Indigenous additives: effects on the physico-chemical and sensory properties of fermented yam flour and its product- <i>amala</i>

Abstract

The inclusion of indigenous additives during the processing of elubo (fermented yam flour) has been alleged to result in high quality amala (reconstituted fermented yam flour) by improving its colour characteristics, which is a major quality index of amala, and other sensory attributes. Therefore, this study was conducted to determine the effect of indigenous food additives on the colour and chemical properties of elubo and the sensory properties of amala. Five (5) batches of Elubo were processed from Dioscorea rotundata var. atoja with indigenous additives (ewe okan, popooro oka, omikan and ewe abafe) and a control sample with no additive. Amala samples were prepared from the elubo samples using standard method. The chemical properties (proximate composition, pH, starch and sugar content) of the elubo; colour parameters: L* (lightness), a* (red-green axis) and b* (yellow-blue axis) of elubo and amala; and sensory evaluation properties of amala were determined using standard procedures. The study showed that indigenous additives had significant (p<0.05) effect on the pH, ash content, crude fat and starch content. The results of the colour parameters showed that L* and b* values of the elubo samples without additives were the highest (92.22) and lowest (11.92) respectively, as the samples with additives had reduced L* values ranging between 87.71 to 75.37 and increased b* values of 12.46 to 13.68 respectively. The additives had significant effect on the L* (46.78 to 52.90), a* (3.49 – 6.08) and b* (9.04 – 13.12) values of the amala samples. There were also significant (P<0.05) effects of the additives on the sensory properties of amala. Hence, the selected additives used in processing of fermented yam flour (elubo) had significant impact on the sensory attributes and colour parameters of the fermented yam flour and its resulting product (amala), but no significant effect on most of the chemical properties.