scholarly journals Screening of traditional South African leafy vegetables for selected anti-nutrient factors before and after processing

2018 ◽  
Author(s):  
◽  
Humaira Essack

The present study investigated the effect of processing on anti-nutritional factors of thirteen traditional leafy vegetables collected in KwaZulu-Natal, South Africa. The purpose of this study was to determine whether processing reduced anti-nutrient levels of the species. Three boiling parameters were used with a ratio of 1:4 vegetable to water for a time period of 0, 5 and 15 min. The vegetables studied were: Amaranthus dubius, Amaranthus hybridus, Asystasia gangetica, Bidens pilosa, Ceratotheca triloba, Chenopodium album, Emex australis, Galinsoga parviflora, Guilleminea densa, Momordica balsamina, Oxygonum sinuatum, Physalis viscosa and Solanum nigrum. From this study, it was determined that non processed samples contained anti-nutrients such as tannins (0.01–0.14 mg/ml), phytic acid (0.002–0.059 mg/ml), alkaloids (3.6–11%), oxalic acid (85.2–1079.3 mg/ml) and cyanogenic glycoside (17–33 mg/100g). Solanum nigrum was the highest in tannin content (0.14 mg/ml).Ceratotheca triloba was the highest in phytic acid content (0.06 mg/ml). Momordica balsamina (11.1%) and Physalis viscosa (10.3%) ranked the highest overall in alkaloid content. Ceratotheca triloba (1079.3 mg/ml), Amaranthus hybridus (796 mg/ml) and Oxygonum sinuatum (673.9 mg/ml) were the highest in oxalic acid. Asystasia gangetica (33.3 mg/g), Ceratotheca triloba (32.6 mg/g), Momordica balsamina (32.5 mg/g), Physalis viscosa (32.3 mg/g) and Solanum nigrum (32.2 mg/g) were the highest in cyanogenic glycoside. All anti-nutrients were reduced significantly through boiling in all the species. The results of this study provide evidence that the local traditional vegetables upon which the population is so reliant upon, are important contributors in micronutrient malnutrition in developing countries and can be eliminated through common boiling methods for a minimum of 5 and maximum of 15 minutes.

2003 ◽  
Author(s):  
◽  
Sharlynn Beekrum

Leafy vegetables provide valuable nutrients to humans. Indigenous or traditional vegetables are rapidly being replaced by exotic plants. These vegetables are often costly and not easily available to communities. This study was undertaken to determine the nutritional composition of the leaves of twenty traditional leafy vegetables namely Solanum nigrum, Physalis viscosa, Cucumis metuliferus, Momordica balsamina, Amaranthus spinosus, Amaranthus hybridus, Amaranthus dubius, Asystasia gangetica, Justicia flava, Emex australis, Oxygonum sinuatum, Bidens pilosa, Cleome monophylla, Portulaca oleracea, Wahlenbergia undulata, Senna occidentalis, Chenopodium album, Ceratotheca triloba, Galinsoga parviflora and Centella asiatica from different locations in Kwa-Zulu Natal. The leafy vegetables were analysed for protein, moisture, fat, fibre, carbohydrates, ash, energy values and nutritionally valuable mineral elements (Ca, P, Na, Zn, Mg, Mn and Fe).


2012 ◽  
Author(s):  
◽  
Berushka Padayachee

Immunomodulation using plants is of primary interest in scientific communities because it provides an alternative to conventional chemotherapy for a wide range of diseases. It is based on the ability of the plants to effectively modulate immune functions, thus being able to promote positive health and maintain the body’s resistance to infection. This research is aimed to evaluate the immunomodulatory potential of fourteen traditional leafy vegetables from Kwa-Zulu Natal, South Africa on human peripheral blood mononuclear cells (PBMC). In this study the methanolic and aqueous extracts were screened for lymphocyte proliferation using the MTT assay. The cytokine response was evaluated by measuring the secretion of interleukin 10 (IL-10) and interferon-gamma (IFN-γ) using the ELISA assay. The subpopulation of T cells viz., CD4+, CD8+, NK and B cells were measured by flow cytometry. Most of the methanolic extracts stimulated PBMC’s whilst a few suppressed lymphocyte proliferation. Most of the aqueous extracts were inactive. The methanolic extracts of Amaranthus hybridus and Centella asiatica stimulated PBMC’s and showed an increase in IFN-γ secretion and the CD8+ cytotoxic T cells and B cells. Thus, they induced the Tc-1 immune response and stimulated cell mediated immunity. The methanolic extracts of Asystasia gangetica, Bidens pilosa, Emex australis, Justicia flava Momordica balsamina, Oxygonum sinuatum, Senna occidentalis and Sonchus oleraceous and the aqueous extracts of Amaranthus spinosus and Asystasia gangetica, Ceratotheca triloba, Oxygonum sinuatum, Physalis viscosa and Sonchus oleaceous stimulated PBMC’s and showed an increase in IL-10 secretion and the CD8+ cytotoxic T cells and B cells. Thus, they induced the Tc-2 immune response and stimulated humoral immunity. Also, the methanolic extracts of Amaranthus spinosus and Ceratotheca triloba and the aqueous extracts of Bidens pilosa and Justicia flava increased both IL-10 and IFN-γ secretion and the CD8+ vii cytotoxic T cells indicating the stimulation of both the Tc1 and Tc2 cytokine profiles. The elevated secretion of IFN-γ and IL-10 caused by the extracts can be attributed to the CD8+ cytotoxic T cells and B cells. The findings of this study show that leafy vegetables hold promise as immunomodulatory candidates. They may enhance cell-mediated immune functions by a pro-inflammatory response whilst some can promote humoral immune functions by means of an anti-inflammatory response. Further investigation should be considered on the effect of the extracts on other immune parameters.


2021 ◽  
Vol 5 ◽  
Author(s):  
Raquel Kissanga ◽  
Joana Sales ◽  
Margarida Moldão ◽  
Vitor Alves ◽  
Herose Mendes ◽  
...  

In Southern Angola, numerous non-woody forest products are sold at local markets, namely in Lubango (Huíla Province). Such is the case of herbaceous wild plants, locally known as lombi, which are sold fresh throughout the year and cooked as a vegetable. Although these wild leafy vegetables are commercialized and widely used in local food, there is still a lack of scientific knowledge about their properties. Thus, this study aimed to identify and characterize the species sold, and to determine their nutritional and functional properties. Our results revealed that three species—Amaranthus hybridus, Bidens pilosa, and Galinsoga parviflora—are usually sold at Lubango markets and consumed by local populations. These are annual exotic plants, native to Southern America, and usually occur spontaneously in croplands or disturbed areas, but can also be cultivated, particularly A. hybridus. Physico-chemical analyses of lombi species and mixtures sold at the markets included measurements of moisture, protein, lipid, and mineral content, as well as total phenolic content, antioxidant activity, and levels of heavy metal contaminants. The results revealed that lombi contain a significant amount of protein (20–28 g/100 g, dry basis), high values of macronutrients and micronutrients, as well as of phenolic compounds (10–40 mg GAE/g) and a good antioxidant capacity. Given the availability of lombi throughout the year, our study demonstrated the importance of wild edible plants in Angola, both as a valuable natural resources and as a complementary food sources, as well as additional sources of income for many families.


2007 ◽  
Author(s):  
◽  
Mashudu Mudzwiri

Eighteen traditionally leafy vegetables consumed as food or medicinal compounds by a majority of people in the KwaZulu Natal province of South Africa were analysed for the presence of potentially harmful chemicals (antinutrients) and for their toxicity and mutagenicity. The purpose of the study was to determine whether leafy vegetables were safe for human consumption. Chemical analysis showed that none of the vegetables contained cyanogenic glycosides, however all the vegetables contained oxalic acid ranging from 24.1 mg/ml to 798.2 mg/ml with Solanum nigrum, Portulaca oleracea and Mormodica balsamina showing the highest concentrations. Most of the vegetables contained negligible amounts of phytic acid and saponins, except for Momordica balsamina (3.01 mg/ml and 1.83 mg/ml, respectively). Fourteen of the plants contained alkaloids with Portulaca oleracea having the highest content (1.53 g total alkaloids/5 g leaf material). Eight of the plants were found to inhibit trypsin activity. These chemical analyses were carried out in duplicate and the mean and standard deviation were used. The Ames test revealed that none of the leafy vegetables produced a mutagenic frequency above 1, except 10 000 µg/ml organic extract of Senna occidentalis (mutagenecity considered at mutagenic frequency above 2), thus none were considered mutagenic. All 18 organic extracts did not kill off more than 50% brine shrimp and were thus considered non-toxic. On the other hand the aqueous extracts of seven vegetables, namely, Physalis viscosa, Amaranthus dubius, Justicia flava, Bidens pilosa, Senna occidentalis, Chenopodium album and Ceratotheca triloba, killed more than 50% of the shrimp and are thus considered toxic above 100 µg/ml. The MTT assay carried out on the organic extracts indicated that 17 vegetables did not kill off more than 50% of HepG2 cells and were thus considered non-cytotoxic. The aqueous extracts of four vegetables, namely, Justicia flava, Asystasia gangetica, Momordica balsamin and Senna occidentalis, however killed more than 50% of the shrimp and were thus considered cytotoxic above 1 000 µg/ml. It may be concluded from the antinutrient analyses and the bioassays on the 18 vegetables that caution needs to be maintained with the consumption of certain leafy vegetables included in this study, especially Senna occidentalis.


2014 ◽  
Vol 27 (1) ◽  
pp. 128-142
Author(s):  
Ali A. Sahi ◽  
Ali H. Abdul-Kareem ◽  
Basim A. Jaber

1992 ◽  
Vol 42 (2) ◽  
pp. 109-116 ◽  
Author(s):  
Manju Gupta ◽  
Neelam Khetarpaul ◽  
B. M. Chauhan

2004 ◽  
Vol 91 (2) ◽  
pp. 287-293 ◽  
Author(s):  
Lena Davidsson ◽  
Ekhard E. Ziegler ◽  
Peter Kastenmayer ◽  
Peter van Dael ◽  
Denis Barclay

Infant formulas based on soyabean protein isolate are often used as an alternative to cows'-based formulas. However, the presence of phytic acid in soya formulas has raised concern about the absorption of trace elements and minerals from these products. The aim of the present study was to evaluate mineral and trace element absorption from regular and dephytinised soya formula in healthy infants. Soyabean protein isolate with a relatively low native content of phytic acid was used for production of a regular soya formula (300 mg phytic acid/kg liquid formula) and an experimental formula was based on dephytinised soya protein isolate (<6 mg phytic acid/kg liquid formula). Using a crossover study design, apparent mineral and trace element absorptions were measured by a stable isotope technique based on 72 h faecal excretion of non-absorbed stable isotopes (Zn, Fe, Cu and Ca) and by the chemical balance technique (Mn, Zn, Cu and Ca) in nine infants (69–191 d old). Fe absorption was also measured by erythrocyte incorporation 14 d after intake. The results from the present study demonstrated that Zn absorption, measured by a stable isotope technique, was significantly greater after dephytinisation (mean value 16·7 v. 22·6 %; P=0·03). No other statistically significant differences between the two formulas were observed. The nutritional benefit of dephytinisation was marginal in the present study. Based on these results, the use of soyabean protein isolate with low native content of phytic acid should be promoted for production of soya formulas and adequate addition of ascorbic acid to enhance Fe absorption should be ensured in the products.


2010 ◽  
Vol 53 (4) ◽  
pp. 975-980 ◽  
Author(s):  
Juliana da Silva Agostini ◽  
Rosicler Balduíno Nogueira ◽  
Elza Iouko Ida

The objective of this work was to investigate the germination of hybrid sunflowers BRS191 and C11 as a means of lowering phytic acid (PA) content by enhancing the activity of endogenous phytase and acid phosphatase. The concentration of PA in hybrid sunflower achenes varied from 2.16 to 2.83g/100g of sample (p < 0.05). The phytase and acid phosphatase activities of sunflowers BRS191 and C11 were the highest on the 4th and 5th days of germination, respectively, with the release of the phosphorus. These results indicated that hybrid sunflower PA reduced and enhance phytase activity at distinct germination periods, which could open up the possibility of applying these enzymes in the control of PA content in cereals, thus improving their nutritional value.


2008 ◽  
Vol 6 (2) ◽  
pp. 36-44
Author(s):  
DIAN SRI PRAMITA ◽  
SRIiii HANDAJANI ◽  
DIAN RACHMAWANTI

Pramita DS, Handajani S, Rachmawanti D. 2008. The effect of heating technique to phytic acid content and antioxidant activity of velvet bean (Mucuna pruriens), butter bean (Phaseolus lunatus) and jack bean (Canavalia ensiformis). Biofarmasi 6: 36-44. Koro is a kind of local bean which has many varieties. The nutrition of koro is not different with soy, especially carbohydrate and protein which high enough, and has a low-fat content. However, koro also contains some harmful compounds, HCN which poisoned and phytic acid which an antinutritional compound. Besides as antinutritional compound, phytic acid has a positive role, i.e. as an antioxidant. Besides phytic acid, legume also contains the compounds of phenol and vitamin E that have antioxidant activity. The aims of this research were to determine the contents of phytic acid and antioxidant activity, and to determine the effect of heating technique on phytic acid and antioxidant activity of velvet bean, butter bean, and jack bean. The materials used were velvet bean, butter bean and jack bean obtained from Batuwarno, Wonogiri, Central Java. This research used a Completely Randomized Design (CRD) with five kinds of treatment, each treatment consisted of three replications. The treatments given were soaking by 3 days (P1), steaming (P2), boiling (P3) and pressure cooker (P4), which compared to a raw bean without heating treatment (P0). The investigated factors were phytic acid and antioxidant activity (DPPH Radical Scavenging Ability method). The results of this research showed the phytic acid content of velvet bean, butter bean and jack bean from the treatment of P0, P1, P2, P3 and P4 were degraded. The phytic acid of velvet bean of P0, P1, P2, P3 and P4 treatment were 10.87, 8.94, 4.56 and 1.72 and 1.46 mg/db, respectively; on butter bean were 11.78, 8.75, 4.77, 1.73 and 1.61 mg/db, respectively; while on jack bean were 9.04, 1.99, 1.39, 1.42 and 1.21 mg/db. The result of variance analysis showed the phytic acid content was significantly different (p<0.05). Antioxidant activity showed the increase from P0 to P1, then the degradation process at P2, P3, and P4. Antioxidant activity at velvet bean were 74.10%, 86.49%, 84.73%, 83.59% and 79.51%, respectively; at butter bean were 4.5%, 7.19%, 6.07%, 6.30% and 6.28%, respectively; at jack bean were 14.64%, 8.55%, 5.84%, 5.17% and 3.58%. The result of variance analysis showed antioxidant activity at velvet bean and jack bean was significant, while at butter bean for P1, P2, P3, and P4 were not significant. The conclusion that could be taken away from this research were heating techniques had an effect on the degradation of phytic acid at all kind of bean used, and also had an effect on the antioxidant activity at velvet bean and jack bean.


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