Physicochemical analysis
Total sugars (%)
In this explored investigation, our attention is drawn to the indispensable role of sugars in fruit products, specifically influencing flavor development and preservation. The examination delves into the dynamics of total sugar concentration (%) in diverse jam samples over the storage period. The standard jam commences with an initial total sugar content of 63.19%, culminating at 67.78% during storage. Among fresh samples, T
12 manifests the highest mean total sugar content (15.82%), while T
1 registers the lowest (12.45%) (Table 2). Noteworthy increments occur during storage, with T
1 and T
12 reaching 16.78% and 19.79%, respectively. The incorporation of gum tragacanth and chia seeds in low-calorie papaya jam induces significant alterations in total sugar content (p<0.05) during treatment and storage. Naturally, the standard jam, enriched with sucrose, attains the highest mean total sugar level. The escalation in total sugar content is ascribed to the conversion of starch and other insoluble carbohydrates into sugars, aligning with prior studies by
Sutwal et al., (2019), Pinandoyo and Masnar (2020) and
Kumar et al., (2020) focusing on apple and papaya jams, respectively.
Reducing sugar (%)
In this investigation, a noteworthy increase (p<0.05) in reducing sugars (%) was evident in all jam samples over time (Table 2). Notably, the mean reducing sugar content for the standard sample, T19, elevated from 21.77% to 24.89%. Particularly, sample T
1 exhibited an increase from 5.94% to 8.50%and sample T
12 from 7.50% to 11.88% during storage. The rise in reducing sugars in standard jam is attributed to sucrose inversion in an acidic environment, where sucrose transforms into glucose and fructose due to acidity and prolonged storage. This observation aligns with
Sutwal et al., (2019), who noted a significant increase in apple jam’s reducing sugar content during storage. Similar findings were reported by
Pinandoyo and Masnar (2020) and
Kosiorowska et al., (2022) in papaya jam fortified with soya proteinand cranberry jams with added gold flax and chia seeds, respectively. These consistent results underscore the impact of storage conditions on jam composition and align with existing literature.
pH
In the investigation of pH’s impact on gel formation in papaya jam, the addition of chia seeds and gum tragacanth significantly influenced pH levels throughout treatments and storage (p<0.05). Initial pH for the standard sample was 3.95%, gradually decreased to 3.22% over six-month storage. All samples exhibited a decline in pH over time, with initial readings for T
1 and T
12 at 3.83% and 4.56%, respectively. During storage, these values decreased to 3.10% and 3.83%, indicating an average pH drop. The acidic content increase, possibly due to sugar breakdown or polysaccharide hydrolysis, contributed to this decline.
Anwar et al., (2023) and
Basu and Singha (2023) reported similar pH reductions in papaya jam during storage, reinforcing the findings. This underscores the importance of pH control for optimal jam quality (Table 2).
Ascorbic acid (mg/100 g)
The incorporation of gum tragacanth and chia seeds exhibited a significant impact (p<0.05) on preserving ascorbic acid (mg/100 g) in papaya jam during treatments and storage. The mean ascorbic acid content for the standard sample (T
19) decreased from 26.95 mg/100 g to 22.44 mg/100 g over the storage. As evidenced in Table 3, initial ascorbic acid content in samples T
1 and T
12 was 26.10 mg/100 g and 33.47 mg/100g, gradually decreasing to 21.70 mg/100 g and 28.96 mg/100 g, respectively during storage. This decline may result from ascorbic acid oxidation, leading to dehydroascorbic acid and subsequent degradation into 2, 3-diketo-l-gulonic acid and furfural compounds. The results aligns with the findings of
Kumar et al., (2020) and
Pourashouri et al., (2021) who observed reductions in ascorbic acid content in guava-papaya jam over time and low-calorie fruit nectars incorporating stevioside as a natural sweetener.
Titratable acidity (%)
In Table 3, the impact of gum tragacanth and chia seeds on titratable acidity (%) in low-calorie papaya jam is detailed. The addition of chia seeds and gum tragacanth significantly altered acidity (p<0.05) during storage and treatments. Initial acidity levels of T
1 and T
12 samples were 0.65% and 0.30%, respectively, gradually rising to 0.69% and 0.34%, respectively. This rise may stem from organic acids formed through polysaccharide breakdown, aligning with
Sutwal et al., (2019), who observed increased acidity in apple jam over 28 daysand similar trends in strawberry marmalade (
Özbek et al., 2019) and sugar-free sea buckthorn marmalades
(Nistor et al., 2021).
Total soluble solid (TSS) (ºB)
Incorporating gum tragacanth and chia seeds into papaya jam significantly altered the TSS content during treatment and storage (p<0.05) (Table 3). The total soluble solids (TSS) data indicated minor alterations during room temperature storage, with an overall increase in TSS over time. The total soluble solids (TSS) of the standard jam were recorded as 68.05 °B. The sample T
12 exhibited the highest mean value (27.10 °B) compared to T
1 (21.15 ºB), attributed to the higher sugar concentration in standard jam. The rise in total soluble solids may result from acid-induced polysaccharide breakdown into simple sugars during storage, releasing soluble sugars in the product. These findings align with previous studies on pineapple jam, strawberry marmaladeand sour cherry jam, highlighting the impact of added components on TSS dynamics during storage
(Nduko et al., 2018; Özbek et al., 2019;
Nourmohammadi et al., 2021).
Texture analysis
Firmness and cohesiveness
In the investigation of low-calorie papaya jam, the incorporation of gum tragacanth and chia seeds significantly influenced (p<0.05) firmness and cohesiveness, as illustrated in Fig 2 and Fig 3. The firmness of fresh samples (6.90 N–7.71 N) increased to 7.02 N-7.83 N over the storage period, aligning with the findings of
Shokraneh et al., (2023), indicating improved structure with fiber substitution. Cohesiveness, ranging from 0.78 N-0.85 N initially, increased to 0.88 N-0.95 N during storage due to incorporation of gum tragacanth and chia seeds. Similar findings were reported by
Nejatian et al., (2019) and
Özbek et al., (2019) in low-calorie dairy desserts and strawberry marmalade, respectively. These results highlight the positive impact of fiber on texture attributes, echoing similar findings in related studies
(Ghasemi et al., 2017).
Organoleptic analysis
Overall acceptability
During the six-month storage period, the overall acceptability of all jam samples declined significantly (p<0.05). The overall acceptability of standard sample decreased from 8.25 to 6.68 during storage period. For the samples, T
1 had an initial acceptability of 7.63, decreasing to 5.68 and T
12 had 8.38, declining to 7.12 over time (Fig 4). The reduction in organoleptic quality parameter which includes color, aroma, flavor and taste with prolonged storage reflected the decline in overall acceptability, consistent with the findings of
Sutwal et al., (2019) and
Kumar et al., (2020) who observed similar trends in apple jam and guava-papaya jam, respectively.