ABSTRACT
OBJECTIVES: To assess the validity and reliability of the Korean version of the reflux symptom score (K-RSS). MATERIALS AND METHODS: The English version of the RSS was translated into Korean and completed by 77 people (44 and 33 people in the patient group and control group, respectively). They completed the K-RSS (K-RSS-1) and reflux symptom index (RSI) questionnaires and answered questions about age, sex, underlying disease, smoking history, and alcohol and coffee consumption. They completed the K-RSS once more (K-RSS-2) after 1 - 2 weeks. Internal consistency was evaluated using Cronbach's α and test-retest reliability using the intraclass correlation coefficient (ICC). External validity was evaluated using the Spearman rank test between the RSI and K-RSS. The Mann-Whitney U test was used to assess internal validity by comparing the K-RSS-1 scores between the patient and control groups. RESULTS: The most common symptoms were globus sensation, throat clearing, and throat pain. The K-RSS reported high internal consistency (α = 0.894). The ICC for the total score was 0.883, indicating excellent test-retest reliability. According to the Spearman analysis, there was a significant correlation between the total score of the K-RSS and that of the RSI (rs = 0.902; P < 0.001), demonstrating strong external validity. Furthermore, the patient group showed significantly higher values than the control group in all K-RSS scores, suggesting high internal validity. CONCLUSION: The K-RSS is a patient-reported outcome questionnaire with excellent criterion-referenced validity and ideal reliability.
ABSTRACT
Coffee can be blended to create a variety of products to meet consumer's needs. In order to uncover the blending effect of coffee beans, we performed an experiment using principal component analysis (PCA). Twelve varieties of green beans were tested in 11 experimental groups, and the volatile compounds of the beans were analyzed. A total of 41 volatile compounds were identified. PCA was performed on 13 compounds that had a low odor threshold value or a high concentration among the identified compounds. PCA of total volatile compounds showed that principal component (PC) 1 and PC2 were extracted within 80% cumulative dispersion level. In PC1 and PC2, furfuryl alcohol and formic acid ethyl ester showed the greatest positive correlation coefficients among all the volatile compounds. The largest negative correlation coefficients in PC1 and PC2 were 4-hydroxy-2-butanone and 3-(ethylthio)propanal, respectively. Using PCA of the major volatile compounds in coffee, propanal and 1-methylpyrrole were found to have the largest positive correlation coefficients in PC1 and PC2, respectively. In the score plot of the major volatile components, 4 kinds of blended coffee were closely grouped, therefore showing similar aroma qualities. However, 5 kinds of other blended coffees showed a positive correlation with PC2. This is probably due to 3-(ethylthio)propanal acting as a specific value. The application of statistical methods to blended coffee allows for logical and systematic data analysis of data and may be used as a basis for quality evaluation.
