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

Open Access Journal; Published online: 19 Dec 2018Snack 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

Modeling drying kinetics of fever leaves (Ocimum viride) in a convective hot air dryer

The drying behavior of fever leaves was investigated in a convective hot air dryer with forced convection at a fixed air velocity of 1.5m/s and drying air temperatures of 35, 45, 55 and 65°C. The constant rate period was absent and the drying curve took place in the falling rate period. Experimental data was fitted to six thin-layer drying models – Page, Modified page II, Henderson and Pabis, Modified Henderson and Pabis, Two term and Newton. The performances of the models were investigated by comparing the coefficient of determination (R2), reduced chi-square (÷2) and root mean square error (RMSE) between observed and predicted moisture ratios. The page model showed a good agreement with the data obtained while the effect of drying air temperature on the constants and coefficient of the page model was investigated. The effective diffusivity increases as temperature increases and range between 5.551 x 10-12 – 3.379 x 10-11m2/s while the activation energy was estimated to be 80.78kJ/mol

Effect of Thermo-extrusion Process Parameters on Selected Quality Attributes of Meat Analogue from Mucuna Bean Seed Flour

Flour from mucuna beans (Mucuna pruriens) were used in producing texturized meat analogue using a single screw extruder with the intention to monitor modifications on some functional properties of the extrudate. Response surface methodology based on Box Behnken design at three levels of barrel temperature (110, 120, 130ºC), screw speed (100, 120, 140 rpm) and feed moisture content (44, 47, 50%) were used in 17 runs. Regression models describing the effect of process variables on the product quality attributes were obtained. Result obtained showed that the moisture contents of the meat analogue samples decreased from 13.23 to 6.53%. Increasing feed moisture content resulted in extruded meat analogue with a higher density (0.988), water absorption index (WAI) (2.30), oil absorption index (OAI) (2.350), swelling power (3.47) and lower lateral expansion (0.84). Lateral expansion, OAI and swelling power increased as barrel temperature increased with peak values of 1.39, 2.39 and 3.47 respectively, while bulk density and WAI decreased. The product functional responses with coefficients of determination (R2) ranging between 0.658 and 0.894 were most affected by changes in barrel temperature and feed moisture and to lesser extent by screw speed. Optimization results based on desirability concept indicated that a barrel temperature of 120.15°C, feed moisture of 47% and screw speed of 119.19 rpm would produce meat analogue of preferable functional properties.Keywords: Mucuna bean flour, functional properties, texturized meat analogue, optimization

Evaluation of nutrient and functional properties of doughnut made from the blends of wheat, unripe banana and ginger flours

Background: Most snacks consumed in low income environments do not provide nutrients in adequate quantities needed by the body. Objective: This study evaluated the nutrients  and functional properties of doughnut made from blends of wheat flour (WF), unripe banana flour (UBF) and ginger flour (GF). Methods: The UBF and GF were produced by peeling, drying and milling the unripe banana fruits and ginger roots but WF (Golden penny brand) was purchased at a store. Fourteen blends was generated using d-optimal design. Proximate, vitamins A and C, magnesium, phosphorous, and functional properties of the flour blends were determined. The 14 flour blends were used to produce doughnuts and their proximate composition and sensory evaluation determined. Data were analyzed using SPSS version 16. Analysis of variance and Duncan's Multiple Range test were used to separate and compare means, respectively. Results: The results showed that supplementation significantly (p < 0.05) affected the functional properties of the blends and nutritional contents of the products. Increase in the quantity of unripe banana and ginger flours increased crude fibre, ash, carbohydrate, vitamins and minerals of the blends. A significant increase was observed in the protein and fat contents as the WF increased. Samples 2 and 5 had the highest overall acceptability. Conclusion: The blends containing 95% UBF and 5% GF had a significant increase in the crude fibre and ash contents. There was no significant difference in the sensory rating of doughnuts produced from samples 2 and 5.Key words: Nutrient, functional properties, doughnut,  wheat, unripe banana, ginger flour blends

Quality Attributes of Custard Prepared from Selected Varieties of Sweet Potato Starch Enriched with Soy Protein Isolate

The study investigated the effect of soy protein isolate (SPI) addition on the quality attributes of custard from selected varieties of sweetpotato starch (SPS). Starch was prepared from orange-fleshed sweetpotato (OFSPS) and yellow-fleshed sweetpotato (YFSPS). Simplex lattice design was employed to obtain the various combinations of SPS and SPI. Proximate composition, instrumental colour, functional and pasting properties of the sweetpotato starch and the blends were determined. The sensory attributes of the optimized custard samples with the commercial custard were determined using t-test. The protein and ash contents increased while the fat and carbohydrate contents decreased as the inclusion level of SPI increased in the blends. The addition of SPI significantly decreased (p<0.05) the dispersibility, packed bulk density; peak, trough, breakdown, final and setback viscosities but increased the least gelation concentration, water absorption capacity and swelling power of the blends. There was significant (p< 0.05) difference in the sensory attributes of cooked custard prepared from the optimized blends and the control sample. In conclusion, blending 80% OFSPS with 20% SPI; and 75% YSPS with 25% SPI produced acceptable custard

Effects of Processing Parameters on Physicochemical, Sensory Quality and Acceptability of Yoghurt from Milk of West African Dwarf Goat

Pasteurization, incubation temperature and time are some of the important  processing parameters for the development of fermented dairy products with desired qualities. This study investigated the effect of processing parameters on some physicochemical attributes of yoghurt from milk of West African dwarf goat in order to obtain optimum process parameters and compared some sensory qualities and acceptability of the optimized yoghurt from goat and cow milk yoghurt as control. Response surface methodology (RSM) based on Box Behnken Design was used to optimize the processing parameters; pasteurization temperature (PT; 80 - 85 °C), incubation temperature (IT; 40 - 45 °C) and incubation time (ITm; 2.5 - 4.5 h); while pH, titrable acidity, total solids, fat, protein, viscosity were determined using standard laboratory procedures. Aroma, taste and mouth-feel were monitored for the sensory qualities. Data were analyzed using quadratic polynomial models and analysis of variance. The values for pH, titrable acidity, total solid, viscosity, fat and protein content of goat milk yoghurt ranged from 4.35 - 5.97, 0.57 - 3.70%, 13.54 - 32.64 mg/L, 130158 - 272712 mm2/s, 4.00 - 10.33% and 3.24 - 28.44%; respectively. Optimized WAD goat yoghurt had a sensory rating of 6.07 to 6.37, while cow yoghurt had a rating of 7.73 - 8.20. In conclusion, physicochemical properties of WAD goat milk yoghurt was significantly affected by pasteurization temperature, incubation temperature and time. The optimum processing parameters for WAD goat yoghurt are PT of 84.24oC, IT of 44.22 oC and ITm of 3.8 h, optimized WAD goat milk yoghurt had a higher mean value for its protein content than cow milk yoghurt.Keywords: Goat milk, cow milk, response surface methodology, lactic acid bacteria

Quality Assessment of Vended ‘Pito’ and Safety Practices of Vendors in Different Markets in Ibadan

This study was mainly carried out to assess the quality of street vended ‘Pito’ in some selected markets in Ibadan, Oyo State. The safety of street vending practices was also assessed. The chemical (proximate and physicochemical composition), microbiological and observational check list of eight street vended ‘Pito’ samples collected from four markets (Agbeni, Ogunpa, Beere and Bodija) in Ibadan, Oyo state were investigated. The result showed that street vended ‘Pito’ is significantly (p<0.05) high in moisture, low in protein, ash, fat and carbohydrate. Total coliform, Salmonella spp and Shigella spp were within specification limits of microbiological quality while total viable count (TVC) and total fungi were above the limits. Significant (p<0.05) differences exist among the samples in their chemical composition, microbiological and colour parameters. Keywords: Microbial quality, street vended, ‘pito’ , sorghum based beverage, hygiene practice

Effectiveness of Green Plantain Peel and Pulp Flour Blends as Coating on the Textural Properties and Oil Uptake in Fried Fish Fillets

The aim of this study was to evaluate the effectiveness of green plantain peel and pulp flour blends as coating on the textural properties and oil uptake of fried fish fillet. Plantain peel flour and plantain pulp flour were mixed in ratios 0:100, 5:95, 10:90, 15:85, 20:80, 25:75, 30:70, 40:60, 50:50 and 100:0% peel: pulp, respectively. Fresh fish fillets were coated with the blends of plantain peel and pulp flour, while the uncoated and samples coated with wheat flour served as controls. The results showed that plantain peel and pulp flour blends affected the textural characteristics of the product significantly (p<0.05). The values of hardness, cohesiveness and springiness varied from 0.80-2.6N, 0.19- 0.43, 0.55-0.92, respectively. The lowest value of hardness was observed in sample coated with 100% peel flour. The flour blends were effective in decreasing oil uptake and moisture loss of fried fish fillets than the control samples. Oil uptake of samples coated with 100% peel flour (9.63 %) was significantly lower (p<0.05) than  uncoated (11.49 %). Increasing level of peel flour in the flour blends reduced the oil uptake and moisture loss more effectively than the control sample. Samples coated with plantain peel and pulp flour blends had less shrinkage compared to the uncoated sample. It is concluded that using blends of plantain peel and pulp flour is an effective coating material for fried fish fillet. The plantain peel flour can be incorporated up to 20% in coating formulation without having significant impacton the sensory characteristics on the fried fish fillet.Keywords: Plantain pulp flour, plantain peel flour, quality attributes, deep-fat frying, fish fillets

Deep fat frying of yam slices: optimization of processing conditions using response surface methodology

The deep-fat frying of yam slices was investigated with the aim of optimizing the processing conditions. During frying, frying temperature, initial dry matter and frying time have a significant effect on moisture loss and oil uptake. Response surface methodology central composite rotatable design was used to study the effects of the independent variables on quality attributes of yam chips. Breaking force, oil content, moisture content and color parameters were determined. Statistical analysis with response surface regression showed that breaking force, oil and moisture contents and color parameters (L* and a*) were significantly (P < 0.05) correlated with frying temperature, initial dry matter and frying time. The optimum conditions were a frying temperature of 175–180C, using tubers of initial dry matter of 0.179–0.214 kg/kg with a frying time of 4–5 min. It was suggested that the regression equation can be used to estimate the dependent variables for fried yam chips except b* (yellowness) parameter

Thin layer drying process of some leafy vegetables under open sun

Open sun drying experiments in thin layers of crain-crain (CC), fever (FV) and bitter (BT) leaves grown in Abeokuta, Nigeria were conducted. The drying process took place in the falling rate period and no constant rate period was observed from the drying curves. Eight thin layer mathematical drying models were compared using the multiple determination coefficients (R2), reduced chi-square (χ2) and root mean square error (RMSE) between the observed and predicted moisture ratios. Accordingly, Midilli et al. model satisfactorily described the drying curves of the three leaves with R2 of 0.9980, χ2 of 2.0×10-4 and RMSE of 1.09×10-2 for CC leaves; R2 of 0.9999, χ2 of 2×10-6 and RMSE of 1.11×10-3 for FV leaves; and R2 of 0.9998, χ2 of 1.9×10-5 and RMSE of 3.3×10-3 for BT leaves. The effective diffusivity was found to be 52.91×10-10, 48.72×10-10 and 43.42×10-10 m2s for CC, BT and FV leaves, respectively