Investigating Physicochemical and Sensory Properties of Tomato Paste Using Fennel Seed Extract and Ziziphora clinopodioides Lam. and Predicting the Results Using Artificial Neural Network

This study aimed to produce tomato paste using natural preservatives as an alternative to chemical preservatives. Fennel seed extract (Foeniculum vulgare Mill) and Ziziphora clinopodioides Lam. were used as natural preservatives.Physicochemical properties of tomato paste such as pH, acidity and total soluble solids (Brix) were measured during 5 weeks of storage at 4°C. Sensory properties of tomato paste were assessed using trained and untrained sensory evaluators using a 5-point hedonic scale.To predict the data from an artificial neural network of topology 2-37-1, storage period and different concentrations of fennel seed extract and Ziziphora clinopodioides Lam. were considered as inputs and acidity as the target parameter.The results showed that using different concentrations of fennel seed extract and Ziziphora clinopodioides Lam. significantly reduced (p <0.05) the pH and increased the acidity of tomato paste.Increasing the level of extracts in tomato paste samples significantly (p <0.05) increased Brix during storage period.Sensory evaluation showed that in terms of color, appearance and consistency treatments containing low concentrations of the extracts (0.5 and 1% of both extracts) scored higher.In terms of taste and smell, treatments 3 and 4 (containing 2 and 3% of fennel seed extract, respectively) had the highest score.In general, it can be concluded that using 2 or 3% fennel seed extract as a natural preservative in tomato paste leads to desirable physicochemical and sensory properties.The results of acidity prediction showed that the correlation coefficient and the mean squared error for the total data were 0.99232 and 0.00002, indicating a successful prediction.