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Evaluation of Controlled Atmosphere and Modified Atmosphere Conditions for the Transport of Mangoes to Distant Markets

Thesis Info

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Author

Malik, Omer Hafeez

Program

PhD

Institute

University of Agriculture

City

Faisalabad

Province

Punjab

Country

Pakistan

Thesis Completing Year

2012

Thesis Completion Status

Completed

Subject

Applied Sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/2592/1/2873S.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676726117023

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This doctoral research plan (2008 to 2010) included comprehensive studies on two commercial mango cultivars of Pakistan including Sindhri and Sufaid Chaunsa with overall objective of evaluating controlled atmosphere (CA) and modified atmosphere (MA) conditions for sea-freighting mangoes to distant markets. The targeted areas included: a) Benchmark studies to monitor and document sea freight supply chain from farm to market (Germany); b) Evaluating impact of controlled and modified atmosphere storage conditions; c) Comparing open top vs. closed top boxes for sea freighting mangoes; e) Testing new chemistry fungicides for postharvest disease management, especially Stem End Rot (SER) in mango cv. Sufaid Chaunsa during long term storage and f) effects of pre-cooling on mango cv. Sufaid Chaunsa. Moreover, effect of harvest maturity (mid and late season harvest) on fruit quality and shelf life of Sindhri and Sufaid Chaunsa was also evaluated. Benchmarking studies showed that mango export supply chain to Europe (Germany) using Maersk shipping line requires about 35 days (Farm to retailing). The results revealed that poor skin colour development, skin shriveling, firmness retention in cv. Sindhri while disease development, mainly SER, (caused by organism: Botryodiplodia theobromae and Phomopsis mangiferae) in both cultivars are main issues.. The static research trials were conducted side by side to address these issues and to optimize the sea shipment protocols. Controlled atmosphere storage had significant impact on physico-chemical fruit quality and improved market value and consumer acceptability of the two cvs. Exposure to ILOS (Initial low oxygen stress) for one week had no significant negative effect; however, a concentration of 10% CO2 was found to be too high and inhibited the fruit ripening completely. These studies indicated that 1-1.5% O2 and 4-5% CO2as better CA combination for cv. Sindhri and Sufaid Chaunsa mangoes, for 4 weeks shipping period, followed by 5-7 days for post arrival handling, ripening and retailing. Mid-season harvested fruit of both cultivars showed better response in terms of better fruit marketability, less disease development and retention of the firmness of stored fruit under CA and MA conditions. Modified atmosphere packaging (MAP) trials showed that X®-tend bagging can only suppress the disease development at ripening and can be used for sea shipping mangoes to short distance markets; however the fruit with skin bruises and damages must be avoided for bagging. The experiment on packing mangoes in different types of corrugated boxes concluded that open top boxes were better option for sea shipping of the two mango cvs. since fruit developed good colour in open top boxes. Moreover, cv. Sindhri showed better shipping potential with higher percentage of marketable fruit than cv. Sufaid Chaunsa, which is more prone to post harvest diseases during long term storage. Post-harvest disease study during long term storage in cv. Sufaid Chaunsa showed that the combined application of Thiabendazole @ 2000 ppm with Prochloraz @0.5ml/L (Tank mix; HWT-52°C; 5 min) had significant disease control (i.e. stem end rot, side rot and anthracnose). Concentrations of Thiabendazole alone (1000, 1500 and 2000 ppm) did not perform well in this regard. Postharvest application of new chemistry fungicides including Amistar (0.8 ml/L) (A.I. Azoxystrobin), Nativo (0.3 g/L) (A.I. Trifloxystrobin and Tebuconazole), Cabrio Top (3 g/L) (A.I. Pyraclostrobin and Metiram) and Scholar were also found to be effective against postharvest disease development in mango. Best control was achieved by Amistar against anthracnose and stem end rot. Moreover, immediate precooling after harvest and processing gave significantly improved disease control and less weight loss in cultivar Sufaid Chaunsa. Finally, during July 2012, an industry collaborated trial shipment of cv. Sindhri was made to a commercial importer in Netherlands in which learning outcomes of these studies were intergraded from harvest to maturity and to marketing. The shipment was overall success with positive comments from importer. Some incidence of pulp breakdown in mangoes at ripe stage was observed which needs future investigation.
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میں نے محبت کو دیکھا

میں نے محبت کو دیکھا

میں نے محبت کو دیکھا'

اس کی نیم وا آنکھوں کے

          پھیلے سمندروں میں'

میں نے محبت کو دیکھا'

بچھڑتے وقت اس کے لبوں کی کپکپاہٹ میں'

میں نے محبت کو دیکھا'

خزاں زدہ شاخ پہ اٹکے زرد پتوں میں'

میں نے محبت کو دیکھا '

اسکی آنکھوں سے چھنتی سورج کی کرنوں میں'

میں نے محبت کو دیکھا'

اسے میرے کپ سے چائے کا آخری    گھونٹ پینے میں'

 

میں نے محبت کو پھیکا پڑتے دیکھا'

پرانی البم کی مدھم ہوتی تصویروں میں'

تصویروں کی اکھڑتی پرتوں میں'

دیواروں پہ ٹنگی پرانی تصویروں کے

اچانک ٹوٹ گرنے میں۔

4 Challenge and Response A Case Study of Benazir Bhutto’s Twin Prime Ministerships

Benazir Bhutto happened to be the first constitutionally chosen female leader of any Muslim country in Modern times. She ascended to office amid the legacy of General Zia-ul-Haq’s regime and civil-military bureaucracy that prompted diverse deterrence for her governments and abstained her from the application of her constitutional power. The essence of challenges was mostly political, but the grounds that created these abysses were political and gender partiality. Based on the above discourse, this article attempts to underline the torments confronted by Benazir being the new chapter in our political society. This is the empirical account of Benazir’s twin governments grounded on the views of important politicians who sight and accompanied her in her journey of power. To ponder the reasons that refrained Benazir from having true legal authority the study is divided into the following parts: (1) Challenge and response encountered by Benazir in the first tenure of her Prime Ministership (1988-90), (2) Challenge and response encountered by Benazir in the second tenure of her Prime Ministership (1993-1996). The PPP government had made some new political strides in general, but it was persistently controlled by the army. In the first government, the brass leadership and opposition and in later government civil-military bureaucracy and opposition impaired the democratic traditions. However, amid all this Benazir succeeded to do some pragmatic politics and defying the anti-PPP mindset.

Production of Bacterial Pectinase Using Submerged Culture for Various Applications

Pectinases are pectin degrading enzymes and are naturally produced by plants, animals and microorganisms. Their major source of production at industrial scale is from microorganisms especially Bacillus sp, Aspergillus sp. and yeast sp. which are generally regarded as safe. Aspergillus sp. generally produce acidic pectinases which are used in the food and beverage industry for the extraction and clarification of fruit juices and maceration of vegetables for production of purees and pastes. Bacillus sp. are usually capable of producing alkaline pectinases which have diverse functions and are in use in many industrial processes, successfully substituting the use of harsh chemicals which not only causes the deterioration of product quality but also the deterioration of environment. Pectinases from Bacillus sp. are generally active at broad ranges of pH and temperature and due to this reason, they are multi-functional enzymes. Pectinases account for more than 10% of the industrial enzymes market and they constitute 25% of the global food enzymes market. The present study was concerned with the search for a novel bacterial isolate for the lab scale production of pectinase (Polygalacturonase). Keeping in view the increasing demand of pectinase, specially its need in Faisalabad, a textile city of Pakistan, isolation of new hyper producer bacterial strains locally is an easy and cheap way of getting the desirable products at low cost. Therefore, isolation of new strains for industrial enzyme production has been, and will be, a part of research. This method alone can also provide raw material for further research such as enzyme engineering or molecular directed evolution. Pectinase positive cultures were isolated using PSAM, the medium that is able to grow and differentiate pectin consuming bacteria from others. The pectinase producing bacteria form clear halos around their colonies while others do not form any clear zones. For the identification of hyper producer strains, colony PCR was done for 16S rRNA analysis. The reason to use the 16S rRNA gene for identification purposes is that there is a large database of DNA sequences available for the gene from the widest range of microbial species as compared with any other genetic target. The selected bacterial isolate NS1 (source of pectinase enzyme) was identified based on PCR amplification of 16S rRNA and for this purpose the amplified product was electrophoresed in agarose gel against a known species of Bacillus licheniformis. The 16S rRNA sequencing confirmed the Bacillus status of the strain NS1 and the nucleotide sequence BLAST results showed 98% similarity of strain NS1 having Accession No. KX765286 with few species of Bacillus licheniformis. The growth conditions of the newly isolated Bacillus licheniformis strain were investigated using submerged fermentation to understand the fermentation behaviour of the microorganism and the pattern of pectinase production by it. The growth of the organism and enzyme production by it was investigated using some local agrowastes such as wheat bran, gram bran, citrus peel, apple pomace, carrot pomace and peanut shells as carbon sources. Among these agrowastes citrus peel powder at 2.5% concentration proved as best substrate for pectinase production followed by wheat bran. Among various nitrogen sources investigated for their role in pectinase production, organic sources such as tryptone and yeast extract gave better results than inorganic nitrogen sources. Among inorganic sources Diammonium hydrogen phosphate gave more pectinase units than other inorganic nitrogen sources. Physical parameters like pH, temperature, inocula size and incubation period for high yield of pectinase in submerged fermentation were optimized by using Response Surface Methodology. Which is an efficient tool for increasing product yield many folds in short time due to limited number of experiments and lab work. In the present study, the yield of pectinase was increased 5.6 fold that optimization produced 219U/mL as compared to one variable at a time method which produced only 38.86U/mL. Several purification methods were evaluated to observe that which one is more advantageous and cost effective in the present study for pectinase purification. Three methods of protein purification (aqueous two phase purification system, macro-affinity ligand facilitated three phase partitioning and gel filtration chromatography) were used in the present study and macro-affinity ligand facilitated three phase partitioning were found to give high purification of pectinase with purification fold of 13.05. The pectinase from newly isolated Bacillus licheniformis showed some novelty in characteristics as compared to most of the pectinases produced by other species. Although its optimum activity was achieved at a temperature of 70ºC in glycine buffer pH 8 but it also showed considerable activity (26.75U/mL) even at 100ºC in phosphate buffer pH 7. Addition of 15mM CaCO3 to the enzyme assay mixture increased the pectinase activity by 3.1 fold and addition of chloroform to enzyme assay mixture increased the pectinase activity by 7.45 fold. Surfactants (CTAB, SDS and Triton X-100) increased the pectinase activity many fold as compared to control. Among various sugars investigated for their effect on pectinase activity, sorbitol was found as a stimulator of pectinase activity by increasing its activity by 1.8 fold while glucose, lactose and sucrose inhibited its activity. The pectinase produced in this study was investigated for applications such as oil extraction from sunflower seeds, apple juice extraction and clarification and starch extraction from potatoes. In all of the above applications, the locally produced pectinase enhanced the yield of apple juice, oil and starch several fold as compared to control without the application of pectinase enzymes. Apple juice yield was increased by 2.06 fold due to pectinase treatment while the juice clarification was increased by 1.62 fold. Pectinase application also increased the oil yield some 3.15 fold as compared to oil extraction by water without the addition of pectinase. Its effect on potato starch extraction was also appreciable and 3.95 fold increase in starch yield was observed due to pectinase treatment of potato slurry. All these investigations showed that the low cost pectinase produced by locally isolated microorganisms using low cost agrowastes as nutrient supplements are able to compete with costly commercial enzymes and can bring a revolution in product quality and yield if used by local industries.