No abstract

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.

The barberry (Berberis vulgaris L.) fruits growing wild in Turkey were analyzed for some physical (dimensions, geometric mean diameter, sphericity, bulk density, fruit density, volume, terminal velocity, hardness and porosity) and chemical (moisture, reducing sugar, ascorbic acid, total anthocyanin and phenolics, crude protein, crude oil, crude energy, crude fiber, ash, pH, acidity, alcohol‐soluble extract and color) properties. Mineral content of barberry fruits growing wild in Turkey was determined by inductively coupled plasma‐atomic emission spectrometry. The average pulp mass ratio, thickness, width, length, mass, volume, geometric mean diameter, sphericity and projected area were measured as 75.59%, 3.51 mm, 3.32 mm, 7.69 mm, 0.07 g, 71 mm3, 4.46 mm, and 0.58 and 0.2535 cm2, respectively. The energy, reducing sugar, protein, cellulose, oil, ash, acidity, ascorbic acid, total phenolics, total anthocyanin and soluble solid matter values of barberry fruits were established as 69.25 kcal/g, 6.52%, 10.32%, 9.42%, 0.84%, 1.12%, 3.10%, 256.48 mg/kg, 789.32 mg/100 g, 931.05 mg/kg and 19.4%, respectively. It is very important to evaluate the technological properties of equipment used in harvesting, transportation, storage and processing of fresh fruits. Also, the information supplied on the proximate composition of the barberry fruit is highly beneficial for human nutrition. PRACTICAL APPLICATIONS The chemical properties such as ascorbic acid, anthocyanin and phenolic compounds, reducing sugar, crude protein, crude fiber, crude oil, ash and mineral contents of barberry fruits are mostly important for human nutrition and processing. In addition, it is very important to establish the physical properties of equipment used in harvesting, transportation, storage and processing of fresh fruits. However, further studies are necessary to understand the physical properties for equipment design and to provide necessary information for the use of wild edible fruits.

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 as the most detrimental drying method for grapes in terms of phenolic compounds and antioxidant activity when compared to the other drying methods.

In this study, proximate composition, certain quality and rheological properties of sesame pastes (tahin) produced from hulled roasted sesame seeds (without hull), called simply tahin, from unhulled roasted sesame seeds (with hull), so‐called Bozkir tahin, and their blends (25–75%) were determined at temperatures ranging from 15 to 65C and shear rates from 0.5 to 100 1/s. Tahin, Bozkir tahin and their blends were found to exhibit non‐Newtonian, pseudoplastic behavior at all temperatures. Apparent viscosity versus shear rate data were successfully fitted to the power law model. The flow behavior index, n, varied in the range of 0.4587–0.6830. The consistency coefficient, K, was in the range of 3.97–28.08 Pa·sn. Both parameters were significantly affected by temperature. The increase in levels of unhulled sesame seeds in tahin resulted in higher viscosity (K) for all temperatures. Temperature sensitivity of the consistency coefficient was assessed by applying an Arrhenius‐type equation, and Ea value appeared in the range of 17.87–24.92 kJ/mol. PRACTICAL APPLICATIONS Roasting of sesame seeds is the most significant step in tahin processing that causes important physical, chemical, structural and sensorial changes. The sesame roasting is carried out to promote more flavor, desired color and texture changes that ultimately increases the overall palatability. A major concern facing the tahin industry is the production of a product with proper consistency, emulsion stability, color and textural properties. Reliable and accurate rheological data are necessary for the design of flow process and to evaluate heating and cooling rate during different engineering operations. So, this work is very important in terms of the estimation of physicochemical and rheological properties of sesame paste containing hulls.