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Phenolic profile and antioxidant activity of brown and yellow varieties of Tigernut (Cyperus esculentus L.).

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Olalekan J. Adebowale at The Federal Polytechnic Ilaro
Olalekan J. Adebowale
Oladele A.K
Oladele A.K
Oluwaseun Peter Bamidele at University of Venda
Oluwaseun Peter Bamidele
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... The valorization of these wastes for the development of active food packaging could promote more sustainable materials while aligning with the principles of a circular economy. Its low cost, and richness in different polymeric compounds, such as starch, lignin, arabinoxylans, and cellulose [5], and polyphenols with antioxidant and antimicrobial activity, such as ferulic and p-coumaric acids or flavonoids [6], confers interesting and promising properties to this material for this purpose. Likewise, considering the non-cost of the horchata solid residue, the final cost of the packaging material would be reduced since the ratio of polymer is lower in the final material. ...
... CIE L*a*b* color coordinates were obtained from the reflectance of an infinitely thick layer of the material (R∞, Equation (6)) by considering D65 illuminant and 10 • observer, according to Hutchings [16]. Chroma (C* ab ) and hue (h* ab ) and the color difference between the different composite films and the neat PHBV film (control) were also determined by equations (Equations (6) to (8)). ...
Biocomposites Based on PHBV and the Lignocellulosic Residue from Horchata Production
Article
Full-text available
  • Apr 2025
The use of agro-industrial residues in the development of packaging materials is a topic of interest from a sustainable perspective, as it promotes biodegradability, reduces production costs, and aligns with the concept of a circular economy. The aim of this work was to develop and characterize biodegradable composite films based on Poly 3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV) and the tiger nut horchata solid residue (HSR) at different ratios. The obtained composites were evaluated as to their suitability as food active packaging materials in terms of microstructure, water content and solubility, mechanical, barrier and thermal properties, and total phenolic content and antioxidant capacity. The incorporation of HSR into the PHBV matrix led to more opaque, darker reddish films and promoted significant changes in their mechanical and barrier properties. Specifically, the composite films showed lower water vapor barrier capacity and reduced tensile strength (43–81% lower TS) and elongation at break (46–77% lower Ɛ values) while the rigidity increased or maintained when using up to 20% wt. of HSR. In contrast, the incorporation of the HSR provided the films with remarkable antioxidant capacity and effective light-blocking capacity, which could be of great interest for food preservation, as active packaging materials. The total phenol content of the composites increased in line with the increment of the HSR content, ranging from 9 to 34 mg GAE/100 g film.
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... Although low in protein content, the essential amino acids such as methionine, threonine, and lysine are present in tigernut (Yu et al., 2022). Tigernut contains high content of dietary fibre and polyphenols (Oladele et al., 2017;Yu et al., 2022). Pharmacological tests showed that alcoholic extracts of tigernut have antidiabetic effect (Badejo et al., 2020), anticancer (Achoribo and Ong, 2017), anticonvulsant and antioxidant properties (Ayyanna et al., 2020). ...
... To the best knowledge of the authors, this is the first report on the phenolic profile of tigernut residues. The phenolic compounds detected in the tigernut residue flours have been reported in whole tigernut flour (Oladele et al., 2017) and their products (Babiker et al., 2021). Phenolic compounds such as caffeic acid and Quercetin are bioactive compounds with antioxidant activity (Apeah-Bah et al., 2017). ...
CHEMICAL, TECHNO-FUNCTIONAL, AND ANTIOXIDANT PROPERTIES OF TIGERNUT (CYPERUS ESCULENTUS L.) RESIDUE FLOURS
Article
Full-text available
  • Oct 2023
Tigernut processing generates nutritionally-rich residue, mostly discarded as waste. This research reports for the first time the amino acid profile, phenolic profile, and pasting properties of tigernut residues. Yellow and brown tigernut residues were analysed for amino acid and phenolic profile, antioxidant, techno-functional and pasting properties. The total essential amino acids were 49 and 56% for yellow and brown tigernut residue flours, respectively. The flavonoid content and ferric reducing antioxidant property were 0.91 and 0.32 mg GAE/ g, and 3.43 and 1.41 AAE/ g for yellow and brown residue, respectively. Caffeic acid (29 – 56 mg/ 100 g), ferulic acid (39 mg/ 100 g), vanillic acid (38 mg/ 100 g), Quercetin (48 mg/ 100 g), and phenyl acetic acid (3 – 68 mg/ 100 g) occur in abundance in the residue flours. The oil absorption capacity (3.40 ml/ g), L* value (63.78), and b* value (15.61) were higher in yellow than in brown residue. Brown tigernut residue flour cooked faster (5.77 min) than yellow tigernut residue flour (6.97 min). Some essential amino acids detected were lysine, leucine, and methionine. The reports obtained in this work showed that tigernut residues have the potential to be incorporated in food due to their richness in essential amino acids, phenolic compounds, and antioxidant activity
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... The total content of polyphenols found in the present study was 3-fold higher than a previous study. 9 Moreover, previous studies reported ferulic acid and sinapinic acid as the predominant polyphenols in the tiger nuts 27 ; vanillic acid, vanillin and trans-cinnamic acid as the most abundant in tiger nut oils 28 ; and p-coumaric, quercetin and cinnamic acids as prominent polyphenols in the brown variety of TNB fermented with kefir grains. 29 Data are shown as mean±SD. ...
Potential bioaccessibility and bioavailability of polyphenols and functional properties of tiger nut beverage and by-product during in vitro digestion
Article
Full-text available
  • Jul 2024
“Horchata de chufa”is a beverage produced from tiger nut tubers which yields high amount of by-product. This study explored the functional properties of the Spanish tiger nut beverage (TNB) and...
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... The protein quantities of raw and sprouted 'Sarıs ßeker' and 'Balyumru' tigernuts were established as 9.84% and 11.27% to 7.18% and 8.91%, respectively ( € Ozcan et al., 2021). Total phenolic content of yellow tigernut tuber was established to be 351 mg/100 g, while total phenol amount of brown tigernut is found to be 134 mg/100 g (Oladele et al., 2017). While total phenol results of raw tigernut tubers are recorded to be between 4.01 and 3.98 mg GAE/100 g, antioxidant activities of germinated tigernut tubers were reported to be between 33.22 and 45.0 lg mL À1 (Adebayo & Arinola, 2017). ...
The role of germination on changes in bioactive properties, fatty acids and biogenic element profiles of tigernut tubers germinated at different times
Article
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In this study, the effects of different germination times on some chemical characteristics, total phenol and flavonoid quantity, antioxidant capacities, phenolic and fatty acid compositions and biogenic element contents of tigernut tubers were investigated. Total phenolic and flavonoid quantities of raw and tigernut tubers germinated at certain germination periods were reported to be between 24.40 (first period of germination) and 63.84 mgGAE/100 g (third period of germination) to 33.00 (control) and 184.24 mgRE/100 g (third period of germination), respectively. Antioxidant capacities of raw and germinated tigernut tubers were recorded to be between 0.91 (first period of germination) and 1.57 mmolTE kg⁻¹ (third period of germination). Gallic (except control), catechin, caffeic acid, rutin and kaempferol values of tubers were higher especially in the second and third periods of germination compared to the first period of control and germination. Oleic and linoleic acid values of raw (control) and germinated tigernut oils were identified between 69.41% (third period of germination) and 72.53% (control) to 9.77 (control) and 11.77% (third period of germination), respectively. P, K, Ca, Mg, S and Na were the dominant elements of raw and germinated tigernuts. The bioactive properties, phenolic component amounts and element quantities of germinated tubers were increased.
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... Since most of the compounds detected in TDB were aromatic in nature, we propose that the hydroxyl group and/or aromatic ring could play a significant role due to the stabilization of the radicals via tautomerization. Our present data were in agreement with previous studies for tiger nut (Oladele et al., 2017) and date fruit (Shahdadi et al., 2015). ...
Tiger nut (Cyperus esculentus L.) and date palm (Phoenix dactylifera L.) fruit blend mitigates hyperglycemia, insulin resistance and oxidative complications in type-2 diabetes models
Article
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Tiger nut and date fruit are chewy with sweet taste and are popularly consumed as food either alone, mixed or paired with other fruits, seeds and vegetables. They are locally used to treat diabetes and were separately reported to attenuate hyperglycemia in various animal models of diabetes. However, effect of tiger nut and date fruit mixture on key diabetes related parameters has not yet been reported. Therefore, we investigated the antidiabetic and antioxidant effects of the tiger nut and date blend (TDB) using in vitro and in vivo models. The TDB was prepared in equal ratio (1:1). For the in vivo study, mixture was included in the diet at 5% and 10% and feed the type 2 diabetic rats for 4 weeks. The diabetic untreated rats showed significant (p < .05) hyperglycemia, hyperlipidemia, insulin resistance and oxidative stress. Consumption of the TDB blend, significantly (p < .05) reduced fasting blood glucose by 71% and 52% in the groups treated with high and low doses respectively. In addition, intake of TBD blend demonstrated significant (p < .05) antihyperlipidemic, ameliorated insulin resistance and oxidative stress in the treated groups. The effects were more prominent in group supplemented with the 10% of the TDB and attributed to some promising ingredients detected. In conclusion, dietary supplementation of TDB exhibited antidiabetic action and could be due to the phytochemicals assessed. Practical applications Inclusion of functional foods such as tiger nut and date fruit in daily diet is proved to be highly beneficial in controlling type‐2 diabetes and its associated complications. Our results show that tiger nut and date fruit blend can effectively reduce hyperglycemia and oxidative damage, improve insulin sensitivity in type‐2 diabetes rat model. Hence, the data shows the potential of tiger nut and date fruit blend to promote scientific basis of the dietary application of tiger nut and date fruit blend as a functional food for the remedy of diabetes and its associated complications.
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... Moreover, authors indicated that the continuous degradation of the lignin structure is a key factor influencing phenolics extraction and content in the final extracts, particularly for p-coumaric and ferulic acids. Oladele et al. (94) also studied the polyphenols profile of different types of tiger nuts and they found high concentrations of ferulic acid (34-58 mg 100 g dm −1 ), p-hydroxybenzaldehyde (≈ 16 mg 100 g dm −1 ), p-coumaric acid (≈ 17 mg 100 g dm −1 ), and sinapinic acid (≈ 21 mg 100 g dm −1 ). ...
Chemical Composition and Bioactive Antioxidants Obtained by Microwave-Assisted Extraction of Cyperus esculentus L. By-products: A Valorization Approach
Article
Full-text available
  • Jul 2022
Tiger nut is highly appreciated in the Mediterranean basin by the large number of nutritional advantages offered by a beverage, called “horchata,” which is directly obtained from the tuber of Cyperus esculentus L. However, the current tiger nut harvesting and processing practices generate a large number of residues, mainly a solid by-product after processing and the plant that remains spread out in the fields. In this work the plant residues have been fully characterized to get a clear picture of the possibilities for its valorization to generate products with high added value. Several analytical techniques have been applied to obtain data to assess the real possibilities of these residues in advanced applications in the food, packaging and nutrition sectors. Results on the compositional and elemental analysis, monosaccharide composition, phenolic concentration, and antioxidant capacity were obtained from the dry powder (DP). The high content of α-cellulose (47.2 ± 1.8%) in DP could open new possibilities for these residues as raw material in the production of cellulose nanoentities. Many essential minerals with nutritional interest (Na, Mg, Ca, Mn, Fe, Cu, and Zn) and free sugars (xylose, arabinose, glucose, and galacturonic acid) were identified in the DP making it an interesting source of valuable nutrients. The total carbohydrate content was 171 ± 31 mg gdm–1. In addition, microwave-assisted extraction (MAE) was used to obtain extracts rich in polyphenolic compounds. A Box–Behnken design (BBD) was used, and the optimal extraction conditions predicted by the model were 80°C, 18 min, ethanol concentration 40% (v/v), and solvent volume 77 mL, showing an extraction yield of 2.27 ± 0.09%, TPC value was 136 ± 3 mgGAE 100 gdm–1 and antioxidant capacity by the ABTS method was 8.41 ± 0.09 μmoltrolox gdm–1. Other assays (FRAP and DPPH) were also tested, confirming the high antioxidant capacity of DP extracts. Some polyphenols were identified and quantified: p-coumaric (7.67 ± 0.16 mg 100 gdm–1), ferulic (4.07 ± 0.01 mg 100 gdm–1), sinapinic (0.50 ± 0.01 mg 100 gdm–1) and cinnamic acids (1.10 ± 0.03 mg 100 gdm–1), 4-hydroxybenzaldehyde (1.28 ± 0.06 mg 100 gdm–1), luteolin (1.03 ± 0.01 mg 100 gdm–1), and naringenin (0.60 ± 0.01 mg 100 gdm–1). It can be concluded that C. esculentus L. residues obtained from the tiger nut harvesting and horchata processing could be an important source of high value compounds with potential uses in different industrial sectors, while limiting the environmental hazards associated with the current agricultural practices.
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... Also, in the same previous table (8) [35,10,6,32,37]. ...
Comparative Characteristics Study of Moringa (Moringa peregrina), Terminalia (Terminalia Billerica) and Tiger nut (Cyperus esculentus) Oils
Article
Full-text available
  • Aug 2021
Vegetable oils constitutes are an important part of human diets. The objective of this research is to study the utilizing the seeds of Terminalia bellerica, Moringa peregrine, and tubers of Tiger nut to produce oils that can be utilized successfully as sources of edible oil for human consumption. Fatty acids compositions of oils were analyzed by GLC, phenolic compounds of oils and meals were identified and determined using HPLC, minerals content of meals were analyzed by atomic absorption spectrophotometer. Also, amino acid content of meals determination by amino acid analyzer. Moringa peregrina seed had the highest oil content (50.09 %) followed by Terminalia bellerica seed (36.01%) and Tiger nut (19.33 %) respectively. Moringa peregrina recorded the highest oxidative stability compared to the stability of Terminalia and Tiger nut oil. Moringa peregrina seed oil had the highest percentage of oleic acid (76.91%) followed by Tiger nut tubers oil (69.53%), but Terminalia bellerica seed oil had the lowest percentage (27. 09 %). Moringa peregrina seed oil contained a higher amount of total tocopherols compared to other samples. The result indicates that Moringa peregrine and Terminalia bellerica, and Tiger nut oil could be used as a good source of edible oil.
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RETRACTED ARTICLE: Starch Recovery Process from the Tiger Nut Horchata Processing Waste
Article
Full-text available
  • Aug 2024
  • FOOD BIOPROCESS TECH
Tiger nut horchata solid residue (HSR) has high starch content (about 23%, dry basis) that can be recovered to valorise this waste, together with other valuable components, such as oil, fibres, or phenolic compounds. In this study, a chemical-free, sustainable process was proposed to obtain starch with good yield and purity. This consists of a high-speed homogenisation step with distilled water, followed by filtration and phase separation by density in the slurry to obtain a starch-rich sediment that can be isolated by decantation. Five minutes of homogenisation at 10,200 rpm allows for obtaining 14.5 g of starch powder per 100 g of dried HSR, with a purity of about 85% and WI of 94.97. Applying 1 washing cycle to the filtering residue increased the starch powder yield up to 17 g/100 dried HSR, without notable losses in starch purity, whereas centrifugation at 15,000 g for 1 h in the phase separation step highly reduced separation time, increasing starch purity up to 92%. Thus, it was possible to recover up to 70% of the starch present in the HSR. The obtained starch had similar morphological characteristics, crystallinity degree, and gelatinisation behaviour to that present in the tiger nut tubers, exhibiting similar thermal stability to that reported for other native starches. Therefore, HSR can be used as a starch source for different uses.
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Quantitative genetics analysis of autism according to sex hormones
Article
Full-text available
  • Nov 2022
Quantitative genetics analysis of autism according to sex hormones
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Changes in Saponins Content of Some Selected Nigerian Vegetables during Blanching and Juicing
Article
Full-text available
  • Mar 2013
Saponin, a secondary plant metabolite acts as both antinutrient and antioxidant in humans. It is usually affected by different processing methods, majorly heating. Though, vegetables are usually subjected to processing before consumption, however, recent interest in vegetable juice is gaining ground among the populace without consideration to the level of antinutrient and other toxic constituents that may be concentrated by juicing. Some selected vegetables, commonly consumed in south western Nigeria were evaluated for saponins content in the fresh, blanched and juiced forms using standard laboratory procedures. Variation exists in saponin content of vegetable and their products. Highest value of saponin was observed as follows; fresh Teliferia occidetalis 1332.70mg/100g; blanched Teliferia occidentalis 918.77mg/100g and juice Manihot esculenta 2286.82mg/100g dry weight. While lowest was observed in Talinum triangulare 123.82mg/100g; launae taraxacifolia 141.75mg/100 and Basella rubra 132.03mg/100g dry weight respectively. Observations showed that blanching and juicing affected the saponin content of the vegetables differently, while the blanching reduced the content of saponin in most of the vegetables, juicing, however, concentrated some vegetables and reduced some. Also, saponin content of vegetables varies and affected by different processing methods. Thus, vegetable juice must be taken with caution by people vulnerable to saponin.
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Blanching influences the phenolics composition, antioxidant activity, and inhibitory effect of Adansonia digitata leaves extract on α -amylase, α -glucosidase, and aldose reductase
Article
Full-text available
  • May 2016
Adansonia digitata (A. digitata) leaves serve as food and have several medicinal uses in many parts of the world. This study evaluated the influence of blanching on the phenolics composition, antioxidant activity, and inhibitory effect of methanol extract of A. digitata leaves on the activities of some key enzymes (α‐amylase, α‐glucosidase, and aldose reductase) implicated in type 2 diabetes (T2D) in vitro. Reverse‐phase HPLC analysis revealed that the leaves had appreciable levels of flavonoids and phenolic acids, including catechin, epicatechin, rutin, quercitrin, quercetin, kaempferol, and luteolin (flavonoids); gallic, chlorogenic, caffeic, and ellagic acids (phenolic acids). Blanching caused significant (P < 0.05) decrease in the flavonoids and phenolic acids contents; DPPH* (2,2 diphenyl‐1‐picrylhydrazyl radical) and ABTS*⁺ [2,2‐azinobis (3‐ethyl‐benzothiazoline‐6‐sulfonic acid) radical cation] scavenging ability; reducing power; and Fe²⁺‐induced lipid peroxidation inhibitory capacity of the extract. Similarly, the inhibitory effect of the extract on the activities of α‐amylase, α‐glucosidase, and aldose reductase was significantly (P < 0.05) reduced due to blanching. Thus, A. digitata leaves extract could be effective for the management of T2D due to its flavonoids and phenolic acids content, antioxidant properties, and inhibitory potency on the activities of α‐amylase, α‐glucosidase, and aldose reductase. However, blanching militated against the levels of these functional attributes of the leaves and, therefore, may not be recommended for their optimal retention.
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Effects of blanching time/temperature combination coupled with solar-drying on the nutritional and microbial quality of indigenous leafy vegetables in Kenya
Article
Full-text available
  • Dec 2015
The abundance of indigenous leafy vegetables during the rainy seasons and the traditional preservation systems leads to post-harvest losses on nutrients. There is need to reduce these losses by seeking an alternative relatively cheaper, hygienic and locally adaptable preservation method. Solar drying could be a useful dehydration option. No sufficient data is available on a suitable combination of solar drying and blanching protocol for preservation of ILVs in Kenya. This study investigated the effects of controlled blanching time/temperature combination coupled with solar-drying on the nutritional and microbial load of three ILVs in finding a suitable preservation technique. The ILVs commonly consumed in Kenya, spiderplant (Cleome gynandra), slenderleaf (Crotalaria ochroleuca) and cowpeas (Vigna unguiculata) were used. Two blanching conditions (80 o C/10 min and at 90 o C/5 minutes) were tested. Blanching at 100 o C for 30 min, followed by open sun-drying was used as control, while conventional oven drying of the ILVs was used as standard for comparison. Greatest nutrient loss was observed for ILVs that were blanched at 100 o C for 30 min, then sun-dried. Most nutrients were retained at 80 o C/10 min compared to those retained at 90 o C/5 min. Microbial load (5.3-5.6 cfu/g) was significantly lower for solar dried ILVs (p<0.05) blanched at 90 o C/5 min. This indicates that blanching at 80 o C/10 min followed by solar drying is a potential option to be used as a local preservation technique for ILVs in Kenya.
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UNDERUTILIZED INDIGENOUS VEGETABLE (UIV) IN NIGERIA: A RICH SOURCE OF NUTRIENT AND ANTIOXIDANTS-A REVIEW
Article
Full-text available
  • Jan 2015
Nigeria is endowed with varieties of indigenous vegetables which are not only known for their rich food nutrient content but also, as health promoting foods. Among which is Trichosanthes cucumerina, Solanum macrocarpon, Amaranthus virides, and Crassocephalum crepidoides. The purpose of this article is to review information available in scientific literature on the antioxidant, medicinal, pharmacological and biological activities of the plant. Searches were made and relevant information obtained from online resources such as Google search, Google Scholar, PubMed and Medline. Only literature highlighting the antioxidant, medicinal, pharmacological, biological and biochemical activities of the plant were selected for this review. There had been an increase interest in sources of natural antioxidants over the years as synthetic antioxidants such as Butylated Hydroxyl Anisole (BHA) and Butylated Hydroxyl Toluene (BHT) though effective in their operations as antioxidants possess side effects which are detrimental to human health. Plants have been established to be good source of natural antioxidants by previous studies. The antioxidant potential and nutritional values arising from the rich polyphenol content of these vegetables are discussed in this review. The vegetables discuss in this review can be said to be useful, inexpensive and readily available food resources, not just for it nutritional contents but as food which has the ability to prevent and control diseases arising from oxidative damages caused by free radicals and reactive oxygen species (ROS). Five vegetable species have been reviewed and this includes Trichosanthes cucumerina, Solanum macrocarpon, Amaranthus virides, and Crassocephalum crepidoides. The antioxidants and nutritional value of these vegetables is no longer in doubt. It is expected that this review will be useful to researchers, nutritionist, herbal medical practitioners and agriculturists, and would also encourage optimum exploitation of the plants for its several benefits .
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b>Tiger Nut ( Cyperus Esculentus ): Composition, Products, Uses and Health Benefits - A Review</b
Article
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  • Aug 2014
This paper is a review on little history and the composition of Tigernut ranging from proximate, mineral and amino acid content. The paper further explains the kind of phytochemicals and antinutrients that can be found in tigernut .The kind of microorganisms which could be found on tigernut was also explained based on the previous works of researchers. Tigernut can also be eaten raw, processed in to flour and be used for different purposes such as bread and substitute in animal feed manufacture. Oil can also be obtained from tigernut, which is highly unsaturated and good for the health of humans. Tigernut can be used to produce drink/milk, which can serve as substitute of traditional cow milk, different types of tigernut milk are also produced, it can also be used to produce a local snack “Dakuwa”. Tigernut also contributes to the reduction of cholesterol, it reduces the risk of coronary heart disease, arteriosclerosis and is recommended for those who have heavy digestion, flatulence and dysentery.Keywords: Tigernut, Composition, Milk, Flour, Oil
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Comparison between Antioxidant Activities of Phenolic Extracts from Different Parts of Peanut
Article
  • Jun 2012
Peanut hull and skin are waste products of the food industry. Adding value to these products was the aim of this work. This goal was achieved by studying the phenolic content of the skin, hull and defatted flour of both roasted and unroasted peanuts. The antioxidant activity of the phenolic extracts was determined. The roasted peanut skin extract was then chosen and tested for its power of inhibition of flaxseed oil oxidation. The anticarcinogenic activity of the roasted peanut skin extract on different cell line carcinomas was examined. Both the extractable polyphenols (EPP) and the non extractable polyphenols (NEPP) were determined in the examined parts of the peanuts. Results revealed that NEPP was always higher than EPP and that highest phenolic content was found to be present in the skin. Roasted hull, unroasted hull, roasted skin, unroasted skin, roasted defatted flour, and unroasted defatted flour contained EPP 4.33, 3.38, 41.5, 56.2, 7.33 and 7.23 mg/g, respectively; and contained NEPP 7.4, 5.3, 102, 113.38, 10.3, and 13.4 mg/g, respectively; they also contain total polyphenol extract (TPE) 11.69, 8.73, 144.37, 169.19, 17.48, and 21.31 mg/g, respectively. Free radical scavenging activity (FRSA%) at 100μl conc. reached 87.0 % for roasted and unroasted peanut skin, ca. 79% for roasted and unroasted peanut hull, and least between 45.51- 60.45% for unroasted and roasted defatted peanut flour, respectively. FRSA of BHT (0.1%) was 77.81%. Antioxidant activity (AOA) as measured by β-carotene/ linoleate method revealed AOA for roasted skin > unroasted skin > roasted hull > BHT > unroasted hull > unroasted defatted flour > roasted defatted flour, with values 89.13 > 86.65 > 80.33 > 76.33 > 75.27 > 39.34 > 30.37%, respectively. Roasted peanut skin extract (PSE) was chosen for further investigation. Percent reduction of oxidation in flaxseed oil when compared to control oil reached 27.10% and 22% for oil + PSE, and oil + BHT, respectively, as measured by p-anisidine value; and 41.99% and 38.88%, respectively, as measured by peroxide value. PSE exhibited potential as an anticarcinogenic agent, but needs further investigations.
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Antioxidant capacities, total phenolics and flavonoids in black and yellow soybeans fermented by Bacillus subtilis: A comparative study of Thai fermented soybeans (thua nao)
Article
  • Jan 2013
B. subtilis TN51 was inoculated in cooked black and yellow soybeans, after incubating at 42°C and 4°C for 48 h, the fermented thua nao were produced. The antioxidant capacities, total pehenolics and flavonoids of the fermented black (TN-BS) and yellow (TN-YS) soybeans were then examined as compared to their cooked non-fermented (CNF) soybeans. It was found that fermentation enhanced the increase of total phenolic and flavonoid contents (except yellow soybean fermentation) as well as antioxidant activities of anti-DPPH radicals and ferric reducing antioxidant power (FRAP) of the soybean extracts. The extracts of CNF black soybean and TN-BS, showed higher total phenolic content, total flavonoids, anti-DPPH radicals and lipid peroxidation inhibition than those of yellow soybean extracts. While, FRAP value was found higher in the extract of TN-YS than that in TN-BS extract. Correlation studies indicated significant (P ≤ 0.01) positive correlation between the total phenolic contents and the values of FRAP in soybean extracts (r = 0.889). Whereas, the contents of total phenolics (r = -0.731) and flavonoids (r = -0.709) were negatively correlated (P ≤ 0.01) with IC50 of DPPH radical-scavenging activity. Also, a significant negative correlation (P ≤ 0.01, r = -7.39) was demonstrated between the total flavonoid contents and IC50 of lipid peroxidation inhibition. These results show that black soybean thua nao produced by powder culture B. subtilis TN51 could be used for possible commercial production of functional food to alleviate oxidative stress.
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