Abstract
Introduction: Fruit juices have been increasing interest due to their antioxidant properties. These antioxidants could act beneficially in the health maintenance by preventing free radicals formation [Citation1]. However, processing and temperature, can modify its antioxidant properties [Citation2]. It is, therefore, relevant to know their antioxidant properties and compare them with their manufactured equivalents.
Materials and methods: Ten independent samples of commercial juice (CJ) and ten samples of equivalent manufactured juice (MJ) were analyzed. DPPH and FRAP methods were performed to evaluate antioxidant activity (AA) and Folin-Ciocalteau test evaluated the total phenol content (TPC). The t-Student test was applied to compare the TPC of the two juices, the two-way ANOVA was used to compare the AA of the two juices for the two tests and the Spearman coefficient to verify the correlation between TPC and AA.
Results: Regarding de comparison of the juices for TPC, the results revealed a significant difference between juices. A strong interaction between the two factors, juice and method was found, which influences the AA. The AA results revealed no significant difference between methods for CJ in spite of a difference for MJ (). The Spearman Correlation Coefficient obtained for the association between TPC and AA for FRAP and DPPH tests revealed a strong correlation (R = 0.883 and R = 0.550, respectively) with statistical significance (p < 0.01), for MJ. Concerning CJ, a weak correlation was found between TPC and AA in both methods (R = 0.467 and R = 0.018, respectively), without statistical significance (p > 0.1).
Discussion and conclusions: The present study revealed similar values with literature [Citation3,Citation4] that, for the studied juices, the antioxidant properties of CJ are higher than MJ. The results may be related to the presence of ascorbic acid in CJ, added to act as a preservative [Citation4].
Table 1. Total Phenol Content (TPC) and antioxidant activity (AA) results for the commercial juice (CJ) and the equivalent manufactured juice (MJ). Samples were analyzed in triplicate. Data are presented as mean value ± SEM.
Acknowledgements
The authors are thankful to Go Natural, for the commercial juices and recipe supplying.
References
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