A Comparative Study of Preservative Potential of Ginger and Bitter Kola for Tomato Preservation

Tomatoes are preserved to extend their shelf life and prevent wastage due to their high-water content and perishable nature. Using plant extracts as preservatives offers several benefits, such as keeping tomatoes free from chemicals and their associated long-term health risks, while enhancing tomato antioxidant and antimicrobial properties, but maintaining tomatoes nutrients, and having minimal effects on tomatoes overall quality. This study examined the potential of ginger and bitter kola extracts as natural preservatives for tomatoes. Ripe tomatoes were soaked in hot water extracts of ginger, bitter kola, and a combination of both, referred to as GE, BKE, and GBE, respectively. The tomatoes were monitored daily for signs of decay and weight loss while glucose, fructose, potassium, total solids, citric acid, and ascorbic acid levels were measured on days 6, 18, and 29 for the 30-day period of the experiment. Between days 0 and 6, all samples showed weight loss, colour changes, and loss of firmness. From days 6 to 29, glucose remained relatively stable in GE (7.5–7.57 mg/100g) and BKE (7.5–8.21 mg/100g), but it decreased in GBE (9.4–6.54 mg/100g). Ascorbic acid levels remained fairly stable in BKE (28.52–27.04 mg/100g), but decreased significantly in GE (32.45–15.24 mg/100g) and GBE (43.76–17.05 mg/100g). Fructose loss was most pronounced in GE (3.4–2.43 mg/100g), followed by GBE (3.95–3.63 mg/100g) and BKE (3.35–2.9 mg/100g). The results indicated that bitter kola showed potential for preserving tomato quality though there were challenges related to nutrient loss and microbial resistance.