Date seeds: chemical composition and characteristic profiles of the lipid fraction
Introduction
The date (Phoenix dactylifera L.) has been an important crop in arid and semiarid regions of the world. It has always played an important part in the economic and social lives of the people of these regions. The fruit of the date palm is well known as a staple food. It is composed of a fleshy pericarp and seed.
The chemical composition and nutritional value of date flesh have been reported (Al-Hootii et al., 1995, Fayadh and Al-Showiman, 1990, Hussein et al., 1976, Mohamed et al., 1983, Rygg, 1946, Salem and Hegazi, 1971, Vandercook et al., 1977, Youssif et al., 1976). Few works have been published on date palm seeds (Al-Hootii et al., 1995, Al-Showiman, 1990, Devshony et al., 1992, El-Shurafa et al., 1982, Hamada et al., 2002). However, these were focused on their chemical composition only and not their thermal and sensorial properties. Pits of date palm (seed) are a waste product of many industries, after technological transformation of the date fruits (Al-Hooti et al., 1997, Hobani, 1998, Khatchadourian et al., 1983, Youssif et al., 1990, Youssif and Alghamdi, 1999, Youssif et al., 1996) or their biological transformation (Abou Zied et al., 1991, Abou Zied and Baghlef, 1983, Abou Zied and Khoja, 1993, Al-Obaidi and Berry, 1976, Nacib et al., 1997, Nacib et al., 1999).
In some date-processing countries, such as Tunisia, date seeds are discarded or used as fodder for domestic farm animals. In Tunisia, the mean annual yield of date fruits is about 100,000 tons. From this, around 1000 tons of date seeds oils would be extracted. The aim of this study was to evaluate the chemical composition of date seeds from two important cultivars grown in Tunisia and to determine fatty acid profiles, thermal profiles and sensorial profiles of their lipid fraction.
Section snippets
Seed material
Date palm fruits were obtained from the National Institute of Arid Zone (Degach, Tunisia). The seeds of the two cultivars under investigation (Deglet Nour and Allig) were directly isolated from 50 kg of date fruit having the same origin, collected at the “Tamr stage” (full ripeness) and kept at 10 °C for a week. The seeds were soaked in water, washed to get rid of any adhering date flesh, and then air-dried. Their relative percentage weight compared with the weight of the fresh fruits was about
Chemical composition of date seed
Table 1 presents the average compositions of Phoenix dactylifera L. date seed of the two studied cultivars. Date pits from Deglet-Nour and Allig cultivars contained 9.4 and 8.6% moisture, respectively. The ash, protein and fat contents (dry weight basis) in Deglet-Nour and Allig seeds were 1.15 and 1.12%; 5.56 and 5.17% and 10.19 and 12.67%, respectively. Accordingly, total carbohydrate content of date pits ranged from 83.1% for Deglet-Nour to 81.0% for Allig. These results were in general
Conclusion
Considering the protein, fat, mineral and carbohydrate contents of date seed, we can conclude that date pits could be used to meet part of the nutritional requirements of animal feeds. This by-product of date processing industries could be regarded as an excellent source of food ingredients with interesting technological functionality that could also be used in food as an important source of dietary fibre.
This preliminary study shows that date seed oils contain high relative percentages of
Acknowledgements
We thank Mr. Fakhfakh Zouheir responsible for U.S.C.R. Microscopy for observations in S.E.M. and Mr. Hammami Mohamed, responsible for U.S.C.R. spectrometry, for chromatographic analysis.
References (49)
- et al.
Phenolic compounds of virgin olive oilinfluence of paste preparation techniques
Food Chemistry
(1999) - et al.
Preliminary analysis and potential uses of date pits in foods
Food Chemistry
(2002) Rheological behaviour of date–water concentrates
Journal of Food Engineering
(1998)- et al.
Effects of processing factors on qualities of emulsified meatball
Journal of Food Engineering
(1998) - et al.
Comparisons on 11 plant oil fat substitutes for low-fat kung-wans
Journal of Food Engineering
(2002) - et al.
Microscopic and rheological studies of fat crystal networks
Journal of Crystal Growth
(1999) - et al.
Characteristics of raspberry (Rubus idaeus L.) seed oil
Food Chemistry
(2000) - et al.
Cornicabra virgin olive oila study of five crop seasons. Composition, quality and oxidative stability
Food Chemistry
(2001) - et al.
The formation of oxytetracycline in date-coat medium
Bioresource Technology
(1991) - et al.
Utilization of date seeds and cheese whey in production of citric acid by Candida lipolytica
Agricultural Wastes
(1983)