*3.3. Total Soluble Solids (TSS) and Titratable Acidity (TA) of Fresh and Dried Arils*

The investigated chemical attributes (TSS and TA) in fresh pomegranate arils were significantly (*p* < 0.05) different from those measured after a period of storage (Table 1). For instance, the TSS of fresh aril increased from 13.7 to 15.1 ◦Brix after storage (Table 1), while the TA decreased from 0.38 to 0.24 at 12 weeks' storage. In agreement with our study, Arendse et al. [6] reported that pomegranate cultivar Wonderful stored at 5 ◦C showed an increase in TSS as the storage period progressed. A decrease in TA could be attributed to organic acid break down during the storage period [41]. Fawole and Opara [30] also observed a decrease in TA values for two South African grown cultivars, Bhagwa and Ruby, due to the ongoing metabolism in the fruit during storage.

In dried arils, all chemical attributes showed significant (*p* < 0.0001) interactions with storage period and drying methods (Table 2). Total soluble solids gradually increased with storage period in the hot-air dried arils to almost twice the amount of TSS in freeze-dried arils after storage. The high TSS value could be attributed to drying under high temperature, which resulted in the caramelisation of the product [42].

Throughout the trial, TA was more than double in arils processed with hot-air (3.10–3.15% citric acid) compared to freeze-dried arils (1.14–1.24% citric acid); this could be attributed to the different drying temperatures used (Table 2). Titratable acidity increased after four and eight weeks in hot-air and freeze-dried arils, respectively, before declining with prolonged storage. Ashebir et al. [43] also

noted a significant change in the TSS and TA concentrations of dried tomatoes due to variations in the level of drying temperatures.

The TSS:TA ratio is a good indication of flavour and used as one of the quality indexes of pomegranate fruit [44]. Opposite trends of TSS:TA were observed in dried arils after storage—a slight increase from 7.0 to 7.58 in hot-air dried arils and a significant decrease from 15.4 to 10.2 in freeze-dried arils (Table 2). This implies that storage followed by higher temperature drying enhances the caramelisation and Maillard reaction, breaking down the disaccharides into monosaccharides, and seemingly increasing the TSS content in pomegranate. TSS:TA values ranged between in hot-air dried arils and freeze-dried arils. Higher TSS:TA values observed in freeze-dried arils compared to hot-air dried arils reflect a higher percentage of sugar to acid ratio in dried aril.
