Effect of mechanical damage on the quality characteristics of banana fruits during short-term storage

Fresh fruits like bananas are very susceptible to mechanical damage during postharvest handling which can result in a substantial decline in quality. The study aims to evaluate the effect of bruise damage and storage temperatures on the quality of banana fruits after 48 h storage. Each ‘Grand Naine’ banana fruit was impacted once by using a drop impact test using three different heights (10, 30, and 50 cm) and storage temperatures (13 and 22 °C) after 48 h of storage. Different quality analyses were measured like bruise measurements (impact energy, bruise area, bruise volume, and bruise susceptibility), weight loss, total soluble solids (TSS), color (L*, a*, b*, hue°, chroma, yellowness index, yellowness value) headspace gases (respiration and ethylene production rate). The results showed that bruise measurements (bruise area, bruise volume, and bruise susceptibility) were highly affected by drop height. The quality parameters like weight, color, total soluble solids and headspace gases were affected by drop height and storage condition. Weight loss, total soluble solids, respiration rate, and ethylene production rate increased as drop height and storage temperature rise. Storage at ambient conditions (22 °C) accelerated bruising occurrence in banana fruits. Fewer changes were observed after 48 h of storage. The least value of yellowness index was observed on the non-bruised banana fruits (84.03) under 13 °C storage conditions. The findings of the study can provide baseline data to understand the mechanical damage mechanism on fruit quality, hoping to create awareness and educate farming communities and consumers. Storage temperature management is another approach that needs to be followed to reduce the occurrence of mechanical damage in fresh produce.

Investigation into the effect of resin finish on the functional characteristics of plain fabrics using different curing methods

Purpose Cellulosic fabric and plain weave are the most commonly used material in home textiles. The poor wrinkling, dimensional stability and pilling are some of the problems faced during usage. The textile industries apply resin finish to improve these characteristics. The purpose of this study is to improve pilling resistance, dimensional stability and smoothness appearance (SA) of rayon and rayon/cotton plain fabrics using different concentrations of dimethyloldihydroxyethylene urea (DMDHEU) and acrylic copolymer. The finish was fixed using two different fixation methods. Design/methodology/approach Three concentrations, 40, 100 and 150 g/l of Arkofix NF (DMDHE based) and Appretan N9211 (acrylic copolymer), were taken. The finish was applied at normal and shock cure. The effects of finish on pilling resistance, dimensional stability, smoothness, tear strength, light fastness, Berger whiteness and yellowness index of plain fabrics were investigated. Findings The changes in the characteristics of the finished fabrics were compared with unfinished fabrics. This study revealed that at 40 g/l of Arkofix NF and Appretan N9211 using a normal cure would improve the pilling resistance, dimensional stability and SA of the plain fabrics. Whereas, there was no adverse effect observed on tear strength, light fastness, Berger whiteness and yellowness index of plain fabrics at these conditions. Originality/value Unlike the previous studies, this paper proposed the single finish formulation where the functional characteristics of the plain rayon and rayon cotton fabrics meet the general requirement of a customer.

Smart Cotton Functionalized With Self-Implanted Palladium Nanopanicles: Full Ultraviolet Shielding Potency

Unique technique is currently demonstrated for preparation of ultraviolet protective cotton fabrics with full shielding effect, via self-implantation of palladium nanopanciles. Palladium (Pd) nanopanciles were in-situ immobilized within native & cationized cotton using two different concentrations of palladium precursor (20 & 60 mM) under strong acidic (pH 2) and basic (pH 11.5) media. Cationization (50% and 100%) of cotton fabrics was performed in order to increase the accessibility of fabric for controllable implantation of palladium nanopanciles. Size distribution of palladium nanopanciles in supernatant solution was estimated via Transmission electron microscopy to be 3.2 nm. The estimated data showed that the sample prepared with the highest cationization percent and highest concentration of palladium precursor in strong alkaline medium exhibited the highest yellowness index, color strength and excellent ultraviolet shielding effects. The yellowness index was significantly increased from 15.67 for cationized cotton to 74.99 for the sample prepared with the highest cationization percent and highest concentration of Pd+2 in alkaline medium (Pd-CC (100)4). Tensile strength was insignificantly decreased from 93.2 MPa for cationized cotton to 84.5 MPa for Pd-CC (100)4. Ultraviolet shielding effect was superiorly enhanced with implantation of palladium nanopanciles. The UV protection factor (UPF) was also excellency increased from 1.3 (insufficient) for native cotton to 256.6 (excellent) for Pd-CC (100)4.

Silica derived from variety of sources and its functionalized forms as an antiblock additive in polypropylene

Silica derived from variety of sources and its functionalized form has been studied as an antiblock additive in polypropylene (PP). Commonly inorganic antiblock additives are added to PP films to reduce the blocking and facilitate separation of polymeric films. However, such types of additives can cause a reduction of clarity in transparent films. In the present work, comparative analysis of silica obtained from various sources specifically from rice husk ash and its further functionalization/modifications using n-octyltriethoxysilane has been performed. Since silica synthesized via rice husk ash was obtained from waste (rice husk ash), this further solves the problem of ash disposal. The functionalized silica has been characterized using Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). The morphological analysis and particle shape and size has been characterized by scanning electron microscopy (SEM). The melt flow index (MFI), yellowness index and other mechanical characterizations including tensile and impact strength was performed for 30–40 µm thick tubular quenched polypropylene (TQPP) films. These films were evaluated to have high transmittance (above 93%), high clarity (above 98%) and very low haze (less than 2%) indicating the high transparency and improved optical properties. The blocking force and optical properties are quite similar for TQPP film containing silica synthesized from rice husk ash and commercial grade silica and hence, proving silica synthesized from rice husk ash to be an effective substitute for commercial silica in TQPP films.

Evaluation of Some Selected Mango Varieties for Fruit Powder Production In Ghana

Mango is an important fruit, which receives high patronage in Ghana. However, the highly seasonal and perishable nature of the crop, besides being a constraint to both farmers and processors, also deny consumers the opportunity to enjoy the fruit all year round. Use of the stable powder form of mango can serve to fill the gap during the mango off-season. This study evaluated the fruits of four major mango varieties (“Keitt”, “Kent”, “Palmer” and a local variety) grown in Ghana for their suitability for fruit powder production. The fresh fruit pulp and reconstituted freeze-dried powder of the varieties were analyzed for physicochemical characteristics. The study revealed that “Keitt”, “Kent” and “Palmer”, which are the exotic varieties, had significantly (p≤0.05) high pulp content of 68%, 66% and 63% respectively indicating potential for high fruit powder yield. Acceptable levels of total soluble solids, titratable acidity, ascorbic acid and beta-carotene contents were observed in the fresh fruit and the freeze-dried powders of the varieties. There was no significant (p≤0.05) difference in Yellowness Index between fresh fruit pulp of “Keitt”, “Kent” and “Palmer” and their respective reconstituted freeze-dried powders. These three mango varieties exhibited considerably good quality in terms of physical and chemical characteristics for processing and utilization as fruit powder. The production of high quality mango powder from these varieties could therefore serve as substitutes in the off-season and also reduce postharvest loss.

Colour Stabilisation of Surface of Four Thermally Modified Woods with Saturated Water Vapour by Finishes

This paper deals with the influence of the type of transparent surface finish on the change of colour of the surfaces of native wood, and thermally treated wood, with saturated water vapour. In the experiment, alder, European beech, Paper birch, and Norway maple wood were thermally treated at a temperature of 135 °C under saturated water vapour for six hours. Three various types of surface finishes (acrylic-polyurethane, polyacrylic and aldehyde resin, and alkyd resin) were applied onto the wood surfaces. The colours of the surfaces in the system, CIE L*a*b* (lightness, coordinates a* and b*, chroma and hue angle), were measured during finishing and natural ageing behind glass windows in an interior, over a period of 60 days. The results show that the changes in the yellowness index, and the total colour differences after the application of individual surface finishes to wood species, changed because of sunlight exposure. Moreover, it is clear that different wood finishes behaved differently on all of the wood species. An analysis is presented in this paper.

Effect of Wood Vinegar Substitutes on Acetic Acid for Coagulating Natural Para Rubber Sheets during the Drying Process

The coagulating properties of wood vinegar from para rubber wood, bamboo, and coconut shell used as a substitute for acetic acid in the production process of natural rubber (NR) sheets were investigated and considered. For the dirt and volatile content, the tensile strength at break, the percentage of elongation at break, and the 300% modulus, the results showed that the types of wood vinegar coagulants were not significantly different from acetic acid. However, the Mooney viscosity and plasticity retention index (PRI) properties were significantly different from those of acetic acid. The NR sheet temperature increased rapidly during the first hour after the drying process started due to heat transfer from the hot air. Afterward, the temperature of the NR sheet samples began to stabilize. When the drying process started, the drying temperature was increased, so the trend was reducing the drying time. For the yellowness index (YI) value, the increase in the YI value was related to the type of coagulating material, the increase in the airspeed, and the drying temperature. The dried sheet samples using para rubber wood vinegar as the coagulating material had a color value at the same level as acetic acid and the referent. However, the bamboo and coconut shell wood vinegars were at a lower level. In comparing the YI value data between the experimental results and prediction values, the second-degree model had a better fit in prediction than the zero-degree and first-degree models. This result was confirmed by the higher mean of the coefficient of determination. The dried sheet product coagulated by using wood vinegar had fungus growth prior to supplying it to the customer.

Photocurable Epoxy Acrylate Coatings Preparation by Dual Cationic and Radical Photocrosslinking

In this work, epoxy acrylate resin (EA) based on the industrial-grade bisphenol A-based epoxy resin (Ep6) and acrylic acid (AA) has been synthesized in order to develop hybrid resin comprising both epoxide group and reactive, terminal unsaturation. Obtained epoxy acrylate prepolymer was employed to formulate photocurable coating compositions containing, besides the EA binder, also cationic or radical photoinitiators. Hence, when cationic photoinitiators were applied, polyether-type polymer chains with pending acrylate groups were formed. In the case of free radical polymerization, epoxy acrylates certainly formed a polyacrylate backbone with pending epoxy groups. Owing to the presence of both epoxy and double carbon–carbon pendant groups, the reaction product exhibits photocrosslinking via two distinct mechanisms: (i) cationic ring-opening polymerization and (ii) free radical polymerization. Therefore, photopolymerization behavior of synthetized hybrid resin with various photoinitiators was determined via photo-differential scanning calorimetry (photo-DSC) and real-time infrared spectroscopy (RT-IR) methods, and properties of cured coatings were investigated. The performance of the following type of photoinitiators was tested in the cationic photopolymerization: diaryliodonium cations or triarylsulfonium cations, and the following type of photoinitiators were used to induce free radical photopolymerization: α-hydroxyketones, acylphosphine oxides, and their mixtures. Lastly, the basic physicomechanical properties of cured coatings, such as tack-free time, hardness, adhesion, gloss, and yellowness index, were evaluated. Some structural factors and parameters of cationic and radical photoinitiators and photopolymerization mechanisms affecting the epoxy acrylate hybrid coatings performance are discussed.