Evaluation of Antioxidant Activity,and Nutritional and Chemical Composition of Ficus amplissima Smith Fruit

The present study was evaluated using the following in vitro antioxidant methods: 2,2′-azinobis (3-ethyl-benzothiozoline)-6-sulfonic acid disodium salt, phosphomolybdenum, ferric reducing antioxidant power, metal ion chelating activity, super oxide anion radical scavenging, hydrogen peroxide, and hydroxyl radical. Among these assays, acetone extract showed maximum free radical scavenging activity in 2,2′-azinobis (3-ethyl-benzothiozoline)-6-sulfonic acid disodium salt, phosphomolybdenum, metal ion chelating, superoxide anion, hydrogen peroxide, and hydroxyl radical assays. Moreover, the physiochemical, nutritional, and anti-nutritional parameters were analyzed. Its qualitative and quantitative composition was studied by gas chromatography-mass spectroscopy and out of 27 peaks, 27 compounds were identified. These compounds have the property of antioxidant, antimicrobial, and anti-inflammatory activity.     

Color and Texture Change Kinetics in Ripening Bananas

Kinetics of color and texture changes in ripening bananas were investigated as a function of storage temperature (10, 16, 22, 28 °C). Color was evaluated in terms of L, a and b values as well as the total color difference (ΔE) representing the residual deviations from the ripe stage. Puncture force (PF) was used to evaluate the texture properties of banana. The results indicated that the time dependence of L, ΔE and PF values followed a logistic model, while a and b values were well described by a simple zero-order and fraction conversion models, respectively. The Arrhenius equation adequately described the temperature dependence of the reaction rate constants for both color and texture parameters, from which the activation energies and rate constant at reference temperature 15 °C were obtained. There were significant linear correlations between color parameters (L, a, b, ΔE) and texture parameter (PF).     

Pathogenicity of three species of entomopathogenic nematodes to some major stored-product insect pests

Entomopathogenic nematodes (Nematoda: Heterorhabditidae and Steinernematidae) are commonly used biological control agents of insects in cryptic habitats, but their potential for suppressing stored-product insects in these habitats has not been explored previously. Here, we provide data from the first step in a program to evaluate entomopathogenic nematodes in the genus Steinernema as biological control agents of stored-product pests by determining their pathogenicity to some of the major stored-product pest species. When evaluated against larvae, pupae and adults of six pest species (Plodia interpunctella, Ephestia kuehniella, Oryzaephilus surinamensis, Tenebrio molitor, Tribolium castaneum, and Trogoderma variabile), and the adults of two additional pest species (Sitophilus oryzae and Rhyzopertha dominica), Steinernema riobrave was either the most pathogenic or of similar pathogenicity compared to S. carpocapsae and S. feltiae. A dose of 10 infective juveniles of S. riobrave caused 80% or higher mortality against larvae of P. interpunctella, E. kuehniella, T. castaneum, and O. surinamensis, pupae of T. castaneum and T. molitor, and adults of T. molitor and the two moth species. All stages of Trogoderma variabile exhibited 70% or higher mortality. Adults of S. oryzae and R. dominica exhibited low susceptibility with 15% and 35% mortality, respectively. On the basis of these results, S. riobrave was selected for further evaluation under more field-like conditions.     

Inactivation Kinetics of Geobacillus stearothermophilus Spores in Water Using High-pressure Processing at Elevated Temperatures

ABSTRACT: Establishment of a high-pressure sterilization process requires data on pressure and temperature-dependent inactivation kinetics of target pathogenic, spoilage, or surrogate spore-forming bacteria in the food being tested. The objective of this study was to examine the response of Geobacillus stearothermophilus ATCC10149 spores to various temperature, time, and pressure combination treatments (500 to 700 MPa; 92°C to 111°C, 0.01 to 360 s). The pressure inactivation of spores was characterized at elevated temperatures under isobaric and isothermal conditions during the holding time using a laboratory-scale high-pressure unit. The inactivation kinetics was well described by the log-linear regression model. As expected, the rate of spore inactivation increased with increasing pressure and temperature. Decimal reduction times at constant pressure ( D _T,P values) varied from 29.4 to 108.8 s at 92°C, 17.4 to 76 s at 100°C, and 6.1 to 51.3 s at 111°C within the pressure range of 500 to 700 MPa. The resistance of spores to temperature and pressure was characterized with z_T and z_P values and compared with their resistance to conventional steam heating. The conventional thermal resistance of G. stearothermophilus species did not correlate to the thermal resistance at high pressure. The study provides kinetic data on the effects of pressure and temperature on the inactivation of a heat-resistant bacterial spore species under conditions applicable to the commercial processing of low-acid foods.     

Effect of inoculum level on aflatoxin production by Aspergillus flavus under modified atmosphere packaging (MAP) conditions

The combined effect of inoculum level and other environmental factors (water activity, storage temperature and level of headspace oxygen) on the growth and aflatoxin production by Aspergillus flavus under MAP conditions on a synthetic medium was studied using a full factorial experimental design. Regression analysis of the data showed that inoculum level, water activity (a_w), storage temperature and headspace O₂ all had a significant effect on both growth of, and aflatoxin production by, A. flavus. Maximum growth (4·17 mg g^-1) occurred at an inoculum level of 10⁴ spores per plate, an a_w of 0·95, storage temperature of 20°C and headspace O₂ of 15% (balance CO₂:N₂ (60%:40%)). However, maximum aflatoxin level of 3·45 μg g^-1 (3450 ng g^-1) occurred at an inoculum level of 10³ spores per plate, an a_w of 0·96, storage temperature of 25°C and a reduced level of headspace O₂ (10%). Packing under almost completely anaerobic conditions using Ageless oxygen absorbents inhibited both growth and aflatoxin production by A. flavus, irrespective of the inoculum levels and storage temperature used.     

Rheological characteristics of tamarind (Tamarindus indica L.) juice concentrates

The steady-shear and small-amplitude oscillatory rheological properties of tamarind (Tamarindus indica L.) juice concentrate (TJC) were studied in the temperature range of 10-90 °C using a controlled-stress rheometer. Under steady-shear deformation tests, shear stress-shear rate data were adequately fitted to the Herschel-Bulkley and Casson model at lower (10-30 °C) and higher (50−90 °C) temperature range, respectively. The Carreau model was applied to describe the shear-thinning behaviour of the concentrate, and the model parameters estimated empirically showed temperature dependence. Oscillatory shear data of TJC revealed predominating viscous behaviour (G″>G′) at lower frequency range while the elastic modulus predominating over the viscous one (G′>G″) at higher frequency range. The Cox-Merz rule that relates steady shear and dynamic material functions was tested and not followed by most of the temperatures. The specific heat of TJC increased with temperature and the glass transition temperature of the product was found to be −70.74 °C.     

Rate of release of spruce budworm pheromone from virgin females and synthetic lures

The rate of pheromone [(E)- and (Z)-11-tetradecenal] release from calling virginChoristoneura fumiferana females and synthetic lures was determined in both static and aerated atmospheres. In a static system ca. 2 ng/hr was recovered per female. Owing to the > 75% adsorption onto the females' bodies in static atmospheres, the actual release rate has to be corrected to roughly 9–27 ng/hr, depending on the percentage adsorbed. In the air-flow system, females were found to release between 4 and 20 ng/hr. On a 168 light-dark cycle, calling began 1–2 hr before lights-off and continued nonstop until lights-on. Pheromone was emitted throughout calling, while no pheromone was detected during the noncalling periods.Lepidoptera: Tortricidae.Published as Journal Article No. 10258 of the Michigan Agricultural Experiment Station.     

Measurement and targeting of thermophysical properties of carrot and meat based alginate particles for thermal processing applications

The objective of the study was to investigate the thermo-physical properties of meat and carrot based alginate particles as influenced by the formulation variables. A response surface methodology (RSM) was used to study the effect of sodium alginate concentration, calcium chloride concentration and dipping time in the calcium chloride solution, at five levels each, on the thermo-physical properties of the fabricated particles (9 mm in diameter and 9 mm in height). Density was similar for all conditions. Increasing sodium alginate concentration resulted in a significant decrease in the heat capacity and thermal conductivity values. These changes were primarily attributed to the lowering of moisture content of the particles resulting from the treatment. Using RSM, optimum conditions for fabricating particles having similar thermo-physical properties to real foods were obtained as 5.3% and 4.9% sodium alginate, 2.2% calcium chloride and 14.2 and 36.0 h immersion in the calcium chloride solution for meat and carrot alginate particles, respectively.     

High pressure gelation of soy proteins: Effect of concentration, pH and additives

The global demand for soybean protein has increased dramatically over the last few years due to its versatility. High pressure (HP) processing is emerging as an effective alternative to thermal processing of foods. The HP treatment of protein solutions at different process conditions can cause partial unfolding of proteins that can lead to the irreversible gelation of the product. In this study, the influence of protein concentration (5–20% w/v), pH (3–7), sugar (5% w/v), CaCl₂ (5% w/v), pressure level (up to 650 MPa) and holding time (0.1 and 10 min), and process temperature (20 and 40 °C) on the dynamic rheology of soybean protein concentrate (SPC) solutions was evaluated. Furthermore, the protein structural changes caused by HP were studied, through the use of the extrinsic fluorescence of the probe 8-anilino-1-naphthalene sulfonic acid (ANS) and Fourier transform infrared (FTIR) spectroscopy. Results indicated a strong influence of protein concentration on both elastic (G′) and viscous (G″) moduli, increasing with concentration. Increase in pressure and holding time produced an increase on both G′ and G″ for SPC concentrations higher than 10%; at 15% SPC concentration, a relatively low pressure treatment of 250 MPa achieved the cross-over of G′ over G″. The structure of the soybean proteins suffered limited changes after HP treatment; hydrophobicity increased, as well as the relative proportion of random coil, while the β-sheet content decreased. HP treatment can be used to enhance the viscoelastic behavior of SPC after which SPC can be used to enrich both protein content and textural properties of foods.