Evaluation of the potential of fungal and plant laccases for active-packaging applications

Laccases from Trametes versicolor (TvL), Myceliophthora thermophila (MtL), and Rhus vernicifera (RvL) were investigated with regard to their potential utilization as oxygen scavengers in active packages containing food susceptible to oxidation reactions. The substrate selectivity of the laccases was investigated with a set of 17 reducing substrates, mainly phenolic compounds. The temperature dependence of reactions performed at low temperatures (4-31 °C) was studied. Furthermore, the laccases were subjected to immobilization in a latex/clay matrix and drying procedures performed at temperatures up to 105 °C. The results show that it is possible to immobilize the laccases with retained activity after dispersion coating, drying at 75-105 °C, and subsequent storage of the enzyme-containing films at 4 °C. TvL and, to some extent, MtL were promiscuous with regard to their reducing substrate, in the sense that the difference in activity with the 17 substrates tested was relatively small. RvL, on the other hand, showed high selectivity, primarily toward substrates resembling its natural substrate urushiol. When tested at 7 °C, all three laccases retained >20% of the activity they had at 25 °C, which suggests that it would be possible to utilize the laccases also in refrigerated food packages. Coating and drying resulted in a remaining enzymatic activity ranging from 18 to 53%, depending on the drying conditions used. The results indicate that laccases are useful for active-packaging applications and that the selectivity for reducing substrates is an important characteristic of laccases from different sources.     

Relationship between apple peel and the whole fruit antioxidant content: year and cultivar variation

Antioxidants are usually considered with regard to plant defense mechanisms due to the oxidative stress or their importance for human health or both. In the present research, a comprehensive study was made to test the relationship between the antioxidant content in apple peel and the whole fruit in two growing seasons. Antioxidants were mainly localized in the apple peel, but cultivars exhibited very high biodiversity in the distribution pattern. High or very high correlation coefficients between apple peel glutathione reductase and catalase activity as well as ascorbate, glutathione, and anthocyanins concentrations and the whole fruit were discovered on the basis of both fresh and dry weight basis in two growing seasons: 2004 and 2005. In the case of ascorbate peroxidase activity and phenolics or flavonol contents, it was proven only in 2005. It seems that apple peel could be a good marker of health values as well as antioxidant potential of apple fruit. Additional arguments, as compared to the previous study, were incorporated to support the suggestion of glutathione reductase as worth considering as an environmental stress marker and/or signalling molecule.     

Soil fertility and establishment potential of inoculated cyanobacteria in rice crop grown under non-flooded conditions

An investigation was undertaken using a combination of microbiological and DNA-based approaches to evaluate combinations of two/three/four cyanobacterial strains (BF1 Anabaena torulosa; BF2, Nostoc carneum; BF3, Nostoc piscinale; BF4, Anabaena doliolum), using a novel vermicompost-based carrier, for their promise as inoculants in rice crop. The crop was maintained under 60% WHC through intermittent irrigation. Selected combinations (BF1 + 2 + 3; BF1 + 2 + 4; BF1 + 3 + 4) showed a consistent trend regarding their superiority over other treatments in terms of plant growth promotion and soil microbiological parameters. Microscopic examination of soil enrichment cultures raised from the treatments revealed their comparative abundance over native flora. A significant enhancement in terms of soil microbial biomass carbon and humus content was also recorded in these treatments. The soil enzymatic profile of the inoculated treatments involving FDA, dehydrogenase, acid phosphates, alkaline phosphatase, aryl esterase and β-glucosidase also revealed the promise of the inoculated strains. 16SrDNA sequencing, followed by BLAST analyses provided valuable information regarding the establishment of Anabaena strains. RFLP analyses of the 16SrDNA sequences of soil DNA and phylogenetic analyses vis a vis sequences of the inoculated cyanobacterial strains revealed the promise of treatments ?BF1 + 2 + 3, BF1 + 2 + 4 and BF1 + 3 + 4. Panicle weight (yield attribute) was statistically at par with the fertilizer controls 1/2N + PK and significantly higher than 1/3N + PK. To our knowledge, this represents a first report on evaluating the establishment of cyanobacterial inoculants in rice crop grown under non-flooded conditions (or intermittent irrigation) using a combination of agronomic, microbiological and soil DNA related attributes.     

Identification of irradiated cashew nut by electron paramagnetic resonance spectroscopy

Cashew nut samples were irradiated at gamma-radiation doses of 0.25, 0.5, 0.75, and 1 kGy, the permissible dose range for insect disinfestation of food commodities. A weak and short-lived triplet (g = 2.004 and hfcc = 30 G) along with an anisotropic signal (g perpendicular = 2.0069 and g parallel = 2.000) were produced immediately after irradiation. These signals were assigned to that of cellulose and CO 2 (-) radicals. However, the irradiated samples showed a dose-dependent increase of the central line (g = 2.0045 +/- 0.0002). The nature of the free radicals formed during conventional processing such as thermal treatment was investigated and showed an increase in intensity of the central line (g = 2.0045) similar to that of irradiation. Characteristics of the free radicals were studied by their relaxation and thermal behaviors. The present work explores the possibility to identify irradiated cashew nuts from nonirradiated ones by the thermal behaviors of the radicals beyond the period, when the characteristic electron paramagnetic resonance spectral lines of the cellulose free radicals have essentially disappeared. In addition, this study for the first time reports that relaxation behavior of the radicals could be a useful tool to distinguish between roasted and irradiated cashew nuts.     

Hydrochemistry of Arsenic-Enriched Aquifer from Rural West Bengal, India: A Study of the Arsenic Exposure and Mitigation Option

The present study aims to understand the hydrochemistry vis-à-vis As-exposure from drinking groundwater in rural Bengal. The characteristic feature of the groundwaters are low Eh (range, ?151 to ?37 mV; mean, ?68 mV) and nitrate (range, 0.01–1.7 mg/l; mean, 0.14 mg/l) followed by high alkalinity (range, 100–630 mg/l; mean, 301 mg/l), Fe (range, 0.99–38 mg/l; mean, 8.1 mg/l), phosphate (range, 0.01–15 mg/l; mean, 0.54 mg/l), hardness (range, 46–600 mg/l; mean, 245 mg/l) and sulphate (range, 0.19–88 mg/l; mean, 7.2 mg/l), indicating reducing nature of the aquifer. The land use pattern (sanitation, surface water bodies, sanitation coupled with surface water bodies and agricultural lands) demonstrates local enrichment factor for As/Fe in groundwater. Among these, sanitation is the most prevailing where groundwater is generally enriched with As (mean, 269 μg/l) and Fe (mean, 9.8 mg/l). Questionnaire survey highlights that ～70% of the villagers in the study area do not have proper sanitation. This demonstrating the local unsewered sanitation (organic waste, anthropogenic in origin) could also cause As toxicity in rural Bengal. In the agricultural lands, higher mean values of alkalinity, phosphate, sulphate, hardness and electrical conductivity was observed, and could be linked with the excessive use of fertilizers for agricultural production. Bio-markers study indicates that the accumulation of As in hair and nail is related with the construction of exposure scenario with time dimension. The strength and weakness of the on-going West Bengal and Bangladesh drinking water supply scenario and achievability towards alternative options are also evaluated.     

Genetic analysis of juvenile growth and carcass traits in a full diallel mating in selected colored broiler lines

The juvenile growth and carcass traits were evaluated in a 4 × 4 full diallel crossing involving four colored broiler chicken lines viz., Naked neck (NN), Dwarf, Punjab Broiler-1 (PB-1), and Punjab Broiler-2 to study the performance and crossbreeding parameters. The data on 2,280 chicks were analyzed using least squares techniques to assess the effect of genetic group, and the significant traits were further analyzed for crossbreeding parameters. Genetic group had significant influence on the body weights and carcass traits. The cross of PB-1 × NN recorded significantly (p ≤ 0.05) higher body weight at 6 weeks of age. The data revealed that general combining ability (GCA), specific combining ability (SCA), maternal ability (MA), sex-linked effect (SE), and purebred effects significantly influenced the growth and carcass traits in the broiler crosses. The crossbred PB-1 × NN showed positive heterosis for growth as well as carcass traits. The results suggest that GCA, SCA, SE, and MA are important in the inheritance of the body weights and carcass traits indicating the presence of both additive and nonadditive genetic variation along with reciprocal effects. Therefore, pure line selection along with development of specialized sire and dam lines followed by crossing will improve the growth performance and benefit the poultry farmers. It is concluded that PB-1 as a male line and NN as a female line performed significantly higher, therefore, may be used for improving the performance of colored broilers.     

Path Analysis of Important Growth Functions of Indian Mustard (Brassica juncea L. Czern and Coss)

Field experiment conducted at the Viswavidyalaya Farm during the winter seasons of 1980—81 to 1983—84 to study the effects of major six productive functions viz. number of inflorescence bearing primary branches, number of inflorescence bearing secondary branches, leaf area indices at flowering, number of seeds/siliqua, number of siliqua/m² and test weight of grains on the grain yields of eight elite varieties of Indian mustard ( Brassica juncea L. Czern and Coss) when sown on three different times revealed that correlations between them were close and positive in all the varieties. Path analysis of the data, further, showed that except the inflorescence bearing primary branches and the seeds/siliqua all other attributes showed high direct influences on grain yield; the maximum direct influence was obtained from number of siliqua/m².