Seaweeds – a potential source of food, feed and fertiliser

Many communities in the world consume naturally growing and cultivated/ farmed seaweeds as food. Currently, commercial cultivation/farming produces more than 96% of seaweeds in the world and only around 3-4% is obtained from wild harvest (noncultivated). Naturally occurring and cultivated seaweeds are categorized into green, brown and red seaweeds, based on their pigmentation. More than 200 species of seaweeds are of commercial value, but only around 10 species of seaweeds are popularly cultivated. China, Indonesia, the Republic of Korea and the Philippines are the leading producers of cultured/ farmed species (viz. Eucheuma, Japanese kelp, Gracilaria, Unndaria pinnatifid); and Chile, China and Norway for wild species (mainly brown and red) and Chilean kelp. Seaweeds are rich in dietary fiber (polysaccharides), essential amino acids, major and micronutrients (minerals), vitamins etc. It has been reported that some species are a good source of plant growth regulators. Mainly, the people in China, Japan and Korea relish the soups, stews, flakes, coatings, snacks, etc., made from seaweeds. The use of seaweeds as human food in India is not very common. The second major use of seaweeds after food is the extraction of three important hydrocolloids (Agar, Alginate and Carrageenan). These are used as food additives and in many other industrial applications. A small portion of seaweed is used as an ingredient as livestock feed and fish feed. Seaweed meal and liquid extract of seaweed have been tried in conjunction with inorganic fertilizers with beneficial effects on crop yield, quality produce and soil health. Seaweed is an important marine resource and the coastline in India can be utilized to commercially cultivate seaweed species beneficial for human health and plants. Research is required in developing functional foods, health foods and nutraceuticals from seaweeds to improve the health and nutritional status of the human population. This paper briefly describes the status of production and utilization of seaweeds in different parts of the world.

Performance evaluation of throat type updraft biomass gasifier using different biomass fuels

A biomass gasifier converts solid fuel such as wood waste, saw-dust briquettes and agro-residues into a gaseous fuel through a thermo-chemical process and the resultant gas can be used for thermal and power generation applications. The present research aims to evaluate the updraft biomass gasifier using different biomass for thermal application. The capacity of updraft gasifier was a 5-10 kg.h-1 and three types of biomass: maize cobs, sized wood and saw dust briquettes were used as fuel for producing producer gas by thermal application. The maximum carbon monoxide (CO), hydrogen (H2) and Methane (CH4) found were 14.8, 12.7 and 3.9%, 14.6, 13.7 and 3.9 % and 14.2, 13.5 and 3.9% at 5 kg.h-1 biomass consumption rate, respectively using maize cobs, sized wood and saw dust briquettes as fuel. The maximum and minimum producer gas calorific value was found 1120 and 1034 kcal.m-3; 1139 and 1034 kcal.m-3 and 1123 and 1036 kcal.m-3 at biomass consumption rate of 5 and 10 kg.h-1 using maize cobs, sized wood and saw dust briquettes as fuel respectively. The maximum gasifier efficiency of 77.94, 70.26 and 69.60% was found at the biomass consumption rate of 5 kg.h-1 using maize cobs, sized wood and saw dust briquettes as fuel, respectively. The minimum gasifier efficiency of 72.72, 64.49 and 64.90 % was found at the biomass consumption rate of 10 kg.h-1 using maize cobs, sized wood and saw dust briquettes as fuel in the system, respectively. The maximum overall thermal efficiency of 29.60, 30.65 and 23.69 % were found at the biomass consumption rates of 8, 7 and 7 kg.h-1 using maize cobs, sized wood and saw dust briquettes, respectively.

Physical and thermo-chemical characterization of agricultural residues and municipal waste

Characteristics of crop residues such as size, angle of repose, colour and density, calorific value, percentage of moisture content and chemical composition affect the production of bio-fuels. These properties also affect drying and handling of biomass and the design of thermal conversion systems. These characteristics can vary noticeably from waste to waste. In this study, four local varieties of rice straw (Nabina, Tamapasara, Swarnaand NuaAchharmati), sugarcane bagasse, coconut coir and vegetable waste were characterized. Study revealed that the sugarcane bagasse has the darker color, higher particle density (384.66 kg.m-3) compared to others tested biomass. Sugarcane bagasse contained highest percentage 82.7% of volatile matter followed by coconut coir, vegetable waste and rice straw. Rice straw variety Nabina has shown the highest calorific value 22.98 MJ/kg compared to Tamapasara, Swarna and NuaAchharmati and can be utilized for biofuel production.

Research requirement of agricultural engineering sector and formulation of new scheme at national level

Application of engineering in agriculture is getting momentum all over the world due to its long term benefit solution to the farming community besides attainment of sustainability in agriculture. Migration of people from agriculture to urban areas is inevitable due to socio economic changes. Application oriented agricultural engineering research is imperative for maximizing the input use efficiency, reducing post harvest losses, increasing the value addition of different agricultural produce, better utilization of agricultural waste for increasing the organic matter content of soil, promoting the utilization of solar energy in agriculture and thus increase the net income of the farmers. To retain the soil, water and youth in agriculture, agricultural engineering comprising of soil and water conservation, water management, farm machinery and power, post-harvest technology and value addition and agro energy activities in a dovetailed manner with a watershed approach shall be formulated at National level to retain the valuable soil and water resources besides encouraging youth to take up farming as a remunerative activity.

Optimization of the process of banana flour preparation

Banana (Musa paradisiaca) is a cheap source of carbohydrates and micronutrients. Converting banana into flour can help to obtain a consistent ingredient for bakery foods while preventing the post-production losses of this bulky and perishable food source. Hence a study has been undertaken to standardize the drying protocol for banana flour preparation. The effects of the different temperature-treatment combination on drying of banana were studied. Experiments were done at 50°C, 60°C and 70°C (without any treatment, with citric acid dipping and with combined citric acid and blanching process) and the variation in the quality of the dehydrated material was studied. The results showed that drying at 70°C followed by 0.5% citric acid treatment for 10 min, in 24h, in non-circulating natural convection air dryer was the optimal protocol concerning better quality parameters like water activity, total soluble solids, ascorbic acid, microbial contamination and the time taken to complete the drying process.

Performance of biomass combustor based drying system for ginger drying

A biomass combustor based dryer was evaluated with different biomass for drying of ginger. Biomass combustor based dryer consists of fuel hopper, combustion chamber, heat exchanger, grate for proper combustion of the combustible gas, chimney, ambient air inlet, hot air outlet and drying chamber. The system was evaluated at five fuel consumption rate (1 to 5 kg.h–1) and five air flow rate (100, 150, 200, 300 and 400 m3.h–1) using maize cobs, sized wood and saw dust briquettes for ginger drying. The experimental performances show that the hot air temperature inside the dryer vary between 36 to 81ºC for maize cobs, 53 to 85ºC for sized wood and 49 to 87ºC for biomass briquettes at tested air flow rate and fuel consumption rate in the system. The maximum efficiency of the system was found at the fuel consumption rate of 1 kg.h–1 and 400 m3.h–1 air flow rate using maize cobs, sized wood and saw dust briquettes as fuel respectively. The cost of operation of ginger drying at 1 kg.h–1 fuel consumption rate and 400 m3/h air flow rate was Rs. 32.76, 34.26, 34.76 and 55 per hour using maize cobs, sized wood, saw dust briquettes and mechanical drying system, respectively. Hence, the drying of ginger in biomass combustor based dryer using maize cobs at 1 kg.h–1 fuel consumption rate and 400 m3/h air flow rate resulted in better performance.

Studies on engineering properties of multiplier onion

The knowledge of physical and mechanical properties of onion bulb is important for successful design of any planter. Multiplier onion is propagated through bulbs and bulbs are planted manually. Manual planting of onion bulb is highly labour intensive (80-100 man-days ha-1) due to the close plant geometry (plant to plant and row to row spacing is 10 × 15 cm) among the vegetable crops. Engineering properties of multiplier onion were determined in order to design and develop a tractor operated raised bed onion bulb planter. In multiplier onion each onion comprises of 4-5 bulbs. These bulbs were cleaned, separated into single bulbs and divided in to 9 categories manually based on their individual weight viz., <2g, 2-3 g, 3-4 g, 4-5 g, 5-6 g, 6-7 g, 7-8 g, 8-9 g, >9 g. The onion bulb had a moisture content of 80.62±0.87 %. It was observed that the properties varied for different sizes of onion grades and the grades had highly significant effect on most of the properties. The linear dimensions of onion bulbs viz., length, width, thickness for nine grades ranged from 21.21±2.60 to 32.31±3.30 mm, 13.54±1.77 to 30.95±2.91 mm and 10.91±1.40 to 22.63±2.15 mm. The geometric mean diameter, sphericity, shape index and projected area all ranged from 28.22±2.04 to 14.54±0.96 mm, 0.87±0.06 to 0.69±0.08, 1.78±0.32 to 1.22±0.14 and 5.50±0.51 to 1.55±0.30 cm2, respectively. The one hundred onion bulb weight, bulk density, true density were in the range of 1185±19.59 to 121.6±6.30 g, 793.20± 9.45 to 480.19±13.13 kg.m-3, 1086± 205.22 to 1013.6±348.85 kg.m-3, respectively. The angle of repose decreased with increase in size of onion bulbs. The interaction between sphericity, shape index and angle of repose indicated that as the size of the onion size increase angle of repose decreased.

Effect of parboiling on cooking characteristics of finger millet and foxtail millet

Experiments on parboiling of finger millet (Eleusine coracana) and foxtail millet (Setaria italica) were conducted by soaking at 30, 40, 50, 60 and 70°C and steaming for 10, 15, 20, 25 and 30 min. The parboiled millet grains were shade dried and pearled in a laboratory scale pearler-polisher. The cooking characteristics of these parboiled millet grains were assessed in terms of cooking time, water uptake, swelling index and expansion ratio. In the case of finger millet, the cooking time, water uptake, swelling index and expansion ratio ranged 8-13 min, 1.6-3.7 g/g, 0.98-2.27 and 1.26-1.69, respectively. For foxtail millet these quality parameters ranged 9-13 min, 2.5-4 g/g, 1.32-2.75 and 1.45-2.4, respectively. Soaking at 70 and 60°C and steaming for 20 and 10 min, respectively for finger millet and foxtail millet resulted in better cooking characteristics, viz., water uptake, swelling index and expansion ratio, and lower cooking time.

Development of microcontroller-based data logger for real-time monitoring of drying and storage of food grains

Food grains are harvested at higher moisture content to avoid losses during harvesting. Temperature and relative humidity are the key control factors of drying and storage operations for maintaining and enhancing the quality of food. Real-time monitoring and management of these parameters improve the level of post-harvest processing and reduce losses. An effort has been made to develop a data logger for real-time monitoring of the drying and storage environment. It consists of different modules such as precision integrated temperature and relative humidity sensor DHT22, LCD, SD Card, motor control driver, and RTC 3231 for real-time monitoring and data recording of temperature and humidity. An open-source-based software program was developed to integrate all modules in one platform to operate sequentially. Developed data logger tested in a 0.5-tonne grain storage structure and 100 kg capacity solar-powered air-inflated dryer. The temperature of drying air ranged between 29.8 and 38.2°C compared to ambient air temperature ranging from 25.7 and 34°C. Moisture reduction from 22% to 14% (w.b.) was completed in 7.5-9 hours in the developed dryer compared to 11-12.8 hours in sun drying. Variation of temperature and humidity inside double-wall insulated silo is less as compared to the single wall and triple-layer plastic storage structure. The salient features of this developed system are costefficient, portable, robust, and fast use and perform satisfactorily under different conditions.

Performance evaluation of single row tractor operated carrot digger

Harvesting is one of the most critical operation in carrot cultivation because it is labour intensive (350 – 450 man-h/ha) and time consuming for the farmers. The present study was undertaken to evaluate the performance of single row tractor operated carrot digger designed by department of Farm Machinery and Power Engineering, COAE&T, CCS Haryana Agricultural University, Hisar, Haryana, India. The developed digger consisted of a digging, conveying, de-topping, collector and power transmission units. The carrot digger can be operated with 35 horse power tractor. It was evaluated under three variables viz., three digging blade angles (15°, 18°, 21°), three conveyor angles (25°, 35°, 45°) and three shoot catch heights (2, 4, 6 cm). The optimum value of variables obtained for operation of carrot digger were blade angle of 21°, conveyor angle of 250 and shoot catch height of 2 cm. Effective field capacity of the digger was 0.11 ha h-1 with field efficiency of 61.70 %. The digging efficiency, cut carrots, bruised carrots, picking efficiency and cutting efficiency of de-topping unit were 100, 0.62, 0.90, 62.29 and 100%, respectively at optimized value of operational variables. The labour requirement with developed carrot digger and manual method of harvesting was found 27 and 450 man-h ha-1, respectively. The operational cost of carrot digger was found Rs. 8242 ha-1 and it saves time and cost of operation in comparison to manual method of carrot harvesting. The break-even point, payback period and benefit cost ratio were 234 hours, 2.21 years and 1.56, respectively when operated for 400 hours annually. The carrot digger works better if carrots are sown in single row on the ridges rather than the broadcasting method.