Field studies are necessary to understand the abundance and type of indigenous arbuscular mycorrhizal (AM) fungi present in the rhizosphere. Green gram [Phaseolus aureus Roxb. (= Vigna radiata var. radiata)] is a major pulse crop of South India. A field study was conducted to identify the AM fungi associated with green gram under field conditions in this region. The rhizosphere soil samples from these fields were analyzed for AM fungal spores. Glomus mosseae, Glomus microcarpum, Gigaspora margarita, and Scutellospora sp. were identified as the AM fungi associated with green gram. Glomus mosseae was the most frequent AM fungal associate identified in 81%, G. microcarpum and G. margarita in 24% each, and Scutellospora sp. in 5% of the soils studied. The range of distribution varied from a single species of AM fungus to three species belonging to two genera in one sample. Correlations of spore count and percentage colonization for all the AM fungi on the crop in the field, along with soil parameters like pH, N, P, and K were studied. Significant negative correlation (P < 0.01) was obtained between percentage colonization and P. The pH and N were positively correlated (P < 0.01) with K. The study indicates involvement of factors other than soil nutrients in the distribution and sporulation of AM fungi.

The chemical nature of the polyphenols of cashew kernel testa has been determined. Testa contains tannins, which present large molecular complexity and has an ancient use as tanning agents. The use of tannins extracted from cashew testa, considered in many places as a waste, grants an extra value to the cashew. In this work we have analysed through high performance liquid chromatography, infrared spectroscopy (FT-IR) and thermo gravimetric analysis the average molecular weight, main functional groups and thermal properties of tannins extracted from Anacardium occidentale L. The results of these analyses are compared with the commercial grade tannic acid. The FT-IR spectra showed bands characteristic of C = C, C-C and OH bonds. This important bioactive compound present in the cashew nut kernel testa was suggested as an interesting economical source of antioxidants for use in the food and nutraceutical industry.

The equilibrium moisture content (EMC) of raw cashew nuts (RCN) were determined using the standard static gravimetric method at 30°C, 40°C and 50°C for relative humidity (RH) ranging from 43 to 90 %. The proximate composition analysis, peroxide value and iodine value of RCN were assessed at this equilibrium stage. The RCN kept under the humidity of 86 and 90 percentage at all studied temperatures developed mold growth within 24-48 h of time. The better storage condition assessed for raw cashew nut is 67 % of RH at 30°C and the values obtained for EMC, proximate composition analysis, peroxide value and iodine value are within the same range as observed with harvested RCN. Highlights • Raw cashew nut storage condition identified • It was analysed with different temperature (30°C, 40°C and 50°C) and relative humidity (43 %-90 %) • Better storage condition for raw cashew nut is in 67 % of RH at 30°C • In this condition the EMC was 8.11 % as within the range of moisture in harvested RCN

The use of better carbon sources and efficient production strains were deemed as promising strategies to economize tannase production. A novel agro-residue, cashew testa, was tested for the production of tannase under solid-state fermentation (SSF) using Aspergillus niger CEPC 11. CEPC 11 was identified by 18S rDNA typing as Aspergillus niger and deposited in International depositing Authority under MTCC number 5898 and NCBI accession number KM516789. The enzyme was purified 11 fold to obtain tannase with a specific activity of 10.22 U/mg and final yield of 48 %. SDS-PAGE analysis of purified enzyme gave a single band of 89.9KDa. The optimal temperature was found to be 40°C, with an active range of 25-60°C. The optimal pH was 5.5, and the enzyme was inactive at pH 8.0. The enzyme was identified through MALDI-TOF-MS tandem mass spectrometry as tannase. Km and Vmax were recorded at 0.1133 M (substrate concentration) and 44.79 μmol/min respectively. Heavy metals (Cadmium, Nickel, Lead, and Copper) in tannery effluent were analyzed before and after treatment with enzyme by AAS (Atomic Absorption spectroscopy). Gallic acid is also determined as an inter-mediatory by-product of this technology. Treatment with tannase enzyme improved the quality of fruit juices. This is the first report on production of tannase by Aspergillus niger under SSF with cashew industry by-product cashew testa as the substrate. The use of residues is an alternative to solve pollution problems that can be caused by an incorrect environmental disposal.

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