Calibrated Photo-Stimulated Luminescence and E-Sensing Analyses
Discriminate Korean Citrus Fruits Treated with Electron Beam
Dong U. Ahn
Received: 23 January 2018 /Accepted: 14 May 2018
Springer Science+Business Media, LLC, part of Springer Nature 2018
Korean citrus fruits (Jinjihyang and Chunggyun) were treated with electron beam (e-beam) at phytosanitary irradiation doses of 0,
0.4, and 1 kGy, and their irradiation status was screened after storage for 0, 10, and 20 days. Because of the inherent limitations of
photo-stimulated luminescence (PSL), the first PSL measurement (PSL
) was not sufficient to distinguish the irradiated samples
from the non-irradiated controls. The calibrated PSL approach clearly distinguished the e-beam-irradiated samples from the
control based on PSL ratio (PSL
): > 10, non-irradiated; < 10, irradiated. In addition to PSL, electronic-sensing techniques
(E-tongue and E-nose) clearly discriminated the irradiated Jinjihyang and Chunggyun fruits samples from their non-irradiated
counterparts based on principal component analysis of taste attributes and volatile patterns. The quantitative analysis of volatile in
irradiated citrus fruits showed that limonene was present at the highest concentration among all the volatiles from peels, and
significant dose-dependent decreases were observed in both citrus varieties (p < 0.05). Limonene from the irradiated pulps
showed a dose-dependent increase on day 0.
Citrus fruits are classified as a genus in the family Rutaceae
and are among the most in-demand and important crops.
Citrus fruits are widely consumed by people worldwide be-
cause of their unique characteristics such as pleasant aroma
and high vitamin C, antioxidants, and mineral content (partic-
ularly phosphorous, magnesium, copper, and potassium).
Moreover, citrus fruits contain flavonoids, limonoids, pectins,
coumarins, and carotenoids that have several health benefits
and biological functions in the human body (Yao et al. 2004;
Zou et al. 2016). Jinjihyang (Citrus unshiu Marc. × C. sinensis
Osbeck × C. unshiu)andChunggyun (Citrus unshiu Marc. ×
C. sinensis Osbeck) are popular cultivars in the Republic of
Korea. These varieties are famous because of their appealing
attributes, such as soft fruit with high-quality juice, ease of
pealing because of their thin rind, and strong aromatic scent
resembling orange (Koh 2007;HongandKim2016).
Moreover, Satsuma mandarin (Citrus unshiu Marc.) is also
included among the most economical citrus crops owing to
appealing attributes of high fruit production, processed prod-
uct variegation, and higher nutritional significance. The major
cultivar of this group in Korea is named as Miyagawa
wase, and it exhibits unique properties of genetic sterility,
polyembryony, and long juvenility (Al Bachchu et al.
2011). Many published reports have reported on the anti-
microbial properties and chemical compositions of various
citrus species grown in Korea Citrus reticulata, C.
bergamia, C. hallabong,andC. tamurana (Choi and
Sawamura 2001; Choi 2003; Sanguinetti et al., 2006;
Sawamura et al. 2004; Song et al. 2006).
Food irradiation is now approved for commercial purposes
in more than 55 countries. A minimum quarantine treatment
dose of 0.4 kGy was declared by the Animal and Plant Health
Inspection Service of the US Department of Agriculture for
fresh fruits intended for export to the USA (APHIS 2012).
Many previously published studies demonstrated that low-
* Joong-Ho Kwon
School of Food Science & Biotechnology, Kyungpook National
University, Daegu 41566, South Korea
Department of Food Science and Technology and BK 21 plus
Program, Graduate School of Chonnam National University,
Gwangju 61186, South Korea
Gangneung-Wonju National University,
Wonju-si, Gangwon-do 26403, South Korea
Department of Animal Science, Iowa State University,
Ames, IA 50011-3150, USA
Food Analytical Methods