Rapid detection of adulterated peony seed oil by electronic nose
Revised: 12 March 2018 / Accepted: 18 March 2018 / Published online: 27 April 2018
Ó Association of Food Scientists & Technologists (India) 2018
Abstract Peony seed oil has recently been introduced as a
high-quality food oil. Because the high price of peony seed
oil may tempt unscrupulous merchants to dilute it with
cheaper substitutes, a rapid detection method for likely
adulterants is required. In this study, the fatty acid com-
position of peony seed oil and four less expensive edible
oils (soybean oil, corn oil, sunﬂower oil, and rapeseed oil)
were measured by gas chromatography mass spectrometry.
Peony oil adulterated by other edible oils was assessed
using iodine values to estimate the extent of adulteration.
Adulteration was also measured using an electronic nose
(E-nose) combined with principal component analysis
(PCA) or linear discriminant analysis (LDA). Results
indicated that peony seed oil was highly enriched in a-
linolenic acid. Although the iodine value can be used to
detect some adulterants by measuring unsaturation, it was
not able to detect all four potential adulterants. In contrast,
the E-nose can rapidly identify adulterated peony seed oil
by sampling vapor. Data analyses using PCA and LDA
show that LDA more effectively clusters the data, dis-
criminates between pure and adulterated oil, and can detect
adulteration at the 10% level. E-nose combined with LDA
suitable for detection of peony seed oil adulteration.
Keywords Peony seed oil Á Adulteration Á GC–MS Á
Tree peony (Paeonia section Moutan DC.), a well-known
woody ornamental indigenous to China, has recently been
exploited as an oilseed plant (Li 2011; Xue et al. 2015).
The oil content of peony’s black elliptical seeds exceeds
20%, and more than 90% of the oil is unsaturated fatty
acids (UFA). Surprisingly, a-linolenic acid (ALA), a type
of omega-3 fatty acid, constitutes up to 40% of the oil.
ALA cannot be synthesized in the human body but it is
indispensable. ALA provides signiﬁcant health beneﬁts due
to its hypolipidemic effects and antioxidant properties; it is
also protective against rheumatoid arthritis, stroke, fatal
ischemic heart disease, and some forms of cancer (Connor
1999; Han et al. 2016; Su et al. 2016; Wang et al. 2015).
Although ALA is present in other edible oils, it is relatively
less abundant. The ALA content of rapeseed oil is 9.46%,
sunﬂower oil is 1%, olive oil is 0.72%, sesame oil is 0.29%,
and camellia oil less than 0.27%. Some researchers suggest
that the nutritional quality of peony seed oil is superior to
olive oil and camellia oil (Xie et al. 2013; Rinco
et al. 2016; Samman et al. 2008; Wang and Yuan 2015). In
2011, the National Health and Family Planning Commis-
sion approved peony seed oil as a new food resource for the
marketplace in China.
Peony seed oil adulteration has rarely been reported, but
other high-quality oils such as olive oil, camellia seed oil,
and ﬂaxseed oil are often illicitly blended with inexpensive
oils to increase proﬁts (Dourtoglou et al. 2003; Xie et al.
2013; Sun et al. 2015). Adulteration of edible oils not only
harms the interests of consumers, but may also harm their
health. Because peony seed oil commands a high price, a
strong incentive exists to dilute it with cheaper edible oils.
Oil adulteration is most commonly detected using spec-
troscopic and chromatographic methods, including near-
& Xingfeng Shao
Department of Food Science and Engineering, Ningbo
University, Ningbo, China
College of Food Science and Technology, Nanjing
Agricultural University, Nanjing, China
J Food Sci Technol (June 2018) 55(6):2152–2159