Development and quality characterization of sapodilla ready to serve (RTS) drink

We have been awarded by nature with a stunning flora and fauna that has prettified our life. Sapodilla is well known for its therapeutic and nutritive properties. Sapodilla has good antioxidant mutagenic and anticancer properties that directly influence radical-scavenging potential. Sapodilla has a short shelf life due to its perishable nature. An attempt was carried out to develop sapodilla RTS beverages using sonication and microwave techniques. Physicochemical attributes such as acidity, pH, TSS, pH antioxidant activity of the ready to serve (RTS) and sensory attributes were analysed during 90 days of storage. The highest ° Brix was found in T0 with a mean value of 12.14 ± 1.19° Brix, the highest pH was found in T2 with mean values of 3.82 ± 0.006% and 4.28 ± 0.006% and the lowest pH was observed in T1 with a mean value of 3.72 ± 0.03%. All the treated RTS samples were subjected to antioxidant analysis including total phenols, total flavonoids and total antioxidant activity. The lowest phenolic content was observed in T0 (334.53 ± 1.66 μg GAE/100 mL of juice). The highest total flavonoid content was found in T2 (316.67 ± 19.51 μg CE/g), and the lowest total flavonoid content was observed in T0 (111.48 ± 24.28 μg CE/g). The lowest total antioxidant capacity was observed in T0 (381.85 ± 6.09 μl AAE/ml).The results of sensory evaluation revealed that the maximum score for sensory properties such as color, flavour, taste and overall acceptability was achieved by treatment T2, which revealed that these treatments of sapodilla RTS were declared the best with sonication and microwave treatment.

microorganisms up to 5 logs. Microwaves are cosmic radiation with varying frequencies of 300 MHz-300 GHz. Home microwave ovens normally work at 2.45 GHz frequency, but microwaves in industry work at 915 MHz and 2.45 GHz frequency [11].
The combined effect of these innovative practices proved effective in improving the quality and suitability of fruit juices [12] which is the key objective of this study. Therefore an attempt was carried out to develop sapodilla RTS beverages using combined techniques such as sonication and microwave techniques. To our knowledge, this is the first study that involves the combined effect of US and MW to explore their influence on the stability, quality and physicochemical properties of RTS during storage.

Materials and methods
Good quality fruits of Sapodilla were brought from the local market of Sargodha city, and other raw materials such as sugar, mineral water, citric acid, and plastic bottles were also purchased from the local market of Sargodha, Pakistan. After selection of raw material, the firm, ripen undamaged and healthy sapodilla fruit was sorted and washed out properly with tap water manually. The sapodilla was then peeled, trimmed, depicted and compressed in a juice blender, and the juice was drained using muslin eliminate foreign particles.

Preparation of Sapodilla ready to serve drink
Fruit, sugar, citric acid, and KMS were weighed individually. Sapodilla fruit and all other constituents were assimilated in a blender (Moulinex LM209041 Super Blender) to prepare sapodilla drinks. Recipe of drink mentioned in Table 1 and treatment plan in Table 2.

Ultrasonic treatment
Sonication treatment will be performed after juice formation. An ultrasound processor (UP400S, Hielscher Ultrasonics GmbH Hielscher USA, Inc.) with a power of 750 W and a probe of 0.5 inches was used for sonication of sapodilla at room temperature. Sonication of working juice samples (200 mL in a 500 mL beaker) was performed at 70% amplitude for 5-15 min with pulse times of 5 s on and 5 s off and 20 kHz frequency. Sample preparations and treatments were carried out in triplicate.

Microwave heating
After sonication, the juice was exposed to microwave treatment (Model: DW-128 G, microwave frequency: 2450 MHz, output: 900 W) for 120 s at 90 ℃. The drink was then poured into 200 mL plastic bottles already placed in ice cold water before pouring juice to avoid shrinkage due to heat.

Chemical preservation
Potassium-meta bisulfate is used as a chemical preservative to extend the shelf life of drinks.

Physico-chemical analysis
Total soluble solids were evaluated by a hand refractometer. The pH of the juice was calculated by a pH meter (AD 1040 Benchtop meter, Adwa, Hungary). Acidity was determined by the titration method given in AOAC (2000) using method No. 981, whereas total phenolic compounds total flavonoids and antioxidant activity were measured by the method described by [13].

Sensory evaluation
Sensory characteristics such as color, flavour, texture and overall acceptability of ready-to-serve drinks were analysed at room temperature in a sensory evaluation lab by a panel of 10 untreated judges on 9-points hedonic scale [14].

Statistical analysis
The statistical analysis was performed by using Statistics 8.1 (Analytical Software, Tallahassee, FL, USA). All the data and results acquired from the phytochemicals and physio-chemical attempt were presented as the mean value ± SD. The statistical analysis of these parameters was carried out with ANOVA at a significance level of P < 0.05, and significant differences among the mean values were calculated by the LSD pairwise comparison test [15].

Influence of sonication and microwave on pH and TSS.
There was no significant change seen in the pH of the RTS drink. Correspondingly, an increasing trend was observed after 120 days of storage and in the treatments. Table 3 indicates that the lowest pH was observed in T 0 (3.63 ± 0.14c %) and the highest Ph was observed in T 2 (3.82 ± 0.006c %). After studying it was revealed that the influence of pH during storage increased gradually with the passage of time. Table 3 shows that the lowest value was observed at 0 and storage times, with a mean value of (3.77 ± 0.28%). However, the highest pH was found at 90 days of storage with a mean value of 4.12 ± 0.24. The outcomes of Nguyen et al. (2018) are similar to the above results, who found that the pH of mulberry juice was significantly affected and increased (3.21 ± 0.04 at 30 min and 3.23 ± 0.0 3at 60 min) during storage period comparing sonicated and nonsonicated samples of juice.
The highest Brix was found in T1 (11.25 ± 0.03 Brix). Table 4 shows that the highest values were noticed at 0 and 30 days of storage, with the mean values of (13.32 ± 1.30 and 10.95 ± 1.13° Brix, respectively. However, the lowest ° Brix was found at 90 days of storage with a mean value of 10.53 ± 1.22° Brix. These results are parallel to the outcomes of [16], who observed that there is no significant effect of ultrasonication on total soluble solids for apple juice without consideration of storage period and amplitude levels.

Titratable acidity
The titratable acidity of all the samples was not significantly affected, as a decreasing trend was observed. The highest acidity was found in T1 and T2 (0.087 ± 0.002% and 0.0621 ± 0.004%) and the lowest pH was observed in T2 (0.053 ± 0.001%) The effect of storage duration on the acidity of sapodilla RTS demonstrated that with the passage of storage duration, acidity gradually decreased due to acidic hydrolysis utilizing the acid for the conversion of non-reducing sugars. The highest values were observed at 0 and 30 days of storage with mean values of 0.104 ± 0.003 and 0.092 ± 0.094, respectively. However, the lowest acidity was found at 90 days of storage with a mean value of 0.041 ± 0.003 as shown in Table 5. [17] findings are parallel to the above results, which declare that the titratable acidity of apple juice with carrot and banana juice blends was significantly affected and gradually decreased during the storage period. [16] applied sonication to apple juice and observed a significant decrease in titratable acidity from 0.21 ± 0.05abcd% to.19 ± 0.09d% with increasing sonication time and storage period. The Acidic hydrolysis utilizes acid for the conversion of nonreducing sugars, resulting in a significant decrease in titratable acidity.

Total phenolic and flavonoid content
There was a highly remarkable impact of sonication and microwave treatment was seen on phenolic compounds of RTS drinks. The highest total phenolic content was found in T 2 (370.42 ± 1.88 b μg GAE/100 mL of juice), and the lowest phenolic content was observed in T 0 (343.53 ± 1.66 μg GAE/100 mL of juice). The highest values were observed at 0 and 30 days of storage with mean values of 381.00 ± 14.9 μg GAE/100 mL of juice and 372.08 ± 15.4 GAE/100 mL of juice accordingly. However, the lowest total phenolic contents were found at 90 days of storage with a mean value of 343.08 ± 11.36 μg GAE/g100 mL of juice, as shown in the Table. 6. The sonication time is provided by this longer exposure due to waves generated by ultrasonication, and the phenolic content decreases. The effect of storage duration on the total phenolic contents of sapota RTS demonstrated that with the passage of storage duration, the total phenolic contents gradually decreased. It has been reported that total phenolic compounds increased in grapefruit juice [9], purple cactus pear juice and kasturi lime juice [18] at 60% and 80% amplitude as compared to untreated samples. [20] From these results it was evident that higher values of total phenolics were observed in biscuits having 15% seed powder and the lowest amount of total phenolics was present in the control biscuits. The total flavonoid content of sapodilla RTS ranged from 111.48 ± 24.28 μg CE/g to 492.59 ± 30.93 μg CE/g. Table 7 shows the influence of treatment on the total flavonoid contents, The highest total flavonoid content was found in T 2 (316.67 ± 19.51 μg CE/g), and the lowest total flavonoid content was observed in T 0 (111.48 ± 24.28 μg CE/g). The total flavonoid contents of all samples significantly decreased with increasing temperature. The effect of storage duration on the total flavonoid contents of sapodilla RTS demonstrated that with the passage of storage duration, total flavonoid contents gradually decreased. Observed a significant decrease in flavonoid contents by increase in a temperature (as the degradation of flavonoids) Table 7 shows that the highest values were observed at 0 and 30 days of storage with mean values of 459.26 ± 208.35 μg CE/g and 335.19 ± 173.80 μg CE/g respectively, as shown in Table 7. [18] reported that if we increase the storage time period for ultrasonically conducted plum drinks the TF decreases. Ultrasound-treated kasturi lime and Chokanan mango juice also gave the highest range when ultrasound was used [19].

Total antioxidant activity (TAC)
A highly significant impact of sonication and microwaves was observed on the total antioxidant activity of RTS drinks during storage. Table 8 showed the influence of treatments on total antioxidant capacity, the highest antioxidant capacity was found in T 2 (410.68 ± 5.10 μl AAE/ml) and the lowest total antioxidant capacity was observed in T 0 (381.85 ± 6.09 μl AAE/ml).The antioxidant values of all samples significantly increased with increasing in sonication time. The effect of storage duration on total antioxidant capacity of Sapodilla RTS demonstrated that with the passage of storage duration, the total antioxidant capacity gradually decreased. Table 8 shows that the highest values were observed at 0 and 30 days of storage with mean values of 557.69 ± 4.98 μl AAE/mL and 448.28 ± 5.44 μl AAE/mL respectively. However, the lowest antioxidant capacity was found at 90 days of storage with a mean value of 235.07 ± 4.08 μl AAE/mL as shown in Table 8. The increase in TAC might be attributed to ultrasonic treatment because this technology enhanced the activity of bound antioxidants such as total phenols, flavonoids and ascorbic acid leading to increased total antioxidant capacity. Moreover enzymes were deactivated by ultrasonic treatment such as polyphenol oxidases which are responsible for enzymatic browning through which TAC improved. The study of [16] evaluated the decreasing trend while storing TAC of sonication at various times. Such an elevation in the capacity of antioxidants while cavitation was produced; was also related to the availability of such phytochemical constituents.

Sensory evaluation
The results reveal that properties such as color, flavor, taste, and overall acceptability may be achieved by the treatment methods of sonication and microwave treatment.

Conclusion
A study was carried out to investigate the impact of sonication and microwave treatments on the physicochemical attributes of sapodilla drinks during storage for three months. It was discovered that these techniques enhance the antioxidant, and physicochemical properties and shelf life of Sapodilla RTS by inactivating the enzymes and spoilage microorganisms. Among all the treatments, the T2 sample proved best regarding the quality and shelf life of RTS. It causes minimal loss of nutrients, phytochemicals, juice color, bioactive compounds and other available components. These techniques could be used as an alternative to other nonthermal techniques and chemical preservatives on fruit-based items to maintain quality characteristics and shelf life.