A.H. El Tinay

Solubility and functional properties of sesame seed proteins as influenced by pH and/or salt concentration

Abstract The protein content, solubility and functional properties of a total protein isolate prepared from sesame seeds (Kenana 1 cultivar) as a function of pH and/or NaCl concentration were investigated. The protein content of the seed was found to be 47.70%. The minimum protein solubility was at pH 5 and the maximum was at pH 3. The emulsifying capacity, activity and emulsion stability as well as foaming capacity and foam stability were greatly affected by pH levels and salt concentrations. Lower values were observed at acidic pH and high salt concentration. The protein isolate was highly viscous and dispersable at pH 9 with water holding capacity of 2.10 ml H 2 O/g protein, oil holding capacity of 1.50 ml oil/g protein and bulk density of 0.71 gm/ml.

Proximate composition, starch, phytate and mineral contents of 10 pearl millet genotypes

Abstract Ten pearl millet genotypes: IS 91777, IS 91666, IS 91333, IS 89111, IS 880004, IS 843, IS 833, Kabti, YD-X3 and Tihama, were used in this study. Investigations showed that pearl millet contained 88–91% dry matter, 1.6–2.4% ash, 2.6–4.0% crude fibre, 2.7–7.1% oil, 8.5–15.1% crude protein, 58–70% starch and 354–796mgg−1 phytic acid. Mineral contents were 10–80, 180–270 and 450–990mgg−1 Ca, Mg and P, respectively, and 70–110, 4–13, 53–70, 18–23, 10–18 and 70–180 μgg−1 K, Na, Zn, Mn, Cu and Fe, respectively. The percentage of phytate to total phosphorus was found to range from 70–89% with an average of 77%. A linear relationship between phytate and total P existed with a correlation coefficient of 0.9805.

Changes in fatty acids composition during seed growth and physicochemical characteristics of oil extracted from four safflower cultivars.

Fatty acid contents at different stages ofmaturity and physicochemical characteristics of oilextracted from mature seeds of four safflowercultivars (S208, S400, S541, and S303) were studied. Results indicated that for all cultivars bothsaturated and unsaturated fatty acid contentsfluctuated with seed growth and development. Palmiticacid content decreased up to day 20 after which itstarted to increase for the S400, S541, and S303cultivars, while for S208 it progressively decreased.Stearic acid fluctuated with seed growth anddevelopment. Oleic acid showed slight changes withseed growth and development, while linoleic aciddecreased with seed growth and development for theS400, S541, and S303 cultivars while for S208 afterday 30, it started to increase significantly. For allcultivars, glyceride contents varied among thecultivars with maximum values of 97.70, 2.80 and0.20 for tri-, di- and monoglycerides, respectively. Physicochemical investigation of mature seed oilsshowed that the color, density, refractive index, free fatty acids, peroxide value, saponificationvalue and unsaponifiable matter were similar for allcultivars while viscosity, iodine value, and acetoneinsoluble matter varied among the cultivars.

Effect of malt pretreatment on phytic acid and in vitro protein digestibility of sorghum flour

Sorghum seeds of cultivar Wad Ahemed (phytate: 2.7 mg/g, tannin: 0.96% and 2 h pepsin digestion: 18%) were germinated for three days to obtain 1-, 2- and 3- days old sorghum malts. Sorghum malt was added in concentrations of 1, 2.5, 5, 7.5 or 10% to sorghum flour. The mixtures were incubated with shaking for 0, 30, 60, 90 or 120 min. Phytic acid and in vitro protein digestibility were assayed for all treatments. The results revealed that phytate content was significantly reduced. The 10% 3-day-old malt after 120 min incubation, reduced the phytate content by 83%. The in vitro protein digestibility (IVPD) was significantly improved as a result of malt pretreatment. The rate of reduction of phytate content and the rate of increment in IVPD increased with time of incubation, age and concentration of the malt.

Growth and Apparent Absorption of Minerals in Broiler Chicks Fed Diets with Low or High Tannin Contents

Sorghum grains with low (0.28 per cent catechin equivalent (%CE) or high (1.36 %CE)) tannin contents were used to study the effect of tannin on growth and on the apparent absorption of Ca, P, Mg, Na, K, Fe and Co by chickens. High-tannin sorghum caused a highly significant (p≤0.01) reduction in the weight gain and feed intake of broiler chicks compared to low-tannin sorghum and increased the feed conversion ratio (p≤0.01). The amount of tannin did not affect mortality. The apparent absorption of Ca, P, Mg, Na, K, Fe and Co was reduced (p≤0.01) by feeding sorghum grains with a high tannin content.

Effect of traditional processes on phytate and mineral content of pearl millet

Abstract Six pearl millet genotypes were used in this study: IS 91333, IS 91666, and IS 89111 for dough fermentation and IS 880004, IS 91777 and YD-X3 genotypes for Damirga flour. Investigation showed that traditional fermentation for 14 h at 37 °C caused a decline in pH with time; a sharp drop was observed at the beginning, which gradually levelled off. Fermentation resulted in significant reduction of starch and phytic acid: 9.5–9.8% and 43–44%, respectively. Protein content was not affected. The Damirga process significantly elevated starch content (by 8–19%) but significantly reduced the protein and phytic acid contents (by 10.9–12.1 and 86–93%, respectively). Damirga flour was found to retain 25–84% of the major minerals (Ca, Mg, P, K and Na) and 52–65% of the minor minerals (Zn, Mn and Fe); losses occurred for all minerals except Cu.

Effect of nitrogen fixation, nitrogen fertilization and viral infection on yield, tannin and protein contents and in vitro protein digestibility of faba bean

A field investigation of two faba bean cultivars (cv.), Agabat and Silaim, showed that bean yellow mosaic virus (BYMV) infection reduced (p≤0.001) yield (Kg/ha), protein content and in vitro protein digestibility (IVPD) but increased (p≤0.05) tannin content (mg/100 ml). Nitrogen fertilization with viral infection significantly reduced yield and IVPD for cv. Silaim and increased (p≤0.05) protein and tannin contents. Nitrogen fertilization alone was found to increase (p≤0.05) yield, protein and tannin contents but slightly reduced IVPD.Rhizobium inoculation with viral infection significantly decreased yield per unit area, protein content and IVPD, but increased (p≤0.05) tannin content.Rhizobium inoculation alone significantly increased (p≤0.001) yield and tannin content and slightly increased protein content but decreased IVPD. The results indicated that nitrogen fertilization or nitrogen fixation increased yield, protein and tannin contents and decreased IVPD. Viral infection had an adverse effect on yield, protein content and IVPD but had no effect on tannin content.

Biochemical and physical changes in fruits of four guava cultivars during growth and development

Abstract Biochemical and physical changes in fruits of four guava cultivars during growth and development were studied. Investigation showed that protein content decreased markedly with fruit growth and development for all cultivars. The maximum level of reduction varied from 0.25 to 0.27%. Moisture content was significantly increased with fruit growth and development in all cultivars. The maximum level varied from 6.2 to 76.0%. Alcohol-insoluble solids (AIS) declined gradually during the initial growing period followed by rapid decline during later stages of development for all cultivars, which differed in their final value (8.67–13.33%). Water-soluble pectin for all cultivars increased gradually with fruit development. The maximum level varied from 0.34 to 0.64%. For all cultivars texture declined gradually during fruit development. The skin colour of the fruit changed gradually from dark green to yellow for all cultivars. Fruits picked before day 106 after fruit set had a reading of more than 30 psi (1 psi ≈ 7.9kPa) which was outside the range of the pressure tester, and thereafter pressure declined rapidly for all cultivars. Fruit volume increased rapidly with fruit development for all cultivars. Softness and yellowness of fruit were associated with lower protein and AIS contents, higher moisture and appreciable amounts of water-soluble pectin.

Effect of cooking on anti-nutritional factors and in vitro protein digestibility (IVPD) of faba bean grown with different nutritional regimes.

A field experiment was carried out to study the effect of cooking on IVPD and anti-nutritional factors of mycorrhizal-inoculated, phosphorus- and sulphur- fertilized faba bean plants. The results indicated that cooking significantly increased protein digestibility for the control and all treated samples. The increased IVPD was a consequence of significant reduction in antinutritional factors (tannins and phytic acid).

Effect of reducing agents on the in vitro protein and starch digestibilities of cooked sorghum

Abstract A low-tannin sorghum cultivar M-35-1 was used in this study. Investigation showed that the in vitro protein digestibility (IVPD) decreased considerably when sorghum flour was cooked in water, while it increased when cysteine, sodium metabisulphite, or ascorbic acid were added to the cooking medium. The increase in the IVPD was significantly higher with increasing concentrations of cysteine up to 0.25 M and it continued to increase to 0.5 M for sodium metabisulphite; with ascorbic acid it increased up to 0.1 M then decreased. The in vitro starch digestibility (IVSD) of the treated gruel initially increased in the presence of either cysteine, sodium metabisulphite or ascorbic acid. The increase was parallel to that shown by IVPD; however, at high levels of cysteine or sodium metabisulphite the IVSD was low. Removal of cysteine from the gruel by alcohol gave higher IVSD. Altered viscosity patterns for all the treatments led to increase in the gelatinization temperature, peak viscosity and breakdown. However, the setback decreased in all treatments. Cysteine and ascorbic acid gave a negative setback but when the pH was adjusted to 4.5 or 7.0 a normal setback was obtained. ©