Effect of processing methods on functional, pasting properties of flours and sensory evaluation of “Amala” made from different yam cultivars

Abstract

The effect of processing methods on the functional, pasting properties of flours and sensory evaluation of “amala” made from three different cultivars of yam were determined using standard analytical methods. The three cultivars of yam namely; Dioscorea caynensis “Amula and Lasinrin) and Dioscorea alata (Cote divoire) were processed using three different methods as following; (a) parboiling with steep water (omi-ogi) in aluminium pot and local clay pot (b) parboiling with clean water in aluminium pot and local clay pot (c) heating steep water omi -ogi and clean water separately at 60°C and blanching sliced yam with it in plastic bucket. The functional and sensory properties of the yam flour obtained from the three processing methods were determined using standard analytical method. Data collected were analyzed statistically to determine the Analysis of Variance (ANOVA) and the means. There were significant differences (P<0.05) in the result obtained. The bulk density, water absorption capacity, wettability, oil absorption capacity and swelling index of the yam flour ranged from 0.33±0.01 to 0.49±0.03g/ml, 7.50±0.44 to 0.50±0.44g/ml, 36.67±11.55 to 178.33±2.89secs, 1.47±0.23 to 7.40±1.06g/ml and 1.10±0.01 to 1.82±0.03g/g respectively. The peak viscosity, trough, breakdown, final viscosity, setback, peak time and pasting temperature of yam flour ranged from 1783.00±7.07 to 3682.00±2.83 cP, 1691.00±4.24 to 3533.50±3.54cP, 27.50±2.12 to 195.00±7.07cP, 2351.00±1.41 to 4332.50±3.54cP, 420.00±7.07 to 799.00±1.41cP, 7.03±0.04 to 5.10±0.14cP, 81.35±0.92 to 89.10±0.14cP respectively. The appearance, colour, taste, texture and overall acceptability of the “amala” ranged from 3.70±1.08 to 8.65±0.75, 3.70±1.03 to 8.60±0.82, 3.50±1.19 to 8.20±1.01, 3.35±1.04 to 8.50±0.95 and 3.35±0.75 to 8.60±0.75 respectively. The LLPSW (cultivar “Lasinrin” processed with local clay pot and steep water “omi-ogi”) had the highest water absorption capacity, LAPOW (cultivar “Amula” processed with aluminium pot and clean water) had the best overall acceptability. Water absorption capacity measures the extent of water retention in yam flour. It can be concluded that yam flour processed with LCPSW was the best flour from the above results on water absorption capacity.

Evaluation of the Physicochemical and Sensory Properties of Yam-Based Semolina Fortified with Orange-Fleshed Sweet Potato and Beetroot Flours

“…The final viscosity of the composite semolina sample was 338.92 RVU. The value obtained is lower compared to the values (2464 -4332 cP) reported by Olarenwaju et al (2021) for semolina produced from different yam cultivars. The difference might be as a result of variations in the product formulation.…”

“…Pasting properties of semolina from blends of 80 % yam, 10 % orange fleshed sweet potato and 10 % beetroot flours.Peak viscosity of the semolina sample was 268.17 RVU. The results obtained in this study fell within the range reported byOlarenwaju et al (2021) who reported values ranging from 1783 -3682 RVU for flours prepared from different yam species; but lower than the values (915 -1789 RVU) reported by…”

“…As shown in Table 2, the bulk density of the formulated semolina was 0.668 g/cm 3 . This value falls within the range of 0.56 -0.84 g/cm 3 reported by Olu et al (2012) for soy-poundo yam flour but higher than 0.33 -0.49 g/cm 3 reported by Olarenwaju et al (2021) for flours produced from different species of yam. Bulk density according to Kraithong et al (2018) is a determinant of food expansion and an indication of the porosity of food products.…”

“…The setback viscosity gives an idea of the retrogradation tendency of starch in the flour sample after 50°C (Ohizua et al, 2017). Higher setback value means reduced dough digestibility while lower setback during cooling of paste indicates lower tendency for retrogradation (Olarenwaju et al, 2021). The value for setback viscosity obtained in this study was 133.03 RVU.…”

“…Final viscosity is defined as the quality of particular starch-based flour ability to form a viscous paste after cooking and cooling (Bamidele et al, 2015). Olarenwaju et al (2021) have reported the use of starches with high viscosity value in pharmaceutical companies especially as tablet binders.…”