Projects

Post graduate (M.Sc) thesis title: Quality and elemental characterization of common spices of Bangladesh using nuclear reactor based NAA and gamma irradiation techniques

Supervisor

Dr. Ruhul Amin Khan, PhD (England), Post Doc (Canada) Visiting Scholar (California, USA)

Director, Institute of Radiation and Polymer Technology, Atomic Energy Research Establishment, Dhaka, Bangladesh. Contract no: +8801618585111 Email: dr.ruhul_khan@yahoo.com

Co-Supervisor

Dr. Mohammad Amirul Islam, PhD (Japan), Post Doc (Japan)

Principle Scientific Officer, Reactor & Neutron Physics Division, Atomic Energy Research Establishment, Dhaka, Bangladesh. Contact No: +8801712976542 E-mail: liton80m@yahoo.com

SUMMARY: Elemental characterization and gamma irradiation technique for bacterial decontamination of common spices available in Bangladesh were evaluated. Total concentrations of 17 essential and toxic elements (Al, As, Br, Ca, Cd, Cl, Co, Cr, Fe, K, Mn, Na, Ni, Pb, Sc, V and Zn) in spices were determined by research reactor-based neutron activation analysis (NAA) and atomic absorption spectrometry (AAS) techniques. This study indicates that spices are a good source of a combination of the essential elements-Ca, Fe, K, Mn, Na and Zn. This study revealed that concentrations of some toxic elements As, Cd, Cr and Pb in some spices were higher than the WHO/ FAO permissible levels. However, health risks associated with these elements evaluated by dietary intake, target hazard quotient and target carcinogenic risk indices indicate that people would experience no potential risks due to consumption of the spices. This study also evaluated the effect of gamma radiation on the decontamination of the microbial population, physicochemical, nutritional and sensory quality of spices during storage. Spices were irradiated with gamma doses of 0 (as control), 2, 4, 6, 8 and 10 kGy, packed in the glass vials and then stored at room temperature (22±2⁰C) and different properties were measured after 6 months. In this investigation, major food borne disease-producing organisms like Bacillus, Salmonella and Listeria species were identified in spice samples by molecular approaches. The results of this study indicated that gamma irradiations with increased doses significantly reduce the population of organisms compared to control and optimum gamma irradiation doses (6 kGy for red chili and turmeric; 4 kGy for cumin, coriander, garlic and black pepper; 2 kGy for ginger powder) were identified for decontamination of the microorganisms in the studied spices.

Undergraduate (B.Sc) thesis: Comparison on physicochemical properties of cabinet dried green chili (capsicum annum) and red chili powder

Supervisor

Prof. Dr. Md. Sazzat Hossain Sarker, PhD (Malaysia)

Chairman, Department of Food Engineering & Technology, Hajee Mohammad Danesh Science and Technology University (HSTU), Dinajpur, Bangladesh

Email: mshsarker@hstu.ac.bd. Contract no: +8801705950003

SUMMARY: The research was carried out to find suitable technology for the preparation of green chili powder and to compare the physicochemical properties of green and red chili powder. Green and red chili was collected from the local market, destalked, cleaned and five sets of sample were prepared for this study. The drying characteristics of all samples were evaluated. It was observed that the untreated sample took the maximum time (21 hrs.) to reach equilibrium condition whereas pretreated samples took the minimum time (16 hrs.). The physicochemical properties in terms of proximate composition, vitamin-C, color parameters, chlorophyll, beta-carotene and total phenol contents of green chili powder were also assessed. The moisture content of treated and untreated green chili powder samples was ranged 7.49% to 8.45% and found to be statistically similar at 5% level of significance. Vitamin C content was retained around 58% in all samples while chlorophyll, beta-carotene and total phenol contents were significantly increased as compared to the fresh green chili. The color measurement revealed that sample-2 retained the maximum green color as compared to other samples. The study has demonstrated that green chili powder obtained from sample gave the best results considering retention of color, and overall nutritional quality. Notably, sample was a new technology for processing of green chili powder. The results showed that the nutritional quality in all the samples of green chili powder was better than that of the red chili powder.