Low Density Polyethylene Bags Research Articles

A comparative study on biodegradation of low density polyethylene bags by a Rhizopus arrhizus SLNEA1 strain in batch and continuous cultures.

Biodegradation poses a challenge for environmentalists and scientific community, offering a potential solution to the plastic waste problem. This study aims to investigate the biological degradation of low-density polyethylene (LDPE) bags by a fungus in both batch and continuous cultures, with the goal of identifying an eco-friendly and cost-effective waste management strategy. The fungal strain Rhizopus arrhizus SLNEA1, isolated from a landfill located in northeastern Algeria, was tested for its capability to degrade LDPE films and utilize them as a sole carbon source in batch (α-LDPE) and continuous (γ-LDPE) cultures. The results indicated a higher rate of weight loss for γ-LDPE (29.74%) compared to α-LDPE (23.77%). The biodegradation effect was examined using scanning electron microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) to evaluate morphological and chemical changes in LDPE samples, highlighting alterations of LDPE films through cracks, veins and holes under SEM and chemical transformation and appearance of new functional groups in the FTIR data. Rhizopus arrhizus SLNEA1 demonstrated the ability to break down and utilize LDPE films as a carbon source. This isolate shows promise for LDPE biodegradation applications, which may be leveraged for the development of future plastic degradation systems involving fungi.

Effect of different packaging materials on banana ripening and shelf-life in Dang, Nepal

This research was conducted to evaluate the effect of different packaging materials on the shelf life and banana quality (cv G9) at the laboratory, Campus of Live Sciences, Tulsipur, Dang, Nepal. The different packaging materials were used as high-density non-perforated polyethylene bags, low-density non-perforated polyethylene bags, low-density perforated polyethylene bags, fiber bags, jute bags, paddy straw with cardboard, and a control treatment (in open trays). The research was conducted in a completely randomized design (CRD) with three replications. The bananas were packed in different packaging materials after being treated with a 250 ppm ethephon solution. Parameters such as peel color, physiological weight loss, pulp-to-peel ratio, total soluble solids (TSS), titratable acidity (TA), and Benedict test were assessed at two-day interval. Analysis of variance (ANOVA) showed highly significant differences for all the recorded parameters except TA. Unpackaged fruits lost 22.92% of their weight, while fruits packed in high-density non-perforated polythene (HDNP) and low-density non-perforated polythene (LDNP) bags lost 13.27% and 6.15%, respectively. Peel colour development from green mature to yellow was observed first in bananas packed in low-density perforated polyethylene (LDPP) bags followed by open trays, jute bags, and paddy straws. The lowest pulp-to-peel ratio was observed in HDNP and LDNP bags. It can be concluded that packaging bananas in high-density and low-density non-perforated polyethylene bags resulted in longer shelf life. The sweetness, aroma, and mouthfeel of bananas in jute bags, fiber bags, and paddy straws were highly accepted. Thus, LDPP bags were found effective in early ripening and uniform yellow colour development on bananas.

Comparing the effects of pristine and UV–VIS aged microplastics: Behavioural response of model terrestrial and freshwater crustaceans

Physico-chemical properties of microplastics (MPs) change during weathering in the environment. There is a lack of knowledge about the effects of such environmentally relevant MPs on organisms. We investigated: 1) the physico-chemical changes of MPs due to UV–VIS weathering, and 2) compared the effect of pristine and aged MPs on the behaviour of the water flea Daphnia magna and terrestrial crustacean Porcellio scaber. Dry powders of MPs were produced from widely used polymer types: disposable three-layer polypropylene (PP) medical masks (inner, middle and outer), polyester textile fibres, car tires and low-density polyethylene (LDPE) bags and were subjected to accelerated ultraviolet–visible (UV–VIS) ageing. Our results show that the extent of transformation depends on the type of polymer, with PP showing the most changes, followed by LDPE, textile fibres and tire particles. Obvious fragmentation was observed in PP and textile fibres. In the case of PP, but not polyester textile fibres, changes in FTIR spectra and surface properties were observed. Tire particles and LDPE did not change in size, but clear changes were observed in their FTIR spectra. Most MPs, aged and pristine, did not affect the swimming of daphnids. The only effect observed was a significant increase in path length and swimming speed for the pristine tire particles when the recording was done with particles remaining in the wells. After transfer to a clean medium, this effect was no longer present, suggesting a physical rather than chemical effect. Similarly, woodlice showed no significant avoidance response to the MPs tested, although there was a noticeable trend to avoid soils contaminated with pristine polyester textile fibers and preference towards the soils contaminated with aged MP of the middle mask layer. Overall, the apparent changes in physico-chemical properties of MPs after accelerated ageing were not reflected in their effects on woodlice and daphnids.

EFFECTS OF DIFFERENT PACKAGING MATERIALS ON THE KEEPING QUALITY OF KULIKULI

The effects of different packaging materials: plastic material, aluminium foil, glass material, low density polyethylene bag (LDPB) and a blend of plastic materials and LDPB on the keeping quality of kulikuli was studied. The quality indices studied were peroxide value, free fatty acid, saponification value and sensory attributes using standard methods. The results of the study showed that at the end of first week of storage, stored snacks exhibited different variabilities in the quality parameters measured. Snacks stored in foil paper and in a blend of plastic and LDPB had significantly (p<0.05) lower levels of quality indices measured. However, snacks stored in glass material and LDPB had higher values. At the end of the third week of storage, snack samples showed increased fatty acids, peroxide and saponification values which ranged from 8.97 – 13.46 mg/100 g, 12.40 – 13.40 meqO2/kg 84.15 – 44.80 mg KOH/g, respectively. Snacks stored in foil paper and in a blend of plastic and LDPB mantained lower levels of quality indices measured. Similarly, there were steady increase in free fatty acid, peroxide and saponification values of the snack samples with increasing storage time up to the seventh week of storage. Therefore, it can be deduced from this study that snacks stored in a blend of plastic and LDPB and foil paper alone up to three weeks maintained good product quality based on indices measured.

Co-pyrolysis of Baltic wheat straw and low-density polyethylene bags and its kinetic and thermodynamic behaviour

Wheat cultivation represents about 42 % of the total cereal cultivation area in the Baltic Sea region, generating huge amounts of wheat straw (WS) that needs to be optimally managed. In this context, this research aims to investigate the extent of using pyrolysis process in WS valorization. The experiments were performed using a thermogravimetric (TG) analyzer on WS and its mixtures with low-density polyethylene (LDPE) bags at different mixing ratios (1:1, 1:2, 1:3, 1:4). The released TG vapours were monitored using TG-Fourier transform infrared spectroscopy (TG-FTIR) and chromatography-mass spectrometry (GC-MS). The thermochemical activation energy (Ea) were studied by Kissinger-Akahira-Sunose, Flynn-Wall-Ozawa, Friedman, and Vyazovkin models. The pyrolysis results showed that WS and LDPE could be completely decomposed as a single reaction up to 600 °C and 520 °C, respectively. Aromatic-carbonyl and CO2 were the main FTIR functional group for WS vapour versus -CH2- for LEDP vapour. The GC/MS analysis of WS showed various compounds such as sec-Butylamine (11.88 %), acetic acid (10.68 %), etc., while LDPE showed many compounds without specific trend even when the heating rate was changed. While the co-pyrolysis results showed that WS/LDPE could be decomposed individually in two successive reactions at 335 °C (WS) and 495 °C (LDPE). These results were confirmed by FTIR and GC/MS which showed that the functional groups and chemical compounds of vapour generated at these decomposition zones have similar characteristics to those obtained from pyrolysis of WS and LDPE. Finally, kinetic analysis showed that WS-Baltic (227–250 kJ/mol) is more complex compared to WS-Asian (163–217 kJ/mol) due to its higher ash content. While Ea of WS/LDPE was increases upto 274–291 kJ/mol (1:1), 266–297 kJ/mol (2:1), 268–289 kJ/mol (3:1), and 278–299 kJ/mol (1:4). Also, the enthalpy, and Gibbs free energy coefficients of WS were increased by mixing (1:1) up to 272 J/mol K, while its entropy does not change much by mixing (367 J/mol K). Accordingly, the co-pyrolysis process is a key technology in valorization of WS and convert into value-added chemicals and a sustainable energy source.

Fabrication and characterization of pullulan/tapioca starch-based antibacterial films incorporated with Litsea cubeba essential oil for meat preservation

Active packaging is a novel technology that utilizes active materials to interact with products and the environment, improving food shelf life. The purpose of this work was to fabricate a multifunctional film using Litsea cubeba essential oil (LC-EO) (1 %, 3 %, 5 %, and 7 %) as the active ingredient and pullulan(P)/tapioca starch (TS) as the carrier material. Adding essential oil improves the films properties, such as barrier ability, anti-oxidant, and antibacterial activity. However, tensile strength (TS) and elongation at break (EAB) were slightly reduced from 28.94 MPa to 11.29 MPa and 15.36 % to 12.19 %. The developed PTS3% films showed the best performance in mechanical properties, especially EAB (14.26 %), WVP (3.26 %) and OP (3.13 %), respectively. The inhibitory zone diameters in the agar-well diffusion test were 18.59 mm for Staphylococcus aureus and 17.32 mm for Escherichia coli. Further study was conducted to compare the preservation effects of film with low-density polyethylene bag (LDPE) on chilled beef. Remarkably, PTS3% film decreased the bacterial population in beef meat while maintaining the pH, color, texture, and TBARS levels within an acceptable range for ten days of storage at 4 °C rather than in a low-density polyethylene bag. The outcomes indicated the potential of PTS3% films in food packaging applications.

The Role of Zeolite (Microporous Crystalline Aluminosilicates) In Catalytic Pyrolysis of Waste High- and Low-Density Polyethylene Bags for Production of Fuel and Chemicals: A Review

This review provides a state-of-the-art summary of the role which zeolite plays as a catalyst via pyrolysis as a way of recovering fuels and chemicals from waste high and or low density polyethylene bags. It also highlighted the two types of zeolite (natural or synthetic) which are used as a two-stage pyrolysis−catalysis in giving a free waxing product to pure fuel and chemicals which can be subjected to further analyzing and or upgrading. As yield of oil/wax decreased with the addition of a zeolite as catalyst from 44 and 51 wt.%, (depending on the waste high density polyethylene “HDPE” or low density polyethylene bags “LDPE” and other factors). However, the composition of the pyrolysis−catalysis oils significantly increased in aromatic hydrocarbon content accordingly. In addition, the composition of the oils shifted from high molecular weight hydrocarbons (C16+) to fuel range hydrocarbons (C5−C15), with a high content of single-ring aromatic hydrocarbons such as benzene, toluene, ethylbenzene, xylenes, and styrene. This process shows great potential for production of fuels or chemicals, and also addresses the urgent issue of waste HDPE and or LDPE disposal.

The elemental fingerprint as a potential tool for tracking the fate of real-life model nanoplastics generated from plastic consumer products in environmental systems.

Metals and metalloids are widely used in producing plastic materials as fillers and pigments, which can be used to track the environmental fate of real-life nanoplastics in environmental and biological systems. Therefore, this study investigated the metal and metalloids concentrations and fingerprint in real-life model nanoplastics generated from new plastic products (NPP) and from environmentally aged ocean plastic fragments (NPO) using single particle-inductively coupled plasma-mass spectrometry (SP-ICP-TOF-MS) and transmission electron microscopy coupled with energy dispersive X-ray spectroscopy (TEM-EDX). The new plastic products include polypropylene straws (PPS), polyethylene terephthalate bottles (PETEB), white low-density polyethylene bags (LDPEB), and polystyrene foam shipping material (PSF). All real-life model nanoplastics contained metal and metalloids, including Si, Al, Sr, Ti, Fe, Ba, Cu, Pb, Zn, Cd, and Cr, and were depleted in rare earth elements. Nanoplastics generated from the white LDPEB were rich in Ti-bearing particles, whereas those generated from PSF were rich in Cr, Ti, and Pb. The Ti/Fe in the LDPEB nanoplastics and the Cr/Fe in the PSF nanoplastics were higher than the corresponding ratios in natural soil nanoparticles (NNPs). The Si/Al ratio in the PSF nanoplastics was higher than in the NNPs, possibly due to silica-based fillers. The elemental ratio of Si/Al, Fe/Cr, and Fe/Ni in the nanoplastics derived from ocean plastic fragments was intermediate between the nanoplastics derived from real-life plastic products and NNPs, indicating a combined contribution from pigments and fillers used in plastics and from natural sources. This study provides a method to track real-life nanoplastics in controlled laboratory studies based on nanoplastic elemental fingerprints. It expands the realm of nanoplastics that can be followed based on their metallic signatures to all kinds of nanoplastics. Additionally, this study illustrates the importance of nanoplastics as a source of metals and metal-containing nanoparticles in the environment.

To study and analyse the different packaging materials on shelf-life study of banana (Musa paradisiaca var. Robusta): A Review

Packaging plays an important role to maintain the shelf life of banana thereby providing nutritional and market value alongside to the farmer losses as well. The present review study is to determine how different banana cultivars’ shelf lives were affected by the materials used for packaging. The banana cultivars, referred to locally as Robusta var., would be packed using five different materials a perforated low density polyethylene bag, dried banana leaf, gunny bag, brown paper bag, cling wrap, and no packaging material. Three replications of a factorial combination were used in the Randomized Complete Block Design experiment. Every four days, a variety of physical characteristics were evaluated, such as weight loss, pulp hardness, pulp dry matter, pulp to peel ratio, peel colour, pulp thickness, decay, and loss % of marketability. The present review revel on different packaging materials to increase shelf-life banana, latest packaging technologies used in banana’s packaging and future research in banana packaging would revel.

Soy protein isolate film activated by black seed oil nanoemulsion as a novel packaging for shelf-life extension of bulk bread.

This paper investigates the addition of lecithin-emulsified black seed oil (BSO) nanoemulsions (LNEO) and whey protein isolate-stabilized Pickering emulsions (WPEO) to soy protein isolate (SPI)-based films and their effect on improving the shelf life of bread slices. The half-life of antioxidant activity, water vapor permeability, biodegradability, density, color difference, and film thickness significantly increased (p < .05) when BSO was added. However, the incorporation of BSO significantly reduced the solubility, tensile strength, strain to break (except for WPEO), and transparency (p < .05) of the samples. The interaction between SPI film and BSO-loaded nanocarriers, as well as the morphological properties of films, was evaluated using FT-IR and FE-SEM. SPI-based films containing LNEO-5% and WPEO-5% were selected based on their mechanical and barrier properties. The effect of films on the shelf life of bread slices was investigated for 17 days of storage. LNEO samples obtained the most acceptable results in the bread in terms of sensory evaluation and color properties. According to the results, bread slices packed in SPI film containing LNEO-5% showed no signs of mold growth until the 17th day of storage, whereas the sample packed in a low-density polyethylene bag began to corrupt on the 6th day. This study highlights the potential of BSO-loaded SPI films as a novel active packaging for the bakery industry.

Physicochemical stability, microbial growth, and sensory quality of teff flour as affected by packaging materials during storage

The study evaluated the potential of four packaging materials (woven polypropylene bag, paper bag, Perdue Improved Crops Storage (PICS) bag, and polypropylene bag + low-density polyethylene bag) in preserving physicochemical, microbial, and sensory quality of teff flour over six months of storage at room temperature (14.8−26.80 °C). Results showed that hermetic packaging materials, specifically Purdue Improved Crop Storage (PICS) and Polypropylene bag + low-density Polyethylene (PP + LDPE), were the most effective in maintaining flour quality compared to non-hermetic options such as woven polypropylene bag (PP) and paper bag. As storage duration increased, there was a gradual decline in physicochemical quality, even if to varying degrees depending on the packaging material.Hermetic packaging materials (PICS and polypropylene bag + Low-density polyethylene bag) were the most effective in maintaining the quality of teff flour over time, resulting in minimal nutritional loss (0.12%–3.46%), reduced microbial growth, and preserved functional and sensory properties. On the contrary, non-hermetic packaging materials (woven polypropylene and paper bags) resulted in a higher nutritional loss (2.02%–4.62%) and significantly affected teff flour's functional and sensory properties. Therefore, the study recommends using hermetic packaging materials for better stability and quality of teff flour.

Paper Bags vis-à-vis LDPE Bags: Gleanings from Peer-reviewed E-LCA Publications

Fossil-plastics or paper? Or for that matter, bio-plastics and paper? This is a well-entrenched question in academic research, industrial, social and policy-making circles. As environmental life-cycle analyses (or more appropriately, sustainability analyses) show time and again, no single product or process or mode of operation is a ‘total villain’. There are goods and bads, and at times, more of the one than the other. This paper, which is based on a course-report written by the first author at Karlstad University (Sweden), restricts itself to a review of publications which have opted to compare paper bags with low density polyethylene (LDPE) plastic bags, on the basis of their environmental impacts. Environmental impact categories include the global warming potential, energy demand, fossil fuel depletion, water usage, acidification, eutrophication, and a range of toxicities – human, terrestrial, freshwater-aquatic and marine-aquatic. The articles were obtained through Google Scholar, read and reviewed to glean the results presented therein. The ‘What’, ‘How’ and ‘Where’, so to say were studied carefully to understand the reasons behind any differences or similarities detected. On the basis of this focused review, even though no new knowledge is being added, the common belief that the paper bag is environmentally superior to the LDPE alternative is further consolidated. However, if one focuses on water usage and would assign a high weightage to that environmental impact, LDPE perhaps may score a few ‘brownie points’ over paper. One must also not forget that plastics (LDPE in this instance) can be recycled without significant deterioration in its functional properties. In a circular economy (the bioeconomy part of which gradually will expand over time), while introducing more and more bio-based products into the technosphere by way of trans-materialization is recommended, plastics will still continue to exist – albeit in much smaller amounts – and it would be perfectly fine if the degree of recycling is augmented significantly. Speaking of a holistic sustainability analysis, the socio-economic aspects of a choice between LDPE and paper bags must also be factored in, and studied. Much-desired change happens when the top-down meets the bottom-up somewhere midway.

Postharvest shelf life extension of minimally processed kale at ambient and refrigerated storage by use of modified atmosphere.

Kale is becoming an important vegetable worldwide, mainly due to its nutritional properties. Kale leaves can be marketed whole, although minimal processing is also in demand. In this article, it was analyzed the effect of packaging in a modified atmosphere of fresh-cut kale leaves stored at 20 °C and 4 °C. Kale leaves were cut into 4 × 4 cm strips and stored in low-density polyethylene bags. Samples processed in the same way but stored in PVC were used as controls. Leaves kept in a modified atmosphere showed a delay in color change with Hue values from about 130 to 120 under PMA against 130 to 100 in control group (CTR) leaves. Chlorophyll degradation was also delayed in both storage temperatures. Samples stored under PMA showed about two times the levels of total chlorophylls with respect to CTR samples at the end of the storage. No changes in total sugar content were detected during storage and no differences were detected between control and modified atmospheres stored samples. Samples maintained in a modified atmosphere showed a lower decrement in soluble proteins and a lower rate of RUBISCO degradation at both temperatures. The relation of RUBISCO content PMA/CTR ranged from 1 to about 3 toward the end of storage No changes in phenols content were found when comparing control and treated samples. However, flavonoid and the antioxidant contents increased in samples stored in modified atmospheres with respect to their controls. We demonstrated that storage in modified atmospheres could be an adequate and simple methodology to extend postharvest life of this minimally processed product at both ambient and refrigerated storage.

Combined effects of ethylene scavenging‐active packaging system and modified atmosphere to reduce postharvest losses of ethylene sensitive produce: Banana and kiwifruit

AbstractEthylene scavenging‐active packaging is getting more interest to reduce postharvest losses of ethylene‐sensitive produce to overcome the limitations of traditional postharvest technologies. The aim of this study is to monitor behaviour of ethylene‐sensitive products to different ethylene scavenging systems combined with modified atmosphere packaging (MAP). Banana (Musa paradisicum L. var. Anamur) and kiwi (Actinidia deliciosa L. var. Hayward) were packaged with low‐density polyethylene (LDPE) bags containing ethylene scavenging sachet and ethylene scavenging‐active LDPE bags. Only passive MAP was used for bananas stored at 13°C for 12 d. Both passive and active MAP (5% O2, 5% CO2) were used for kiwi stored at 4°C for 30 d. LDPE bags with no ethylene absorber and unpackaged produces were the control groups. O2, CO2 and ethylene concentrations, mass loss, texture, colour, TSS %, titratable acidity and sensory analysis were performed during storage. O2% in the control LDPE bags decreased below 2% on 6th d, while LDPE bags containing sachet and active LDPE bags remained above critical O2 level for bananas during the entire storage. The lowest ethylene concentration was 0.45 μl L−1 in both active systems on 12th d. Equilibrium atmosphere was maintained in active and passive MAP after 5th d for kiwifruit. The lowest ethylene concentrations were determined as 0.47 μl L−1 and 0.50 μl L−1 in the sachet included LDPE and active LDPE, respectively under passive MAP at the end of the storage. In conclusion, bananas packaged with both active systems were acceptable for 9 d considering physicochemical and sensory properties. The kiwifruit was acceptable for 30 d using both ethylene absorbing systems under passive MAP.

Effect of packaging materials on lycopene vitamin C and water activity of dried tomato (Lycopersicon esculentum Mill.) powder during storage.

In this work, a storage study was conducted to find suitable packaging material for tomato powder storage. Experiments were laid out in a single factor completely randomized design (CRD) to study the effect of packaging materials on lycopene, vitamin C moisture content, and water activity of tomato powder; The factor (packaging materials) has three levels (low-density polyethylene bag, polypropylene bottle, wrapped with aluminum foils, and packed in low-density polyethylene bag) and is replicated three times. During the study, a twin layer solar tunnel dried tomato slices of var. Galilea was used. The dried tomato slices were then ground and packed (40 g each) in the packaging materials and stored at room temperature. Samples were drawn from the packages at 2-month interval for quality analysis and SAS (version 9.2) software was used for statistical analysis. From the result, higher retention of lycopene (80.13%) and vitamin C (49.32%) and a nonsignificant increase in moisture content and water activity were observed for tomato powder packed in polypropylene bottles after 6 months of storage. For low-density polyethylene packed samples and samples wrapped with aluminum foil and packed in a low-density polyethylene bag, 57.06% and 60.45% lycopene retention and 42.9% and 49.23% Vitamin C retention were observed, respectively, after 6 months of storage. Considering the results found, it can be concluded that lycopene and vitamin C content of twin layer solar tunnel dried tomato powder can be preserved at ambient temperature storage by packing in a polypropylene bottle with a safe range of moisture content and water activity levels for 6 months.

Application of Integrated Postharvest Technology for Maintaining the Quality of Methyl Bromide Fumigated Mangosteen Fruit

Methyl bromide fumigation aims to control insect infestation in mangosteen fruit before export which leads to reduce the fruit quality. Thus, the objective of this study was to control the quality of methyl bromide fumigated mangosteen using integrated postharvest technology. Fruit were prepared by fumigating with 32 g m-3 for 2 hours, washed with tap water, surfaced disinfestation with sodium hypochlorite. The prepared fruit samples were divided to treat with different methods as follows; 1) fruit were coated with ethanolic shellac-modified coconut oil (ES-MCO) and then packed in low density polyethylene (LDPE) bag containing ethylene inhibitor (1-MCP sachet), 2) fruit were coated with ES-MCO and packed in LDPE bag, 3) fruit were treated with ES-MCO and packed in nylon net bag, and 4) fruit were non-coated and packed in nylon net bag (control). All fruit samples were kept at 13ºC for 20 days (as the shipment stimulation) and then transferred to 25ºC for 2 days (as the shelf-life stimulation). The results revealed that after 15 days of storage fruit were treated with ES-MCO + LDPE bag + 1-MCP sachet showed the highest reduction of fruit rot disease and this treatment helped to delay the drying and browning of mangosteen calyx, chlorophyll degradation of the calyx, and reduce weight loss, the respiration rate and ethylene production. However after storage for 20 days, the pericarp of mangosteen in fruit treated with ES-MCO + LDPE bag + 1-MCP sachet became hard, and its shelf-life was 15 days.

Effect of Adding LDPE Bags on Rutting and Stripping Behaviour of Asphalt Mix

Disposal or incineration of waste low-density polyethylene (LDPE) bags is a major problem, as it causes pollution. The pavement over time gets deteriorated by vehicular traffic, which mostly results in rutting and other distresses. This research is based on the performance evaluation of hot mix asphalt (HMA) modified with LDPE. Aggregates National Highway Authority Pakistan (NHA) gradation B, bitumen grade 60/70 and waste LDPE bags from the dump yards of Islamabad (Pakistan) were used in this study. Penetration, ductility and softening-point tests were conducted with bitumen modified with different contents of waste LDPE bag flakes; i.e., 0%, 2%, 4%, 6% and 8% to figure out the optimum modifier content (OMC). Marshall testing was performed for the determination of optimum bitumen content (OBC). Using OBC and incorporating LDPE contents as a replacement for OBC, HMA samples were tested for performance evaluation, including rutting resistance and moisture susceptibility and compared with the performance of unmodified HMA. It was observed that 4% of LDPE as a replacement for OBC in the HMA can be used as OMC and yielded better performance results than unmodified asphalt mix. Rutting resistance was improved by 20.86% and tensile strength ratio (TSR) for moisture susceptibility evaluation was above the specified limit of 80%. KEYWORDS: Waste LDPE bags, Low-cost bitumen modifier, Performance evaluation, Performance improvement, Cost comparison, Sustainable environment.

Physicochemical properties, microbial loads and shelf life prediction of solar dried mango (Mangifera indica) and pineapple (Ananas comosus) in Tanzania

Solar drying seems to be a feasible technique for preserving and extending the shelf life of perishable fruits all year round in developing nations like Tanzania. However, there have only been a few studies on the effect of solar drying on the microbiological load and shelf-life stability of dried fruits. The purpose of this study was to examine the effects of solar drying techniques on the physicochemical properties, microbial loads, and shelf life of dried mango and pineapple. Fruits were properly cleaned, peeled, cut into 5 mm-thick slices, and dried in cabinet mixed-mode and tunnel dryers for 3 and 2 days respectively. The dried samples were packaged in high- and low-density polyethylene bags and stored at 28 °C for six months before being analyzed for moisture, aw, pH, and total bacterial and fungal loads using standard methods. Shelf life was predicted by kinetic reaction and regression analysis methods. Tunnel-dried samples had significantly (p < 0.05) lower moisture (14.0 ± 0.00–15.1 ± 0.36 g/100 g), water activity (0.45 ± 0.1–0.47 ± 0.01), pH (3.5 ± 0.15–3.6 ± 0.17), total plate count (TPC) (3.4 ± 0.09 log10 CFU g−1) and fungal loads (3.0 ± 0.1–3.1 ± 0.1 log10 CFU g−1) than cabinet-dried samples with higher values. The TPC values in all samples were below the maximum allowable limits (5 log10 CFU g−1), but the fungal loads were slightly above the limits (3 log10 CFU g−1). There were no coliforms in any of the samples. Additionally, shelf lives of 38.2–41.5 and 33.2–34.6 months were predicted for tunnel-dried and cabinet-dried samples respectively in terms of microbiological stability. Solar drying improves the physicochemical qualities, reduces microbial load, and extends the shelf life of dried fruits; hence, its application for fruit preservation combined with further studies to establish drying and storage conditions that would reduce the fungal loads to safe lower levels are recommended.

Physicochemical quality of cauliflower as influenced by cling film wrapping during storage

Compact, medium size, white to creamy cauliflower curds were packed into different packaging techniques like i. without packaging (control); ii. packed in low density polyethylene (LDPE) bag with 1% perforation; iii. wrapped with polyethylene (PE) cling film and iv. newspaper (locally used). Half of each treatment was kept at (6±1°C and 50±5% RH) and the other half was kept at ambient conditions (25±3°C and 60±5% RH). LDPE bag or PE cling film has a great effect to retain firmness and reduce weight loss of cauliflower in both storage conditions. Respiration rate, rot incidence and changes of colour values (lightness and hue angle) was reduced significantly for the cauliflowers packed in LDPE bag or wrapped with PE cling film stored in a refrigerator than that of control (without packaging) and all packaging techniques stored at ambient condition throughout the storage period. Initially, acidity, TSS and ascorbic acid content were 0.26%, 4.7° Brix and 58.7 mg 100g-1, respectively. Ascorbic acid content was reduced severely in the cauliflower stored in ambient conditions than that stored in a refrigerator. Cauliflower wrapped with PE cling film and packed in an LDPE bag (1% perforation) stored in a refrigerator (6±1°C and 50±5% RH) could retain white colour, good sensory quality, firm and fresh curds with minimum loss in weight, texture and disease incidence up to 18 days and 16 days, respectively. Int. J. Agril. Res. Innov. Tech. 12(2): 155-163, December 2022

Isolation and screening of low-density polyethylene (LDPE) bags degrading bacteria from Addis Ababa municipal solid waste disposal site “Koshe”

PurposeThis study aims to screen bacterial isolates from the Addis Ababa municipal solid waste dumping site (Koshe) for the biodegradation of low-density polyethylene bags and analyzes their efficiency in degrading plastic bags.MethodsIn this study, low-density polyethylene bag-degrading bacteria were isolated from the Koshe municipal solid waste disposal area in Addis Ababa, Ethiopia. Screening of isolates for low-density polyethylene bag biodegradation was carried out using a clear zone method. Additionally, the efficiency of the isolates for low-density polyethylene biodegradation was evaluated using the weight loss method, scanning electron microscopy analysis, and Fourier transform infrared analysis. Finally, molecular identification of potential low-density polyethylene degrader bacterial isolates was done by 16S rDNA sequencing.ResultsIsolates KS35, KS14, and KS119 resulted in significant weight loss of low-density polyethylene film (42.87 ± 1.91%, 37.2 ± 3.06%, and 23.87 ± 0.11% weight loss, respectively). These isolates were selected for further biodegradation study using scanning electron microscopy and Fourier transform infrared analysis. Scanning electron microscopy analysis shows the formation of pores, pits, and distortion of the plastic surface. Fourier transform infrared analysis indicates the appearance of new peaks at the surface of low-density polyethylene films. Phylogenetic analysis of the three potential bacterial isolates was also carried out, and the result indicates that the sequence of isolate KS35 had 99% similarity with sequences of Methylobacterium radiotolerans MN525302. Isolate KS119 had 100% similarity with Methylobacterium fujisawaense KT720189, and the sequence of isolate KS14 had 99% similarity with species of Lysinibacillus fusiformis.ConclusionsWeight loss, scanning electron microscopy analysis, and Fourier transform infrared analysis results show that isolates KS35, KS14, and KS119 have high potential in degrading low-density polyethylene bags.