Effect of a guava and passion fruit juice on diabetic patients with hypertension

Methods

Summary

Antioxidant activity: Antioxidant activity will be analyzed by the DPPH, FRAP and ORAC methods. I) DPPH method: the method is based on the reaction of sample with 10 mL of 990 mL of DPPH solution for 30 min at room temperature. Results are expressed in Trolox equivalent antioxidant capacity (TEAC) (Zapata et al 2013). Ii) Assay FRAP: This method is based on the increase in absorbance due to formation of 2, 4, 6-tripyridil-s-triazine (TPTZ) -Fe (II) in the presence of reducing agents. Values are expressed as FRAP EACA (ascorbic acid equivalent antioxidant capacity: mg ascorbic acid per L, using a standard curve of ascorbic acid (Zapata et al 2013) iii.) ORAC: 3 mL contains 21 .mu.L of mixture 10 m M fluorescein solution, 2899 ul of 75 mM phosphate buffer (pH 7.4), 50 .mu.l of 600 mM of 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH) and 30 .mu.l of juice. The ORAC value is reported as Trolox pmol / L (Zapata et al, 2013).

 Proximate analysis: Standard protocols stipulated by (ICONTEC) and the Association of Official Analytical Chemists (AOAC) methods per 100 mL of beverage will be held.

 Analysis of secondary metabolites: I) Total phenols are determined according to the Folin-Ciocalteu adapted method. Results are expressed as Gallic acid equivalents (GAE) / L (Zapata et al, 2013); ii) Total flavonoids: by the colorimetric method described by Marinova, et al, 2005. (+) is determined - Catechin standard solution used for calibration curves and results are expressed as catechin equivalents / L; iii) total carotenoids: the method used for extraction is acetone and measured absorbance is measured at 449 nm to. The β-carotene standard solution used for calibration curves and results are expressed as β-carotene mg / L (Zapata et al 2013).

  Microbiological analysis: according to NTC 4458 1998 (aerobic mesophilic bacteria, fungi, yeasts, total and fecal coliforms); and according to NTC 4574 (Salmonella sp).

 Sensory analyses: The affective method will be used by test method pleasantness using the 3-point hedonic scale: I like it, nor do I like or dislike, and disgusts me to color, smell, taste, sweetness and consistency; and an acceptance test. The product will be evaluated by trained panelists of both genders.

Challenges

Compliance to the dietary intervention is the biggest challenge. It is estimated that the intake of fruits and vegetables is low worldwide and is linked to approximately 31% of cases of ischemic heart disease and 11% of strokes (Ministry of Health in Colombia). The total mortality rate worldwide attributed to low consumption of fruits and vegetables currently stands at 2,635 million deaths per year.

In order to ensure compliance the participants will be asked to provide an additional blood sample on a random day of the second week of each intervention. This will be done in order to assess compliance with the instructions. All participants and their serum samples will be coded by number, and the tests will be carried out blinded. Subjects will be instructed to consume 500 mL of guava passion fruit juice or placebo daily as follows: 250 mL and 250 mL fasting before dinner. Compliance with the lowest participants 80% will serve as a reason to be withdrawn from the study

Pre Analysis Plan

Obtaining blood samples and analysis: Blood samples will be collected after an overnight fast and will be stored at - 20 ° until analysis. The serum concentration of IL-1β, TNF-α, IL-6 and C-reactive protein will be measured using commercial kits and following the manufacturer instruction. The concentration of glucose, lipid profiles will be determined by a certified clinical laboratory. Analyses of total antioxidant capacity and thiobarbituric acid reactive substances (TBARS) will be measured using the respective commercial kits. Lycopene levels in serum and juice will be analyzed by HPLC by comparison with the retention time of a standard and quantified by comparison with the peak area in a standard curve.

Dietary analyses: Records of a 3 day diet will be analyzed by the software program EVINDI (Evaluation of the dietary intake). This software is a computer program developed by the School of Nutrition and Dietetics at the University of Antioquia. The results are presented as the mean of 3 days for each nutrient during the specific period.

Statistical analyses: Data are expressed as average ± standard error of the mean. The Kolmogorov-Smirnov test was used to confirm that the data is normally distributed. The significance of differences between samples before and after supplementation will be analyzed by a paired t-test. P values <0.05 were considered statistically significant. A general linear model repeated measures analysis will be conducted to determine if there are interactions between treatment and phases. The Pearson correlation coefficients were used to examine associations between variables change