Moisture Dependent Physical Properties of Dill R.K
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R.K. Singh, R.K. Vishwakarma, M.K. Vishal, Deepika Goswami and R.S. Mehta JAE : 53 (1) Journal of Agricultural Engineering Vol. 53 (1): January-March, 2016 Moisture Dependent Physical Properties of Dill R.K. Singh1*, R.K. Vishwakarma2, M.K. Vishal1, Deepika Goswami2 and R.S. Mehta1 Manuscript received: September, 2014 Revised manuscript accepted: November, 2015 ABSTRACT Physical properties of dill (Anethum sowa Roxb) seeds were investigated as a function of moisture contents in the range of 4.85% to 24.81% (d.b.). Seed geometric parameters such as average length, width, thickness, geometric mean diameter, volume and seed surface area increased with increase in seed moisture; whereas sphericity remained unchanged. The 1000-seed mass increased linearly with increase in moisture. Bulk density and true density of dill seeds decreased with increase in seed moisture content from 4.85 to 24.81% (d.b). Porosity of seeds showed a decreasing trend with the increase in moisture content. The angle of repose, coefficients of static friction against different surfaces (plywood, mild steel, galvanized iron and glass) and terminal velocity increased with seed moisture. Key words: Dill (Anethum sowa Roxb), physical properties, frictional properties, seed spices Anethum sowa L. (known as Dill or Sowa) belongs to the soap perfume and finds applications in food industry for family Apiaceae, and is one of the four species of genus flavouring and seasoning purposes. Anethum that yields dill oil. It is grown in the tropical and sub-tropical parts of India and tropical regions of Asia For efficient processing operations, it is essential to have (Anon., 1948; Chevallier, 1996). In India, it is cultivated the knowledge of moisture dependent physical properties mainly in Punjab, Uttar Pradesh, Gujarat, Maharashtra, such as spatial dimensions, bulk density, true density, and Andhra Pradesh, Assam and West Bengal (Khan et al., porosity of dill for better design of storage structures, 1993; Kokate et al., 1998). It has a long history of herbal processing equipments and processes. The frictional uses across the world since ancient era. Ebbers papyrus properties and aerodynamic properties of food materials are (C.1500 BC) reported that ancient Egyptians used dill as important for the design of efficient oil extraction, dehulling ingredients in a pain-killing mixture due to its soothing and hull separation machines. properties. Greek people used it to administer and promote good sleep in night. Seeds and green plants are used in India Physical properties of various crop seeds as pumpkin as condiments, medicine and green vegetable. The earliest (Joshi et al., 1993), cumin (Singh and Goswami, 1996), reference to use of dill seed in medicine is found in ‘Charak makhana (Jha, 1999), pigeon pea (Baryeh and Mangope, Samhita’ (700 BC), where its infusion was reported to be 2002), caper seed (Dursun and Durson, 2005), sweet corn given as cordial drink to women after confinement (Chopra (Coskun et al., 2006), red kidney beans (Isik and Unal, et al., 1956). The leaf-paste mixed with edible oil is used as 2007), chickpea seed (Nikoobin et al., 2009), locust bean a poultice for inflamed skin conditions (Kokateet al., 1998). seed (Sobukola and Onwuka, 2011) and guar (Vishwakarma The dill seed is well known for their medicinal properties, et al., 2010) have been reported. Selected engineering due to the essential oil present in them. Yield of essential oil properties of soybean (Deshpande et al., 1993), locust from Indian dill seeds vary from 1.5 to 4.5% (Randhawa, bean seed (Olajide and Ade-Omowage, 1999), sakiz faba 1985; Ahmad et al., 1990). The chief constituent of dill oil is bean (Haciseferogullari et al., 2003), cocoa (Bart-Plange carvone, a cyclic terpene ketone which is pharmaceutically and Baryeh, 2003), faba bean (Altuntas and Yildiz, 2007) important (Chopra et al., 1956; Kirtikar and Basu, 1975; and barbunia seed (Cetin, 2007) have also been studied Sarbhoy et al., 1978; Anon., 1985; Kokate et al., 1998). in the moisture content range of 18.33-32.43% (d.b.). Dill essential oil is used in preparation of dill water/gripe Gharib-Zahedi et al. (2010) and Zewdu (2011) studied water, which is administered to children suffering from some moisture dependent engineering properties of black bloat, stomach ache and hiccups. Dill is also used in various cumin and ajwain seeds, respectively. However, studies on ways in domestic treatments like decoction of sowa is in the effect of moisture content on physical properties of dill indigestion and vomiting. Besides, dill oil is also used as seed are scarce in literature. 1Central Potato Research Station, Sahaynagar, Patna-801506 (Bihar).Email: [email protected]; 2Central Institute of Post-Harvest Engineering and Technology, Ludhiana-141004 (Punjab) 33 January-March, 2016 Moisture Dependent Physical Properties of Dill The present study was, therefore, aimed to determine moisture dependent physical properties such as spatial Da = (L + W + T)/3 … (1) dimensions, geometric mean diameter, sphericity, surface area, volume, 1000-seed mass, bulk density, true density, 1/3 Dg = (LWT) … (2) porosity, angle of repose, static coefficient of friction and terminal velocity of dill seeds between 4.85 and 24.81% moisture range, dry basis (d.b.), which may be (LWT)1/3 ϕ = … (3) helpful in design of handling, processing and packaging L equipments. πB 2 L2 MATERIALS AND METHODS V = … (4) 6(2L − B) Dill seeds (variety Ajmer Dill-1) were procured from ICAR-National Research Centre on Seed Spices, Ajmer Where, (Rajasthan), India. Seeds were cleaned to remove all impurities such as dust, chaffs, stones and damaged or B = (WT)1/2 … (5) unhealthy seeds. Surface area Determination of Physical Properties The surface area (As) was determined by analogy with Moisture content a sphere of same geometric mean diameter using the Moisture content of the seeds was determined using following relationship (Mohsenin, 1986): standard hot air oven drying method at 105±1ºC for 24 h (AOAC, 1980). Test samples of the desired moisture A = π D 2 … (6) contents were prepared by adding measured amount of s g distilled water to achieve the required moisture contents, Mass of 1000 seeds followed by thorough mixing and packing in LDPE bags. The conditioned samples were kept at 5ºC in a refrigerator To determine the mass of 1000 seeds (Mt), about 250 seeds for 7 days to allow uniform distribution of moisture were randomly picked and weighed (M) on an electronic throughout the sample. Desired quantity of seeds was taken balance (Citizen Scale Inc., USA, least count 0.1 mg). The out from the bags and kept at room temperature (22-25ºC) number of seeds (n) in the sample was counted (Deshpande for 2 h before conducting an experiment (Carman, 1996; et al., 1993). The mass of 1000 seeds was calculated as; Deshpande et al., 1993; Singh and Goswami, 1996; Cetin, M 2007). M = ×1000 … (7) t n Physical properties were determined at five moisture levels at 4.85, 10.11, 14.91, 19.86 and 24.81% (d.b.) as harvesting, Bulk and true density ρ processing and storage operations of dill seed are normally Bulk density ( b) was determined following the procedure done in that range of moisture content. The experiment was reported by Singh and Goswami (1996) by filling a 500 ml replicated five times (except measurement of dimensions cylinder with the seeds from a height of 150 mm at a for which 100 seeds were taken randomly at each moisture constant rate and then weighing the contents. The seeds contents), and the average values reported. were not compacted during the test. Seed size ρ True density ( t) was determined using the toluene To determine the average size of dill, 100 seeds were displacement method. Toluene was used in place of randomly selected and the length (L), width (W), and water because the seed absorbed toluene to a lesser thickness (T) of the seeds were measured using a digital extent than that of water, and also because of its low micrometer (Mitutoyo Corporation, Japan; least count surface tension shallow dips in seeds are filled and with 0.01 mm). The arithmetic mean diameter (Da), geometric low dissolution power (Mohsenin, 1986). The volume mean diameter (Dg), sphericity (φ) and volume (V) were of toluene displaced was found by immersing a weighed calculated by using the following relationships (Mohsenin, quantity of seeds in the toluene (Mohsenin, 1986; Singh 1986; Jain and Bal, 1997): and Goswami, 1996). 34 R.K. Singh, R.K. Vishwakarma, M.K. Vishal, Deepika Goswami and R.S. Mehta JAE : 53 (1) Porosity plate, facing the test surface. The sample container was raised slightly (0.5–1.0 mm) so as not to touch the surface. The bed porosity (ε) of the bulk is the ratio of spaces in the The inclination of the test surface was increased gradually bulk to its bulk volume. Porosity was calculated using the with a screw device until the box just started to slide down following equation (Mohsenin, 1986): and the angle of tilt (α) was read from a graduated scale. The μ was taken as the tangent of this angle (Dutta et al., 1988; Joshi et al., 1993; Singh and Goswami, 1996): … (8) µ = tanα … (10) Angle of repose Terminal velocity To determine angle of repose (θ), a plywood box of Terminal velocity was measured using a cylindrical column 100×100×100 mm size with a removable front panel was in which the material was suspended in the air stream used. The box was filled with seeds and the front panel was (Nimkar and Chattopadhyay, 2001; Vishwakarma et al., quickly removed allowing the seeds to flow and assume 2010). The minimum air velocity, which held the seeds a natural slope (Joshi et al., 1993; Paksoy and Aydin, under suspension, was recorded using a digital anemometer 2004).