Physicochemical and thermal properties of taro (Colocasia esculenta sp) powders as affected by state of maturity and drying method.

The study was aimed at determining the effect of harvesting time and drying method on the thermal and physicochemical properties of taro powder, Sosso ecotype. A 5 × 2 factorial experiment with 5 harvesting times (6, 7, 8, 9 and 10 months after planting) and 2 drying methods (sun and electric oven drying) was used for this purpose. The variance component analysis revealed harvesting time as the most important factor affecting all the variables measured. In particular the proteins and available sugar contents of the powders increased significantly with increase in harvesting time. The same was true of the gelling property and water absorption capacity of the powders. It was equally observed that the temperatures (start, peak and end) and enthalpy of gelatinization of the powders increased with harvesting time. It is concluded that harvesting sosso-taro at full maturity (10 months after planting) and sun-drying produces food powders with excellent gelling properties among others.

Glycosyl part identified within Balanites aegyptiaca fruit protease.

The many milk-clotting proteases from plant are glycosylated; attachment of monosaccharides to enzyme is an advantage for its activity and stability. In this study, gas chromatography coupled to mass spectrometry-electrospray ionization was used to identify glycans bond to proteases purified from Balanites aegyptiaca fruits pulp through cation exchange chromatography. Carbohydrates were identified according to the retention time and the ion at m/z after derivation by heptafluorobutyric acid. The chromatograms obtained from monosaccharides analysis revealed the presence of galactose, mannose, arabinose, xylose, rhamnose and glucuronic acid. The mass spectrometry-electrospray ionization spectra corroborated these findings.

Salts soaking treatment for improving the textural and functional properties of trifoliate yam (Dioscorea dumetorum) hardened tubers.

Processing of Dioscorea dumetorum hardened tubers into flour could be a means of adding a longer-term value to this tropical plant with a high nutritional potential, but which presents a postharvest hardening problem characterized by a hard-to-cook defect. In an attempt to investigate the changes leading to salts soaking treatment of hardened tubers, the central composite rotatable design for K= 2 was used to study the combined effect of NaCl concentration (0% to 6%) and pH (4 to 10) on tubers cooked hardness, and 6 kanwa alkaline salt concentrations (1:3 (w/v); 0%, 0.2%, 0.5%, 0.8%, 1%, and 1.5%; pH 11.3 +/- 0.2) were used to study the effect of kanwa treatment on tuber cooked hardness and functional properties of resulting flours. The results showed that salts soaking treatment significantly decreased (P

In vitro protein digestibility and physicochemical properties of dry red bean (Phaseolus vulgaris) flour: effect of processing and incorporation of soybean and cowpea flour.

A study was carried out to determine the effect of germination and drying temperature on the in vitro protein digestibility and physicochemical properties of dry red bean flours. A 2 x 3 factorial experiment with two treatments (germination and nongermination) and three drying temperatures was used for this purpose. The effect of particle size on water absorption capacity of bean flour was investigated. In addition, the effect of incorporating soybean and cowpea into the red bean flour on functional properties was equally investigated. Results reveal that protein digestibility increased with germination and also with drying temperature. Drying at 60 degrees C produced flours of optimum functional characteristics, although the hydrophilic/lipophilic index was high and the solubility index reduced. Germination and particle size as well as drying temperature all affected the water uptake properties of bean flours. Incorporation of soybean and cowpea flour into germinated bean flour at levels of 10 and 30%, respectively, produced a composite with higher functional properties.

Nutritional and sensory evaluation of akara made from blends of cowpea and hard-to-cook mottled brown dry beans.

The effect of replacing cowpea with hard-to-cook beans on the nutritional and sensory properties of akara were evaluated. Cowpea (Vigna unguiculata), traditionally used for making akara, was substituted 0%, 25%, 50%, 75%, and 100% with hard-to-cook (HTC) mottled brown beans (Phaseolus vulgaris). Cowpea (CP) soaked for 60 min HTC beans soaked for 18 h were separately decorticated, ground to a paste, and mixed in the following CP:MBB ratios: 0:100, 25:75, 50:50, 75:25, and 100:0. The paste mixtures were each whipped and fried into akara. The samples were analyzed for bulk density, nutritional composition, carbohydrate and protein digestibility, alpha-amylase inhibitor and trypsin inhibitor activity, and sensory attributes. The bulk density of paste as well as of akara increased with the increasing content of HTC bean. Akara made from composite paste had a relatively better amino acid profile. Frying beyond 5 min destroyed the alpha-amylase inhibitors as well as the trypsin inhibitor activity. No significant difference was observed in the overall acceptability of akara made from cowpea substituted up to 50% with HTC beans. Hence, this approach permits the utilization of hard-to-cook beans.

Use of two varieties of hard-to-cook beans (Phaseolus vulgaris) and cowpeas (Vigna unguiculata) in the processing of koki (a steamed legume product).

Koki is a nutritious cowpea-based food product usually processed by steam cooking whipped cowpea (Vigna unguiculata) paste mixed with spices and palm oil. A study was carried out to investigate the effect of the partial replacement of cowpeas (CP) with hard-to-cook (HTC) beans on the chemical, nutritional and sensory characteristics of koki. Towards this objective, two varieties of beans--Phaseolus vulgaris (red kidney beans--RKB and mottled brown beans--MBB), each with the HTC defect, were separately incorporated into cowpea paste in the following Bean:CP ratios 0:100, 20:80, 30:70, 40:60, 50:50, 60:40 and processed into koki. Incorporation of dry HTC beans into cowpeas in the making of koki affected the bulking properties of the uncooked paste, the nutrient composition, essential amino acid content, antinutritional factors, digestibility as well as the sensory attributes of cooked koki. Sensory tests showed that a highly acceptable, nutritious and digestible koki can be processed from cowpeas partially replaced with dry HTC bean paste up to levels of about 40-50% depending on the variety of dry bean used.

Soluble and insoluble fiber contents of some Cameroonian foodstuffs.

As a result of the lack of reliable data on the fiber content of African foodstuffs, a study to determine the dietary fiber contents (soluble, insoluble and total) on a dry weight basis of a selected variety of major Cameroonian foods was conducted. The influence of processing and preparation methods on the fiber content was also assessed. Vegetables were found to be the richest source of total dietary fiber (57%), followed by legumes and seeds (30%) and fruits (16.5%). Okro (Hibiscus esculenta), plantain (Musa paradisiaca) and beans (Phaseolus spp) showed varietal differences in their soluble and insoluble fiber content, while methods of processing and preparation significantly influenced the fiber content of cassava (Manihot esculenta), corn (Zea mays) and beans.

Nitrogen balance study in young Nigerian adult males using four levels of protein intake.

1. The present study was carried out to estimate precisely, via the nitrogen balance technique, the protein requirement of Nigerians (earlier estimated via the obligatory N method) using graded levels of protein intake. 2. Fifteen medical students of the University of Ibadan who volunteered to participate in the study were given graded levels of protein (0.3, 0.45, 0.6 and 0.75 g/kg body-weight per d) derived from foods similar to those usually consumed by the subjects. 3. Each subject was given each of the dietary protein levels for a period of 10 d. Subjects were divided into two groups and the feeding pattern followed a criss-cross design with one group starting with the highest level of protein intake (0.3 g). Mean energy intake during each of the eleven experimental periods was maintained at 0.2 MJ/kg per d. After an initial 5 d adaptation period in each experimental period, 24 h urine and faecal samples were collected in marked containers for five consecutive days for N determination. 4. Mean N balance during consumption of the four protein levels (0.30, 0.45, 0.6 and 0.75 g/kg) were -11.02 (SD 8.07), -9.90 (SD 6.64), +9.70 (SD 4.15) and +5.13 (SD 4.62) respectively. Using regression analysis, the mean daily N requirement was estimated at 110.25 mg N/kg body-weight (0.69 g protein/kg body-weight). Estimates of allowances for individual variations to cover 97.5% of the population adjusted this value to 0.75 g protein/kg body-weight. Net protein utilization for the diet at maintenance level was estimated at 57.5.

Long-term evaluation of the adequacy of habitual diets to provide protein needs of adult Nigerian men.

1. A continuous 40 d metabolic nitrogen balance study was conducted on twelve young men aged 25 (SD 2.6) years to evaluate the adequacy of a previously determined safe level of protein intake. 2. Subjects were fed on diets which they were habitually accustomed to and which provided a protein level of 0.75 g protein (N x 6.25)/kg body-weight per d as the safe level and an energy intake level of 0.2 MJ/kg body-weight per d. N balances, including an estimate for integumental losses as well as certain biochemical variables, were determined for the last 5 d of two consecutive 20 d diet periods. 3. Only two of the twelve subjects were observed to be in negative N balance the final 5 d of the 40 d period. N balance was generally positive at 8.24 (SD 8.61) mg N/kg body-weight, thus confirming the adequacy of 0.75 g protein/kg body-weight per d as a safe level of protein intake in the majority of the subjects.

Human protein requirements: obligatory urinary and faecal nitrogen losses and the factorial estimation of protein needs of Nigerian male adults.

1. The present study was designed to use the factorial approach to estimate protein requirements of Nigerian male adults by measuring obligatory nitrogen losses via urine, faeces and sweat when N intake was very low and energy intake adequate. 2. Eight adult men from Osegere village near Ibadan and seven medical students from the University of Ibadan, who volunteered to participate as subjects in the study, were given a low-protein diet (based on staple foods habitually consumed by subjects) for 10 d. Mean daily total protein intake was 4.68 g while that of energy was 0.2 MJ/kg body-weight. After an initial 5 d adaptation period, 24 h urine and faces were collected in marked containers for five consecutive days for N determination. N losses from the skin were also determined in the village adults. 3. Mean daily urinary, faecal and sweat N losses (mg N/kg body-weight) were 45.88 (SD4.84), 21.79 (SD4.19), and 7.46 (SD1.71) from the village adults. The corresponding urinary and faecal N losses from the university students were 43.45 (SD2.28) and 18.32 (SD4.66) (sweat N loss not measured). Thus the total daily obligatory N losses (per kg body-weight) from the village adults and university students were 75.13 and 69.23 mg N respectively (assuming a sweat N loss of 7.46 mg for the university students). After adjusting for requirement and making a 30% allowance for individual variability, the safe level of protein intake was calculated to be 0.78 and 0.73 g protein/kg body-weight for the village men and university students respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Zinc, copper and iron concentrations in the plasma and diets of lactating Nigerian women.

Zinc, copper, iron, protein and energy intakes of 232 lactating women (consuming self-selected diets during the first 3 months post-partum) were computed from food intake values obtained using a 3 d dietary-recall method. Non-pregnant, non-lactating women (100) served as controls. Blood samples of subjects were also analysed for packed cell volume and haemoglobin concentrations as well as for plasma Zn, Cu and Fe levels by atomic absorption spectrophotometry. Except for Fe, intakes of all nutrients measured were significantly lower than recommended dietary allowances for lactation. Daily mean (and SD) Zn, Cu, Fe (mg), protein (g) and energy (MJ) intakes for lactating women were 8.2 (1.6), 1.6 (0.5), 29.0 (5.8), 52.4 (9.2) and 10.21 respectively. There was a significant intercorrelation between the different nutrients in the diet. Mean (and SD) plasma Zn, Cu and Fe concentrations (micrograms/l) during the first 3 months of lactation were 666.0 (76.0), 1290.0 (150.0) and 730.0 (185) respectively. These values were significantly (P less than 0.05) lower in the case of Zn and Fe and higher in the case of Cu than those of non-pregnant, non-lactating women. Maternal plasma levels of the trace elements also varied significantly with nutritional status as indexed by haemoglobin status. Correlation analysis between dietary and plasma trace element concentrations was significant for Zn (r 0.26, P less than 0.0001) and Fe (r 0.17, P less than 0.05). Dietary protein intake was significantly correlated with plasma Zn (r 0.18, P less than 0.005) and Fe (r 0.12, P less than 0.05). While maternal weight, arm circumference and skinfold thickness measurements tended to decrease with increase in the period of lactation, growth performance of entirely breast-fed babies was satisfactory as at the 12th week post-partum.

Relationship between dietary and plasma copper levels of pregnant Nigerian women.

Dietary copper intake as well as plasma copper levels were assessed in a group of pregnant Nigerian women during the third trimester of pregnancy. Intake of zinc, protein and energy was also measured. Dietary intake was assessed by cumulative 24-hour recalls while plasma copper was assessed by atomic absorption spectrophotometry. Dietary copper levels were relatively lower than those documented in the literature for other physiological groups. The intake of other nutrients was below recommended dietary allowances. When corrected for the effect of gestation and maternal age, one-way analysis of variance showed that plasma copper varied with the level of dietary copper intake. Correlation analysis seems to suggest that the influence of dietary copper on plasma levels during pregnancy is partially dependent on the relative amounts of copper and zinc as represented by the copper:zinc ratio in the diets consumed.

Mineral content of colostrum and mature milk of lactating Nigerian women as influenced by stage of lactation.

380 milk samples (96 colostrum and 284 mature milk samples) collected from 240 lactating Nigerian women within the first 9 months of lactation were analyzed for zinc, copper, iron, calcium, and magnesium concentrations by atomic absorption spectrophotometry. Mean levels of zinc, copper, iron, calcium, and magnesium in colostrum were 5.83, 0.52, 0.55, 400, and 33 mcg/ml, respectively; the levels for the same minerals in mature milk collected in the 8th and 12th week of lactation were 3.08, 0.29, 0.38, 300, and 31 mcg/ml, respectively. While milk levels of all minerals decreased with increase in lactation age, zinc levels showed the fastest rate of decrease. Milk zinc levels at the 9th month were only 13% of that in colostrum. Similar percentages for copper, iron, calcium, and magnesium were 49, 60, 34, and 74%, respectively. Estimates of intake by solely breastfed infants during the first 6 months showed gross inadequacies when compared with Recommended Daily Allowances. Results suggest the need for early supplementation, especially as zinc deficiencies as well as a high incicdence of iron deficiency anemia has been reported in Nigerian infants.