Evaluation of some phytochemicals in raw and cooked Ipomea batatas (Lam), (Sweet potato), Solanum tuberosum (Irish potato) and Dioscorea cayenensis (Yellow yam)

Cooking induces numerous phytochemical changes in food. This study is aimed at determining the amount of phytochemicals present in raw and cooked sweet potato, Irish potato and yellow yam. The amount of tannin, alkaloids, saponin, flavonoids and phenol were determined in raw and cooked samples of each food crop. The result showed that tannin, alkaloids, saponin, flavonoids, phenol contents was high in Irish potato and sweet potato but was far much present in Irish potato, while it was seen in minute quantity in yellow yam. The values obtained for each phytochemicals in each food sample raw and cooked respectively, in mg/100g were; Yellow yam: Tannins (0.10 and Nil), Alkaloids (2.00 and 0.51), Flavonoids (1.18 and 0.87), Saponins (2.00 and 1.02) and Phenols (0.72 and 0.10). Sweet potato: Tannins (0.32 and 0.28), Alkaloids (2.17 and 0.62), Saponins (2.10 and1.58), Flavonoids (1.28 and 0.97) and Phenols (1.42 and 0.72). Irish potato: Tannins (0.55 and 0.49), Alkaloids (2.17 and 0.81), Saponins (4.00 and 2.13), Flavonoids (5.00 and 2.91) and Phenols (2.00 and 0.91). The % loss of phytochemicals after cooking were; Yellow yam: Tannins (Nil), Alkaloids (74.5), Saponins (49.0), Flavonoids (26.3) and Phenols (86.1). Sweet potato: Tannins (12.5), Alkaloids (71.4), Saponins (24.8), Flavonoids (24.2) and Phenols (49.3). Irish potato: Tannins (10.0), Alkaloids (62.7), Saponins (46.8), Flavonoids (41.8) and Phenols (54.5). These results indicate that boiling of the samples seems to reduce their phytochemical contents as the raw samples showed higher amounts of the phytochemicals. The results also revealed that Tannins are more stable to heat across the 3 food samples, followed by Flavonoids, Saponins, Phenols and Alkaloids. The loss in some of the phytochemicals after cooking did not significantly affect the nutritional quality of the food samples.

Étude de la stabilité de quelques propriétés physicochimiques des tranches d’igname congelées (Dioscorea cayenensis-rotundata cv Kponan) de Côte d’Ivoire et analyse sensorielle des mets dérivés

Objectif : Évaluer l’impact de la congélation sur certains paramètres physico-chimiques des tranches d’ignames de la variété kponan et faire une analyse sensorielle de quelques mets dérivés. Méthodologie et résultats : L’étude a été faite sur des tranches d’ignames prétraitées puis congelées pendant 3 mois. À Chaque mois, des échantillons ont été prélevés pour une analyse des paramètres physicochimiques et sensorielle des mets dérivés. La congélation n’a pas eu d’effet sur les teneurs en fibre, en protéine et en cendre. Cependant, au cours du premier mois, la matière sèche a augmenté de 5,59 %. Une augmentation des sucres réducteurs a été également observée. Tandis que la teneur en amidon a diminué de 5,54 %. A partir du deuxième mois, tous les paramètres physico-chimiques étudiés sont demeurés stables. Le profil sensoriel des mets dérivés a montré une bonne appréciation des caractéristiques sensorielles avec une forte élasticité (foutou) et une augmentation de la croustillance, de la fermeté et de la couleur (frite). Conclusion et applications des résultats : La technologie utilisée au cours de cette étude a permis de conserver la majeure partie des caractéristiques physico-chimiques et sensorielles de l’igname durant 3 mois. La production de tranches d’igname congelées doit être envisagée afin de palier le problème de conservation post-récolte, assurer la disponibilité tout au long de l’année permettant d’assurer la sécurité alimentaire et contribuer ainsi à la lutte contre la pauvreté en milieu rurale. Coulibaly et al., J. Appl. Biosci. 2021 Étude de la stabilité de quelques propriétés physico-chimiques des tranches d’igname congelées (Dioscorea cayenensis-rotundata cv Kponan) de Côte d’Ivoire et analyse sensorielle des mets dérivés 16322 Study of the stability of some physicochemical properties of frozen yam slices (Dioscorea cayenensis-rotundata CV Kponan) from Côte d'Ivoire and sensory analysis of derived dishes ABSTRACT Objective: Evaluate the impact of freezing on certain physicochemical parameters of yam slices of the kponan variety and make a sensory analysis of some derived dishes. Methodology and results: The study was performed on slices of pretreated yams and then frozen for 3 months. Each month, samples were taken for an analysis of the physico-chemical and sensory parameters of the derivative dishes. Freezing did not affect fiber, protein, and ash contents. However, in the first month, dry matter increased by 5.59%. An increase in reducing sugars was also observed. While the starch content decreased by 5.54%. From the second month, all the physico-chemical parameters studied remained stable. The sensory profile of the derived dishes showed a good appreciation of the sensory characteristics with high elasticity (foutou) and an increase in crispness, firmness, and color (fried). Conclusion and application of the results: The technology used during this study made it possible to conserve most of the physico-chemical and sensory characteristics of the yam for 3 months. The production of frozen yam slices should be considered in order to overcome the post-harvest conservation problem, ensure availability throughout the year, ensuring food security and thus contributing to the fight against poverty in the environment. rural.

PATHOGENIC APTITUDES OF THREE Yam Mosaic Virus (YMV) GENETIC GROUPS RESPONSIBLE FOR YAMS VIRAL DISEASES OF THE COMPLEX Dioscorea cayenensis-rotundata IN TOGO

This work was aimed to study the pathogenicity of genetic groups of yam mosaic virus (YMV) infecting Dioscorea cayenensis-rotundata in Togo. The virulence and aggressiveness of six YMV isolates (P3-20, C9-25, S2-21, M9-30, K9-5, P8-15) belonging to three genetic groups, were evaluated at the seedlings stage of three accessions of D. cayenensis-rotundata. These isolates were collected from the five yam-producing regions of Togo. For testing virulence and aggressiveness, two isolates per genetic group were mechanically inoculated to ten yam seedlings (five seedlings in two repetitions) per accession. Positive accessions were used to transmit YMV with the help of insect vector Aphis craccivora. RT-PCR test was performed to detect the presence of YMV in yam seedlings using two primers viz., YMV1 & YMV2 (196 bp). The results of the study revealed that all six YMV isolates were able to infect the three yam accessions. A significant difference (p = 0.05) was observed in the aggressiveness of the selected six isolates which clustered into three aggressiveness levels: group 1 included isolate P3-20 which was reported as very aggressive, group 2 have three isolates viz., S2-21, M9-30, K9-5 which considered as a moderately aggressive while group 3 have rest two isolates C9-25, P8-15 with a low level of aggressiveness. However, apart from isolates S2-21and M9-30 belonging to the same genetic and aggressiveness group, most of the isolates from the same genetic group had different levels of aggressiveness; suggesting that the variability in pathogenicity of these isolates was not, at first blush, related to the genetic variability of the virus. Also, it was reported that isolate S2-21 could not transfer through the vector A. craccivora. Results of the study suggested that among the tested YMV isolates, P3-20 was highly pathogenic while S2-21 and M9-30 were reported moderately pathogenic.

Dioscorea cayenensis (Guinea yam).

Dioscorea cayenensis, one of the cultivated tropical species of Dioscorea, is an important staple in Africa, with 2500 cultivars developed. It is a vine mostly known from cultivation, but also reported as escaped in the Panama Canal Zone. In Cuba, it is listed as a transformer species with a high possibility of becoming invasive, although there are no further details. The infrequently reported sexual reproduction, the digging of the tubers and its strict environmental requirements limit the spread of this species.

Estimation of Phytochemical in Yam Flours and Sensory Attribute of Poundo Yam Produced from Yam and Moringa oleifera Seed Meal Blends

The sensory characteristic can be quantified and defined by the use of the descriptive profile. A different cultivar of yam can be used for the production of poundo yam. The standard of a product is determined by the evaluation and its acceptability by a taste panelist. Four cultivars of yam; Dioscorea alata, Dioscorea cayenensis, Dioscorea rotundata and Dioscorea bulbifera were sourced and processed into flour. Moringa seed oleifera was defatted and the cake was blended at a different concentration of 5% and 10% with the yam flour. The qualitative phytochemical investigation of the yam flour and Moringa oleifera seed revealed the presence of, alkaloids, steroids, terpenoid oxalate, anthraquinone, phenol, saponins, tannins and flavonoids. Quantitative analysis showed that among the control samples Dioscorea alata (DAC), Dioscorea Dioscorea bulbifera (DBC), cayenensis (DCC) and Dioscorea rotundata (DRC). DRC and DAC have the highest values in the total phenol and total flavonoids. Dioscorea cayenensis recorded the highest value in steroid and saponin content. The flavonoids, steroid and terpenoid were improved by the inclusion of moringa seed meal at 5% and 10%. The result of the sensory analysis revealed that panellist preferred DRC in term of moldability, texture, taste and general acceptability. However, the samples with moringa seed meal at 5% and 10% inclusion compete favourably with the control samples. The inclusion of Moringa oleifera seed meal at 10% improved the pounded yam and was more accepted than the 5% in term of general acceptability.