Stinky tofu as a rich source of bioavailable S-equol in Asian diets

The compound S-equol (4′,7-dihydroxy-isoflavandiol), a gut bacterial metabolite of isoflavone daidzein, benefits health, but only 20–60% of humans can produce equol after ingesting isoflavones, and it exists only in foods of animal origin in trace amounts. A recent study found a source of stinky tofu contained S-equol. As stinky tofu is a popular traditional fermented soy food in Taiwan, we analyzed S-equol contents of commercial samples, surveyed the intake frequency, and investigated the bioavailability of S-equol by monitoring urinary kinetics following ingestion. Our results showed 91% of the 138 stinky tofu dishes contained S-equol. The mean content per serving (average 198 g) was 2.3 ± 2.5 mg, the highest being 16.3 mg. Stinky tofu eaters on average ingested this food 3.3 times per month. S-equol from ingested stinky tofu appeared in urine within 1 h, reaching maximum excretion at 3.4 h, and 67% of the ingested S-equol was recovered in urine, indicating a rapid and high absorption. Our studies suggest stinky tofu can be a promising dietary source of S-equol for its high content and bioavailability. Further study on the S-equol producing bacteria in stinky tofu is merited for the development of other S-equol rich soy products.     

Nutritional Composition and Antimicrobial Properties of Three Nigerian Condiments

Three Nigerian condiments were analyzed. Dried Irvingia gabonensis seeds and freshly fermented Parkia biglobosa and Prosopis africana were analyzed for their proximate composition, mineral contents and antimicrobial properties. The condiments were found to be very rich in protein (21.35 – 26.13%) with high energy values (351.13–595.05 kcal/ kg). The moisture content of P. biglobosa and P. africana were very high (20.30 – 27.01%) compared to that of Irvingia gabonensis (3.75%) which, however, had a higher fat content (55.09%). I. gabonensis also had higher content of macro elements while P. africana was superior in micro elements. The extracts had higher anti-fungi activities but lower antibacterial activities. The activity index increased with the polarity of solvent of extraction, methanolic extract being the most potent with the highest inhibition activities between 22 ± 1 and 27 ± 1 for fermented P. biglobossa.     

A Critical Evaluation of Survey Results of Vitamin A and Fe Levels in the Mandatory Fortified Food Vehicles and Some Selected Processed Foods in Nigeria

A nationwide survey was conducted to ascertain the levels of Vitamin A and Fe in wheat and maize flours, sugar and vegetable oils and some flour-based processed foods to assess compliance to the Nigerian Industrial Standard. Samples were collected from factories and markets in all the 36 states of the six geopolitical zones of the country; comprising 94 (vegetable oil), 42 (sugar), 95 (flour) and 62 (processed foods) and subjected to vitamin A and iron analyses using HPLC and AAS respectively. Using a 50% acceptable range of the specified minimum standards as basis for compliance, the results showed that only 14.9 – 20.2 % of the samples of vegetable oils analyzed fell within acceptable level (10,000-20,000 IU/kg) but there was no significant difference (p > 0.05) in the results obtained for the six zones. For sugar, only 11.9 – 16.7 % of the samples collected complied with the acceptable range of the standards (12,500 – 25,000 IU/kg) but this varied significantly (p > 0.05) with the zones. The levels of compliance for vitamin A and Fe in flours were found to be 12.2 – 33.3 % and 1.0 – 21.0 % respectively at the acceptable range of 15,000 – 30,000 IU/kg and 34.6 – 46.8 mg/kg, respectively. In all cases, the compliance levels at the 50% range were only marginally higher than at the 30% WHO acceptable range. For the levels of these micronutrients in the processed foods, the values obtained ranged between 5,139 – 7,687 IU/kg for vitamin A and 11.9 – 16.7 mg/kg for Fe. These results call for a critical and holistic review of the fortification strategy in Nigeria.     

Citharexylum solanaceum fruit extracts: Profiles of phenolic compounds and carotenoids and their relation with ROS and RNS scavenging capacities

Citharexylum solanaceum is a native fruit from Brazil, which both bioactive compounds and antioxidant potential were not yet investigated. Thus, the freeze-dried extracts of seed and pulp + skin of C. solanaceum fruits were obtained after solid-liquid extraction with ethanol and their bioactive compounds composition, namely phenolic compounds and carotenoids, were determined. The antioxidant capacity of both extracts against physiologically relevant reactive oxygen species (ROS) and reactive nitrogen species (RNS) was further investigated. Both C. solanaceum extracts showed high contents of phenolic compounds; however, pulp + skin extract presented 2.4-times more phenolic compounds (33.54 mg/g) than the seed extract (14.09 mg/g). Verbascoside (phenylpropanoid) was the major compound identified in both extracts (11–25 mg/g). Regarding the carotenoid composition, all-trans-lutein (14–42 μg/g) and all-trans-β-carotene (13–44 μg/g) were the major compounds in both extracts. The high content of phenolic compounds and carotenoids in pulp + skin extract might explain its higher scavenging capacity against all the ROS/RNS as compared to seed extract. In general, both extracts showed better scavenging capacity for the RNS than for the ROS. Our results indicate that C. solanaceum fruits can be explored as an important natural source of antioxidant compounds.     

Development and Quality Evaluation of a Non-Alcoholic Beverage from Cocoyam (Xanthosoma sagittifolium and Colocasia esculenta)

Cocoyam tubers were processed into non-alcoholic beverage, flavoured with 0.5% and 1.0% extracts of ginger and alligator pepper respectively. Two varieties of cocoyam, namely Colocasia esculenta and Xanthosoma sagittifolium were used. The purpose of this study is to develop an acceptable flavoured non alcoholic beverage from cocoyam and thereby increase the utilization of this under-utilized crop. The proximate, vitamins C and A, mineral content, microbial and sensory evaluation were conducted on the products to assess the highest preference. Values for pH ranged from 3.00 to 3.86 and the total titratable acidity (TTA) from 0.50 – 0.82 with ginger flavoured samples rated higher than that of alligator pepper. Total solids varied significantly and ranged from 5.00 – 6.02% with alligator pepper samples being higher than ginger. Vitamin C content ranged from 1.02 – 1.98 × 10⁻⁴ mg/100 g while vitamin A content ranged from 6.04 to 14.41 μg/100 g with ginger flavoured samples having higher vitamin C and A than the alligator flavoured ones. The minerals evaluated showed a decreasing trends with increase in the concentration of each spice. The sensory results showed that significant differences (p < 0.05) existed between the different flavoured samples and not between varieties. The microbial analysis showed that the cocoyam non-alcoholic beverage is safe for human consumption. Generally, the beverage had good consumer preference with the 0.5% ginger flavoured being the most preferred.     

Quality Evaluation of Maize Chips (Kokoro) Fortified with Cowpea Flour

Quality evaluation of “kokoro” fortified with cowpea flour (0, 10, 20, 30, and 40 %) was studied. The blends were reconstituted into a thick paste, manually moulded into kokoro stick and deep fried in hot vegetable oil at about 170°C for 5 minutes. These flour blends were analyzed for pasting, proximate and functional properties. The result showed that there was significant difference (p < 0.05) in the proximate composition in all the bends. The protein content ranged from 15.20 – 23.03% while ash content was between 1.29 – 1.90%, which increased with increase in cowpea flour. The carbohydrate, fat and fiber contents decreased with values ranging from 59.17 – 65.00%, 3.24 – 4.40% and 2.23 – 2.96%, respectively. The pasting characteristics of the maize cowpea blends gave a peak viscosity ranging from 510 – 702 cp. There was no significant difference (p > 0.05) in the pasting time and temperature. The functional properties reflected that water absorption, oil absorption and foaming capacity significantly increased with increase in cowpea flour with their values ranging from 186.67 – 210.00 g/100 g, 163.33 – 195.00 g/mg and 30.73 – 39.27% respectively. Bulk density also followed the same trend. Sample CAF (100% maize) reflected the highest dispersibility value (6.63%). No significant difference (p > 0.05) was observed in the swelling capacity and least gelatinization concentration. Although the sensory result indicated that increase in cowpea flour does not show a significant difference (p > 0.05) in the sensory parameters, the overall acceptability of the samples was highly rated.     

Effect of Soaking Period on the Ogi Powder Produced from Sorghum

Based on previous research works, it was necessary to investigate the effects of varying steeping period on the quality of ogi powder. Sorghum grain steeped for 24, 36, 48, 60 and 72 h was processed into ogi making use of the traditional method and subsequently dried at 55 °C. The ogi powder obtained was analyzed for proximate composition, functional and pasting properties and consumer acceptability was also carried out. The results showed that the loose and pack bulk density ranged from 0.27 – 0.31 g/ml and 0.53 – 0.55 g/ml respectively from all the steeping periods. Water absorption capacity was from 178 – 199 g/100 g. Linear relationship described well the increase in water and oil absorption in this study and the coefficient of correlation (R²) was 0.988 and 0.814 respectively. Emulsion capacity increased from 19.40 – 21.25 g/100 g for all the steeping periods emulsion stability increased from 6.50 – 6.70%. Foaming capacity decreased from 15.05 – 13.10% for all the soaking periods. Swelling index was between 6.9 – 7.2 per cent for all the steeping periods 5.05 – 5.51 min respectively. There was significant difference (p < 0.05) in the peak viscosity, final, trough, and set back viscosities. These pasting properties decreased with increase in soaking period.     

Proximate and Cholesterol Composition of Selected Fast Foods Sold in Nigeria

Fast foods consumption has been on the increase in Nigeria raising concerns about the nutritional and health implications. This study was carried out to determine the proximate composition and cholesterol contents of four commonly consumed fast foods (doughnut, chicken pie, roasted chicken, and Jollof rice) sold in Nigeria. Commonly consumed fast foods and most widely patronized fast food outlets were determined by a preliminary survey. There was a wide variation in the proximate composition and cholesterol contents of the food samples. Average dry matter ranged between 68.8 – 84.0 g while the range of values for ash, crude fibre, crude fat, crude protein and nitrogen free extract were 0.89 – 2.45%, 0.56 – 7.53%, 10.99 – 18.52%, 1.81 – 9.71% and 43.32 – 66.98% respectively. Energy content of the fast foods ranged between 304.9 and 400.8 Kcal/100 g. Cholesterol levels ranged between 10.40 – 117.80 (mg/100 g) in the food samples. This study has established the fact that fast foods are concentrated sources of energy, low fibre and high dietary cholesterol and could significantly contribute to dietary cholesterol intake with implications for cardiovascular health.     

Structural,thermal and viscoelastic characteristics of starches separated from normal,sugary and waxy maize

Starches separated from five types of maize (two normal, one sugary and two waxy) were investigated for physicochemical, thermal, amylopectin structure and viscoelastic properties. Kisan and Paras were normal maize while Parbhat and LM-6 were waxy maize type. Apparent amylose content of normal and sugary maize was 29.5–32.6 and 41.0%, respectively. Swelling power of normal, sugary and waxy maize starches was 11.6–15.2, 7.8 and 30.2–39.2 (g/g), respectively. X-ray diffraction of maize starches indicated typical A-pattern. Maize starch showed a single broad peak at 2θ=23.2° and a dual peak 2θ=17°–18.1, respectively. Waxy maize starches showed the presence of greater crystallinity than other starches while sugary maize starch showed the presence of lower crystallinity and a large amount of amylose–lipid complex. Intrinsic viscosity [η] of starches in 90% DMSO at 25 °C was 79.7–119.5 ml g⁻¹ for normal, 70.5 ml g⁻¹ for sugary and 107.2–118.1 ml g⁻¹ for waxy starches. Branch chain–length distribution of amylopectin revealed that the apparent amylose, long side chain- and short side chain-amylopectin proportion ranged between 0.0–41%, 13.4–31.5% and 41.5–66.8%, respectively, among the various maize starches. Maize sugary showed the highest apparent amylose content and the least amount of short- and long-side chains of amylopectin. LM-6 and Parbhat showed higher proportion of both long- and short-chain amylopectin as compared to other starches. Distribution of α-1, 4-chains of amylopectin (short-/long-chain) ranged between 2.1 and 3.4, the least for LM-6 and the highest for Paras starch. The transition temperatures (T_o–T_c) ranged between 60.5 and 76.1 °C for sugary, 63.5–76.3 °C for normal and 64.4–81.3 °C for waxy maize starch. The enthalpy of gelatinization (ΔH_gel) of sugary, normal and waxy maize starches was 2.47, 3.7–4.75 and 4.15–5.4 J/g, respectively. Normal and sugary maize starches showed higher G′ and G″ than waxy type starches. The change in the moduli during cooling and reheating of pastes cooked at different temperatures revealed low disintegration of granular structure in starch with higher amylose and amylose–lipid complex as well as low crystallinity. The changes in moduli during 10 h at 10 °C revealed highest retrogradation in maize sugary followed by Paras and Kisan starch.     

Inhibitory effect of polyphenol-rich extracts of jute leaf (Corchorus olitorius) on key enzyme linked to type 2 diabetes (α-amylase and α-glucosidase) and hypertension (angiotensin I converting) in vitro

Corchorus olitorius leaf is consumed in various parts of the world as leafy vegetable and folk remedy for the management of some degenerative diseases with dearth of information on its biochemical rationale. Therefore, this study sought to characterize the inhibitory action of polyphenol-rich extracts (free and bound) of C. olitorius on α-amylase, α-glucosidase and angiotensin I converting enzyme (ACE), as well as to identify the phenolic compound responsible for these activities. Our findings revealed that the extracts inhibited α-amylase and α-glucosidase (12.5–50.0 μg/mL), and ACE (10.0–50.0 μg/mL) in dose-dependently with free extracts having significantly (P < 0.05) higher α-amylase (17.5 μg/mL), α-glucosidase (11.4 μg/mL) and ACE (15.7 μg/mL) inhibitory activities as revealed by the IC₅₀. Reversed-phase HPLC analysis of the extracts revealed chlorogenic acid (7.5 mg/100 g) and isorhamnetin (51.1 mg/100 g) as the main phenolics in the free extract and caffeic acid (58.1 mg/100 g) in the bound extract. Therefore, the enzyme inhibitory activity of C. olitorius extracts may be attributed to the presence of caffeic acid, chlorogenic acid and isorhamnetin, thus justifying its use in folklore for the management of diabetes and hypertension.     

Evaluation and improvement of antioxidant and antibacterial activities of supercritical extracts from clove buds

For the first time, extracts from clove buds obtained by supercritical carbon dioxide extraction were screened for antioxidant and antibacterial activities. Additionally, antioxidant and antibacterial activities of extracts obtained by the supercritical extraction of the clove bud–oregano leaf mixtures were studied. Supercritical extract of pure clove had the highest eugenol (64%) and total phenolic content (530.56 mg GAE/g_extract). All extracts had antioxidant activity comparable to synthetic antioxidants against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and formation of peroxides. Presence of 0.6% and 5% of oregano extract in the clove extracts obtained from the clove–oregano plant mixtures improved their antioxidant activity with respect to the extract from pure clove. Clove extract showed moderate antibacterial activities against selected Staphylococcus and Enterococcus bacterial strains. Presence of 50% of the oregano extract improved antibacterial activity of clove extract against all tested strains and resulted in a synergistic antibacterial activity against Methicillin-resistant Staphylococcus haemolyticus strain (MIC ? 1.25 μg/mL). Study demonstrated great potential of supercritical clove extract as natural functional ingredient and the possibility of increasing its antioxidant and antibacterial efficiencies in order to apply lower concentrations and to reduce undesirable flavour notes and toxicological effects in final products.     

Applicability of extracts from Centaurea calcitrapa in ripening of bovine cheese

Aqueous extracts obtained from cell suspension cultures of Centaurea calcitrapa were used as proteolytic additive in the manufacture of a commercial bovine cheese, coagulated with animal rennet and typically ripened for 28 d. The cheese was assessed in comparison to standard cheese for two levels of addition of said extract, viz. 0.61 and 1.22 mg of total protein mL⁻¹. The qualitative and quantitative evolutions of the nitrogen fractions were monitored in the experimental cheeses throughout the whole ripening period. In general, the chemical compositions of the cheeses were different depending on the amount of extract used, but no significant differences could be detected in the ripening index. With regard to electrophoretic profiles, the two types of cheese could be distinguished until up to ca. 7 d of ripening, but differences did essentially vanish by 28 d.     

Pods of Khejri (Prosopis cineraria) consumed as a vegetable showed functional food properties

The arid plant Prosopis cineraria (Fabaceae) is known as Khejri in India or the golden tree of Indian deserts. The dried pods are consumed as a vegetable and leaves as traditional medicine to cure a wide range of diseases in the state of Rajasthan, India. The pods of this plant have not been investigated for their bioactive components, hence we have done so in this study. The dried pods were boiled with water to afford the aqueous extract. Extraction of the residue gave methanolic extract. The lipid peroxidation (LPO) and cyclooxygenase enzymes (COX-1 and -2) inhibitory activities of extracts and major compounds present in the bioactive extracts were then determined. Purification of bioactive extracts yielded compounds 1–7. The absorbance of 1–7 at 570 nm ranged between 0.15 and 0.45 at 50 μg/mL whereas vitamin C and tert-butylhydroquinone (TBHQ) at 25 μg/mL gave an absorbance of 0.5 in the MTT [3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide] assay. At 25 μg/mL concentration, compounds 1–7 inhibited LPO, COX-1 and -2 enzymes between the ranges of 15–87%, 21–67% and 16–59%, respectively. This is the first report of the chemical and biological activities of the edible part of this plant.     

Antiangiogenic properties of carotenoids: A potential role of maize as functional food

Several human disorders are associated with neovascularization. The current in vivo study examines the effect in the blood vessel formation of a xanthophyll-rich seed extract of maize. The angiostatic effects of treatment with maize seed carotenoid extract (0.1–10 μM of zeaxanthin equivalent/implant) were evaluated in the chick yolk sac membrane (YSM) (12–50% inhibition, P < 0.05) as well as in the chorioallantoic membrane (CAM) assay (23–52% inhibition, P < 0.05) as compared to control group. A similar inhibitory action was found by treatments with the retinoic acid (10 μM/embryo, 49% and 57% inhibition) and commercial lutein (10 μM/embryo, 65% and 55% inhibition) (positive controls) performed in the YSM and CAM, respectively. Results point to maize seeds as interesting sources of xanthophylls which effectively inhibited the process of vessel formation, suggesting a potential role of such compounds in the prevention of diseases associated with vascular dysfunction.     

Pilosocereus arrabidae (Byles & Rowley) of the Grumari sandbank,RJ, Brazil: Physical,chemical characterizations and antioxidant activities correlated to detection of flavonoids

The fruits of Pilosocereus arrabidae (Cactaceae) is found in the Grumari shoal, located in the Rio de Janeiro state, Brazil and, several studies have already highlighted the importance of consuming its fruits. This work aims to investigate the physical, mineral and physicochemical properties of its fruits as well as to establish the knowledge about their chemical constituents and antioxidant properties. The peel (Pe) and pulp (Pu) extracts were obtained by maceration with the following solvents: hexane (HX), dichloromethane (DCL), ethyl acetate (EAC) and ethanol 70% (ET). The extracts were analyzed by Gas Chromatography coupled to Mass Spectrometry (GC–MS) and, by High Performance Liquid Chromatography (HPLC–DAD and HPLC–MS) for its chemical investigation. For the antioxidant activity investigations the ORAC, DPPH and ferrous ion chelating capacity (FICC) tests were performed. As results, we found higher yields for peels (72%) compared to pulps (28%). By the physical–chemical analyses we point out the fruits as a good source of fiber (pulp: 6.01 mg/100 g; peel: 8.02 mg/100 g). The minerals were analyzed by the method of issuing flames and indicated high levels of selenium (DRI for pulp and peel: 147%) and manganese (DRI pulp: 97.69% and DRI peel: 269.56%). The total flavonoid contents of the fruits performed by HPLC–DAD presented 0.45 μg equiv. in quercetin/mL of peel EAC extract and 0.25 μg equiv. in rutin/mL of pulp EAC extract. The antioxidant activities by the ORAC, FICC and DPPH methods indicated that the ET extracts showed antioxidant activities above the standards adopted for the tests. Among these, we highlight the ET extract of the pulp with EC₅₀ of 17.57 ± 0.27 μg/mL, lower than Ginkgo biloba EGB761® (23.40 ± 0.04 mg/mL). By the FICC test the EAC extract of the peel and pulp showed 70.0% and 53.4% activity, respectively, at 500 mg/mL, higher than the standard quercetin (50.0%). By the HPLC–DAD and HPLC–MS methods there were detected, for the first time on this species, the presence of the following flavonoids on the EAC extracts: quercetin, rutin, catechin, dihydrokaempferol, quercetin 3 or 4′-O-glucoside, kaempferol and isorhamnetin. By the GC–MS analysis there were detected on the DCL extracts saturated fatty acids (palmitic and stearic) and, on the HX extracts, methylated sugars (peel) and menthol (pulp). To sum up, the fruits of P. arrabidae display antioxidant potential correlated to flavonoid presence, and, high levels of selenium, manganese and fibers, characteristics that can promote beneficial effects on human health.     

Production of nutraceutics from chestnut burs by hydrolytic treatment

Chestnut (Castanea sativa) burs (CB) were processed by solvent extraction (with ethanol, toluene–ethanol or n-hexane) and/or isothermal autohydrolysis, and the potential as nutraceutics of the solubilized fractions of dietary fiber and antioxidants was evaluated. Among the studied alternatives, the most suited consisted on ethanol extraction, which yielded 21.0 g gallic acid equivalents (GAE)/100 g ethanolic CB extract, with EC_50,DPPH = 0.38 g/L. Ethanol-extracted CB were treated with water at 120 °C, and the soluble fraction was mixed with ethanol to precipitate 8.8 g soluble fiber/100 g CB, with a Water Retention Capacity of 2.4 g/g and an oil absorption capacity of 23.7 g/g. The mother liquors from the above precipitation stage were concentrated and extracted with ethyl acetate to yield an organic phase containing soluble phenolics with high antioxidant activity (EC_50,DPPH = 0.103 g/L) at a yield of 7 g/100 g CB. When the aqueous phase before the ethyl acetate extraction was treated with sulfuric acid, an additional antioxidant fraction (EC_50,DPPH = 0.395 g/L) was obtained. The properties and characteristics of these extracts produced make them good candidates to be used as active ingredients.     

Phenolic composition,antioxidant and antimicrobial activities of free and bound phenolic extracts of Moringa oleifera seed flour

Phenolic compounds, antioxidant and antibacterial activities of defatted Moringa oleifera seed flour (DMF) were investigated. The total phenolic and flavonoid contents were measured using colorimetric methods. Free phenolic acid and flavonoid profiles were analyzed by high performance liquid chromatography, while antioxidant capacities were evaluated using scavenging assays of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), ferric reducing antioxidant power and total antioxidant capacity. The results showed that extractability of phenolic compounds was significantly higher (p < 0.05) in bound phenolic extract (4173.00 ± 32.22 mg gallic acid equivalents (GAE)/100 g) than in free phenolic extract (780.00 ± 14.2 mg GAE/100 g) and it showed higher antioxidant and antimicrobial activities. The IC₅₀ value for DPPH radical scavenging activity was 0.9 ± 0.05 and 14.9 ± 0.07 mg/mL for bound phenolic and free phenolic extracts, respectively. Bound phenolic extract was more effective (minimum inhibitory concentration (MIC), 0.06–0.157%) than free phenolic extract (MIC, 0.117–0.191%) against tested bacteria. Ten phenolic compounds (gallic acid, p-coumaric acid, ferulic acid, caffeic acid, protocatechuic acid, cinnamic acid, catechin, epicatechin, vanillin and quercetin) were identified and quantified in both extracts. These natural plant phenolics from Moringa seeds could be a good source of antioxidants and antibacterials for food and pharmaceutical industries.     

Antioxidant properties of hot water extracts from Ganoderma tsugae Murrill

Ganoderma tsugae Murrill (Ganodermataceae) were available in the form of mature and baby Ling chih, mycelia and fermentation filtrate. From these four forms, hot water extracts were prepared and their antioxidant properties were studied. Hot water extracts from mature and baby Ling chih showed high antioxidant activities (78.5% and 78.2%) at 20 mg/ml, and had EC₅₀ values of 7.25 and 5.89 mg extract/ml, respectively. EC₅₀ values in reducing power were 1.12, 1.37, 2.48 and 1.41 mg extract/ml, whereas those in scavenging abilities of 1,1-diphenyl-2-picrylhydrazyl radicals were 0.30, 0.40, 0.72 and 5.00 mg extract/ml for Ling chih, baby Ling chih, mycelia and filtrate, respectively. At 20 mg/ml, scavenging abilities on hydroxyl radicals were in the descending order of Ling chih>baby Ling chih>mycelia>filtrate. Total phenols were the major naturally occurring antioxidant components found in hot water extracts and in the range of 40.86–42.34 mg/g. From EC₅₀ values obtained, fruit bodies of G. tsugae (Ling chih and baby Ling chih) were good in antioxidant properties, except for the chelating ability on ferrous ions.     

An Automated Cassava Peeling System for the Enhancement of Food Security in Nigeria

Cassava is second only to sweet potato as the most important starchy root crop of the tropical world. In most parts of the tropics, cassava is grown on small plots. However, in some countries, e.g. Mexico, Brazil and Nigeria, large plantations have been started and interest in mechanization is growing. The degree of mechanization depends on the size of the land and availability of machines for each unit operation involved in cassava processing. However, of all the unit operations involved in cassava processing, cassava peeling remains a serious global challenge to process engineers. An automated cassava peeling machine was thus developed in the Department of Agricultural Engineering, Federal University of Technology, Akure. The design of the machine was based on the development and modification of the peeling tool of previous cassava peeling machines and the peeling principle is by impact. This machine was evaluated using newly harvested improved variety of cassava tuber (TMS 30572) grouped into different sizes: 100 ≤ L < 140, 140 ≤ L < 180, 180 ≤ L < 220, 220 ≤ L < 260, and 260 ≤ L < 300. The speed of the machine varies from 100 – 600 rpm while machine operational parameters such as throughput capacity, peeling efficiency, mechanical damage, quality performance efficiency and peel retention were determined for each size. Results revealed that throughput capacity ranged from 76 – 442 kg/h, peeling efficiency ranged from 50 – 75%, mechanical damage ranged from 12 – 44%, quality performance efficiency ranged from 22 – 66%, and peel retention ranged from 7.2 – 33%. These results show appreciable improvement over manual method and existing machines.     

Suppressive effect of Tetragenococcus halophilus,isolated from fish-nukazuke,on histamine accumulation in salted and fermented fish

Occasionally, quantities higher than 1000 mg/kg of histamine (Hm) accumulate in salted and fermented fish products by the histidine decarboxylase of halophilic lactococci Tetragenococcus sp. In a total of 200 isolates from fish nukazuke (salted and fermented fish with rice bran), 13 strains produced Hm more than 200 μg/ml in 0.5% histidine containing broth, whereas 130 isolates produced absolutely no Hm. Among the strains, 22 strains suppressed the Hm production of the Hm-forming (HmF) strains. Both the HmF and Hm-suppressing (HmS) strains were identified as Tetragenococcus halophilus. To observe the Hm-suppressing effect, a specified quantity of live cells was needed. In the case of 10% NaCl salted sardine, inoculation with 3 log cells/g of a strain HmF-131 resulted in a significant Hm accumulation, 2800 μg/g in 30 days at 20 °C. The increase in Hm was clearly suppressed by 9 log live cells/g of strain HmS-129. These results suggest that HmS-129 can be used as a starter for salted and fermented fish products, enhancing food safety.