Red pears had higher PPO activity, total phenolics and chlorogenic acid concentration than Bosc pears. PPO activity and phenolics both decreased in fruits held at room temperature. pH and temperature optima for Bosc and Red pears PPOs were 5.0 and 5.5, and 20 and 23C, respectively. 4‐Methylcatechol, catechol and dopamine were good substrates for PPO from both pear cultivars; however, no activity was observed with any of the mono‐hydroxy substrates studied. Higher Km and lower Vmax values were observed for Bosc pear PPO. Heating at 75C for 30 min completely inactivated the enzyme from both cultivars. Heating at 55 and 65C for the same duration resulted in partial inactivation (45–60%) of this enzyme. Ascorbic acid, L‐cysteine, sodium metabisulfite and thiourea effectively inhibited browning due to pear PPOs.

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In South Asia, the high costs of synthetic fertilizers have imposed research on alternative nutrient inputs. We aimed to identify potential trace elements (PTE) present in some organic manure that might be a source of environmental pollutions and risk to public health following consumption. The study aims to evaluate how different organic waste (poultry waste, PW; press mud, PM; and farmyard manure, FYM) influences the heavy metal migration in soil, the accumulation in garlic, and their potential health risks. Organic waste caused a higher accumulation of certain metals (Zn, Cu, Fe, and Co), whereas Mn, Cd, Cr, and Pb were in lower concentrations in soil. Amendments of soil with PM revealed a higher accumulation of Cd, Cr, Fe, and Pb, whereas PW resulted in Cu and Zn accumulation in garlic. Treatment of soil with FYM exhibited higher metal concentration of Co and Mn. An environmental hazard indices study revealed that pollution load index (PLI) was highest for Cu following treatment with PM. The health risk index (HRI) was greater for Cd following amendment with PM. Maximum daily intake of metals (DIM) was observed for Zn after treatment with PW. The Pb exhibited maximum bioconcentration factor (BCF) in PM-amended plants. Based on these findings, we concluded that garlic grown on contaminated soil with organic waste may pose serious health hazards following consumption.

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Ijaz Rasool Noorka. Effect of different concentrations of municipal solid waste on metal uptake of wheat (Triticum aestivum). AbstractHeavy metal accumulation in edible parts of plants is major international concern now a day. This research was aimed to observe the influence of different level of municipal solid waste on metal accumulation by wheat variety (Inqalab-91). The metal concentration in soil and wheat grains was quantified using atomic absorption spectrophotometer (AA-6300 Shimadzu Japan). Results demonstrated that municipal solid waste treatment increased the heavy metals in various parts (root, shoot, grains) of wheat plant. The metals in wheat grains varied from 1.5-2.46, 10-18.16, 0.8-0.95 and 0.53-0.95 mg/kg for Cd, Fe, Zn and Co, respectively. The amount of all heavy metals were determined within the permissible range except for Cd. The cadmium had the highest bio concentration and enrichment factor. The pollution load index values for Cd and Co were the highest. The health risk index values for Cd, Fe and Co were ˃ 1 indicating that wheat grains were not suitable for human consumption. So, it is concluded that proper treatment of municipal solid waste is necessary before its application on land.