Mohammad N. Alhamad

Effect of jam processing and storage on total phenolics, antioxidant activity, and anthocyanins of different fruits.

BACKGROUND Fruits have been widely recognised as an excellent source of bioactive phenolic compounds. The purpose of this study was to evaluate the effect of jam processing of strawberry, cherry, apricot, fig and orange on the total phenolics, antioxidant activity and anthocyanins during 5 months of storage at 25 °C. RESULTS Fresh strawberry had the highest contents of total phenolics (8503.1 mg GAE kg(-1) ) followed by cherry, apricot, fig and orange, respectively. Jam processing decreased the total phenolics, antioxidant activity, and anthocyanins of all fruits. Total phenolics of jam during storage decreased only in apricot, fig and orange. Fresh strawberry had the highest antioxidant activity (54.88% inhibition) followed by the other fruits. Antioxidant activity did not change in strawberry during jam storage, while there are reductions in the other fruits were observed. Fresh strawberry had the highest anthocyanins (2323.8 mg cya-3-glu kg(-1) ), followed by cherry and the other fruits, respectively. Results showed only a decrease of anthocyanins and pH in apricot and fig jams during 5 months of storage. CONCLUSION Despite the reduction of these compounds in jam processing, it is considered a good method to maintain them during 5 months of storage.

Land use/cover classification of arid and semi‐arid Mediterranean landscapes using Landsat ETM

Land use/cover classification in heterogeneous east Mediterranean landscapes is challenging, e.g. Jordan. Digital land use/cover maps are needed at an appropriate cost, spatial and temporal coverage. North‐western Jordan is appropriate for exploring the use of Landsat ETM imagery in land use/cover delineations as its biogeographic zones are very diverse and heterogeneous. Supervised and unsupervised classification schemes were used with and without spatial enhancement techniques. Sources of classification errors were inspected statistically. Results indicated that Landsat ETM images are effective in classifying heterogeneous Mediterranean landscapes with an accuracy of up to 83%. Accuracy was enhanced by approximately 9% using supervised classification. Spatial enhancement improved accuracy of certain classes and reduced it for others. Results call for class‐specific classification schemes. Areas of the different land use/cover classes of the study area were estimated from the classified image. Urban, shrubland and rangeland areas were estimated for the first time. There is a growing concern about the governmental census estimates of certain classes.

Effects of Green Tea and Grape Seed and TBHQ on Physicochemical Properties of Baladi Goat Meats

The effect of natural extracts of green tea or commercial grape seed in combination with synthetic tert methyl-butylhydroquinone at different concentrations on lipid oxidation and the redness of goat meats stored at 5°C for 9 days was evaluated. Fresh boneless Baladi goat meats were ground and mixed at varying concentrations of green tea or grape seed extract alone or combined with tert methyl-butylhydroquinone. The color values of raw goat meat and the thiobarbituric acid-reactive substance values of raw and cooked goat meats were determined following 0, 3, 6, and 9 days of storage at 5°C. The antioxidant activity of the plant extracts and the tert methyl-butylhydroquinone ranged from 4.6–10.2 h induction time using an oxidative stability instrument. Thiobarbituric acid-reactive substance values ranged from 0.21 to 1.21 and 0.31 to 4.57 mg malondialdehyde/kg (goat meat) for the raw and cooked goat meats, respectively. Tert methyl-butylhydroquinone and plant extracts significantly decreased lipid oxidation of the goat meats, with a higher level of addition being more effective in minimizing lipid oxidation. Grape seed extract significantly increased the redness, while green tea extract decreased it; no effect of tert methyl-butylhydroquinone on the redness of goat meats was observed. This study has shown that inclusion of natural extracts of green tea and grape seed in goat meat could reduce lipid oxidation during its storage.

A review of phenolic compounds in oil-bearing plants: Distribution, identification and occurrence of phenolic compounds.

Over the last two decades, separation, identification and measurement of the total and individual content of phenolic compounds has been widely investigated. Recently, the presence of a wide range of phenolic compounds in oil-bearing plants has been shown to contribute to their therapeutic properties, including anti-cancer, anti-viral, anti-oxidant, hypoglycemic, hypo-lipidemic, and anti-inflammatory activities. Phenolics in oil-bearing plants are now recognized as important minor food components due to several organoleptic and health properties, and they are used as food or sources of food ingredients. Variations in the content of phenolics in oil-bearing plants have largely been attributed to several factors, including the cultivation, time of harvest and soil types. A number of authors have suggested that the presence phenolics in extracted proteins, carbohydrates and oils may contribute to objectionable off flavors The objective of this study was to review the distribution, identification and occurrence of free and bound phenolic compounds in oil-bearing plants.

Optimisation and characterisation of various extraction conditions of phenolic compounds and antioxidant activity in olive seeds

This study was conducted to optimise the extraction conditions of phenolic compounds to evaluate antioxidant extraction parameters and to identify the major free and bound phenolic compounds in olive seeds. The results obtained using methanol as an extraction solvent for olive seeds indicated that the optimised total phenolic content and antioxidant activity were obtained at an extraction time of 12 h, an extraction temperature of 70°C and an extraction cycle of three stages. The correlation coefficient between total phenolic compounds and antioxidant activities was positive (R 2 = 0.83). The major finding is that the predominant phenolic compounds in olive seeds were present in free form. However, a small percentage of the bound phenolic compounds was found in olive seeds compared to that of the free phenolic compounds. This study recommends that olive seeds with optimised extraction conditions (i.e. optimised correlation between phenolic compound contents and antioxidant activities) can be used as potential food additive candidates in functional, nutraceutical and pharmaceutical industries.

Investigation of Natural Lipid–Phenolic Interactions on Biological Properties of Virgin Olive Oil

There is limited knowledge regarding the impact of naturally occurring lipid-phenolic interactions on the biological properties of phenolics in virgin olive oil. Free and bound phenolics were isolated via sequential methanolic extraction at 30 and 60 °C, and were identified and quantified using reversed phase high performance liquid chromatography, liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), and gas chromatography. Decreased oleic acid concentrations and increased concentrations of palmitoleic acid, stearic, linoleic, and linolenic acids were observed in virgin olive oil after removal of free and bound lipid phenolic compounds. The presence of p-hydroxybenzoic acid and tyrosol bound to glycerides was determined via LC-MS/MS, which indicates natural lipid-phenolic interactions in virgin olive oil. Both free and lipid bound phenolic extracts exerted antiproliferative activities against the CRC1 and CRC5 colorectal cancer cell lines. The present work indicates that naturally occurring lipid-phenolic interactions can affect the biological properties of phenolics in virgin olive oil.

Estimating east Mediterranean forest parameters using Landsat ETM

The conservation of Jordans Mediterranean forest requires the use of remote sensing. Among the most important parameters needed are the crown-cover percentage (C) and above-ground biomass (A). This study aims to: (1) identify the best predictor(s) of C using Landsat Enhanced Thematic Mapper (ETM) bands and the derived transformed normalized difference vegetation index (TNDVI); (2) determine if C is a good predictor of A, volume (V), Shannon diversity index (S) and basal area (B); and (3) generate maps of all these parameters. A Landsat ETM image, aerial photographs and ground surveys are used to model C using multiple regression. C is then modelled to A, V, S and B using linear regression. The relationship between C and Landsat ETM bands (1 and 7) plus the TNDVI is significantly high (coefficient of determination R 2 = 0.8) and is used to produce the C map. The generated C map is used to predict A (R 2 = 0.56), V (R 2 = 0.58), S (R 2 = 0.50) and B (R 2 = 0.43). Cross validation for the predicted C map (cross-validation error = 5.3%) and for the predicted forest-parameter maps (cross-validation error = 13.7%–19.9%) shows acceptable error levels. Results indicate that Jordans east Mediterranean forest parameters can be mapped and monitored for biomass accumulation and carbon dioxide (CO2) flux using Landsat ETM images.

Optimization of Phenolic Content, Antioxidant, and Inhibitory Activities of α-Glucosidase and Angiotensin Converting (AC) Enzymes from Zingiber officinale Z.

The optimum extraction conditions of phenolic compounds from ginger were evaluated with respect to antioxidant activity and angiotensin converting enzyme and α-glucosidase inhibitory activities. Free phenolics were extracted under conditions that varied according to extraction time, temperature, and solvent type (water, acetone, and methanol). Acid and base hydrolysis reactions were used to obtain bound phenolic compounds from ginger. The results showed that the type of solvent used and the temperature and time of extraction needed for maximal total phenolic content, antioxidant activity, and angiotensin converting enzyme inhibitory activity differed greatly from solvent conditions and showed the greatest α-glucosidase inhibitory activity. The predominant free phenolics in the methanol extracts included diosmin, thymol, and carvacrol, which varied greatly according to solvent extraction conditions (i.e., time and temperature). Diosmin was the predominant bound phenolic compound of the methanol extracts. The present study findings indicate that differing solvent extraction protocols involving extraction time and temperature for ginger need to be explored to generate specific optimal bioactivities of the extracts, which are related to the pattern of predominant phenolics in those extracts.

Genetic diversity of the easternmost fragmented mediterranean Pinus halepensis Mill. populations

The genetic structure of fragmented Aleppo pine (Pinus halepensis Mill.) populations in Jordan was investigated using RAPD markers. The level of within-population polymorphism was low, while differentiation among populations was large, suggesting a low level of gene flow. Population differentiation and genetic distance between populations were not related to geographical distance. Clustering based on multivariate discriminant analysis showed that geographically distant populations clustered together with a high clustering accuracy and strong relationship to rainfall. Results supported that the current population configuration is the result of fragmentation of a once larger and contiguous population due to Holocene conditions exacerbated by increased human disturbance of forest ecosystems. Implications for conservation strategies are discussed.

Environmental gradients and community attributes underlying biodiversity patterns of semi-arid Mediterranean grasslands

Protection and/or establishment of forest plantation have been used as a management strategy to conserve and stop the deterioration of semi-arid Mediterranean grasslands ecosystems, producing a mosaic of vegetation types. This study was intended to investigate the changes in grassland community in response to protection and forest tree plantation practice as well as to explore the underlying environmental gradients responsible for the observed differences or similarities among these vegetation types. Two multivariate analysis methods including discriminate analysis and non-metric multi-dimensional scaling were used to quantify changes in community composition and attributes following different management practices (free grazing, protection with open grassland, sparse and dense forest tree plantations). This was investigated using species frequency, species abundance, or habitat characteristics. The study results showed that habitat types differed significantly between each other and were significantly separated using multivariate approaches. Discrimination based on habitat characteristics and species composition indicated that protection (or grazing) and light (or shade) explained more than 90% of the observed variability in community changes in response to the protection and forest tree plantation. Also, results indicated that shade effect can be attributed to tree canopy cover and/or litter accumulation on the ground. It could be hypothesized that protection from grazing and afforestation resulted in complex environmental gradients of which shade, litter accumulation as well as protection from grazing disturbance are major constituents. A careful manipulation of protection and afforestation can be used to create a spatially different environmental gradients leading to greater habitat diversity as well as a greater species diversity, and better conservation means of grassland in semi-arid areas.