Antioxidant activities of the water-soluble fractions of glandless and glanded cottonseed protein.

To promote application of cottonseed protein products in food industry, this work measured antioxidant activities of two water soluble protein samples (Gl-L and Gd-L) isolated in a lab scale from glandless and common glanded cottonseed meal, respectively, and one soluble protein samples (Gd-P) in a pilot scale from glanded cottonseed meal. SDS-gel electrophoresis showed that the distribution patterns of the peptide fragments in Gl-L and Gd-L were similar, but more fragments and higher molecular mass bands were observed in the Gd-P gel image. While Gd-P showed the highest activities, Gl-L and Gd-L exhibited comparable 1,1-diphenyl-2-picrylhydrazyl and hydroxyl radical-scavenging activities in most cases. In contrast, Gd-P showed lower capability of inhibition of linoleic acid autoxidation than Gl-L and Gd-L. It would be of great interest in further research on these protein fractions in food products and processes (such as roasting) involved in the protective effects of food spoilage.

Survival of Salmonella during Apple Dehydration as Affected by Apple Cultivar and Antimicrobial Pretreatment.

ABSTRACT: Dehydrated fruits, including dried coconut (Cocos nucifera) and dried apple (Malus sp.) slices, have been the subject of manufacturer recalls due to contamination with Salmonella. A study was conducted to determine the survival of Salmonella on apple slices of six apple cultivars after dehydration and also following treatment with antimicrobial solutions (0.5%, w/w) and dehydration. Samples of six apple cultivars (Envy, Gala, Red Delicious, Fuji, Pink Lady, Granny Smith) were cored and sliced into 0.4-cm rings, halved, inoculated with a five-strain composite of desiccation-resistant Salmonella, and dehydrated at 60°C for 5 h. Subsequently, Gala apple slices were treated in 0.5% solutions of one of eight antimicrobial rinses for 2 min and then dehydrated at 60°C for 5 h. Antimicrobial solutions used were potassium sorbate, sodium benzoate, ascorbic acid, propionic acid, lactic acid, citric acid, fumaric acid, and sodium bisulfate. Reduction of Salmonella populations varied according to apple cultivar. Salmonella survival on Envy, Gala, Red Delicious, Fuji, Pink Lady, and Granny Smith was 5.92, 5.58, 4.83, 4.68, 4.45, and 3.84 log CFU, respectively. There was significantly greater (P < 0.05) Salmonella inactivation on Granny Smith, Pink Lady, and Fuji apples than on Gala and Envy. Survival of Salmonella on Gala apple slices following dehydration was 5.58 log CFU for the untreated control and 4.76, 3.90, 3.29, 3.13, 2.89, 2.83, 2.64, and 0.0 log CFU for those treated with potassium sorbate, sodium benzoate, ascorbic acid, propionic acid, lactic acid, citric acid, fumaric acid, and sodium bisulfate, respectively. Pretreatment of apple slices with either fumaric acid or sodium bisulfate before dehydration led to lower Salmonella survival than pretreatment with all other antimicrobial treatments. Lower apple pH was statistically correlated (P < 0.05) with decreasing survival of Salmonella following dehydration. These results may provide methodology applicable to the food industry for increasing the inactivation of Salmonella during the dehydration of apple slices.

Molecular level comparison of water extractives of maple and oak with negative and positive ion ESI FT-ICR mass spectrometry.

Soluble extractives in wood function to protect living trees from destructive agents and also contribute to wood color and fragrance. Some extractive components have biological activities with medical applications. They also play important roles in wood processing and related applications. To increase the knowledge of wood chemistry, maple and oak were extracted by water. Ultraviolet/visible (UV/vis) spectroscopy indicated the presence of a phenolic compound, resorcinol, in maple extractives having higher molecular mass and more aromatic components than oak extractives. Negative and positive electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR-MS) identified thousands of formulas in the two samples in the m/z range of 200 to 800. They mainly fall into the lignin-like, carbohydrate-like, and tannin-like compound categories. The top 25 peaks (ie, formulas) with the highest relative magnitude in negative ESI represented nearly 50% of the summed total spectral magnitude of all formulas assigned in the maple and oak extractives. Furthermore, the base peak (ie, most abundant peak) accounted for about 14% of the total abundance in each wood sample. Literature comparisons identified 17 of 20 formulas in the top five peaks of the four spectra as specific bioactive compounds in trees and other plants, implying the potential to explore utilization of maple and oak extractives for functional and medicinal applications. The various profiling of the top 25 peaks from the two samples also suggested the possible application of FT-ICR-MS for detecting chemical markers useful in profiling and identification of wood types and sources.

Effects of Particle Size on the Morphology and Water- and Thermo-Resistance of Washed Cottonseed Meal-Based Wood Adhesives.

Water washing of cottonseed meal is more cost-efficient and environmentally friendly than protein isolation by means of alkaline extraction and acidic precipitation. Thus, water-washed cottonseed meal (WCSM) is more promising as biobased wood adhesives. In this work, we examined the effects of the particle size on the morphology and adhesive performance of WCSM. Pilot-scale produced and dried WCSM was treated by three grinding methods: (1) ground by a hammer mill and passed through a 0.5-mm screen, (2) further ground by a cyclone mill and passed through a 0.5-mm screen, or (3) further ground by a ball mill and passed through a 0.18-mm screen. Micro-morphological examination revealed two types of particles. The filament-like particles were mainly fibrous materials from residual linters. Chunk-like particles were more like aggregates or accumulations of small particles, with proteins as the major component. Further grinding of the 0.5-mm Hammer product with the Cyclone and Ball mill led to more fine (smaller) particles in the WCSM products. The impact of further grinding on the dry and soaked adhesive strengths was minimal. However, the decrease of the hot and wet strengths of WCSM products by the additional grinding was significant (p ≤ 0.05). Data presented in this work is useful in developing the industrial standards of WCSM products used in wood bonding.

Purification and Host Specificity of Predatory Halobacteriovorax Isolates from Seawater.

Halobacteriovorax (formerly Bacteriovorax) is a small predatory bacterium found in the marine environment and modulates bacterial pathogens in shellfish. Four strains of Halobacteriovorax originally isolated in Vibrio parahaemolyticus O3:K6 host cells were separated from their prey by an enrichment-filtration-dilution technique for specificity testing in other bacteria. This technique was essential, since 0.45-µm filtration alone was unable to remove infectious Vibrio minicells, as determined by scanning electron microscopy and cultural methods. Purified Halobacteriovorax strains were screened for predation against other V. parahaemolyticus strains and against Vibrio vulnificus, Vibrio alginolyticus, Escherichia coli O157:H7, and Salmonella enterica serovar Typhimurium DT104, all potential threats to seafood safety. They showed high host specificity and were predatory only against strains of V. parahaemolyticus. In addition, strains of Halobacteriovorax that were predatory for E. coli O157:H7 and S. Typhimurium DT104 were isolated from a tidal river at 5 ppt salinity. In a modified plaque assay agar, they killed their respective prey over a broad range of salinities (5 to 30 ppt). Plaques became smaller as the salinity levels rose, suggesting that the lower salinities were optimal for the predators' replication. These species also showed broader host specificity, infectious against each other's original hosts as well as against V. parahaemolyticus strains. In summary, this study characterized strains of Halobacteriovorax which may be considered for use in the development of broad-based biocontrol technologies to enhance the safety of commercially marketed shellfish and other foods.

Effects of different potato cropping system approaches and water management on soilborne diseases and soil microbial communities.

Four different potato cropping systems, designed to address specific management goals of soil conservation, soil improvement, disease suppression, and a status quo standard rotation control, were evaluated for their effects on soilborne diseases of potato and soil microbial community characteristics. The status quo system (SQ) consisted of barley underseeded with red clover followed by potato (2-year). The soil-conserving system (SC) featured an additional year of forage grass and reduced tillage (3-year, barley/timothy-timothy-potato). The soil-improving system (SI) added yearly compost amendments to the SC rotation, and the disease-suppressive system (DS) featured diverse crops with known disease-suppressive capability (3-year, mustard/rapeseed-sudangrass/rye-potato). Each system was also compared with a continuous potato control (PP) and evaluated under both irrigated and nonirrigated conditions. Data collected over three potato seasons following full rotation cycles demonstrated that all rotations reduced stem canker (10 to 50%) relative to PP. The SQ, SC, and DS systems reduced black scurf (18 to 58%) relative to PP; SI reduced scurf under nonirrigated but not irrigated conditions; and scurf was lower in DS than all other systems. The SQ, SC, and DS systems also reduced common scab (15 to 45%), and scab was lower in DS than all other systems. Irrigation increased black scurf and common scab but also resulted in higher yields for most rotations. SI produced the highest yields under nonirrigated conditions, and DS produced high yields and low disease under both irrigation regimes. Each cropping system resulted in distinctive changes in soil microbial community characteristics as represented by microbial populations, substrate utilization, and fatty acid methyl-ester (FAME) profiles. SI tended to increase soil moisture, microbial populations, and activity, as well result in higher proportions of monounsaturated FAMEs and the FAME biomarker for mycorrhizae (16:1 ω6c) relative to most other rotations. DS resulted in moderate microbial populations and activity but higher substrate richness and diversity in substrate utilization profiles. DS also resulted in relatively higher proportions of FAME biomarkers for fungi (18:2 ω6c), actinomycetes, and gram-positive bacteria than most other systems, whereas PP resulted in the lowest microbial populations and activity; substrate richness and diversity; proportions of monounsaturated and polyunsaturated FAME classes; and fungal, mycorrhizae, and actinomycete FAME biomarkers of all cropping systems. Overall, soil water, soil quality, and soilborne diseases were all important factors affecting productivity, and cropping systems addressing these constraints improved production. Cropping system approaches will need to balance these factors to achieve sustainable production and disease management.

Management of Verticillium Wilt of Potato with Disease-Suppressive Green Manures and as Affected by Previous Cropping History.

The ability of disease-suppressive rotation crops to reduce potato disease problems and increase crop productivity in a field with prior severe Verticillium wilt, as well as the potential influence of previous cropping history on disease suppression, was evaluated over three field seasons in Maine. Disease-suppressive rotations consisted of: (i) a high-glucosinolate mustard blend ('Caliente 119') as a mixture of white mustard (Sinapis alba) and oriental mustard (Brassica juncea) with known biofumigation potential and (ii) a sorghum-sudangrass hybrid. Each were grown as single-season green manures followed by a subsequent potato crop. These rotations were compared with a standard barley rotation and a barley rotation followed by chemical fumigation with metam sodium as controls. Both green manure rotations significantly reduced (average reductions of 25 and 18%, respectively) Verticillium wilt in the subsequent potato crop compared with the standard barley control but were not as effective as chemical fumigation (35% reduction). The mustard blend also reduced other soilborne diseases (black scurf and common scab) better than all other rotations. Mustard blend and chemical fumigation treatments increased tuber yield relative to the barley control by 12 and 18%, respectively. However, by the second rotation cycle, disease levels were high in all rotations, and only chemical fumigation resulted in substantial disease reduction (35%). Rotations also had significant effects on soil microbiology, including soil bacterial and fungal populations and microbial community characteristics based on fatty acid profiles. However, only chemical fumigation significantly reduced soil populations of Verticillium spp. and increased general soil microbial activity. Previous cropping history did not significantly affect disease reduction, tuber yield, or soil microbial communities. This research indicates the potential for using disease-suppressive rotations for managing Verticillium wilt and other soilborne diseases but also indicates that multiple years of disease-suppressive crops may be needed to substantially reduce disease in heavily infested fields.