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Zahra Zolfaghari

PhD Candidate
Food Science

Zahra Zolfaghari

Contact

Ext 8258
Email zahra.zolfghari@postgrad.otago.ac.nz
Location CSB 220

Characterization of unifloral honeys based on volatile compounds, physicochemical properties and bioactivity.

Supervised by Associate Professor John Birch and Dr Graham Eyres.

About

I completed my MSc at Ferdowsi University of Masahhad, in my home country of Iran.
Being a postgraduate student in the Food Science department is a wonderful experience because of the positive and active atmosphere among students and staff.
Being accepted into a PhD program at the University of Otago has allowed me to study at a highly respected University and experience another country. Dunedin is safe and friendly; it is a beautiful city with many green areas, bike routes, hiking tracks, scenic peninsula and amazing wildlife of penguins, sea lions, fur seals and petrels.

Project Outline

Unifloral honey is a premium product predominantly produced from one single nectar source valued for its distinctive sensory characteristics. Because of this higher commercial value, unifloral honeys are subject to fraud through mislabelling and mixing with cheaper honeys.

Traditionally, unifloral honey is judged based on melissopalynology (the identification and counting pollens in honey). This method requires expertise in pollen morphology and the availability of a comprehensive collection of reference pollen grains. Results of melissopalynology can be confounded as the pollen content of honey can be altered by the action of bees or contamination by the actions of apiarists. In some cases, pollens are not detectable or distinguishable from morphologically similar pollens by melissopalynology.

Honey contains high concentrations of sugars, water, minerals, proteins, vitamins, organic acids, flavonoids, phenolic acids and enzymes. These components not only define the physical properties of honey, they also present different patterns of saccharides, volatile compounds and phenolic compounds that give an indication of the botanical origin of honey.

My objective is to evaluate different criteria of characterising the properties and composition of unifloral honey including sugar profile, volatile compounds and chiral compounds in order to define typical characteristics of unifloral honeys.

Aroma is one of the typical features of honey and is largely dependent on volatile compounds that may come from the nectar or honeydew collected by bees. Therefore, screening volatile compounds may distinguish the floral origin.

I am applying two strategies to distinguish these compounds that may identify the floral origin. First, producing a volatile profile that represents a “finger print” of the product which is due to the floral origin using proton transfer reaction mass spectrometry (PTR-MS). My second strategy is identifying specific floral markers for each type of unifloral honey using gas chromatography-mass spectrometry (GC-MS).

Many volatile compounds present in honey are chiral and exist as pair of enantiomers. These chiral compounds are mostly synthesized in plants by enzymatic reactions, which are not dependant on the conditioning or storage of the honey. Therefore, they provide a tool to characterise the origin of unifloral honeys.  

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Publications

Okoro, O. V., Sun, Z., & Birch, J. (2019). Thermal depolymerization of biogas digestate as a viable digestate processing and resource recovery strategy. In K. Azad (Ed.), Advances in eco-fuels for a sustainable environment. (pp. 277-308). Duxford, UK: Woodhead Publishing. doi: 10.1016/B978-0-08-102728-8.00010-3

Okoro, O. V., Sun, Z., & Birch, J. (2019). Techno-economic assessment of a scaled-up meat waste biorefinery system: A simulation study. Materials, 12(7), 1030. doi: 10.3390/ma12071030

Zhang, H., Birch, J., Pei, J., Mohamed Ahmed, I. A., Yang, H., Dias, G., … Bekhit, A. E.-D. (2019). Identification of six phytochemical compounds from Asparagus officinalis L. root cultivars from New Zealand and China using UAE-SPE-UPLC-MS/MS: Effects of extracts on H2O2-induced oxidative stress. Nutrients, 11(1), 107. doi: 10.3390/nu11010107

Zhang, H., Birch, J., Ma, Z. F., Xie, C., Yang, H., Bekhit, A. E.-D., & Dias, G. (2019). Optimization of microwave-assisted extraction of bioactive compounds from New Zealand and Chinese Asparagus officinalis L. roots. Journal of Food Science & Technology, 56(2), 799-810. doi: 10.1007/s13197-018-3540-0

Amini Khoozani, A., Bekhit, A. E.-D. A., & Birch, J. (2019). Effects of different drying conditions on the starch content, thermal properties and some of the physicochemical parameters of whole green banana flour. International Journal of Biological Macromolecules, 130, 938-946. doi: 10.1016/j.ijbiomac.2019.03.010

Chapter in Book - Research

Okoro, O. V., Sun, Z., & Birch, J. (2019). Thermal depolymerization of biogas digestate as a viable digestate processing and resource recovery strategy. In K. Azad (Ed.), Advances in eco-fuels for a sustainable environment. (pp. 277-308). Duxford, UK: Woodhead Publishing. doi: 10.1016/B978-0-08-102728-8.00010-3

Rashidinejad, A., & Birch, J. (2018). Xanthine oxidase in dairy foods. In G. W. Smithers (Ed.), Reference module in food science. Elsevier. doi: 10.1016/B978-0-08-100596-5.21648-X

Mungure, T. E., Bekhit, A. E.-D., Carne, A., Roohinejad, S., Mallikarjunan, K., & Birch, J. (2018). Application of HPLC in characterisation of triacylglycerols and detection of adulteration in cold pressed seed oils. In G. W. Smithers (Ed.), Reference module in food science. Elsevier. doi: 10.1016/B978-0-08-100596-5.22526-2

Okoro, O. V., Sun, Z., & Birch, J. (2018). Lipases for biofuel production. In G. Smithers (Ed.), Reference module in food science. Elsevier. doi: 10.1016/B978-0-08-100596-5.21650-8

Amini Khoozani, A., Birch, J., & Bekhit, A. E.-D. A. (2018). Resistant starch preparation methods. In G. Smithers (Ed.), Reference module in food science. Elsevier. doi: 10.1016/B978-0-08-100596-5.22491-8

Tantamacharik, T., Carne, A., Agyei, D., Birch, J., & Bekhit, A. E.-D. A. (2018). Use of plant proteolytic enzymes for meat processing. In M. G. Guevara & G. R. Daleo (Eds.), Biotechnological applications of plant proteolytic enzymes. (pp. 43-67). Cham, Switzerland: Springer. doi: 10.1007/978-3-319-97132-2_3

Tengku-Rozaina, T. M., & Birch, E. J. (2018). Thermal analysis for lipid decomposition by DSC and TGA. In G. W. Smithers (Ed.), Reference module in food science. Elsevier. doi: 10.1016/B978-0-08-100596-5.21674-0

Lloyd, K., Mirosa, M., & Birch, J. (2018). Active and intelligent packaging. In G. W. Smithers (Ed.), Reference module in food science. Elsevier. doi: 10.1016/B978-0-08-100596-5.22421-9

Loi, C. C., Eyres, G. T., & Birch, E. J. (2018). Protein-stabilised emulsions. In G. Smithers (Ed.), Reference module in food science. Elsevier. doi: 10.1016/B978-0-08-100596-5.22490-6

Clarkson, C., Birch, J., & Mirosa, M. (2018). Locusts as a source of lipids and proteins and consumer acceptance. In G. Smithers (Ed.), Reference module in food science. Elsevier. doi: 10.1016/B978-0-08-100596-5.22420-7

Kanokruangrong, S., Birch, J., & Bekhit, A. E.-D. A. (2018). Processing effects on meat flavor. In G. Smithers (Ed.), Reference module in food science. Elsevier. doi: 10.1016/B978-0-08-100596-5.21861-1

Rashidinejad, A., Bremer, P., Birch, J., & Oey, I. (2017). Nutrients in cheese and their effect on health and disease. In R. R. Watson, R. J. Collier & V. R. Preedy (Eds.), Nutrients in dairy and their implications for health and disease. (pp. 177-192). London, UK: Academic Press.

Birch, J., & Bell, M. (2010). Biodiesel: Enzymatic production. In D. R. Heldman, M. B. Wheeler & D. G. Hoover (Eds.), Encyclopedia of biotechnology in agriculture and food. CRC Press.

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Chapter in Book - Other

Han, J., Silcock, P., Bell, M., & Birch, J. (2011). Lipase-catalyzed production of biodiesel from tallow [Reprint from Journal of ASTM International (2010) 7(1). doi: 10.1520/STP49365S

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Journal - Research Article

Okoro, O. V., Sun, Z., & Birch, J. (2019). Techno-economic assessment of a scaled-up meat waste biorefinery system: A simulation study. Materials, 12(7), 1030. doi: 10.3390/ma12071030

Zhang, H., Birch, J., Ma, Z. F., Xie, C., Yang, H., Bekhit, A. E.-D., & Dias, G. (2019). Optimization of microwave-assisted extraction of bioactive compounds from New Zealand and Chinese Asparagus officinalis L. roots. Journal of Food Science & Technology, 56(2), 799-810. doi: 10.1007/s13197-018-3540-0

Amini Khoozani, A., Bekhit, A. E.-D. A., & Birch, J. (2019). Effects of different drying conditions on the starch content, thermal properties and some of the physicochemical parameters of whole green banana flour. International Journal of Biological Macromolecules, 130, 938-946. doi: 10.1016/j.ijbiomac.2019.03.010

Zhang, H., Birch, J., Pei, J., Mohamed Ahmed, I. A., Yang, H., Dias, G., … Bekhit, A. E.-D. (2019). Identification of six phytochemical compounds from Asparagus officinalis L. root cultivars from New Zealand and China using UAE-SPE-UPLC-MS/MS: Effects of extracts on H2O2-induced oxidative stress. Nutrients, 11(1), 107. doi: 10.3390/nu11010107

Zhang, H., Birch, J., Pei, J., Feei Ma, Z., Xie, C., Yang, H., & Bekhit, A. E.-D. (2019). Optimization of ultrasound assisted extraction method for phytochemical compounds and in-vitro antioxidant activity of New Zealand and China Asparagus cultivars (officinalis L.) roots extracts. Food Chemistry. Advance online publication. doi: 10.1016/j.foodchem.2019.03.012

Loi, C. C., Eyres, G. T., & Birch, E. J. (2019). Effect of milk protein composition on physicochemical properties, creaming stability and volatile profile of a protein-stabilised oil-in-water emulsion. Food Research International. Advance online publication. doi: 10.1016/j.foodres.2019.02.026

Zhang, H., Birch, J., Xie, C., Yang, H., Dias, G., Kong, L., & Bekhit, A. E.-D. (2018). Optimization of extraction parameters of antioxidant activity of extracts from New Zealand and Chinese Asparagus officinalis L root cultivars. Industrial Crops & Products, 119, 191-200. doi: 10.1016/j.indcrop.2018.03.066

Loi, C. C., Eyres, G. T., & Birch, E. J. (2018). Effect of mono- and diglycerides on physical properties and stability of a protein-stabilised oil-in-water emulsion. Journal of Food Engineering. Advance online publication. doi: 10.1016/j.jfoodeng.2018.07.016

Tengku-Rozaina, T. M., & Birch, E. J. (2018). Effects of low temperature solvent fractionation on the thermal oxidative stability and antioxidant activity of refined hoki oil and its derived fractions. European Journal of Lipid Science & Technology. Advance online publication. doi: 10.1002/ejlt.201800140

Clarkson, C., Mirosa, M., & Birch, J. (2018). Potential of extracted Locusta migratoria protein fractions as value-added ingredients. Insects, 9(1), 20. doi: 10.3390/insects9010020

Bekhit, A. E.-D. A., Shavandi, A., Jodjaja, T., Birch, J., Teh, S., Ahmed, I. A. M., … Saeedi, P., & Bekhit, A. A. (2018). Flaxseed: Composition, detoxification, utilization, and opportunities. Biocatalysis & Agricultural Biotechnology, 13, 129-152. doi: 10.1016/j.bcab.2017.11.017

Clarkson, C., Mirosa, M., & Birch, J. (2018). Consumer acceptance of insects and ideal product attributes. British Food Journal, 120(12), 2898-2911. doi: 10.1108/bfj-11-2017-0645

Zhang, H., Birch, J., Yang, H., Xie, C., Kong, L., Dias, G., & Bekhit, A. E.-D. (2018). Effect of solvents on polyphenol recovery and antioxidant activity of isolates of Asparagus Officinalis roots from Chinese and New Zealand cultivars. International Journal of Food Science & Technology, 53(10), 2369-2377. doi: 10.1111/ijfs.13829

Okoro, O. V., Sun, Z., & Birch, J. (2018). Experimental evaluation of a polystyrene sulphonic acid resin catalyst in the hydrolysis of low-grade lipids from the meat processing industry. Biomass & Bioenergy, 116, 49-59. doi: 10.1016/j.biombioe.2018.06.001

Okoro, O. V., Sun, Z., & Birch, J. (2018). Prognostic assessment of the viability of hydrothermal liquefaction as a post-resource recovery step after enhanced biomethane generation using co-digestion technologies. Applied Sciences, 8(11), 2290. doi: 10.3390/app8112290

Okoro, O. V., Sun, Z., & Birch, J. (2018). Catalyst-free biodiesel production methods: A comparative technical and environmental evaluation. Sustainability, 10(1), 127. doi: 10.3390/su10010127

Okoro, O. V., Sun, Z., & Birch, J. (2017). Meat processing dissolved air flotation sludge as a potential biodiesel feedstock in New Zealand: A predictive analysis of the biodiesel product properties. Journal of Cleaner Production, 168, 1436-1447. doi: 10.1016/j.jclepro.2017.09.128

Rashidinejad, A., Birch, E. J., Sun-Waterhouse, D., & Everett, D. W. (2017). Addition of milk to tea infusions: Helpful or harmful? Evidence from in vitro and in vivo studies on antioxidant properties. Critical Reviews in Food Science & Nutrition, 57(15), 3188-3196. doi: 10.1080/10408398.2015.1099515

Tirgar, M., Silcock, P., Carne, A., & Birch, E. J. (2017). Effect of extraction method on functional properties of flaxseed protein concentrates. Food Chemistry, 215, 417-424. doi: 10.1016/j.foodchem.2016.08.002

Rashidinejad, A., Birch, E. J., Hindmarsh, J., & Everett, D. W. (2017). Molecular interactions between green tea catechins and cheese fat studied by solid-state nuclear magnetic resonance spectroscopy. Food Chemistry, 215, 228-234. doi: 10.1016/j.foodchem.2016.07.179

Okoro, O. V., Sun, Z., & Birch, J. (2016). Meat processing waste as a potential feedstock for biochemicals and biofuels: A review of possible conversion technologies. Journal of Cleaner Production, 142(Part 4), 1583-1608. doi: 10.1016/j.jclepro.2016.11.141

Teh, S.-S., Bekhit, A. E.-D. A., Carne, A., & Birch, J. (2016). Antioxidant and ACE-inhibitory activities of hemp (Cannabis sativa L.) protein hydrolysates produced by the proteases AFP, HT, Pro-G, actinidin and zingibain. Food Chemistry, 203, 199-206. doi: 10.1016/j.foodchem.2016.02.057

Rashidinejad, A., Birch, E. J., & Everett, D. W. (2016). Interactions between milk fat globules and green tea catechins. Food Chemistry, 199, 347-355. doi: 10.1016/j.foodchem.2015.12.030

Rashidinejad, A., Birch, E. J., & Everett, D. W. (2016). A novel functional full-fat hard cheese containing liposomal nanoencapsulated green tea catechins: Manufacture and recovery following simulated digestion. Food & Function, 7, 3283-3294. doi: 10.1039/c6fo00354k

Tengku-Rozaina, T. M., & Birch, E. J. (2016). Thermal oxidative stability analysis of hoki and tuna oils by differential scanning calorimetry and thermogravimetry. European Journal of Lipid Science & Technology, 118(7), 1053-1061. doi: 10.1002/ejlt.201500310

Rashidinejad, A., Birch, E. J., Sun-Waterhouse, D., & Everett, D. W. (2016). Effect of liposomal encapsulation on the recovery and antioxidant properties of green tea catechins incorporated into a hard low-fat cheese following in vitro simulated gastrointestinal digestion. Food & Bioproducts Processing, 100(Part A), 238-245. doi: 10.1016/j.fbp.2016.07.005

Rashidinejad, A., Birch, E. J., & Everett, D. W. (2016). The behaviour of green tea catechins in a full-fat milk system under conditions mimicking the cheesemaking process. International Journal of Food Sciences & Nutrition, 67(6), 624-631. doi: 10.1080/09637486.2016.1195797

Rashidinejad, A., Birch, E. J., & Everett, D. W. (2016). Green tea catechins suppress xanthine oxidase activity in dairy products: An improved HPLC analysis. Journal of Food Composition & Analysis, 48, 120-127. doi: 10.1016/j.jfca.2016.03.001

Mungure, T. E., Bekhit, A. E.-D. A., Birch, E. J., & Stewart, I. (2016). Effect of rigour temperature, ageing and display time on the meat quality and lipid oxidative stability of hot boned beef Semimembranosus muscle. Meat Science, 114, 146-153. doi: 10.1016/j.meatsci.2015.12.015

Gao, F., Yang, S., & Birch, J. (2016). Physicochemical characteristics, fatty acid positional distribution and triglyceride composition in oil extracted from carrot seeds using supercritical CO2. Journal of Food Composition & Analysis, 45, 26-33. doi: 10.1016/j.jfca.2015.09.004

Gao, F., & Birch, J. (2016). Oxidative stability, thermal decomposition, and oxidation onset prediction of carrot, flax, hemp, and canola seed oils in relation to oil composition and positional distribution of fatty acids. European Journal of Lipid Science & Technology, 118(7), 1042-1052. doi: 10.1002/ejlt.201500208

Rashidinejad, A., Birch, E. J., & Everett, D. W. (2016). Effects of (+)-Catechin on the composition, phenolic content and antioxidant activity of full-fat cheese during ripening and recovery of (+)-Catechin after simulated in vitro digestion. Antioxidants, 5(3), 29. doi: 10.3390/antiox5030029

Rashidinejad, A., Birch, E. J., & Everett, D. W. (2016). Antioxidant activity and recovery of green tea catechins in full-fat cheese following gastrointestinal simulated digestion. Journal of Food Composition & Analysis, 48, 13-24. doi: 10.1016/j.jfca.2016.02.004

Rashidinejad, A., Birch, E. J., Sun-Waterhouse, D., & Everett, D. W. (2015). Total phenolic content and antioxidant properties of hard low-fat cheese fortified with catechin as affected by in vitro gastrointestinal digestion. LWT, 62(1, Part 2), 393-399. doi: 10.1016/j.lwt.2014.12.058

Teh, S.-S., Niven, B. E., Bekhit, A. E.-D. A., Carne, A., & Birch, J. (2015). Optimization of polyphenol extraction and antioxidant activities of extracts from defatted flax seed cake (Linum usitatissimum L.) using microwave-assisted and pulsed electric field (PEF) technologies with response surface methodology. Food Science & Biotechnology, 24(5), 1649-1659. doi: 10.1007/s10068-015-0214-9

Teh, S.-S., Niven, B. E., Bekhit, A. E.-D. A., Carne, A., & Birch, E. J. (2015). Microwave and pulsed electric field assisted extractions of polyphenols from defatted canola seed cake. International Journal of Food Science & Technology, 50, 1109-1115. doi: 10.1111/ijfs.12749

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