Thermal properties of cryo-ground fenugreek powder

Thermal properties, viz., specific heat, thermal conductivity and thermal diffusivity of fenugreek (cv. AM-2) powder were determined. Specific heat increased from 295.9 to 5794.4 J kg-1 K-1 with increasing temperature from -150°C to 100°C and moisture content from 5.5% to 25.2% d.b. and exhibited second order polynomial relationship. Thermal conductivity and thermal diffusivity ranged from 0.140-0.186 W m-1 K-1 and 8.13 × 10-6-11.38 × 10-6 m2 s-1, respectively with increasing moisture content. Thermal conductivity and thermal diffusivity showed quadratic relationships with moisture content. Specific heat of fenugreek powder was significantly affected by moisture content and temperature (P<0.01), while thermal conductivity and thermal diffusivity were significantly affected by moisture content (P<0.01). &nbsp

Selected thermal properties of cryo-ground coriander powder (var. RCR-41)

Thermal properties of cryo-ground coriander powder (var. RCR-41) such as specific heat, bulk thermal conductivity and bulk thermal diffusivity were investigated. It was observed that the specific heat increased from 347.63 to 3700.31 J kg-1K-1 with increase in temperature from -150 °C to 100°C and moisture content from 3.5% to 17.7% (db) and it showed a second order polynomial relationship with moisture content and temperature. The thermal conductivity increased nonlinearly from 0.0884 to 0.1340 Wm-1K-1 with increase in moisture content from 3.5% to 17.7% (db) at 30°C. Thermal diffusivity varied non-linearly from 12.63 × 10-6 to 19.89 × 10-6 m2s-1 with increase in moisture content from 3.5% to 17.7% (db) at 30°C. Both thermal conductivity and thermal diffusivity showed quadratic relationships with moisture content. The specific heat was affected significantly with moisture content and temperature (P≤0.01) and both thermal conductivity and thermal diffusivity were affected significantly by moisture content. &nbsp

Thermal properties of cryo-ground powder of black pepper (Panniyur 1)

The thermal properties of black pepper powder, namely specific heat, thermal conductivity and thermal diffusivity were investigated. The specific heat increased from 225.68 to 4479.53 J kg-1 K-1 with increase in temperature from -150 to 100°C and moisture content from 3.3% to 18.2% dry basis and it showed a second order polynomial relationship with temperature and moisture content. The thermal conductivity increased non-linearly from 0.1161 to 0.1844 W m-1 K-1 with increase in moisture content from 3.3% to 18.2% dry basis at 30oC. The thermal diffusivity increased non-linearly from 10.86 × 10-6 to 17.36 × 10-6 m2 s-1 with increase in moisture content from 3.3% to 18.2% dry basis at 30°C. The thermal conductivity and thermal diffusivity showed quadratic relationships with moisture content. The specific heat was affected significantly with moisture content and temperature (P<0.01). The thermal conductivity and thermal diffusivity were affected significantly by moisture content. &nbsp

Effect of cryogenic grinding on phenolic compounds and antioxidant properties of fenugreek (Trigonella foenum-graecum L.) seed extract

Effect of cryogenic grinding on oil content, total phenolics, flavonoid content and anti-oxidant properties of seed extract of three fenugreek (Trigonella foenum-graecum) genotypes AM 1, RMt 1 and RMt 305 have been analyzed. Oil content was 37.36% more in cryogenically ground sample of genotype AM 1. Yield of methanol crude seed extract was 76.75% more in cryo ground sample of genotype AM 1. Total phenolic content (TPC) was also high in cryo ground samples of all three genotypes. It ranged from a minimum of 75.72 mg in RMt 1 to a maximum of 94.03 mg gallic acid equivalent (GAE) g-1 crude seed extract in genotype AM 1. Similarly total flavanoid content (TFC) was also increased in all cryogenically ground samples and ranged from 17.75 mg in RMt 305 to 26.37mg quercetin equivalents g-1 crude seed extract in genotype AM 1. Methanol crude seed extract of all genotypes were evaluated for its antioxidant activity in terms of total antioxidant content (AOC), 1, 1-Diphenyl-2-picrylhydrazin (DPPH) free radical scavenging % and EC50 value. The amount of total antioxidant content in cryo ground seeds was significantly high in all genotypes ranging from 9.32 mg in genotype RMt 1 to 11.08 mg butyl hydroxyl toluene (BHT) Equivalent g-1 crude seed extract in RMt 305. DPPH scavenging % was invariably more in cryo ground seeds in all three genotypes. Higher concentration of antioxidant content and DPPH scavenging % suggested high antioxidant activity in cryo ground samples. &nbsp

Characteristics of Different Systems for the Solar Drying of Crops

Solar dryers are used to enable the preservation of agricultural crops, food processing industries for dehydration of fruits and vegetables, fish and meat drying, dairy industries for production of milk powder, seasoning of wood and timber, textile industries for drying of textile materials. The fundamental concepts and contexts of their use to dry crops is discussed in the chapter. It is shown that solar drying is the outcome of complex interactions particular between the intensity and duration of solar energy, the prevailing ambient relative humidity and temperature, the characteristics of the particular crop and its pre-preparation and the design and operation of the solar dryer