The Effect of Three Drying Methods on the Physicochemical, Microbiological and Antioxidant Properties of Ginger (Zingiber officinale Roscoe) Sold in Côte d’Ivoire
Gboko Abiba Ouattara *
Department of Biochemistry and Genetics, Laboratory for the Environment, Climate, Health, Engineering and Sustainable Development of Peleforo GON Coulibaly University, Korhogo BP1328, Côte d’Ivoire.
Kouame Maïmouna Liliane
Institute of Agro-Pastoral Management, Biotechnology and Agri-food Valorization Laboratoryof Peleforo GON COULIALY University, Korhogo BP1328, Côte d’Ivoire.
Soumahoro Souleymane
Institute of Agro-Pastoral Management, Biotechnology and Agri-food Valorization Laboratoryof Peleforo GON COULIALY University, Korhogo BP1328, Côte d’Ivoire.
Sako Aminata
Institute of Agro-Pastoral Management, Biotechnology and Agri-food Valorization Laboratoryof Peleforo GON COULIALY University, Korhogo BP1328, Côte d’Ivoire.
Toure Abdoulaye
Department of Biochemistry and Genetics, Laboratory for the Environment, Climate, Health, Engineering and Sustainable Development of Peleforo GON Coulibaly University, Korhogo BP1328, Côte d’Ivoire.
Brou Gboko Konan Gatien
Institute of Agro-Pastoral Management, Biotechnology and Agri-food Valorization Laboratoryof Peleforo GON COULIALY University, Korhogo BP1328, Côte d’Ivoire.
Dabire Constantin Maniénou
Laboratory of Chemistry and Renewable Energy of Nazi Boni University, Bobo-Dioulasso, Burkina Faso.
*Author to whom correspondence should be addressed.
Abstract
Ginger (Zingiber officinale Roscoe) is a spice of economic, culinary, and medicinal importance whose production is attracting increasing interest in Côte d’Ivoire. Its high moisture content in the fresh state makes it highly perishable and susceptible to microbiological deterioration. This study aimed to evaluate the influence of three drying methods on the physicochemical, microbiological, and antioxidant properties of ginger marketed in Côte d’Ivoire. Rhizomes collected from markets in Bouaké, Korhogo, and Koun-Fao were subjected to three treatments: sun drying for 120 h (T1), blanching followed by sun drying for 120 h (T2), and oven drying at 55 °C for 120 h (T3). The dried samples were characterised for moisture content, dry matter, pH, titratable acidity, and ash, as well as for microbiological quality, total phenolic, flavonoid, and condensed tannin contents, and antioxidant activity using the DPPH assay. T3 showed the lowest moisture content (5.56%) and the highest dry matter content (94.4%). Microbiologically, T1 showed high counts of aerobic mesophilic microorganisms (2.3 × 10⁶ CFU/g), Escherichia coli (2.5 × 10⁴ CFU/g), and total coliforms (3.0 × 10⁴ CFU/g). T2 still showed a total coliform count above the retained limit (2.3 × 10⁴ CFU/g), whereas T3 had the lowest aerobic mesophilic count (2.1 × 10⁴ CFU/g) and complied with the retained microbiological thresholds. T1 showed the highest total phenolic content and antioxidant activity, whereas T3 showed the highest flavonoid and condensed tannin contents. Under the conditions of this study, oven drying provided the best compromise between dehydration efficiency and microbiological quality control, while sun drying better preserved some phenolic compounds and overall antioxidant activity.
Keywords: Drying, ginger, physicochemical quality, microbiological quality, phenolic compounds, antioxidant activity