Influence of conventional and organic agriculture practices on the total phenols and antioxidant potential of Florina apple fruits

Abstract

The aim of the current study was to evaluate the influence of conventional and organic growing conditions on the total phenolic content, the total flavonoids content, the total monomeric anthocyanins content and the antioxidant potential in the apple fruits of Florina variety. The samples were grown and collected from the experimental fields, around Plovdiv and the village of Brestnik. The total phenolic content, the total flavonoids, the total monomeric anthocyanins content were determined. The antioxidant potential was evaluated by four different assays. The apple fruits grown under organic conditions contained higher total phenolics and they showed stronger antioxidant activity than fruits from the conventional conditions. The total phenolic content was from 3 to 5 mg gallic acid equivalent/g dry weight. The total flavonoids were below 1 mg quercetin equivalents/g dw. In the organically grown fruits, the average values for antioxidant activity varied from 30 to 100 mM Trolox® equivalent/g dw. The total monomeric anthocyanins in the organically grown apples their levels were the highest (67 mg cyn-3-glc/100 g dw). There was a positive, high correlation between antioxidant methods and the total phenolic content and total monomeric anthocyanins. These results indicated that organically grown apples accumulated higher levels of antioxidants and bioactive compounds, in comparison to conventionally grown apples.

Physicochemical Properties of Apple Purees and Peel Extract for Potential Use in Pastry Products

“…Moisture content determination was performed according to AOAC Official Method 934.06. This procedure involves drying 5 g of sample at 103 ± 2 • C until a constant mass is obtained [28,[42][43][44][45]. Three determinations were performed for each sample.…”

“…The ash content was determined by calcining the sample at 550-600 • C in the calcination furnace until a constant mass was obtained [28,[42][43][44][45].…”

“…After one hour, the extract was filtered, and 0.2 mL of the extract was introduced into a volumetric flask, over which 1.8 mL of deionized water, Folin-Ciocalteu reagents (10 mL of 1:10 reagent) and sodium carbonate were added (8 mL of 7.5% concentration). The color formation time was 2 h. The analyses were performed in triplicate for each product, at λ = 765 nm, using the Shimadzu 300 UV-VIS-NIR spectrophotometer (Tokyo, Japan), and the results were expressed in mg gallic acid equivalent (GAE)/kg fresh mass (FM), using its calibration curve [28,30,43].…”

“…The apple (Malus domestica) is a widely consumed fruit throughout the world, being one of the most cultivated fruit species and being in the top five most consumed fruits [26,27]. They are preferred by consumers due to their flavor and high nutritional value, being rich in vitamins, minerals and phenolic compounds [28][29][30]. Properly stored, these can be available throughout the year both in its biological form and in the form of juices, purees, cider, frozen or dried slices [28,31,32].…”

“…They are preferred by consumers due to their flavor and high nutritional value, being rich in vitamins, minerals and phenolic compounds [28][29][30]. Properly stored, these can be available throughout the year both in its biological form and in the form of juices, purees, cider, frozen or dried slices [28,31,32]. The processing of apples implies the loss of 25% of their mass; thus, parts such as pulp, peel and seeds are thrown away [31,33].…”