Microbial quality and nutritional assessment of Brassica oleracea (Cabbage) flour processed by sun and oven drying methods

Abstract:

Ensuring the microbial safety and nutritional integrity of vegetable-based flours is critical for their utilization in food systems. This study investigated the effect of sun and oven drying methods on the nutritional composition and microbial quality of flour produced from Brassica oleracea (cabbage). Proximate analysis revealed that oven drying resulted in lower moisture and lipid content but higher protein, fiber, and carbohydrate levels compared to sun drying. Microbial evaluation showed a significantly higher bacterial load (93.00×10⁻³ CFU/mL) and fungal load (75.33×10⁻³ CFU/mL) in sun-dried flour than in oven-dried flour (53.33×10⁻³ and 26.67×10⁻³ CFU/mL, respectively). Isolated microorganisms included Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis, Escherichia coli, Aspergillus niger, Rhizopus stolonifer, and Fusarium oxysporum. The predominance of S. aureus and A. niger in sun-dried samples suggests contamination from handling and environmental exposure. Overall, oven drying yielded safer and nutritionally superior cabbage flour. These findings underscore the need for hygienic and controlled drying methods to enhance the safety and quality of vegetable-derived flours.