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Controlling ethylene production and respiratory rate of climacteric fruits is reported to extend the shelf-life of those produce. The aim of this present research was to determine the effect of five (5) doses of gamma irradiation as an ethylene and respiration inhibitor on two (2) distinct varieties of plantain (Musa sp AAB) up to the onset of ripening. The variety and irradiation dose applied had a significant interaction on the number of days to the onset of fruit ripening. The daily mean ethylene production for both varieties was lowest at 200 Gy. Even though Apantu had a lower daily average as compared to Apem, it reached the onset of ripening relatively quicker than Apem. Irradiation caused a significant decrease in the respiratory rate of the plantains. Irrespective of the dose applied, the unirradiated usually had a significantly higher respiratory rate and the accompanying carbon dioxide production. Plantain varieties irradiated at 1000 Gy had the highest amount of total soluble solids contents (10.7°Brix) significantly higher than the other stages of ripening yet similar to the plantain varieties irradiated at 600 Gy (10.6°Brix), 800 Gy (10.6°Brix) and the unirradiated (0 Gy) plantain varieties (10.3°Brix). The lower levels of soluble solids may confer a better cooking quality as plantains would be less sweet and also less prone to textural breakdown when cooked.

While modern biotechnology and, specifically, genetic modification are subject of debate in many parts of the world, an increasing number of countries in Sub-Sahara Africa are making important strides towards authorizing general releases of genetically modified (GM) crop varieties for use by farmers and agribusinesses. Obviously, the documented economic and environmental benefits from planting GM crops-based on a track record of over two decades-are a major driver in the decision-making process. Another key factor is the increasing alignment of biosafety regulatory policies with progressive agricultural and rural development policies in Africa, resulting in-compared to past experiences-greater emphasis on anticipated benefits rather than risks in biosafety regulatory reviews. In several cases, this has led to expedited reviews of GM crop release applications, either for confined field trials or general environmental release, taking experiences and data from other countries into account. Such regulatory approaches hold promise as the pipeline of relevant, pro-poor GM crop applications is expanding as are the opportunities provided by novel plant breeding techniques. This review article analyses the shifting policy context in select African economies, resulting in adoption of new agricultural technology, and novel regulatory approaches used in biosafety decision-making. Case studies will be presented for Ghana, Kenya, Malawi, Nigeria and Uganda to analyze challenges, distill lessons learned and to present general policy recommendations for emerging economies.

This chapter discusses different types of composites, processing and their biodegradation studies. Polymer composites have been used in various applications, such as automotive, aerospace, construction and packaging; and their market is growing immensely. The composite reinforced with alkali-treated hemp fabrics displayed lower tensile strength and modulus as well as lower flexural strength and modulus in comparison with composites reinforced with untreated hemp fabrics. Synthetic polymers reinforced with natural fibres have been extensively used in packaging and automotive applications. Composite is an emerging area, and it offers an opportunity to replace synthetic products made from petroleum-based resources. The reason for slower degradation of biocomposites could be due to the addition of crystalline cellulose nanofibres which delays biodegradation. The crystallinity of biocomposites increased with an increase in exposure time, which could be due to the degradation in the amorphous regions by microorganisms.

In recent years, nanomaterials played a key role in developing novel polymer nanocomposites with multifunctional properties. Nanomaterials that will be reviewed in this study are nanoclays, carbonaceous (carbon nanotubes and graphene) and nanocellulose. This chapter reviews the effects of nanomaterials and nanomaterials hybrid on mechanical, thermal, rheological and dynamic mechanical properties of polymer nanocomposites. In the last decades, biobased and biodegradable polymers (biopolymers) reinforced with nanomaterials have been a research hotspot. However, this chapter also reviews the recent developments of polymer nanocomposites from biopolymers and nanomaterials.

The rate of postharvest losses is very high in plantains due to its climacteric nature. The study sought to find out the interactive effect of three different fruit packaging materials and gamma irradiation on Apantu and Apem using the amount of ethylene and carbon dioxide produced by the packaged irradiated plantain as a measure. The unirradiated (0 Gy) plantains stored in perforated polyethylene had the highest amount of ethylene produced during the storage period (456.83 μl.kg−1hr−1) while the plantains irradiated at 800 Gy and stored in whole polyethylene bags produced the least amount of ethylene during the storage period (247.67 μl.kg−1hr−1). The plantains irradiated at 200 Gy and stored in perforated polyethylene produced the highest amount of carbon dioxide during the storage period (274.33 ml CO2 kg−1hr−1) while the plantains irradiated at 800 Gy and stored in whole polyethylene bags produced the least amount of carbon dioxide during the storage period (120.50 ml CO2 kg−1hr−1). The packaging material was critical for controlling the respiratory rate of the fruit. Irradiation and packaging play a role in delaying the onset of ripening in plantain fruits.

Polyethylene was flame retarded with two intumescent-type additives, 3,5-diaminobenzoic acid phosphate and ethylenediamine phosphate, which differ with respect to their decomposition onset temperatures, along with varying ratios of two grades of expandable graphite, also differing with respect to their onset temperatures for exfoliation. Hot-pressed sheet specimens were subjected to evaluation in a cone calorimeter. Although the best char yields were obtained with formulations containing the higher decomposition temperature intumescent, 3,5-diaminobenzoic acid phosphate, the overall best performance was realized using the lower decomposition temperature intumescent, ethylenediamine phosphate, when compounded together with the low exfoliation temperature expandable graphite. These results are attributed to the formation, at the burning surface, of a more cohesive char with better thermal and mass transfer barrier properties.

The utility of expandable graphite as a flame retardant for PVC, plasticized with 60 phr of a phosphate ester, was investigated. Cone calorimeter results, at a radiant flux of 35 kW m −2 , revealed that adding only 5 wt.% expandable graphite lowered the peak heat release rate from 325 ± 11 kW m −2 to 63 ± 23 kW m −2 and the total heat release from 55 ± 11 MJ m −2 to only 10.7 ± 0.3 MJ m −2 . All samples containing expandable graphite ignited and burned only very briefly before flame out. The remarkable effectiveness of the expandable graphite is attributed to an excellent match between the exfoliation onset temperature of the graphite and the onset of decomposition of the PVC. This means that the exfoliation of the graphite forms a protective barrier layer at the right place at the right time. In addition, the simultaneous release of halogen species by the polymer matrix and the exfoliating graphite prevents the formation of a flammable air fuel mixture.

In this study, thermal-chemical and biodegradation behaviour of green composites based on flax fibres untreated and treated with alginic acid treated, and poly hydroxybutyrate-co-valerate (PHBV) were studied under composting conditions. The biodegradability of PHBV composites and neat PHBV were assayed by monitoring CO2 production from polymeric carbon under controlled aerobic composting conditions as per ASTM D5338 standard. During the biodegradation process, PHBV composites thermal-chemical and morphology properties were characterized by thermogravimetric analysis (TGA), fourier transform infra-red (FT-IR) and scanning electron microscopy (SEM) techniques. The ultimate biodegradation (mineralization) study results showed alginic acid treated flax/PHBV composites has higher rate of degradation than untreated flax/PHBV composite and neat PHBV. TGA analysis indicated that an increased t-onset temperature for alginic acid treated flax fibres/PHBV composites which was mainly due to the influence of 2% sodium alginate treated with flax fibres. FTIR results showed the increased degradation of PHBV composites was due to the hydrolytic chain scission mechanisms influenced by presence of alginic acid and flax fibres as compared to neat PHBV matrix. Morphological SEM analysis showed PHBV composites biodegradation were readily attacked by fungus but rather PHBV degradation by bacteria. This study found that the incorporation of flax fibres into PHBV matrix provides a benefit to the green composites with enhanced biodegradability.

Copyright: 2019 Wiley Online Library. Due to copyright restrictions, the attached PDF file only contains the abstract version of the full-text item. For access to the full-text item, please consult the publisher's website. The definitive version of the work is published in Macromolecular Symposia, vol 384(1), pp. 1-10

Low fruit and vegetable intake is estimated to cause about 31% of ischaemic heartdisease and 11% of stroke worldwide. It is estimated that up to 2.7 million lives couldpotentially be saved each year if fresh fruits and vegetables such as cabbageconsumption was sufficiently increased.The effect of ionizing radiation onphytochemical and sensory quality on minimally processed cabbage was studied for 15days. The aim was to investigate the effect of irradiation on phytochemical content aswell as sensory quality of cut cabbage sold in selected supermarkets in Accra, Ghana.Ascorbic acid, total antioxidant activity, total flavonoid and phenolic contents wereanalyzed for phytochemical analysis. Redox titration with iodine method was used indetermining the total ascorbic acid content while antioxidant activity, total flavonoid andphenolic content were determined by DPPH, Folin-Ciocalteu and Aluminium chloridecolorimetric method respectively. Nine-point Hedonic scale was also used for thesensory evaluation. Even though irradiation doses affected texture for that matterfirmness greatly, it showed no significant differences (p≤0.05) in phytochemical contentsuch as ascorbic acid, phenolics, flavonoids as well as antioxidant activity in theirradiated cut cabbage. Panelists' scores for colour, textue and aroma from sensoryevaluation showed significant differences (p

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