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CHAPTER 53
c0053 Usage of Date (Phoenix
dactylifera L.) Seeds
in Human Health and
Animal Feed
Mohamed Ali Al-Farsi
1
, Chang Young Lee
2
1
Date Processing Research Laboratory, Ministry of Agriculture, Oman
2
Department of Food Science and Technology, Cornell University, Geneva, New York, USA
CHAPTER OUTLINE
Introduction 447
Botanical Description 447
Historical Cultivation and
Usage 448
Present Day Cultivation and
Usage 448
Applications to Health Promotion
and Disease Prevention 448
Adverse Effects and Reactions
(Allergies and Toxicity) 451
Summary Points 451
References 451
s0010 INTRODUCTION
p0010 Dates from the date palm tree are popular among the population of the Middle Eastern
countries, providing a staple food for millions of people in arid and semi-arid regions of
the world. The world production of dates has increased from about 4.6 million tonnes in 1994
to 7.2 million tonnes in 2009 (FAO, 2010). Date seeds, also called stones or pits, form part
of the integral date fruit, which is composed of a fleshy pericarp and seed that constitutes
between 10% and 15% of the date fruit’s weight, depending on the variety and quality
(Hussein et al., 1998); thus, approximately 825,000 tons of date seeds are produced annually
(FAO, 2009). As it is also known that date seeds contain valuable bioactive compounds,
utilization of this by-product is highly desirable for the date industry.
s0015 BOTANICAL DESCRIPTION
p0015 The botanical name of the date palm is Phoenix dactylifera L., and it is an important member
of the family Palmacea. There are over 2000 different date varieties, which vary in shape,
size, and weight. Usually they are oblong in shape, although certain varieties may be
almost round. The length ranges from 1.8 to 11.0 cm, and the width from 0.8 to 3.2cm;
the average weight per fruit is 2e60 g (Zaid, 2002). As with the fruit, the seed characteristics
447
Nuts and seeds in Health and Disease Prevention. DOI: 10.1016/B978-0-12-375688-6.10053-2
Copyright Ó2011 Elsevier Inc. All rights reserved.
10053-PREEDY-9780123756886
also vary greatly according to variety, and environmental and growing conditions. The seed
weight ranges from 0.5 g to 4 g, the length from 1.2 to 3.6 cm, and the width from 0.6 to
1.3 cm. The seed is usually oblong, ventrally grooved, with a small embryo, and with a hard
endosperm made of a cellulose deposit on the inside of the cell walls (Zaid, 2002).
s0020 HISTORICAL CULTIVATION AND USAGE
p0020 Evidence of date palm cultivation goes as far back as 4000 BC in what is now southern Iraq
(Zaid, 2002). The date palm is found in the Near East, North Africa, and the American
continent, where dates are grown commercially in large quantities. Date palm tree are prop-
agated by two techniques: seed and offshoot propagation. Seed propagation is the easiest and
quickest method of propagation, but it is not an accurate propagation technique because no
two seedlings will be alike. Because of its diversity, the seed approach can only be useful for
breeding purposes. Date seeds are therefore discarded, or used as fodder for cattle, sheep,
camels, and poultry. The use of date seed for animal feed in the traditional way is still likely the
most common practice.
s0025 PRESENT DAY CULTIVATION AND USAGE
p0025 The development of a tissue culture technique for the mass propagation of date palm plants
has expanded the date palm industry. Substantial advantages are gained from this technique e
a better production rate, greater strength, freedom from pests and diseases, and wider
availability of valuable varieties. At present, seeds are still used mainly for animal feed. A
coffee-like product is made from date seeds by drying, roasting, and grinding them in a similar
way to coffee beans, to produce caffeine-free coffee. Date seed oil has been used to replace the
portions of other vegetable oils in body creams, shampoos, and shaving soap formulations,
and, in general, the quality of these cosmetic formulations is encouraging (Devshony et al.,
1992).
s0030 APPLICATIONS TO HEALTH PROMOTION AND DISEASE
PREVENTION
p0030 Epidemiological studies have consistently shown that high fruit and vegetable consumption is
associated with a reduced risk of several chronic diseases, such as coronary heart disease,
cardiovascular disease, cancers, atherosclerosis, neurodegenerative diseases (such as Parkinson
and Ahlzeimer), and inflammation, as well as aging. This is attributed to the fact that these
foods may provide an optimal mixture of phytochemicals such as dietary fiber, natural anti-
oxidants such as vitamins C, E, and beta-carotene, and phenolic compounds. Interestingly, the
peel and seed fractions of some fruits possess higher antioxidant activity than the pulp fraction
(Guo et al., 2003). Date seeds appear to fit well into this category.
p0035 The moisture, protein, fat, ash, and carbohydrate contents of different date seed varieties from
several studies are shown in Table 53.1. The reported composition of seeds varied as follows:
3.1e10.3% moisture, 2.3e6.4% protein, 5.0e13.2% fat, 0.9e1.8% ash, and 71.9e87.0%
carbohydrates. Date seeds contain relatively high amounts of protein and fat compared to date
flesh, where the levels were 1.5e3.0% and 0.1e1.4%, respectively (Al-Farsi et al., 2007).
Regarding the mineral content of date seeds, Ali-Mohamed and Khamis (2004) reported on six
varieties: their values were as follows (mg/100 g): 459.8e542.2 potassium, 21.7e26.1 sodium,
6.5e11.3 calcium, 61.3e69.5 magnesium, 2.8e6.0 iron, 1.3e1.7 manganese, 1.0e1.4 zinc,
and 0.4e0.6 copper.
p0040 Date seed protein contains the majority of essential amino acids; glutamic acid was the major
amino acid in Deglet Nour and Allige date seeds, representing 17.8% and 16.8%, respectively
(Bouaziz et al., 2008). Al-Hooti and colleagues (1998) reported the fatty acid profile of five
varieties of date seed; oleic acid was the predominant fatty acid (56.1%), followed by palmitic
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acid (11.9%), linoleic acid (11.6%), lauric acid (8.3%), myristic acid (6.0%), and stearic acid
(2.6%).
p0045 Table 53.2 shows the dietary fiber, phenolic, and antioxidant content of several date seed
varieties. Date seeds are a very rich source of dietary fiber; the level varied between 64.5 and
80.15 g/100 g fresh weight. Insoluble dietary fiber (hemicellulose, cellulose, and lignin) is
considered to be the major constituent of seed fiber (Al-Farsi & Lee, 2008). The high nutri-
tional value of date seeds is based on their dietary fiber content, which makes them suitable for
the preparation of fiber-based foods and dietary supplements. Dietary fiber has important
therapeutic implications for certain conditions, such as diabetes, hyperlipidemia, and obesity,
and may have a protective effect against hypertension, coronary heart disease, high cholesterol,
colorectal and prostate cancers, and intestinal disorders (Tariq et al., 2000).
p0050 Date seeds are also a rich source of phenolics and antioxidants, which ranged from 3102 to
4430 mg gallic acid equivalent/100 g, and 58,000 and 92900 mmol Trolox equivalent/100 g,
respectively (Table 53.2). Al-Farsi and Lee (2008) reported the phenolic acids of date seeds; of
the nine phenolic acids detected, p-hydroxybenzoic (9.89 mg/100 g), protocatechuic
(8.84 mg/100 g), and m-coumaric (8.42 mg/100 g) acids were found to be among the highest.
Since the dietary fiber (5.9e8.7 g/100 g), phenolic (172e246 mg gallic acid equivalent/100 g),
and antioxidant (14,600e16,200 mmol Trolox equivalent/100 g) contents in date flesh are
much lower than in date seeds, date seeds could potentially be utilized as a functional food
ingredient (Al-Farsi et al., 2007). Phenolic compounds of fruit seeds, such as phenolic acids
and flavonoids, have been shown to possess many beneficial effects, including antioxidant,
anticarcinogenic, antimicrobial, antimutagenic, and anti-inflammatory activities, and the
t0010 TABLE 53.1 Date Seed Composition
*
Varieties Moisture % Protein % Fat% Ash % Carbohydrate % References
Mabseeli 3.1 3.9 5.0 1.0 87.0 Al-Farsi et al., 2007
Um-sellah 4.4 5.4 5.9 1.2 83.1 Al-Farsi et al., 2007
Shahal 5.2 2.3 5.1 0.9 86.5 Al-Farsi et al., 2007
Fard 10.3 5.7 9.9 1.4 72.7 Hamada et al., 2002
Khalas 7.1 6.0 13.2 1.8 71.9 Hamada et al., 2002
Lulu 9.9 5.2 10.5 1.0 73.4 Hamada et al., 2002
Deglet noor 9.4 5.0 9.2 1.0 75.4 Besbes et al., 2004
Allig 8.6 4.7 11.6 1.0 74.1 Besbes et al., 2004
Ruzeiz 5.4 6.4 9.7 1.0 77.5 Sawaya et al., 1984
Sifri 4.5 5.9 10.0 1.1 78.5 Sawaya et al., 1984
Average 6.8 5.1 9.0 1.1 78.0
*Data are expressed on wet weight basis.
t0015 TABLE 53.2 Dietary Fiber, Phenolics, and Antioxidants of Date Seeds
*
Varieties Fiber
g/100 g
Phenolics
mg/100 g
Antioxidants
mmol/100 g
References
Mabseeli 79.84 4430 58000 Al-Farsi et al., 2007
Um-sellah 80.15 4293 90300 Al-Farsi et al., 2007
Shahal 77.75 3102 92900 Al-Farsi et al., 2007
Fard 67.8 eeHamada et al., 2002
Khalas 64.5 eeHamada et al., 2002
Lulu 68.8 eeHamada et al., 2002
Average 73.1 3942 80400
*Data are expressed on wet weight basis.
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reduction of cardiovascular disease (Shahidi & Naczk, 2004). Thus, it is important to increase
the antioxidant intake in the human diet, and one way of achieving this is by enriching food
with natural phenolics. As some synthetic antioxidants may exhibit toxicity, have high
manufacturing costs, and have lower efficiency than natural antioxidants (Soong & Barlow,
2004), Al-Farsi and Lee (2008) have developed a technique that enriches the dietary fiber and
phenolic content of date seeds to 93.5 g/100 g and 18.1vg ferulic acid equivalent/100 g,
respectively.
p0055 Date seed oil is edible, but, due to the low extraction rate (w9%), it is not competitive
with other oil crops. The average chemical characteristics of four varieties of date seed oil were:
acid value 1.04, iodine value 49.5, saponification value 221.0, and unsaponifiable matter
0.8%. The major unsaturated fatty acid was oleic acid (42.3%), while the main saturated fatty
acid was lauric (21.8%), followed by linoleic (13.7%), myristic (10.9%), and palmitic (9.6%)
(Devshony et al., 1992). The percentage of un-saturation of Ruzeiz and of Sifri date seed
oils was reported to be 52.49% and 54.52%, respectively, which is considered relatively low.
Date seed oil has lower degree of unsaturation and low content of linoleic acid compared with
the commonly consumed vegetable oils, which has potential for human and animal diets
(Sawaya et al., 1984).
p0060 Seed oils of Deglet Nour and Allig cultivars were compared in terms of phenolic,
tocopherol, and sterol profiles (Besbes et al., 2004). The total phenols ranged from 22.0 to
52.1 mg caffeic acid equivalent/100 g, which is relatively high compared to most edible oils
except for olive oil, which is considered to be a rich source of phenolic compounds in the
Mediterranean diet (Besbes et al., 2004). For example, the total phenolic content in olive oil
has been shown to range from 12.4 to 51.6 mg/100 g (Nissiotis & Tasioula-Margari, 2002).
This may explain the fact that the oxidative stability of date seed oils was higher than that of
most vegetable oils, and comparable to that of olive oil (Besbes et al., 2004). Date seed oil
could be also considered as a potential source of natural phenolic compounds, in addition to
their contribution to resistance to oxidative rancidity and their participation in conferring
a specific flavor to the oil (Caponio et al., 1999). Due to the high oxidative stability of date
seed oil, it will be a good ingredient for cosmetic and pharmaceutical products such as
sun-block creams that provide protection against both UV-A and UV-B, which are responsible
for cellular damage (Besbes et al., 2004). a-Tocopherol was found to be the predominant
tocopherol in date seed oils from Deglet Nour (24.97%) and Allig (38.85%) cultivars. The total
sterol content of Deglet Nour and Allig cultivars was 350 and 300 mg/100 g, respectively; the sterol
marker, b-sitosterol, accounted for 83.31 and 78.66% of the total sterols, respectively (Besbes
et al., 2004).These minor components are not only very important for the functionalproperties of
oils (oxidation resistance, taste, aroma, and color), but could also have many health benefits.
p0065 Several studies have reported the advantages of the incorporation of date seed into animal
diets (Elgasim et al., 1995; Hussein et al., 1998; Ali et al., 1999). Some of these advantages
include increased weight gain, improved feed efficiency, and improved meat palatability.
Adding date seed to the starter and finisher diets improved body weight gain, feed conversion,
and growth performance, comparable to the cornesoybean meal diet of broiler chicks
(Hussein et al., 1998). The results show that date seed can be included at 10% in broiler diets to
support and enhance growth performance (Hussein et al., 1998). Elgasim and colleagues
(1995) found that date seed was effective in increasing body weight gain and the deposition of
back fat in sheep. Ali and colleagues (1999) found that a feeding treatment with normal date
seed (7e14%) significantly increased the testosterone in plasma, and the body weight of rats.
The protein of date seeds has a higher concentration of lysine, which is often the limiting
amino acid in diets based on cereals (Sawaya et al., 1984). Thus date seed can be used to
replace some of the expensive vegetable proteins in livestock or poultry feed.
p0070 However, feed value is not only determined by composition, but also by the accessibility and
digestibility of the components. The hard structure of date seeds is a real obstacle to
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optimizing the feed value, although it is also claimed that seeds are an excellent
source of slow-release energy for camels during long desert journeys. Traditionally, date
seeds were soaked in water before they were fed to ruminants. Date seeds submerged in
water for 72 hours will gain 25% in weight, which may increase to 50% after a week
(Zaid, 2002).
s0035 ADVERSE EFFECTS AND REACTIONS (ALLERGIES AND TOXICITY)
p0075 A few studies have reported allergy or hypersensitivity to date palm fruit and pollen (Waisel
et al., 1994; Kwaasi et al., 1999). The high concentration of selenium detected in some date
varieties, which is related to the selenium content of the soil, also gives some cause for
concern (Al-Farsi et al., 2005). However, no studies are available reporting adverse effects of
date seeds.
s0040 SUMMARY POINTS
lDate seeds comprise up to 15% of the date fruit’s weight.
lDate seeds have been used mainly for animal feed.
lThe seeds contain a higher content of protein and fat compared to date flesh.
lThe high content of dietary fiber and phenolics in date seeds makes them a good ingredient
for functional foods.
lDate seed oil has high oxidation stability due to the high content of phenolics.
lUtilization of seed in animal feed will improve weight gain and feed efficiency.
References
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Al-Farsi, M., & Lee, C. Y. (2008). Optimization of phenolics and dietary fibre extraction from date seeds. Food
Chemistry, 108, 977e985.
Al-Farsi, M., Alasalvar, C., Morris, A., Baron, M., & Shahidi, F. (2005). Compositional and sensory characteristics of
three native sun-dried date (Phoenix dactylifera L.) varieties grown in Oman. Journal of Agricultural and Food
Chemistry, 53, 7586e7591.
Al-Farsi, M., Alasalvar, C., Al-Abid, M., Al-Shoaily, K., Al-Amry, M., & Al-Rawahy, F. (2007). Compositional and
functional characteristics of dates, syrups, and their by-products. Food Chemistry, 104, 943e947.
Al-Hooti, S., Sidhu, J. S., & Qabazard, H. (1998). Chemical composition of seeds date fruit cultivars of United Arab
Emirates. Journal of Food Science and Technology, 35,44e46.
Ali, B. H., Bashir, A. K., & Alhadrami, G. (1999). Reproductive hormonal status of rats treated with date pits. Food
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Besbes, S., Blecker, C., Deroanne, C., Bahloul, N., Lognay, G., Drira, N., et al. (2004). Phenolic, tocopherol and
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