In the step for precipitating PA in supernatant S3, only 1.5 M Na2CO3 was used, as described in the previous step for adjusting the pH from 7.0 to 9.0 at 0.5 pH value intervals. After filtering with filter paper Whatman # 3 and drying the pellet in an oven at 60 °C, a white powdery PA was obtained. The yield of purified PA (Table 5) at different pH values did not differ among groups (p > 0.05). The addition of 1.5 M Na2CO3 decreased the purity grade because larger volumes of 1.5 M Na2CO3 were used for the precipitation. The maximum degree of purity was obtained when the S3 pH was adjusted to 7.0 or 7.5; these two values did not differ significantly (p > 0.05). In this purification step, the supernatant S3 pH was adjusted to 7.0 using 1.5 M Na2CO3 because of the possibility of lowering the number of impurities (21.81 ± 0.86%) present in the purified PA. The loss of PA during the analytical purification process was evaluated after identifying the pH adjustments of supernatants S2 and S3 with 1.5 M Na2CO3 with the determination of PA in pellets P1 and P3 and supernatant S2 and supernatant S4 ( Fig. 1). The total loss of 1.42 ± 0.03 g PA in 100 g of rice bran represented a 26.88 ± 0.52% loss of PA, considering the content of an initial sample of 5.37 ± 0.09 g of PA in 100 g of rice bran. Therefore, it was confirmed that the technique of extraction and purification of PA was possible with a recovery of 72.88 ± 0.98 g 100 g−1 of rice bran, a purity of 78.19 ± 0.86% and a yield of 73.21 ± 0.90% ( Table 5).
In the step for precipitating PA in supernatant S3, only 1.5 M Na2CO3 was used, as described in the previous step for adjusting the pH from 7.0 to 9.0 at 0.5 pH value intervals. After filtering with filter paper Whatman # 3 and drying the pellet in an oven at 60 °C, a white powdery PA was obtained. The yield of purified PA (Table 5) at different pH values did not differ among groups (p > 0.05). The addition of 1.5 M Na2CO3 decreased the purity grade because larger volumes of 1.5 M Na2CO3 were used for the precipitation. The maximum degree of purity was obtained when the S3 pH was adjusted to 7.0 or 7.5; these two values did not differ significantly (p > 0.05). In this purification step, the supernatant S3 pH was adjusted to 7.0 using 1.5 M Na2CO3 because of the possibility of lowering the number of impurities (21.81 ± 0.86%) present in the purified PA. The loss of PA during the analytical purification process was evaluated after identifying the pH adjustments of supernatants S2 and S3 with 1.5 M Na2CO3 with the determination of PA in pellets P1 and P3 and supernatant S2 and supernatant S4 ( Fig. 1). The total loss of 1.42 ± 0.03 g PA in 100 g of rice bran represented a 26.88 ± 0.52% loss of PA, considering the content of an initial sample of 5.37 ± 0.09 g of PA in 100 g of rice bran. Therefore, it was confirmed that the technique of extraction and purification of PA was possible with a recovery of 72.88 ± 0.98 g 100 g−1 of rice bran, a purity of 78.19 ± 0.86% and a yield of 73.21 ± 0.90% ( Table 5).
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