Effects of Raphia sudanica Mesocarp and Arrowroot (Tacca involucrata) Flour Incorporation on the Chemical Composition of Sorghum Composite Spaghetti

Obesity and food allergy (celiac disease) are serious public health problems, which should be addressed through encouraging the consumption of foods with high amount of low digestible carbohydrates and gluten free. Obesity arises through an imbalance between energy intake and energy expenditure, so it is important for products to have a balanced nutritional composition. Spaghetti is low in sodium, iron, fat, lysine, threonine and vitamins but a rich source of complex carbohydrates. The study evaluated the mineral elements, phytochemical, amino and fatty acids composition and sensory properties of sorghum/Raphia sudanica/Tacca involucrata spaghetti. The iron, zinc, potassium and calcium contents of the composite spaghetti samples increased with every 5% addition of Raphiasudanica mesocarp flour while the magnesium and sodium contents decreased. The total flavonoids, polyphenols, amino and fatty acids contents were also elevated with every 5% addition of Raphia sudanica mesocarp flour. Spaghetti sample 200:50:100 g was generally the most accepted by consumers. Raphia sudanica mesocarp flour is a rich source of mineral elements, polyphenols, amino and fatty acids. Its use as a food fortificant may improve the nutritional and health status of man.


Introduction
Pasta is a popular convenience food worldwide, prepared from durum wheat using extrusion cooking. Pasta produced with wheat has better quality characteristics. In pasta processing, gluten is mainly responsible for the formation of structure and considered the most significant factor to pasta cooking quality [1] [2]. Researchers have used other grains or pseudo cereals to partially or fully replace durum semolina to prepare gluten free (GF) or low glycemic index pastas for special nutrition [3] [4] [5]. People with specific genetic nature suffer from celiac disease (with a prevalence of 5%) which is usually manifested as a digestive malfunction of the intestines caused by the presence of gluten [6] [7]. The only effective treatment is a life-long gluten free diet [8] [9] or exclusion of the intake of storage proteins found in wheat, rye, barley and oats from their diet [10]. The main reason for the more recent spread of different pasta types is an awareness of consumers about nutrition, with relation to good health and an overall healthy lifestyle [11] [12]. Pasta is usually considered a healthy food when fortified with fibre, and less commonly, it is associated with a high content of minerals, such as calcium. Consumers today are increasingly interested in foods with health-promoting ingredients [13] [14] and food with nutrition and/or health claims on their labels, which are designed to offer useful information to the consumer about the health benefits of a product, while current legislation protects consumers from misleading and false information [15].
The gluten free nature of sorghum makes it appropriate food for those with celiac disease or other forms of allergies or wheat intolerance [16]. Sorghum (Sorghum bicolor (L.)) is an important staple food crop in sub-Saharan Africa.
Its slow digestibility, rich polyphenolic, antioxidant constituents and gluten free content have been harnessed in the production of several food products [17] [18]. Previous research has shown that minimum amount of sorghum can be used to produce noodles [19] [20] and pasta with combination of other cereals [21].
Raphia sudanica is an economically useful plant in Africa that produces palm sap which is fermented and drank as alcoholic beverage [22]. The oily mesocarp of the fruit is used in traditional medicine for its laxative and stomachic properties and as a linimat for pains. The ripe fruits are cooked and the mesocarp eaten in north-central, Nigeria. It is greatly underutilized and exploited in the food industry.
Arrowroot (Tacca involucrata) is a wild edible plant whose tubers contain starch which is processed into flour and used in the preparation of stiff starch porridges [23]. It is of the family Dioscoreaceae but formerly classified under the family Taccaceae [24]. Arrowroot has relatively high amounts of resistant starch which is non-digestible and therefore acts as fiber [25]. Its incorporation in spaghetti production may reduce the risks of obesity, cardiovascular diseases and diabetes, in addition being gluten free, may replace wheat in certain food applications to reduce the incidence of celiac disease (CD) or other allergic reactions to gluten [26].
The nutritional value of pasta is not very high as it is rich in starch and devoid of dietary fibre. Incorporation of high fiber material enhances the nutritional and functional quality of pasta [27]. Keeping in view the above findings of researchers, the study evaluated the mineral elements, phytochemical, amino and fatty acids composition and sensory properties of sorghum/Raphia sudanica/Tacca involucrata spaghetti.

Sources of Material
Sorghum grains and Arrowroot (Tacca involucrata) flour were purchased from Makurdi while fresh Raphia sudanica fruits were purchased from Kastina-Ala all located in Benue State, Nigeria.

Sorghum Flour Production
Sorghum grains were cleaned to remove extraneous plant parts and stones, washed and sun dried (5 hr). This was followed by dry milling (hammer mill) and sieving (0.2 mm mesh screen). The flour was packaged in air tight plastic container until needed.

Production of Raphia sudanica Flour
Fresh Raphia sudanica fruits were peeled and sun dried (72 hr) to constant weight. The dried fruits mesocarp were separated from the nuts, dry milled (hammer mill), sieved (0.2 mm mesh screen) and packaged (air tight plastic container) until needed.

Blends Formulation
Sorghum and Raphia sudanica mesocarp flours were blended on percentage basis as shown in Table 1. The quantity of Arrowroot flour (used as a binding and gelling agent) was kept constant while that of sorghum and Raphia sudanica mesocarp flour were varied by 5%.

Production of Sorghum/Raphia sudanica/Tacca involucrata Composite Spaghetti
Three hundred and fifty grams of sorghum/Raphia sudanica/Tacca involucrata composite flour was stirred into 220 ml warm water (85˚C) in an aluminum pot with application of heat on a gas cooker for five minutes, to form homogeneous dough. Thereafter, the dough was kneaded in a stainless bowl until soft and smooth, extruded using Marcato Atlas pasta machine (model 190, Italy) through 12 mm size screw hole. The extruded spaghetti was dried at ambient temperature.

Mineral Elements Determination
The iron, zinc, magnesium, calcium and manganese contents of the composite spaghetti were determined using atomic absorption spectrophotometry (Buck 210) while sodium and potassium contents were determined using flame

Fatty Acids Determination
The lipids were extracted from samples by Soxhlet extractor using hexane as a solvent. Fatty acids were transformed into methyl ester according to the ISO procedure [29]. The fatty acid methyl esters (FAMEs) were extracted with petroleum ether and were analyzed by high pressure liquid chromatography (HPLC) (Buck scientific BLC 10/11 USA) equipped with a flame ionization detector and integrator. The mobile phase is (59:41) acetonitrile: 2-propanol and the column (Prevail C-18.5 u, 150 × 4.6 mm) flow rate was 1 mL/min. The oven temperature was maintained at 210˚C for 45 min. The fatty acids were identified by comparing their retention times with those of standards [30].

Amino Acids Determination
The defatted flour samples from fatty acid determination were utilized to esti-

Sensory Evaluation
Sensory evaluation of the cooked spaghetti was conducted using 7 point hedonic scale (1 = dislike very much and 7 = like very much). Twenty (20) panelists evaluated the spaghetti samples for appearance, colour, taste, flavor, texture and overall acceptability [32].

Cooking Procedure
Pasta samples were dried to constant weight at 90˚C for 2 -3 h. One hundred and fifty grammes of dry pasta were added to 500 ml distilled boiling water free of sodium chloride and cooked for 5 minutes. The cooked pasta was drained and surface water removed by keeping over a thin muslin cloth. The cooked spaghetti samples were kept in food warmers for use in sensory analysis.

Statistical Analysis
The data obtained was subjected to Analysis of Variance (ANOVA) at 5% level of significance, using SPSS software version 25.0. Table 2 presents the mineral elements content of sorghum/Raphia sudanica/Tacca involucrata composite spaghetti. The result showed that, Raphia sudanica mesocarp flour characterized with its high mineral contents improved the mineral contents of the composite spaghetti blends, especially at a higher replacement level. The iron contents of composite spaghetti blends were higher than 0.45 -0.56 mg/100 g iron contained in maize/sorghum/water melon seeds composite spaghetti blends [32]. The iron contents of this study were however lower than 8.426 -23.936 mg/100 g contained in rice/dried banana composite spaghetti but similar to those of rice/fresh banana and rice/fresh banana pre-treated with ascorbic acid composite spaghetti [33] Moisture reduction has been reported to cause concentration in nutrients profile of dehydrated products [34]. The high iron contents of this study are of health significance in promoting haemoglobin formation and transportation of oxygen in the body.

Mineral Elements Composition of the Composite Spaghetti
The zinc contents of the study were higher than 0.64 mg/100 g to 0.80 mg/100 g reported for wheat semolina/guava seed pasta [35]. The differences in the zinc content between the two composite spaghetti blends may be due to differences  in iron contents of the cereals (sorghum and wheat) and fruits (raphia and guava) used in their production. It may also be due to differences in the sensitivity of analytical methods used in zinc determination and production procedures used in spaghetti production.
The magnesium content of this study were higher than 5.23 -5.66 mg/100 g reported for maize/sorghum/water melon seeds spaghetti [32] but lower than 122.19 -148.35 mg/100 g contained in wheat semonila/guava composite spaghetti [35]. The magnesium contents of the composite spaghetti were inversely proportional to Raphia sudanica mesocarp flour content. Its levels in the composite spaghetti may be used in the management of anxiety and stress and in relieving insomnia, due to its enzymatic role in releasing hormones that calm the body and induce sleep.
The potassium content of the composite spaghetti diverged from 685.32 mg/100 g (AGE1) -952.32 mg/100 g (AGE5). The use of wheat/guava composite in spaghetti production gave similar increases in potassium contents [34] but contradicts decreases in potassium contents of maize/sorghum/water melon seeds, maize/water melon seeds and sorghum/water melon seeds spaghetti blends [32]. Five hundred (500 g) grammes of the composite spaghetti blends may provide 4700 mg recommended daily intake of potassium to 14 years old female and male. The high potassium levels may be harnessed in the management/treatment of hypertension and other cardiovascular diseases of man. Potassium has been reported to reduce tension in blood vessels and ensure proper distribution of oxygen to vital organ system [36]. It has also been reported to protect against cardiovascular diseases [37], treat hypoglycemia and kidney dis-  [39]. The sodium contents of this study were higher than 0.24 -0.35 mg/100 g contained in maize/sorghum/water melon seeds spaghetti [32] but lower than 650.76 -702.74 mg/100 g contained in wheat semolina/guava seeds composite pasta [35].
The calcium content of the composite spaghetti ranged from 132.54 mg/100 g (AGE1) -162.04 mg/100 g (AGE5). The high calcium contents of the composite spaghetti blends may be employed in the dietetic management/treatment of calcium induce osteoporosis/osteomalacia in humans. The increased calcium content of this study was in agreement with increase in calcium content of maize/sorghum/water melon composite pasta [32]. Calcium is important in boosting bone health and improving dental health. It is important in treating obesity, colon cancer, and heart and kidney disorder.

Sorghum/Raphia sudanica/Tacca involucrata Composite Spaghetti Phytochemicals [40]
The phytochemical composition of the composite spaghetti blends is presented in Table 3. The total flavonoids and phytosterols contents of this study were significantly elevated for every 5% increase in Raphia sudanica mesocarp flour, indicating it to be a good source of flavonoids (31.66 mg/100 g) and phytosterols (64.54 mg/100 g). Flavonoids help to fight against Parkinson's disease, diabetes mellitus and lower blood pressure, and risk of stroke [41]. The increases in total polyphenol contents of the study were higher than 196.95 -227.80 mg/100 g of dried banana fortified pasta [33]. Polyphenols are important in preventing and reducing the progression of diabetes, cancer and neurodegenerative and cardiovascular diseases. They also act as prebiotic that boost health, weight management and disease prevention.

Amino Acids Composition of Composite Spaghetti Samples
The amino acid content of the composite spaghetti blends is presented in Table  4. The total amino acids content in the sorghum/arrowroot and sorghum/raphia sudanica mesocarp/arrowroot pasta were 67.37 mg/100 g and 68.69 -88.26 mg/100 g of dry matter, respectively. The protein content of the composite spaghetti consisted of 10 essential and 8 non-essential amino acids with threonine, phenylalanine, tryptophan, valine, leucine and arginine representing 31.91% of essential amino acids while glutamic and aspartic acids represented 23.69% of the non-essential amino acids. The amino acids contents of the composite spaghetti increased with every 5% replacement of sorghum flour. The increment in essential amino acid contents with sorghum flour replacement was in the order of methionine < histidine < isoleucine < lysine < tryptophan < threonine < phenylalanine < valine < arginine < leucine. The non-essential amino acids increased the order of cytosine < proline < alanine < serine < glycine < tyrosine < aspartic acid < glutamic acid.   The replacement of sorghum flour with Raphia sudanica mesocarp flour in sorghum pasta production significantly increased lysine content, from 2.03 mg/100 g (control) to 2.62 -3.16 mg/100 g of dry matter (dm), and threonine from 2.12 mg/100 g (control) to 2.25 -4.44 mg/100 g of dm. This was in conformity with Shogren et al. [42] who observed that high-lysine content spaghetti can be obtained by adding up to 35% soy flour without an adverse effect on the flavor and texture. Raphia sudanica mesocarp flour is rich in glutamic acid and proline, which are the functional amino acids in dough formation, as they provide sulfhydryl groups for the disulphide bond formation that links these glutenin protein macromolecules. The branched-chain amino acids (BCAAs) leucine, isoleucine and valine are indispensable amino acids. Apart from being building blocks of proteins, they also function as physiological stimulants (especially leucine) for protein synthesis and can promote anabolic effects on protein metabolism by increasing the rate of protein synthesis and decreasing the rate of protein degradation [43]. BCAAs can function as pharmacological nutrients for patients with decompensated liver cirrhosis. However, the effects of BCAAs at the early stages of chronic liver disease are not clear [44]. Consumption of high amounts of BCAAs is usually associated with consumption of food supplements, rather than conventional food, and especially pasta. Nevertheless, the nitrogen balance should also be taken in consideration, at the same level that is usually included in food supplements. Data from previous studies [45] [46] have suggested that oral BCAA supplementation can be useful to improve protein catabolism and lipolysis in cirrhotic patients. Similar findings were reported when Kuwahata et al., [46] studied BCAA attenuation of hepatic apoptosis in rats with chronic liver disease. Therefore, sorghum/raphia sudanica mesocarp/arrowroot pasta might be useful if incorporated into the daily diet for patients with decompensated liver cirrhosis. The sorghum/arrowroot and sorghum/raphia sudanica mesocarp/arrowroot pasta had 3-fold more BCAAs than conventional durum wheat pasta. Also, the sorghum/raphia sudanica mesocarp/arrowroot pasta had leucine/valine/isoleucine in almost the recommended ratio of 2:1:1 [47] [48].

Fatty Acids Composition of Composite Spaghetti
The fatty acid composition of Raphia sudanica mesocarp oil gave the total concentration of saturated fatty acids as 124.49 mg/100 g (49.74%) and that of unsaturated fatty acids as 125.81 mg/100 g (50.26%) with stearic acid (18.77%) being the predominant saturated fatty acid and linoleic acid (30.09%), the predominant unsaturated fatty acid as shown in Table 5. Raphia sudanica mesocarp oil had comparable linoleic (30.85%) and stearic (15.46%) acids content, lower oleic acid content but higher palmitic acid content than African pear oil [49].  lipoprotein cholesterol levels in man. The mesocarp oil showed greater dominance (6) in the number of saturated fatty acids than unsaturated (2) fatty acids. The higher content of both monounsaturated and polyunsaturated (PUFA) fatty acids than saturated fatty acids (SFA) may confer plasma cholesterol-lowering potentials on the composite spaghetti blends. The fact that Raphia sudanica mesocarp oil is rich in oleic acid means that the oil is most probably non-drying oil even though it contain more than 50% unsaturated fatty acids. This maybe so because the participation of monounsaturated oleic acid in the drying of oil is limited as oils with more polyunsaturated fatty acids than monounsaturated acids are more susceptible to oxidation and drying and as a rule, only linoleic, linolenic, ricinoleic and α-eleostearic acids are constituents of drying oils. The rich monounsaturated oleic acid content of Raphia sudanica mesocarp oil may also confer greater oxidative stability than oils containing more polyunsaturated fatty acids. The oil from Raphia sudanica mesocarp flour may make the texture of the spaghetti smoother and silkier. It will also make the dough easily extrude from the pasta machine and enhance the flavour of the spaghetti. High lipid content of pasta containing non-traditional ingredients has been reported to reduce the friction between dough and metal surface inside the extrusion barrel [50]. The use of non-traditional ingredients (with more protein and lipid than semolina) in spaghetti production has been reported to improve its nutritional value and to provide potential health benefits to consumers [51]. The  The increase in saturated fatty acids with sorghum flour replacement was of the order capric < lauric < myristic < arachidonic < stearic < palmitic while for unsaturated fatty acids was oleic < linoleic. The elevation in the total lauric, myristic and palmitic acid contents of the composite spaghetti blends may cause elevations in serum total and LDL cholesterol levels as well as decrease in energy utilization. This however, may be countered by the high levels of stearic, oleic and linoleic acids (with higher cholesterol lowering and energy utilizing ability) content of the composite spaghetti samples. The higher cholesterol lowering and sustained energy utilizing ability of stearic, oleic and linoleic acids may be harnessed in treatment of hypercholesterolemia and obesity in man. Substitution of high monounsaturated fatty acids (MUFA) fats for saturated fatty acids (SFA) containing fats in manufactured foods and margarines have also been shown to have beneficial effects on blood cholesterol and other health related outcomes [52]. The fat content of the composite spaghetti comprised of 6 saturated and 2 unsaturated fatty acids of which palmitic and stearic acids represented 46.89 mg/100 g saturated fatty acids while oleic and linoleic acids represented 81.38 mg/100 g of the unsaturated fatty acids. Epidemiological studies have shown that various fatty acids have different biological consequences when ingested singularly or together. Saturated fatty acids in general, and palmitic acid (C16:0) in particular, are harmful in part because they elevate low density lipoprotein cholesterol and atherosclerosis risk [53].
Kien et al. [54] reported that intake of a diet containing high-palmitic acid levels caused decreased fat oxidation and increased body fat gain (per unit of energy intake), compared with a high oleic acid diet. The high level of fatty acids in the composite spaghetti is an indication that it may be a major source of the fat-soluble vitamins A, D, E and K, and the carotenoids [55]. However, the unsaturated to saturated fatty acid ratio is 0.50:0.49, while PUFA/SFA ratio is 0.38:0.62 but the Recommended ratio is 0.45 [56].
Sang and Kyung [57] reported that capric acid treatment alleviated inflammatory cytokine production and related gene expression, alleviated oxidative stress and increased oxidative stress-related gene expression in cyclophosphamide-treated IPEC-J2 cells. The permeability of FD-4 and expression of ZO-1 and OCLN in cyclophosphamide-treated IPEC-J2 cells were reduced by capric acid. Dietary capric acid reduced TNF-α, IL-6, and MDA levels and increased SOD, GPx, and the expression of genes related to pro-inflammatory, oxidative stress, and intestinal barrier functions in cyclophosphamide-treated miniature pigs. These results revealed that capric acid has protective effects against cyclophosphamide induced small intestinal dysfunction in pigs. The capric acid contents of this study may also confer these health benefits on consumers.
The 11.6 -22.64 mg/100 g stearic acid contents of this study were higher than  [62]. Oleic acid modulates blood pressure, viscosity, transport of cations in erythrocytes [63] and lipid metabolism [64]. It affects numerous enzymatic activities of transport and receptors, as well as desaturation of essential fatty acids [65]. Many studies have shown the influence of the presence of a high level of oleic acid on fatty acid composition of different types of tissues and cells in numerous species [66] and platelets [67].
Arachinic acid (ARA) is an integral constituent of biological cell membrane, conferring it with fluidity and flexibility, so necessary for the function of all cells, especially in nervous system, skeletal muscle, and immune system. Arachinic acid is obtained from food or by desaturation and chain elongation of the plant-rich essential fatty acid, linoleic acid. Free ARA modulates the function of ion channels, several receptors and enzymes, via activation as well as inhibition [68]. ARA is an important component of human milk but is lacking in cow milk and most commercial infant formula in developing countries [69]. Due to its importance in development especially of the central nervous system and retina [70], the Food and Agricultural Organization (FAO)/World Health Organization (WHO) recommended that infant formula, unless specifically added, should be supplemented with ARA [71]. Decreased postnatal ARA blood levels in premature infants were found to be associated with neonatal morbidities, while adding ARA to preterm-infant formulas led to improved visual acuity, visual attention and cognitive development [72] [73]. Table 6 shows mean sensory scores of sorghum/raphia sudanica mesocarp/arrowroot composite spaghetti samples. The acceptability of the composite spaghetti samples decreased with every 5% substitution of sorghum flour with raphia sudanica mesocarp flour. Sorghum/arrowroot spaghetti (control) was the most preferred spaghetti by the panelists for all the sensory attributes assessed.

Conclusion
Utilization of Raphia sudanica mesocarp flour in spaghetti production was feasible. Raphia sudanica mesocarp flour may be used to supplement amino and fatty  acids in spaghetti and to produce a quick cooking pasta product. Its incorporation in spaghetti production elevated the iron, zinc, potassium, calcium and phytochemical contents of the composite blends but decreased their magnesium and sodium contents. Commercial production of Raphia sudanica mesocarp flour is recommended.

Conflicts of Interest
The authors declare no conflicts of interest regarding the publication of this paper.