Ajit K. Mahapatra

Applications of Ozone, Bacteriocins and Irradiation in Food Processing: A Review

An article is presented describing the background information on the use of ozone, bacteriocins and irradiation for destroying pathogens in food products. Their effectiveness on some pathogens of importance in food processing systems and issues of concern are highlighted. It could be concluded that although each one has the potential for use as an alternative preservation technology in specific food processing applications, no single method, except irradiation, is likely to be effective against all food spoilage and food poisoning microorganisms in all food matrices. However, the synergistic effect of one of these methods and other ‘hurdles’ or modes of food preservations could be used to ensure the microbial safety and prevention of the development of undesirable sensory and chemical changes in some food products. Bacteriocins may contribute an additional barrier in the ‘hurdle concept’ of food safety.

Influence of Moisture Content and Temperature on Thermal Conductivity and Thermal Diffusivity of Rice Flours

The thermal conductivity and thermal diffusivity for four types of rice flours and one type of rice protein were determined at temperatures ranging from 4.8 to 36.8 °C, bulk densities 535 to 875.8 kg m−3, and moisture contents 2.6 to 16.7% (w.b.), using a KD2 Thermal Properties Analyzer. The thermal conductivity of rice flours and rice protein increased with the increase in temperature, moisture content as well as with increase in bulk density. Thermal diffusivity decreased with increase in moisture content, increase in temperature and bulk density. The thermal conductivities values obtained were within the range of 0.045 to 0.124 W m−1 K−1 whereas the thermal diffusivity values were in the range of 0.094 to 0.138 mm2 s−1.

Biodiesel use and experience among state DOT agencies.

A survey of United States state transportation agencies was conducted in an effort to gather performance, storage, and economic information with the use of biodiesel blended fuel. It was observed that a high level of interest in this alternative fuel exists among state transportation agencies. Soy Methyl Ester is the dominant feedstock used as the biodiesel component. A 20% biodiesel composition was the most common blend level, with 78% of the responses reporting this level for tests or use. Blending procedures for biodiesel were not uniform or standardized. Cold weather behavior of biodiesel blended fuel was not found to be a widespread problem among state transportation agencies. The two most common deterrents to adoption were additional cost of the blended fuel and questions about cold weather behavior of the fuel.

Efficacy of low-voltage AC for inactivating surface adherent Escherichia coli O157:H7 on beef

Experiments were conducted using low-voltage alternating current (AC) to inactivate surface adherent Escherichia coli O157:H7 on beef samples. Beef samples (25 × 25 × 25 mm) were inoculated with E. coli and placed in sodium chloride solution which served as an electrolyte. Electrical current (AC) was applied to the beef samples. Frequencies of 1, 10, and 100 kHz and current intensities of 300 mA (15 mA/cm 2 ), 600 mA (30 mA/cm 2 ), and 900 mA (45 mA/cm 2 ) at treatment durations of 2, 8, and 16 min were investigated. A 2.15 log 10 reduction was achieved using a 16 min treatment time with 900 mA (45 mA/cm 2 ) current intensity and 1 kHz frequency.

Utilization of Sweet Sorghum for Ethanol Production- A Review

Sweet sorghum (Sorghum bicolor L. Moench) is an annual C4 plant of tropical origin and is a potential renewable energy crop for ethanol production. This high carbohydrate producer crop can be cultivated on marginal lands, has low input requirements and is adapted to nearly all temperate climates. Because of its readily available fermentable sugars, sweet sorghum has been identified as one of the most promising biomass crop for fermentation into fuel ethanol. This paper includes a comprehensive review of unique properties of sweet sorghum as a crop, different approaches to converting stem juice into ethanol, fermentation techniques, and technical challenges of using sweet sorghum for biofuels. The application of these techniques and the expected advancements in this field are discussed. Economics of sweet sorghum compared to other biofuel feedstocks is also covered. This review will bolster efforts aimed at using sweet sorghum as a renewable energy crop for the ethanol industry.

Synergistic Effect of Ozone and Microgard® 300 for Controlling Listeria Monocytogenes in Ready-to-Eat Cooked and Cured Ham

The effectiveness of ozone and Microgard ® (MG 300) in inactivating Listeria monocytogenes in ready-to-eat cooked and cured ham (97% fat free) was investigated in a closed system. The survival rate of Listeria monocytogenes was studied as a function of gaseous ozone concentration (0.2, 0.5 &1.0 ppm), Microgard ®(1.0, 2.0 & 3.0%), temperature (10, 15 & 20 0C) and storage period (1, 5, 10 days) for a fixed treatment period of 30 min and storage temperature of 4 0C. The results indicate that the synergistic effect of ozone, MG 300 and storage period can inactivate up to 99.94% of Listeria monocytogenes on cooked and cured ham. The treatment temperature does not have any significant effect on % kill of Listeria monocytogenes. The combination of ozone and MG 300 can be an effective hurdle to control Listeria monocytogenes in cooked and cured ham.

Flow and Thermal Properties of Stevia Powder

Abstract Stevia (Stevia rebaudiana Bertoni) has recently received a lot of attention as a sweetener due to its taste and low calorific value. Flow and thermal properties of foods play a significant role in the quantitative analysis of unit operations in the food industry. However, there are no published data available on flow and thermal properties of stevia powder. Powder Flow Tester and KD2 Pro Thermal Properties Analyzer were used to determine the flow and thermal properties of stevia powder, respectively, at different moisture contents (4.96%, 9.68%, 13.99%, 20.08%, and 25.79%, w.b.). Mean angle of internal friction of stevia powder ranged from 41.13° to 46.3°. The mean effective angle of internal friction ranged from 47.8° to 52.5° and the mean flow index ranged from 0.27 to 0.48. Mean thermal conductivity of stevia powder ranged from 0.091 W·m-2·K-1 to 0.115 W·m-2·K-1. Mean thermal diffusivity ranged from 0.103 mm2·s-1 to 0.121 mm2·s-1 and mean volumetric specific heat ranged from 0.865 MJ·m-3·K-1 to 1.019 MJ·m-3·K-1. Polynomial regression models were developed to predict flow and thermal properties of stevia powder using moisture content of stevia powder.

Evaluation of three cultivars of sweet sorghum as feedstocks for ethanol production in the Southeast United States

Sweet sorghum has become a promising alternative feedstock for biofuel production because it can be grown under reduced inputs, responds to stress more efficiently than traditional crops, and has large biomass production potential. A three-year field study was conducted to evaluate three cultivars of sweet sorghum as bioenergy crops in the Southeast United States (Fort Valley, Georgia): Dale, M81 E and Theis. Parameters evaluated were: plant density, stalk height, and diameter, number of nodes, biomass yield, juice yield, °Bx, sugar production, and theoretical ethanol yields. Yields were measured at 85, 99, and 113 days after planting. Plant fresh weight was the highest for Theis (1096 g) and the lowest for Dale (896 g). M81 E reported the highest stalk dry weight (27 Mg ha−1) and Theis reported the lowest (21 Mg ha−1). Theis ranked the highest °Bx (14.9), whereas M81 E was the lowest (13.2). Juice yield was the greatest for M81 E (10915 L ha−1) and the lowest for Dale (6724 L ha−1). Theoretical conservative sugar yield was the greatest for Theis (13 Mg ha−1) and the lowest for Dale (9 Mg ha−1). Theoretical ethanol yield was the greatest for Theis (7619 L ha−1) and the lowest for Dale (5077 L ha−1).

Prediction of Thermal Properties of Sweet Sorghum Bagasse as a Function of Moisture Content Using Artificial Neural Networks and Regression Models

Abstract Artificial neural networks (ANN) and traditional regression models were developed for prediction of thermal properties of sweet sorghum bagasse as a function of moisture content and room temperature. Predictions were made for three thermal properties: 1) thermal conductivity, 2) volumetric specific heat, and 3) thermal diffusivity. Each thermal property had five levels of moisture content (8.52%, 12.93%, 18.94%, 24.63%, and 28.62%, w. b.) and room temperature as inputs. Data were sub-partitioned for training, testing, and validation of models. Backpropagation (BP) and Kalman Filter (KF) learning algorithms were employed to develop nonparametric models between input and output data sets. Statistical indices including correlation coefficient (R) between actual and predicted outputs were produced for selecting the suitable models. Prediction plots for thermal properties indicated that the ANN models had better accuracy from unseen patterns as compared to regression models. In general, ANN models were able to strongly generalize and interpolate unseen patterns within the domain of training.

Biodiesel Use and Experience among State DOT Agencies

A survey of U.S. state transportation agencies was conducted in an effort to gather performance, storage and economic information with the use of biodiesel blended fuel. It was observed that a high level of interest in this alternative fuel exists among state transportation agencies. Soy Methyl Ester is the dominant feedstock used as the biodiesel component. A 20% biodiesel composition was the most common blend level, with 78% of the responses reporting this level for tests or use. Blending procedures for biodiesel were not uniform or standardized. Cold weather behavior of biodiesel blended fuel was not found to be a widespread problem among state transportation agencies. The most common deterrents to adoption were additional cost of the blended fuel, and questions about cold weather behavior of the fuel.