Keywords

Afromomum melegueta, Zingiber officinale, Afromomum melegueta , Xylopic aethiopica, Lipid

Introduction

Vegetables are known to be important sources of protective foods [1]. A vegetable includes leaves, stem, roots, flowers, seeds, fruits, bulbs, tubers and fungi [2, 3]. They have also been reported to be good sources of oil, carbohydrates, minerals as well as vitamins [4]. Edible oils from plant sources are of interest in various food and application industries. They provide characteristic flavours and textures to food as integral diet components [5] and can also serve as a source of oleochemicals [6]. Since antiquity, man has used plants to treat common infectious diseases even long before mankind discovered the existence of microbes; the idea that certain plants had healing potential was well accepted [7]. Peppers (chillies) are widely used in tropical countries as soup thickeners, hotness inducers (pungency), colour and flavour enhancers in foods, thus promoting appetite and aiding consumption. In many tropical countries the basic staple is smooth in texture and bland flavour, a highly-spiced sauce is therefore an essential accompaniment to most meals. They are also used in local and modern pharmaceutical preparations by food industries for the seasoning of processed foods, e.g. biscuits and ginger soft drinks [8, 9], and in the preparation of curry powder, tabasco sauce etc. The four pungent flavoured plant varieties considered in this report are: two cultivars of Aframomum melegueta (big and small alligator peppers), Zingiber officinale (ginger) and Xylopic aethiopica (Ethiopian pepper). Aframomum melegueta is a tropical herbaceous perennial plant of the genus Aframomum belonging to the family Zingiberaceae (Ginger family) of the angiosperms in the kingdom plantae. The main difference between the two cultivars of alligator pepper used is in the size of both the fruit and seeds. Aframomum melegueta is a plant with both medicinal and nutritive values, found commonly in the rain forest of Nigeria. The seeds have pungent peppery taste due to aromatic ketones [10]. It is widely spread across tropical Africa including Nigeria, Liberia, Sierra Leone, Ghana, Cameroon, Cote D ivoire and Togo [11]. According to Oyegade et al. [12], the phytochemicals obtained from the seeds of Aframomum melegueta has been used for years in the treatment of infectious diseases. The grains possess active ingredients that may be exploited for local development of antimicrobials. Even in West Africa, alligator pepper is an expensive spice, so is used sparingly. Often, a single whole pod is pounded in a pestle and mortar before half of it is added (along with black pepper) as a flavouring to West African soups or boiled rice. The spice can also be substituted in any recipe using grains of paradise or black cardamom to provide a hotter and more pungent flavour. When babies are born in Yoruba cultures, they are given a small taste of alligator pepper shortly after birth as part of the routine baby-welcoming process, and it is also used as an ingredient at traditional meet-and-greets. In Igbo land in Nigeria alligator pepper with kola nuts are used in naming ceremonies, as presents to visiting guests and for other social events. Grains of Selim refers to the seeds of a shrubby tree, Xylopia aethiopica, found in Africa. It is also known as Kimba pepper, Afrcan pepper, Moor pepper, Negro pepper, Kani pepper, Kili pepper, Senegal pepper, Ethiopian pepper, Hwentia and Guniea pepper. The seeds have a musky flavour and are used as a pepper substitute. It is sometimes confused with grains of paradise. By far the most common name in Wolof is djar in Senegal, and this is how it is listed on most, if not all, café Touba packages. As a spice the whole fruit is used as a hull of the fruit lends an aromatic note (with the taste being described as an admixture of cubed pepper and nutmeg with overtones of resin) whilst the seeds lend pungency. Typically the dried fruit is lightly crushed before being tied in a bouquet garni and added to West African soups. In Senegal the spice is often sold smoked in markets as Poiv-re de Senegal (the whole green fruit is smoked giving the spice a sticky consistency) and when pounded in a pestle and mortar it makes an excellent fish rub. Ginger consists of the fresh or dried roots of Zingiber officinale. The English botanist William Roscoe (1753-1831) gave the plant the name Zingiber officinale in an 1807 publication. The ginger family is a tropical group especially abundant in Indo-Malaysia, consisting of more than 1200 plant species in 53 general. The genus Zingiber includes about 85 species of aromatic herbs from East Asia and tropical Australia. The name of the genus, Zingiber was derived from a Sanskrit word denoting “horn shaped” in reference to the protrusions on the rhizomes [13, 14]. Ginger belongs to the family Zingiberaceae and it is cultivated commercially in India, China, South East Asia, West Indies, Mexico and other parts of the world. It is consumed as a spice and flavouring agent and is attributed to have many medicinal properties. Ginger has been used as a spice and as natural additives for more than 2000 years [15, 16]. Studies have shown that, the long term dietary intake of ginger has hypoglycaemic and hypolipidaemic effect [17]. Ginger has been identified as an herbal medicinal product with pharmacological effect. Ginger suppresses prostaglanding synthesis through inhibition of cycloxygenase-1 and cycloxygenase-2. In traditional Chinese and Indian medicine, ginger has been used to treat a wide range of ailments including stomach aches, diarrhea, nausea, asthma, respiratory disorders [18]. As these plants spices are used both as a spice and for their medicinal properties, the present study was undertaken to determine the fatty acids, phytosterols and phospholipids contents in a bit to expand its 0nutritional application.

Materials and Methods

Collection and treatment of samples

The four different plant products used as spices: Afromomum melegueta (small and big alligator peppers, OO2 and FK1 respectively), Zingiber officinale (ginger, AT1) and Xylopic aethiopica (Ehiopian pepper, FK3) samples were collected from an Ado- Ekiti market, Ekiti State, Nigeria. They were carefully sorted, washed to remove earthen materials and air-dried, after which the dried samples were ground into fine powder using pestle and mortar and stored in screw capped plastic containers prior to analysis.

Extraction of lipid

Each sample (0.25 g) was weighed into the extraction thimble. A volume of 200 ml of petroleum ether (40-60oC boiling range) was measured and added to the dried 250 ml capacity flask. The covered porous thimble with the sample was placed in the condenser of the Soxhlet extractor arrangement that has been assembled [19]. The lipid was extracted for 5 h. The extraction flask was removed from the heating mantle arrangement when it was almost free of petroleum ether. The extraction flask with the crude oil was oven dried at 105oC for the period of 1 h. The flask containing the dried oil was cooled in the desiccator and the weight of the cooled flask with the dried oil was taken.

Preparation of methyl esters and analysis

The extracted fat (50 mg) was saponified for 5 min at 95 oC with 3.4 ml of 0.5 M KOH in dry methanol. The mixture was neutralized by 0.7 M HCl. A volume of 3 ml of 14 % boron trifluoride (BF3) in methanol (Supelco Inc., Bellefonte, PA, USA) was added [19]. The mixture was heated for 5 min at 90oC to achieve complete methylation. All the fatty acid methyl esters (FAME) were extracted into redistilled n-hexane (2×3 ml). The content was concentrated to 1 ml for analysis and 1µl was injected into the injection port of the GC. The FAME was analyzed using these GC conditions: (GC; HP 5890 Series II, autosampler 7673, powered with HP 3365 ChemStation rev. A09.01 [1206] software; Hewlett-Packard Co., Avondale, PA, USA) fitted with a flame ionization detector. Injection type was split injection, split ratio was 20:1 and carrier gas was nitrogen. The inlet temperature was 250oC, column type was HP INNOWAX) capillary column (30 m, 0.25 mm i.d., 0.25 µm film thickness) (Supelco, Inc. Bellefonte, PA, USA). The oven programme was: initial temperature at 60oC, first ramping at 10oC/min for 20 min (260oC), maintained for 4 min; second ramping at 15 oC/min for 4 min (320 oC), maintained for 10 min. Flame ionization detector (FID) was used and the detector temperature was 320 oC. Hydrogen pressure was 22 psi and compressed air was 35 psi. The peaks were identified by comparison of their retention times with authentic standards of FAME.

Sterol analysis

For the analysis of sterols, the gas chromatographic conditions of analysis were similar to the GC conditions for the methyl esters analysis.

Phospholipid analysis

Modified method of Raheja et al. [20] was employed in the analysis of phospholipids. A weight of 0.01 g of the extracted fat was added to each test tube. To ensure complete dryness of the oil for phospholipids analysis, the solvent was completely removed by passing a stream of nitrogen gas on the oil. A volume of 0.40 ml of chloroform was added to the tube followed by the addition of 0.10 ml of chromogenic solution. The tube was heated at 100oC in water bath for about 1 min and 20 sec. The content was allowed to cool to the laboratory temperature and 5 ml of hexane was added and the tube shaken gently several times. The solvent and the aqueous layers were allowed to separate. The hexane layer was recovered and concentrated to 1.0 ml for analysis. The phospholipids were analysed using an HP 5890 powered with HP gas chromatograph (HP 5890 powered with HP ChemStation rev. AO9.01 [1206] software [GMI, Inc, Minnesota, USA]) fitted with a pulse flame photometric detector. Nitrogen was used as the carrier gas with a flow rate of 20-60 ml/min. The oven programme was: initial temperature at 50oC, first ramping at 10oC/min for 20 min (250oC), maintained for 4 min, second ramping at 15oC/min for 4 min (310oC) and maintained for 5 min. The injection temperature was 250oC whilst the detector temperature was 320oC. A polar (HP5) capillary column (30 m, 0.25 mm i.d., 0.25µm film thickness) was used to separate the phospholipids. Split injection type was used having a split ratio of 20:1. Hydrogen pressure was 20 psi and compressed air was 30 psi.The peaks were identified by comparison with standard phospholipids. For the purpose of ensuring the accuracy of the results obtained, the followings were carried out: standard chromatograms were prepared for sterols, phospholipids and fatty acids methyl esters which were then compared with respective analytical results; calibration curves were prepared for all the standard mixtures and correlation coefficient determination for each fatty acid parameter (36), same for sterols (7) and phospholipids (5). Correlation coefficient should be ≥0.95 for the result to be acceptable. It is a statistical index that shows the quality assurance of the calibration curve performed. It was performed with the Hewlett Packard Chemistry (HPCHEM) software. Fatty acids were listed with the chain length and double bond numbers. At the data source and reference database levels, values for individual fatty acids are usually expressed as percentages of total fatty acids since this is the most common form of analytical presentation. (It was used here.) At the user data base level, values per 100 g of food are required. (Value of each fatty acid present in 100 g of fish muscle was calculated.) At all levels of data management both modes of expression are useful for comparative evaluation. A conversion factor derived from the proportion of the total lipids present as fatty acids is required [21] for converting percentages of total fatty acids to fatty acids per 100 g of food. (Crude fat level was multiplied by a conversion factor of 0.80 to convert it to total fatty acids [21].) For fatty acids expressed in g per 100 g total fatty acids, precision is best limited to the 0.1 g/100 g level, with trace being set at <0.06 g/100 g of fatty acids [22].

Statistical analysis

Statistical analysis [23] was carried out to determine the mean, standard deviation, coefficient of variation in per cent. Also calculated were the chi-square (X2). The X2 values were subjected to the Table (critical) value at α = 0.05 to see if significant differences existed in the values of fatty acids between the samples.

Results

Table 1 depicts total lipid and calculated total lipid fatty acid levels of the samples on dry weight basis. The values of crude fat ranged between 0.42 – 8.92g/100g while the calculated total fatty acid levels ranged between 0.34-7.14g/100g. These values were averagely widely varied with the CV% of 87.3. Table 2 shows the saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) of the samples.

In all the samples, the following SFA recorded 0.00% value: C6:0, C8:0 and C10:0. Table 2 also contains polyunsaturated fatty acids (PUFA) composition of n-6 and n-3 in the samples. Among the n-6 family, C20:4 n-6 (arachidonic acid, AA) had a value 0.00% in all the samples while C18:2 (cis -9, 12) (linoleic acid) had the highest concentration in all the samples with values ranging from 27.5- 52.7% with a CV% of 29.0. Some calculated parameters and ratios were shown in Table 3. Table 4 contains fatty acid profiles (g/100g) of the samples as food sources. It showed the level of fatty acids when a particular quantity (g/100g) of sample oil is consumed as food. This type of information is required to be a able to calculate the energy contribution by each type of fatty acid. As expected, the concentration of the fatty as food went as (g/100g): SFA (0.17-1.25) > MUFA (cis) (0.07-1.18) > MUFA (trans) (3.4e-4 to 0.15) < PUFA (0.10 to 4.67). Table 5 shows the energy contribution of the fatty acids in the samples some notable energy contributions (kJ/100g) were as follows C16:0 (2.85-31.7), C18:0 (0.37 – 10.9) among the SFAs, however the contribution from the total SFA ranged between 6.22-46.2 kJ/100g. Among the MUFA values were: C18:1 cis-6 (1.14- 17.4) and C18:1 cis-9 (1.47-34.4) whereas total MUFAs contribution ranged between 2.64-45.6 kJ/100g. In the PUFA category, C18:3 (n-3), (0.12- 21.5), C18:2 (n-6), (3.42-139) and the total PUFA gave between 3.59-173kJ/100g. The phytosterol levels of the samples are depicted in Table 6. All the predominant animal sterols were in traces, they included (mg/100g): cholesterol (9.2e-5 to 1.99e-3), cholesterol (5.03e-6 to 4.88e-5), ergosterol (9.14e-4 – 1.44e-3), except 5-avenasterol with values higher than the adjudged trace (0.63- 1.77). On the other hand plant sterols were fairly highly concentrated in the samples (mg/100g): campesterol (2.35-15.7), stigmasterol (1.54-4.59) and sitosterol (19.3-351). Various concentrations of phospholipids in our samples are depicted in Table 7. The values ranged as follows: PE (1.13-2.53 mg/100g), PC (2.60-27.4 mg/100g), PS (1.45-4.52 mg/100g), LPC (1.00 1.89mg/100g) and PI (1.01- 9.18mg/100g) in the four samples.

Table 1. Crude fat, total fatty acids (%) and energy (kJ/100g) levels of A. melegueta, Zingiber officinale, A. melegueta Xylopic aethiopica

Parameter OO2 AT1 FK1 FK3 Mean SD CV% X2 REMARK
Crudefat 3.41 8.92 3.48 0.42 4.06 3.54 87.3 9.27 S
Total fatty acids* 2.73 7.14 2.78 0.34 3.25 2.83 87.3 7.42 NS
Energy (kJ/100g) 101 264 103 12.4 120 105 87.3 274 S

OO2 = Afromomum melegueta (big alligator pepper), AT1 = Zingiber officinale (ginger),

FK1 = Afromomum melegueta (small alligator pepper), FK3 = Xylopic aethiopica (Ethiopian pepper), X2=Chi – square at α=0.05, CV = coefficient of variation, S = significant, NS = not significant, *Crude fat x 0.80

Table 2. Fatty acids composition of A. melegueta, Z. officinale, A. melegueta X. aethiopica (%total fatty acid)

FA OO2 AT1 FK1 FK3 Mean SD CV%
C6:0 0 0 0 0 0 0 0
C8:0 0 0 0 0 0 0 0
C10:0 0 0 0 0 0 0 0
C12:0 0 0.26 0 6.65 1.73 3.28 190
C14:0 0 0.27 0 17.4 4.42 8.66 196
C16:0 26.1 12 25 22.9 21.5 6.47 30.1
C18:0 3.29 4.14 5.75 2.99 4.04 1.24 30.6
C20:0 0.15 0.4 0.14 0.05 0.19 0.15 79.1
C22:0 0.141 0.363 0.126 0.048 0.17 0.135 79.8
C24:0 0.02 0.05 0.02 0.01 0.03 0.02 57.7
TOTAL (SFA) 29.7 17.5 31 50 32.1 13.4 41.9
C14:1(cis-9) 0 0 0 0 0 0 0
C16:1(cis-9) 0.2 0.51 0.18 0.07 0.24 0.19 78.7
C18:1(cis-6) 17.2 2.38 16.5 9.16 11.3 6.98 61.7
C18:1(cis-9) 15.7 13 15.1 11.8 13.9 1.81 13
C20:1 (cis-11) 0.16 0.4 0.14 0.05 0.19 0.15 78.7
C22:1(cis-13) 0.05 0.13 0.04 0.02 0.06 0.05 80.5
C24:1(cis-15) 0.02 0.05 0.02 0.01 0.03 0.02 57.7
TOTAL (MUFA cis) 33.3 16.5 34 21.1 26.2 8.78 33.5
C18:1 (trans-6) 0.06 0.14 5.05 0.02 1.32 2.49 189
C18:1 (trans-9) 0.16 0.4 0.14 0.05 0.19 0.15 78.7
C18:1 (trans-11) 0.09 0.23 0.08 0.03 0.11 0.09 78
TOTAL Trans 0.3 0.77 5.27 0.1 1.61 2.46 153
TOTAL(cis and trans) 33.6 17.3 37.2 21.2 27.3 9.6 35.1
C18:3 (cis-9,12, 15) 1.56 8.16 1.47 0.96 3.04 3.42 113
C20:2 (cis-11,14) 0.02 0.06 0.02 0.01 0.03 0.02 66.7
C20:3 (cis-11,14,17) 0.09 0.15 0.08 0.03 0.09 0.05 54.7
C20:5 (cis-5,8,11,14,17) 0.07 0.18 0.06 0.02 0.08 0.07 85.6
C22:6 (4,7,10,13,16,19) 0.48
TOTAL (n-3 PUFA) 1.74 9.03 1.63 1.09 3.37 3.78 113
C18:2 (cis-9,12) 34.3 52.7 34.5 27.5 37.3 10.8 29
C18: 2 (trans-9,11) 0.07 0.17 0.04 0.02 0.08 0.07 83.2
C18:3 (cis-6,9,12) 0.5 3.05 0.06 0.24 0.96 1.4 146
C20:3 (cis-8,11,14) 0.06 0.15 0.05 0.02 0.07 0.06 80
C20:3 (cis-11,14,17) 0.09 0.24 0.08 0.03 0.11 0.09 82.3
C20:4 (cis-5,8,11,14) 0 0 0 0 0 0 0
C22:2 (cis-13,16) 0.02 0.05 0.02 0.01 0.03 0.02 66.7
TOTAL (n-6 PUFA) 35 56.3 34.7 27.8 38.5 12.3 37.9
PUFA total 36.7 65.4 36.4 28.9 41.9 16.1 38.4

Table 3. Calculated parameters from fatty acids of A. melegueta, Z. officinale, A. melegueta, X. aethiopica

Fatty acid OO2 AT1 FK1 FK3 Mean SD CV% X2 Remark
SFA 29.7 17.5 31.0 50.0 32.1 13.4 41.9 16.8
S
MUFA cis 33.3 16.5 32.0 21.1 25.7 8.23 32.0 7.91 S
MUFA Trans 0.30 0.27 5.27 0.10 1.49 2.52 169 11.5 S
MUFA Total 33.6 17.3 37.2 21.2 27.3 9.60 35.1 10.1 S
n-3 PUFA 1.74 9.03 1.63 1.09 3.37 3.78 113 12.7 S
n-6 PUFA 35.0 56.3 34.7 27.8 38.5 12.3 37.9 11.9 S
PUFA total 36.7 65.4 36.4 28.9 41.9 16.1 38.4 18.6 S
n-6/n-3 20.1 6.23 21.3 25.5 18.3 7.24 39.6 11.5 S
MUFA/SFA 1.13 0.99 1.20 0.42 0.94 0.35 37.7 0.40 NS
EPSI 1.09 3.78 0.98 1.36 1.79 1.33 71.6 2.95 NS
PUFA/SFA 1.24 3.74 1.17 0.58 1.68 1.40 83.5 3.60 NS
LA/ALA 22.0 6.46 23.5 28.6 20.1 8.27 41.1 13.6 S

OO2 = Afromomum melegueta (big alligator pepper), AT1 = Zingiber officinale (ginger),

FK1 = Afromomum melegueta (small alligator pepper), FK3 = Xylopic aethiopica (Ethiopian pepper), X2=Chi -square at α=0.05, CV = coefficient of variation, S = significant, NS = not significant

Discussion

The crude fat results in Table 1 were better than the values in sorghum (1.83g/100g), millet (1.10g/100g), maize (1.72g/100g) and rice (0.63g/100g) [24] but comparably lower than levels reported for three types of chillies consumed in Nigeria (10.8-12.1g/100g) [25]. The crude fat levels were relatively low and so the seeds as well as ginger could not be said to be major sources of dietary fat. The total fatty acid (TFA) profiles showed that Zingiber officinale (ginger) had the highest level of TFA (7.14g/100g) and the lowest in Ethopian pepper (Xylopic aethiopica) with a value of 0.34g/100g dry weight. Both crude fat and energy (kJ/100g) were significantly different in their groups when subjected to X² (chi-square) analysis at α=0-05 (Table 1). However, at the same level of confidence significant different also occurred in the total fatty acids of the examples.

Table 4. Fatty acid composition of A. melegueta, Z. officinale, A. melegueta , X. aethiopica (% total fatty acid)

Fatty acid OO2 AT1 FK1 FK3 Mean SD CV%
C6:0 0.00 0.00 0.00 0.00 0.00 0.00 0.00
C8:0 0.00 0.00 0.00 0.00 0.00 0.00 0.00
C10:0 0.00 0.00 0.00 0.00 0.00 0.00 0.00
C12:0 0.00 0.02 0.00 0.02 0.01 0.011 115
C14:0 0.00 0.02 0.00 0.06 0.02 0.03 141
C16:0 0.71 0.86 0.70 0.08 0.59 0.35 58.6
C18:0 0.09 0.30 0.16 0.01 0.14 0.12 87.9
C20:0 0.00 0.03 0.04 0.002 0.02 0.02 100
C22:0 0.00 0.03 0.04 0.002 0.02 0.02 100
C24:0 0.00 0.03 0.005 0.00 0.01 0.02 200
TOTAL (SFA) 0.81 1.25 0.86 0.17 0.76 0.47 62.1
C14:1(cis-9) 0.00 0.00 0.00 0.00 0.00 0.00 0.00
C16:1(cis-9) 0.06 0.04 0.05 0.00 0.04 0.03 65.7
C18:1(cis-6) 0.47 0.17 0.46 0.03 0.28 0.22 78.0
C18:1(cis-9) 0.43 0.93 0.42 0.04 0.46 0.37 80.4
C20:1 (cis-11) 0.00 0.03 0.04 0.00 0.02 0.02 100
C22:1(cis-13) 0.01 0.09 0.01 0.00 0.03 0.04 140
C24:1(cis-15) 0.00 0.03 0.00 0.00 0.01 0.02 200
TOTAL (MUFA cis) 0.91 1.18 0.890 0.89 0.07 0.48 63.2
C18:1 (trans-6) 0.02 0.01 0.14 0.00 0.29 0.48 165
C18:1 (trans-9) 4.2e-3 0.028 3.8e-3 1.8e-4 9.2e-3 0.013 142
C18:1 (trans-11) 2.4e-3 0.016 2.2e-3 1.0e-4 5.2e-3 7.3e-3 141
TOTAL Trans 8.1e-3 0.055 0.147 3.4e-4 0.052 0.067 128
TOTAL(cis and trans) 0.917 1.23 1.04 0.071 0.814 0.512 62.9
C18:3 (cis-9,12, 15) 0.043 0.582 0.041 3.2e-3 0.167 0.277 166
C20:2 (cis-11,14) 5.9e-4 4.0e-3 5.3e-4 2.5e-5 1.3e-3 1.8e-3 142
C20:3 (cis-11,14,17) 2.6e-3 0.011 2.3e-3 1.1e-4 4.0e-3 4.8e-3 120
C20:5 (cis-5,8,11,14,17) 1.9e-3 0.013 1.7e-3 7.7e-5 4.0e-3 5.7e-3 142
C22:6 (4,7,10,13,16,19) 0.034
TOTAL (n-3 PUFA) 0.048 0.644 0.046 3.62e-3 0.185 0.306 163
C18:2 (cis-9,12) 0.936 3.76 0.960 0.092 1.44 1.60 111
C18: 2 (trans-9,11) 1.8e-3 0.012 1.1e-3 7.4e-5 3.7e-3 5.5e-3 149
C18:3 (cis-6,9,12) 0.014 0.218 1.7-3 8.2e-4 0.058 0.106 182
C20:3 (cis-8,11,14) 1.6e-3 0.011 1.5e-3 6.7e-5 3.5e-3 5.0e-3 141
C20:3 (cis-11,14,17) 2.6e-3 0.017 2.3e-3 1.1e-4 5.5e-3 7.8e-3 142
C20:4 (cis-5,8,11,14) 0.00 0.00 0.00 0.00 0.00 0.00 0.00
C22:2 (cis-13,16) 4.8e-4 3.2e-3 4.5e-4 2.0e-5 1.0e-3 1.5e-3 141
TOTAL (n-6 PUFA) 0.955 4.02 0.969 0.094 1.51 1.72 119
PUFA total 4.67 1.01 0.097 1.69 2.03 120

Table 5. Energy distribution as contributed by the fatty acids of A. melegueta, Z. officinale, A. melegueta, X. aethiopica (values in kJ/100g)

Fatty acid OO2 AT1 FK1 FK3 Mean SD CV%
C6:0 0.00 0.00 0.00 0.00 0.00 0.00 0.00
C8:0 0.00 0.00 0.00 0.00 0.00 0.00 0.00
C10:0 0.00 0.00 0.00 0.00 0.00 0.00 0.00
C12:0 0.00 0.692 0.00 0.83 0.38 0.44 116
C14:0 0.00 0.72 0.00 2.16 0.72 1.02 141
C16:0 26.3 31.7 25.8 2.85 21.7 12.8 59.2
C18:0 3.32 10.9 5.92 0.37 5.14 4.48 87.2
C20:0 0.16 1.05 0.14 0.01 0.34 0.48 141
C22:0 0.142 0.958 0.130 6.0e-3 0.309 0.437 141
C24:0 0.018 0.119 0.016 7.5e-4 0.038 0.054 141
TOTAL (SFA) 30.0 46.2 32.0 6.22 28.6 16.6 58.0
C14:1(cis-9) 0.00 0.00 0.00 0.00 0.00 0.00 0.00
C16:1(cis-9) 0.202 1.36 0.18 8.5e-3 0.438 0.619 141
C18:1(cis-6) 17.4 6.28 17.0 1.14 10.4 8.06 77.1
C18:1(cis-9) 15.8 34.4 15.6 1.47 16.8 13.5 80.4
C20:1 (cis-11) 0.158 1.06 0.14 6.6e-3 0.343 0.485 141
C22:1(cis-13) 0.049 0.33 0.04 2.1e-3 0.106 0.151 141
C24:1(cis-15) 0.018 0.12 0.02 7.5e-4 0.038 0.054 141
TOTAL (MUFA cis) 33.6 43.6 32.9 2.62 28.2 17.7 62.9
C18:1 (trans-6) 0.056 0.375 5.20 2.4e-3 1.41 2.53 180
C18:1 (trans-9) 0.156 1.05 0.142 6.6e-3 0.340 0.481 142
C18:1 (trans-11) 0.089 0.594 0.080 3.7e-3 0.192 0.271 141
TOTAL Trans 0.301 2.02 5.42 0.013 1.94 2.49 128
TOTAL(cis and trans) 33.9 45.6 38.4 2.64 30.1 19.0 62.9
C18:3 (cis-9,12, 15) 1.57 21.5 1.51 0.12 6.19 10.3 166
C20:2 (cis-11,14) 0.022 0.148 0.020 0.001 0.048 0.068 142
C20:3 (cis-11,14,17) 0.095 0.404 0.085 0.004 0.147 0.176 120
C20:5 (cis-5,8,11,14,17) 0.069 0.465 0.063 0.003 0.150 0.212 142
C22:6 (4,7,10,13,16,19) 1.27
TOTAL (n-3 PUFA) 1.76 23.8 1.68 0.136 6.85 11.4 163
C18:2 (cis-9,12) 34.6 139 35.5 3.42 53.2 59.2 111
C18: 2 (trans-9,11) 0.066 0.438 0.039 2.7e-3 0.136 0.203 149
C18:3 (cis-6,9,12) 0.51 8.05 0.06 0.03 2.16 3.93 182
C20:3 (cis-8,11,14) 0.061 0.404 0.055 2.5e-3 0.130 0.184 141
C20:3 (cis-11,14,17) 0.095 0.636 0.085 4.0e-3 0.205 0.290 142
C20:4 (cis-5,8,11,14) 0.00 0.00 0.00 0.00 0.00 0.00 0.00
C22:2 (cis-13,16) 0.018 0.119 0.016 7.5e-4 0.038 0.054 141
TOTAL (n-6 PUFA) 35.3 149 35.8 3.46 55.8 63.6 119
PUFA total 37.1 173 37.5 3.59 62.7 75.0 120

Table 6. Phytosterol levels (mg/100g)of A. melegueta, Z. officinale, A. melegueta, X. aethiopica

Phytosterol OO2 AT1 FK1 FK3 Mean SD CV%
Cholesterol 1.99e-3 9.78e-5 9.20e-5 3.05e-4 6.21e-4 9.18e-4 148
Cholestanol 4.68e-5 5.03e-6 4.88e-5 3.46e-5 3.38e-5 2.02e-5 59.7
Ergosterol 1.14e-3 1.44e-3 1.15e-3 9.14e-4 1.16e-3 2.16e-4 18.6
Campesterol 12.2 15.7 3.91 2.35 8.54 6.44 75.4
Stigmasterol 4.59 4.38 2.76 1.54 3.32 1.44 43.4
5-avenasterol 1.55 1.64 1.77 0.63 1.40 0.519 37.1
Sitosterol 351 268 155 19.3 198 144 72.5
Total 369 290 163 23.8 211 151 71.5

Table 7. Phospholipids levels (mg/100g) of A. melegueta, Z. officinale, A. melegueta, X. aethiopica

Phospholipids OO2 AT1 FK1 FK3 Mean SD CV%
Phosphatidylethanolamine (PE) 1.30 2.53 1.13 1.16 1.53 0.67 43.8
Phosphatidylcholine (PC) 18.3 27.4 17.9 2.60 16.6 10.3 62.1
Phosphatidylserine (PS) 1.82 3.82 4.52 1.45 2.90 1.50 51.6
Lysophosphatidylcholine (LPC) 1.16 1.89 1.05 1.00 1.27 0.42 33.1
Phosphatidylinositol (PI) 1.01 1.04 9.18 7.99 4.81 4.39 91.4
Total 23.6 36.7 22.9 7.01 22.6 12.2 53.9

The most abundant fatty acid (FA) in nature is usually the palmitic acid (C16:0) and it is found in appreciable amounts in the lipids of animals, plants and lower organisms. It is present in amounts that vary from 10-40% in seed oils; in all the samples C16:0 was the highest concentrated SFA and the values varied from 12.0 – 26.1%. This observation was also similar to what was seen in chillies reported by Adeyeye et al. [25]. The C22:0 and C24:0 have not been implicated in enhancing the level of low density lypoprotein (LDL) cholesterol unlike myristic (C14:0) and palmitic acid (C16:0). C14:0 recorded 0.00% in small alligator pepper. The values of 17.5-50.0% (total SFA) were comparatively higher than the values of 16.6-18.3% reported for the grains of treated sorghum bicolour [26]. Stearic acid (C18:0) was the second most abundant SFA in nature, and again it is found in the lipids of most living organisms; this observation corroborated our present report where C18:0 values ranged between 2.99-5.75% as second most concentrated SFA of importance, it occurs in the highest concentrations in ruminant fats (milk fat and tallow) or in vegetable oils such as cocoa butter and of course in industrially hydrogenated fats. It can comprise 80% of the total fatty acids in gangliosides. Relatively high proportions of stearic acid can be subjected to enzymatic desaturation (forming oleic acid), in comparison to other SFA [27]. C20:0 (eicosanoic acid) can be detected at low levels in most lipids of animals, and often in those of plants and micro-organisms (Christie, 2011). The levels of C20:0 in our present samples ranged between 0.05- 0.40%

While saturated fatty acids obviously provide desirable properties to lipids in membranes by conferring rigidity where it is required, their nutritional value is a matter for debate, especially for those of medium chain-length. Most

nutritionists recommend keeping dietary intakes of saturated fats as low as possible regardless of chain-length. However some benefits have been attributed to SFA. They include: SFA constitute at least 50% of cell membranes, they give our cells necessary stiffness and integrity; they play a vital role in the health of our bones, for calcium to be effectively incorporated into the skeletal structure, at least 50% of the dietary fats should be saturated [28]. they lower lipoprotein (a), a substance in the blood that indicates proneness to heart disease [29], they protect the liver from alcohols and other toxins, such as Tylenol [30]; they enhance the immune system [31]; they are needed for proper utilization of essential fatty acids (EFA’s) elongated omega-3, FAs are better retained in the tissue when the diet is rich in SFA [26]; C16:0 and C18: are the preferred food for the heart, which is why the fat around the heart muscle is highly saturated [32], the heart draws on this reserve of fat in times of stress; short and medium-chain SFA have important antimicrobial properties, they protect us against harmful micro-organism in the digestive tract.

The total MUFA (trans) levels in the samples ranged as 0.10-5.27%. Tissues of ruminant animals, such as cows, sheep and goats, can contain a number of different 18:1 isomers. With the cis-isomers, 9- and 11-18:1 predominates as might be expected. 11t-18:1 makes up 50% of the trans-monoenes (which comprises) 10-15% of the total monoenes or 3-4% of the total fatty acids, but there are appreciable amounts of other isomers from 7t- to 16t- 18:1. Trans fatty acids (TFA) are generated when vegetable oils are partially hardened by hydrogenation to replace naturally occurring PUFAs in the diet [33]. Because TFA are typically monounsaturated, it was thought they exerted a neutral effect on cholesterol metabolism and other biological functions. However, more recent research had revealed a negative influence on lipoproteins and possibly other functions as well. As opined by Sundram et al. [34], to examine this point more directly, trans 18:1 n-9 ( elaidic acid) was compared head-to head with the most cholesterol – raising saturated fat and the neutral cis 18:1 n-9 (oleic acid) in humans. However in these results the elaidic values were negligible. The levels of total MUFAs in our present samples ranged between 17.3-37.2% with a CV% of 35.1. The averagely low CV% shows their closeness in values. Current nutritional thinking appears to be that dietary trans-monoenoic fatty acids, both from ruminant and from industrial hydrogenation processes, should be considered as potentially harmful and in the same light as SFA.

The PUFA values were comparably higher than the values reported for types of chillies consumed in Nigeria. [25] On the other hand the values in the present report favourably compared to the levels reported for some Nigeria citrus seed oils (29.0- 37.8%) [35] and in some cereals [24]. Among the n-3 PUFAs only ALA (C18:3, n-3, alpha linolenic acid) had a fairly high level ranging between 0,96-8.16%. In all the samples, the rest FAs of the group were of very low levels (0.01-0.18%). Mammals lack the ability to introduce double bonds in fatty acids beyond carbon 9 and 10, hence both n-6 and n-3 FAs are essential for man in the diet. In humans, arachidonic acid (C20:4,5,8,11,14) can be synthesized from LA by desaturation and chain elongation ( though some carnivores like cats, cannot do this, and require arachadonate in the diet) [36].

The total PUFA levels in the samples ranged between 28.9 – 65.4% with a CV% of 38.4. The highest value was in AT1 (Zingiber officinale). While the levels in the other three samples were lower than what was reported for some Nigerian seeds oils, the value in ginger was comparably close [35]. Conjugated linoleic acid (CLA) is a constituent of ruminant animals and exists as a general mixture of conjugated isomers of linoleic acid (LA). The cis-9, trans-11 CLA isomer (rumenic acid or RA) accounts for up to 80-90% of the total CLA in ruminant products [32]. The levels of CLA in our present samples ranged between 0.02 – 0.17% with a CV% of 88.9. In the consideration of balance among the PUFA, the issue of whether to include linoleic acid (18:2, n-6), linolenic acid (18:3, n-3) or longer n-3 fatty acids like eicosapentaenoic acid and docosapentaenoic acid must be considered. Both n-6 and n-3 families are essential fatty acids and both are important to health. The linoleic acid levels has the greatest impact on regulating the LDL/HDL ratio, whereas linolenic acid and its longer derivatives have a major influence over clotting mechanism, as well as stability of the heart against abnormal beating (arrhythmia) that can lead to sudden death. Diets enriched in 18:3 n-3 or 22:6 n-3 have been shown to exert a significant anti-CHD effect on human both in clinical and epidemiological studies [37]. The human brains need a high requirement for DHA, low DHA levels have been linked to low brain serotonin levels, which are connected to an increased tendency for depression and suicide. Several studies have established a correlation between low levels of n-3 fatty acids and depression. High consumption of n-3 PUFA is typically associated with a lower incidence of depression, a decreased prevalence of age-related memory loss and a lower risk of developing Alzheimer’s disease [38]. DHA was only present in two of the samples (ginger (ATI) with a value of 0.48% while not being detected in the other three samples. The relative proportion of SFA to MUFA has been shown to be an important aspect of phospholipid compositions and changes to this ratio have been claimed to have effects on such disease states as cardiovascular disease, obesity diabetes, neuropathological conditions and cancer [39]. For example, they have been shown to have cytoprotective action in pancreatic β-cells. Cis-monoenoic acids have desirable physical properties for membrane lipids in that they are liquid at body temperature, yet are relatively resistant to oxidation. They are now recognized by nutritionist as being beneficial in human diet. For example, oleic acid comprises a high proportion of the fatty acids of olive oil, a major fat component of the ‘Mediterranean diet’. The exception is erucic acid as there is evidence from studies with laboratory rats that it may adversely affect the metabolism of the heart [40]. Oleic acid (C18:1 cis-9), from Table 2 made up between 47.1-56.2% among the MUFA (cis) in the samples. The actual levels ranged between 11.8-15.7% when considered on individual basis. The values were comparably higher than the levels reported for three types of chillies grown in Nigeria with values 5.16-5.91% [25] and for raw and heat processed groundnut seeds (8.28-12.0%) [41]. There is epidemiological evidence that dietary MUFAs have been shown by controlled clinical studies to favourably affect a number of risk factors for CHD, including plasma lipids and lipoproteins, factors released to thrombogensis invitro LDL oxidative susceptibility (when compared with PUFA), and insulin sensitivity. In addition, Kris –Etherton [42] had earlier reported that compared with SFAs, MUFAs lower total and LDL cholesterol levels, and relative to carbohydrate, they increase HDL cholesterol levels and decrease plasma triglyceride levels. However, additional research is needed in humans and appropriate animal models to gain a better understanding of the effects of high –MUFA diets on antherogenesis [42]. A diet high in MUFA (versus a high-carbohydrate diet) improves glycemic control in individuals with NIDDM who maintain normal body weight. Individuals with elevated triglycerides or insulin also may benefit from a high-MUFA diet [42]. Petroselinic acid (C-18:1) occurs up to a level of 50% or more in seed oils of the Umbelliferae family, including carrot, parsely and coriander. It is of interest to note that the levels of petroselinic acid in our present samples are almost at par with oleic acid.

MUFA/SFA range was 1.13 (big alligator pepper), 0.99 (ginger), 1.20 (small alligator peppers) and 0.424 (Ethiopian pepper). The range being 0.42 – 1.20. The ratios recorded in our present samples were comparably lower than those of raw and processed groundnut seeds [41].

The n-6/n-3 range in all the samples were very much in favour of n-6 as can be seen in the range of values 6.23 – 25.5. Similar observations have also been made in the raw and processed groundnut seeds [41] and raw and processed Terminalia catappa [43]. According to Kinsella [44], problems associated with an excess of PUFA are exacerbated by the fact that most polyunsaturated fatty acids in commercial vegetable oil are in the form of double unsaturated (DUFA) omega-6 linoleic acid, with very little vital triple (TUFA) unsaturated omega-3

linolenic acid. Recent research has revealed that too much omega-6 in the diet creates an imbalance that can interfere with production of important prostaglandins. This destruption can result in increased tendency to form blood clots, inflammation, high blood pressure, irritation of the digestive tract, depressed immune function, sterility, cell proliferation, cancer and weight gain [45]. The present report showed that n-6/n-3 ratio fell within the range given for the most Western diets (15:1 and 20:1) [46].

The LA/ALA values in the samples were 22.0:1 (big alligator pepper), 6.46:1 (ginger), 23.5:1 (small alligator pepper) and 28.6:1 (Ethiopian pepper). Our LA/ALA results within a range of 22.0-28.6 indicated a high degree of deviation from 7:1 as recommended normal ratio [37]. The ratio of PUFA/SFA (PS ratio) is important in determining the detrimental effects of dietary fats. The higher the P/S ratio the more nutritionally useful is the oil. This is because the severity of atherosclerosis is closely associated with the proportion of the total energy supplied by SFA and PUFA fats [47]. The PUFA/SFA levels in our present report ranged between 0.58-3.74. These levels tended towards PUFA far more than SFA with the exception of Ethiopian pepper in which the concentration shifted to SFA more than PUFA. The values listed above were much in favour of LA. The available tissue composition of AA can be lowered by reducing dietary intakes of the 18-carbon precursor, LA. Conversely, it has been known since the early 1960s that greater dietary intakes of LA increase tissue concentrations of AA, thereby reducing tissue concentration of EPA and DHA [48]. The essential PUFA status index (EPSI) values in the samples ranged between 1.0 – 3.78. The values were shown to be good in three of the samples with the exception of small alligator pepper with a value lower than one and the reason for the lower value was due to higher value of MUFA than PUFA in the sample.

With respect to the calculated parameter ratio, except MUFA (IFA, ESPI and PUFA/SFA all other parameters were significantly different among the samples when subjected to X2 (Chi-square) analysis of α = 0.05 (Table 4).

In the samples, total energy intake from these samples as contributed from SFA was greater than 10% E but the recommended range (acceptable macronutrient distribution range) for PUFA is 6.11% E [49] which is less than our values, the indication therefore is that our sample could lead to the replacement of SFA with PUFA (n-3 and n-6) in the diet.

The cholesterol lowering effect of dietary plant sterols (phytosterols) has been studied since the 1950’s and is well known [50]. Earlier studies showed that large amounts of sitosterol (≥10g/d) lowered serum cholesterol levels by 10-20%. The dosage and chalky taste of sitosterol limited its uses especially with the advent of the more powerful, well tolerated, lipid lowering 3-hydoxy-3-methylglutanyl enzyme A reductase inhibitors. Grundy and Mok [51] subsequently demonstrated that 3g/d of sitosterol was sufficient to lower serum cholesterol levels. They suggested that plant sterol could be considered a form of dietary treatment rather than a drug to lower cholesterol because plant sterols are naturally present in plant based foods. The major plant dietary sterols are sitosterol (C-29), sampesterol (C-28) and stigmasterol (C-29). These represent less than 50% of the total intake of sterols in the Western diets; the remainder is cholesterol [52]. Plants sterols have been reported to interfere with the uptake of both dietary and biliary cholesterol from the intestinal tract in humans [53]. The reason for this is not fully understood, however plant sterols appear to decrease the solubility of cholesterol in the oil and micellar phases, thus displacing cholesterol from bile salt micelles and interfering with its absorption [54]. The level of sitosterol in our present samples compared favourably with the levels reported for three types of chillies consumed in Nigeria [25] and in raw and processed groundnut seeds flour [41].

Phospholipids intervene in prostaglandin signal pathways as raw material used by lipase enzymes to produce the prostaglandin precursors. In plants they serve as the raw material to produce jasmonic acid, a plant hormone similar in structure to prostaglandins that mediate defensive responses against pathogens. The quantities of phospholipids in the human diet are not fully known. The total phospholipids intake of eight healthy Swedish women ranged from 1.5-2.5 mmol/day. Of the total dietary fatty acids, 13-33mg/g were consumed as phospholipids [55]. Further research has been carried out on the consumption of phosphatidylcholine and its group chlorine. Zeisel et al. [56] estimated that the adult population in the United States consumed about 6g of phosphatidylcholine per day. Phosphatidylcholine in our present report ranged between 2.60-27.4mg/100g. In all the samples phosphatidylcholine had the highest concentration. There is evidence that phospholipids influence the course of liver disease that occurs in connection with excessive alcohol corruption. Phosphatidylcholine is effective in ameliorating or even curing liver diseases. The second most concentrated phospholipids in our sample is phosphatidylserine ranging between 1.45-4.52 mg/100g. There is better evidence that phosphatidylserine influences cognition. Phosphatidylserine plays an important role in the function and homeostasis of neuronal cell membranes. Phosphatidylserine is able to improve age associated behavioural alteration in animal models, so it was thought that it may also have a positive impact on cognition in humans, particularly on those functions that are impaired during aging, such as memory and language achievement, as well as learning and concentrative [57, 58]. Therefore it was assumed that phosphatidylserine may be useful in the prevention and treatment of age related cognitive decline such as Alzheimer’s disease, and in depression and other cognitive disorders [59].

Conclusion

The plant samples (big and small alligator pepper, ginger and Ethiopian pepper) were low in total fatty acids, hence their consumption as food sources may not load the body with high fat. C12:0 and C14:0 were low (0.00 – 0.27%), thereby removing the fear that they might promote hearts diseases. SFA and MUFA values were close but generally lower than PUFA in the samples. Phospholipids were generally low in all the samples. Sitosterol was highly concentrated in the samples, this sterol had been found to be very good in the prevention of the absorption of cholesterol.