Influence of pH and sodium chloride on selected functional and physical properties of African breadfruit (Treculia africana Decne) kernel flour.

African breadfruit seeds were cleaned, parboiled (98 degrees C) for 15 min, drained and dehulled. The kernels were sun-dried, then milled and sieved into flour. Nitrogen solubility (NS), water absorption capacity (WAC), emulsion activity (EA), viscosity, foaming and emulsifying properties of the flour were determined as functions of pH and NaCl concentration. The NS was pH dependent with a minimum at pH 4 and maximum at pH 10. The flour also exhibited minimum and maximum foam capacity at pH 4 and 10, respectively. The minimum emulsion activity was at pH 4, a value which increased from 7-16% at pH 12. The addition of NaCl at concentrations of 0.2 to 0.4 M improved WAC, NS, foaming and emulsion properties of the flour. Sodium chloride enhanced NS of the flour at pH 4-6 and EA at pH 2-8. The EA at pH 2, 10 and 12 correlated negatively (r = -0.30) with NaCl concentration levels; however, the correlation was not significant (p > 0.05). The flour dispersions had lower viscosities at acid pH and in the presence of NaCl than at neutral and alkaline pH values. Results indicated the flour could be used in food product supplementation.

Effects of debittering methods on the proximate composition, organoleptic and functional properties of sesame (Sesamum indicum L.) seed flour.

Sesame seeds were boiled and allowed to sprout under ambient condition (30 +/- 2 degrees C) with an objective to reduce or eliminate the bitter taste associated with them. The untreated seeds were used as a control. The proximate composition, functional and organoleptic properties of defatted sesame flour were assessed at room temperature. There was slight increase (about 10%) in protein content of sprouted seeds. The foaming capacity of flours from untreated, sprouted and boiled seeds were 34.6, 38.5 and 11.5%, respectively. The flour from the boiled seeds had the highest foam stability. Flours from untreated or sprouted seeds, gelation started at the least concentration of 6% whereas that from boiled seed was 11%. The emulsion capacity of flours from the untreated or sprouted seeds was the same (27.6 g oil/g sample) while that from boiled seeds was 12.9 g oil/g sample. Emulsion stability with prolonged storage appeared to be more with flours from the sprouted or boiled seeds than that from the untreated ones. The water absorption properties of flours from the untreated, sprouted and boiled seeds were 8.0, 5.9 and 6.5 g H2O/g sample, respectively whereas the oil absorption capacity same (5.9 g oil/g sample). The bitter taste in flours from the untreated or sprouted was high. The bitter taste was not detected in flour from boiled seeds and the functional properties of the flour were not deleteriously affected except foaming and emulsion capacity. Therefore, this boiling method of debittering sesame seed could be practised. The quality of sesame flour obtained with this boiling method could still serve its role in traditional dishes and in the formulation of some other conventional food products.

The fate of beta-carotene in processed leaves of fluted pumpkin (Telfairia occidentalis hook. f.): a popular vegetable in Nigerian diet.

The effects of blanching, sun-oven-drying and storage conditions on beta-carotene content of the fresh leaves of fluted pumpkin were investigated. The beta-carotene (mg/100 g) of fresh leaves (unblanched) was 98.9 whereas on blanching the value was reduced to 86.3 for steam blanch and 83.8 for water blanch. After dehydration the losses in the beta-carotene were in the ranges of 37.6 to 48.8%, 40.5 to 51.3% and 68.8-72.0% for the steam-, water-blanched and unblanched leaves, respectively. The lower limit loss values were for the oven-dried leaves whereas the upper limit values were obtained from sundried ones. The ambient (30 +/- 2 degrees C) and refrigeration (7 +/- 1 degree C) storage conditions showed some slight changes in beta-carotene contents of the leaves. The losses were in the ranges of 2.0 to 25.7% (refrigeration) and 9.2 to 36.3% (ambient) conditions. Blancing and storage conditions affected the organoleptic characteristics of the leaves.

Food potentials of some unconventional oilseeds grown in Nigeria--a brief review.

A brief review of literature on kernels of Citrullus and Cucumeropsis ('egusi' melon) species, Telfairia occidentalis (fluted pumpkin), Lagenaria (gourd) species of all of Cucurbitaceae family and other oilseeds such as Pentaclethra macrophylla (African oil bean), Parkia spp. (African locust bean) both of Mimosaceae family and Butyrospermum paradoxum (shea butter) of Sapotaceae family which are grown and widely used as food in Nigeria is presented. The kernels of species of Cucurbitaceae form the bulk of unconventional oilseeds used for food in Nigeria. The nutritional value of some of the kernels and the physicochemical properties and storage stability of the oils obtained from them are discussed. The various consumable forms in which they exist are also described. The problems and prospects of these neglected oilseeds in Nigeria are highlighted.

Chemical composition of kernels from some species of Cucurbitaceae grown in Nigeria.

The seeds of lesser-known species - Cucumeropsis mannii, Lagenaria sicceraria varieties 1 and 2 and Telfairia occidentalis, of Cucurbitaceae family were studied. The protein content of C. mannii was 36.1% and the varieties 1 and 2 of L. sicceraria had 32.1% and 33.3% respectively. Telfairia occidentalis had protein content of 33.2%. The fat contents of C. mannii, L. Sicceraria var. 1 and 2 and T. occidentalis were 44.4%, 44.6%, 46.9% and 42.3% respectively. The crude fibre content for each of the two varieties of L. sicceraria was 3.6% and T. occidentalis had 5.5%. Cucumeropsis mannii had the lowest (2.4%) fibre content. The carbohydrate contents for L. Sicceraria var. 2, C. mannii, and T. occidentalis were 12.6%, 13.2% and 14.4% respectively. Lagenaria sicceraria var. 1 had the highest value of carbohydrate (15.8%). The species were relatively rich in potassium and magnesium with range of values of 0.56% to 0.68% and 434 ppm to 444 ppm respectively. Cucumeropsis mannii and Lagenaria sicceraria var. 2 had relatively high contents of calcium (117 ppm) and iron (109 ppm) respectively. The kernels of these species exhibited lipase activity. Telfairia occidentalis showed the highest degree of lipase activity.

Effect of blanching and drying methods on the nutritional and sensory quality of leafy vegetables.

The nutrient retention and sensory quality factors of vegetables blanched by two methods and solar-dried or dried in the cabinet dryer were evaluated. The type and conditions of the blanching treatment prior to drying affect the retention of ascorbic acid, carotene, and ash in the dried vegetables. The sun-dried vegetables had inferior colour, texture and acceptibility compared to the vegetables dried in the cabinet dryer. There were significant differences in the rehydration and drying ratio of the dried vegetables. The implications of the blanching and drying processes for an effective preservation technique are discussed.