Preservation of the Polyphenolic Content and Antioxidant Properties of Rubus Glaucus Benth

Abstract

The Andes berry (Rubus glaucus Benth) has an ongoing production in Colombia and is considered a competitive market product with the potential for exportation and broad applications in agroindustry because of its high content of antioxidants, nutrients, and proteins, which are keys to a balanced diet. In this study, the effect of an Aloe vera gel coating on the preservation of the nutraceutical properties of the Andes berry was evaluated by measuring the antioxidant capacity and the total phenolic content of the fruit using the DPPH (2, 2-diphenyl-1-picrylhydrazyl) and Folin-Ciocalteu methods, respectively. The antioxidant activities in fruits without and with coating were 95.14 ± 3.28 mmol AAE 100 g-1 sample and 135.94 ± 1.09 mmol AAE 100 g-1 sample, respectively, after ten day of storage. The total phenolic content of the fruits with and without coating did not present significant differences, i.e., the phenol concentrations remained constant over time. Implementation of the gel coating is recommended as a low-cost and highly available option for the preservation of the Andes berry and its nutraceutical properties.

Aloe Vera Gel Edible Coating for Shelf Life and Antioxidant Proprieties Preservation of Andean Blackberry

“…By having low water solubility and a higher permeability, it will be less likely that the coating will be susceptible to deterioration during fruit storage. The results obtained in this study demonstrated the ability of the Aloe vera coating to extend the shelf life of Andean blackberry fruit, similar results were obtained by [23] who evaluated the preservation of the polyphenolic content and antioxidant properties of Rubus glaucus Benth.…”

“…According to the study carried out by Velasquez-Castro, et al, (2019) [23], the total phenols content did not show differences between coated and uncoated fruits (p > 0.05), while during storage the differences became statistically significant, a similar behavior found in this study. On the first day, the total phenol content was 316.94 ± 2.75 mg GAE L −1 sample and 329.44 ± 6.285 mg GAE L −1 sample and increased significantly to 450 ± 3.93 mg GAE L −1 sample and 470 ± 3.93 mg GAE L −1 sample after storage 19 days for the coated and uncoated fruits, respectively.…”

“…According to the antioxidant activity by the DPPH method (Figure 5), the coated and uncoated fruits present significant differences, as well as the days evaluated (p < 0.05), where the coated fruits have higher antioxidant activity, similar results found for blackberry (Rubus glaucus Benth) for ten days [23], raspberry (Rubus spp) for eight days [36], raspberry (Rubus ulmifolius subsp sanctus) for nine days [37], and strawberry (Fragaria ananassa cv Hongyan) for six days [38].…”

“…The coating developed based on Aloe vera and starch for the fruits of Andean blackberry showed low solubility, high permeability, a high elongation percentage, and a high TS, enabling a delay in fruit transpiration and decreasing the weight loss during storage, which also increased the shelf life of the blackberries by 15 days compared to the control and by 19 days compared to that reported by [39]. These authors managed to conserve blackberries for up to 10 days using coatings based on Aloe vera, carnauba wax, and glycerol [23,39]…”

“…Each Andean blackberry was submerged in the selected coating according to the best physical, barrier, and mechanical properties. The berries rested in a sieve for 10 min to remove the excess coating and were then dried for two hours with cold air (27 • C) [23].…”