Poritosh Roy Doctoral Program in Environmental Engineering, School of Enginering, University of Guelph, Guelph, ON, N1G 2W1, Canada
Research Interests: Food Processing, Packaging, Distribution and Quality, Food Security, Dietary choice and health, Life Cycle Assessment (LCA) of Agricultural Products, Cost analysis, Energy in Agriculture, Agricultural Waste Management, Energy and Environment
Education: 2004 PhD in Agricultural Sciences, University of Tsukuba, Tsukuba, Japan.
1996 M. Eng. in Agricultural Engineering (Agricultural Machinery), Asian Institute of Technology, Pathumthani, Thailand.
1992 B. Eng. in Agricultural Engineering (Farm Power and Machinery) Bangladesh Agricultural University, Mymensingh, Bangladesh.
Work History: April 2008–August 2011. Post-doctoral Researcher, Distribution Engineering Laboratory, National Food Research Institute, Tsukuba, Japan.
April 2006–March 2008. JSPS Fellow (Post-doctoral), Distribution Engineering Laboratory, National Food Research Institute, Tsukuba, Japan.
May 2004–March 2006. Post-doctoral Researcher, Distribution Engineering Laboratory, National Food Research Institute, Tsukuba, Japan.
Jan 1998–August 1998. Graduate Assistant, Faculty of Engineering, University Putra, Malaysia, Serdang, Malaysia.
April 1997–September 1997. Research Associate, Energy Program, Asian Institute of Technology, Pathumthani 12120, Thailand.
Sep 1996–March 1997. Research Associate, AFE Program, Asian Institute of Technology, Pathumthani 12120, Thailand.
November 1992–Nov 1994. Researcher, Farming System and Environmental Studies, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh.
Abstract: Liquid biofuels are widely recognized alternatives to fossil fuel not only to combat the global warming potential, but also to reduce the reliance on fossil fuels for smooth economic development. The production and the use of lignocellulosic liquid biofuel have been emphasized because it is highly reproducible and does not compete with food. This study summarized the LCA studies on lignocellulosic ethanol produced from various biomass resources focusing on energy balance, greenhouse gas (GHG) emission and other impact categories, and production cost to discuss their potential environment and socioeconomic impacts. Numerous efforts have been made to evaluate the life cycle of lignocellulosic ethanol with LCA methodologies and deals with feedstock, energy paths, conversion technologies, allocation methods, utilization of by products etc. to determine the environmental impacts as well as the production cost. The environmental benefits are reported in most of the studies except for few examples. A wide variation was observed in the reported production cost of ethanol which is dependent on the feedstock, conversion technologies, allocation methods and plant sizes. Onsite enzymes production/buying appeared to be the main hotspot, demands a vigorous study to improve their productivity and to reduce the cost. Another promising alternative for compensating production costs are seem to be the generation of valuable coproducts and integration of ethanol production processes (ethanol and energy). The reviewed literatures indicate that despite the environmental benefits of ethanol produces from lignocellulosic biomass, the economic viability is doubtful at present, even highly optimistic assumptions are made for the cost calculation, especially in the case of enzyme. Hence, the biotechnological revolution is must for the sustainability of bioethanol, especially the in the field of enzymes and microorganisms, and adaptation of innovative technologies and renewable energy policy may lead to curtail the cost, however careful consideration have to be placed on the land use changes and soil quality to avoid any productivity loss.
Abstract: The food industry is one of the worldâs largest industrial sectors, hence a large contributor of greenhouse gases (GHG) which cause global warming. This study evaluates the life cycle of various types of meat to determine if the GHG emission from the meat industry in Japan could be reduced if the population makes different dietary choices. It was confirmed that the GHG emission of beef was greater than that of pork or chicken. The GHG emission from meat in general also depends on the per capita caloric intake (if meat supplies the recommended animal protein or contributes to it at the present rate). In a healthy and balanced diet (9.2 MJ i.e., 2,200 kcal in total, where either mixed meat or chicken or pork or beef contributes 2.2%), the GHG emission is estimated to be 0.28 or 0.17 or 0.15 or 0.77 kg CO2 eq/person/day, respectively. A change in consumption patterns (from beef to chicken or pork) and the adoption of a healthy and balanced diet would help to abate about 2.5â54.0 million tons (CO2 eq) produced by the meat industry each year in Japan.
Abstract: Rice is the staple food for nearly two-thirds of the worldâs population. Food components and environmental load of rice depends on the rice form that is resulted by different processing conditions. Brown rice (BR), germinated brown rice (GBR) and partially-milled rice (PMR) contains more health beneficial food components compared to the well milled rice (WMR). Although the arsenic concentration in cooked rice depends on the cooking methods, parboiled rice (PBR) seems to be relatively prone to arsenic contamination compared to that of untreated rice, if contaminated water is used for parboiling and cooking. A change in consumption patterns from PBR to untreated rice (non-parboiled), and WMR to PMR or BR may conserve about 43â54 million tons of rice and reduce the risk from arsenic contamination in the arsenic prone area. This study also reveals that a change in rice consumption patterns not only supply more food components but also reduces environmental loads. A switch in production and consumption patterns would improve food security where food grains are scarce, and provide more health beneficial food components, may prevent some diseases and ease the burden on the Earth. However, motivation and awareness of the environment and health, and even a nominal incentive may require for a method switching which may help in building a sustainable society.
Abstract: The cooking process was studied with an automatic rice cooker to determine the cooking
properties of different forms of rice (well milled rice: WMR; partially-milled rice: PMR;
germinated brown rice: GBR; brown rice: BR). Each form of rice was cooked with three
different water-rice ratios using recommended cooking modes and temperature and energy
consumption profiles were measured. Physical properties of cooked rice were also measured.
Cooking time, temperature and energy consumption profiles differed among rice forms and
consumed different amounts of energy. For a certain hardness value of cooked rice, brown rice
required the longest cooking time and highest water-rice ratio and attained the highest amount of
moisture and consumed the highest amount of energy compared to the other forms of rice. This
study revealed that the cooking properties of rice are dependent upon the form, the water-rice
ratio and the preset cooking mode.
Abstract: The CO2 emission of fresh produce distribution via the wholesale market was analyzed. In order to examine its environmental impacts, differences in vehicle size and distribution mode were considered. The posibility of reduction of the environmental impact by the wholesale distribution system for fresh produce was discussed based on the CO2 emission. Options for reduction of CO2 emission in the distribution via the wholesale market were proposed: enlargement of the transport vehicles, introduction of modal shift, and the division/forwarding of loads. It was shown that distribution via the wholesale market was effective in reduction of greenhouse gas emission than was the sectored distribution system.
Abstract: Changes in the quality of sweet potato during hot air drying, such as L-ascorbic acid, sugar content, surface color and hardness, and drying characteristics, were investigated at temperatures of 30, 40, 50, and 60°C. Equilibrium moisture contents (EMC) of sweet potato samples in the desorption process were measured by a static method at the four aforementioned temperatures and six selected relative humidity levels. Using both the measured moisture content data in the drying test and the EMC values, hot air drying characteristics of sweet potato was estimated. Changes in L-ascorbic acid content of sweet potato during hot air drying was measured, wherein a first-order reaction rate equation was applied to model the change in decomposition of L-ascorbic acid content. In addition, surface color, sugar content, and surface hardness were also measured. The total color change (ÎE) of the samples was observed to decrease as drying temperature was increased. The effects of sample sugar concentration on surface hardening during hot air drying of sweet potato are discussed.
Abstract: This paper characterizes the physico-chemical properties of the soybean oil-based polymeric surfactant, Palozengs R-004 (hereafter referred to as R-004). The surface activity of R-004 is comparable to the reported activities of biosurfactants produced by microorganisms and higher than some of the conventional synthetic surfactants. The surface tension of Milli-Q water was reduced to a minimum value of roughly 30 mN/m at a concentration of about 0.07 wt.%. R-004 exhibited a unique aggregation behavior: small aggregates (pre-micelles) were formed at very low concentrations. Zeta-potential measurements showed that the micelles of R-004 are negatively charged due to the presence of carboxylic groups. The ability of R-004 to form and stabilize microbubbles was evaluated and was found to be greatly affected by filtration while remaining independent of R-004 concentration over the concentration range studied (0.05â0.5 wt.%). These results suggest that a very low level of surfactant can be used to produce microbubbles without affecting their properties. Our results suggest the possibility of using soybean oil-based surfactants to food, pharmaceutical, and cosmetic applications.
Abstract: Rice is the most important agricultural commodity in Japan. It is consumed in various forms, each of
which uses different amounts of resources and energy. This study attempts to evaluate the life cycle of
rice (well- and partially-milled, brown, and germinated brown rice) and compare it to the parboiled
milled rice to determine if the environmental load from the life cycle of rice can be reduced. The life cycle
inventory (CO2 emission) increases gradually from partially-milled (milling 2%) to the parboiled rice. The
paper-bag option seems to be more environmentally friendly than the polyethylene-bag option. It is
worthwhile to note that the partially-milled rice not only reduces the environmental load but also retains
more food nutrients compared to the well-milled rice. A change in rice production and consumption patterns
would be helpful to reduce about 2â16% of the negative environmental impact coming from the
current life cycle of rice in Japan.
Abstract: Life cycle assessment (LCA) is a tool that can be used to evaluate the environmental load of a product, process, or activity throughout its life cycle. Todayâs LCA users are a mixture of individuals with skills in different disciplines who want to evaluate their products, processes, or activities in a life cycle context. This study attempts to present some of the LCA studies on agricultural and industrial food products, recent advances in LCA and their application on food products. The reviewed literatures indicate that agricultural production is the hotspot in the life cycle of food products and LCA can assist to identify more sustainable options. Due to the recent development of LCA methodologies and dissemination programs by international and local bodies, use of LCA is rapidly increasing in agricultural and industrial food products. A network of information sharing and exchange of experience has expedited the LCA development process. The literatures also suggest that LCA coupled with other approaches provides much more reliable and comprehensive information to environmentally conscious policy makers, producers, and consumers in selecting sustainable products and production processes. Although LCA methodologies have been improved, further international standardization would broaden its practical applications, improve the food security and reduce human health risk.
Abstract: Bamboo shoots (Phyllostachys pubescens Mazel) harvested from two cultivation areas were used to investigate the amount of accumulated sugars (sucrose, glucose, and fructose) in four sections along the length of a bamboo shoot. Bamboo shoots harvested from above ground (emerged bamboo shoot) and underground of the same cultivation area were also used to study the changes in sugar content during storage at both 5 and 25 °C. The amounts of sucrose, glucose, fructose, and total sugar of underground bamboo shoots were higher than those of emerged shoots. Sucrose content in the apical section was significantly higher than that in other sections. Meanwhile, higher amounts of glucose, fructose, and total sugar (the sum of sucrose, glucose, and fructose) were observed in the basal section. Changes in sugar content were also observed during storage. The fresh, unpeeled bamboo shoots have particular cellular chemical properties and respond differently to storage duration and condition depending on harvest maturity.
Abstract: Ethylene production and the accumulation ofthe l-aminocyclopropane-l-carboxylic acid synthase (ACS; EC 4.4.1.14) gene were determined in tomato (Solanum lycopersicum L.) fruit that were dropped from a height of 5 em. Dropped fruit had higher ethylene production than nondropped controls, and this lasted for at least 10 h. Maximum accumulation of Le-ACS2, one of the members of the Le-ACS multi gene family, was achieved 5 h after dropping, and changes in accumulation tracked closely with ethylene production. In comparison with control fruit, substantial accumulation of Le-ACSIA, Le-ACS4, or Le-ACS6 in dropped fruit was not observed. These results indicated that the increased ethylene production following fruit dropping was most likely regulated by Le-ACS2 transcripts. The transfer of dropping stimuli from directly stressed tissues was investigated by measuring Le-ACS2 accumulation at various positions on the dropped fruit. Le-ACS2 was mainly induced in the fruit pericarp, and there was low accumulation in the fruit interior. The Le-ACS2 accumulation linearly decreased with increasing distance along the pericarp from the stressed site. This implied that accumulation of Le-A CS2 was dependent on stress levels, while most ethylene that was derived from dropping was produced at the stressed site. Using levels of Le-ACS2 accumulation, the ethylene production of tomato fruit at mechanically impacted sites was estimated to be about 50 times higher than that of nondropped controls.
Abstract: Microwave drying characteristics and physical properties,
such as hardness, volume, surface area and color,
of a sliced radish were investigated at moisture contents
ranging from . to . (d.b. decimal). These drying characteristics
and physical properties were then compared
with those of hot air and vacuum drying. For microwave
they were decreased for hot air and vacuum drying processes.
Using surface area measurements taken after each
of the three drying methods, drying characteristics involving
shrinkage (or expansion) were compared. These
findings show that the microwave, hot air and vacuum
drying processes are in the first falling rate period from
. to . (d.b. decimal). Changes in the moisture content
of the samples were analyzed by the exponential model,
which agreed well with the empirical moisture content
changes. The drying-rate constants of radish during microwave,
hot air and vacuum drying were estimated to be
. . and . s , respectively. In
addition, color deterioration of radish could be prevented
using microwave drying.
Abstract: The freezing process was studied at â5 °C to determine the physicochemical properties and the freezing point temperature (FPT) of chestnuts. The cooling curve method was used to measure the FPT. A multiple linear regression model was also developed to predict the FPT. The FPT was found to be dependent on the sugar content. It seems that the FPT is also influenced by the mass of the chestnut. For a certain chestnut (mass 13.95 g, sugar content 5.14%), the FPT was observed to be â1.7 °C. A high correlation was found between the freezing point predicted by the model and the measured one. Hence, the developed model might be used to predict the FPT of chestnuts for efficient and effective storage.
Abstract: Life cycle of fresh tomato was evaluated to determine CO2 emissions during its cultivation and distribution. Low temperature (LT) and modified-atmosphere packaging (MAP) were compared for their effect on quality. Road and sea transport were also compared. The method of cultivation and transport and the distribution systems affected the overall life cycle inventory (LCI, CO2 emissions). Life cycle inventory was larger for greenhouse produce than for that raised under plastic cover and larger for produce transported by road than for that transported by sea. The distance between production and consumption area affected the LCI significantly. It is worthwhile to note that MAP would not be environmentally acceptable over LT packaging in the case of tomatoes transported by road over a distance shorter than 2000 km although such transport does not require any cooling during transport and storage: MAP would be a better option in the case of sea transport beyond 1000 km. The distance over which MAP is the better option is thus dependent on the mode of transport because the two modes of transport differ in speed and, therefore, in emissions. A change in cultivation from greenhouse to plastic cover, in transport from road to sea, and in packaging from LT to MAP is required to minimize the LCI and would abate approximately 0.14â0.24 million tonnes of CO2 emissions a year from Japan.
Abstract: Vibrations are usually analysed by the fast Fourier transform (FFT) algorithm, and
this method is effi cient for analysing frequency characteristics of vibrations during
transportation. However, the nature of vibrations during transportation is nonstationary,
and the FFT method is not suffi cient for dealing with such a nonstationary,
time-dependent data in some cases. In this study, vibration data were
analysed for non-stationary events using a wavelet algorithm. Although apparent
changes in frequency characteristics of vibrations were not observed, a continuous
wavelet transform suffi ciently detected the time dependence of frequency
characteristics. When strong shocks were contained in vibration data, wavelet
power spectra were signifi cantly increased corresponding to shocks, and the
changes were over a wide range of frequencies. The analysis using discrete wavelet
transform indicated that shock signals were located in several decomposition
levels, and this was dependent on shock direction. Locally amplifi ed detail
coeffi cients and a subsequent reconstruction successfully generated shock-added
vibration data, considering the frequency characteristics of actual shocks. This
procedure is expected to be used as a shock generation method in vibration tests.
Abstract: The effects of processing conditions on the energy consumption and quality of short- and long-grain rice were studied. The energy consumed during milling increased and the head rice yield decreased with an increase in the degree of milling (DOM). The energy consumed during the cooking and the moisture content of cooked rice was found to be dependent on the DOM and the variety of rice. The overall energy consumption was found to be greater for brown rice than for well- and partially milled rice, but there was no significant difference between the partially and well-milled rice. However, some of the nutrients that are beneficial to health were found to be lower in well-milled rice than in partially milled and brown rice. A lower DOM (Koshihikari) not only conserves energy in the life cycle of rice and improves head rice yield, but also retains more of the nutrients.
Abstract: Life cycle of rice (produced by vessel, medium-boiler and untreated process) was evaluated to determine environmental load and production cost of rice in Bangladesh. All the production processes have a negative effect on the environment and the environmental load varies from process to process. The inventory results (energy consumption and CO2 emission) gradually decreased from the vessel to the untreated process (vessel > medium-boiler > untreated). The untreated process was found to be both the environmentally sustainable and cost effective process compared to the others, if milled rice is consumed instead of head rice (whole kernels after milling). A change in production process and consumption pattern (parboiled to untreated rice) would help to conserve 8â29% primary energy (biomass) and abate 2.5â9.6 million tons CO2 emission per year in Bangladesh.
Abstract: This study was conducted at Gazole in the Malda district of West Bengal, India, by both the physical monitoring and questionnaire survey to evaluate the local parboiling processes (vessel, small-boiler and medium-boiler). The biomass consumption and head rice yield were measured and the market values were assessed by a questionnaire. The net present worth (NPW), payback period and internal rate of return were also determined. The parboiled rice produced under boiler processes had a higher market value (US$157.4/t) compared to the vessel (US$151.6/t), but required a greater initial investment. The boiler processes were reported to be less tedious and provided a better working environment compared to the vessel. The head rice yield was estimated to be 65.9%, 69.2% and 66.6% for the vessel, small-boiler and medium-boiler process, respectively. The medium-boiler consumed the lowest amount of energy (1659 MJ/t) compared to the others. The cost analysis of the parboiling processes revealed that all the processes are economically viable, but the small-boiler was found to be the most attractive, having the shortest payback period and the highest internal rate of return. The local parboiling process can be improved in terms of the energy consumption and the market value of the rice by adopting the medium-boiler process.
Abstract: Rice processing is one of the most important agro-industry. It consumes a considerable amount of
energy and is responsible for environmental pollution. Life cycle inventory analysis has been
performed on rice (parboiled and fresh) produced by different production processes (vessel, smallboiler,
medium-boiler and untreated) to find an environmentally-friendly rice production process.
The inventory results (energy consumption, atmospheric emission and solid waste) gradually
decreased from the small-boiler to the untreated process (small-boiler ) vessel ) medium-boiler )
untreated) and there is no waterborne emission in the case of the untreated process. The untreated
process was found to be more environmentally-friendly compared to the others, however due to the
lowest head rice yield (whole kernels after milling), it consumes greater resources (paddy). Among
the parboiling processes the medium-boiler was found to be better, which has a lower energy
inventory, atmospheric emission and solid waste compared to the others. This study also reveals that
fuel switching only for cooking (biomass to electricity ; electricity was assumed to be generated from
biomass by IGCC technology) conserved primary energy (biomass) and reduced atmospheric emission
(CO2, CO, CH4, TSP, NOx, and SO-) significantly.
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Abstract: Rice is the staple food for nearly two-thirds of the worldâs population. Although the total production has significantly increased, per capita production remains almost unchanged i.e., ever increasing population growth offsets the hard won productivity. A lot of efforts have been made to keep the rice harvest in step with population growth affects all aspects of the soil, water, land, biodiversity and the services provided by an intact ecosystem. Rice properties are found to be dependent on the methods of cultivation, location, variety of rice and processing conditions. Genetically modified (GM) rice serve various purposes, such as increasing the yield, improving nutritional and /or health characteristics and reducing the agricultural inputs. However, demerits of GM crops are also reported, which limits their acceptance as food. Brown rice (BR), germinated brown rice (GBR) and partially-milled rice (PMR) contains more health beneficial food components compared to the well milled rice (WMR). BR and GBR contains more phenolic compounds and consumption of these nutrients accelerate the metabolism of brain help prevent some diseases such as gastrointestinal cancers, heart disease, high blood pressure, diabetic and beriberi, constipation, and Alzheimerâs diseases, and also enhances maternal mental health and immunity during lactation. A change in consumption patterns from parboiled rice to untreated rice, and WMR (degree of milling: DOM 10%) to PMR (DOM 2%) may conserve about 54 million tons of rice. Life cycle inventory (LCI) analysis on rice reveals that environmental load of parboiled rice is greater than that of untreated rice. LCI analysis also depicts that PMR (DOM 2%) not only contains more food components and reduces environmental loads but also reduce food insecurity where food grains are scarce. A switch in production and consumption patterns would improve food security where food grains are scarce, and also provides more health beneficial food components and reduces pressure on land, water and the natural resources. However, motivation and awareness of the environment and health, and even a nominal incentive are required for a method switching which may help in building a sustainable society.
Abstract: Greenhouse gas emission, which has increased remarkably due to tremendous energy use, has resulted in global warming, perhaps the most serious problem that humankind faces today. Numerous efforts have been made to mitigate the greenhouse gas emission from human activities. This study reveals that the global environment is influenced by bioenergy, cropping patterns, dietary choices, packaging, distribution and trade, and population growth might be the main key. The use of bioenergy has been emphasized not only to combat the global warming potential but also to reduce dependency on fossil fuels for smooth economic development. The rush toward liquid biofuels affects virtually every aspect of the field crop sectors, ranging from domestic demand and exports to price and the allocation of land area among crops. Crop residues should not be harvested for biofuels beyond the limits that reduce minimum soil organic carbon to maintain soil fertility and productivity, with the exception of a satisfactory supply of compost. The development and introduction of sustainable energy technology must occur in an affordable and socially acceptable manner. Production of genetically modified (GM) crops might be useful in reducing growing pressure on natural resources and on the environment, if that does not conflict with safety and biodiversity. The combination of population growth with economic development and increasing demand for quality food, especially in the developing countries, puts great stress on agriculture for food, feed, fibers and biofuel feedstocks. If the population can be stabilized to a 1990-level and food spoilage and other waste limited to 10%, then about 52% of the world food supply could be conserved. It might open the door for future liquid biofuels and help to reduce poverty and to build a sustainable world.
Abstract: Parboiled rice is the staple food in Bangladesh. It has been produced by both traditional and modern methods. Modern methods are energy and capital intensive, and are not suitable for small-scale operation at the village level. Various methods and devices are being used in the traditional parboiling process. The device consists of pottery to boilers. Among the devices the vessel is the most commonly used traditional parboiling device at villages. Laboratory-scale studies were conducted under open and covered conditions using an automatic electric rice cooker to determine if the traditional parboiling process (vessel) can be improved in terms of energy consumption and rice quality. Local parboiling processes were also evaluated to find a cost and energy effective parboiling process. Finally, to determine the energy consumption in the life cycle of rice, dehusking, milling and cooking processes were also studied.
Firstly, parboiling treatment was given to the paddy in a rice cooker vessel, where 20% of paddy was submerged in the water during pre-steaming and steaming. Submerged paddy was parboiled by the hot water and the rest was parboiled by steam generated in the system. The energy consumption in parboiling, qualities of parboiled rice and the material temperature during pre-steaming and steaming were measured. Faster rise of material temperature during pre-steaming and steaming were observed under the covered method. There is no difference in overall quality indices between two methods. The hardness of parboiled brown rice was higher for the bottom layer than the surface layer and the covered method provided higher value with even less amount of energy being consumed compared to the open method.
After the first step, the studies were conducted to investigate the effect of temperature distribution in the traditional parboiling process. A sample holder with a wire-mesh bottom was used to keep back the sample from the hot water. The material temperature and the qualities of parboiled rice (hardness, color, lightness and head rice yield) were determined for different layers. The energy consumption was also measured. The temperature distribution in the traditional parboiling process was found to be uneven. However, the covered method has a propensity to improve the temperature distribution. A faster rise of material temperature was observed for the first layer compared to the other layers. The hardness, color intensity and head rice yield were found to be the highest for the first, next was the second and the last was the third layer. On the other hand, the lightness value was the lowest for the first, next was the second and last was the third layer. The hardness, color intensity, lightness value, material temperature and the energy consumption were about 70 N, 24, 60, 90ï°C and 1150 to 1290 MJ/t, respectively, corresponding to the maximum head rice yield (67-68%, first layer) which are considered to be suitable quality of parboiled rice. The covered method was found to be liable to improve material temperature, qualities of parboiled rice and heat utilization efficiency. The laboratory scale studies reveal that covered method of parboiling can be adopted to improve the traditional parboiling process.
Local parboiling processes (vessel, small boiler, medium boiler) were evaluated at Gazole under the Malda district in West Bengal, India. The energy consumption and the qualities of the parboiled rice produced in the vessel, small boiler and medium boiler process were measured. The net present worth (NPW), payback period, internal rate of return, production cost and profit were also worked out and compared with the fresh rice. Little difference in hardness value was observed among the processes. The color and lightness values were found to be the same in all processes. The parboiled rice produced under small and medium boiler methods had higher customer acceptance and market value compared to the vessel process but required higher initial installation cost. The small and medium boiler processes were found to be less tedious and provide better working environment compared to the vessel process. Among the parboiling processes, the medium boiler consumed the lowest amount of energy (1659 MJ/t). The cost analysis of the rice production processes revealed that all the processes are economically viable, but the small boiler was found to be most attractive, having the shortest payback period and the highest internal rate of return. The experimental results reveal that the local parboiling process can be improved in terms of energy consumption and market value of parboiled rice by adopting the medium-boiler process.
Energy consumption in dehusking and milling process was measured with a rubber roll dehusker and a friction type-milling machine, respectively. Energy consumption in the dehusking process was found to be greater for fresh paddy compared to the parboiled paddy. On the other hand, parboiled rice consumed greater energy in the milling process compared to the fresh rice to get the same degree of milling. The overall energy consumption in dehusking and milling process was observed to be greater in the case of parboiled rice compared to the fresh rice.
Cooking process was studied under soaking and without soaking conditions with an automatic electric rice cooker to determine if the cooking energy can be conserved. The rice was cooked under 0, 30 and 60 min of soaking with different amounts of water (water-rice ratio: 1.5, 2.0 and 2.5) and the moisture content and hardness of cooked rice were measured. The hydration characteristic of rice was also measured at different soaking intervals (0, 30 and 60 min). The hydration of rice was increased with an increase in soaking time and it was higher for parboiled rice compared to the raw rice. The moisture content and the hardness of cooked rice were found to be 66 to 69% and 8 to 10 N (for single kernel), respectively, which consumes 3.6 to 4.2 MJ/kg of energy under different soaking time before cooking and with a water-rice ratio of 2.5. The parboiled rice required a longer cooking time and consumed a greater amount of energy compared to the raw rice. The energy consumption was reduced with an increase in soaking time for all types of rice. This study reveals that the cooking energy can be conserved by adopting the presoaking process, which would be helpful in reducing the environmental pollution.
Finally, life cycle inventory analysis has been performed on rice (parboiled and fresh) produced by different production processes (vessel, small boiler, medium-boiler and untreated) to find an environmentally friendly rice production process. The inventory includes energy consumption, atmospheric emission, waterborne emission and solid waste. This study reveals that all the processes are responsible for environmental pollution, but the intensity of pollution varies from the process to process. The inventory results (energy consumption, atmospheric emission and solid waste) decrease gradually from small-boiler to untreated process (small-boiler>vessel>medium-boiler>untreated) and there is no waterborne emission in the case of untreated process. Among the processes studied, the untreated process was found to be the environmentally friendly compared to the others, however due to the lowest head rice yield it consumes greater resource (paddy). Among the parboiling processes the medium-boiler was found to be the better option, which has lower energy inventory, atmospheric emission and solid waste compared to others. This study also reveals that the fuel switching only for cooking (biomass to electricity) conserved about 22 to 29% primary energy (biomass) and reduced about 24 to 30% atmospheric emission (CO2, CO, CH4, TSP, NOx, and SOx).
Considering the scarcity of food grains and resource consumption it would be wise to produce parboiled rice by adopting the medium-boiler process even though it consumes greater energy than the fresh rice. Energy conservation would lead to reduce the tediousness of fuel-wood collection, improves home environment and reduce health risk. A nominal incentive to install boiler process, and motivation and awareness of environment and health are required for method switching. The method switching would be helpful to reduce the environmental pollution, deforestation and global warming.
Abstract: Pineapple plants, after the first harvesting, need to be dressed for good ratoon crop growth and for the healthy shoots for next planting. So far, pineapple plant dressing is done manually which is a very time consuming and back breaking job. To overcome this, a low cost pineapple plant dressing machine was developed. The developed machine was mounted at the front of the power tiller with an engine capacity of 8.6 kW. A special transmission mechanism was developed to transmit power from the engine to the rotary blades. At a time, the machine could dress two rows of pineapple plants. The rotational speed of the cutting blade was 533 to 800 rpm. The field tests were conducted at 1.21 to 1.74 km/hr forward speed. Some of the physical properties of a pineapple plant stem and leaves were investigated.
The preliminary testing of the machine was carried out in a field with tall and strong grass. Based on the working problems of the first prototype the machine was modified. The second prototype was tested at the pineapple plantation site. The field testing showed that the developed machine could dress an area of 0.11 to 0.15 ha/hr. The average field efficiency and cutting efficiency were found to be 73.28 and 90.1% respectively. The machine with the power tiller was capable of dressing over six to eight times the area covered manually. The estimated cost of dressing with the developed machine was $12.20/ha which is one-third of the cost of the traditional method. The performance and cost analysis of the machine indicates that considering the current labor shortage, the machine will have wider application for pineapple growers.
