Mi-Seon Jeong

Microbiological and Physicochemical Quality Characterization of Commercial Red Pepper Powders

Ten commercially available red pepper powders were investigated for their hygienic quality (total aerobic count, yeasts and molds, and coliforms) and physicochemical properties (moisture content, pH, Hunters color values, American Spice Trade Association (ASTA) color and particle size). Microbial analysis resulted in 10 3 -10 6 CFU/g of total aerobic count and same of yeasts & molds, where 2 samples were positive (10 3 CFU/g) for coliforms. The moisture contents (7.25% to 12.73%) were with in the range as described in the Korean Food Standards Codex. Noteworthy variations were observed in pH (4.97 to 5.15), Hunters ∆E values (47.19 to 58.04) and ASTA color values (89.31 to 98.61). Although the color differences were evident among the samples, but the Hunter values were not in good correlations with ASTA color values. The average particle sizes of the all samples were comparable ranging from 605 µm to 1251 µm with few exceptions. There was a great variation in the key quality attributes of commer- cially available red pepper powders that should be considered for their various uses in food products.

Monitoring of Commercial Red Pepper Powders for Their Irradiation Status

Ten commercially available red pepper powders were investigated using photostimulated-luminescence (PSL), thermoluminescence (TL) and electron spin resonance (ESR) analyses to confirm their irradiation status. The application of PSL, TL, and ESR analyses was also confirmed by in-house irradiation. In PSL-based screening, all samples gave negative photon counts (<700 PCs). The PSL calibration dose (1 kGy) showed a low sensitivity of 4 samples, while the others provided reliable screening results. TL glow curves demonstrated maximum peaks after 250 o C for the 6 samples; however 4 samples gave complex TL glow curves with maximum peaks in the range of 185-260 o C (radiation-specific), which could be the effect of an irradiated component in low concentration as the TL ratios of all samples were <0.1. Radiation-specific ESR features were absent in the all commercial samples. Variable irradiation detection properties were found; where the TL analysis showed the possible presence of an irradiated component in 4 samples requiring further monitoring and investigation.

Applicability of Irradiation Detection Techniques and Quality Characterization of Cinnamon Powders Available in the Korean Market

The market availability of irradiated products requires proper labeling to safeguard the consumer’s right of choice. Ten commercial cinnamon powders of different origins were investigated to confirm their irradiation history using photostimulated-luminescence, thermoluminescence, and electron spin resonance analyses. Photostimulated-luminescence analysis screened out one sample as an intermediate (700–5000 PCs) while all others were negative. Upon thermoluminescence analysis, two samples yielded weak but clear peaks in the temperature range of 150–250oC, showing the possibility of irradiation. The electron spin resonance analysis showed limited sensitivity for all the commercial samples with the absence of radiation-specific features. The applicability of these techniques was confirmed by analyzing the radiation-induced detection markers in the in-house irradiated samples. Hygienic quality parameters and physicochemical properties (moisture content, pH, Hunter’s color, and particle size) showed variable results which can affect the quality of end product and should be taken into serious considerations to ensure hygienic quality and practical applications of cinnamon powders.

Luminescence properties and compositions of contaminating inorganic minerals separated from gamma-irradiated fresh and white ginsengs from different areas

Gamma-irradiation (0-7 kGy) of ginseng is permitted in Korea for the purpose of microbial decontamination; with strict labeling, traceability and monitoring requirements. An identification study was conducted to determine the photostimulated-luminescence (PSL) and thermoluminescence (TL) properties of gamma-irradiated fresh and white ginsengs cultivated in different areas. Dosedependent PSL-based screening was possible for white ginseng samples; however, inappropriate results from non-irradiated fresh ginseng samples were obtained, showing intermediate (700 to 5,000) or positive (T2 >5,000, irradiated) PSL counts due to the abundance of minerals on the surfaces of the samples. TL analysis of separated minerals from all non-irradiated samples gave TL glow curves of low intensity with a maximum peak after 300℃. However, well-defined irradiation-specific (high intensity with a maximum peak at about 200℃) glow curves were observed for all the irradiated samples, regardless of their type and origins. TL ratios (first glow curve /second glow curve) were also determined to confirm the irradiated (>0.1) and non-irradiated (<0.1) results. SEM-EDX (scanning electron microscope-energy dispersive X-ray) and XRD (X-ray diffraction) spectroscopic analyses showed that feldspar and quartz minerals were the main source for the typical radiation-specific luminescence properties.

Study of Photo and Thermoluminescence Properties to Identify Irradiated Dried-Fishery Products

ABSTRACT Radiation-specific luminescence properties in irradiated dried-fishery products (pollack, little pollack, clams, and shrimp) were investigated at different dose levels (0–10 kGy). Photostimulated luminescence (PSL) analysis of whole samples was effective for dried clams and shrimp, while low PSL sensitivity was observed in dried pollack and little pollack. Thermoluminescence (TL) analysis was conducted after isolation of silicate minerals, in which the two methods of mineral isolation—density separation and acid hydrolysis—were compared. Irradiated samples were easily distinguishable through the strong TL glow curves, with maximum peaks in temperature range of 150–250°C. TL ratios (TL1/TL2) were < 0.1 for nonirradiated samples, while > 0.1 for irradiated. There was a clear effect of applied irradiation dose, with a negligible effect of the method used for mineral separation. The mineral composition showed that feldspar and quartz minerals were mainly responsible for the well-characterized luminescence behavior upon irradiation.