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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

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.

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. (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

Chapter in Book - Research

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

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

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., 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

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., & 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

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). 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

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

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., & 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

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

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). 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

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

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

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(Pt. 4), 1583-1608. doi: 10.1016/j.jclepro.2016.11.141

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

Tengku-Rozaina, T. M., & Birch, E. J. (2015). Effects of fractionation on melting and crystallisation profiles of hoki oil measured by DSC. Journal of Thermal Analysis & Calorimetry, 120(1), 395-402. doi: 10.1007/s10973-014-3995-9

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

Tengku-Rozaina, T. M., & Birch, E. J. (2014). Positional distribution of fatty acids on hoki and tuna oil triglycerides by pancreatic lipase and 13C NMR analysis. European Journal of Lipid Science & Technology, 116(3), 272-281. doi: 10.1002/ejlt.201300357

Yang, S., Simmonds, R. S., & Birch, E. J. (2014). Physicochemical characterization and thermal properties of lipids from R. opacus PD630. Food & Public Health, 4(3), 87-92. doi: 10.5923/j.fph.20140403.03

Teh, S.-S., Bekhit, A. E.-D., & Birch, J. (2014). Antioxidative polyphenols from defatted oilseed cakes: Effect of solvents. Antioxidants, 3(1), 67-80. doi: 10.3390/antiox3010067

Mungure, T. E., & Birch, E. J. (2014). Analysis of intact triacylglycerols in cold pressed canola, flax and hemp seed oils by HPLC and ESI-MS. SOP Transactions on Analytical Chemistry, 1(1), 48-61.

Teh, S.-S., & Birch, E. J. (2014). Effect of ultrasonic treatment on the polyphenol content and antioxidant capacity of extract from defatted hemp, flax and canola seed cakes. Ultrasonics Sonochemistry, 21(1), 346-353. doi: 10.1016/j.ultsonch.2013.08.002

Rashidinejad, A., Birch, E. J., Sun-Waterhouse, D., & Everett, D. W. (2014). Delivery of green tea catechin and epigallocatechin gallate in liposomes incorporated into low-fat hard cheese. Food Chemistry, 156, 176-183. doi: 10.1016/j.foodchem.2014.01.115

Teh, S.-S., Bekhit, A. E.-D., Carne, A., & Birch, J. (2014). Effect of the defatting process, acid and alkali extraction on the physicochemical and functional properties of hemp, flax and canola seed cake protein isolates. Journal of Food Measurement & Characterization, 8(2), 92-104. doi: 10.1007/s11694-013-9168-x

Teh, S.-S., Niven, B. E., Bekhit, A. E.-D. A., Carne, A., & Birch, E. J. (2014). The use of microwave and pulsed electric field as a pretreatment step in ultrasonic extraction of polyphenols from defatted hemp seed cake (Cannabis sativa) using response surface methodology. Food & Bioprocess Technology, 7(11), 3064-3076. doi: 10.1007/s11947-014-1313-y

Gao, F., Yang, S., & Birch, E. J. (2014). Physicochemical characterization and thermal properties of Chinese Pinuskoraiensis nut oil and bioactive compounds from defatted Pinuskoraiensis nuts. SOP Transactions on Analytical Chemistry, 1(1), 26-39.

Rashidinejad, A., Birch, E. J., Sun-Waterhouse, D., & Everett, D. W. (2013). Effects of catechin on the phenolic content and antioxidant properties of low-fat cheese. International Journal of Food Science & Technology, 48(12), 2448-2455. doi: 10.1111/ijfs.12234

Teh, S.-S., & Birch, J. (2013). Physicochemical and quality characteristics of cold-pressed hemp, flax and canola seed oils. Journal of Food Composition & Analysis, 30(1), 26-31. doi: 10.1016/j.jfca.2013.01.004

Tengku-Rozaina, T. M., & Birch, E. J. (2013). Physicochemical characterisation and oxidative stability of refined hoki oil, unrefined hoki oil and unrefined tuna oil. International Journal of Food Science & Technology, 48(11), 2331-2339. doi: 10.1111/ijfs.12222

Tengku-Rozaina, T. M., & Birch, E. J. (2013). Enrichment of omega-3 fatty acids of refined hoki oil. Journal of the American Oil Chemists' Society, 90(8), 1111-1119. doi: 10.1007/s11746-013-2260-x

Ehimen, E. A., Sun, Z. F., Carrington, C. G., Birch, E. J., & Eaton-Rye, J. J. (2011). Anaerobic digestion of microalgae residues resulting from the biodiesel production process. Applied Energy, 88(10), 3454-3463. doi: 10.1016/j.apenergy.2010.10.020

Birch, J., Yap, K., & Silcock, P. (2010). Compositional analysis and roasting behaviour of gevuina and macadamia nuts. International Journal of Food Science & Technology, 45(1), 81-86. doi: 10.1111/j.1365-2621.2009.02106.x

Han, J., Silcock, P., Bell, M., & Birch, J. (2010). Lipase-catalyzed production of biodiesel from tallow. Journal of ASTM International, 7(1). doi: 10.1520/JAI102546

Choo, W.-S., Birch, E. J., & Stewart, I. (2009). Radical scavenging activity of lipophilized products from transesterification of flaxseed oil with cinnamic acid or ferulic acid. Lipids, 44(9), 807-815. doi: 10.1007/s11745-009-3334-2

Jansen, M., & Birch, J. (2009). Composition and stability of olive oil following partial crystallization. Food Research International, 42(7), 826-831. doi: 10.1016/j.foodres.2009.03.013

Choo, W.-S., & Birch, E. J. (2009). Radical scavenging activity of lipophilized products from lipase-catalyzed transesterification of triolein with cinnamic and ferulic acids. Lipids, 44(2), 145-152. doi: 10.1007/s11745-008-3242-x

Choo, W. S., Birch, E. J., & Dufour, J. P. (2007). Physicochemical and stability characteristics of flaxseed oils during pan-heating. Journal of the American Oil Chemists' Society, 84(8), 735-740.

Choo, W.-S., Birch, J., & Dufour, J.-P. (2007). Physicochemical and quality characteristics of cold-pressed flaxseed oils. Journal of Food Composition & Analysis, 20, 202-211.

Lim, M., Wu, H., Breckell, M., & Birch, J. (2006). Influence of the glass transition and storage temperature of frozen peas on the loss of quality attributes. International Journal of Food Science & Technology, 41, 507-512.

Ling, H.-I., Birch, J., & Lim, M. (2005). The glass transition approach to determination of drying protocols for colour stability in dehydrated pear slices. International Journal of Food Science & Technology, 40, 921-927.

Birch, J., McNab, R., Lim, M., Dufour, J.-P., & Carrington, G. (2004). Assessment of apple quality following dehydration using a heat pump dehumidifier system under conventional and modified atmosphere conditions. Food New Zealand, 4(4, Suppl.), 29-34.

Jia, Y., & Birch, E. J. (2003). A rapid test for the antioxidant status of green and black tea extracts in hot tallow. Food New Zealand, Nov/Dec(Suppl.), 29-33.

Tie, I. M. E., Birch, E. J., & Prescott, J. (2002). Physical measurements and sensory evaluation of oil used to deep-fry chips (French fries). Food New Zealand, 2(1), 51-58.

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