Optimising a processing protocol for a safe and vitamin c rich concoction used by Ugandans to alleviate symptoms of COVID-19
Abstract
Background: When the COVID-19 outbreak was declared a pandemic on 12 March, 2020, desperate Ugandans who could not afford exorbitant fees for treatment of COVID-19 resorted to using cannabis and other local herbs to treat the deadly disease. One of the popular concoctions used was a mixture of garlic, lemons, ginger, onion, and red pepper. The main objective of this study is to optimize a processing protocol that preserves the concoction’s vitamin C content while ensuring the product’s microbial safety.
Methodology: The effect of cooking temperature and duration on the concoction’s vitamin C content and the microbial load was optimized using a central composite design and analyzed using response surface methodology. Samples were heated in a randomized model at different water bath temperatures (70 °C, 80 °C, and 90 °C) for different times (5, 10, and 15 minutes). One sample was not heated and was used as the basis for calculating the vitamin C percentage retention in the heated samples. Ascorbic acid content was determined using the 2, 6- dichlorophenol-indophenol titration method described in the Association of Office Analytical Chemists (1996), in which L-ascorbic acid was used to prepare a standard solution (1 mg/mL). For microbial analysis, the total colony counts were determined on plate count agar (PCA) by the pour plate technique. Four additional runs were conducted at 83°C, 5 minutes as a confirmation step for the selected optimal conditions.
Results: The concoction prepared at 70 °C for 5 minutes had the highest percentage retention of vitamin C (70.73%) but it had an unsafe microbial load (126 CFU/ml). The concoction that was prepared at the optimized conditions, 83 °C for 5 minutes, had a vitamin C retention of 69.51% and a microbial load of 0 CFU/ml. Confirmation runs were performed at 83 °C for 5 minutes and the observed responses coincided well with the predicted values given by the optimization technique. The study also showed that both cooking temperature and time had significant impacts on the microbial load and amount of retained vitamin C.
Conclusion: To best preserve the concoction’s vitamin C content and, at the same time ensure a safe microbial load, it should be prepared at 83 °C for 5 minutes.