Jeong-Seok Cho

Image analysis to evaluate the browning degree of banana (Musa spp.) peel

Image analysis was applied to examine banana peel browning. The banana samples were divided into 3 treatment groups: no treatment and normal packaging (Cont); CO2 gas exchange packaging (CO); normal packaging with an ethylene generator (ET). We confirmed that the browning of banana peels developed more quickly in the CO group than the other groups based on sensory test and enzyme assay. The G (green) and CIE L(∗), a(∗), and b(∗) values obtained from the image analysis sharply increased or decreased in the CO group. And these colour values showed high correlation coefficients (>0.9) with the sensory test results. CIE L(∗)a(∗)b(∗) values using a colorimeter also showed high correlation coefficients but comparatively lower than those of image analysis. Based on this analysis, browning of the banana occurred more quickly for CO2 gas exchange packaging, and image analysis can be used to evaluate the browning of banana peels.

Qualitative properties of roasting defect beans and development of its classification methods by hyperspectral imaging technology

Qualitative properties of roasting defect coffee beans and their classification methods were studied using hyperspectral imaging (HSI). The roasting defect beans were divided into 5 groups: medium roasting (Cont), under developed (RD-1), over roasting (RD-2), interior under developed (RD-3), and interior scorching (RD-4). The following qualitative properties were assayed: browning index (BI), moisture content (MC), chlorogenic acid (CA), trigonelline (TG), and caffeine (CF) content. Their HSI spectra (1000-1700nm) were also analysed to develop the classification methods of roasting defect beans. RD-2 showed the highest BI and the lowest MC, CA, and TG content. The accuracy of classification model of partial least-squares discriminant was 86.2%. The most powerful wavelength to classify the defective beans was approximately 1420nm (related to OH bond). The HSI reflectance values at 1420nm showed similar tendency with MC, enabling the use of this technology to classify the roasting defect beans.

Comparison of image analysis methods to evaluate the degree of browning of fresh-cut lettuce

Digital image analysis was used to detect changes in browning of fresh-cut lettuce. Fresh-cut lettuce was divided into the 4 treatment groups of dipping in distilled water (control group); ultrasound treatment for 90 s in distilled water (US); blanching for 90 s at 45°C (BC); and blanching after ultrasound treatment (US+BC). The degree of browning was measured using image analysis, colorimetry, spectrophotometry, and visual assessment. Using image analysis, the US+BC treatment group showed the smallest browning area and lowest b* value. Correlation between visual assessment and image analysis for evaluation of the area of browning was the highest (0.9592), followed by the b* value of image analysis (0.9527). The lowest correlation coefficient (0.6962) was observed between visual assessment and the b* value using colorimetry. Image analysis can be used as a method for evaluating browning in fresh-cut lettuce.

Effect of sweeteners on the quality characteristics of ginger (Zingiber officinale Rosc) JungKwa

In this study the physicochemical properties and antioxidant capacities of ginger (Zingiber officinale Rosc) Jungkwa with different kinds of sweeteners were determined. Jungkwa made with different sugars (sugar, xylitol, honey or oligosaccharides) were compared in aspect of physiochemical properties, antioxidant activities, total phenolic contents and sensory evaluation. Moisture contents Jungkwa treated different kinds of oligosaccarides showed highest value, in the order of honey, xylitol and sugar. L* value of Jungkwa treated with xylitol was the highest, a* value of Jungkwa treated with honey, sugar JungKwa were higher then others. Free sugar contents of Jungkwa treated with sugar showed the highest value in sucrose, glucose and galactose. Jungkwa with xylitol showed lowest value in all free sugar contents. Hardness and chewiness of Jungkwa treated with xylitol showed the highest value. The antioxidant activity measured by DPPH and ABTS radical scavenging activity and total penolic content were the highest in Jungkwa treated with honey, followed by Jungkwa treated with xylitol, oligosaccharides and sugar. Appearance and color of oligosaccarides and honey treated Jungkwa were preferred. In ginger taste, sweetness, chewiness were highest in sugar treated Jungkwa (not significant difference in treatments). As a result, honey treated Jungkwa has higher antioxidant activity and quality than other sugar treatments.

Evaluation of the Quality Characteristics in Omija (Schizandra chinensis Baillon) Powder Tea

Food and Bio-industry Research Institute, Kyungpook National UniversityAbstract The purpose of this study was to evaluate the quality characteristics in different types of Omija (Schizandrachinensis Baillon) powder tea. Raw Omija was prepared in three ways: 1) freeze-dried powder of whole Omija (FD), 2)freeze-dried powder of pressed Omija juice (PF), and 3) granules of pressed Omija juice (PG). Dried Omija was extractedand prepared in three ways: 4) freeze-dried powder (EF), 5) granules (EG), and 6) spray-dried powder (ES). The totalsoluble solid contents and turbidity were higher in PG, EG, and ES than those in other samples. L* value, pH, andreducing sugar contents were higher in PG and EG than those in other samples. Finally, a* value, b* value, total phenoliccompounds contents, antioxidant activities, total anthocyanin contents, and schizandrin contents were lower in PG and EGthan those in other samples. These results show that FD, PF, EF, and ES are more effective in outstanding redness andantioxidant activities compared to other Omija powder products.Keywords: Omija (Schizandrin chinensis Baillon), powder tea, quality characteristics, anthocyanin, schizandrin