Cold pressed orange (Citrus sinensis) oil

Abstract

Citrus are is a member of the world’s major fruit crops that have economic value. Citrus fruits are accepted as a rich source of dietary fiber, vitamin C, and phytochemicals such as carotenoids, phenolics, and limonoids. The most popular varieties of the Citrus genus belonging to the Rutaceae family are lemon (Citrus limon), orange (Citrus sinensis), grapefruit (Citrus paradisi), tangerine (Citrus reticulata), and key lime (Citrus aurantifolia). Pretreatments such as enzyme application, steaming, microwave heating, and conventional roasting prior to cold pressing process have significant effects on oil yield, bioactive components (flavonoids, phenolic acids, tocols, and pigments), aromatics, and sensorial properties of obtained citrus seeds/or peel oils. The characteristics of bitter taste and distinct aroma in cold pressed citrus peel/or seed oils are the main reasons for not accepting them as edible oils. Recent studies have shown that the bitter taste could be removed by debittering enzymes or absorbent treatments. This chapter focuses on the possibility of oil extraction from orange oils using the cold press technique and discusses the physicochemical, compositional, and sensorial properties, bioactive and volatile compounds, and health-related claims of cold pressed orange oils. The usage and basic composition of oil-free meals gained after cold pressing, possible edible applications, and nonedible (personal care, cosmetic, pharmaceutical, and oleo chemistry) utilization of these citrus oils are also discussed.

Full text

Chapter 12
Cold pressed orange (Citrus sinensis)oil
Buket Aydeniz-Guneser
Department of Food Engineering, Engineering Faculty, Usak University, Usak, Turkey
Abbreviations list
B. cereus Bacillus cereus
BAH German Medicines Manufacturers’ Association
DSC differential scanning calorimeters
FAO food and agriculture organization
FMC food machinery corporation
JBT John Bean technologies
MICs minimum inhibitory concentration
P. aeruginosa Pseudomonas aeruginosa
PUFA polyunsaturated fatty acid
S. Typhi Salmonella Typhi
SPME-GC/MS solid-phase microextraction gas chromatography–mass spectrometry
tr trans
USDA the United States department of agriculture
1 Introduction
Varieties of citrus species are widely grown and cultivated in both tropical and subtropical regions of the world. The citrus
genus originated in India more than 30 million years ago and is distributed throughout the world (Matheyambath,
Padmanabhan, & Paliyath, 2016;Nayak et al., 2015;Sawamura, 2010). The most popular members of the citrus belonging
to the Rutaceae family and Aurantioideae subfamily are sweet orange (Citrus sinensis), sour orange (Citrus aurantium),
lemon (Citrus limon), key lime (Citrus aurantifolia), grapefruit (Citrus paradisi), mandarin (Citrus reticulata), and ber-
gamot (Citrus bergawia)(Anwar et al., 2008;Calabrase, 2003).
According to data from 2016, nearly 675 million metric tons of fruit are cultivated worldwide every year. Based on
the production quantities (million metric tonnes), watermelons (117), bananas (113), and apples (89) are located in the
first three ranks, followed by grapes (77) and oranges (73) (FAO, 2019). Citrus varieties are among the favorite types
of fruits produced and consumed extensively. In the FAO’s forecast for 2017, citrus production around the world rose
to 146.5 million tonnes, a 0.7% increment compared to the previous year’s records (145.5 million tonnes to 2016)
(FAO, 2019).
The orange is one of the top-rated citrus fruits, and orange production accounts for more than 50% of global citrus
production. World production of oranges was forecast at 73 million metric tons for 2017/18. Fresh orange consumption
is 29.5million metrics tonnes, while orange account using by industrial processing are 17.7 million metrics tons
(USDA, 2018). Orange production (in thousand metric tonnes) in the main producing countries from the 2013/14 season
to the 2017/18 one is shown in Table 1 (USDA, 2018).
The cold pressing technique is a unique process applied to the extraction of edible oils from various oily seeds, kernels,
peels, and fruits, etc. This technique plays an important role in producing specialty oils with typical characteristic aroma
compounds and functional and nutritional compositions. Moreover, cold pressed oils are accepted as rich in polyunsatu-
rated fatty acids (PUFAs) and preferred for their desirable flavor characteristics, with bioactive components having ther-
apeutic effects (Aydeniz, G€
unes¸er, & Yılmaz, 2014;Yilmaz, Aydeniz, G€
unes¸er, & Arsunar, 2015).
The cold pressing technique has important advantages compared to other extraction techniques, such as lower energy
cost, no needed solvent, and advanced equipment. Cold pressed oils do not contain any chemical contaminants or additives
and require physical or chemical refining processes. Lower oil yield compared to solvent extraction is considered the most
Cold Pressed Oils. https://doi.org/10.1016/B978-0-12-818188-1.00012-8
Copyright ©2020 Elsevier Inc. All rights reserved. 129

TABLE 1 World orange production.
Years (1000 metric tonnes)
Production 2013/14 2014/15 2015/16 2016/17 2017/18 2018/19 (Feb)
Brazil 17.870 16.714 14.414 20.890 15.708 17.750
China 7.600 6.600 6.900 7.000 7.300 7.200
European Union 6.550 5.954 6.038 6.739 6.269 6.512
United States 6.140 5.763 5.523 4.616 3.555 5.022
Mexico 4.533 4.515 4.603 4.630 4.530 4.630
Egypt 2.570 2.635 2.930 3.000 3.120 3.420
Turkey 1.700 1.650 1.800 1.850 1.905 1.885
South Africa 1.723 1.645 1.275 1.363 1.550 1.620
Morocco 1.001 868 925 1.037 1.021 1.200
Vietnam 590 566 637 768 770 770
Argentina 800 800 800 700 600 500
Australia 430 430 455 480 515 500
Costa Rica 315 220 335 322 315 310
Guatemala 154 161 177 179 180 180
Israel 69 86 86 81 76 90
Other 209 166 179 183 182 183
Total 52.254 48.773 47.077 53.838 47.596 51.772
Fresh dom. consumption
China 6.865 6.043 6.446 6.717 7.058 6.950
European Union 5.549 5.333 5.407 5.950 5.735 5.874
Brazil 6.036 5.196 4.940 4.761 4.933 4.976
Mexico 3.312 2.947 2.929 2.473 2.573 2.470
Egypt 1.385 1.350 1.380 1.380 1.480 1.690
Turkey 1.284 1.310 1.366 1.402 1.386 1.400
United States 1.357 1.263 1.346 1.184 1.253 1.277
Morocco 820 688 811 822 826 950
Vietnam 661 602 695 811 832 835
Russia 467 438 470 425 458 475
Saudi Arabia 274 384 371 357 362 370
Iraq 305 247 262 258 335 345
Australia 206 175 235 250 245 245
Bangladesh 113 118 176 169 221 241
Argentina 524 450 469 350 280 230
Other 1.708 1.650 1.757 1.643 1.634 1.674
Total 30.866 28.194 29.060 28.952 29.611 30.002
130 Cold pressed oils

significant disadvantage of the cold pressing technique. Studies reported that some pretreatments such as heating, roasting,
steaming microwave irradiation, and enzyme addition applied on oily material could enhance the oil yield (Aydeniz et al.,
2014;D€
undar Emir, Aydeniz, & Yılmaz, 2015;Khoddami, Man, & Roberts, 2014).
When both desired aroma compounds and a unique composition were considered together, it can be seen that cold
pressed oils have a wide range of applications as a flavor or basic natural perfume agent in cosmetic, pharmacology, aro-
matherapy, personal care, manufacturing, and the food industry (Aydeniz-G€
unes¸er & Yilmaz, 2017;Malacrida, Kimura, &
Jorge, 2012;Matthaus &
€
Ozcan, 2012).
Cold pressed orange oil is added at a 0.01% level (v/v) to juices and concentrated juices in order to give a desirable
unique flavor and aroma. Beverages and bakery and confectionery products such as cookies, chocolate, caramels, licorice,
jelly, and chewing gum containing cold pressed orange oil as a flavoring agent are popular with many consumers
(Braddock, 1999;Ringblom, 2004).
Recently, the cold pressing technique is located between the eco-friendly techniques to extraction oil from food waste
and by-products (Aydeniz et al., 2014;Aydeniz-G€
unes¸er & Yilmaz, 2017). Citrus seeds are accepted as valuable and cheap
oil sources rich in omega and PUFAs, and phenolics such as naringin and hesperidin which have antiinflammatory and
antihypertensive effects (Benavente-Garcı
´a & Castillo, 2008;Manners, 2007).
This chapter focuses on orange seed and peel oils obtained from the cold pressing technique and reviews the compo-
sitional properties, aromatic and sensory profile, major and minor bioactive compounds, health-promoting traits, and food
and industrial applications of cold pressed orange oils.
2 Some physicochemical properties of cold pressed orange oils
Citrus seeds and citrus peel are preferred in the obtaining of aromatic essential oils. High oil contents of popular citrus types
play an important role in consumer preference. Various factors such as geographical origin, soil type, climatic conditions,
and harvest time can cause changes in the oil content of citrus seeds. The oil contents of lemon (Citrus lemon), orange
(Citrus sinensis), and grapefruit (Citrus paradisi) seeds were determined as 34%–45%, 27%–52%, and 36%–49%, respec-
tively, by the solvent extraction technique (Anwar et al., 2008;Saidani, Dhifi, & Marzouk, 2004). Furthermore, different
studies exist in the literature indicating oranges’ oil content, oil characteristics, and seed properties (Malacrida et al., 2012;
Matthaus &
€
Ozcan, 2012;Saidani et al., 2004). Saidani et al. (2004) indicated that sweet oranges (51.8%) have a higher oil
TABLE 1 World orange production—cont’d
Years (1000 metric tonnes)
Production 2013/14 2014/15 2015/16 2016/17 2017/18 2018/19 (Feb)
For processing
Brazil 11.832 11.506 9.466 16.116 10.771 12.770
United States 4.420 4.133 3.684 3.001 2.014 3.350
Mexico 1.200 1.550 1.650 2.100 1.900 2.100
European Union 1.474 1.251 1.286 1.491 1.253 1.363
China 715 650 600 580 570 590
Costa Rica 208 125 230 238 232 227
Argentina 200 278 270 273 257 223
South Africa 471 403 142 123 201 220
Egypt 85 85 100 100 100 130
Turkey 100 80 100 100 98 95
Other 200 200 129 141 141 160
Total 20.905 20.261 17.657 24.263 17.537 21.228
Adapted from USDA (2019).
Cold pressed orange (Citrus sinensis) oil Chapter 12 131

content than bitter oranges (34%). In another study, the oil contents in bitter and sour orange seeds determined by a
Twisselmann-type extractor were 56.5% and 57.4%, respectively (Matthaus &
€
Ozcan, 2012). Table 2 shows the physico-
chemical properties of seed oils obtained as a by-product during grapefruit and orange processing.
Similarly, fatty acid and tocopherol compositions having impact on oils characterization were reported by several
researchers (Table 3). The major fatty acids were oleic, linoleic, and palmitic acids in Citrus sinensis (bitter) and Citrus
sinensis (sour) seed oils according to Matthaus and
€
Ozcan (2012). Same researchers also reported 178 and 175 ppm as total
TABLE 2 Some physicochemical properties of grapefruit and orange
seeds and seed oils (El-Adawy, El-Bedawy, Rahma, & Gafar, 1999;Habib,
Hammam, Sakr, & Ashoush, 1986;Malacrida et al., 2012).
Property Orange seed
Oil yield (%) 51.80–41.50
Protein content (%, N*6.25) 17.40
Dietary fiber content (%) 22.53
Ash content (%) 2.95–3.17
Orange seed oils
Refractive Index (25°C) 1.4681
Specific gravity (g/ml) (25°C) 0.914–0.933
Acid value (mg KOH/g oil) 0.21–0.673
Iodine number (g I/100g oil) 99.2–102.57
Peroxide value (meq O
2
/kg oil) 6.37
Saponification number (mg KOH/g oil) 190.2–196.8
TABLE 3 Fatty acid and tocopherol compositions of citrus seed oils (Anwar et al., 2008;
Malacrida et al., 2012;Saidani et al., 2004).
Fatty acid (%) Grapefruit seed oils Lemon seed oils Orange seed oils
C16:0 32.17 17.17–21.03 24.73–26.42
C16:1 0.20 0.65 0.40
C18:0 3.64 2.30–3.67 3.40–5.27
C18:1 21.93 20.80–26.20 14.90–26.00
C18:2 36.10 24.70–44.31 38.44–40.30
C18:3 4.36 6.90–8.96 3.92–4.58
C20:0 0.29 0.31 0.38
Totally saturated 36.10 25.28 30.98–32.45
Totally unsaturated 64.10 74.72 59.85–69.02
Totally essential fatty acids 40.46 43.02
Tocopherol (mg/kg oil)
a-tocopherol 380 102.49 300.19
g-tocopherol 43.41 1.33 Not detected
d-tocopherol 9.08 18.98 18.60
132 Cold pressed oils

tocopherol contents (the majority consists of a-tocopherol), and 2038 and 2506 ppm as total sterols (the majority consists of
b-sitosterol) in bitter and sour orange seed oils, respectively. Most of the reported values in Tables 2 and 3 are recognized as
extracted seed oils by laboratory-scale solvent extraction. Citrus oil production by cold pressing is attracting increasing
attention for people who do not prefer refined foods and recent studies have focused on the cold pressed technique.
In another study, Aydeniz-G€
unes¸er and Yilmaz (2017) evaluated the effects of microwave and conventional-heat
treatment on all quality parameters of orange seed oils produced via cold pressing (Table 4). It is apparent that microwave
treatment on orange seeds before cold pressing could enhance oil yield to 63% by 15.8% increments. Turbidity measure-
ments and a*values indicating red-green colors in the control group (conventional heat treatment) were lower than those of
the microwave-treated group.
Although there were no statistically significant differences for acid, peroxide, and iodine values, it was possible to say
that these three values of microwave-treated samples have slightly higher values compared to another group. All orange
seed oils produced by cold pressing could be fairly suitable with upper limits (4.0 mg KOH/g oil acid value, and 15 meq
active O
2
/kg oil peroxide value for cold pressed and virgin oils) appeared in the Codex Standard for Named Vegetable Oils
(Alimentarius, 1999).
Acid and peroxide values were also reported for orange seed oils obtained from solvent extraction. Habib et al. (1986)
determined the free fatty acid values of orange and mandarin seed oils as 0.21 and 0.65 mg KOH/g oil, respectively. Sim-
ilarly, El-Adawy et al. (1999) reported the acid value as 0.67 mg KOH/g oil and peroxide value as 6.37 meq active O
2
/kg oil
for orange seed oil extracted with n-hexane. Saloua, Eddine, and Hedi (2009) observed the 2.33 meq active O
2
/kg oil per-
oxide value and 1.86 p-anisidine value in orange seed oils.
Press meal, in other words the oily cake, is another important by-product obtained during the cold pressing technique,
and it has been used in possible purposes due to its contained proteins, oil, and dietary fiber. Aydeniz-G€
unes¸er and
TABLE 4 The physicochemical properties of orange seed oils obtained by cold pressing
(Aydeniz-G€
unes¸er & Yilmaz, 2017).
Property Cold pressed Microwave+ cold pressed
Oil yield
a
(%) 52.930.38
B
62.992.36
A
Specific gravity (g/mL (25°C) 0.920.01
A
0.920.01
A
Refractive Index (25°C) 1.470.01
A
1.470.01
A
Viscosity (25°C, cP) 59.550.52
A
59.750.15
A
Turbidity (NTU) 13.504.05
B
34.258.67
A
Color L 33.593.22
A
31.672.19
A
a*0.390.18
B
1.770.189
A
b*15.696.20
A
15.053.85
A
Sediment content (%) 6.650.97
A
7.572.82
A
Free fatty acid (%, linoleic acid) 0.270.01
B
0.340.04
A
Acid value (mg KOH/g oil) 0.540.01
A
0.690.08
A
Peroxide value (meq O
2
/kg oil) 13.193.23
A
15.491.02
A
p-anisidine value 0.870.19
A
0.340.04
B
Iodine number (g I/100g oil) 117.950.89
A
119.334.03
A
Saponification number (mg KOH/g oil) 204.082.11
A
201.060.82
A
Unsaponifiable matter (%) 0.70 0.15
A
0.950.01
A
Total phenolics (mg GA/100g) 4.071179
A
5.607291
A
TEAC (mmol Trolox/100g oil) 12.4311164
B
16.5121168
A
A-B
means in the same rows followed by different superscript letters were significantly different (P<.05).
a
Oil yield values are calculated over the total oil content of the orange seeds.
Cold pressed orange (Citrus sinensis) oil Chapter 12 133

Yilmaz (2017) analyzed the pressed meals exiting after cold pressing of the orange seeds. Researchers observed that the
oil and water contents in orange seed press meal could remain at up to 11% and 18% after the cold pressing, respectively.
Moreover, press meal was accepted as a rich source of protein (21%–25%) and dietary fiber (82%–84%). Proximate
composition of press meal of microwave roasted seed was statistically different from that of regular roasted seed in terms
of water activity oil, protein, and color a*values (more red). Even though press meal obtained from microwave-roasted
seeds has higher protein and color a*values, the oil and water activity values in this group were lower than those of the
control group (press meal obtained from regular roasted orange seeds). Table 5 sets out the selected properties.
3 Extraction and processing of cold pressed orange oil
Essential oils have been known probably since ancient societies which have fragrance culture. From Mayans and Aztecs to
Arabs, Egyptians, and Romans, essential oils were used for different purposes in perfumery, sacred ceremony, religious
rituals, and also mummification (Chemat & Sawamura, 2010). Various and complex volatile substances have important
effects on the essential oils aromatic composition and their chemical profile. The selection technique of extraction of
essential oils from plant materials is closely related to crucial parameters such as the extraction temperature, extraction
time, solvent type, extraction pressure, and the presence of oxygen (d’Acampora Zellner, Dugo, Dugo, & Mondello, 2015).
Conventional and innovative essential oil extraction techniques having the different working principles were reported
by several researchers (Eikani, Golmohammad, & Rowshanzamir, 2007;Kaufmann & Christen, 2002;Lucchesi, Chemat,
& Smadja, 2004;Vian, Fernandez, Visinoni, & Chemat, 2008). The most popular extraction procedures are as follows:
i. Steam and hydro-distillation (SD)
ii. Solvent extraction (SE)
iii. Supercritical fluid extraction (SFE)
iv. Pressurized-fluid extraction
TABLE 5 Proximate composition of the oily meal released during cold pressing (Aydeniz-G€
unes¸er &
Yilmaz, 2017).
Orange seed meal
Property
Control
orange seed Property Control
Microwave+ cold
pressed
Seed size (mm) Moisture (%) 11.110.09
A
9.721.46
A
Length 11.690.49 Water activity
(25°C)
0.710.01
A
0.650.06
B
Width 5.060.13 Ash (%) 4.190.09
A
4.410.03
A
Height 4.010.12 Oil
a
(%) 17.970.58
A
13.570.74
B
1000-seed weight (g) 197.212.90 Protein
a
(%) 20.680.29
B
25.611.08
A
Skin: flesh ratio 0.29 0.02 Color L 54.140.99
A
51.820.24
A
Color L 49.33 3.17 Color a*6.20 0.47
B
8.600.28
A
a*2.420.45 Color b*22.270.73
A
22.480.46
A
b*17.471.71
Moisture (%) 43.99 0.13
Water activity (25°C) 0.960.01
Oil
†
(%) 40.752.17
Protein
a
(%) 19.220.09
Ash (%) 1.580.01
A-B
means in the same rows followed by different superscript letters were significantly different (P<.05).
a
Values are on dry weight basis.
134 Cold pressed oils

v. Simultaneous distillation-extraction (SDE)
vi. Soxhlet extraction
vii. Solvent-free microwave-assisted hydrodistillation (SFMAHD)
viii. Water-free microwave-assisted hydrodistillation (WFMAHD)
ix. Dynamic headspace techniques (DHS)
x. Static headspace techniques (SHS)
xi. Solvent-assisted flavor evaporation (SAFE)
xii. Ultrasound accelerated solvent extraction
xiii. Solid-phase microextraction (SPME)
xiv. Direct thermal desorption (DTD)
xv. Cold pressing (Baser & Buchbauer, 2015;Chemat & Sawamura, 2010;d’Acampora Zellner et al., 2015)
It was reported that essential oils and aroma compounds that have characteristic and desirable odorants could be extracted
from the different parts such as the flowers, leaves, twigs, peel, seeds, fruit, and pulp of citrus species by the cold pressing
technique (Mukhopadhyay, 2000). Cold pressed essential oils have a yellowish-brown color, a fresh floral odor and are rich
in limonene, b-myrcene, and a-pinene (Anwar, Ahmed, Speciale, Cimino, & Saija, 2015).
Cold pressed citrus oils including lemon, lime, bergamot, mandarin, sweet and bitter orange, and grapefruit oils contain
more than 200 volatile components (mostly terpenes and their oxygenated derivatives, aldehydes, aliphatic and aromatic
hydrocarbons, alcohols, and esters) and nonvolatile components (mainly oxygen heterocyclic compounds such as cou-
marins, psoralens, flavones, fatty acids, sterols, fat-soluble color pigments, and lipid waxes) (d’Acampora Zellner
et al., 2015;Russo et al., 2015).
One of the most popular extraction systems is the JBT (John Bean Technologies) oil recovery system (formerly named
the Food Machinery Corporation or FMC) to obtain cold pressed orange oil effectively. The working principle of the JBT
system (Fig. 1) is based on the pressure and shredding mechanisms, another means of crushing the fruit together with
the fruit peel. Four different products—peel, core, juice, and oil/water emulsion—are obtained at the end of extraction.
Extractor
Cyclone
Finisher
Fresh water
Filter
Rec
y
cle water tank
De-sludger
Polisher
FIG. 1 Typical JBT oil recovery system.
Cold pressed orange (Citrus sinensis) oil Chapter 12 135

The obtained juicy part (oil-in-water emulsion) contains not only fruit juice but also oil glands in peel. The oily phase was
separated from the emulsion medium with the aid of a centrifugation process, then cold pressed orange oil was recovered
(Di Giacomo & Di Giacomo, 2003;Ringblom, 2004). The JBT process has important advantages such as lower energy
requirement and being able to extract the fruit juice and peel oil simultaneously ( JBT, 2018).
Oil yield may vary significantly according to varieties of the fruit, harvest time, soil-climate interactions, ripening
degree, extraction procedure applied to oily material conditions, and citrus types. The different citrus peel oils yield were
determined as 0.2%–0.4% for grapefruit peel oil, 0.35%–0.5% for lime peel oil, and 0.5%–1.15% for lemon peel oil.
Moreover, 3–7.5 g essential oil could be extracted from 1 kg of orange peel (0.3%–0.75% yield) (Kesterson &
Braddock, 1975).
Another one of the most widely used machines is the Brown Oil Extractor. This system allows oil to be recovered from
citrus peel before the citrus juice extraction. In the first step in this extraction unit, citrus fruits are exposed to pairs of
rotating rollers with sharp needles, and the oil in the citrus peel is washed with water to remove it as an emulsion. The
emulsion containing peel oil is obtained from a centrifugation process applied in the final stage. Although the Brown
Oil Extractor and JBT systems have similar technical points, the peel oils recovered from both systems may exhibit dif-
ferent characteristics. The Brown Oil Extractor achieved the maximum oil yield and has a greater fruit processing capacity
per unit time than the JBT system (Kesterson, Braddock, & Crandall, 1979;Somogyi, Barrett, & Hui, 1996).
3.1 Quality control of cold pressed orange oils
Cold pressed oils have contanied various impurities including phospholipids, pigments, free fatty acids, gummies, and
waxes. because of unrefined oils that could exhibit sensitivity to heat, oxygen, and light. All of these factors that cause
degradation of the oil quality play a role in consumer preferences and purchasing intentions for cold pressed oils. Unlike
refined vegetable oils, cold pressed oils should be stored in dark glass bottles sealed tightly away from oxygen and sunlight
(JBT, 2018). Another important point on cold pressed orange oils is to avoid metal contamination. Stainless steel should be
preferred to iron and copper as a packaging material, to inhibit oil degradation and protect flavor components ( JBT, 2018).
4 Fatty acids profile of cold pressed orange oil
It has been noted that different part of citrus varieties could be evaluated as a valuable oil source, containing oil in a wide
range from 27% to 52%. It is important to mention that the fat-soluble compounds such as carotenoids, phenolics, tocoph-
erols, and phytosterols also have important roles in the oil content of the citrus (Anwar et al., 2008;Malacrida et al., 2012).
Jorge, da Silva, and Aranha (2016) confirmed total carotenoid, a-tocopherol, and phytosterol contents as 19, 136, and
1304 mg/kg oil in orange seed oils, respectively. The fatty acid composition also has major importance in determining
oil characterization and oil quality. In a study (Aydeniz-G€
unes¸er & Yilmaz, 2017), fatty acids composition were quantified
in cold pressed orange seed oils and it was observed that 65% of the composition occurred as unsaturated fatty acids, mainly
oleic (25%) and linoleic (37%). A balanced saturated/unsaturated fatty acids ratio, which is used as an indicator of oil nutri-
tional quality, was approximately 0.47 in orange seed oils (Table 6).
TABLE 6 Fatty acid compositions (%) of orange seed oils obtained by cold pressing
(Aydeniz-G€
unes¸er & Yilmaz, 2017).
Cold pressed Microwave+ cold pressed
Fatty acid (%)
Palmitic (C16:0) 25.710.23 26.10 0.08
Palmitoleic (C16:1) 0.52 0.01 0.52 0.01
Stearic (C18:0) 5.750.11 5.870.03
Oleic (C18:1 n-9) 25.330.12 24.81 0.06
Linoleic (C18:2 n-6) 36.590.17 36.61 0.05
Linolenic (C18:3 n-3) 4.140.02 4.19 0.01
136 Cold pressed oils

The fatty acid compositions of the cold pressed orange seed oil are summarized in Table 6. There was no effect of
microwave treatment before cold pressing on the fatty acid composition. It is possible to find different results and discus-
sions about fatty acid compositions in the literature. Saidani et al. (2004) analyzed the major fatty acids in sweet orange seed
oils as 34% palmitic, 15% oleic, and 40% linoleic acid. Likewise, Matthaus and
€
Ozcan (2012) determined major four fatty
acids as palmitic (27%), oleic (22%), linoleic (39%), and linolenic (4%) in orange seed oils grown in Turkey. In another
study, fatty acid composition with a majority of linoleic acid (76%) was quantified in the Osage orange (Maclura pomifera
(Rafin)) (Saloua et al., 2009).
A recent study by Matsuo, Miura, Araki, and Yoshie-Stark (2019) investigated the peel oil characteristics of C. Natsu-
daidai cultivars, a hybrid orange citrus. The results of this study indicated that most (70%) of the fatty acids present com-
prised unsaturated fatty acids such as linoleic acids (19–53 mg/100 g oil). Al Juhaimi et al. (2018) studied the effect of
different drying temperatures (60°C, 70°C, and 80°C) on the antioxidant capacity and fatty acid composition of Kinnow
mandarin, Orlando orange, and Eureka lemon seed oils. Although the quality parameters analyzed in all the citrus seed oils
were significantly affected by drying conditions, the Orlando orange seed had the highest total phenolics content and anti-
oxidant capacity values. In the fatty acid compositions of three citrus seed oils, linoleic and palmitic acids were the most
abundant unsaturated and saturated fatty acids. Researchers observed that the Orlando orange has more palmitic acid (27%)
and stearic acid (4%) than the Kinnow mandarin and Eureka lemon, and also approximately 23% oleic and 39% linoleic
acids, respectively.
5 Minor bioactive compounds profile of cold pressed orange oils
The distilled products of concentrated cold pressed orange essential oil have characteristic organoleptic and volatile aroma
compounds (Licandro & Odio, 2002). Hydrocarbons and alcohols (monoterpenic, sesquiterpenic, and aliphatic), aldehydes
(monoterpenic and aliphatic), ketones (monoterpenic and sesquiterpenic), esters (monoterpenic and aliphatic), and their
oxides are most abundant volatile components in cold pressed and also hydro distilled bitter orange oils (Anwar et al.,
2015). It is accepted that a significant part of cold pressed citrus oils comprise volatile fractions (85%–99%) and also
contain a minor amount of nonvolatile fractions (1%–15%) such as citropten, meranzin, isomeranzin, bergapten, cnicidin,
oxypeucedanin, sinensetin, cnidilin, and phellopterin, classified in coumarins, psoralens, and polymethoxflavones (Anwar
et al., 2015;Russo et al., 2015).
Russo et al. (2015) developed high-resolution HPLC methods to investigate the oxygen heterocyclic compounds in
various cold pressed citrus essential oils. Researchers detected 38 different nonvolatile components in lemon, bergamot,
grapefruit, orange, and mandarin essential oils. Ten compounds (mostly meranzim, isomeranzim as coumarins, and epox-
ybergamottin as polymethoxflavones) and six oxygen heterocyclic compounds (mostly nobiletin heptamethoxyflavone,
and tangeretin as polymethoxflavones) were determined in bitter orange and sweet orange, respectively (Russo et al., 2015).
Physicochemical properties and the fatty acid, sterol, and tocopherol compositions of cold pressed orange seed oil were
characterized by Aydeniz-G€
unes¸er and Yilmaz (2017). In addition, the effects of microwave pretreatment (360 W, total
30 min) and conventional roasting (30 min at 150°C) before cold pressing on all analyzed values were compared. Fifteen
different sterols were quantified in cold pressed orange seed oil. b-sitosterol (78%), campesterol (10%), and stigmasterol
(3%) were determined as the major sterols in composition. When compared to tocopherol contents of both oil samples,
cold pressed orange seed oils have a higher a-tocopherol content (283 ppm) than that (256 ppm) of the microwa ve pretreated
group. It was shown that microwave pretreatment caused significant increases in oil yield, turbidity, total phenolics, and
antioxidant capacities, although it has no statistically distinct differences on the sterol and tocopherol compositions
(Table 7). Researchers claimed the cold pressed orange seed oils could be used in the food and beverage industries and
also in nonfood applications.
In a recent study (Aydeniz-G€
unes¸er & Yilmaz, 2017), the thermal behavior and the oxidative induction time of cold
pressed orange oils were examined by DSC. Cold pressed orange oils exhibited crystallization onset temperatures range
between 1.53°C and 1.90°C, and orange oils started to melt trending at around 25°C. It was noteworthy that microwave
roasting (at 600 w power) of orange seeds prior to cold pressing improved the oxidative stability of orange oil (Table 8), in
addition to having no effect on temperatures and enthalpies of crystallization and melting.
6 Flavor and sensory characterization of cold pressed orange oils
The volatile components are one of the major important factors in determining oil sensory quality. It is thought to be a linear
relationship between the functional properties of thymol, limonene, a-pinene, terpinene, and oil stability and quality.
Monoterpenic-, sesquiterpenic-, and aliphatic aldehydes, ketones, alcohols, esters, and oxides are accepted as the most
popular volatile fractions found in citrus oils. Limonene, a monoterpene, is an aromatic volatile compound obtained from
Cold pressed orange (Citrus sinensis) oil Chapter 12 137

TABLE 7 Sterol and tocopherol compositions (%) of the orange seed oils
produced by cold pressing (Aydeniz-G€
unes¸er & Yilmaz, 2017).
Orange seed oil
Cold pressed Microwave+ cold pressed
Sterol (%)
Cholesterol 0.660.03
A
0.770.06
A
Brassicasterol 0.070.02
B
0.490.32
A
24-Methylen cholesterol 0.05 0.01
B
0.180.07
A
Campesterol 9.430.12
A
9.970.17
A
Campestanol 0.210.04
A
0.260.08
A
Stigmasterol 3.260.15
A
3.470.06
A
Delta-7 campesterol 0.290.02
B
0.650.02
A
Delta-5,23 stigmastadienol nd 0.190.07
Chlerosterol 1.160.05
A
0.830.15
B
Beta-sitosterol 78.720.91
A
77.651.49
A
Sitostanol 0.620.10
B
2.320.99
A
Delta-5 avenasterol 4.590.05
A
1.520.93
B
Delta-5,24 stigmastadienol 0.170.06
B
0.740.37
A
Delta-7 stigmastenol 0.51 0.11
B
0.770.23
A
Delta-7 avenasterol 0.260.12
A
0.180.07
B
Tocopherol (mg/kg oil)
a-tocopherol 283.4024.60
A
256.658.21
A
A-B means in the same rows followed by different superscript letters were significantly different (P<.05).
nd: not detected.
TABLE 8 Thermal properties of the orange seed oils (Aydeniz-G€
unes¸er &
Yilmaz, 2017).
Cold pressed Microwave + cold pressed
Crystallization
Onset
c
(°C) 1.900.36 1.530.14
T
c
(°C) 5.120.18 4.630.53
DH
c
(J/g) 30.560.54 31.202.73
Melting
Onset
m
(°C) 25.790.28 26.160.08
T
m1
(°C) 23.040.41 23.780.18
T
m2
(°C) 2.350.06 2.360.17
T
m3
(°C) 0.630.04 0.470.03
T
m4
(°C) 5.970.31 6.420.28
DH
m
(J/g) 56.812.45 59.416.05
OIT (min) 29.515.08 44.28 6.94

the rind of orange by cold pressing and has a critical role in the characteristic citrus smell (Anwar et al., 2015). It was
reported that D-limonene can be obtained as a distilled by-product in the course of vacuum distillation of cold pressed
orange essential oil (Licandro & Odio, 2002).
Aydeniz-G€
unes¸er and Yilmaz (2019) investigated bioactive and volatile aromatic compounds of orange seed oil
obtained by the cold pressing technique under mild operation conditions. According to the SPME-GC/MS method, 33 dif-
ferent volatiles were quantified in cold pressed oils obtained from oven preroasted and microwave preroasted orange seeds.
The volatile composition comprise mainly monoterpene hydrocarbons and monoterpene alcohols, wherein D-limonene has
the highest content (4500–5900 mg/kg oil) in all cold pressed oil samples followed by b-myrcene (87–124 mg/kg oil),
a-terpineol (44–49 mg/kg oil), and b-pinene (31–47 mg/kg oil), respectively (Table 9).
The volatile profile of treated orange seeds with the microwave under 60 w power before cold pressing contained the
main pyrazines including methyl pyrazine, 2,5-dimethlypyrazine, 3-methoxy-1-butanol, and octanal. Microwave treatment
led to an increase in green, sweet, bitter almond, burnt, and roasted aroma levels and a decrease in creamy, woody, spicy,
fresh citrus, and floral aroma levels compared to cold pressed oils obtained from nontreatment seeds. Similarly, Moufida
and Marzouk (2003) observed that D-limonene levels changed from 63% to 90% in various orange species such as blood,
sweet, and bitter orange wherein D-limonene was detected as a principal aromatic compound.
7 Health-promoting traits of cold pressed orange oil and oil constituents
Citrus species contain various bioactive compounds that provide demonstrated pharmacological and physiological benefits,
and protective and reducing effects against chronic and degenerative diseases. In recent years, plant-originated phenolic
compounds have drawn much attention as not only nutraceuticals but also potential cancer-preventing agents.
Minor bioactive lipids (sterols, tocopherols, carotenoids, hydrocarbons, and flavor and aroma compounds) in citrus
provide important contributions via their health-promoting effects such as antioxidant, antimicrobial, antimutagenic, antic-
holesterol, antidiabetes, antiinflammatory, and antihypertensive activities (Aydeniz et al., 2014;Choi, Sawamura, & Song,
2010;Luther et al., 2007). Moreover, different parts of citrus such as lemon, orange, and mandarin are accepted as rich
sources of flavonoids including naringin, hesperidin, and limonoid glucosides such as limonin, nomilin, and obacunone
which have a free radical scavenger effect, antihypertensive effect, and inhibitory effect of stomach and lung carcino-
genesis (Benavente-Garcı
´a & Castillo, 2008;Lam, Zhang, & Hasegawa, 1994;Manners, 2007;Miller et al., 1994). Both
functional and clinical properties of essential oils rich in biologically active compounds were confirmed by several
researchers in the literature.
In a recent study (Aydeniz-G€
unes¸er & Yilmaz, 2019), the phenolic composition of cold pressed orange oils was deter-
mined and it was showed that the majority of phenolic composition (78%) occurred from flavonoids such as naringin and
hesperidin (Table 10). In addition to flavonoids, phenolic acids, especially tr-ferulic acid (222 ppm), were also detected.
Before the cold pressing process, microwave treatment at 360 w for a total of 30min has a positive effect on the orange seeds
and improved the flavonoid contents such as eriocitrin, rutin, naringin, naringenin, and neohesperidin. Researchers con-
cluded that flavonoids contained in orange seeds could be transferred into the seed oil during cold pressing, and orange oil
consumption provides positive impact on health.
Carotenoids are known as the main color pigments in citrus varieties, and carotenoid derivatives such as b-carotene,
lutein, violaxanthin, anteraxanthin, and cryptoxanthin were commonly detected in orange fruit (Cebadera-Miranda et al.,
2019). Total carotenoid content was determined as 7.7 ppm, and b-carotene and lutein contents were calculated as 7.37 and
7.35 ppm in cold pressed orange oils, respectively (Aydeniz-G€
unes¸er & Yilmaz, 2019).
Aromatherapy, defined as “the art based on the use of essential oils for a medicinal purpose,” has been subdivided into
clinical, home-care, and aesthetic aromatherapies, and used to ease aches, spasms in influenza, asth ma symptoms, and muscle
pains, and reduce psychological symptoms such as stress, anxiety, depression, insomnia, and panic attacks (Kim, Nam, &
Paik, 2005;Kumagai, Sawamura, & Son, 2010;Soden, Vincent, Craske, Lucas, & Ashley, 2004).
Seed and peel essential oils obtained from various citrus types have been used widely as massage oils and spray oils in
aromatherapy and aroma baths as well as cosmetics and medicines (Kumagai et al., 2010).
Characteristic constituents of essential oil have various therapeutical and pharmacological properties. It has been
reported that myrcene and caryophyllene belong to monoterpenes have sedative, analgesic, antibacterial, diuretic,
and immune stimulant effectiveness. Terpineol located in alcohols group exhibited a mental stimulant effect as well
as antivirus and antibacterial activities. Citronellol (CT) and monoterpene alcohol were naturally present in the citrus
essential oil. The oil’s health benefits include antifungal efficacy in vitro and ataraxic, antiinflammatory, anticonvulsant,
antihyperalgesic, and antidiabetic efficacy in vivo (Brito et al., 2015;de Sousa et al., 2006;Imanishi, 2006;Srinivasan &
Muruganathan, 2016).
Cold pressed orange (Citrus sinensis) oil Chapter 12 139

TABLE 9 Volatile aromatics composition of the orange seed oil samples (Aydeniz-G€
unes¸er & Yilmaz, 2019).
No RI
a
Volatile compound Aroma/flavor description
b
Concentration (mg/kg oil)
Cold pressed Microwave+ cold pressed
1–3-Methylbutanal Fruity, sweet nd 39.05 6.97
2 716 Acetoin Creamy, buttery 24.23 0.87 18.11 2.83
3 799 Hexanal Green, grass 8.90 0.03 16.30 0.95
4 813 Furfural Sweet, caramel, baked bread 24.075.97 45.36 2.10
5 825 Methyl pyrazine Nutty, roasted cacao nd 20
6–2-Furan menthol Roasted cacao, burnt 4.07 0.77 7.960.33
7 877 Isoamyl acetate Banana, fruity 2.80 0.15 2.520.53
8 891 Butrylactone Creamy, fatty, caramel 0.38 0.28 nd
9 911 2,5-Dimethlypyrazine Nutty, roasted nd 4.140.25
10 914 Butyl isobutyrate Pear, pineapple 0.89 0.27 nd
11 924 a-Thujene Woody, green herb 2.86 0.26 2.380.01
12 930 a-Pinene Herbal, turpentine, woody 24.96 0.22 17.68 1.31
13 942 Isopropyl pentanoate Fruity, pear 11.52 0.08 11.59 0.15
14 954 Benzaldehyde Bitter almond 5.241.12 6.50 0.13
15 972 b-Pinene Woody, green pine 47.592.58 31.34 0.72
16 991 b-Myrecene Spicy, terpenic, herbal 124.8913.55 87.33 6.50
17 1000 a-Phellandrene Terpenic, citrus 3.99 0.22 3.57 0.18
18 1004 Octanal Waxy, fatty nd 2.03 0.53
19 1014 3-Carene Sweet 2.890.49 2.33 0.19
20 –3-Methoxy-1-butanol Alcohol nd 2.70 0.47
21 1015 Hexyl acetate Fruity, green apple 4.15 0.63 6.51 4.27
22 1021 b-Cymene Terpenic 22.271.21 14.38 0.73
23 1027 D-Limonene Fresh citrus 5902.07 308.59 4568.84287.69
24 1052 a-Ocimene Fruity, floral 1.70 0.07 1.190.04
25 1058 g-Terpinene Terpenic 32.111.02 27.97 1.97
26 –1-Octenol Green herb, fatty, herbal 1.04 0.18 0.55 0.13
27 1088 (Z)-Linalooloxide Earthy, floral 1.882.67 nd
28 1089 a-Terpinolene Herbal, woody, citrus 12.192.51 10.14 0.08
29 1107 Phenylethyl alcohol Floral, sweet, rose 0.52 0.38 nd
30 1139 (E)-Limonene oxide Citrus 0.930.16 1.32 0.27
31 1179 4-Carvomenthol Woody, spicy 0.85 0.17 0.77 0.01
32 1190 a-Terpineol Floral, lilac 49.32 8.79 44.170.24
33 –Decyl acetate Waxy, fatty, creamy 0.870.29 0.70 0.02
a
RI (Kovat Index) on HP 5 MS column. nd, not detected.
b
Aromatic definitions of the volatile compounds are found from the web pages of http://www.thegoodscentscompany.com/index.html#, http://www.flavornet.
org/flavornet.html.
140 Cold pressed oils

D-limonene is the main terpene and characteristic aromatic component found in the orange peel oils. Clinical studies
related to D-limonene have shown that its benefits include antitumor, hepatoprotective, and chemopreventive effects in
hepatocellular carcinoma and skin cancer (Giri, Parija, & Das, 1999;Imanishi, 2006;Stratton, Dorr, & Alberts, 2000).
Additionally, therapeutic applications of aromatic essential oils can be found in different studies in the literature. Orange
essential oils are accepted as very suitable in therapies for anxiety and nausea. Lehrner, Marwinski, Lehr, Johren, and
Deecke (2005) assessed the impact of orange and lavender essential oils inhalation on patients’ emotional moods in dental
clinics. Researchers showed that the ambient odor of diffused orange oil has a distinct effect in reducing anxiety as well as
increasing positive mood and calmness during the waiting time in dental clinics. Similar results were demonstrated for
pediatric patients (aged 6–9 years), as reported by Jafarzadeh, Arman, and Pour (2013). In this study, orange essential oils
were diffused in a dental operating room air (approximately 10 m
2
) with the aid of an aroma diffuser for 2 min each 10 min.
Following inhalation, it was observed to decrease anxiety symptoms as indicated by the salivary cortisol levels and pulse
rates measured in the children.
Goes, Antunes, Alves, and Teixeira-Silva (2012) evaluated the effectivity of sweet orange essential oil (with the aid of
inhalation in a surgical mask for 5 min) on male patients having anxiety symptoms. Sweet orange essential oil exhibited
potential anxiolytic activity in humans. Extracted oils from fruit peel or flowers of Citrus aurantium (orange bigarade),
Citrus sinensis (sweet orange), and Citrus paradisi (grapefruit) are found to be beneficial to alternative and complementary
therapies in ailments such as agitation, fatigue, challenging behaviors, stress, and insomnia.
Several studies have considered that cold pressed oils rich in bioactive molecules can pose some antibacterial, antifungal,
and antimutagenic activities. Crowell (1997) and Choi et al. (2010) investigated the antibacterial and antifungal activities of
essential oils and identified that these activities were exhibited not only in the food matrix but also in the human metabolism.
TABLE 10 Flavonoid, phenolic acid and pigment composition of orange seed oils
(Aydeniz-G€
unes¸er & Yilmaz, 2019).
Cold pressed Microwave+ cold pressed
Flavonoids (mg/kg)
Catechin 14.871.22
A
15.250.35
A
Eriocitrin 31.011.22
B
85.783.80
A
Rutin 52.590.39
B
76.480.29
A
Naringin 234.280.56
A
299.8027.20
A
Naringenin 10.380.15
A
13.231.66
A
Hesperidin 909.675.63
A
903.4036.20
A
Neohesperidin 100.990.81
A
125.9019.20
A
Kaempherol 8.640.06
A
9.560.83
A
Phenolic acids (mg/kg)
Gallic acid 42.433.57
A
29.413.40
A
Syringic acid 6.93 0.01
B
7.130.01
A
tr-Ferulic acid 222.972.76
B
364.3055.10
A
Rosmaniric acid 58.080.48
A
77.9014.40
A
tr-2-Hydrocinnamic acid 41.65 0.40
A
47.225.41
A
Pigments (mg/kg oil)
Total carotenoid content 7.64 0.48
A
5.490.14
B
b-Carotene content 7.370.46
A
5.300.14
B
Lutein content 7.350.46
A
5.290.14
B
Total chlorophyll (pheophytin a) 0.200.02
B
0.340.05
A
All values are average of three determinations standard error.
A-B
Different lower case letters within the same row are significantly different (P.05).
Cold pressed orange (Citrus sinensis) oil Chapter 12 141

Muthaiyan et al. (2012) reported the inhibitory effect of cold pressed orange oils against Staphylococcus aureus strains
by means of oil-induced cell lysis and gene expression in the cell wall. In different studies (Nannapaneni et al., 2008, 2009;
O’Bryan, Crandall, Chalova, & Ricke, 2008), cold pressed oils obtained from the Valencia orange inhibit the growth of
pathogenic bacteria such as Salmonella spp., Escherichia coli O157: H7, Campylobacter jejuni,Campylobacter coli,Cam-
pylobacter lari,Arcobacter butzleri, and Arcobacter cryaerophilus.Van Hung, Chi, and Phi (2013) evaluated the anti-
fungal activity of cold pressed oils produced by citrus varieties grown in Vietnam against Mucor,Penicillium, and
Fusarium. The orange essential oils had inhibition percentages of 35%, 36.5%, and 59.5% on the growth of Penicillium
expansum,Mucor hiemalis, and Fusarium proliferatum, respectively.
In another study, Phi, Van Hung, Chi, and Tuan (2015) determined the antimicrobial efficiency of different orange,
lime, and pomelo varieties’ essential oils. Limonene and myrcene-rich orange oils showed a significant inhibitory effect
against B. cereus,S. Typhi, and P. aeruginosa.
Aydeniz-G€
unes¸er, Demirel Zorba, and Yılmaz (2018) investigated the antimicrobial activity of cold pressed orange
seed oils by disc diffusion and MICs methods, and compared their activities with the antibiotic discs. Cold pressed orange
seed oils had inhibition minimum (6.6 mm) and maximum (9.5mm) inhibition zones against Bacillus cereus Holl. No. 8 and
Staphylococcus aureus ATCC 6538P, respectively. Moreover, microwave application on orange seeds before the cold
pressing process had a remarkable impact on Klebsiella pneumonia ATCC 700603 and E. coli ATCC 2592 (10.21 mm
and 11.00 mm inhibition zones, respectively (Table 11). No orange seed oils showed an inhibition effect on yeast species
such as Saccharomyces cerevisiae ATCC 9763 and Candida albicans ATCC 10231. Values recorded from the MICs
TABLE 11 Antimicrobial activity of cold pressed citrus seed oils against bacteria and yeast
species tested by disc diffusion assay (Aydeniz-G€
unes¸er et al., 2018).
Microorganism
Orange seed oil
Cold pressed Microwave + cold pressed
Inhibition zone diameter (mm)
Staphylococcus aureus ATCC 29213 8.00 0.76 9.50 0.76
Staphylococcus aureus ATCC 25923 8.38 1.76 8.75 0.71
Staphylococcus aureus RSKK1009 9.25 1.75 9.250.70
Staphylococcus aureus ATCC 6538P 9.50 0.92 8.75 1.30
Micrococcus luteus ATCC 4698 –
a
–
Bacillus cereus NCIMB 7464 –7.871.46
Bacillus cereus Holl. 6.62 0.52 6.50 0.84
E.coli 0157:H7 ATCC 43895 7.62 0.52 7.12 0.35
Escherichia coli ATCC 25922 8.37 1.30 11.00 2.88
Escherichia coli ATCC 8739 7.12 0.35 7.50 0.76
Salmonella typhimurium ATCC 51812 –7.50 0.53
Salmonella typhimurium ATCC 14028 7.50 0.53 7.50 0.53
Salmonella enteritidis ATCC 13076 7.94 0.68 7.75 1.00
Pseudomonas aeroginosa ATCC 27853 8.00 1.31 9.62 2.85
Klebsiella pneumoniaeATCC700603 8.75 1.75 10.12 2.59
Saccharomyces cerevisiae ATCC 9763 ––
Candida albicans ATCC 10231 ––
Candida utilis –9.75 2.26
All values were expressed as the average of four determinations standard deviation.
a
The zone of inhibition was smaller than the standard size (6 mm).
142 Cold pressed oils

method showed that Klebsiella pneumonia ATCC 700603 was inhibited at 16% concentration of cold pressed orange seed
oil (Table 12). The researchers concluded that cold pressed orange seed oils may be used as natural antimicrobial agent in
oily-based formulations.
8 Adulteration and authenticity of cold pressed oil
As mentioned before, oils can be extracted by both steam distillation and cold pressing techniques. A working group on
contaminants by BAH (German Medicines Manufacturers’ Association) reported a remarkable finding on the pesticide
content of citrus essential oils. The researchers claimed that citrus essential oils obtained from cold pressing were more
likely to contain pesticides than the steam-distilled essential oils were. It was observed that high temperatures at steam
distillation could cause the degradation of thermolabile pesticides, although no heat treatment was applied during the cold
pressing process. In the analyzed 600 essential oil samples, pesticide residues were not determined in distilled essential oils,
in contrast to most (more than 50%) of the analyzed cold pressed oils having positive results for pesticide residues (Klier,
Kn€
odler, Peschke, Riegert, & Steinhoff, 2015). Similarly, Saitta, Di Bella, Salvo, Lo Curto, and Dugo (2000) explained the
presence of organochlorines in lemon, orange, mandarin, and bergamot essential oils produced by cold pressing grown
in Italy.
TABLE 12 Antimicrobial activity of cold pressed citrus seed oils against bacteria and yeast species
tested by minimum inhibition concentration (MIC) assay (Aydeniz-G€
unes¸er et al., 2018).
Microorganism
Orange seed oil
Cold pressed Microwave + cold pressed
Concentration (%)
Staphylococcus aureus ATCC 29213 –
a
–
Staphylococcus aureus ATCC 25923 ––
Staphylococcus aureus RSKK1009 ––
Staphylococcus aureus ATCC 6538P ––
Micrococcus luteus ATCC 4698 ––
Bacillus cereus NCIMB 7464 ––
Bacillus cereus Holl. ––
E.coli 0157:H7 ATCC 43895 ––
Escherichia coli ATCC 25922 100 100
Escherichia coli ATCC 8739 ––
Salmonella typhimurium ATCC 51812 ––
Salmonella typhimurium ATCC 14028 ––
Salmonella enteritidis ATCC 13076 100 100
Pseudomonas aeroginosa ATCC 27853 ––
Klebsiella pneumoniae ATCC700603 16 50
Saccharomyces cerevisiae ATCC 9763 ––
Candida albicans ATCC 10231 ––
Candida utilis
All values were expressed as the average of six determinations standard deviation.
a
No inhibition at the maximum concentration (100% oil) used.
Cold pressed orange (Citrus sinensis) oil Chapter 12 143

9 Conclusion
The sweet (Citrus sinensis) and sour orange (Citrus aurantium) are popular and commercial citrus varieties all over the
world, and they account for 50% of global citrus production with 73 million metric tonnes with production quantity in
2017/2018. Cold pressing is the most suitable technique to obtain citrus seeds, peel, and fruit oils rich in aroma, taste,
and natural bioactive components. Cold pressed orange oils are preferred mainly for food applications as well as cosmetic,
pharmaceutical, and aromatherapy because of their flavor and functional properties such as antimicrobial, antioxidant, and
antiinflammatory effects.
Cold pressed orange oil has high unsaturated fatty acid (linoleic and linolenic) levels and a balanced saturated/unsat-
urated fatty acids ratio (0.47); this oil is therefore accepted as a healthy oil source. Moreover, its carotenoid, flavonoid, and
tocopherol contents have critical importance for consumers’ healthy lifestyle. Clinical tests on D-limonene, a major volatile
compound detected in cold pressed orange oils, drew attention due to orange oil’s antitumor, hepatoprotective, and che-
mopreventive activity. This chapter discussed the compositional, characteristics, sensorial properties, bioactive and volatile
compounds, and health-related claims of cold pressed orange oils. In addition, the usage and basic composition of oil-free
meal gained after cold pressing, possible edible applications, and nonedible applications of cold pressed orange oils were
briefly reviewed.
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146 Cold pressed oils

Chapter 13
Cold pressed Fagus sylvatica L. seed oil
Collen Musara and Alfred Maroyi
Medicinal Plants and Economic Development (MPED) Research Centre, Department of Botany, University of Fort Hare, Alice, South Africa
1 Introduction
The beech (Fagus sylvatica L.) is a common forest tree that belongs to the Fagaceae family (W€
uhlisch, 2008) and is con-
sidered as a climax species in most parts of Central and South Europe, including the British Isles and extending to Crimea
(Geßler et al., 2007a, 2007b;Packham, Thomas, Atkinson, & Degen, 2012). F. sylvatica is the scientific name of the
European beech or common beech, which is a strikingly beautiful tree and one of the most essential large deciduous trees
and widespread broadleaved trees native to Europe (Durrant Houston, de Rigo, & Caudullo, 2016). The species is anemoph-
ilous and mostly allogamic (Schaffalitzky de Muckadell, 1955). An interesting fact is that the F. sylvatica tree can survive
for hundreds of years with coppiced stands living for more than 1000 years, hence it can maintain its high growth rate until
late maturity (Durrant Houston et al., 2016). It is a plant whose fruits (beechnuts) have been used since ancient times for the
production of oil, both edible and technical, and this practice in the second half of the 19th century ceased (Siger, Dwiecki,
et al., 2017;Siger, Jo
´zefiak, & Go
´rna
s, 2017). These trees grow up to 30–45 m and yield nuts with a size of 12–18 mm
(Kr€
ussmann, 1977;Prasad & G€
ulz, 1989;Tutin, 1984). The fruits are ellipsoid of 2.5–3.5 cm in length and not considered
edible, albeit they are eaten by monkeys (Packham et al., 2012).
The beech is usually sing le-stemmed with smooth, thin silver-gray bark, often with slight horizontal etchings and a 3 m
trunk diameter, which resembles an elephant’s foot. Its low-slung branches often droop to the ground (Durrant Houston
et al., 2016). It has a terrestrial habitat and in cultivated forest stands, trees are normally harvested at 80–120 years of age
(W€
uhlisch, 2008). The leaves are lime green with silky hairs, alternate, simple, and entire or with a slightly crenate margin,
10 7 cm, 6–7 lateral veins on each side of the leaf, 50–100 mm 63.5 mm round-toothed leaf blade; the leaves have leaf
stalks (Durrant Houston et al., 2016). As they mature, the leaves become darker shiny green and lose their hairs; they are
stalked, with an oval to elliptic shape and a wavy edge, and they are often not abscissed in the autumn and instead remain on
the tree until the spring (marcescence) (Johnson & More, 2006;Mitchell, 1974). The reddish-brown, torpedo-shaped leaf
buds are long and slender, 30 mm 3 mm thick, and they form short stalks, and have a distinctive criss-cross pattern
(Durrant Houston et al., 2016). The beech is wind-pollinated, monoecious, with the tassel-like male catkins hanging from
long stalks at the end of twigs, while female flowers grow in pairs, surrounded by a cup. Hot, sunny, and dry summers are
ideal for abundant flower and seed production. The F. sylvatica male flowers are borne in the small catkins, which are a
hallmark of the Fagales order (beeches, chestnuts, oaks, walnuts, hickories, birches, and hornbeams) while the female
flowers produce beechnuts (Durrant Houston et al., 2016). The bitter edible nuts are sharply tri-angled in prickly four-lobed
seed cases and are an important source of food for several animals; they play a major part in seed dispersal by hiding the
seeds so that they cannot all be retrieved (Packham et al., 2012). Fruiting normally occurs every 5–8 years with small quan-
tities of seeds being produced, but the fruit is dry and does not split open when ripe (Durrant Houston et al., 2016).
An analysis of pollen records indicates that the species has spread across Europe from small scattered populations left
after the last glaciation (Magri, 2008). The distribution of beech in Europe is highly limited by the high summer temper-
atures, drought, and moisture availability probably because it is likely to become less competitive (Fang & Lechowicz,
2006;Hult
en & Fries, 1986;Kramer et al., 2010). The common beech requires a growing season of at least 140 days
(Magri, 2008), and is usually found at altitudes of more than 1000 m (Horgan et al., 2003;Packham et al., 2012). F. sylvatica
is a hardy, most shade-tolerant broadleaved tree species (Praciak et al., 2013). The beech seedlings survive and grow below
the canopy of established trees, hence natural regeneration is possible in silvicultural systems (Durrant Houston et al.,
2016). The predominance of beech means a reduction of light level in the understorey vegetation level, and this will prevent
most woodland plants from growing with only specialist shade-tolerant plants surviving beneath a beech canopy (Durrant
Houston et al., 2016). F. sylvatica requires a wide range of soils with a pH range from 3.5 to 8.5 and a well-drained, fertile
drier soil such as chalk, limestone, and light loams (Augusto, Ranger, Binkley, & Rothe, 2002). It tolerates rigorous winter
Cold Pressed Oils. https://doi.org/10.1016/B978-0-12-818188-1.00013-X
Copyright ©2020 Elsevier Inc. All rights reserved. 147