The evolution of chemical composition of PJ during fruit developmental
stages is shown in Table 1. Fruit maturity had a significant
(Pb0.05) effect on all parameters studied along the days after full
bloom (DAFB). Juice content was 29.31% at 54 DAFB and reached
54.93% at full-ripe stage. Previous studies have reported juice content
ranging between 25 and 45% during pomegranate fruit developmental
stages of the ‘Wonderful’ pomegranate cultivar (Shulman et al.,
1984). There was a steady increase in absorbance as juice color
changed from white to pink between 54 and 110 DAFB, and then increased
sharply as the color changed from pink to deep red (Fig 1).
The overall increase in juice absorbance during fruit developmental
stages is largely as a result of the accumulation of anthocyanins
(Shulman et al., 1984).
Total soluble solids (TSS) content increased significantly during fruit
development with approximately 1.5-fold increase from 54 DAFB to
165 DAFB (Table 1). The TSS found in fully ripened fruits averaging
16.2 °Brix was higher than 15.3% reported by Kulkami and Aradhya
(2005) for the ‘Ganesh’ cultivar grown in India. According to Ben-Arie
et al. (1984), pomegranate fruit of ‘Wonderful’ cultivar grown in Israel
attained optimumqualitywhen the TSS of the fruit reached 15%. The increase
in TSS could be attributed to the hydrolysis of starch to sugars as
pomegranate fruit advancing maturity (Kulkami and Aradhya, 2005).
On the contrary, fruit titratable acidity initially decreased sharply
in late immature stage (82 DAFB) then followed by a continuous
but slow decrease with advancing fruit maturity (Table 1). Titratable
acidity (TA) ranged from 0.62 to 0.38% (tartaric acid), representing
more than 38% decrease between 54 and 165 DAFB. The TA values
obtained in this study are within the range reported by Kulkami and
Aradhya (2005) for ‘Ganesh’ cultivar. High acidity during immature
stage of the fruit could be attributed to the organic acids content
and composition at this stage of fruit development. The decrease in
acidity coincided with increase in pH. The pH of the juice decreased
from early immature (3.57) to early half-ripe stage (3.18), but did
not differ significantly (P>0.05) until the full-ripe stage. As a result
of variations in TSS and TA contents, the ratio of TSS/TA varied considerably
from 54 DAFB (16.68) up to 140 DAFB (39.19), and thereafter
showed no significant increase (P>0.05) till 165 DAFB (41.83). This
suggests that the fruit cultivar may have attained its characteristic
taste and flavor before commercial full-ripe. The ratio of TSS/TA has
been reported as one of the most reliable indicators of fruit maturity
in some pomegranate cultivars although it is largely dependent on cultivar
types (whether the fruit is sweet, sweet-sour or sour), as well as
the agro-climatic conditions (Ben-Arie et al., 1984; Al-Maiman and
Table 1
Moisture content, juice yield, total soluble solids (TSS), titratable acidity (TA), sugar:acid ratio (TSS/TA) and pH from pomegranate juice at different maturity stages.
Chemical component Immature Half-ripe Full-ripe
54 DAFB 82 DAFB 110 DAFB 140 DAFB 165 DAFB
Juice yield (%) 29.31±0.95a 41.95±1.63b 44.68±1.66b 51.03±0.63c 54.93±0.65d
Juice color (Abs. 520 nm) 0.03±0.003a 0.36±0.003a 0.64±0.12a 2.24±0.36b 3.00±0.12b
TSS (°Brix) 10.33±0.35a 11.97±0.19b 13.83±0.29c 15.12±0.25d 16.18±0.21e
TA (% citric) 0.62±0.02b 0.57±0.03b 0.45±0.01a 0.39±0.02a 0.38±0.02a
TSS/TA 16.68±0.35a 21.23±0.58b 30.89±0.59c 39.19±1.31d 41.83±2.21d
pH 3.18±0.03a 3.22±0.05a 3.24±0.23a 3.35±0.04a 3.57±0.13b
Average values (±S.E.) are presented. Different letters on rows mean statistically significant differences (Pb0.05) between the measured parameters at different maturity stages.
The evolution of chemical composition of PJ during fruit developmentalstages is shown in Table 1. Fruit maturity had a significant(Pb0.05) effect on all parameters studied along the days after fullbloom (DAFB). Juice content was 29.31% at 54 DAFB and reached54.93% at full-ripe stage. Previous studies have reported juice contentranging between 25 and 45% during pomegranate fruit developmentalstages of the ‘Wonderful’ pomegranate cultivar (Shulman et al.,1984). There was a steady increase in absorbance as juice colorchanged from white to pink between 54 and 110 DAFB, and then increasedsharply as the color changed from pink to deep red (Fig 1).The overall increase in juice absorbance during fruit developmentalstages is largely as a result of the accumulation of anthocyanins(Shulman et al., 1984).Total soluble solids (TSS) content increased significantly during fruitdevelopment with approximately 1.5-fold increase from 54 DAFB to165 DAFB (Table 1). The TSS found in fully ripened fruits averaging16.2 °Brix was higher than 15.3% reported by Kulkami and Aradhya(2005) for the ‘Ganesh’ cultivar grown in India. According to Ben-Arieet al. (1984), pomegranate fruit of ‘Wonderful’ cultivar grown in Israelattained optimumqualitywhen the TSS of the fruit reached 15%. The increasein TSS could be attributed to the hydrolysis of starch to sugars aspomegranate fruit advancing maturity (Kulkami and Aradhya, 2005).On the contrary, fruit titratable acidity initially decreased sharplyin late immature stage (82 DAFB) then followed by a continuousbut slow decrease with advancing fruit maturity (Table 1). Titratableacidity (TA) ranged from 0.62 to 0.38% (tartaric acid), representingmore than 38% decrease between 54 and 165 DAFB. The TA valuesobtained in this study are within the range reported by Kulkami andAradhya (2005) for ‘Ganesh’ cultivar. High acidity during immaturestage of the fruit could be attributed to the organic acids contentand composition at this stage of fruit development. The decrease inacidity coincided with increase in pH. The pH of the juice decreasedfrom early immature (3.57) to early half-ripe stage (3.18), but didnot differ significantly (P>0.05) until the full-ripe stage. As a resultof variations in TSS and TA contents, the ratio of TSS/TA varied considerablyfrom 54 DAFB (16.68) up to 140 DAFB (39.19), and thereaftershowed no significant increase (P>0.05) till 165 DAFB (41.83). Thissuggests that the fruit cultivar may have attained its characteristictaste and flavor before commercial full-ripe. The ratio of TSS/TA hasbeen reported as one of the most reliable indicators of fruit maturityin some pomegranate cultivars although it is largely dependent on cultivartypes (whether the fruit is sweet, sweet-sour or sour), as well asthe agro-climatic conditions (Ben-Arie et al., 1984; Al-Maiman andTable 1Moisture content, juice yield, total soluble solids (TSS), titratable acidity (TA), sugar:acid ratio (TSS/TA) and pH from pomegranate juice at different maturity stages.Chemical component Immature Half-ripe Full-ripe54 DAFB 82 DAFB 110 DAFB 140 DAFB 165 DAFBJuice yield (%) 29.31±0.95a 41.95±1.63b 44.68±1.66b 51.03±0.63c 54.93±0.65dJuice color (Abs. 520 nm) 0.03±0.003a 0.36±0.003a 0.64±0.12a 2.24±0.36b 3.00±0.12bTSS (°Brix) 10.33±0.35a 11.97±0.19b 13.83±0.29c 15.12±0.25d 16.18±0.21eTA (% citric) 0.62±0.02b 0.57±0.03b 0.45±0.01a 0.39±0.02a 0.38±0.02aTSS/TA 16.68±0.35a 21.23±0.58b 30.89±0.59c 39.19±1.31d 41.83±2.21dpH 3.18±0.03a 3.22±0.05a 3.24±0.23a 3.35±0.04a 3.57±0.13bAverage values (±S.E.) are presented. Different letters on rows mean statistically significant differences (Pb0.05) between the measured parameters at different maturity stages.
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