Effect of Citric Acid Treatment and Fermentation on the Chemical Composition of African Yam Bean (Sphenostylis stenocarpa) and Sensory Evaluation of Its Gruel

Abstract

Aims: Legumes, (especially indigenous/ underutilized legumes), have been found to make substantial contributions to nutrient intakes of the populace especially in low resources environments. The African yam bean (AYB) is one of such indigenous legumes with utilization constraints such as hard-to-cook phenomenon, beany flavour, bitter taste and some anti- nutritional factors that limit its utilization. The aims of this study were to determine effect of citric acid treatment and fermentation on the chemical composition of African yam bean (Sphenostylisstenocarpa) and sensory evaluation of its gruel.
 Methodology: Cream coloured AYB seeds were purchased in Enugu, Enugu State Nigeria. Sorted AYB seeds were washed and fermented in citric acid medium (0.25%, 0.5% and 1%) for 24 h 48 h and 72 h at room temperature (28°C) in a seed water ratio of 1:4 (w/v). The control seeds were fermented without citric acid for 24 h, 48 h and 72 h. After fermentation, each batch of the fermented seeds was divided into two. The first half was dehulled and the other half was left as whole. The fermented seeds were separately dried and milled into flour for further use. Standard methods were used for proximate, mineral and anti-nutrient analyses. Gruels were produced from all the flours and subjected to sensory evaluations using a nine-point hedonic scale. Data obtained were analyzed using a Statistical Package for Social Sciences (SPSS) version 20.0. The analysis of variance (ANOVA) was used to compute the mean and standard deviations. Means were compared using the least significant difference (LSD) and significance accepted at P<.05.
 Results: Chemical compositions of AYB flour fermented in 0.5% citric acid solution showed that protein contents increased by 50%, dietary fibre decreased by 0.02%. Raffinose, stachyose, lectins, trypsin inhibitors, tannins, oxalates, phytates and saponins were all significantly reduced to safe levels. Gruels made from raw and dehulled AYB seeds fermented for 24 h with 0.5% citric acid had higher scores for aroma (7.30 & 7.35, respectively) and general acceptability (7.32 & 7.22, respectively). Dehulled AYB fermented for 24 h in 1% citric acid had the highest score (7.99) for colour. Based on the sensory evaluation results, gruels made from the AYB seeds fermented in 0.5% citric acid compared with the gruels made from AYB seeds that were fermented in tap water. The results showed that gruels made from the AYB seeds that were fermented in 0.5% citric acid for 24 h had higher score for aroma (7.70), colour (7.10) and overall acceptability (7.52). Utilization of AYB in food formulation could be improved by fermenting in 0.5% citric acid solution for 24 h.

Blends of Wheat, Mango Kernel and Orange Pomace Flours: Chemical and Functional Properties

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Effects of Different Fermenting Agents on Proximate Composition and Sensory Evaluation of Masa - A Fermented Puff Fried Batter

“…The improved protein content in LAB and tsamiyan gaye (citric acid) fermented masa may indicate that fermenting masa with lactic acid bacteria (LAB) starter culture may improve it protein content as Olaoye, et al (2017) reported that lactic acid fermentation has been reported to contributes to the safety, health, organoleptic, technological and nutritional qualities of foods. Also Aburime et al (2020) reported that citric fermentation significantly increases the protein contents of foods due to low pH provided by the citric acid thus, facilitating solubilization of protein, resulting in higher protein yields. The crude fibre of the masa samples ranges from 0.37 -0.77% with starter culture fermented masa having highest value.…”

EVALUATION OF CHEMICAL COMPOSITION AND FEEDING VALUE OF FERMENTED JACKFRUIT (Artocapus heterophyllous) SEED MEAL USING RABBITS

“…Effiong et al (2016) noted that an increase in the growth and proliferation of the fungi and bacteria complex in the form of single-cell proteins in 72 hours of cultured rumen digesta filtrate accounted for the apparent increase in the protein content of the I. manni meal. Aburime (2012) reported that fermentation of African yam bean (Sphenostylie stenocardia) in tap water for 24 hours and in lime water for 24 and 48 hours, caused a significant increase in the CP content from 24.19 to 33.08%. The increase in CP contents was also reported by following fermentation of Macrotermes nigeriensis, cassava and mahewu.…”