealworm), T2 (40% pork ham + 10% yellow mealworm), T3 (35% pork ham + 15% yellow mealworm), T4 (30% pork ham + 20% yellow mealworm), T5 (25% pork ham + 25% yellow mealworm), and T6 (20% pork ham + 30% yellow mealworm) were prepared, replacing lean pork meat with yellow mealworm. The moisture content, lightness, sarcoplasmic protein solubility, hardness, gumminess, chewiness, and apparent viscosity of frankfurters with yellow mealworm were lower than those of the control (p<0.05), whereas the content of protein and ash, pH, and yellowness of frankfurters with yellow mealworm were higher than those of the control (p<0.05). The fat content of frankfurters in T1 (p<0.05) was the highest, and the fat content of treatments decreased with increasing yellow mealworm concentrations (p<0.05). Frankfurters with increasing yellow mealworm concentrations had lower color, flavor, off-flavor, and juiciness scores. The overall acceptability was not significantly different in the control, T1, and T2 (p>0.05). Thus, the results of this study showed that replacing lean pork meat with up to 10% yellow mealworm successfully maintained the quality of frankfurters at a level similar to that of the regular control frankfurters.

Quality Characteristics of Tteokgalbi with Black Rice Bran and Organic Acid to Substitute Synthetic Caramel Colorant

This study aimed to evaluate the quality characteristics of Tteokgalbi with 1% (w/w) black rice bran only (T1), or with black rice bran and one of the following four types of organic acid: ascorbic acid (T2), citric acid (T3), tartaric acid (T4), or maleic acid (T5) as a substitute for caramel colorant. Tteokgalbi with only black rice bran showed the highest (p<0.05) values of moisture content and water holding capacity (WHC), while there were no significant differences in protein content, fat content, ash content, and thiobarbituric acid reactive substance (TBARS) values in treatments and controls (p>0.05). All the treated samples with any one of the four organic acids showed lower pH than controls (p<0.05). The lightness and redness of Tteokgalbi treated with any one of the four organic acids and black rice bran were higher than those of T1. The volatile basic nitrogen (VBN) values of T4 and T5 were higher than those of the other treatments (p<0.05). With regards to sensory characteristics, T1 and T2 showed overall acceptability similar to that of the controls (p>0.05). The results reported in this study show that Tteokgalbi with black rice bran and any one of the four organic acids listed above not only improved quality characteristics in cooking loss, WHC, lipid oxidation but also could successfully replace the synthetic caramel colorant. Overall, the most satisfactory results were obtained by adding black rice bran and ascorbic acid.

Effect of fermented red beet extracts on the shelf stability of low-salt frankfurters

The effect of fermented red beet (FRB) on shelf-life of low-salt frankfurters stored for 4 weeks was investigated. The pH, volatile basic nitrogen (VBN), lightness, and yellowness of frankfurters decreased with increasing levels of FRB, whereas the redness of frankfurters increased with increasing levels of FRB. The VBN, thiobarbituric acid reactive substance values, total viable count, and redness of all treatments decreased with increasing period of refrigeration storage. The appearance, color, and juiciness scores of the control and treatments decreased with increasing period of refrigeration storage. However, there was no significant (p > 0.05) difference among the treatments except for the color of T3 (3.0% FRB) and juiciness of T4 (5.0% FRB). The flavor, tenderness, and overall acceptability scores of all the treatments decreased with increasing storage periods. These results demonstrated that FRB can be added to low-salt frankfurters to maintain their qualities and extend the shelf-life of refrigerated storage.

Effects of gamma-ray, electron-beam, and X-ray irradiation on physicochemical properties of heat-induced gel prepared with salt-soluble pork protein

The objective of this study was to investigate the physicochemical and textural properties of heat-induced gels prepared with pork muscles irradiated with gamma rays, electron beams, and X-rays. Pork muscles were irradiated at 5 kGy using the different irradiation sources, and heat-induced gels were prepared from the irradiated pork muscles at a protein concentration of 5 mg/mL. Each irradiation treatment produced lower water-holding capacity, protein solubility, apparent viscosity, hardness, springiness, cohesiveness, gumminess, and chewiness than the control gel prepared with non-irradiated pork muscle (P < 0.05). In addition, gamma irradiation was more influential than electron or X-ray irradiation on the negative impacts on water-holding capacity and texture of heat-induced gels. Therefore, this study suggests that the irradiation source could be one of the significant factors affecting gelling properties of irradiated meat.

Effects of Pre-Converted Nitrite from Red Beet and Ascorbic Acid on Quality Characteristics in Meat Emulsions

We investigated the effects of fermented red beet extract and ascorbic acid on color development in meat emulsions. The pH of meat emulsions containing red beet extract decreased with an increase in the amount of extract added. The redness of the treated meat emulsions was higher than that of the control with no added nitrite or fermented red beet extract (p<0.05), though the redness of the meat emulsions treated with fermented red beet extract only was lower than in that treated with both fermented red beet extract and ascorbic acid (p<0.05). The highest VBN, TBARS, and total viable count values were observed in the control, and these values in the meat emulsions treated with fermented red beet extract were higher than in that treated with both fermented red beet extract and ascorbic acid (p<0.05). E. coli and coliform bacteria were not found in any of the meat emulsions tested. Treatment T2, containing nitrite and ascorbic acid, had the highest overall acceptability score (p<0.05); however, there was no significant difference between the T2 treatment and the T6 treatment, which contained 10% pre-converted nitrite from red beet extract and 0.05% ascorbic acid (p>0.05). The residual nitrite content of the meat emulsions treated with ascorbic acid was lower than in those treated without ascorbic acid (p<0.05). Thus, the combination of fermented red beet extract and ascorbic acid could be a viable alternative to synthetic nitrite for the stability of color development in meat emulsions.

Effect of Fermented Spinach as Sources of Pre-Converted Nitrite on Color Development of Cured Pork Loin

The effect of fermented spinach extracts on color development in cured meats was investigated in this study. The pH values of raw cured meats without addition of fermented spinach extract or nitrite (negative control) were higher (p<0.05) than those added with fermented spinach extract. The pH values of raw and cooked cured meats in treatment groups were decreased with increasing addition levels of fermented spinach extract. The lightness and yellowness values of raw cured meats formulated with fermented spinach extract were higher (p<0.05) than those of the control groups (both positive and negative controls). The redness values of cooked cured meats were increased with increasing fermented spinach extract levels, whereas the yellowness values of cooked cured meats were decreased with increasing levels of fermented spinach extract. The lowest volatile basic nitrogen (VBN) and thiobarbituric acid reactive substances (TBARS) values were observed in the positive control group with addition of nitrite. TBARS values of cured meats added with fermented spinach extract were decreased with increasing levels of fermented spinach extract and VBN values of curing meat with 30% fermented spinach extract was lower than the other treatments. Total viable bacterial counts in cured meats added with fermented spinach extract ranged from 0.34-1.01 Log CFU/g. E. coli and coliform bacteria were not observed in any of the cured meats treated with fermented spinach extracts or nitrite. Residual nitrite contents in treatment groups were increased with increasing levels of fermented spinach extract added. These results demonstrated that fermented spinach could be added to meat products to improve own curing characteristics.

Quality and Sensory Characteristics of Reduced-fat Chicken Patties with Pork Back Fat Replaced by Dietary Fiber from Wheat Sprout

The effects of reducing pork fat levels from 20% to 15% or 10% by partially substituting pork back fat with wheat sprout fiber in reduced-fat chicken patties were investigated. Approximate composition, energy value, pH, color, cooking loss, reduction in diameter, reduction in thickness, shear force, and sensory properties were determined. Moisture content, ash contents, yellowness of uncooked and cooked reduced-fat chicken patties with wheat sprout were higher than those in the control, while displaying fat content, calorie content, and pH of uncooked and cooked lower in reduced-fat chicken patties than in the control. Cooking loss, reduction in diameter, and reduction in thickness were the highest in the reduced-fat chicken patties with 10% fat level. Cooking loss, reduction in diameter, and reduction in thickness were decreased when fat levels and wheat sprout levels were increased. Control samples without wheat sprout dietary fiber had significantly (p<0.05) higher color and flavor scores compared to reduced-fat chicken patties containing wheat sprout dietary fiber. The overall acceptability of the control and treatment with 15% fat and 2% wheat sprout dietary fiber (T3) was the highest. Therefore, 15% fat level in reduced-fat chicken patties with the addition of 2% wheat sprout dietary fiber can be used to improve the quality and sensory characteristics of regular-fat chicken patties containing 20% fat level.

Replacement of Pork Meat with Pork Head Meat for Frankfurters

The effect of reducing pork meat concentrations from 50% to 30% and replacing it with up to 20% pork head meat on chemical composition, cooking characteristics, physicochemical and textural properties, apparent viscosity, and sensory characteristics of frankfurters was determined. The highest moisture content in frankfurters was found in the control and T1 (frankfurter with 45% pork meat + 5% pork head). Protein and fat contents in frankfurters with pork head meat added were significantly (p<0.05) higher than those in the control. When the concentration of pork head meat was increased from 0% to 20%, cooking loss, total expressible fluid separation, fat separation, and pH of frankfurters were increased, while the lightness, redness, yellowness, and apparent viscosity of frankfurters were decreased. Ash contents, cohesiveness, color, and tenderness of sensory characteristics of frankfurters added with different amounts of pork meat or pork head meat were not significantly (p>0.05) different from those of the control or there treatments. Frankfurters in T4 (frankfurter with 30% pork meat + 20% pork head) had the lowest (p<0.05) hardness and gumminess. The hardness and gumminess of frankfurters in other treatments were not significantly different (p>0.05) from that in the control. Frankfurters with higher pork head meat concentrations had lower flavor, juiciness, and overall acceptability scores. Therefore, replacing pork meat with pork head meat in the formulation could successfully produce results similar to those of control frankfurters. The best results were obtained when 10% pork head meat was used to replace pork meat.

Effects of Various Salts on Physicochemical Properties and Sensory Characteristics of Cured Meat

This study was carried out to investigate the effects of refined, solar, and bamboo salt on the physico-chemical properties and sensory characteristics of cured pork loin. Moisture, protein, fat, and ash content, lightness, yellowness, cooking yield, and color, juiciness, and tenderness of sensory properties on curing pork loin exhibited no significant differences regardless of the nature of salts. The pH of raw and cooked cured pork loin with added bamboo salt was higher that of other salt treatments. However, the cooking loss, and Warner-Bratzler shear force of cured pork loin with added refined salt was lower than those of solar and bamboo salt pork loins cured. The flavor and overall acceptability scores of treatments with refined salt was higher than those of solar and bamboo salt treatments. The unique flavor of bamboo salt can render it as a functional material for marinating meat products. In addition, the results of this study reveal potential use of bamboo salt in meat curing.

Comparative Study on the Effects of Boiling, Steaming, Grilling, Microwaving and Superheated Steaming on Quality Characteristics of Marinated Chicken Steak

The effects of five different cooking methods (boiling, steaming, grilling, microwaving, and superheated steaming) on proximate composition, pH, color, cooking loss, textural properties, and sensory characteristics of chicken steak were studied. Moisture content and lightness value (L*-value) were higher in superheated steam cooked chicken steak than that of the other cooking treatments such as boiling, steaming, grilling and microwaving cooking (p<0.05), whereas protein content, redness value (a*-value), hardness, gumminess, and chewiness of superheated steam cooked chicken steak was lower than that in the other cooking treatments (p<0.05). Fat content and ash content, springiness, and cohesiveness were not significantly different among the chicken steak cooked using various methods (p>0.05). Among the sensory characteristics, tenderness score, juiciness score and overall acceptability score were the highest for the superheated steam samples (p<0.05), whereas no difference in flavor scores were observed among the other treatments (p>0.05). These results show that marinated chicken steak treated with superheated steam in a preheated 250℃ oven and 380℃ steam for 5 min until core temperature reached 75℃ improved the quality characteristics and sensory properties the best. Therefore, superheated steam was useful to improve cooked chicken steak.

Effects of Edible Seaweed on Physicochemical and Sensory Characteristics of Reduced-salt Frankfurters

The effects of sea tangle, sea mustard, hijiki, and glasswort were investigated based on the proximate composition, salinity, cooking loss, emulsion stability, pH, color, texture profile analysis, apparent viscosity, and sensory characteristics of reduced-salt (NaCl) meat batter and frankfurters. The moisture content, salinity, lightness of the meat batter and frankfurter, hardness, gumminess, and chewiness of the reduced-salt frankfurters with sea weeds were lower than the control without seaweed (p<0.05). The protein content, springiness, and cohesiveness of the reduced-salt frankfurters were not significantly different among the treatments (p>0.05). The moisture content, salinity, cooking loss, lightness, redness, hardness, gumminess, and chewiness of treatments with sea tangle and with sea mustard were lower than the control (p<0.05). Among the sensory traits, color was highest in the control (p<0.05). The flavor was also highest in the control. The treatments with sea tangle and with sea mustard samples had high tenderness, juiciness, and overall acceptability scores similar to the control (p<0.05). The results of this study show that the combination of low-salt and seaweed in the formulation successfully improved reduced-salt frankfurters, improving sensory characteristics to levels similar to the regular salt control (1.5%).

Optimization for Reduced-Fat / Low-NaCl Meat Emulsion Systems with Sea Mustard (Undaria pinnatifida) and Phosphate

The effects of reducing fat levels from 30% to 20% and salt concentrations from 1.5% to 1.0% by partially substituting incorporated phosphate and sea mustard were investigated based on physicochemical properties of reduced-fat / low-NaCl meat emulsion systems. Cooking loss and emulsion stability, hardness, springiness, and cohesiveness for reduced-fat / low-NaCl meat emulsion systems with 20% pork back fat and 1.2% sodium chloride samples with incorporation of phosphate and sea mustard were similar to the control with 30% pork back fat and 1.5% sodium chloride. Results showed that reduced-fat / low-NaCl meat emulsion system samples containing phosphate and sea mustard had higher apparent viscosity. The results of this study show that the incorporation of phosphate and sea mustard in the formulation will successfully reduce fat and salt in the final meat products.

Effect of Dietary Fiber Extracted from Algelica keiskei Koidz on the Quality Characteristics of Chicken Patties

In this study, we evaluated the effects of dietary fiber extracted from Algelica keiskei Koidz on the chemical composition, cooking characteristics, and sensory properties of chicken patties. The chicken patties with Algelica keiskei Koidz dietary fiber had significantly higher moisture and ash content, and yellowness than the control sample (p<0.05). Energy value, cooking loss, reduction in diameter, reduction in thickness, lightness, redness, hardness, cohesiveness, gumminess, and chewiness of the control samples was significantly higher than chicken patties with Algelica keiskei Koidz dietary fiber (p<0.05). The sensory evaluation indicated that the greatest overall acceptability in chicken patties was achieved at Algelica keiskei Koidz dietary fiber levels of 1% and 2%. Chicken patties supplemented with 2% Algelica keiskei Koidz dietary fiber had improved quality characteristics.

Changes in Ultrastructure and Sensory Characteristics on Electro-magnetic and Air Blast Freezing of Beef during Frozen Storage

The ultrastructure in the beef muscle of the electro-magnetic resonance and air blast freezing during the frozen storage, and the changes in the quality characteristics after thawing were evaluated. The size of ice crystal was small and evenly formed in the initial freezing period, and it showed that the size was increased as the storage period was elapsed (p<0.05). The beef stored by the electro-magnetic resonance freezing showed the size of ice crystal with a lower rate of increase than the air blast freezing during the frozen storage. The thawing loss of beef stored by the electro-magnetic resonance freezing was significantly lower than the air blast freezing during frozen storage (p<0.05), and it showed that the thawing loss of the round was higher than the loin. Water holding capacity decreased as the storage period became longer while the electro-magnetic resonance freezing was higher than the air blast on 8 month (p<0.05). As a result of sensory evaluation, the beef stored by the electro-magnetic resonance freezing did not show the difference until 4 months, and it showed higher acceptability in comparison with the beef stored by the air blast freezing. Thus, it is considered that the freezing method has an effect on the change in the ultrastructure and quality characteristics of the beef.

Combined effects of presalted prerigor and postrigor batter mixtures on chicken breast gelation

We examined the combined effects of prerigor and postrigor batter mixtures on protein gelation. The postrigor batter was prepared with 2% salt, whereas the prerigor meat at 5 min postmortem was used to prepare postrigor batters at different salt levels. For 5 treatments, prerigor batters were mixed with postrigor batter that had 2% salt (control) as follows: T1: ground presalted (1%) hot-boned breast with 1% salt for 50% total batch; T2: ground presalted (2%) hot-boned breast for 50% total batch; T3: ground presalted (3%) hot-boned breast for 30% total batch that was mixed with cold-boned batter for 50% total batch; T4: ground presalted (4%) hot-boned breast for 25% total batch that was mixed with cold-boned batter for 50% total batch; and T5: ground presalted (5%) hot-boned breast for 20% total batch that was mixed with cold-boned batter for 50% total batch. Treatments with both presalted prerigor and postrigor muscle showed less cooking loss and lower emulsion stability than the control, except T5. The protein solubility and apparent viscosity of the control was the lowest. Thus, presalted hot-boned muscle combined with cold-boned muscle positively affected physicochemical properties.