A study was carried out to detect the changes in colour and quality attributes of aonla juice during storage after pasteurization at different temperatures. After extracting juice from aonla cv. Chakaiya, it was pasteurized at five different temperatures and preserved with 500 ppm SO 2 in PET bottles under ambient conditions. Juice was periodically analysed for colour and chemical characters up to 9 months of storage. Though the contents of ascorbic acid and polyphenols in juice decreased with increase in storage period, the effect of pasteurization temperature was not significant. High degree of browning was observed in juice heated at higher temperatures (90 and 95°C) as compared to lower temperatures (75 and 80°C) throughout the storage period as indicated by increase in NEB values. The degree of browning was further confirmed by higher negative numerical values of whiteness index in Hunter's scale for intensity of colour. HPLC data indicated that content of gallic acid in juice decreased initially but increased sharply as the storage period prolonged. Higher amount of gallic acid was detected after 9 months of storage in juice pasteurized at 95°C than in juice heated at 75°C. The contents of kaempferol and caffeic acid decreased throughout the storage period irrespective of pasteurization temperature. Though least browning was observed in juice pasteurized at 75°C, but microbial growth was observed after 9 months of storage. Hence, pasteurization temperature of 80°C was found optimum for preservation of aonla juice under ambient conditions.

Thiamethoxam and dimethoate are two insecticides used to control hoppers and inflorescence midges in mango. Thiamethoxam (0.008 and 0.016%) and dimethoate (0.06 and 0.12%) were sprayed on Dashehari mango trees during the pre-mature stage of fruit (first week of May) to study their dissipation kinetics and risk assessment in mango fruit. Thiamethoxam dissipated in fruit from 1.93 and 3.71 mg kg(-1) after 2 h of spraying to 0.08 and 0.13 mg kg(-1) after 20 days of spraying at single and double doses, respectively. Its residue did not persist beyond 20 days in fruit. Dimethoate dissipated in fruit from 2.81 and 5.34 mg kg(-1) after 2 h of application to 0.12 and 0.19 mg kg(-1) after 10 days of application at single and double doses, respectively. No residue was detected in fruit beyond 10 days after its application. Both ready-to-harvest mature mango fruit and pulp (after 40 days of spraying) were free from any residues of these insecticides at both the concentration levels. The rate of dissipation of these insecticides followed first-order kinetics in fruit with residual half-lives of 4.0 to 4.5 days for thiamethoxam and 2 days for dimethoate. Based on their MRL values of 0.5 and 2.0 mg kg(-1) in mango, pre-harvest intervals of 7 and 11 days, and 6 and 7 days were suggested for thiamethoxam and dimethoate, respectively, after spraying at single and double doses. The theoretical maximum residue contribution (TMRC) values for both the insecticides, calculated for residues corresponding to each sampling date, were found to be below the maximum permissible intake (MPI) values on mango fruit (except for dimethoate double dose up to 3 days); hence, both thiamethoxam and dimethoate could be considered non-hazardous to consumers at the above doses and time intervals.

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An experiment was carried out to investigate the effect of post harvest spray of different concentrations (100, 200, 400, 600 and 800 ppm) of ethrel (2-chloroethyl phosphonic acid) on ripening and colour development in ‘Dashehari’ mango fruits harvested in second week of June, 2015. The treated fruits were assessed for physico-chemical parameters such as physiological loss in weight (%), firmness (Kg/cm2), TSS (°Brix), titrable acidity (%), total carotenoids (mg/100g) and peel chlorophyll (mg/100g) and observations were recorded at 2 days interval during 8 days storage at ambient temperature. Changes in total soluble solids (8.5 to 23.23° Brix), total carotenoids (0.807 to 7.12 mg/100g) and PLW (14.58%) showed increasing trends up to 8 days during storage whereas fruit firmness (8.5 to 0.68 Kg/cm2), titrable acidity (1.26 to 0.08%) and total peel chlorophyll (5.2 to 0.14 mg/100g) showed decreasing trends. At the end of the storage period for 8 days, Ethrel spray at 600 ppm induced uniform ripening with attractive yellow colour within 4 days while untreated control fruits failed to ripen uniformly and remain light green even after 8 days of storage. Ripening advances by 4 days in fruits sprayed with 600 ppm ethrel com-pared to unsprayed control fruits.