Microwave absorber utilization to improve grinding and particle surface structure characteristics of torrefied switchgrass particles for bioenergy applications.

Torrefaction treatment improves biomass grindability by transforming the fibrous herbaceous to a more brittle and lighter coal-like material. Microwave-assisted torrefaction is a promising technology for biomass conversion into energy, fuels, and chemicals. The study applied microwave absorbers in the torrefaction process to improve the thermochemical characteristics and grindability of switchgrass. Switchgrass in two particle sizes was torrefied in a microwave reactor with biochar added as a microwave absorber under inert conditions. After torrefaction, the geometric mean particle and size distribution and selected physical characteristics were evaluated, and the grindability of the torrefied ground and chopped with and without biochar were compared with those of untreated switchgrass. The geometric diameter results decreased, and the specific energy required for grinding torrefied switchgrass with biochar was significantly reduced with extended residence times and at a torrefaction temperature of 300 °C. After grinding, the lowest grinding energy of 32.82 kJ at 300 °C/20 min was recorded with torrefied ground switchgrass/biochar. The 10% biochar added/250 °C resulted in deep cell wall disarrangement, whereas at a torrefaction temperature of 300 °C, large surface deformation and carbonized weight fractions were observed.

An evaluation of IR spectroscopy for authentication of adulterated turmeric powder using pattern recognition.

Turmeric powder is a widely consumed spice, making it an attractive target for adulteration, which is not easily detected. The study examined the simultaneous use of IR spectroscopy in combination with controlled (PCA) and uncontrolled (PLS-DA and CMCA) pattern recognition techniques to detect and classify Sudan Red, starch and metanil yellow fraud in turmeric powder nondestructively. The results showed that the two major peaks in turmeric powder at 1625 cm-1 and 1600 cm-1 are not present in Sudan Red, starch and metanil yellow because these materials lack this functional group. Data distribution at the two PC locations showed clearly scattered clusters according to the four mixing studied models (turmeric powder, turmeric powder-Sudan Red mixture, turmeric powder-starch mixture and turmeric powder-metanil yellow mixture), but there was a clear overlap between turmeric powder and turmeric powder - Sudan red mixture. Both PLS-DA and SIMCA supervised methods showed satisfactory discrimination. The results also showed that in all the sample groups, when the samples were classified by PLS-DA, the values were higher compared to the SIMCA model. The overall precision of the SIMCA and PLS-DA classifier were 82% and 92%, respectively. However, when considering only two main categories adulterated (the samples at the groups 2, 3 and 4) and pure (the samples at the group 1), an acceptable degree of separation between the resulting classes was obtained. Consequently, IR spectroscopy with pattern recognition methods was found to be a promising tool for nondestructive grouping of turmeric powder samples with different types of adulteration in turmeric powder.

Instrumental measurement of pomegranate texture during four maturity stages.

Texture of pomegranate fruit and arils are the main quality attributes in the food process industries. In this study, the texture properties of pomegranate fruit and arils (cv. "Ashraf") at four different stage of maturity (88, 109, 124, and 143 days after full bloom) were evaluated using the puncture test (rupture force and rupture energy) and compression test (bioyield force, rupture energy, and young modulus). The tests showed that all studied textural parameters were sensitive textural parameters for distinguishing the maturity stages. Rupture force and rupture energy of pomegranate fruit were determined at top, middle, and bottom positions of the fruit. The results showed that compression load values of aril increased with advances in maturity stage of fruit, while puncture load values of fruit decreased. The textural properties of pomegranate fruit and arils exhibited a strong dependence (p < .05) on the degree of maturity at harvesting time. Also results showed that rupture force of three different studied positions of fruit was severely different. The highest and lowest values were observed at top and middle position, respectively.

Models for predicting the mass of lime fruits by some engineering properties.

Grading fruits based on mass is important in packaging and reduces the waste, also increases the marketing value of agricultural produce. The aim of this study was mass modeling of two major cultivars of Iranian limes based on engineering attributes. Models were classified into three: 1-Single and multiple variable regressions of lime mass and dimensional characteristics. 2-Single and multiple variable regressions of lime mass and projected areas. 3-Single regression of lime mass based on its actual volume and calculated volume assumed as ellipsoid and prolate spheroid shapes. All properties considered in the current study were found to be statistically significant (ρ < 0.01). The results indicated that mass modeling of lime based on minor diameter and first projected area are the most appropriate models in the first and the second classifications, respectively. In third classification, the best model was obtained on the basis of the prolate spheroid volume. It was finally concluded that the suitable grading system of lime mass is based on prolate spheroid volume.

Evaluation the effects of some relevant parameters on elastic modulus of pumpkin seed and its kernel.

The elastic modulus of two varieties of Iranian pumpkin seed and its kernel (namely, Zaria and Gaboor) were evaluated as a function of size (large, medium, and small), loading rate (2, 5, 8, and 10 mm/min), and moisture content (4, 7.8, 14, and 20% d.b) under quasistatic compression loading. The results showed that elastic modulus of pumpkin seed and its kernel decreased with increasing moisture content and also increasing loading rate, for the varieties under study. The average modulus of elasticity of pumpkin seed from 68.86 to 46.65 Mpa and from 97.14 to 74.93 Mpa was obtained for moisture levels ranging from 4 to 20%, for Zaria and Gaboor varieties, respectively. The elastic modulus of pumpkin seed decreased from 73.55 to 43.04 Mpa and from 101.83 to 71.32 Mpa with increasing loading rate from 2 to 10 mm/min for Zaria and Gaboor varieties, respectively.