Allium Species, Ancient Health Food for the Future?

This book presents the wisdom, knowledge and expertise of the food industry that ensures the supply of food to maintain the health, comfort, and wellbeing of humankind. The global food industry has the largest market: the world population of seven billion people. The book pioneers life-saving innovations and assists in the fight against world hunger and food shortages that threaten human essentials such as water and energy supply. Floods, droughts, fires, storms, climate change, global warming and greenhouse gas emissions can be devastating, altering the environment and, ultimately, the production of foods. Experts from industry and academia, as well as food producers, designers of food processing equipment, and corrosion practitioners have written special chapters for this rich compendium based on their encyclopedic knowledge and practical experience. This is a multi-authored book. The writers, who come from diverse areas of food science and technology, enrich this volume by presenting different approaches and orientations.

and Ayuso (2005). The vitamin C content was analyzed with 2, 6-dichloroindophenol titrimetric method. Total anthocyanidins were determined using the Reay, Fletcher and Thomas (1998) method. Colorimetric quantification of total carotenoids was determined, as described by Mackinney (1941). Allicin determination was based on Miron et al. (2002) method. Various concentrations (1 µg/ml up to 10 mg/ml) of A. roseum extracts were used to determine the antimicrobial and antifungal activity. Minimum inhibitory concentration (MIC) values were determined by a micro-titre plate dilution method. The assessment of radical scavenging activity was determined using ABTS (2, 2'-Azino-(bis-3-ethylbenzthiazoline-6-sulfonic acid) di-ammonium salt) radical scavenging activity of the methanolic extracts was determined according to Re, Pellegrini, Proreggente, Pannala, Yang and Rice-Evans (1999). The results were expressed in terms of Trolox equivalent antioxidant capacity (TEAC). The antioxidant activity of the extracts was also evaluated using the DPPH (2, 2-diphenyl-2-picrylhydrazyl) free radical specrophotometrically according to Fattouch et al. (2007). All analysis mentioned were effected with quality control, than a proper sampling plan was followed with representative samples from the geographic area studied and sufficient replications of the sample were used to ensure statistically reliable and valid data. The analyses of the nutrient contents samples were made in our laboratory where ISO/CEI 17025 (2005) was respected to assure the quality of results.

Nutritional composition
The proximate chemical and nutritional composition of A. roseum edible part collected from Tunisia is listed in Table 1

Water content and pH
Water content is important because it affects the plant's properties. Compared to related vegetables, the A. roseum water content is lower than that of A. porrum varing from 83 to 89% (Tirilly and Bourgeois, 1999) and the A. cepa (89%) (Dini et al., 2008). The A. roseum is rather neutral (pH = 6.80 ± 0.05) compared to that of garlic (pH = 6.05) (Haciseferoğullari et al., 2005).

Sugars, proteins, fibres and lipids
Soluble carbohydrates represent the most abundant A. roseum leaves nutrients class (> 30%); as has also been observed in onion bulbs (Moreau et al., 1996) and garlic (Haciseferoğullari et al., 2005). The total carbohydrates content in this species calculated by difference is 54.2 g/100 g DW. Compared to the carbohydrates content of A. porrum (5 to 11%) (Tirilly and Bourgeois, 1999) and to aerial parts of other Alliums (5 to 12%) (Brewster, 1994), the leaves of A. roseum are rich sources of soluble carbohydrates. Dietary fibres are considered as unavailable carbohydrates, but nonetheless they still play a very important role in maintaining good health. Interestedly, A. roseum aerial part fibres content was higher than that reported for A. cepa bulb (1.7%), the edible part of the vegetable. Rosy garlic leaves proteins rate is relatively high compared to A. sativum bulbs (9.3%) and A. cepa (1.7%) (Haciseferoğullari et al., 2005;Dini et al., 2008). Fats accounted for 0.68% of the fresh weight of A. roseum, making them the least abundant class of nutrients. Yet this was higher than typical values of <0.5% fresh weight basis for most plant tissues, and also compared to most Allium plants. Where onion, leek and garlic contain 0.15%, 0.25% and 0.42%, respectively, as reported by Haciseferoğullari et al., (2005) and Tsiaganis et al., (2006).

Minerals
A. roseum is characterized by high ash content (Table 1) including macro and micro elements ( Table 2). Allium ash content ranges from 0.6 and 1.0% and higher values are associated to high dry matter content (Brewster, 1994). The mineral element composition of A. roseum exhibited a higher concentration of potassium than calcium and magnesium (Table 2). Minerals are important as constituents of bones, teeth, soft tissues, haemoglobin, muscle, blood and nerve cells and are vital to overall mental and physical well being (Jouanny, 1988). The high content of potassium in A. roseum is nutritionally significant in since it contributes to the control of hypertension which results in excessive excretion of potassium (Dini et al., 2008). Calcium is found at relatively high concentration in A. roseum (Table 2). Onion leaf calcium concentration (2540 mg/100 g fresh weight) (Boukari et al., 2001) is much higher than that of A. roseum leaves but bulb calcium concentration (45 mg/100 g fresh weight) (Adrian et al., 1995) is much lower. Therefore, calcium concentration in A. roseum is between that of onion leaves and bulbs. A. roseum can be considered as a source of calcium for human nutrition. This is important since calcium mineral deficiency is a world-wide problem; particularly in developing countries where the daily average intake is very low, ranging between 300 and 500 mg for adults (Boukari et al., 2001). The low sodium content of A. roseum and consequently low Na/K ratio (0.03) is another indication that A. roseum consumption would reduce the incidence of hypertension (Iqbal et al., 2006). A. roseum leaves also contains several oligo-elements including iron, zinc, copper and manganese. These values are similar to, but higher than, those of Haciseferoğullari et al., (2005) in A. sativum. The iron content of 'rosy garlic' was somewhat higher than that of A. cepa (8.1 mg/ 100 g) (Moreau et al., 1996). The magnesium, iron and phosphorous levels are adequate. Cadmium, lead and chromium were below the detection limit, as observed by Moreau et al., (1996)

Fatty acid composition
The fatty acid composition of A. roseum leaves is given in Table 3. Chromatographic analysis revealed twelve compounds. Unsaturated fatty acids accounted for most of the fatty acids (85 %) and were represented mainly by linolenic, linoleic, oleic and gadoleic. Five saturated acids (palmitic, stearic, myristic, arachidic and margaric), accounted for ~15% of the total fatty acids. Myristoleic, palmitoleic and heptadecanoic acids were found as minor compounds. The overall fatty acid profile of A. roseum reveals a good source of the nutritionally essential linolenic and oleic acids (Zia-Ul-Haq et al., 2007). Linoleic and linolenic acids are the most important essential fatty acids required for growth, physiological functions and maintenance (Pugalenthi et al., 2004). While the major fatty acid in A. roseum was linolenic acid, linoleic acid was most abundant in onion, garlic and leek where it represents about 50% of the total (Tsiaganis et al., 2006). The same authors demonstrated that garlic oils contain relatively high levels of linoleic acid, and that myristoleic acid (C 14:1 ) was absent in onion. As a consequence, the A. roseum fatty acid composition quality is comparable to that of A. sativum (Tsiaganis et al., 2006). It could be concluded that fatty acid composition varies within the species. We may note that the most abundant fatty acids are similar to those found in the oil of other Allium species. The less abundant fatty acids are present in A. roseum but at a lower concentration than reported by Tirilly and Bourgeois (1999) in A. porrum, Moreau et al. (1996) in A. cepa and Tsiaganis et al. (2006) in A. sativum. Overall, the A. roseum fatty acid composition was not qualitatively different from that of the other species.

Bioactive compounds
The content of potential health-promoting substances, flavonoid, total phenolic content, vitamin C, tannin, anthocyanidin, carotenoids and allicin in the wild A. roseum growing in the arid region of Tunisia is listed in Table 4.

Phenolic compounds, flavonoids, anthocyanidins, carotenoids and vitamin C contents
Total phenolic content of A. roseum expressed in equivalent catechol was higher than that reported for garlic (61.8 mg/100 g FW) and onion (31.0 mg/100 g FW) (Kaur and Kapoor, 2002). Although, shallots had the highest total phenolic content (114.7 mg/100 g) among the bulb onion varieties tested by Lanzotti (2006). However, this content is lower than that of rosy garlic leaves. Significant correlations were observed between the total phenolic content of A. roseum, and antioxidant activity, suggesting that phenolic compounds would be the major contributors to the antioxidant capacity of A. roseum (Najjaa et al., 2011a). Moreover, tannins and flavonoids were detected by several other authors and are usually less abundant in several other species of Allium (A. cepa, A. ascalonicum, A. sativum) (Bozin et al., 2008;Zielinskaa et al., 2008). Flavonoids are important secondary plant metabolites. The flavonoids content of rosy garlic is seven time that of garlic (0.5 mg/100 g) (Miron et al., 2002). Allium species are among the richest sources of dietary flavonoids and contribute significantly to the overall intake of flavonoids (Slimestad et al., 2007). In vitro and in vivo pharmacological tests have shown that flavonoids exhibit the following variety of actions: (i) antioxidative (Boyle et al., 2000); (ii) reduction of cardiovascular disease (Janssen et al., 1998) and (iii) reduction of carcinogenic activity (Steiner, 1997).

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The high A. roseum vitamin C content (1523.35 mg/100 g DW) may be an important reason that it has been reputedly used as a traditional Tunisian medicine for treating rheumatism and cold. Furthermore, its high vitamin C content confers considerable nutritional value. A. roseum leaves had high anthocyanidin content (1239.62 µg/100 g DW). Much is known about the anthocyanins of A. cepa bulbs, and leaves of A. victorialis and A. schoenoprasum (Terahara et al., 1994;Fossena et al., 2000;Slimestad et al., 2007). Moreover, A. roseum had a typical carotenoids content (Table 4) of leafy vegetables, which is higher than those of legumes and fruits (Combris et al., 2007).

Allicin content
Garlic antibacterial bioactive principal was identified as diallylthiosulphinate and was given allicin as trivial name since 1944. This bioactive substance is also detected in A. roseum with a concentration equivalent to 0.0328 µg/mL. This result is similar to that mentioned by Miron et al. (2002) in garlic (0.0308 µg/mL). Allicin (diallylthiosulfinate) is the most abundant organosulfurous compound, representing about 70% of the overall thiosulfinates formed upon garlic cloves crushing (Miron et al., 2002).

Antioxidant activity
The antioxidant activities of leaf extracts were assessed and confirmed using two functional analytical methods based on the radicals (ABTS and DPPH) scavenging potential, as recommended by Sànchez-Alonso et al., (2007). A good correlation was found between DPPH and ABTS methods (R 2 =0.827), indicating that these two methods gave consistent results. The extracts obtained were all able to inhibit the DPPH, as well as ABTS radicals ( Table 5). The antioxidant potential was 378.89 mg Trolox/100g DW with the DPPH method, and 399.99 mg Trolox/100g DW with the ABTS. In comparison to previous data based on the ABTS scavenging capacity, A. roseum leaf extracts were comparable or higher than other investigated species known to be rich in antioxidants including strawberry (25.9), raspberry (18.5), red cabbage (13.8), broccoli (6.5), and spinach (7.6) (Proteggente et al., 2002). Significant correlations were observed between the TPC of A. roseum, and antioxidant activity (R 2 =0.828 for TPC vs. DPPH and R 2 =0.925 for TPC vs. ABTS), suggesting that polyphenolic compounds are the major contributors to the antioxidant capacity of A. roseum.
Regarding the favourable redox potentials and relative stability of their phenoxyl radical, these biomolecules are considered to be human health promoting antioxidants (Acuna et al., 2002).

Antibacterial activity
The in vitro antibacterial effects of the A. roseum extracts obtained with the methanolic extract values are presented in Table 6. The results showed that A. roseum extracts have great potential as antimicrobial agent against the tested bacteria. C. albicans and C. glabrata, were the most sensitive tested organisms to the extract with the MIC values were 0.63 and 2.5 mg/ml, respectively. The strong antifungal activity was observed against C. albicans and C. glabrata may be related to the high level of polyphenols content. Cai et al. (2000) showed that several classes of polyphenols such as phenolic acids, flavonoids and tannins serve as plant defence mechanism against pathogenic microorganisms. In fact, the site and the number of hydroxyl groups on the phenol components increased the toxicity against the microorganisms.

Conclusion
This study revealed that A. roseum var. odoratissimum growing in Tunisia had a high soluble carbohydrates, crude protein and dietary fibre contents, compared to other Alliums. Its mineral content was high in potassium, and calcium. The mineral composition of 'rosy garlic' is sufficient in Ca, P, K, Cu, Fe, Zn and Mg so that it can meet many macronutrient and micronutrient requirements of the human diets. As a consequence, a diet based on A. roseum would help in preventing deficiencies in potassium, calcium, iron and magnesium. Furthermore, edible part oil included 15% saturated and 85% unsaturated fatty acids. Linolenic acid and palmitic acid were the most abundant unsaturated and saturated fatty acids, respectively. This fatty composition confers to the A. roseum oil considerable nutritional value, acting on physiological functions and reducing cardiovascular, cancer and arthroscleroses diseases occurrence risk. The most abundant phytonutrients found in A.
www.intechopen.com roseum (polyphenolic compounds, flavonoids, anthyacinidins, vitamin C and allicin) exhibit a positive effect on human health as antioxidants and antibacterial compounds. Since the chemical composition of A. roseum has not been reported before, this report provides a starting point for comparison to the other Allium genus vegetables and it confirms the potentially important positive nutritional value that A. roseum can have on human health. Since A. roseum is a rich source of many important nutrients and bioactive compounds responsible for many promising health beneficial physiological effects, it may be considered a nutraceutical that serves as a natural source of necessary components to help fulfil our daily nutritional needs and as a functional food as well as in ethnomedecine .