Dr Yacine Hemar

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Associate Professor

Research | Current

My research interests are related to the physical-chemical characterisation of food systems such as proteins and polysaccharides and their mixtures in solution, gel or emulsion states. Of specific interest the Structure-Function properties of biopolymer networks, and how these properties are affected by different stressors, such as shear, heat, pH etc.

  • Milk Protein, Polysaccharides and Milk Protein-Polysaccharide Interactions
    The aim of this activity is to characterise the physico-chemical characterisation of proteins and polysaccharides and their mixtures, using a battery of analytical methods, including rheology and scattering techniques. The characterisation exercise is performed with the view of relating the microscopic properties to the macroscopic mechanical behaviour of these systems.
  • Encapsulation, Release and Digestion of Bioactives
    We are currently investigating  the use of different technologies for the encapsulation and the target release of food bioactives. The physical behaviour of the encapsulating system and the release kinetics of the bioactive during digestion are investigated in-vitro under simulated gastrointestinal conditions.  This activity is part of a broader research area on the “rheo-physiology of structured foods”.
  • Novel Process Technologies
    We are interested by the effect of Novel Process Technologies, such as High Hydrostatic Pressure, Pulsed Electric Field and Ultrasound on the physico-chemical properties of food systems.  We are also currently developing methodologies to the real-time in-situ investigation of food-based systems when subjected to the stresses (electro-mechanical, pressure, cavitation effects etc...) resulting from the application of these Processes.
  • Development of Light Scattering Techniques to characterise Food Systems
    In the recent years we developed Diffusing Wave Spectroscopy (DWS) as a particle sizing method for concentrated dispersions. In addition, we have used DWS to measure the micro-rheological, high-frequency, behaviour of biopolymer systems, and to investigate the mechanical behaviour of fluids under shear. Currently we are extending this capability to Multiple Speckle Diffusing-Wave Spectroscopy (MSDWS), a CCD-Camera based technique, for the study of non-ergodic media.

Responsibilities

Director of Food Science
 

Selected publications and creative works (Research Outputs)

  • Li, Z., Scott, K., Hemar, Y., Zhang, H., & Otter, D. (2018). Purification and characterisation of a protease (tamarillin) from tamarillo fruit. Food chemistry, 256, 228-234. 10.1016/j.foodchem.2018.02.091
  • Li, Z., Scott, K., Hemar, Y., & Otter, D. (2018). Protease activity of enzyme extracts from tamarillo fruit and their specific hydrolysis of bovine caseins. Food Research International, 109, 380-386. 10.1016/j.foodres.2018.04.039
  • Hauptstein, N., De Leon Rodriguez, L. M., Mitra, A. K., Hemar, Y., Kavianinia, I., Li, N., ... Brimble, M. A. (2018). Supramolecular Threading of Peptide Hydrogel Fibrils. ACS Biomaterials Science & Engineering10.1021/acsbiomaterials.8b00283
    Other University of Auckland co-authors: Luis De Leon Rodriguez, Margaret Brimble, Iman Kavianinia
  • Li, Z., Scott, K., Otter, D., Zhou, P., & Hemar, Y. (2018). Effect of temperature and pH on the properties of skim milk gels made from a tamarillo (Cyphomandra betacea) coagulant and rennet. Journal of dairy science, 101 (6), 4869-4878. 10.3168/jds.2017-14050
    Other University of Auckland co-authors: Zhao Li
  • Li, Z., Yang, Z., Otter, D., Rehm, C., Li, N., Zhou, P., & Hemar, Y. (2018). Rheological and structural properties of coagulated milks reconstituted in D2O: Comparison between rennet and a tamarillo enzyme (tamarillin). FOOD HYDROCOLLOIDS, 79, 170-178. 10.1016/j.foodhyd.2017.12.004
    Other University of Auckland co-authors: Zhi Yang
  • Yang, Z., Gu, Q., Banjar, W., Li, N., & Hemar, Y. (2018). In situ study of skim milk structure changes under high hydrostatic pressure using synchrotron SAXS. Food Hydrocolloids, 77, 772-776. 10.1016/j.foodhyd.2017.11.019
    Other University of Auckland co-authors: Zhi Yang
  • Alzahrani, M. A. J., Perera, C. O., & Hemar, Y. (2018). Production of bioactive proteins and peptides from the diatom Nitzschia laevis and comparison of their in vitro antioxidant activities with those from Spirulina platensis and Chlorella vulgaris. International Journal of Food Science & Technology, 53 (3), 676-682. 10.1111/ijfs.13642
    Other University of Auckland co-authors: Conrad Perera
  • Sinthusamran, S., Benjakul, S., & Hemar, Y. (2018). Physical and sensory properties of gelatin from seabass (Lates calcarifer) as affected by agar and κ-carrageenan. Journal of texture studies, 49 (1), 47-55. 10.1111/jtxs.12280

Contact details

Primary office location

SCIENCE CENTRE - CHEMISTRY - Bldg 301
Level 5, Room 508
23 SYMONDS ST
AUCKLAND 1010
New Zealand