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BACKGROUND: Kponan is the most popular yam (Dioscorea cayenensis-rotundata) variety in Côte d'Ivoire. Unfortunately, losses due to rotting during storage do not ensure a regular supply to markets. This study aimed to identify the impacts of cultivation and storage practices in the main production areas on physical, cooking and sensory characteristics of Kponan. To this end, yams grown in Bondoukou were stored in straw huts, those grown in Bouna in pits and those grown in Kouassi-Kouassikro in the open air, according to the practices of each producer. RESULTS: Findings showed that yams grown in Kouassi-Kouassikro and stored in the open air recorded the highest rot rate (58.09%) compared to the rot rate of yams grown and stored in pits in Bouna (26.67%) and those grown and stored in straw huts in Bondoukou (53.34%). However, the weight losses were respectively 10.47% (Bouna), 28.57% (Kouassi-Kouassikro) and 36.19% (Bondoukou). Loss rates varied significantly from 43.80% (pits) to 100% (huts and open air). Furthermore, the browning indices were higher for yams grown in Kouassi-Kouassikro and freshly harvested (26.09) compared to the browning index recorded for yams grown and freshly harvested in Bouna (23.43) and in Bondoukou (24.73). Concerning the hardness of yams, it decreased during storage for yams grown and stored in pits in Bouna (38.94 to 25.20 N) and for those grown and stored in straw huts in Bondoukou (39. 39 to 26.42 N). CONCLUSION: The shelf life and culinary and sensory characteristics of Kponan depend on the cultivation and storage practices of each producer. © 2023 Society of Chemical Industry.

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Attiéké, the most widely consumed cassava product in Côte d'Ivoire, has a short shelf life. This is largely due to microbial contamination. The aim of this study was therefore to assess the antioxidant activity and effectiveness of Garcinia kola seed oil against pathogenic and spoilage strains of attiéké. This was possible through an extraction of Garcinia kola oil by maceration in hexane. The antimicrobial activity of the oil was assessed using an agar diffusion method. The antioxidant activity of Garcinia kola oil was assessed using the DiPhenyl Picryl Hydrazyl (DPPH) free radical scavenging test and the Ferric Reducing Antioxidant Power (FRAP) test. Garcinia kola oil showed significant antioxidant potential. A high percentage of DPPH radical inhibition was observed, with an IC50 of 2.57 mg/mL. Iron-reducing power was highest when the oil was used at a concentration of 100 %. Garcinia kola oil was able to inhibit the bacterial growth of Staphylococcus aureus, Escherichia coli at a concentration of 100, 50 and 25 % respectively from 22 ± 0.05 to 16 ± 0.00 mm and 20 ± 0.05 to 14 ± 0.08 mm and Salmonella typhimurium (12 ± 00 mm) at a concentration of 100 %. Candida albicans (20 ± 0.07 to 18 ± 0.01 mm), Aspergillus flavus (28 ± 1.41 to 16 ± 0.00 mm) and Aspergillus niger (21 ± 1.01 to 15 ± 0.02) were inhibited at concentrations ranging from 100 to 12.5 %. Bacillus cereus, on the other hand, was resistant to Garcinia kola oil. Based on the findings of this study, Garcinia kola seed oil could be used to extend the shelf life of attiéké.

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Hibiscus sabdariffa is a tropical plant with red calyxes whose anthocyanins, phenols, and antioxidant activity make it attractive to consumers both from a nutritional and medicinal standpoint. Its seasonality, perishability, and anthocyanin instability, led to the setup of stabilization methods comprising drying and powdering. However, its properties can often be altered during these stabilization processes. Treatments such as dehumidified-air-drying, infrared drying, and oven-drying, and their combination showed better quality preservation. Moreover, powder production enables superior biomolecule extractability which can be linked to a higher bioaccessibility. However, the required temperatures for powder production increase the bioactive molecules degradation leading to their antioxidant activity loss. To overcome this issue, ambient or cryogenic grinding could be an excellent method to improve the biomolecule bioavailability and accessibility if the processing steps are well mastered. To be sure to benefit from the final nutritional quality of the powder, such as the antioxidant activity of biomolecules, powders have to offer excellent reconstitutability which is linked to powder physicochemical properties and the reconstitution media. Typically, the finest powder granulometry and using an agitated low-temperature reconstitution media allow for improving anthocyanin extractability and stability. In this review, the relevant physicochemical and processing parameters influencing plant powder features from processing transformation to reconstitution will be presented with a focus on bioactive molecules and antioxidant activity preservation.

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Total starch (TS) and resistant starch (RS) contents in pasty edible product of mealy and hard cooking tubers of three yam varieties and four cassava varieties were determined to evaluate their contribution in their cooking quality. TS and RS contents appeared as the main components in determining yam cooking quality. Mealy cooking yam varieties were characterized by a significant higher TS content (75.2 ± 7.7 g/100 g d.m.) and lower RS content (13.8 ± 3.4 g/100 g d.m.) than hard cooking yam varieties, which, in contrast, contained less TS (61.7 ± 12.1 g/100 g d.m.) and particularly high RS (21.8 ± 9.9 g/100 g d.m.), possibly as a consequence of the prevalence of large granules (35-40 µm) observed by light microscope. Conversely, TS and RS contents appeared not determinant on the cooking quality of cassava. Moreover, higher amylose contents were associated with substantially elevated percentages of RS in yam and cassava, and high RS content in samples modulates their pasting properties by reducing the peak viscosity and the breakdown and requiring higher temperature and longer time to the peak.

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