Relevance of fermented food products in southwest Nigeria

Samples of extruded high protein weaning foods were produced using blends of peanuts, maize and soybean to achieve the desired level of protein. The extruded products, based on a raw and a preroasteds mix of ingredients, were developed and characterized in terms of the hot paste viscosity characteristics, chemical and nutritional quality, amino acid composition, and storage stability. A comparative evaluation of the extruded products was undertaken in relation to two similar existing products: the traditional roasted maize flour weaning food, and thecommercial version. In general, the extruded products were found to have better nutritional quality as indicated by the high protein content of 16.5–18.7% and quality, and excellent rat growth response. For both types of extruded weaning foods developed, between sixty- and one hundred-fold increases in mean weight gain of test rats were recorded over those eating the traditional sample. Correspondingly, the PER values which were between 2.3 and 2.5, were almost thrice the values obtained for the existing products. Significantly higher feed efficiency ratios were also obtained for the extruded products. Hematological data of test animals showed normal values for white blood cell (WBC) count, red blood cell (RBC) count, hemoglobin (Hb) levels and packed cell volume (PCV) for all the weaning foods studied, except the existing traditional roasted maize flour. In terms of storage stability of the extruded products, predicted shelf life periods of 7.8–10.4 months were obtained for the extruded raw blend, and 5.6–7.1 months for the extruded preroasted blend when stored at the average ambient temperature of about 30,°C in Ghana. In general, the preroasting treatment was found to reduce the quality characteristics of the extruded product.     

Effect of blanching and ripening on functional properties of plantain (Musa aab) flour

Flours were prepared from raw and blanched samples of and ripe mature plantain Musa aab and examined for theirproximate composition, physical characteristics and functionalproperties. The plantain flours contained 3.5 g crude protein,2.5–3.5 g crude fat, 5.7–7.1 g moisture, 1.33–2.0 g crudefiber, 1.66–2.0 g ash, and 82.25–86.07 g carbohydrate per 100 gsample. The flours had bulk densities between 0.42–0.72 g/ml,emulsion capacities of 4.7–14.7%, water absorption capacitiesof 250–338%, oil absorption capacities of 214–371%,foaming capacities of 1.90–5.79%, least gelation concentrationsof 6–8%, and viscosities of 23.7–46.7 CP at 2% slurry concentration. Foaming capacity increased with increasing flourconcentration. Blanching considerably reduced the emulsion capacity and viscosity, while bulk density, water and oilabsorption capacities were increased by blanching. Ripening wasfound to have a negative effect on all the functional propertiesexamined except the bulk density, and gelation property. Unripe plantain could be used as an emulsifier and thickener in a foodsystem.     

Some observations on the toxic effects of the seed extract ofSphenostylis stenocarpa (Hochst ex A. Rich) Harms. on intestinal muscle

The effects of the water extract ofSphenostylis stenocarpa were observed on the guinea pig ileum and rabbit jejunum. The extract produced dose dependent — contractions of the guinea pig ileum with an ED₅₀ of 3.664×10^–5 g/ml and a calculated dose ratio of 1.25. The extract specifically stimulated muscarine receptors. Atropine (8×10^–7 g/ml) caused a parallel shift to the right of the log dose — response curve in the guinea pig ileum suggesting a competitive antagonism. Boiling for about 12 h did not affect the contractile action of the extract on tissue preparations. However, boiling for 12–14 h completely abolished its contractile effect. Incubation of the extract with cholinestrerase at 37°C for 1 h did not abolish its contractile action on the intestine.     

In vitro starch and protein digestibility and iron availability in weaning foods as affected by processing methods

In the present investigation, four weaning foods were formulated using locally available cereals and pulses such as wheat (Triticum aestivum), barley (Hordeum vulgare) and green gram (Vigna radiata). Cereal, pulse and jaggery were used in the proportion of 70:30:25. Domestic processing technique like roasting and malting were used to process cereals and pulses for development of weaning foods. All the four blends had a nutrient composition within the range prescribed by the Indian Standard Institute (ISI) for processed weaning foods. The processing of grains resulted in 16–20% increase in starch digestibility and 17–32% increase in protein digestibility. Also 16–32% increase in iron availability was observed on processing. The effect was more remarkable in malted weaning foods as compared to roasted ones.     

Proximate composition and functional properties of four cultivars of bambara groundnut ( Voandezeia subterranea)

Proximate composition and selected functional properties of four cultivars of bambara groundnut ( Voandezeia subterranea Thoura) were ascertained. Crude protein ranged from 17.5 to 21.1 percent; crude fat 7.3–8.5 percent; total ash 4–5 percent; crude fiber 1.8–2.0 percent; carbohydrate and moisture content for the different cultivars were 53.0–60.8 percent and 7.5–12.3 percent, respectively. The results of functional property determinations indicated that the bulk density ranged from 0.65 to 0.75 g/ml; water binding capacity 2.1–2.9 g/2g sample; oil binding capacity 0.9–1.6 g/2g sample; emulsifying activity 55.-1–60.0 percent and emulsifying stability 10–12 percent. The results show that bambara groundnut has great potential for incorporation into various human foods where it could provide useful plant proteins.     

Quality evaluation of commercial chile-based salsas

A standardized extrusion cooking process was developed for production of a high protein weaning food based on peanuts, maize and soybeans. Major factors evaluated included the effects of blend formulation, extrusion temperature and feed moisture content on ease of extrusion and product quality characteristics. Results showed bulk density and hardness increased while expansion index decreased with increase in feed moisture content. At a fixed range of feed moisture content, product bulk density and firmness decreased while expansion index increased with increasing extrusion temperature. For ease of extrusion and best product quality in terms of sensory attributes and cooking properties, the following extrusion parameters were established for a blend formulation of 75% maize, 10% peanut and 15% soybean: feed particle size of 300–400 m extruded using a screw speed of 500 rpm, with a feed rate of 4.6 kg/min, feed moisture content of 16–18%, and extrusion temperature of 100 ,°C–105,°C. Pair-wise comparison of the sensory attributes of porridges prepared from milled samples of the weaning foods showed significant differences between extruded products and existing traditional counterparts, with very high scores for all sensory attributes of the extruded products, especially extruded raw (non-roasted) blend samples. In the Home-Use-Test, at least 92% of respondents in two out of the three major ecological zones of Ghana placed overall sensory and functional characteristics of extruded raw blend samples as highly acceptable. About 7% of respondents scored sensory and functional quality attributes as acceptable.     

Optimization of the solid state fermentation process to obtain tempeh from hardened chickpeas (Cicer arietinum L.)

Solid state fermentation (SSF) represents a technological alternative for a great variety of cereals and legumes, orcombination of them, to improve their nutritional quality and to obtain edible products with palatable sensorial characteristics. The objective of this work was to find the best conditions of fermentation temperature and time to obtain tempeh from hardened chickpeas (Cicer arietinum L.) applying SSF. Response surface methodology(RSM) was applied over three response variables (phytic acid, in vitro protein digestibility and available lysine) to find best conditions of fermentation to carry out the process. A central composite experimental design with two factors [X₁ = temperature (31–36 ^°C) and X₂ = time (48–72 h)] in five levels (2 factorials,2 axial, I central) was used. Spores from Rhizopus stolonifer were suspended in distilled water (1 ×10⁶ spores/mL) and used as starter. According to regression models, minimum and maximum levels of the response variables were 1.24–2.66 mg phytic acid/g ofsample DM, 77.6–83.5% in vitro protein digestibility and2.18–4.63 g available lysine/16 g N. The superposition ofcontour plots of each one of the response variables allowedresearchers to find, graphically, the best conditions for the SSF process: 35.8 ^°C for 42.7 h.     

Content of antinutrients and in vitro protein digestibility of the African yambean,pigeon and cowpea

The protein, trypsin inhibitor (TI), tannin, phytate, phytic acid phosphorus and in vitro protein digestibility (IVPD) of cultivars of the African yambean (Sphenostylis stenocarpa) — AYB, pigeon pea (Cajanus cajan) — PP and cowpea (Vigna unguiculata) — CP were determined. The protein content of CP (24–28.0%) was higher than those of PP (21–22.5%) and AYB (21–22.5%). The cream and speckled AYB contained more TI (30.9 and 25.3 mg/g) than PP (7.5–14.1 mg/g) and CP (9.8–20.5 mg/g). Apart from the white CP cultivar, they contained more tannin (1.24–1.42 mg/g) than PP (0.14–0.97 mg/g) and AYB (0.71–1.17 mg/g). Phytate was lowest in the AYB (6.30–7.49 mg/g) than PP (8.31–11.31 mg/g) and CP (8.40–9.92 mg/g). Phytic acid contributed 67–74% of the phosphorous in the AYB, 66–75% in PP and 54–59% in CP. The IVPD of the AYB (73.3±0.7%) was significantly lower (p<0.05) than those of PP (76.34±0.2%) and CP (77.8±0.4%). There was a significant negative correlation between TI and IVPD (r=–0.63,p<0.05). There was no significant correlation between IVPD and phytate and tannin contents. There was a positive correlation between protein content and IVPD (r=0.69**) for the legumes under study. These legumes may pose no serious problems to populations consuming them especially when heat treatment is applied before consumption.     

Effect of extrusion process variables on physical and chemical properties of extruded oat products

The purpose of this research was tostudy the effects of initial moisture levels andextrusion temperatures on bulk density, waterabsorption and water solubility indexes, viscosity,and color of extruded oat products. The dehulledgrains were ground in a Brabender Quadrumat Seniormill and the coarse fraction, with higher amounts ofcrude protein, lipids, and dietary fiber content, wereconditioned to moisture levels of 15.5–25.5% andextruded in a Brabender single-screw laboratoryextruder. The water absorption index of extrudateswere relatively low (4.16–6.35 g gel/g sample) butincreased as the initial moisture of the raw materialas well as the extrusion temperature was elevated.The water solubility index was inversely proportionalto the extrusion temperature. Initial viscosity of thepaste increased with the increase of raw materialmoisture and extrusion temperature, while the maximumviscosity (at a constant temperature) diminished withthe increase of temperature. Products with lowervalues of L* (luminosity) and greater values ofa* (red) and b* (yellow) were obtained athigh moisture rates and at a 120 ^°C extrusiontemperature.     

Knowledge,attitude and usage patterns of fermented and germinated complementary foods in Nigeria

A detailed general information questionnaire was used to elicit informationfrom 400 households in two urban and two rural communities each in Anambraand Enugu states in Nigeria. The results showed that over 85% of the samplepopulation in both states were familiar with fermentation as a food processing method. Only 1.01% was familiar with germination as a processingstep in traditional food preparation. Preference (15–54%), cost (4–16%),mother's advice (2–14%) and medical advice (4–5%) in the 4 locationslargely influenced choice of foods. The amount of money spent on complementary foods in surveyed families ranged from less than N 100 (US$1.11) to more than N 400 (US$>4.44) per month. Fermented complementary foods were mostly homemade though some mothers used a variety of commercial complementary foods in addition.In general, 86.5–95% of the mothers interviewed had used fermented foods;13.5% had neither used nor germinated foods. The food most frequently fermented was corn (71.82–86.69%). The period of fermentation varied fromless than 1 day to over 3 days and fermented foods were introduced toinfants from 4–6 months after birth mainly as a cultural practice. Otherreasons for the use of fermented foods varied from improving taste, helpingthe child grow, removing toxins to improving nutrient contents of foods.Fermented foods were stored in buckets covered with water or in a refrigerator. Improved technology in the production of fermented complementary foods will reduce the tedious work involved in processing andimprove quality of foods consumed by children.     

Tempe Consumption Modulates Fecal Secondary Bile Acids, Mucins, Immunoglobulin A, Enzyme Activities, and Cecal Microflora and Organic Acids in Rats

The present study investigated the effect of dietary tempe, a fermented soy product, on the colonic environment of rats fed high-fat (HF, 30 % fat; experiment 1) or low-fat (LF, 6 % fat; experiment 2) diets. Growing male rats were fed the experimental diets with or without 25 % tempe for 21 days. Tempe consumption slightly but significantly increased the growth of rats fed both the HF and LF diets (P?<?0.05). With both the HF and LF diets, dietary tempe markedly reduced a harmful fecal secondary bile acid, lithocholic acid (a risk factor of colon cancer) (P?<?0.05), and markedly elevated fecal mucins (indices of intestinal barrier function) and immunoglobulin A (IgA, an index of intestinal immune function) (P?<?0.05). With the HF diet, dietary tempe increased cecal acetate, butyrate, propionate, and succinate concentrations (P?<?0.05). Analysis of the profile of cecal microflora revealed lower Bacteroides and higher Clostridium cluster XIVa levels in the tempe group of rats fed the HF diet (P?<?0.05). Compared with the control group, the fecal activity of β-glucosidase was markedly higher in the tempe group (P?<?0.05), while that of urease was lower (P?<?0.05) with both the HF and LF diets. The present results suggest that tempe consumption modulates the colonic environment in rats.     

Quality attributes of three new improved lines of Nigerian lima beans (Phaseolus lunatus L. Walp.)

Three promising new improved lines of lima beans (Tpl 1^B, Tpl 7^A and Tpl 175^A) were evaluated for physicochemical properties and cooking quality. The beans varied in seed dimensions and weights with Tpl 1^B and Tpl 7^A having smaller seed volume than Tpl 175^A. Seed coat percentages, leached solids and swelling capacities were within a range of 10.2–19.6% (w/w), 0.44–0.92 g/100 g and 94.0–121.0 g/100 g dry bean, respectively. Cooking times varied between 62 and 81 min without soaking and were reduced by about 34%following a presoaking treatment in water for 12 h at room temperature (28 ± 1 °C). Small seeds absorbed higher amounts of water during soaking and required more cooking time than larger seeds. No significant (p>0.05) difference in cooked texture was found between unsoaked beans cooked for 50 min and soaked beans cooked for 30 min,suggesting that cooking times and cooked texture for all lines were improved through soaking.     

Cassava-soy weaning food: Biological evaluation and effects on rat organs

Weaning food was formulated using a cassava product, `Tapioca' (TAP), supplemented with roasted – sproutedsoybeans (SS), with and without additional (10%)malted sorghum flour (MS). Biological evaluation wascarried out on the formulations using 4–5 week oldweanling albino rats, with Cerelac (a commercialmaize-milk weaning food) as the control diet. Therewere increases in growth rate of rats fed with boththe test and control diets. There were no significant(p > 0.05) differences between the test diets andcontrol diet in true digestibility values. Thebiological value (BV) and net protein utilization(NPU) values for the formulated diets were above therecommended minimum values. The weight of organs(small intestine, pancreas, liver and heart) of ratsfed TAP + SS and TAP + SS + MS based diets were nothigher than those of organs of rats fed Cerelac. Itwas concluded that cassava products could potentiallybe employed successfully in the preparation of weaningfoods of comparable quality to available commercialbrands.     

Nutritional quality of germinated cowpea flour (Vigna unguiculata) and its application in home prepared powdered weaning foods

Amino acid profiles, protein digestibility corrected aminoacid scores (PDCAAS), chemical scores, essential amino acid indexes, andcalculated biological values of control-cowpea flour (CCF), germinated cowpeaflour (GCF) prepared from cowpeas germinated at 25 ^°C for either24 h or 48 h and weaning foods prepared from cowpea flours weredetermined. Locally available rice, cowpea flour, banana-pumpkin slurry,and skim milk powder and sucrose in the ratio 35:35:15:15:5 were used to formulateweaning food containing not less than 15% protein. The ingredients werecooked into a slurry and oven-dried to produce flakes. The nutritional andsensory qualities of the weaning products were evaluated. Germination hadlittle effect on the amino acid profile of cowpeas. In vitro proteinquality and starch digestibility were improved in germinated cowpea flour. The PDCAAS of 24 h germinated cowpea flour (GCF) weaning food washigher (55.49%) than CCF-weaning food (46.74%). Vitamin A activityin 24 h GCF weaning food was higher than in CCF-weaning food. Invitro starch digestibilities of 24 h GCF and 48 h GCF-weaning foods werehigher than that of CCF weaning food. The 24 h GCF-weaning food which hada higher overall acceptability score by sensory panelist than 48 h GCFand CCF-weaning food is recommended for household consumption.     

Fatty acid,amino acid,and trace mineral analyses of five weaning foods from Jos,Nigeria

Five plant-based weaning foods (WF) (Dietrend, Jot-M, Soy, Ang and Vic-T) locallyprepared in Jos, Nigeria were analyzed by gas-liquid chromatography,reverse-phase high performance liquid chromatography, and atomicemission spectrometry with inductively coupled plasma to determine theirfatty acid (FA), amino acid, and trace mineral contents, respectively.Results of these direct analyses were compared to expected values derivedfrom food composition tables prepared by the United States Department of Agriculture (USDA). Additionally, results were compared against recommendednutrient values, using breast milk as the standard for FA content andrecommended dietary allowances (RDA) for amino acid and mineral contents.The overall nutritional value of the five WF varied considerably and thequantities of particular nutrients determined by direct analysis differedmarkedly from those estimated using USDA food tables. Comparison of WFfatty acid composition relative to the RDA recommendations and a humanmilk standard revealed a much higher proportion of both linoleic (35–55wt%) and -linolenic acids (1%–7 wt%) relative to human milklipids (11%–12% and 0.8%–0.9% wt, respectively); however, the WFwere devoid of arachidonic acid and docosahexaenoic acid. Soy containedthe highest amounts of linoleic acid (59.7 mg/g) and -linolenicacid (7.46 mg/g) compared to the other four WF (10.2–41.0 and 0.35–3.18 mg/g, respectively). The linoleic acid/-linolenic acid ratio was within the recommended range (5:1 to 10:1) in only Jot-M (10:1)and Soy (8:1). Dietrend, Vic-T and Ang, containedlinoleic/-linolenic ratios of 12:1, 29:1, and 82:1, respectively.The Soy weaning food would provide the most protein (24.3 g/day), basedon an estimated daily intake of 65 g of weaning food by a normalsix-month-old infant, compared to Jot-M (11.9 g/day), Dietrend (11.7g/day), Ang (8.07 g/day) and Vic-T (7.26 g/day). The protein RDA forchildren up to 1 year of age is 13–14 g/day. Comparison of the mineralcontents of the WF to the RDAs for various minerals indicated that all fivewould provide suboptimal amounts of calcium (16 to 250 mg/day) andzinc (1.42 to 3.56 mg/day) compared to respective RDAs of400 mg/day and 5 mg/day.These data show that the Soy weaning food is an excellent source of linoleicacid and -linolenic acid, as well as being a good source of highquality protein. Jot-M and Dietrend provide useful amounts of the essentialFA; however, it is advisable to reevaluate the composition of Ang andVic-T to find ways to improve the linoleic/-linolenic ratio of eachand increase their total protein content. These results document theshortcomings of using published food composition tables based on foods inAmerica when devising weaning foods based on ingredients in another partof the world.     

Interrelationships between certain physical and chemical properties of dry bean (Phaseolus vulgaris L.)

The interrelationships among certain physical and chemical properties of ten cultivars of dry beans (Phaseolus vulgaris L.) were investigated. The length/breadth ratio was similar (1.51–1.65) except for kidney beans (>2.0) and sanilac (1.37) cultivars. The breadth/thickness ratio ranged from 1.17–1.65. The 100-bean weight indicated a wide variation of 15.03–50.33 g. The density, bulk density, and porosity characteristics were within a narrow range of 1.18–1.36 g/cc, 68–75 g/100 cc, and 40.7–48.5%, respectively. Water uptake rates during the first 6 h of soaking at room temperature (21 °C) were characteristic of the cultivar. At the end of 24-h soaking, however, all cultivars had absorbed similar amounts of water (approximately 1 g/g bean). Leaching losses (g solids leached/100 g beans) had characteristic trends and ranged from 0.54 for cranberry to 3.46 for sanilac cultivars after 24-h soaking. Most correlations between selected chemical constituents and physical characteristics of the dry bean were relatively low.Journal Paper No. 2751 of Utah Agricultural Experiment Station and a contribution of Western Regional Project W-150.     

Physical behavior of purified and crude wax obtained from Sunflower (Helianthus annuus) seed oil refineries and seed hulls

The sunflower seed waxes obtained from two sources (i) seed hull as astandard and (ii) crude wax from oil refineries were studied for theircrystallization, melting characteristics and morphology of crystals. Theresults of differential scanning calorimetry of wax obtained from seed hullsshowed the melting temperature range of 13.18 ^°C with the onsetat 62.32 ^°C, for purified wax, compared to the melting range of24.73 ^°C with the onset at 42.3 ^°C, for crude wax. Theenthalpy of fusion for both waxes were 57.55 mcal/mg and 7.63 mcal/mg,respectively. The DSC melt crystallization temperature range was15.79 ^°C with the onset of 64.58 ^°C for purified wax andtemperature range of 31.45 ^°C with an onset of 57.76 ^°C forcrude wax. A similar pattern was observed of wax obtained from thecrude wax of oil refineries. The enthalpy of crystallization was –64.27mcal/mg and –7.67 mcal/mg, respectively. The purified wax obtained fromthe two sources (i) and (ii) were comparable with completion temperaturesof 75.5 ^°C and 75.1 ^°C, respectively. The effect of inhibitor(lecithin) on crystallization of purified wax under light microscope andsurface structure by scanning electron microscope were observed. Lecithinat 0.2% inhibited the crystallization but nucleation was unaltered. Thewax crystal was inhibited to around 60% of the original size with 0.2%lecithin. It is concluded that the sunflower waxes studied were notcomparable in their crystal properties of crude and purified states.Lecithin inhibited the crystallization of sunflower seed wax.     

Effect of process improvement on the physico-chemical properties of infant weaning food from fermented composite blends of cereal and soybeans

Saccharomyces cerevisiae and Lactobacillusplantarum ATCC 10776 were used as starters toferment various composite blends of cereals and legumes produced through malting and toasting of two varieties of maize – Zea mays (DMR-LSR white & DMR-ESR yellow),sorghum – Sorghum bicolor (Dawa white & Dawared) and one variety of soybeans (Glycine max). Compared to the untoasted and unmaltedfermented blends, a relatively lower pH (3.6),highly sour product was obtained with 12 h offermentation. Results also showed that cereal and soybeantoasting brought about a better reconstitution indices(B25, 84 ml; B45, 87 ml), water holding capacities(B25, 0.68 ml/g; B45, 0.62 ml/g), bulk densities (C15,11.6; C35, 10.8) and gross energy (B15, 501.5Kcal/100g; B45, 508.5 kcal/100g) at the end offermentation. Furthermore, reductions in totalpolyphenol and tannin contents were observedwith fermentation of toasted and malted cereal blendssupplemented with toasted and malted soybeans whileporridges from the same blends displayed desirablestarch stability and consistent gelling tendency,although B15 (a ferment of malted, toasted white maizesupplemented with toasted and malted soybean) fellwithin acceptable limits. In all, the physicalcharacteristics were affected by varieties of cerealand soybeans.     

Alpha-amylase inhibitor changes during processing of sweet potato and taro tubers

Alpha-amylase inhibitor changes during processing ofsweet potatoes (Ipomoea batatas) and taro (Colocasia esculenta)indicated that varietal differences profoundly influence the thermalinactivation profile. The -amylase inhibitors of taro were almosttotally inactivated during oven drying of the chips at 90 ^°C and100 ^°C for 24h, while 0.8–10% activity was retained in sweetpotato chips under the same conditions. Relatively better thermal stabilitywas exhibited by the sweet potato amylase inhibitors at lower temperatures(70 and 80 ^deg;C) as well. Cooking by boiling the tuber pieces inwater resulted in retention of 29–59% amylase inhibitor in sweet potatoand 11–16% in taro. Microwave baking was a better method forinactivation of amylase inhibitors in these tubers. Flour prepared from thetubers retained only trivial amounts of the inhibitor.     

Control of Penicillium expansum with potassium phosphite and heat treatment

Potassium phosphite (Phi) was evaluated for its in vitro activity against Penicillium expansum and for its potential long-term efficacy against postharvest blue mold infections on apple fruit. Phi amended to malt extract agar medium at 2 and 4 mg/ml completely inhibited mycelial growth and conidial germination, respectively. Conidia of P. expansum suspended for 3 min in a solution of 2 mg/ml Phi at 20 °C or heated to 50 °C germinated at 53 and 0%, respectively. Disease incidence of P. expansum on Elstar apples wounded and inoculated with a thiabendazole-resistant isolate was reduced significantly (P = 0.01) following a curative treatment with Phi at 2 mg/ml. When applied on freshly harvested unwounded Elstar apples, Phi (2 mg/ml) reduced blue mold incidence about three-fold compared to the control and was found to be as effective as thiabendazole against natural blue mold infections after six months of storage at 2 °C. Our results suggest that potassium phosphite has a potential to be part of the general management program implemented for the control of postharvest blue mold infections on pome fruits.