Pickling as a Preservation Technique for Solanum aethiopicum; An Edible Green Leafy Vegetable
Sarah Akoth
Department of Food Technology and Nutrition, School of Food Technology, Nutrition and Bioengineering, College of Agricultural and Environmental Sciences, Makerere University, P.O. Box-7062 Kampala, Uganda.
Albert Nuwagira
Department of Food Technology and Nutrition, School of Food Technology, Nutrition and Bioengineering, College of Agricultural and Environmental Sciences, Makerere University, P.O. Box-7062 Kampala, Uganda.
Stellah Byakika
Department of Food Technology and Nutrition, School of Food Technology, Nutrition and Bioengineering, College of Agricultural and Environmental Sciences, Makerere University, P.O. Box-7062 Kampala, Uganda.
Ivan Muzira Mukisa *
Department of Food Technology and Nutrition, School of Food Technology, Nutrition and Bioengineering, College of Agricultural and Environmental Sciences, Makerere University, P.O. Box-7062 Kampala, Uganda.
*Author to whom correspondence should be addressed.
Abstract
Solanum aethiopicum is a nutrient rich green leafy vegetable whose utilisation is limited by its short shelf life. Although refrigeration and freezing are effective methods to preserve vegetables, these methods may not be available and affordable in resource-limited settings. A viable alternative is pickling, which is a cost effective and easy to apply method. In this study, nakati leaves were fermented in brine with 3% dry salt and 2% sugar at 25°C for 14 days. The fermentation was monitored at intervals by enumerating lactic acid bacteria (LAB), coliforms and fungi as well as measuring the brine pH. Sensory evaluation (n=30) was carried out to assess the acceptability of the vegetables. Shelf stability was evaluated for three weeks. The results showed that lactic acid bacteria increased significantly (P < .001) from 2.06 log cfu/ml to 8.2 log cfu/ml during fermentation. Coliforms and fungi reduced from 5.5 log cfu/ml and 1.5 log cfu/ml to undetectable levels within 8 and 6 days of fermentation, respectively. The brine pH decreased from 5.87 at day 0 to 3.35 after 14 days of fermentation (P < .001). Pickled nakati had lower consumer acceptability scores (P < .001) than fresh nakati. The nakati remained stable during the three weeks of storage. Therefore, pickling offers a potentially viable preservation method that can be adopted for green leafy vegetables.
Keywords: Solanum aethiopicum, nakati, pickling, fermentation, vegetables, African eggplant