Flowers, leaves and fruits of hawthorn plant are traditionally used for treating diseases like hypertension and atherosclerosis. The medicinal effects of the plant are generally attributed to its phenolic compounds. However, the fruits are perishable materials because of their high content of water, and generally dried and stored to be used outside its season. The main aim of this research was to investigate the effect of different drying methods on phenolic compounds of the hawthorn fruit. Fruits were collected from the wild growing trees in Turkey. De-seeded fruits were dried in freeze-, oven- (60 oC) and microwave pretreated oven drying (microwave application for 5 min at 360 W before drying at 60 oC) methods and analyzed for antioxidant activity, phenolic compounds, total phenolic content and color parameters. Total phenolic content of fresh hawthorn fruits was found as 13.36 mg g-1 DW. Oven- and microwave pretreated oven drying methods had a reductive effect on total phenolic content and antioxidant activity of fruits when compared to freeze drying method. (-)-Epicatechin (994.10 mg kg-1 DW), rutin (765.30 mg kg-1 DW), and procyanidin B2 (553.80 mg kg-1 DW) were the main phenolics of the fruit. Lowest values of these three compounds were observed in oven-dried fruits. Microwave pretreatment oven drying method resulted in browner product. Although the highest phenolic concentration and antioxidant activity were occurred in freeze-dried sample, microwave pretreatment before oven drying could be applied to reduce the time and cost of drying in terms of phenolic compounds and antioxidant activity.

In this study, the qualities of 15 red pine honey samples from different parts of the Muğla province in Turkey were evaluated. Important chemical parameters such as °Brix, pH, moisture, ash, electrical conductivity, free acidity, proteins, diastase activity, hydroxymethylfurfurale, total reducing sugar, reducing sugar, sucrose, the five common physical parameters refractive index, density, water activity, dynamic viscosity and color index (L*,a* and b*), and mineral compositions, including potassium, sodium, magnesium, phosphorus, calcium, iron, copper, zinc, manganese, nickel, aluminum, boron, molybdenum, and chromium, were determined. Pine honey samples also were analyzed for total phenolic contents and antioxidant activity. The antioxidant activities were evaluated based on the ability of the pine honey extracts to scavenge 1,1-diphenyl-2-picrylhydrazyl. Significant correlations were obtained between the antioxidant activity and phenolic content (r = 0.887). All samples indicated proper maturity, considering the high soluble solids. The values for ash and electrical conductivity were high (0.24–0.60% and 878–1463 μS/cm, respectively). The concentration of 14 minerals of red pine honeys were determined by inductively coupled plasma-atomic emission spectrometry. All samples contained high amounts of potassium, calcium, phosphorus, sodium, iron, magnesium, aluminum, nickel, and zinc. Within the mineral contents, potassium was quantitatively the most important mineral, having an average content of 3,802 ppm, and accounted for 45% the minerals.

The aim of this study was to determine whether a change occurs in the phenolic compounds and antioxidant activity of grapes after drying. Grapes pre-treated with potassium hydroxide solution were dried using three different drying methods, namely freeze drying, oven drying and sun drying. The effectiveness of the drying methods was evaluated in terms of total phenolic content, antioxidant activity (ABTS, FRAP and DPPH), individual phenolics and anthocyanins. Losses in total phenolic content of the grapes were found to be 1.89, 20.26 and 46.79% for freeze-, oven- and sun-dried grapes respectively. The DPPH and ABTS antioxidant activities of the grapes decreased after drying by all three methods, while an increase was observed in the FRAP value of freeze-dried grapes compared to the fresh sample. No significant effect of drying methods was observed on the gallic acid, 2,5-dihydroxybenzoic acid and (-)-epigallocatechin gallate contents of the grapes. The highest levels of procyanidin B1, (+)-catechin, (-)-epicatechin, (-)-epicatechin gallate, chlorogenic acid, trans-resveratrol and rutin were determined in freeze-dried grapes. Sun and oven drying caused drastic decreases in all anthocyanins, while no loss of anthocyanin was observed in freeze-dried grapes. Sun drying was found to be the most detrimental drying method for grapes in terms of phenolic compounds and antioxidant activity when compared to the other drying methods.