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Item EVALUATION OF DRYING CHARACTERISTICS AND QUALITY OF MAIZE DRIED BY TWO STAGE DRYING TECHNIQUES(HAJEE MOHAMMAD DANESH SCIENCE AND TECHNOLOGY UNIVERSITY, DINAJPUR., 2018-03) Akhtaruzzaman, Md.; Prof. Dr. Md. Sazzat Hossain SarkerDrying of freshly harvested maize is a great concern in all maize producing countries. This research was conducted to investigate suitable and efficient two-stage drying options for high moisture maize. First option was employed by fluidized bed drying and tempering followed by sun drying method and second option was carried out in fluidized bed dryer using variable temperature i.e fluidized bed drying at high temperature and tempering followed by further fluidized bed drying at low temperature. First stage drying in fluidized bed dryer was carried out using three temperatures (120, 140 and 1600C) at constant bed thickness of 7.0 cm. After first stage drying, all dried samples were immediately tempered for 45 minutes at grain temperature. Further, all the tempered samples were dried in second stage by sun drying method and in the same fluidized bed dryer using 65 ± 20C, respectively in first and second option of two stage drying. Drying performances in terms of drying time, effective moisture diffusivity and specific energy consumption of the drying options and quality of dried maize were evaluated. Drying results indicated that total drying time required 4.25 hours in first option and 1.41 hours in second option of two-stage drying technique. On the other hand, total drying time for single stage drying (complete sun drying method) required 10 hours. Effective moisture diffusivity of maize kernel was found to be ranged from1.05×10-08 m 2 /s to 1.15×10-08 m 2 /s and 4.4×10-08 m 2 /s to 6.3×10-08 m 2 /s in first and second option, respectively. Specific electrical energy consumption in terms of primary energy and specific thermal energy consumption varied from 0.13 MJ/kg to 0.35 MJ/kg and 0.28 MJ/kg to 0.68 MJ/kg water evaporated for the first stage of fluidized bed drying. Physical properties such bulk density and porosity of the dried product varied between two stage drying and sun drying option. Total color difference of the dried maize obtained from both the two stage drying options was higher (6.32±1.11) in contrast to the sun dried sample (3.64±0.49). The values of % crude protein (6.24±0.27) and % starch content (69.20±0.96) increased during two stages drying whereas amylose content (19.05±0.30 mg/100g) and β-carotene content (0.14±0.02) were found to be decreased in compare to control drying. Even though both the options yielded almost same quality dried product yet second option is preferable for quick drying using lower energy. Therefore, the proposed two-stage drying can be introduced as alternating drying techniques for high moisture maize in commercial drying complexes of Bangladesh. However, further study is required for design and development of commercial dryers to be used at farm level.Item OPTIMIZATION OF OSMOTIC DEHYDRATION OF CARROT SLICES UNDER PULSED VACUUM CONDITION IN TERNARY SOLUTION BY RESPONSE SURFACE METHODOLOGY(HAJEE MOHAMMAD DANESH SCIENCE AND TECHNOLOGY UNIVERSITY, DINAJPUR., 2016-12) HOQUE, A.K.M. MONGURUL; Md. Raihanul HaqueThe osmotic dehydration (OD) is a treatment in which large portion moisture is removed to obtain minimally processed product. The use of reduced pressure at the beginning of the process is called pulsed vacuum osmotic dehydration (PVOD). In this present work, the influence of independent variables (temperature, salt, and sucrose concentration, and restoration time) on water loss (WL), solute gain (SG) and color change (CC) of carrot slices was studied by response surface methodology. Analysis of results showed that restoration time was the most significant variables (p<0.05) for WL and SG while temperature significantly influenced the Change of color parameter. The optimum operating conditions were found to be restoration time of 182.50 min, solution temperature of 40.55°C, and solution concentration of 46.88oBrix sucrose with 12.50% sodium chloride. Under this operating condition WL, SG and CC were 52.3964% (wb), 11.68% (wb) and 5.98, respectively. The predicted values for independent variables were validated by performing several experiments and the simulated data were found similar to the experimental ones.Item OPTIMIZATION OF PROCESS PARAMETERS DURING PULSED MICROWAVE OSMOTIC DEHYDRATION (PMOD) OF BANANA SLICES BY RESPONSE SURFACE METHODOLOGY(HAJEE MOHAMMAD DANESH SCIENCE AND TECHNOLOGY UNIVERSITY, DINAJPUR., 2016-12) ISLAM, MD. RAKIBUL; Md. Raihanul HaqueThe pulsed microwave osmotic dehydration (PMOD) of banana slices was carried out by immersing in sucrose solution. The experiments were conducted using a face-centered central composite design (FCCD) with four factors, viz. slice thickness (5-10 mm), sucrose concentration (40-60oBrix), microwave power (100-1000W), and time (10-50 min) at three levels to take into account the individual and interaction effects of the factors. The sample to solution ratio of 1:30 was kept constant throughout all of the experiments to minimize the cost of processing. Optimization of the process parameters for osmotic dehydration of banana slices was also obtained by response surface methodology. Multiple regression analysis showed that all process factors highly affect linearly on the water loss (WL), solid gain (SG), drying efficiency (DE), and color change (ΔE). Microwave power was found as the most significant factor during pulsed microwave osmotic dehydration (PMOD) of banana slices except for water loss (WL) in which osmosis time was found as the most influential factor (p<0.01). The optimum operating conditions were found to be slice thickness of 9.94 mm, sucrose concentration of 60oBrix, microwave power level of 100W, and time of osmosis of 50 min. Under this operating condition WL, SG and color change were 19.49 % (wb), 6.96% (wb) and 15.06, respectively. The predicted optimum values for independent variables were validated by performing several experiments and the simulated data were found in closeness to the experimental ones.Item DRYING OF AROMATIC RICE IN FLUIDIZED BED DRYER FOLLOWED BY FIXED BED DRYER AND SUN DRYING METHOD(HAJEE MOHAMMOD DANESH SCIENCE AND TECHNOLOGY UNIVERSITY, DINAJPUR, 2016-12) ROY, GOUTAM CHANDRA; Dr. Md. Sazzat Hossain SarkerDrying and management of aromatic rice (Oryza sativa L.) are important issues because of its increased demand in Bangladesh. Feasibility of two-stage drying of aromatic rice (locally known as Chinigura) and the effects of the drying technique on milling quality were investigated. The milling quality of dried aromatic rice was compared with existing industrial milling results where Louisiana State University (LSU) dryer was used. A laboratory fluidized bed dryer was used for the first stage drying to reduce the initial high moisture content of 22-24% (wb) to 18-19% (wb). A fixed bed dryer and sun drying method were used for the second stage drying for further drying of paddy up to the milling level of 14% (wb) or less. The thicknesses in fluidized bed drying were 8 cm, 10 cm and 12 cm. Three drying air temperatures of 65°C, 85°C and 100°C were applied for each bed thickness. The fixed bed dryer was operated at the temperature of 400C and fixed bed thickness of 30 cm. The tempering of paddy was done at product’s temperature in a closed container for 30 minutes of each dried samples after first stage drying in the fluidized bed dryer. Shorter drying time (4.33 to 4.67 hr) required in application of the two stage drying technique contrast to drying time needed by industrial method (10-12 hours). Two stage drying employing fluidized bed drying and sun drying yielded to 0.6% to 17.35% higher head rice yield than existing industrial drying method. On the other hand, two stage drying with fluidized bed dryer followed by fixed bed dryer gave 4.45% to 14.2% higher head rice yield than industrial drying method. The bed thickness and drying temperature had significant effect on the quality of aromatic rice. On the other hand, milling recovery, whiteness in terms of lightness (L*) and aroma of dried aromatic rice samples were insignificantly varried for all tested samples. Therefore, two-stage drying technique equipped with fluidized bed dryer may be recommended for drying of aromatic rice to save drying time as well as energy.Item TWO-STAGE DRYING FOR RAPID MANAGEMENT OF HIGH MOISTURE MAIZE(HAJEE MOHAMMOD DANESH SCIENCE AND TECHNOLOGY UNIVERSITY, DINAJPUR, 2016-09) ROSHID, MD. MAMUNUR; Dr. Md. Sazzat Hossain SarkerManagement of high moisture maize grains is a problem in Bangladesh. This study was conducted to investigate the feasibility of two options of two-stage drying of maize: i) fluidized bed drying (FBD) and tempering followed by sun drying method and ii) fluidized bed drying (FBD) and tempering followed by fixed bed drying method. An experimental fixed bed dryer was designed and fabricated for using in second stage drying under this study while a previously developed laboratory scale fluidized bed dryer was used for first stage drying of the samples. The fixed bed dryer consists of a rectangular shaped drying chamber with the dimension of 25 × 25 × 100 cm. It has a blower that produces maximum air flow rate 0.10 m3 /s and a heating unit composed of three electric heaters (1.5 kW each) separately connected. The blower was driven by a 2 hp motor of 1440 rpm. The fluidized bed drying of maize samples was carried out using three temperatures (100, 130 and 1500C) at three bed thickness (7, 9 and 11cm). After first stage drying, all dried samples were immediately tempered for 45 minutes at grain temperature. Further, all the tempered samples were dried in second stage drying in the fixed bed dryer using 45 ± 20C temperature at 30 cm bed thickness and by sun drying method separately. Total drying time required 4.57 hours for first option and 2.57 hours for second option of two-stage drying technique. On the other hand, total drying time for single stage drying (complete sun drying method) required 11.25 hours. The proposed two-stage drying technique exhibited as a quicker method than existing drying method of maize. The results showed that most of the drying parameters of fluidized bed drying were suitable for maize drying in employing both the options. The highest nutritional quality in terms of protein content (6.65% to 6.67%) and ash content (1.17% to 1.18%) was obtained in the dried samples dried using 1300C at 9 cm bed thickness. Better grain colour was also found in that drying condition while the colour values were: L* = 67.5 to 70.9; b* = 43.1 to 43.3; and a* = 7.9 to 8.0. The calculation revealed that the microbial load of dried maize for the first option and second option methods were 2.68 × 105 to 1.59 × 106 cfu/g and 3.0 × 103 to 3.2 × 103 cfu/g, respectively. Thus, it is clear that both the methods were almost similar based on physical and nutritional quality but in term of microbial load, the second option was more hygienic than the first option. Hence, for quality and hygienic dried product, high moisture maize should be dried in fluidized bed dryer using 1300C temperature and 9cm bed thickness in first stage drying then by fixed bed dryer. Therefore, two-stage drying may be recommended for drying of high moisture maize and other cereals in commercial scale.Item EFFECT OF PRETREATMENTS AND STORAGE TEMPERATURES ON PHYSICO-CHEMICAL AND FUNCTIONAL PROPERTIES OF CARROT POWDER(HAJEE MOHAMMOD DANESH SCIENCE AND TECHNOLOGY UNIVERSITY, DINAJPUR, 2016-12) DAS, KATHIKA; Habiba KhatunDrying of vegetable after chemical pretreatment has long been an effective method of preservation. The objective of this study was to find out suitable pretreatment and storage temperature for cabinet dried carrot powder based on physico-chemical and functional properties. Drying process was carried out for carrot cubes (0.3-0.5cm) using four blanching (80±2ºC) pretreatments such as blanching with 1% calcium chloride (CaCl2), 0.2% potassium metabisulphite (KMS), 1% calcium chloride and 0.2% potassium metabisulphite (CaCl2+KMS) combination and pure water. An untreated sample was considered as control. Then all the pretreated samples were dried in cabinet dryer at 60±2ºC temperature for 18 hours and the dried samples were ground as powder. The entire obtained carrot powder sample were packed in low density polyethylene and stored at three storage temperatures such as ambient temperature (20±2ºC), refrigeration temperature (4±2ºC) and freezing temperature (-10±2ºC). The dried samples were analyzed for physico-chemical properties in terms of moisture, ash, fat, protein, fiber, beta-carotene and color and functional properties such as degree of caking, water absorption index, rehydration ratio, swelling capacity, bulk density and solubility at 0 day, 30 days and 60 days of storage. Results revealed that the moisture content of carrot powder treated with KMS and stored in freezing temperature was found to be lower than that of other pretreatments and storage temperatures. In case of fat, protein, ash, fiber and beta-carotene content, there were significant (at p≤0.001) effects of pretreatments and storage temperatures on carrot powder. Carrot powder treated with KMS and stored at freezing temperature was recorded to have better nutritional composition in terms of protein, fiber and betacarotene compared to that of other pretreatments and storage temperatures. On the other hand, all the functional properties of carrot powder were showed to be significantly (at p≤0.001) different due to different pretreatments and storage temperatures. Sample treated with KMS and stored at freezing temperature was reported to show better functional properties than that of other pretreatments and storage temperatures. The overall results indicated that physico-chemical and functional properties of cabinet dried carrot powder can be maintained well if the sample is treated with 0.2% KMS before drying and stored at freezing temperature.Item EFFECTS OF SPINACH (Spinacia oleracea) POWDER ON THE PHYSICAL, PHYSIOCHEMICAL AND SENSORY QUALITIES OF BISCUITS(HAJEE MOHAMMAD DANESH SCIENCE AND TECHNOLOGY UNIVERSITY, DINAJPUR., 2018-06) RUMPA, ARMIN CHOWDHURY; Prof. Dr. Md. Sazzat Hossain SarkerLow-calorie and high-fiber vegetable powder supplemented biscuits have a great demand among the biscuit consumers. Therefore, an attempt was undertaken to prepare composite biscuit supplementing wheat flour by spinach powder. A multistoried universal cabinet dryer, developed in the laboratory of Food Engineering and Technology department, was used to dry raw spinach at a temperature of 55-60 0C and powder was prepared by grinding and sieving through 300 MSI mesh. The powder was found to be rich in protein, fiber, fat and ash but low in carbohydrate and energy compared to wheat flour. Three biscuit samples were prepared by supplementing wheat flour at the rate of 3%, 5% and 7% those were coded as F1, F2, and F3, respectively. Further, one control sample was prepared to compare quality of the proposed samples. Physical, physiochemical and sensory quality of the samples were evaluated. Spinach powder incorporation increased weight, diameter and density of the biscuits and decreased thickness, spread ratio and energy value compared to sample C. Lower values of moisture content 3.26%, 3.15% and 3.12% and fat content 14.67%, 14.57% and 14.74% were obtained in case of F1, F2 and F3 sample than sample C (moisture content 3.85% and fat 20.12%). Spinach powder enhanced protein, fiber, ash, and carbohydrate content (from 6.53%, 1.16%, 1.54%, and 66.72% up to 10.18%, 1.93%, 3.7% and 69.75% respectively) in F1, F2 and F3 samples. The biscuits were found to be rich in essential minerals like calcium, iron and phosphorus ranged from 123.67 to 261.49 mg/ 100g, 1.20 to 5.19 mg/ 100g and 61.46 to 112.87mg/ 100g respectively. Furthermore, ANOVA analysis showed significant differences in sensory attributes (color, flavor, texture, taste and overall acceptability) of the biscuits samples. The preference values for all the attributes are higher for control sample. Among the composite biscuit samples F1 (supplemented with 3% spinach powder) obtained higher scores for color, flavor, texture, taste and overall acceptability (7.2, 7.13, 7.0, 7.2 and 7.73 respectively). The current study revealed higher amount of nutrition in all the composite biscuits with suitable formulae and biscuit with 3% spinach powder (F1) was mostly preferred by the consumers.Item DEVELOPMENT AND PERFORMANCE EVALUATION OF A MULTISTORIED UNIVERSAL CABINET DRYER FOR DRYING OF HIGH MOISTURE VEGETABLES(HAJEE MOHAMMAD DANESH SCIENCE AND TECHNOLOGY UNIVERSITY, DINAJPUR., 2018-06) PLABON, MD. EMRUL AHSAN; Prof. Dr. Md. Sazzat Hossain SarkerDevelopment of appropriate drying technique and associated dryer are important issues for quality and stable dried vegetables. The present research was carried out to design and fabricate of a multi-storied universal cabinet dryer (MSUCD) suitable for drying of high moisture vegetables. Further, drying performance of the dryer was compared to other three conventional drying methods (sun, shade and existing cabinet) in yielding quality dried mallow (napa shakh) powder. Necessary adjustments were employed for ensuring uniform distribution of drying air flow and temperature in all trays of the drying chamber. The dryer was found to be quite satisfactory functioning for drying of 13 locally grown vegetables. Drying results revealed that shorter drying time (only 1.00 to 2.67 hr) required for drying of leafy vegetables from initial high moisture content of 93% to final moisture content of 3.78% (wb). However considerably longer drying time (6.33 to 17.67 hr) required for drying of tuber vegetables from 90.20% to 6.44% (wb) final moisture content. Lesser energy (0.87kWh/kg) required in drying of leafy vegetables whereas comparatively higher energy (5.05 kWh/kg) was found to be needed in drying of tuber vegetables by this dryer. Consequently, drying cost was lower in drying of leafy vegetables than tuber vegetables. Thermal efficiency was found to be 42.19% and 7.61% in drying leafy and tuber vegetables, respectively. The drying time required for drying of the mallow leaves were 6 hr, 48 hr, 4.25 hr and 1.33 hr for sun, shade, cabinet and MSUCD, respectively. The obtained results showed that drying methods have significant effects on functional, antioxidant and sensory characteristics of dried mallow powder. Results also revealed that significantly higher amount of bioactive compounds and their antioxidant activity were found to be retained in mallow powder dried by MSUCD compared to other drying methods. Therefore, this work suggests that the MSUCD is promising for drying of all high moisture vegetables. Moreover, this work also provided the way to design prototype as well as industrial scale multi-storied universal cabinet dryer for drying of high moisture vegetable products.Item CHILD NUTRITIONAL STATUS, FOOD AND NUTRIENT INTAKE PATTERN OF LANDLESS AND MARGINAL FARM HOUSEHOLDS OF CHEHELGAZI UNION IN DINAJPUR DISTRICT(HAJEE MOHAMMOD DANESH SCIENCE AND TECHNOLOGY UNIVERSITY, DINAJPUR, 2012-06) MAHMUD, MIR SABBIR AL; Prof. Dr. Mohammad Shiddiqur RahmanBalanced food intake is needed by individual human being for maintaining good health and nutritional status for active and prosperous life. Household food & nutrient intake pattern and child nutritional status for the landless and marginal farm households for rural are not well known. This study is therefore undertaken to know the socio-demographic and economic condition, food and nutrient intake pattern and child nutritional status of the landless and marginal farm families of rural areas. In this regard this study was carried out on 75 landless and marginal households having under five years children in family of Chehelgazi union in Dinajpur district. Survey method was employed for data collection. Information on dietary intake for past 24 hours recall and direct weighing method, anthropometric measurements and socio-economic indices were recorded. This study found that about 9% are working mother and 91% are housewife, 80% HHs have one earning member and 20% HHs have 2 & above earning members in family. The average monthly income and average monthly expenditure on food of the studied households are 6452Tk and 5046Tk respectively. About 65% HHs are poor families; this figure is much higher than the national percentage of poor families. The percentages of stunting, underweight and wasting children (6-59 months) are 29.4%, 28% and 4% respectively. Results revealed that boy children are more sufferers in stunting than girls children, while girl children are more sufferers in underweight than boy children. There is no significant difference found for stunting and underweight children according to landless and marginal farmer’s children. Mean total food intake is found 864.15 gm/day. Per capita per day total food intake is found 991.46gm, 872.14gm and 703.92gm respectively for the families of non-poor, absolute poor and hard core poor. The mean per capita per day energy intake by the landless and marginal families is found 2001.38 kcal. Per capita per day mean energy intake by landless households are lower (1989.9kcal) than for marginal households (2056.05kcal). Household heads education, mother’s education, monthly income of the household (Tk.) and monthly expenditure from food item has significant positive correlation with total food intake and nutrients intake. With the increases of parental education the protein and fat intake by the HHs increases but carbohydrate intake decreases. Positive relationship is found with economic status of the HHs with protein, fat, and calcium intake by the family members. The findings regarding low food and nutrient intake as well as poor nutritional status of children for the landless and marginal family obviously indicate their inability to lead a socially useful and economically productive life.Item DEVELOPMENT AND PERFORMANCE STUDY OF A CABINET DRYER(HAJEE MOHAMMOD DANESH SCIENCE AND TECHNOLOGY UNIVERSITY, DINAJPUR, 2012-06) ZUBAIR, MD. IMTEAJ; (Prof. Dr. Md. Kamal Uddin Sarker)Moisture content is an important factor in the preservation of grains. If the moisture content is above the safe moisture level at suitable temperature, the grains are in the risk to be attacked by different types of insects and microorganisms and loss of value due to spoilage. Due to the lacking of drying facilities, a huge amount of produced grains are lost every year in Bangladesh particularly in the rainy season. Keeping the problem in mind a cabinet dryer was developed in the Power and Machinery Laboratory, Faculty of Agro-Industrial and Food Process Engineering, Hajee Mohammad Danesh Science and Technology University, Dinajpur. The dimensions of the dryer are 1.52m long, 0.61m wide and 1.52m high. An automatic temperature control system was incorporated in the existing dryer by using thermocouple, temperature controller and magnetic contractor to control the quality of the grain. This system maintains the safe drying temperature level for grain. There are four trays placed one over other inside the dryer. The grain holding capacity of each tray is 10kg of fresh paddy. About 40kg paddy was dried per batch at the temperature 43-44°C in seven hours period from the initial moisture content of 25.2% to final moisture content of 13.6% (wb). The electricity cost for drying per kilogram of paddy was Taka 3.74.
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