*2.9.3 Total acidity*

A 2.5 mL sample of pitanga juice was previously homogenized and filtered in 100 mL Erlenmeyer flasks, afterwards it was diluted in 25 mL of distilled water and then stirred. Soon after, the electrode was introduced into the solution and then it was titrated with Sodium hydroxide solution (0.1 N) until the pH remained between 8.2 and 8.4 [34]. The potentiometer was previously calibrated before the analysis with pH 4 and 7 buffer solutions.

#### **2.10 Total phenolics**

The total phenolic content was estimated according to the Folin–Ciocalteu method [35].

#### **2.11 Antioxidant activity**

The antioxidant activity was assessed through the DPPH (2, 2-diphenyl-1 picrylhydrazyl) method [36].

The DPPH *radical scavenging* activity was calculated according to the equation (Eq.(2)) below:

$$\text{DPPH} \left( \% \right) = \left[ \left( \mathbf{A}\_o - \mathbf{A}\_1 / \mathbf{A}\_o \right) \right] \cdot \mathbf{100}.\tag{2}$$

Where A0 corresponded to the absorbance of the negative control, and A1 to the absorbance in the presence of the compound (sample and Trolox). Trolox was the positive control.

*Biotransformation of Pitanga Juice by Tannase from* Saccharomyces cerevisiae *CCMB 520 DOI: http://dx.doi.org/10.5772/intechopen.96103*

### **2.12 Statistical analysis**

Each 10 mL of pitanga juice in Erlenmeyer flasks was added partially purified tannase at the proportions cited in **Table 1** and incubated in a shaker at 120 � 1 rpm at 30 °C, optimal temperature of the tannase from *Saccharomyces cerevisiae* CCMB

The physical–chemical evaluation is necessary since bioconversion cannot influence the loss of quality with respect to the pre-established minimum standards for the Standard of Identity and Quality of a specific product, in this case the integral

The pH was determined directly in the same with the aid of a previously

Total Soluble Solids (°Brix) was determined by a Reichert digital refractometer by dropping two drops of the sample onto the surface of the properly calibrated

A 2.5 mL sample of pitanga juice was previously homogenized and filtered in 100 mL Erlenmeyer flasks, afterwards it was diluted in 25 mL of distilled water and then stirred. Soon after, the electrode was introduced into the solution and then it was titrated with Sodium hydroxide solution (0.1 N) until the pH remained between 8.2 and 8.4 [34]. The potentiometer was previously calibrated before the

The total phenolic content was estimated according to the Folin–Ciocalteu

The antioxidant activity was assessed through the DPPH (2, 2-diphenyl-1-

The DPPH *radical scavenging* activity was calculated according to the equation

Where A0 corresponded to the absorbance of the negative control, and A1 to the absorbance in the presence of the compound (sample and Trolox). Trolox was the

DPPH %ð Þ¼ ½ð Þ *Ao* � *A*1*=*A*<sup>o</sup>* � � 100*:* (2)

520 [33]. After the enzymatic application was done, according to the preestablished time, the enzyme was denatured at 70 °C, for 10 minutes.

**2.9 Physico-chemical analysis of the pitanga juice**

calibrated pHmeter, after filtration [34].

analysis with pH 4 and 7 buffer solutions.

*2.9.2 Total soluble solids (°Brix)*

pitanga juice.

*Saccharomyces*

*2.9.1 pH*

apparatus.

*2.9.3 Total acidity*

**2.10 Total phenolics**

**2.11 Antioxidant activity**

picrylhydrazyl) method [36].

method [35].

(Eq.(2)) below:

positive control.

**22**

The results were analyzed in the SISVAR software - Variance Analysis System [37] and the means were compared through the Scott-Knott test at 5% probability level. In addition, the results were assessed through Analysis of Variance (ANOVA) in the Statistica Version 10.0 software (StatSoft, Inc., Tulsa, USA) [38] to find the variables presenting statistically significant effects on enzyme application (p < 0.05), as well as the model fitting the experimental data. All assays were performed in random order.
