Physical properties and water absorption kinetics of three varieties of Mucuna beans.

The physical properties and water absorption kinetics of three varieties of Mucuna beans (Mucuna pruriens, Mucuna rajada and Mucuna veracruz) were determined in this study. Physical properties including length, width, thickness, geometric mean diameter, sphericity, porosity, bulk density, area, volume and one thousand seed mass were calculated while hydration kinetics was studied by soaking Mucuna beans in water at 30 °C, 40 °C and 50 °C and measuring water uptake at 9 h interval. Peleg's equation was used to model the hydration characteristics and Arrhenius equation was used to describe the effect of temperature on Peleg's rate constant k1 and to obtain the activation energies for soaking. Significant variations were observed in almost all the physical properties of the different varieties, however, there were no significant differences (p < 0.05) in their thicknesses and bulk densities. The effectiveness of fit of Peleg's model (R2) increased with increase in soaking temperature. Peleg's rate constant k1 decreased with increase in soaking temperature while k2 increased with temperature increase. Activation energies of Mucuna pruriens, Mucuna rajada and Mucuna veracruz were 1613.24 kJ/mol, 747.95 kJ/mol and 2743.64 kJ/mol, respectively. This study provides useful information about the properties of three varieties of Mucuna beans that could be of importance to processors and engineers for process design and optimization.

Evaluation of some quality parameters of cassava starch and soy protein isolate matrices during deep fat frying in soybean oil.

Snack industry is recently focused on the production of snacks with minimal oil content and enhanced quality attributes which prompted the need to study the changes in snack matrices produced from cassava starch processed from three varieties of cassava roots (TMS-950289, TME-419, and TMS-30572) and soy protein isolate blends fried in soybean oil. Effect of frying temperature (170-180°C), frying time (2-4 min), soy protein isolate inclusion level (5%-15%) on proximate composition, color changes, expansion, texture, and sensory attributes of the snacks was investigated. Optimization of process variables was carried out based on a factorial design (2 level by 3 factor) in the Design Expert version 6.0.8, and models were generated showing the relationship between the independent variables and the responses. The desired goal for each constraint (processing conditions) was kept within 170-180°C for 2-4 min, while all responses, except chewiness, expansion, yellowness, and protein, were set at minimum. Evaluation of sensory attributes of the optimized sample was carried out to determine its level of desirability. The optimized frying conditions for matrices produced from starches of TMS-950289 are 170°C/4 min/5% SPI with desirability value of 0.507; from TME-419 are 180°C/2 min/5% SPI with desirability value of 0.475 while for those from TMS-30572 are 170°C/4 min/15% SPI with desirability value of 0.459. At higher SPI level, the protein content was high at 170°C. At 4 min frying time for all the varieties, the moisture content reduces. The most desired optimized fried snack produced from starch of TMS-30572 (containing 15% SPI) had higher crispness and lower oil content than other optimized fried snacks.

Nutrient composition, functional, and pasting properties of unripe cooking banana, pigeon pea, and sweetpotato flour blends.

This study investigated some quality attributes of unripe cooking banana (UBF), pigeon pea (PPF), and sweetpotato (SPF) flour blends. Simplex centroid mixture design was used to obtain 17 blends from the flours. The nutrient composition, color, and functional properties of the blends were evaluated using standard methods. Data were subjected to analysis of variance and treatment means were compared using Duncan's multiple range test at 5% probability level. There were significant (p < .05) differences in the nutrient composition, and functional and pasting properties of the blends. The crude protein, crude fiber, ash, foaming capacity, emulsion capacity, and least gelation capacity of the blends increased as the PPF level increased. The blends had Na/K ratio of <1.0. The dispersibility, bulk density, water, and oil absorption capacities of the blends increased as SPF and UBF increased. The peak, setback, and final viscosities increased as UBF and SPF inclusion increased,whereas pasting temperature and time increased as the PPF level increased. The L*, a*, and b* values of the flour blends which were significantly (p < .05) different ranged from 79.58 to 102.71, -0.15 to 2.79, and 13.82 to 23.69, respectively. Cooking banana-pigeon pea-sweetpotato flour blends are desirable for alleviating malnutrition in Nigeria and developing new food formulations.

Effects of processing and storage conditions of cocoyam strips on the quality of fries.

The effects of blanching time and temperature on the sensory and textural properties of frozen cocoyam strips were studied for cocoyam varieties. The most preferred variety after sensory evaluation was blanched at 90°C for 5 min, reproduced, and frozen at a temperature of -18°C for storage studies over a period of 12 weeks with Irish potato as control. Sensory evaluation and instrumental texture analysis of frozen fried samples were conducted at 3 weeks intervals for 12 weeks. Sensory evaluation during storage showed no significant difference (P < 0.05) in taste, aroma, and mouth feel attributes between control and cocoyam fries. The sensory score for taste, sogginess, and mouth feel increased while those for aroma and color decreased in comparison with the control fries over storage. The texture increased during storage and for control fries. There was a significant negative correlation between sogginess, hardness, and dry matter, respectively.

Effect of species, pretreatments, and drying methods on the functional and pasting properties of high-quality yam flour.

The study investigated the functional properties of HQYF (high-quality yam flour) from tubers of four dioscorea species. The tubers were processed into HQYF using two pretreatments (potassium metabisulphite: 0.28%, 15 min; blanching: 70°C, 15 min) and drying methods (cabinet: 60°C, 48 h; sun drying: 3 days). Significant differences (P < 0.05) were observed in pasting characteristics of flours among the four species. The drying method significantly affected only the peak viscosity. The interactive effect of species, pretreatment, and drying methods on the functional properties was significant (P < 0.05) except for emulsification capacity, angle of repose, and least gelation concentration. The significant variation observed in most of the functional properties of the HQYF could contribute significantly to breeding programs of the yam species for diverse food applications. The pastes of flour from Dioscorea dumetorum pretreated with potassium metabisulphite and dried under a cabinet dryer were stable compared to other samples, hence will have better applications in products requiring lower retrogradation during freeze/thaw cycles.

Optimization of some processing parameters and quality attributes of fried snacks from blends of wheat flour and brewers' spent cassava flour.

The effect of some processing parameters (frying temperature [140-160°C], frying time [2-4 min], level of brewers' spent cassava flour (BSCF) [20-40%], and thickness [2-4 mm]) on some quality attributes of wheat-BSCF fried snack was investigated. Response surface methodology based on Box-Behnken design was used to optimize the effect of process parameters on product quality. Sensory evaluation of the optimized sample to determine its level of acceptability was carried out as well as the comparison with fried snack from 100% wheat flour. Increasing temperature had significant (P < 0.05) negative effect on the texture. Based on the desirability (0.771) concept, a frying temperature of 140 °C, frying time of 4 min, 32% level of BSCF, and 2 mm thickness was obtained as the optimized conditions. Sensory analyses showed that the optimized sample was preferred in terms of texture and its oiliness to fried snack prepared from 100% wheat flour, but, the aroma, taste and appearance of the wheat snack were preferred.