Article

Nutrients and antinutrients composition of raw, cooked and sun-dried sweet potato leaves

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  • Mwenge Catholic University (MWECAU)
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Abstract

Traditional indigenous vegetables are the most economically efficient source of micronutrients in terms of both land required and production costs per unit. Promotion of production and consumption of such micronutrient-rich foods will improve intakes, the overall diet, and health status. This study aimed to determine nutrient (iron, calcium, vitamin A and ascorbic acid) and anti-nutrient (oxalates and polyphenols) contents in raw, cooked and dried sweet potato leaves Two varieties of sweet potatoes, which were identified as commonly grown for leaves consumption were analyzed at Department of Food Technology, Sokoine University of Agriculture and at the Government Chief Chemist Laboratory Tanzania. The analysis included proximate, nutrient (ascorbic acid, carotenoids, iron and calcium) and anti-nutrient (oxalate and polyphenols) composition. The purple midrib sweet potato leaves were further analyzed for nutrient and anti-nutrient retention after cooking (with and without lemon) and open sun-drying (with and without salting). There was no significant difference (P>0.05) between the two varieties in crude protein, crude lipid and moisture content. The purple midrib sweet potato leaves had significantly (P<0.05) higher ash, crude fibre, carotenoids, calcium and iron contents while the green midrib sweet potato leaves had significantly (P<0.05) higher ascorbic acid content. The polyphenols were about 4 times higher in the purple midrib sweet potato leaves (22.16%) as compared to that of the green ones (5.28%), which had significantly higher oxalate levels (3730 mg/100g). Drying with salt and cooking with lemon reduced polyphenols significantly (p<0.05), with retention of 42% and 56% respectively; while cooking with lemon lowered significantly the oxalate levels. The traditional methods of cooking SPL with addition of lemon is advantageous because it reduces polyphenols while retaining higher levels of minerals, β carotene and vitamin C. Drying with salt results in a nutritionally and organoleptically good product, hence, drying with salt and cooking with addition of lemon is encouraged. Since the sweet potato leaves are harvested more than once before the plant is uprooted, further studies are recommended to assess whether there is variation in nutrient and anti-nutrient contents in consecutive harvests. Key words: Sweet potato leaves, nutrients, antinutrients

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... However, recent works have exposed the vines and leaves, which were regarded as useful only as animal feed [19], to bealso rich and in some instances, richer sources of the same organic food nutrients especially carbohydrates and proteins. The leaves of sweet potato have been found to contain useful minerals like potassium (K), sodium (Na), magnesium (Mg), calcium (Ca), iron (Fe), zink (Zn) and manganese (Mn), etc. Theyas well are fortified with health beneficial phytochemicals including phenolic compounds, flavonoids, etc. which exhibit antioxidant properties [1][2]4,7,[20][21][22][23][24]. In keeping with these discoveries, various workers have published data on the potential of sweet potato as a medicinal plant in the treatment of pathogenic conditions, cancer, ulcer, diabetes, inflammations, etc. [7,[12][13]19,25] cited in [4]. ...
... The lowest protein (4.11 ± 0.04%) and carbohydrate (5.72 ± 0.04%) contents occurred in leaves of AO and RL varieties respectively. The mean protein content range of 4.11% to 6.17% falls within the findings of 3.02 % to 7.38% in sweet potato vines by Gupta et al. [19], in Rajasthan.On the other hand, the range of protein recorded here is much lower than the range of 26.37% to 37.06% reported in Tanzania [20]. The protein of sweet potato leaves, according to Mwanri et al. [20], are rich in the amino acids lysine and tryptophan, which are deficient in grains. ...
... The mean protein content range of 4.11% to 6.17% falls within the findings of 3.02 % to 7.38% in sweet potato vines by Gupta et al. [19], in Rajasthan.On the other hand, the range of protein recorded here is much lower than the range of 26.37% to 37.06% reported in Tanzania [20]. The protein of sweet potato leaves, according to Mwanri et al. [20], are rich in the amino acids lysine and tryptophan, which are deficient in grains. Sweet potato leaves, therefore, can augment the amino acid requirement of people in developing countries whose main diet is on grains and where animal protein is not readily affordable tolow income earners. ...
Article
Aim: To determine the nutrients, minerals and phytochemicals contained in leaves of five sweet potato varieties. Study Design: The study was carried out in the dry season from November 2018 to March 2019, using a randomized complete block design (RCBD).During planting, 10 cm length of each 30 cm long soft wood vine cutting was inserted into the soil and immediately watered. A space of 60cm was left between the plants and there were five vine cuttings planted per ridge. The order of planting the vine cuttings was the same on each replicate ridge. Each treatment had three replications with each replicate having five plants to give a total of75 vine cuttings in all. Leaves of the sweet potato varieties; Agric white (AW), Agric orange flesh (AO), Red skin (RS), Orange flesh (OF) and Red local (RL) were parceled; each variety in a separate parcel, appropriately labelled and sent to the Food Science Laboratory of Kwame Nkrumah University of Science and Technology, Kumasi, Ghana, for analysis. Study Site: The sweet potatoes were cultivated in the experimental field of Ecological Agriculture Department, Bolgatanga Technical Universityin Bolgatanga Municipality of Upper East Region, Ghana. Methodology: Proximate analysis was done and nutrient content expressed in percentages (%). Concentrations of the minerals iron (Fe), potassium (K), calcium (Ca), zinc (Zn), manganese (Mn) and magnesium in milligrams per kilogram (Mg/Kg) were determined. Total phenolic content (TPC) as well as the concentrations of carotenoids and Flavonoids were also estimated and expressed in Mg/Kg. Antioxidant properties of the leaves was determined and reported in mg/Kg. Results: Proximate analysis of the leaves show that all five sweet potato varieties are very nutritious. Leaves of AW variety recorded the highest protein (6.17± 0.43%) and carbohydrates (8.61 ± 0.32%). The content of crude fibre is generally high in leaves of all varieties, ranging from1.42 ± 0.50% in AO to 2.42 ± 0.18% in OF. The proportion of fat in all the varieties is similar, averaging 2,096 ± 0.046%, with the highest of 2.25 ± 0.06% in AO. The two orange flesh varieties, OF and AO, had the highest and higher concentrations of iron (Fe) of 2,020.41 and 467.11 mg/Kg respectively. Magnesium (Mg) is the element that occurred in highest concentration of all the minerals, with an average concentration of 7,991.02 mg/Kg. The OF variety contained the highest concentration of total phenol of 875.00 ± 95.86 mg/Kg. With an average of 4,915.00 ± 166.00 mg/Kg, the concentration of flavonoids in all five varieties in the current study is similar. The concentration of total carotene decreased in the order RL>RS>AW>AO>OF, with the RL variety containing 124.22 ± 10.00 mg/Kg while the OF one possessed 49.39 ± 2.00 mg/Kg. The content pattern of beta carotene was RL> RS> AW> OF> AO, with RL variety containing 4.56 ± .03mg/Kg as AO had 1.57 ± 0.53 mg/Kg. The capacity of phytochemicals in the sweet potato varieties to scavenge and inhibit free radicals as well as reactive oxygen species [using the DPPH (1,1-diphenyl-2-picrylhydrazyl) assay] was highest in the OF variety (51.073%). Conclusion: Leaves of the five sweet potato varieties studied are rich in diverse nutrients and phytochemicals. Therefore, encouraging the growth and consumption of both leaves and root tubers is a cheaper means of reducing malnutrition and enhancing good public health. It is therefore, essential for more investigations to establish the nutrient content and nutrachemical capabilities of both roots and leaves of the different varieties of sweet potato in the different environments so as to equip the general public with appropriate information to guide dieting choices.
... The levels of vitamin C in raw roots in our study were higher than a range of 13.7-23.5 mg/100 g reported in Slovenia (Sinkovič et al., 2017) but comparable to values reported in Tanzania of 273-303 mg/100 g for sweetpotato leaves (Mwanri et al., 2011).Vitamin C is highly susceptible to oxidation more so in aqueous solutions, oxidation being fueled by the presence of oxygen, metal ions such as iron and copper and high temperature (Akah & Onweluzo, 2014;Lee & Kader, 2000). Traditionally, leaves are boiled in water for more than 10 min. ...
... On the other hand, dehydration led to 80%-90% loss of the vitamin. These results were in agreement with 15% retention reported by other researchers (Mwanri et al., 2011). ...
... Lower levels of the vitamin in crisps can be attributed to higher surface area to volume ratio that exposed the entire matrix to high frying temperature. Our results to some degree agree with previous studies reporting higher losses of vitamin C in boiled roots (72.37%) and fries (60.9%) (Ikanone & Oyekan, 2014) and 40% loss of vitamin C in boiled roots (Mwanri et al., 2011). However, it was noted that high vitamin C retention in roots (>90%) can be achieved depending on exposure to heat and leaching water (FAO, 2016) as root matrix inhibits excessive loss of the vitamin. ...
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Phytochemicals enhance human health by acting antagonistically on incidences of cancer and other chronic diseases. They are considered indispensable in a variety of nutraceutical, pharmaceuticals, and medicinal and cosmetic applications. This study evaluated the effects of common processing methods on inherent phytochemical content in the roots and leaves of orange‐fleshed sweetpotato (OFSP) varieties called Kabode and SPK031. Yellosp and Whitesp, which are local sweetpotato varieties, were also included as check for roots and leaves, respectively. The sweetpotato products prepared for phytochemical analysis were boiling roots and leaves, frying chips and crisps, baking bread (for roots only), and fermenting and dehydrating leaves. Phytochemicals that were assessed included vitamin C, total phenolics and flavonoids, tannins, phytates, and soluble oxalates. Results indicated that retention of vitamin C was highest in boiled roots (85%–95%), followed by fries (71%–94%) and crisps (44%–76%), whereas the least retention was in bread (4%–11%) and leaves (0%–27%). Total phenolics, flavonoids, and antioxidant activity in leaves significantly (p < .05) varied with the type of processing. Higher retention of these phytochemicals was observed in processed roots but was lowest in bread. Boiling retained more than 100% of all carotenoids, while fermenting and drying the leaves retained 58–62 and 22%–48%, respectively. Frying retained more than 100% of the β‐carotene in the roots, while boiling retained 96%–100%. All processing methods significantly (p < .05) reduced antinutrients in leaves and roots. Fermentation of leaves had higher reduction of oxalates, tannins, and phytates, while boiling had the least effect. It is concluded that traditional boiling enhances phytochemical retention in roots but degrades most of them in leaves.
... Lipid content of the raw leaf was 0.51 ± 0.007%, and this was within the range for leafy vegetables reported previously [16,18,19] but was below the range for some leafy vegetables reported by others [17,[20][21][22]. The leaf extracts were low in lipid content and significantly (p < 0.05) lower than the fat content of the raw leaf (RL). ...
... There were some significant variations in the level of protein in the leaf products as their protein content ranged from 0.94 to 2.60%, with the raw leaf (RL) having crude protein content of 1.80 ± 0.014%. These protein content values were far below the range obtained from other leafy vegetables as reported by other research groups [17,22,24] but were within the range obtained from Kenaf and Corchorus leaves [19], H. sabdariffa [18] and Telfaria accidentalis [16]. Extraction significantly (p < 0.05) reduced the protein content of the leaf products. ...
... Ash content of the processed products ranged from 2.48 to 11.81% with the raw leaf (RL) having a value of 2.48 ± 0.035%. The ash contents of the raw leaf (RL) was higher than the ash content of some leafy vegetables reported by Mepba et al. [16], Gupta and Prakash [25], Shokunbi et al. [21] but were within the range of some other leafy vegetables reported by Awogbemi and Ogunleye [18], Nkafamiya et al. [17] and were lower than those reported by Akubugwo et al. [26], Lewu et al. [27], and Mwanri et al. [22]. Extraction caused a decrease in the ash content of the leaf. ...
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Leaves of Hibiscus rosa-sinensis are processed using different methods depending on the intended application. Using three different processing methods, we investigated the effects of processing on the proximate constitution of the leaf. Result demonstrated that the fresh raw leaf had moisture content of 82.30 ± 0.42%, which were significantly (p<0.05) reduced by drying but not extraction and blanching. The protein content of the raw leaf was low (1.80 ± 0.10%). Extraction and blanching reduced the protein content, whereas drying increased the protein content significantly (p < 0.05) for raw dried leaf powder and blanched leaf products. The raw leaf contained vitamins A, B2, C and E, which were significantly reduced by extraction and blanching, but were concentrated by drying. Anti-nutrient contents of the raw leaf were low and were reduced to negligible levels by the processing techniques employed. Comparing the nutrient and chemical constituents with recommended dietary allowance (RDA) values; we found that the leaves contain an appreciable amount of nutrients, minerals, vitamins, proteins and phytochemicals and low degree of toxicants. These findings suggested that the treatment method employed in processing this leaf affected the proximate composition, and this should be considered in utilization of this leaf (and other leaves) product in various food and pharmaceutical formulations
... The total oxalate contents reported in this study for Amaranthus dubius, Colocasia esculenta and Ipomoea batatas leaves were within the range of earlier reports (Mizray et al. 2001;Lumu and Katongole 2011;Mwanri et al. 2011). However, the contents reported for Manihot esculenta and Brassica oleracea leaves were higher by 58% and 57%, respectively, than those reported by Wobeto et al. (2007) and Edorgan and Onar (2012). ...
... The soluble proportion of oxalates in Colocasia esculenta leaves has been reported to be 74% of the total oxalate (Oscarsson and Savage 2007). On the other hand, Amaranthus leaves have been reported to contain less than 10% soluble oxalates (Radek and Savage 2008;Onyango et al. 2012), while Brassica oleracea and Ipomoea batatas leaves have been reported to contain about 50% soluble oxalates (Mwanri et al. 2011;Kasimala et al. 2018). The higher the percentage of soluble oxalates in plant leaves, the higher the reduction in total oxalate content of the plant leaves. ...
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Plant leaves are increasingly being integrated into poultry production systems in developing countries because leaves can reduce the proportion of the expensive conventional protein ingredients. Plant leaves are also good sources of minerals and carotenoid pigments for colouring broiler skins and egg yolks. In Uganda, leaves from plants including Colocasia esculenta (cocoyam), Manihot esculenta (cassava), Amaranthus dubius (amaranthus), Brassica oleracea (sukuma wiki) and Ipomoea batatas (sweet potato) are largely fed to quails in their fresh forms. However, minerals, particularly calcium and phosphorus of fresh plant leaves are biologically less available for absorption because of the presence of oxalates and phytates, which bind these minerals. Therefore, in this study, the effect of sun-drying on total oxalate and phytate contents of plant leaves commonly used in quail feeding in Uganda was determined. Samples of five most commonly used plant leaves in quail feeding were collected during the dry and wet seasons, and analysed for total oxalate and phytate compositions after sun-drying or oven-drying. Total oxalate and phytate contents were significantly lower (P ≤ 0.05) in the sun-dried samples compared with the oven-dried samples. Overall mean oxalate contents were 71, 67, 64, 62, and 58% lower for sun-dried Colocasia esculenta, Manihot esculenta, Ipomoea batatas, Brassica oleracea and Amaranthus dubius leaves, respectively. For total phytate, the contents were 66, 19 and 9 % lower for sun-dried Colocasia esculenta, Amaranthus dubius and Amaranthus dubius leaves, respectively. Total oxalate and phytate contents were highest in Brassica oleracea, followed by Colocasia esculenta leaves, and lowest in Amaranthus dubius and Ipomoea batatas leaves. The contents ranged from 2.3-5.4 g/100g DM (total oxalates), and 12-68 mg/100g DM (total phytates). It was concluded that oxalate and phytate contents varied with plant type and that sun-drying is an effective processing technique for reducing total oxalates and phytates in plant leaves used to feed quails in Uganda.
... Variation was observed in oxalate content across the cultivars. Oxalate content was much lower than reported in other vegetables like sweet potato leaves and amaranths consumed in Tanzania, Kenya and in Nigeria (Musa and Ogbadoyi, 2014;Mwanri et al., 2011;Mziray et al., 2001). Studies show that chemical composition of plants is affected among other things the variety and even the cultivar (Singh et al., 2001). ...
... A study by Virginia et al. (2012) on effects of cooking and processing on oxalate content in green leafy vegetables and pulses revealed that blanching, pressure cooking for 10 min and open pan cooking of green leafy vegetables reduced their oxalate concentration from 88.8 mg/100 g fresh samples to 48.4, 57.2 and 60.13 mg/100 g, respectively. Other studies reported reduction of oxalates in boiling and drying of vegetables (Essack et al., 2017;Ilelaboye et al., 2013;Mwanri et al., 2011); which means the amount of oxalate present in studied vegetables may not be harmful for human consumption since the contents were relatively low and these vegetables are usually boiled before consumption. ...
... Sweet potato flour and starch may also be processed [1]. Utilizing new cultivars of OFSP that have the nutritious benefits and also containing pigments including; flavones, phenolic acids, and anthocyanins, is one way to expand the market opportunities for the sweet potato industry [2,3,4]. The development of new products from sweet potato with functional attributes could further improve its consumption among families while improving on the shelf life of the product [2,3,4]. ...
... Utilizing new cultivars of OFSP that have the nutritious benefits and also containing pigments including; flavones, phenolic acids, and anthocyanins, is one way to expand the market opportunities for the sweet potato industry [2,3,4]. The development of new products from sweet potato with functional attributes could further improve its consumption among families while improving on the shelf life of the product [2,3,4]. Some varieties of sweet potatoes contain coloured pigments such as βcarotene, anthocyanin and phenolic compounds. ...
... Sweet potato flour and starch may also be processed [1]. Utilizing new cultivars of OFSP that have the nutritious benefits and also containing pigments including; flavones, phenolic acids, and anthocyanins, is one way to expand the market opportunities for the sweet potato industry [2, 3, 4]. The development of new products from sweet potato with functional attributes could further improve its consumption among families while improving on the shelf life of the product [2, 3, 4]. ...
... Utilizing new cultivars of OFSP that have the nutritious benefits and also containing pigments including; flavones, phenolic acids, and anthocyanins, is one way to expand the market opportunities for the sweet potato industry [2, 3, 4]. The development of new products from sweet potato with functional attributes could further improve its consumption among families while improving on the shelf life of the product [2, 3, 4]. Some varieties of sweet potatoes contain coloured pigments such as βcarotene , anthocyanin and phenolic compounds. ...
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Abstract: Lacto-products processed by lactic acid fermentatio n are known to have nutraceutical attributes and cr eate variety in the beverage composition. Due to their h igh nutritive value, they are beneficial to human h ealth when consumed regularly. In this study orange fleshed potato vari eties (Zapallo, Nyathiodiewo and SPK004/06) were fe rmented with Lactobacillus plantarum MTCC 1407 at 25 ± 2°C for 48 h and kept for 28 day s to make lacto-pickles. An optimization of process conditions was done by varying brine levels with fermentation time. The fermented products wer e subjected to panelist evaluation for flavour profiling. The prod uct sensory scores were (1.5-2.5) on a 5 point hedo nic scale ranging from dislike slightly to like much. The product with bri ne levels at 4 and 6% were found to be most preferr ed. The findings from this study indicate the acceptability of the develo ped lacto-pickles and suggest that the development of new products from sweet potato with functional attributes could impro ve its consumption among families while enhancing t he shelf life of the product. It was concluded that the β-carotene rich, sweet potato lacto-pickle is a novel product which could find wide acceptance with good prospects for commercializatio n in small-scale industries
... Prior research on nutrition profiling of SPL (Antia., 2006;Ishida et al., 2000;Mwanri., 2011) provided the foundation for this current work which sought to provide scientific data on the commonly consumed SPL varieties in Zambia. Nutritional value of agricultural products can vary significantly with geographical location, agricultural practices and genetics (Amarteifio et al., 2010). ...
Article
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In Zambia, sweet potato (Ipomoea batatas) leaves (SPL) provide an inexpensive and effective source of nutrients and phytochemicals with several health benefits that include improved eye health and prevention of cardiovascular diseases. This study was conducted to determine the nutrient content of two SPL varieties, called purple and green SPL, commonly sold at the Soweto market, the largest vegetable trading market in Lusaka, Zambia. The proximate, vitamin (β-carotene and vitamin C) and mineral (calcium - Ca, iron - Fe, zinc - Zn, potassium - K and phosphorous - P) composition of the raw as well as the steamed (for 10 and 15 minutes) SPL were tested. The results showed no significant differences (p<0.05) in the proximate composition of both raw green and purple SPL. Results from the raw samples showed that the green SPL had significantly (p<0.05) higher levels of P (176.1 ± 7.0 mg/100g), while the purple SPL had higher levels of vitamin C (17.7 ± 0.9 mg/100g). When steamed for 10 minutes, the P (150.6 ± 24.4 mg/100g) and vitamin C (11.8 ± 1.1 mg/100g) content of the green SPL significantly reduced, while the crude protein (23.5 ± 1.5 g/100g), Fe (13.7 ± 2.2 mg/100g), ash (17.9 ± 2.8 g/100g), Zn (1.3 ± 0.1 mg/100g) and K (4.2 ± 0.2 mg/100g) content of the purple SPL significantly reduced when steamed for 15 minutes (p<0.05). The mean β-carotene content of the green SPL increased from 476 to 490 μg/100g upon steaming for 15 minutes, suggesting the release of carotenoids from their cellular matrix upon cooking. Overall, the retention of nutrients in the green SPL was higher than that observed in the purple SPL when steamed. Considering the substantial increase in β-carotene upon steaming, further research should focus on the effects of other domestic cooking methods and nutrient bioavailability. If recommended temperature-time combinations are used for cooking, with sufficient amounts consequently being consumed, SPL have the potential to improve the nutritional status of the Zambian people.
... Sweet potato leaves are recognized to be rich in essential amino acids, such as lysine and tryptophan which are always limited in cereals. Hence, sweet potato can easily replace grain-based diets in livestock nutrition (Mwanri et al., 2011;Oloo et al., 2014). However, the potential benefits of sweet potato are marginalized and underutilized despite their useful potential, which is well recognized and exploited elsewhere. ...
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The nutritive value and potential use of two varieties of sweet potato (Ipomoea batatas) (LAM.) composite meal for growing rabbits was studied by comparing seven diets containing an increasing incorporation rate of Composite Sweet Potato Meal (CSPM) in replacement for maize. The composite sweet potato meal contained 65 % of whole root tubers and 35 % of the leaves and vines. The rabbits were randomly allocated into seven treatments. The two varieties of sweet potato i.e CIP440293 (Orange-Flesh) CSPM and TIS87/0087 (White-Flesh) CSPM replaced maize at graded levels 25, 50, 75 % respectively. The seven treatments are: T1 − 0 % Control, T2 − 25 % Orange Flesh, T3 − 50 % Orange Flesh, T4 − 75 % Orange Flesh, T5 − 25 % White Flesh Sweet potato, T6 − 50 % White Flesh Sweet potato and T7 − 75 % White Flesh Sweet potato. The treatments were performed in four replicates, each in a Completely Randomized Design (CRD) experiment. The diets contained 10.6 − 12.6 % of crude fibre, 16.4 − 17.6 % of crude protein and 10,9275 − 11,6728 MJ.kg-1 of metabolizable energy ad libitum. Eighty-four rabbit does, at twelve rabbits per treatments, were fed the seven diets from weaning (35 days, mean weight: 570.76 ± 42.09 g) to 98 d of age. The faecal digestibility of the diets was measured between 92 and 97 days of age in 6 rabbits per treatment. CSPM can be considered high-fibre roughage, as it contained 42.45 − 54.30 % of NDF (38.30 − 40.35 % of ADF and 13.30 − 20.40 % ADL) and 9.80 − 17.45 % of CP. The crude fibre digestibility was reduced with CSPM incorporation. Dietary incorporation of CSPM impaired the rabbit growth (18.08 vs. 14.66 g.day-1 during the period 77 − 98 days without CSPM). However, feed conversion was undermining with the high incorporation rate in feed. The dressing-out percentage of rabbits fed on diets containing the CSPM were comparable to the dressing-out percentage of rabbit fed the control diet. Health status or main slaughter traits were not affected by CSPM incorporation rate. Thus, CSPM had a comparable nutritive value for growing rabbits and it can successfully serve as a high-fibre feedstuff through its potential to supply low digested fibres (cellulose) and lignin. The two composite sweet potato meals could be considered as a high fibre source with a considerable high crude protein for the growing rabbits. The comparable dietary potential of the composites makes it an excellent replacement for maize, which is the conventional feed stuff, especially for hind gut fermenters like rabbits.
... Boiling of Bambara groundnut seeds for about 1 h greatly decreased the amount of raffinose and also enhanced protein digestibility of seeds was obtained [52]. The cooking of a mixture of sweet potato leaves and lemon together decreased the amount of both phenolic (56%) as well as oxalate components [53]. ...
Article
Plant-based food products are gaining more importance and they play an important role in maintaining sustainable, low-meat, and healthy diets. Plant-based food products, specifically legumes and cereals, are important staple foods in developing countries. However, it is important to know whether these plant-based systems are capable of delivering the minerals and is it beneficial to motivate consumption to decrease the manifestation of mineral deficiencies. Plant-based foods apart from containing a large number of macronutrients and micronutrients they also possess various anti-nutritional factors. Some of the major anti-nutritional components present in plants are saponins, tannins, phytic acid, lectins, protease inhibitors, and amylase inhibitors. Such kind interactions with minerals interfere in bioavailability from plant-based foods throughout the course of human digestion and lead to micronutrient malnutrition and mineral deficiencies. Lacto-fermentation is commonly used to disrupt such interactions and make nutrients and phytochemicals free and accessible to the consumers. The purpose of this review was to provide information about the different types of antinutrients present in plant sources, their possible effects on the human body, and the benefits of lacto-fermentation over other conventional food processing approaches such as soaking, germination, and heating in the reduction of antinutrients.
... Traditional indigenous vegetables are the most economically efficient source of micronutrients in terms of both land required and production costs per unit. Promotion of production and consumption of such micronutrient (iron, calcium, vitamin A and ascorbic acid) rich foods will help to overcome the problem (Mwanri et al., 2011). Calcium, Cu, Fe, Mg, Mn, P, K, Na, Zn are present in most of the vegetable (Emsley, 2001). ...
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A study was conducted on salinity tolerance of sweet gourd in selected tidal areas of Barguna and Patuakhali district during July, 2013 to June, 2014. Vegetable and soils of different locations were taken under investigation. On the basis of soil salinity, Sonakata, Taltoli, Barguna was selected as saline area (EC value 7.9 dS m-1) and Kadomtola, Dumki; Patuakhali was selected as non-saline area (EC value 1.19 dS m-1). The soil and vegetable were analyzed for Phosphorus (P), potassium (K), magnesium (Mg), calcium (Ca), Sulphur (S), Soil pH and EC. In saline area comparatively lower amounts of Phosphorus (P), potassium (K), magnesium (Mg), calcium (Ca), Sulphur (S) were found in sweet gourd and sweet gourd leaf than that of non-saline area. Accumulation of different mineral constituents in sweat gourd was remarkably affected by salinity. The uptake of K, S and P in sweet gourd was increased with decrease of soil EC level. The discussed vegetable can grow in saline area with sufficient mineral composition though the amounts of these minerals were found lower than vegetable grown in non-saline area. Considering the findings achieved sweet gourd can tolerate moderate salinity (soil EC value up to7.9 dSm-1) and might be recommended to grow commercially in the study area for nutritional security.
... Sweet potato leaves are recognized to be rich in essential amino acids, such as lysine and tryptophan which are always limited in cereals. Hence, sweet potato can easily replace cereal based diets in livestock nutrition (Mwanri et al., 2011;Oloo et al., 2014). However, sweet potato are marginalized and are underutilized despite their useful potential which is well recognized and exploited elsewhere (Anyaegbunam et al., 2016). ...
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Eighty-four does of mixed breeds aged 6-8 weeks, weighing 550-600g were used to determine the effect of feeding two varieties of composite sweet potato (Ipomoea batatas) root meal (CSPM) on the haematological and serum biochemical indices of rabbits. The rabbits were randomly allocated into seven treatments. T1 was the control while T2, T3, T4, contained 25, 50 and 75 % of maize replaced with CIP440293 CSPM and T5, T6 and T7 contained TIS87/0087 CSPM replaced with 25, 50 and 75 % of maize. The treatments had four replicates each in a Completely Randomized Design (CRD) experiment. The diets contained 10.6-12.6 % crude fibre, 16.4-17.6 % crude protein and 2610-2788 Kcal/Kg metabolizable energy. Parameters measured were growth, haematological and serum biochemical index of the rabbit. The result showed that there were significant (P<0.05) differences on the final weight gain, daily feed intake, daily weight gain, feed cost and survival ability of the rabbits. The FCR was not significantly (P>0.05) different across the dietary treatments. At the end of nine weeks of feeding trial, blood samples were collected from three rabbits per treatment. The results indicate that the dietary treatments had significant (P<0.05) influence on the concentrations of white blood cells and eosinophils. However, there were no significant influence of the diets on other haematological parameters. Total protein, urea, globulin and creatinine were also not affected (P>0.05) by the treatment diets but albumin, cholesterol, glucose, aspartate transaminase (AST), alanine transaminase (ALT) and alkaline phosphatase (ALP) were influenced by the different dietary treatments. These results show that CSPM of two varieties can be included up 50 % in growing rabbit diets without adverse effect on haematology and serum indices of rabbits.
... mg/100 g reported by Alam et al. [35]. e β-carotene content in the leaves were, however, lower compared to an average of 53.32 mg/100 g for Tanzanian sweet potato varieties [36]. e lutein content was higher compared to the range of 19.01-28.85 ...
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This study reports the inherent phytochemical contents in leaves and roots of nine sweet potato varieties from Kenya. Results indicated that vitamin C content varied significantly ( P<0.05 ) among the sweet potato varieties regardless of the plant part, leaves having significantly ( P<0.05 ) higher levels than in the roots. Total flavonoids and phenolic compounds differed significantly ( P<0.05 ) among varieties, higher values were found in leaves than in roots. Flavonoid contents in roots ranged from below detectable limits (Whitesp) to 25.8 mg CE/100 g (SPK031), while in leaves it ranged from 4097 to 7316 mg CE/100 g in SPK4 and Kenspot 5, respectively. Phenolic content was below detectable limits in the roots of whitesp but it was in substantial amounts in orange fleshed varieties. The β -carotene content was significantly ( P<0.05 ) higher in leaves (16.43–34.47 mg/100 g dry weight) than in roots (not detected—11.1 mg/100 g dry weight). Total and phytic phosphorus were directly correlated with phytate contents in leaves and the roots. Tannins and soluble oxalates varied significantly ( P<0.05 ) with variety and plant part being higher in leaves. The current information is important for ration formulations and dietary recommendations utilizing sweet potato leaves and roots. Future studies on effects of processing methods on these phytochemicals are recommended.
... Their leaves are high in essential amino acids, lysine and tryptophan. These two amino acids are always limited in cereals thus, the sweet potato's leaves can easily complement cereal based diets in the region (Mwanri, Kogi-Makau, & Laswai, 2011). Some varieties of sweet potatoes contain coloured pigments such as β-carotene, anthocyanin and phenolic compounds. ...
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This study aimed to establish the effects of lactic fermentation on the levels of β-carotene in selected orange fleshed sweet potato (OFSP) varieties from Kenya. Furthermore,it sought to demonstrate fermentation as a potential process for making new products from sweet potato with enhanced nutraceutical attributes. The varieties (Zapallo, Nyathiodiewo and SPK004/06) were fermented with Lactobacillus plantarum MTCC 1407 at 25 ± 2°C for 48 h and kept for 28 days to make lacto-pickles. During fermentation both analytical [pH, titratable acidity (TA), lactic acid (LA), starch, total sugar, reducing sugar (g/kg roots), texture (N/m2), β-carotene (mg/kg roots)] and sensory (texture, taste, flavour and after taste) attributes of sweet potato lacto-juice were evaluated. Process conditions were optimized by varying brine levels, with fermentation time. A UV-visible spectrophotometer was used to identify and quantify β-carotene. Any significant variations (p < 0.05) in analytical attributes between the fermented and unfermented samples (pH, LA, TA and β-carotene concentration) of lacto-pickles, prepared from the potato roots, were assessed. The study reported a final composition of 156.49mg/kg, 0.53mg/kg, 0.3N/m2, 1.3g/kg, 5.86g/kg, 0.5g/kg and 5.86g/kg for β-carotene, Ascorbic acid, texture; Starch, total sugars, LA and TA respectively, and a pH of 3.27. The fermented products were subjected to flavour profiling by a panel. The product sensory scores were 1.5 to 2.5 on a 5 point hedonic scale, ranging from dislike slightly to like much. The products with brine levels at 4 and 6% were most preferred. The retention of β-carotene was 93.97%. This demonstrated lactic acid fermentation as a better method for processing OFSP as the main nutritional attributes are retained. The final product was resistant to spoilage microorganisms after 28 days of fermentation. Further preservation could be obtained by addition of sodium metabisulphite. In conclusion, Lactic acid fermentation using L. plantarum is a novel method of producing Lacto pickles from Zapallo OFSP, with 93.97% β-carotene retention and adequate shelf life.
... Sweet potatoes are not only used as food but also as industrial raw materials and animal feed [1] [2]. Sweet potatoes also contain beta carotene, anthocyanin, phenolic compounds, essential amino acids such as lysine and tryptophan [3] [4]. Potential of sweet potato as a functional food continues to be developed to support food diversification programs. ...
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The study aimed to evaluate the anatomical characteristics of six sweet potato varieties ( Ipomoea batatas L.) after induction of organic fertilizer. Research used Completely Randomized Block Design with 3 replications. Five sweet potato varieties (J) were used i,e: Antin 3 (J1), Jago (J2), Cilembu (J3), Shi Royutaka (J4), Local Purple (J5) and Local White (J6). Petroganic Organic Fertilizers were applied 20 tons/ha, three weeks before sweet potato cuttings were planted. Observation of anatomical characteristics include: stomata density, length and width opened stomatal pores, mesophyll thickness, diameter of the petiole cortex. All characteristics were observed 60 days after planting (HST) using a microscope with a camera Optilab 2.2 and image capture with the Image Raster 3.0 program. Anatomical characters of sweet potatoes showed stomata density J1, J2, J3, J4, J5 and J6 respectively 8.56; 6.11; 5.11; 6.33; 8.56 and 9.11 in 75796.36 μm. The length of opened stomata pores were 26.99 μm, 32.08 μm, 28.96 μm, 38.72 μm, 39.52 μm and 35.86 μm. The width of opened stomata pores were 7.95 μm, 5.11 μm, 4.67 μm, 5.04 μm, 9.28 μm and 6.98 μm. The mesophyll thickness were 364,986 μm, 280,703 μm, 389,743 μm, 245,749 μm, 261,439 μm and 434,913 μm. The diameter of the petiole cortex were 454,030 μm, 373,453 μm, 456,439 μm, 373,001 μm, 275,647 μm and 318,785 μm. Five sweet potato varieties differ in anatomical characters.
... Raw storage root comprises of starch 20.12 g 100 g -1 , fiber 3 g 100 g -1 , protein 1.57 g 100 g -1 , and many essential minerals such as calcium, iron, magnesium, potassium, sodium, and phosphorus [USDA 2010]. It also provides a good amount of vitamin C (2.40 mg 100 g -1 ) and ß-carotene (8.512 mg 100 g -1 ), a precursor of vitamin A. The young leaves of sweet potato are a rich source of minerals and proteins and used as a vegetable in Africa as well as in East Asia [Mwanri et al. 2011]. Sweet potato has a perennial growth habit, however, it is commonly cultivated as an annual [Onwueme andCharles 1994, Norman et al. 1995]. ...
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Sweet potato (Ipomoea batatas (L.) Lam) is an important crop due to its cultivation as staple food for millions of small farmers as well as for poor people in Latin America, Asia, Africa and in many other parts of the world. This tuberous crop is susceptible to drought stress especially during the period of crop establishment as well as vine development and tuber initiation. Yield of the crop vary widely among farmers due to improper planting systems. This current study was aimed to investigate the influence of various irrigation intervals and planting systems on vegetative growth, storage root yield and quality of sweet potato (Ipomoea batatas (L.) Lam) cv. ‘White star’ under field conditions. Three irrigation intervals (7, 14 and 21 days for summer crop, and 14, 28 and 42 days for winter crop) and two planting systems (bed planting and ridge planting) were adopted in this study. Vine length, number of branches and average leaf area significantly reduced as the irrigation interval was increased. Ridge planting produced longer vines with greater leaf area in winter crop as compared to bed planting. Yield parameters (storage root length, storage root diameter, number and fresh weight of marketable roots per plant) were directly linked with vegetative growth especially in summer crop. Under water stress conditions, as vegetative growth decreased storage root yield was also reduced. However, yield attributes were not affected by the planting systems. Vitamin C content decreased with water stress, whereas total soluble solids (TSS) and leaf proline content significantly increased with water stress in summer crop. Ridge planting also resulted in increased leaf proline content in summer crop. It is concluded that for attaining good vegetative growth and storage root yield, sweet potato should be irrigated at an interval of 7 days during summer and 14 days during winter crop and planted on ridges.
... Sweet potato's leaves are recognized to be rich in essential amino acids, such as lysine and tryptophan which are always limited in cereals. Hence, sweet potato can easily complement cereal based diets in the region (Mwanri et al., 2011;Oloo et al., 2014). Moreover, sweet potatoes have high technological potential and it is reported that it can be used for various products, such as drinks (wine, liquor, vinegar), sugar production, biscuits, flour, pasta, alcohol, etc. (Ellong et al., 2014). ...
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Sweet potato is one of the most important food security promoted root crops in the world, especially in sub-Saharan Africa. Unfortunately, the crop is still neglected and underutilized in Benin Republic. To establish baseline data for its better utilization for upgrading its value chain, 10 selected local varieties (01 cream, 02 white, 03 yellow, and 04 orange flesh-colored) were compared for their macro-nutritional composition assessed using standard Association of Official Analytical Chemists (AOAC) procedures and spectrophotometry methods. The results indicate that sweet potato dry matter, protein, fiber, and ash content ranged from 46.11 to 25.9%, 4.09 to 1.97%, 1.81 to 3.00%, and 4.70 to 2.56%, respectively and orange flesh cultivars were found very rich. Pearson correlation analysis of variables revealed that dry mater content is positively correlated with carbohydrate and energy values, but negatively correlated with ash and fiber content, while starch content is strongly correlated with fiber content. Principal component analysis allowed us to classify the sweet potato varieties into 03 varietal groups among which Group 2 (05 varieties) exhibited rich fiber, ash, and protein contents and may be recommended for infant foods formulations. These results constitute important orientation for sweet potato processing chain organization in Benin and for the establishment of future nutrition and breeding programme. Key words: Benin, sweet potato, Ipomoea batatas, nutritional composition, orange flesh cultivar, value chain.
... The differences in the extent of losses especially for the steam blanched vegetables could be attributed to the factors as highlighted by Gupta et al. (2008) who reported that ascorbic acid content of all greens blanched at 80°C showed a reduction but the extent of loss varied between the vegetables and further reported that the differential loss of ascorbic acid in the leafy vegetables could be attributed to different vulnerabilities due to surface area, mechanical damage, initial ascorbic acid content and enzymatic activities. In all the blanching treatments with addition of lemon juice, it was observed that vitamin C was well retained as compared to the untreated samples and similar findings were reported by other authors who concluded that the traditional methods of cooking sweet potato leaves with addition of lemon is advantageous because it reduces polyphenols while retaining higher levels of minerals, β-carotene and vitamin C (Laswai et al., 2011). Similarly, the trend in our findings agrees with what was reported by Sobowale et al. (2010) who reported that among the treatments for leafy vegetables consumed in Nigeria, cooking accounted for 64.3-67.5% loss of vitamin C while blanching and sun drying accounted for 44.8-47.1 and 36.8-39.6%, ...
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Vitamin C is very important for human nutrition and any method that reduces its degradation in foods like vegetables needs to be advocated and utilized. In this current study, the effect of using lemon juice and sun drying on vitamin C retention of steam and water blanched Amaranthus hybridus, Bidens pilosa and Cleome gynandra indigenous vegetables stored for a period of six weeks was investigated. Results showed that the amount of vitamin C retained in lemon juice treated samples was higher than in untreated samples and steam blanching was found to be better in retaining vitamin C than water blanching. The mean vitamin C retention percentages soon after blanching were 80% and 40% respectively for the lemon juice steam and water blanched vegetables in all the vegetables while for control steam blanched vegetables, vitamin C retention ranged from 60-67.8% as compared to a mean retention of 20% for the control water blanched vegetables. Furthermore, results showed that when vitamin C retention after six weeks storage period was compared for each individual indigenous vegetable, the values were higher in lemon juice treated blanched vegetables regardless of blanching type compared to the control samples. The use of lemon juice in vegetable preservation is strongly encouraged.
... Götz and colleagues suggested that high levels of b-carotene in leaves could be helpful for sweetpotato to resist UV damages (Götz et al., 1999). Our study suggests that the leaves of sweetpotato might possess a mechanism of retaining/ storing b-carotene, and hence should be an alternative food source for this vital precursor for vitamin A (Mwanri et al., 2011). ...
... Their leaves are high in essential amino acids, lysine and tryptophan. These two amino acids are always limited in cereals thus, the sweet potato's leaves can easily complement cereal based diets in the region (Mwanri, Kogi-Makau, & Laswai, 2011). Some varieties of sweet potatoes contain coloured pigments such as β-carotene, anthocyanin and phenolic compounds. ...
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Authors who publish in the International Journal of Food Studies agree to the following terms:  Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.  Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.  Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work. Abstract This study aimed to establish the effects of lactic fermentation on the levels of β-carotene in selected orange fleshed sweet potato (OFSP) varieties from Kenya. Furthermore,it sought to demonstrate fermentation as a potential process for making new products from sweet potato with enhanced nu-traceutical attributes. The varieties (Zapallo, Nyathiodiewo and SPK004/06) were fermented with Lactobacillus plantarum MTCC 1407 at 25 ± 2ºC for 48 h and kept for 28 days to make lacto-pickles. During fermentation both analytical (pH, titratable acidity (TA), lactic acid (LA), starch, total sugar, reducing sugar (g/kg roots), texture (N/m 2), β-carotene (mg/kg roots)) and sensory (texture, taste, flavour and after taste) attributes of sweet potato lacto-juice were evaluated. Process conditions were optimized by varying brine levels, with fermentation time. A UV-visible spectrophotometer was used to identify and quantify β-carotene. Any significant variations (p < 0.05) in analytical attributes between the fermented and unfermented samples (pH, LA, TA and β-carotene concentration) of lacto-pickles, prepared from the potato roots, were assessed. The study reported a final composition of 156.49mg/kg, 0.53mg/kg, 0.3N/m 2 , 1.3g/kg, 5.86g/kg, 0.5g/kg and 5.86g/kg for β-carotene, Ascorbic acid, texture; Starch, total sugars, LA and TA respectively, and a pH of 3.27. The fermented products were subjected to flavour profiling by a panel. The product sensory scores were 1.5 to 2.5 on a 5 point hedonic scale, ranging from dislike slightly to like much. The products with brine levels at 4 and 6% were most preferred. The retention of β-carotene was 93.97%. This demonstrated lactic acid fermentation as a better method for processing OFSP as the main nutritional attributes are retained. The final product was resistant to spoilage microorganisms after 28 days of fermentation. Further preservation could be obtained by addition of sodium metabisulphite. In conclusion, Lactic acid fermentation using L. plantarum is a novel method of producing Lacto pickles from Zapallo OFSP, with 93.97% β-carotene retention and adequate shelf life.
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Sweet potatoes (SPs) are a versatile tuberous crop used as subsistence and cash crop in raw and processed forms. The major issue with SPs is post-harvest losses, which result in noticeable quality decline because of inappropriate handling, storage, delayed transit, and sales, as well as microbiological and enzymatic activity. Drying is an excellent strategy for managing short postharvest storage life, preserving nutrients, and maximizing long-term benefits. However, several parameters must be considered before drying SPs, such as relative humidity, temperature, drying duration, size, and shape. The current review looks at the factors influencing SPs' moisture loss, drying kinetics, diverse drying methods, pretreatments, operating conditions, and their efficacy in improving the drying process, functional, and nutritional qualities. An optimal drying process is required to preserve SPs to obtain concentrated nutrients and improve energy efficiency to be ecofriendly. Drying sweet potatoes using traditional methods such as sun or open-air drying was found to be a slow process that could result in a lower quality. Various advanced drying techniques, like vacuum, infrared, freeze drying, and pretreatments such as ultrasound and osmotic dehydration, have been developed and are successfully used globally. The best-fit thin-layer models (Hii, Page, two-term, logarithmic) utilized for drying SPs and appropriate modeling methods for optimizing drying procedures are also discussed.
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The sweet potato ( Ipomea batatas L Lam) is a famine crop with great potentials to supply energy and curb hidden hunger in developing countries. It is the only major root crop (often used as vegetable) with four nutrients that exceed 10% of the recommended daily amount (vitamin A/beta carotene; vitamin C; Fiber and potassium) Commendable research efforts have been dedicated to developing improved varieties of sweet potatoes for pest resistance; yield; stress tolerance; dry matter content; carotenoids (xanthophyll and pro-vitamin A) and mineral content. This paper presents an update on the research status on sweet potatoes and highlights areas for further research for the sustainable use of this cheap source of bioenergy and nutrients as a food security crop. Bio-fortification rather than transgenic research methods has been found to be more suitable for the incorporation of novel nutrients into the crop. Factors that affect the nutrient density and yield of sweet potatoes include: soil nutrient management practices, vine pruning and planting distances. Although they have seeds, sweet potatoes are better propagated with vine cuttings. The level of adoption of orange fleshed sweet potatoes is still low and the problems of seasonality, high costs of good quality planting materials, diversification of value added products and complexity of the production technique for the rural farmer need to be addressed. This crop requires improved research efforts for sustainable food security in developing countries.
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Food preference of Brachytrupes membranaceus and proximate analysis of the nymphal and adult stages of B. membranaceus was carried out in the Arboretum and laboratory of the University of Calabar. The nymphs of B. membranaceus were sourced from the wild. Materials used as feeds included Anarcadium occidentale leaf (AOL), Arachis hypogea leaves and nuts (AHL, AHN), Telfairia occidentalis leaves (TOL), Ipomoea batatas leaves and tubers (IBL, IBT), also mixtures of all the vegetables, broiler mash, and control. An insectarium made up of 20 block compartments covering an area of 15×15 m with a distance of 1 m block from each treatment was built in the University’s Arboretum. The treatments were arranged in a randomised complete block design with four replications. The nymphal stage of B. membranaceus was later introduced to the insectarium and fed with different rations. Data were collected several days to full maturity and weight gain at three weekly intervals till maturity. The results showed that B. membranaceus fed with vegetables and tubers recorded higher weight similar to those fed with broiler mash and mixtures. Proximate analysis of B. membranaceus shows protein source (53.4 g), dry matter content, average ash content (6.0 g), percentage lipid or fat (15.7 g), average crude fibre (6.3 g), average carbohydrate (15.20 g), macro and microelements. The result also showed the following amino acids; lysine (40.0), histidine (21.5), arginine (48.5), aspartic acid (73), threonine (18) serine (35), glutamic acid (150), proline (19.0), glycine (45.5), alanine (30.5), cystine (15.7), valine (37.8), methionine (20.5), isoleucine (45.8), leucine (55.9), tyrosine (24.6), and phenylalanine (38.5). Farming of B. membranaceus should be encouraged by poor resource farmers in Nigeria due to availability of their feed, its high protein contents and the presence of essential amino acid which is lacking in most in most Nigerian diets.
Chapter
The nutritional state of large segments of the African population remains alarming despite the positive socio-economic development that is taking place. The most significant nutritional problems include undernutrition, iron deficiency and vitamin A deficiency. Malnutrition and deficiencies also exacerbate a number of other diseases and health conditions. Besides undernutrition, the prevalence of overnutrition and obesity on the African continent are rising, as are the associated health conditions such as diabetes and coronary heart diseases. This chapter outlines the unique nutritional and bioactive properties of Traditional African Foods (TAFs) and their potential to contribute to the alleviation of undernutrition, overnutrition and associated health problems. Special emphasis is placed on vegetables, fruits, cereals, edible insects, small fish species, mushrooms, legumes, sesame, tuber and root crops. Some of the identified health benefits of these TAFs include lowering of serum cholesterol, anti-carcinogenic, anti-diabetic and anti-inflammatory, cardiovascular disease prevention and anti-hypertensive properties.
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Modern society has easy access to a vast informational database. The pursuit of sustainable green and healthy lifestyle leads to a series of food choices. Therefore, it is of importance to provide reliable, comprehensive and up-to-date information about food content including both nutritional and antinutritional elements. Nutrients are associated with positive effects on human health. Antinutrients, on the other hand, are far less popular for the contemporary man. They are highly bioactive, capable of deleterious effects as well as some beneficial health effects in man, and vastly available in plant-based foods. These compounds are of natural or synthetic origin, interfere with the absorption of nutrients, and can be responsible for some mischievous effects related to the nutrient absorption. Some of the common symptoms exhibited by a large amount of antinutrients in the body can be nausea, bloating, headaches, rashes, nutritional deficiencies, etc . Phytates, oxalates, and lectins are few of the well-known antinutrients. Science has acknowledged several ways in order to alter the negative influence antinutrients exhibiting on human health. Mechanical, thermal and biochemical approaches act synergistically to provide food with lower antinutritional levels. The purpose of this review was to synthesize the availability of antinutrients, clear their effect on the human body, and commemorate possible paths to disable them. This review provides links to the available literature as well as enables a systematic view of the recently published research on the topic of plant-based antinutrients.
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The nutritional state of large segments of the African population remains alarming despite the positive socio-economic development that is taking place. The most significant nutritional problems include undernutrition, iron deficiency and vitamin A deficiency. Malnutrition and deficiencies also exacerbate a number of other diseases and health conditions. Besides undernutrition, the prevalence of overnutrition and obesity on the African continent are rising, as are the associated health conditions such as diabetes and coronary heart diseases. This chapter outlines the unique nutritional and bioactive properties of Traditional African Foods (TAFs) and their potential to contribute to the alleviation of undernutrition, overnutrition and associated health problems. Special emphasis is placed on vegetables, fruits, cereals, edible insects, small fish species, mushrooms, legumes, sesame, tuber and root crops. Some of the identified health benefits of these TAFs include lowering of serum cholesterol, anti-carcinogenic, anti-diabetic and anti-inflammatory, cardiovascular disease prevention and anti-hypertensive properties.
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Low calcium intake, poor calcium absorption, excessive calcium losses, or some combination of these factors contribute to calcium deficiency diseases. Calcium insufficiency is associated with osteoporosis, hypertension and colon cancer among other diseases. For individuals who do not have access to milk and dairy products, do not tolerate them, or prefer not to consume them, plants may be alternative sources of calcium. However, calcium bioavailability may be low in plant foods because calcium forms complexes with oxalates, phytate and other competing minerals. The objective of this study was to compare the calcium content, digestibility and bioaccessibility in the leaves of spinach ( Spinacia oleracea) , sweet potato ( Ipomea batatas ), and drumstick tree ( Moringa oleifera ). Calcium content was analyzed in dry leaf powder by atomic absorption, followed by a two-stage in vitro digestion and dialysis against a mock serum solution to determine calcium digestibility and bioaccessibility. Moringa oleifera had higher calcium content than spinach and sweet potato leaves: 1.54±0.11% of dry matter for three Moringa samples (two African and one from India), and 0.99±0.001 and 1.06±0.001, respectively, in spinach and sweet potato leaves. The mean in vitro calcium digestibility was 1.62±0.08% in spinach, 3.4±0.68% in sweet potato leaves and 33.7±9.6% for Moringa . A dialysis system was designed to model bioaccessibility of calcium, revealing that bioaccessible calcium in sweet potato leaves was a non-significant 1.4 times higher and in Moringa was 9.2 to 19.4 times higher than in spinach. Therefore, the calcium contained in Moringa leaves does not appear to be associated with poorly bioavailable complexes such as oxalate. We confirmed previous reports that bioaccessibility of the calcium is low in spinach. These findings imply that increased utilization of Ipomea batatas and Moringa oleifera leaves might increase calcium intake in people in tropical and warm temperate regions where these plants grow, or these plants might become a valuable export crop.
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