Physical,Sensory and Microbiological Properties of Wheat-Fermented Unripe Plantain Flour

The physical, sensory and microbiological properties of wheat-fermented unripe plantain composite flour bread were studied. Mature unripe plantain was peeled, sliced, steam blanched, dried and milled into flour. The flour was made into a slurry (10 g of flour/3 ml of water) and allowed to ferment for 24 h. It was then dried, pounded and sieved through 0.25 mm sieve. The fermented unripe plantain flour was then blended with wheat flour in the ratios of (wheat:fermented unripe plantain) 100:0; 90:10; 80:20; 70:30; and 60:40. Bread was produced from the flour blends using the straight dough method. Loaf weight and volume decreased significantly (p < 0.05) with increasing levels of plantain flour inclusion. Sensory evaluation of the flour samples revealed significant differences in the ratings for crumb colour and texture between 100% wheat flour (100:0) and 60% wheat-40% fermented unripe plantain flour (60:40) bread but no significant difference was observed between all bread samples with respect to crust colour, taste, aroma and overall acceptability. The sensory scores showed that all the bread samples were acceptable. Microbiological analysis (total viable count) revealed that all the bread samples were free of microorganisms for up to four days after production.     

Bread Making Potential of Composite Flour of Wheat-Acha (Digitaria exilis staph) Enriched with Cowpea (Vigna unguiculata L. walp) Flour

Bread-making potentials of composite flours containing 90% wheat and 10% acha enriched with 0-15% cowpea flour were investigated. Proximate composition and functional properties of the blends were studied using AOAC standard methods. Bread loaves were prepared from the blends using the straight dough method and evaluated for loaf height, loaf volume, loaf weight and sensory characteristics. Crude protein, crude fat, crude fibre and ash contents increased significantly (p < 0.05) with increase in level of cowpea flour addition, but moisture content was not significantly (p > 0.05) different among the blends. Functional properties, with exception of bulk density and swelling capacity, were significantly (p < 0.05) different among the blends. Average loaf height and loaf volume decreased significantly (p < 0.05) with increased cowpea flour but loaf weight showed opposite trend with significant (p < 0.05) differences as cowpea flour increased. However, the addition of cowpea flour significantly (p < 0.05) decreased the loaf specific volume but all enriched samples were not significantly (p > 0.05) different. Bread samples from composited blends were rated lower than bread from all wheat bread. Bread loaves from enriched composite flour with up to 10% cowpea flour were acceptable to the panelists.     

Enrichment of Noodles with Soy Flour and Carrot Powder

Noodles were produced from four flour blends of whole wheat, wheat-cassava, wheat-cassava-soy flour and wheat-cassava-carrot flour blends respectively. The flours were analyzed for proximate analysis, functional properties and total carotenoid content. The cooking time of all samples was also determined. Results show that there were significant differences (p < 0.05) between values obtained for moisture content, protein and total carbohydrates (p < 0.05) while values for fat and ash contents of the samples were not significantly different (p > 0.05). The functional properties also showed significant differences (p < 0.05) between the pasting properties except for pasting temperature and the cooking time of the samples. The total carotenoid content of the dried carrot sample was found to be 28.34 mg/100 g dry weight basis, while the noodle sample containing 10% dried carrot sample (CSC4) had a total carotenoid content of 1.80 mg/100 g dry weight basis. The results suggest that noodles made from the different flour blends can compare favourably with conventional noodles made from wheat flour in quality and that carrot flour can be used for noodle enrichment.     

A comparison of the ability of several small and large deformation rheological measurements of wheat dough to predict baking behaviour

The rheological characteristics of twenty wheat flour samples obtained from four organic flour blends and a non-organic control were compared in relation to their ability to predict subsequent loaf volume in the baked bread. The flour samples considered had protein contents that varied between 11–14 g/100 g. Four different rheological methods were employed. Oscillatory stress rheometry on the protein gel extracted from the wheat flour, oscillatory stress rheometry and creep measurement on undeveloped dough samples and biaxial extensional measurements on simple flour–water doughs. None of the fundamental rheological parameters correlated with loaf volume. There was a correlation between the storage modulus of the gel protein and storage modulus for the undeveloped dough (r = 0.85). There was a weak negative correlation between protein content and biaxial extensional viscosity (r = −0.62). Stepwise multiple regression related loaf volume to dough stability time (measured on the Farinograph) and tan (phase angle) for the undeveloped dough samples (overall model r² = 0.54). The results indicate that the four rheological tests considered could not be used as predictors of subsequent loaf volume when the bread is baked.     

Effects of Defatted Jack Bean Flour and Jack Bean Protein Concentrate on Physicochemical and Sensory Properties of Bread

This study evaluated the effects of substituting wheat flour with defatted Jack bean flour and Jack bean protein concentrate on bread quality. Jack bean flour milled from the seed nibs was defatted with n-hexane and part of the defatted flour (DJF) extracted in acid medium (pH; 4.5) for protein concentrate (JPC). Both the DJF and JPC were analysed for nutrient composition, and then used to fortify bread. Five bread samples with 0%, 10% and 20% of DJF or JPC were prepared using straight dough procedure, and then analysed for quality characteristics. The DJF and JPC had 28.8% and 49.47% protein, 46.44% and 30.22% carbohydrate, 0.61% and 1.00% crude fibre respectively; and were rich in Ca, Fe, Zn and P. Both DJF and JPC improved quality of bread but JPC conferred better quality. The 20% DJF and JPC respectively improved protein content of bread from 9.45% to 10. 97% and 11.16%, crude fibre from 2.39% to 5.20% and 5.32%, fat from 2.35% to 7.00% and 6.55%, and ash content from 1.35% to 2.05% and 2.10% but decreased carbohydrate content from 72.12% to 50.45% and 50.39% in the bread samples. All the fortified bread samples had acceptable crumb colour, crumb texture, flavour and loaf volume significantly comparable (p > 0.05) to those of 100% wheat bread. Thus, defatted Jack bean flour and Jack bean protein concentrate is recommended for use in fortifying bread for higher quality.     

Effect of Honey as Partial Sugar Substitute on Pasting Properties,Consumer Preference and Shelf Stability of Cassava-Wheat Composite Bread

The effect of partial substitution of sugar with liquid honey on the pasting properties of cooked dough made from cassava-wheat composite (10:90) flour as well as the sensory preference and shelf stability of its bread was investigated. Sucrose (S) in the bread recipe formulation was substituted with honey (H) at levels 0, 10, 20, 30, 40 and 50%, respectively to give 6 treatments, namely 0H:100S, 10H:90S, 20H:80S, 30H:70S, 40H:60S and 50H:50S. Amylograph pasting properties of the dried crumbs were determined using standard analytical procedures. Fresh bread samples were subjected to sensory evaluation and fungal count during storage (6 days). Peak, final and setback viscosities of bread crumb decreased (32.29 to 25.33, 58.54 to 43.00 and 30.96 to 23.66 RVU), respectively as the level of honey inclusion increased. Honey substitution levels used did not significantly (p > 0.05) affect aroma and texture of the bread samples but composite bread with 20% level of honey substitution was most preferred in terms of colour while composite bread with 30% level of honey substitution was most acceptable in terms of taste and overall acceptability. Fungal count in stored honey-cassava-wheat bread varied significantly (p < 0.05) from 0.6 to 4.0 × 10², 1.0 to 6.9 × 10², 2.2 to 57.0 × 10², 32.0 to 135.7 × 10², 34.0 to 140.0 × 10² and 42.0 to 159.3 × 10²) cfu/ml from day 1 to day 6, respectively. From the study, it was concluded that substitution of sugar with honey in dough formulations significantly (p < 0.05) affects dough pasting properties, improves acceptability of the composite bread and reduces staling rate.     

Evaluation of viscoelastic properties and air-bubble structure of bread containing gelatinized rice

The impact of addition of gelatinized rice porridge to bread has been investigated on loaf volume, viscoelastic properties and air-bubble structure. We prepared four variety of bread: bread containing rice porridge (rice porridge bread), bread containing gelatinized rice flour (gelatinized rice flour bread), and wheat flour and rice flour breads for references. Instrumental analyses the bread samples were carried out by volume measurement of loaf samples, creep test and digital image analysis of crumb samples. Rice porridge bread showed the maximum specific volume of 4.51 cm³/g, and even gelatinized rice flour bread showed 4.30 cm³/g, which was larger than the reference bread samples (wheat and rice flour breads). The values of viscoelastic moduli of gelatinized rice flour bread and rice porridge bread were significantly smaller (p < 0.05) than those of wheat flour and rice flour breads, which indicates addition of gelatinized rice flour or rice porridge to bread dough encouraged breads softer. Bubble parameters such as mean air- bubble area, number of air-bubble, air-bubble area ratio (ratio of bubble area to whole area) were not significantly different among the bread crumb samples. Therefore, the bubble structures of the bread samples seemed to similar, which implied that difference of viscoelasticity was attributed to air-bubble wall (solid phase of bread crumb) rather than air-bubble. This study showed that addition of gelatinized rice to bread dough makes the bread with larger loaf volume and soft texture without additional agents such as gluten.     

Preliminary Studies of the Chemical Composition and Sensory Properties of Sweet Potato Starch-Wheat Flour Blend Noodles

Preliminary studies of chemical composition and sensory properties of instant noodles from blends of wheat flour and sweet potato starch were carried out. Sweet potato starch was used to replace wheat flour at 30, 40, 50, 60 and 70%. Proximate, vitamin A, mineral analysis and sensory evaluation were carried out by standard methods. Results showed that the formulated noodles had higher carbohydrate (63.34 – 70.53%), moisture (4.34 – 4.97%) and vitamin A (11.62 – 35.00 mg/100 g) but lower protein (3.36 – 7.89%), fat (16.91 – 25.09%), calcium (0.73 – 0.89%), phosphorus (0.24 – 0.32%), iron (0.10 – 0.27%) and ash content (1.17 – 3.17%) than the commercial noodles from wheat flour. The noodles containing 30% sweet potato starch showed no significant difference (p > 0.05) from commercial noodles (100% wheat flour) in terms of colour, crunchiness, taste and general acceptability, with improved nutrient composition. It is concluded that production and consumption of wheat flour/potato starch blend noodles should be encouraged to increase the calorie and vitamin A intake in the diet, especially for children who are the major consumers of noodles; apart from helping to promote and improve the utilization of sweet potato tubers.     

Physicochemical and Sensory Properties of Instant Kunun-Zaki Flour Blends from Sorghum and Mango Mesocarp Flours

Instant Kunun-zaki, a fermented non-alcoholic sorghum beverage, was prepared by mixing different per cent blend ratios of unmalted sorghum flour: mango mesocarp flour (90:0, 75:15, 70:20, 65:25, and 60:30) with 10% malted sorghum. Proximate compositions, chemical and functional properties of the blends were analyzed. Addition of mango mesocarp flour significantly (p ≤ 0.05) increased the ash (1.31 to 1.75%), crude fibre (2.57 to 3.39%) and decreased significantly (p < 0.05) the energy content (368.21 to 354.67 kcal/100 g) of the blends. The β-carotene content also increased from 95.65 to 139.13 μg/100 g with increased mango mesocarp flour. Hygroscopicity increased significantly (p < 0.05) from 6.10 to 10.28% while viscosity of the blends decreased significantly (p < 0.05) from 1715 to 1195.46 cP. Mango mesocarp flour addition increased the ash, crude fibre and introduced β-carotene into the product.     

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.     

Acceptability of Noodles Produced from Blends of Wheat,Acha and Soybean Composite Flours

Acha (Digitaria exilis) and soybean (Glycine max) were processed into flours and used to substitute wheat flour (Titicum aestivm) as a composite flour at different proportions of 100:0:0 (Wheat); 75:25:25 (Wheat: Acha: Soybean); 75:25 (Wheat: Acha); 75:25 (Wheat: Soybean) and 50:50 (Acha: soybean). The formulated blends were used to produce noodles. The noodles were subjected to proximate analysis, functional properties and sensory evaluation using commercial instant noodles as control. The results revealed that the protein, moisture, ash and fat contents were higher in the formulated samples than in the control. Sample AS (50% Acha and 50% Soybean) had 26.47% protein and was significantly different (p < 0.05) from the control (8.97%). The protein and fat contents increased while carbohydrate decreased with increase in soybean addition to the blend. The functional properties showed that water absorption capacity increased with increase in wheat blend. There were no significant differences (p < 0.05) between the formulated samples in their swelling index and wettability. The result of the sensory evaluation based on a nine point hedonic scale showed that generally apart from the control, noodles from 100% wheat and wheat noodles supplemented with soybean up to 25% were acceptable to the panelists.     

Effect of superfine green tea powder on the thermodynamic,rheological and fresh noodle making properties of wheat flour

Superfine green tea powder (SGTP) was used to substitute 0 g, 1 g, 2 g, and 3 g of 100 g wheat flour (defined as 0SGTP, 1SGTP, 2SGTP and 3SGTP respectively) to make fresh noodles. The effects of SGTP on the viscosity, thermodynamic and rheological properties of wheat flour were evaluated, as well as the sheet colour, cooking quality, texture properties and sensory characteristics of green tea noodles. The results revealed that the stability, elastic modulus (G′) and viscous modulus (G″) of wheat dough all increased with the increase of green tea powder proportion. No significant differences were found in gelatinisation properties of the green tea-flour systems. Furthermore, adding SGTP could significantly (P < 0.05) retard the retrogradation of the gelatinised wheat flour gel. L¹ value of fresh noodles decreased as SGTP content increased while |a¹| value firstly increased and then decreased at 3 g/100 g. The 2SGTP noodle samples showed the least cooking loss. Sensory evaluation indicated that the control and the 2SGTP fresh noodles scored significantly (P < 0.05) higher in terms of colour. No significant difference was detected for the mouthfeel and overall acceptability among all samples.     

Bread from composite cassava-wheat flour: I. Effect of baking time and temperature on some physical properties of bread loaf

The use of composite cassava-wheat (CCW) flour for commercial breadmaking purposes and consumption of CCW bread are relatively new in Nigeria. This study investigated the effect of baking temperature and time on some physical properties of bread from composite flour made by mixing cassava and wheat flour at ratio of 10:90 (w/w). A central composite rotatable experimental design was used while the baking temperature and time investigated ranged from 190 to 240 °C and 20 to 40 min, respectively. Loaf volume, weight and specific volume varied significantly (p < 0.001) from 440 to 920 cm³, 162 to 183 g and 3.31 to 5.32 cm³/g, respectively. The tristimulus color parameters such as L¹ (lightness) and brownness index (BI) of the crust varied significantly (p < 0.01) from 31 to 72 and 68 to 123, respectively. Moreover, Fresh crumb moisture, density, porosity and softness as well as the dried crumb hardness were also significantly (p < 0.01) affected by both the baking temperature and time with values ranging from 34% to 39%, 0.16 to 0.20 g/cm³, 0.69 to 0.80, 13.00 to 18.05 mm and 0.90 to 2.05 kgf, respectively. Due to the complex effect of temperature and time combination, most of the measured properties could not be reliably predicted from the second order response surface regression equations except the loaf weight and crumb moisture. Further studies are required to optimize the CCW bread baking process based on some storage and consumption qualities.     

Prediction of wheat tortilla quality using multivariate modeling of kernel,flour, and dough properties

Traditional wheat quality methods for bread have poor predictive power for flatbread quality, which impedes genetic improvement of wheat for the growing market. We used a multivariate discriminant analysis to predict tortilla quality using a set of 16 variables derived from kernel properties, flour composition, and dough rheological properties of 187 experimental hard wheat samples grown across Texas. A discriminant rule (suitability for tortillas = diameter > 165 mm + day 16 flexibility score > 3.0) was used to classify samples. Multivariate normal distribution of the data was established (Shapiro–Wilk p > 0.05). Logistic regression and stepwise variable selection identified an optimum model comprising kernel weight, glutenin–gliadin ratio, insoluble polymeric proteins, and dough extensibility and stress relaxation parameters, as the most important variables. Cross-validation indicated 83% model prediction efficiency. This work provides important insight on potential targets for wheat quality genetic improvement for tortillas and specialty product market.Industrial relevanceTortillas and other flatbread manufacturers currently use wheat developed for other commodities and rely on trial and error, and use of various additives to optimize product quality. Genetic development of wheat for these markets is impeded by lack of knowledge of specific grain quality parameters to target. With the growing demand for clean label and healthy offerings by consumers, the industry is looking for natural ingredients with improved functionality. This work provides the first insight into the specific wheat composition and functional parameters that can predict tortilla quality.     

Incidence,populations and diversity of fungi from raw materials,final products and air of processing environment of multigrain whole meal bread

This study aimed to assess the incidence, to quantify and to assess the diversity of fungi in a multigrain whole meal bread processing plant. Two hundred and eight one (n = 281) samples were analyzed, including raw materials (n = 120), air samples (n = 136) and multigrain breads (n = 25). Among the raw materials, the whole corn flour showed the highest counts of fungi (4.8 log CFU/g), followed by whole-wheat flour (3.1 log CFU/g). The counts of fungi in the air of processing environment were higher in post-baking steps (oven output, cooling, slicing, packaging) than in pre-baking steps (weighing and mixer) (p < 0.05). Species of fungi isolated from spoiled bread samples stored at 5, 20, 25 and 30, and 40 °C corresponded mostly to Penicillium paneum and Penicillium polonicum isolated from 20 and 24% of samples, respectively. These species were also isolated from raw materials (P. paneum and P. polonicum) and air collected at different processing sampling points (P. polonicum). The high counts of filamentous fungi in raw materials and air samples in processing steps such as cooling, slicing, and packaging, suggest that contamination that may occur in these steps can be critical for the shelf life of breads. The results of this study highlight that the prevention of contamination of breads by fungal spores is still a challenge for bakery industries and that other strategies such as control of germination and growth of spoilage fungi through the development of more stable formulations have to be developed.     

Effect of Lactobacillus brevis-based bioingredient and bran on microbiological,physico-chemical and textural quality of yeast-leavened bread during storage

The effects of wheat bran and of a Lactobacillus brevis-based bioingredient (LbBio), obtained after growth in flour-based medium, on quality of yeast-leavened wheat bread (WWB) were investigated. Bran was used in bread formulation by substituting a part (20 g/100 g) of white wheat flour (WBB), while LbBio was used instead of the water content (WWB + LbBio and WBB + LbBio). The use of LbBio in WWB resulted in the biological acidification of the dough due to lactic, phenyllactic and OH-phenyllactic acid contents determining a high fermentation quotient value and an improved bread texture and microbiological quality. Conversely, wheat bran reduced the specific volume and crumb hardness during storage at 25 °C, and affected the antibacterial ability of LbBio during 30 °C storage. Our findings demonstrated that LbBio counteracted the negative effects of bran and allowed to obtain an enriched fibre bread with specific volume and soft crumb comparable to bread without bran.Industrial relevanceBread is a perishable food with a short microbiological and physico-chemical shelf-life. The main microbiological alteration occurring into few days after baking is the “rope spoilage” caused by spore-forming bacteria originating from raw materials. This phenomenon, often misinterpreted as a sign of unsuccessful dough leavening and not visible from outside, is more common under industrial production conditions during the hot season causing large economic losses in the warm climates of Mediterranean countries, Africa and Australia. The use of sourdough often controls this alteration even if the industrial application of this traditional process is limited by the long leavening times. In this study, an innovative procedure for the preparation of yeast-leavened bread comprising the addition of a fermentation product from Lactobacillus brevis grown in a flour-based medium has been applied. The resulting fermentation product (LbBio bioingredient) acts as a sourdough acidifying the dough and improving the textural, physico-chemical and microbiological properties of the resulting bread. The application of bioingredient LbBio could represent an innovative strategy in industrial bread production to obtain acidified yeast-leavened products, thus, preventing the ropy spoilage and reducing the negative effects of bran addition.     

Use of dried pumpkins in wheat bread production

Pumpkins belong to the family of Cucurbitaceae. They are classified to Cucurbita pepo, Cucurbita moschata, Cucurbita maxima and Cucurbita mixta, according to the texture and shape of their stems. The nutritional value of pumpkin fruits is high, varies from one species or cultivar to another. Pumpkins are reach in vitamins C, B₁, B₆, K, and in mineral substances. There are no data found about vacuum microwave dried pumpkin application in wheat bread production. The main purpose of the research was to evaluate quality parameters of microwave vacuum dried pumpkins and to verify its application in wheat bread production. Following quality parameters of pumpkins and bread made with pumpkin additive were evaluated: moisture content (oven – drying method), vitamin C content (iodometric), carotenoid content (spectrophotometric), reducing sugars (LVS 252:2000), colour changes (ColorTec- PCM), total fat content (ISO 6492:1999), degree of bread liking (ISO 4121:2003), bread baking loss and dry off. Quality parameters of non dried pumpkins were: content of reducing sugars − 2.40 g⋅100 g^-1, vitamin C – 0.26 g⋅100 g^-1, carotenoids – 0.50 mg % (in dry matter). The technological parameters for pumpkins drying in vacuum microwave drier were used: pressure (70–50 mmHg), speed of tumbler – 6 rpm, one working cycle and three stages. During the pumpkins drying process a decrease in the following parameters was observed: moisture content – 10.5 times, vitamin C content – 2.0 times; increase of yellowness (b*) value – 1.5 times. The optimal dried pumpkin additive to the wheat dough was 10% of the total flour amount. The wheat bread sample with dried pumpkins additive is richer in carotenoids and reducing sugars comparing to control wheat bread sample. The results of sensory analyses using hedonic rating demonstrated that a higher degree of liking was attributed to the bread sample with dried pumpkins additive (7.3) comparing to control wheat bread sample (6.7).     

Effect of Different Soaking Time and Boiling on the Proximate Composition and Functional Properties of Sprouted Sesame Seed Flour

The effect of soaking time on the proximate composition and functional properties of sprouted sesame seed flour were investigated. Sesame seed samples were cleaned and pretreated by soaking in clean water for 8, 10, 12, 14 and 16 h. One batch was sprouted for 36 h and another portion was sprouted and then boiled (100 °C for 20 min), dried, milled into flours and subjected to further analysis. The raw (unsprouted) sample was used as control. The proximate composition and the functional properties were determined for each of the samples and the result showed deviations in nutrient content from the raw seed flour. Moisture and protein content was increased by soaking and sprouting but reduced after boiling from a value of (4.99% and 47.64%) to (4.92% and 42.06%) respectively, for the 10 h soaked sample. Fat, crude fibre, ash and carbohydrate contents were reduced by soaking and sprouting while boiling of the sprouted seeds increased the fat and carbohydrate content. Soaking, sprouting and boiling significantly affected the functional properties of the flour (p < 0.05). Soaking and sprouting reduced the bulk density and dispersion of the samples from an initial value of (0.83% and 67.50%) for the unsprouted seed flour to a value of (0.71% and 59.00%) in 10 h soaked samples but increased slightly in most of the soaked sprouted-boiled samples. Thus, soaking of sesame seeds for 12–14 h before sprouting can be used to improve the proximate composition and functional properties of sesame seeds, hence, increase the utilization of the flour.     

The effect of moisture content and compaction on the strength and arch formation of wheat flour in a model bin

An experimental study was carried out to determine the effect of compaction on arching of wheat flour in storage. A model bin 475 mm in height and 600 × 375 mm in cross-section was used to conduct tests and wheat flour at moisture contents (MC) of 8.6% and 14.2% was tested. Direct shear tests were performed to determine the angle of internal friction and cohesion of wheat flour subjected to various compaction pressures. It was observed that the internal friction angles were about the same for the wheat flour at two moisture contents (37.6° vs. 37.5°), but cohesion for 14.2% MC was 72% higher than that for 8.6% MC. The flowability of wheat flour decreased with increasing compaction pressure sharply at the initial stage of compaction. Compaction led to a 64% increase in required hopper opening for arching-free flow for flour at 8.6% MC, and 49% at 14.2% MC. However, compaction pressure had little effect on arch formation after it reached above 5 kPa.     

Effect of Soy Flour and Maize Flour Addition on Phase Separation in Moi-Moi from Soaked Cowpea (Vigna unguiculata) and Cowpea Flour from Different Cowpea Varieties

Two improved varieties of cowpea (IT89KO and IT90K-76) and one local variety (lsiocha) were used to investigate the effects of added soyflour and maize flour on the phase separation in moi-moi made from soaked cowpea and cowpea flour. Different levels (5%, 10%, 15%, 20% and 25%) of maize flour, soyflour and a 1:1 blend of soyflour and maize flour (soy/maize flour) were separately added. The moi-moi from the different combinations was evaluated for phase separation and per cent height of the upper layer calculated. Soaking of cowpea reduced the size of the upper layer in moi-moi compared with the use of cowpea flour. The addition of maize flour or the soy/maize flour reduced the upper layer compared with when either flour was added alone. The upper layer of moi-moi made from cowpea flour with added soy flour (21.20%) was significantly higher (p < 0.05) than moi-moi from soaked cowpea with added soy flour (15.2%). Moi-moi with added maize flour made from cowpea flour produced a significantly (p < 0.05) higher mean per cent upper layer (19.72%) compared with that from soaked cowpea (8.95%). Addition of soyflour produced the greatest upper layer for all varieties used. There were no significant (p > 0.05) differences in the per cent upper layers for moi-moi from all cowpea varieties when maize flour was added. Increasing the proportion of added flours increased the size of the upper layer. Complete prevention of the occurrence of phase separation in moi-moi by addition of soy flour and maize flour alone is not feasible.