Nutritional Analysis of Red-Purple and White-Fleshed Pitaya (Hylocereus) Species.

Pitaya is one of the most preferred and produced tropical fruit species recently introduced to the Mediterrranean region in Turkey. Due to its nutritional fruits with high economic value, the popularity of pitaya increases steadily in Turkey as an alternative crop. No detailed nutritional analysis has been undertaken in Turkey so far on fruits of the pitaya species. In this study, we determined and compared some nutritional parameters in fruit flesh of two pitaya (dragon fruit) species (Hylocereus polyrhizus: Siyam and Hylocereus undatus: Vietnam Jaina) grown in the Adana province located in the eastern Mediterranean region in Turkey. The individual sugars, antioxidant activity, total phenolic content, phenolic compounds and volatiles were determined for the first time in Turkey on two pitaya species. The results showed that total phenol content and antioxidant capacity are notably higher in red-fleshed fruits than white-fleshed ones and the predominant phenolic compound in fruits of both species was quercetin. The total sugar content and most of the phenolic compounds in fruits of two pitaya species were similar. A total of 51 volatile compounds were detected by using two Solid Phase Micro Extraction (SPME) fibers, coupled with Gas Chromatography Mass Spectrometry (GC-MS) techniques, and more volatile compounds were presented in the white-fleshed species. Total phenolic content (TPC) of the red-fleshed and white-fleshed pitaya species were 16.66 and 17.11 mg GAE/100 g FW (fresh weight). This study provides a first look at the biochemical comparison of red-fleshed and white-fleshed pitaya species introduced and cultivated in Turkey. The results also showed, for the first time, the biochemical content and the potential health benefit of Hylocereus grown in different agroecological conditions, providing important information for pitaya researchers and application perspective.

Comparison of Polyphenol, Sugar, Organic Acid, Volatile Compounds, and Antioxidant Capacity of Commercially Grown Strawberry Cultivars in Turkey.

The aim of this study was to compare certain important fruit quality parameters such as sugars, organic acids, total phenolic content, antioxidant capacity, and volatile compounds of 10 commercial strawberry cultivars grown in the research and experimental area in Yaltir Agricultural Company located in Adana provinces of Turkey. As for the sugar content of strawberry fruits, fructose was identified as the dominant sugar and the highest value (4.43%) was found in the cultivar "Rubygem". In terms of organic acid, among the examined strawberry cultivars, "Calinda" had the greatest level of citric acid (711.45 mg g-1). Regarding vitamin C content, the highest amount was found in the cultivar "Sabrina" (25.08 mg 100 g-1). Ellagic acid was the main phenolic acid in all examined cultivars (except the "Plared" cultivar), and the highest amount was detected in the "Fortuna" cultivar (3.18 mg 100 g-1). We found that the cultivar FL-127 had the highest total phenolic content (158.37 mg gallic acid equivalent 100 g-1 fresh weight base). Regarding antioxidant capacities, the highest value (88.92%) was found in the cultivar Victory among all the cultivars studied. The detailed analysis of volatile compounds was performed by gas chromatography/mass spectrometry (GC/MS) and 34 compounds were detected. Among them, esters, acids, and alcohols were found to be the major volatile compounds in strawberry fruits. In conclusion, strawberry fruits belong to ten cultivars showed abundant phenolic compounds and at the same time have high antioxidant activity.