Postharvest quality indices of different durian clones at ripening stage and their volatile organic compounds

The aim of the present work was to characterize the quality of durians at consumptions stage. Seven clones of durian namely “Musang King”, “D24″, “D88″, “IOI”, “XO”, “Red Prawn” and “Black Thorn” were characterized based on their physiochemical properties. The organic acid contents, sugar compositions and β-carotene of durian clones were measured by high-performance liquid chromatographic (HPLC), while the volatile organic compounds (VOCs) were analyzed using headspace solid phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC MS). There were significant differences on all the postharvest parameters in the selected durian clones. “Black Thorn” having orange pulp yieled the highest β-carotene content (4.55 × 10−5 kg/kg FW). The dominant sugars in the pulp of all durian clones were dominated by sucrose followed by glucose and fructose. Sulfur- and ester-containing compounds were the predominant VOCs found. Principal component analysis (PCA) allowed for the grouping of different durian clones based on VOCs

Enhanced fungicidal efficacy on Ganoderma boninense by simultaneous co-delivery of hexaconazole and dazomet from their chitosan nanoparticles

The excessive use of fungicides may be of environmental and health concerns. Hence, to overcome this problem, chitosan as a controlled release matrix was used in this work to encapsulate the fungicide for the development of enhanced fungicide nanodelivery system. In this proposed study, dual-loaded fungicides (hexaconazole and dazomet) were simultaneously encapsulated into chitosan nanoparticles as an antifungal agent on Ganoderma boninense (G. boninense). In this work, we report the synthesis and characterization of the nanoparticles prepared using various concentrations of the crosslinking agent of sodium tripolyphosphate (TPP); 2.5, 5, 10, and 20 mg mL−1, which resulted in the nanoparticles of CHDEN2.5, CHDEN5, CHDEN10, and CHDEN20, respectively. The effect of TPP on the synthesized nanoparticle size revealed that an increase of TPP resulted in smaller particles, which in turn play a crucial role in controlling G. boninense growth. CHDEN20 shows the highest antifungal efficacy with the lowest half-maximal effective concentration (EC50) on G. boninense. The formulated nanocarrier system of fungicide aims to enhance the efficient delivery of the active ingredients to the target site, able to sustain in it for a longer time, and consequently improve the fungicide efficacy in combating the basal stem rot disease in oil palm

Detecting BSR-infected oil palm seedlings using thermal imaging technique

Basal Stem Rot (BSR) is the most destructive disease instigated by a white wood rotting fungus called Ganoderma boninense, which cause great economic setback in oil palm productivity. It attacks the basal stem of oil palm trees, causing them to slowly rot. It also affects the xylem tissues that eventually interrupt water transportation to the upper part of the oil palm, turning the leaves at the frond become yellow. This problem should be prevented during nursery stage by separating between healthy and BSR-infected seedling. Therefore, this study focuses on the potential use of thermal imaging for detecting BSR in oil palm at seedling. Thermal images of oil palm seedling from healthy and BSR-infected were captured and processed to extract several thermal properties of the seedling, i.e., maximum, minimum, mean, and standard deviation of pixel intensity value. These values were then undergone statistical analysis to identify its significant different in differentiating healthy and BSR-infected seedling. Several classification models were tested including Linear Discriminant Analysis (LDA), Quadratic Discriminant Analysis (QDA), Support Vector Machine (SVM) and k-Nearest Neighbour (kNN). Principal Component Analysis (PCA) was used to reduce the dimensionality of the dataset. The results demonstrated that the highest accuracy achieved at 80.0 % using SVM (fine gaussian) classification model with PC1 and PC3 as the input parameter. This summarizes the potential of thermal imaging in detecting BSR-infected oil palm trees at seedling stage

Proteomic analyses of Elaeis guineensis Jacq.(African Oil Palm) basal stem rot disease related to Ganoderma boninense / Leona Daniela Jeffery Daim

Ganoderma boninese is a basidiomycete fungal pathogen. It mainly attacks the roots of oil palms which will lead to the basal stem rot (BSR) disease. The oil palm industry suffers yearly crop losses that are attributed to the spread of this disease. To obtain a clearer picture of expression profiles of the ever changing global protein network in ganoderma infected plants, a gel-based proteomics approach was conducted using leaf tissues sampled from young palms. Leaf tissues were used for experimental analysis mainly because they were easier to sample than root tissues. Even though the mechanism of infection of this disease is through the root systems, early detection of the disease by source of leaves is an added advantage. This is because tissues could be sampled without wounding the roots, thus rendering them exposed to possible disease infection. Differential analysis of the leaf proteome revealed 116 protein spots that changed in abundance. Identification of these spots revealed proteins that changed in carbohydrate metabolism, cellular component, energy production, fatty acid biosynthesis, immunity and defence, nitrogen metabolism, protein metabolism, stress response, transport, and photosynthesis. Some of these changes were then validated using Western blots. In-depth literature reviews showed that proteins involved in immunity and defence, specifically peroxiredoxin, detoxify reactive oxygen species that are harmful to the plants: Proteinprotein interaction studies showed that peroxiredoxins interacted with a disease resistance protein. These results suggest the possibility of further investigation into disease resistance proteins in host-pathogen interactions. The results obtained from the proteomic analyses of leaf tissues from inoculated oil palms could be used as a tool in early detection of the BSR disease. Additional validation and further investigations into these proteins could improve our biological understanding towards this disease

Effect of freezing on minimally processed durian for long term storage

Exposing fruits to freezing temperature has been shown to successfully extend the shelf life and control the microbiological activity in the fruits. However, freezing could also lead to undesirable losses in the fruit quality. The present work was conducted to investigate the effect of frozen storage on physicochemical qualities and microbial contaminations of “MK” (Musang King) and “D24” durian pulp and paste for one year. During frozen storage, both durian pulp and paste lost 1 %–2 % of their weight along with an increase in pulp softening. Changes in color intensity during freezing storage shifted the golden yellow “MK” pulp to higher hº (lighter yellow) and this directly reduced the total carotenoids and ß-carotene contents in “MK”. Similarly, “D24” changed to pale yellow alongside reduction on L* and C* after one year frozen storage. Long term frozen storage in the present work also decreased the SSC and ascorbic acid contents for both durian pulp and paste. However, the pH and TA were not affected. “MK” and “D24” pulp showed lower microbial contamination than paste, with higher contaminations were observed in “D24”. These results showed that frozen storage could be used to preserve the quality of durians for less than one year of storage

Changes in the volatile profiles, organic acid contents, and sugar compositions of durian pulps during long-term frozen storage

Frozen storage was introduced to maintain the quality and prolong the shelf life of durian pulps. The aim of the present work was to evaluate the changes of organic acids, sugars, and volatile organic compounds (VOCs) in “Musang King” (“MK”) and “D24” pulps under long-term frozen storage. Organic acids in “MK” and “D24” only showed slight decrements, but sugar contents especially sucrose drastically decreased during 1 year frozen storage. Fructose and glucose in both durian pulps increased during the first half period of storage; this might be due to the conversion of sucrose to monosaccharides during storage. Freezing also caused the loss of some VOCs especially sulfur- and ester-containing VOCs in “MK” and “D24” pulps. These results indicated that the flavor losses in “MK” and “D24” were mostly related to the losses of ester-containing compounds rather than organic acids and sugar compositions following 1 year frozen storage

Preparation of chitosan–hexaconazole nanoparticles as fungicide nanodelivery system for combating Ganoderma disease in oil palm

Fungicide is used to control fungal disease by destroying and inhibiting the fungus or fungal spores that cause the disease. However, failure to deliver fungicide to the disease region leads to ineffectiveness in the disease control. Hence, in the present study, nanotechnology has enabled the fungicide active agents (hexaconazole) to be encapsulated into chitosan nanoparticles with the aim of developing a fungicide nanodelivery system that can transport them more effectively to the target cells (Ganoderma fungus). A pathogenic fungus, Ganoderma boninense (G. boninense), is destructive to oil palm whereby it can cause significant loss to oil palm plantations located in the Southeast Asian countries, especially Malaysia and Indonesia. In regard to this matter, a series of chitosan nanoparticles loaded with the fungicide, hexaconazole, was prepared using various concentrations of crosslinking agent sodium tripolyphosphate (TPP). The resulting particle size revealed that the increase of the TPP concentration produced smaller particles. In addition, the in vitro fungicide released at pH 5.5 demonstrated that the fungicide from the nanoparticles was released in a sustainable manner with a prolonged release time up to 86 h. On another note, the in vitro antifungal studies established that smaller particle size leads to lower half maximum effective concentration (EC50) value, which indicates higher antifungal activity against G. boninense

A potent antifungal agent for basal stem rot disease treatment in oil palms based on chitosan-dazomet nanoparticles

The use of nanotechnology could play a significant role in the agriculture sector, especially in the preparation of new-generation agronanochemicals. Currently, the economically important plant of Malaysia, the oil palm, faces the threat of a devastating disease which is particularly caused by a pathogenic fungus, Ganoderma boninense. For the development of an effective antifungal agent, a series of chitosan nanoparticles loaded with a fumigant, dazomet, were prepared using various concentrations of sodium tripolyphosphate (TPP)—2.5, 5, 10, and 20 mg/mL, abbreviated as CDEN2.5, CDEN5, CDEN10, and CDEN20, respectively. The effect of TPP as a crosslinking agent on the resulting particle size of the synthesized nanoparticles was investigated using a particle size analyzer and high-resolution transmission electron microscopy (HRTEM). Both methods confirmed that increasing the TPP concentration resulted in smaller particles. In addition, in vitro fumigant release at pH 5.5 showed that the release of the fumigant from the nanoparticles was of a sustained manner, with a prolonged release time up to 24 h. Furthermore, the relationship between the chitosan-dazomet nanoparticles and the in vitro antifungal activity against G. boninense was also explored, where the nanoparticles of the smallest size, CDEN20, gave the highest antifungal efficacy with the lowest half maximum effective concentration (EC50) value of 13.7 ± 1.76 ppb. This indicates that the smaller-sized agronanoparticles were more effective as an antifungal agent. The size can be altered, which plays a crucial role in combatting the Ganoderma disease. The agronanoparticles have controlled release properties and high antifungal efficacy on G. boninense, thus making them a promising candidate to be applied in the field for Ganoderma treatment

Phytotoxicity of chitosan-based agronanofungicides in the vegetative growth of oil palm seedling.

Although fungicides could be the best solution in combating fungal infections in crops, however, the phytotoxic level of fungicides to the crops should be tested first to ensure that it is safe for the crops. Moreover, nanocarrier systems of fungicides could play a significant role in the advancement of crop protection. For this reason, chitosan was chosen in the present study as a nanocarrier for fungicides of hexaconazole and/or dazomet in the development of a new generation of agronanofungicides with a high antifungal potent agent and no phytotoxic effect. Hence, the encapsulation of fungicides into the non-toxic biopolymer, chitosan was aims to reduce the phytotoxic level of fungicides. In the present study, the in vivo phytotoxicity of chitosan-fungicides nanoparticles on the physiological and vegetative growth of oil palm seedlings was evaluated in comparison to its pure fungicides as well as the conventional fungicides. The results revealed the formation of chitosan-fungicides nanoparticles could reduce the phytotoxic effect on oil palm seedlings compared to their counterparts, pure fungicides. The chitosan-fungicides nanoparticles were seen to greatly reduce the phytotoxic effect compared to the conventional fungicides with the same active ingredient

Preliminary Analysis of Lignocellulose Content and Monolignol Composition of Oil Palm Trunk from Two Different Genetic Backgrounds

A preliminary investigation of chemical and lignin composition was conducted from samples of oil palm trunk of two different genetic backgrounds. A significant difference in percent (%) of standing palms was noted for the two different genetic backgrounds after 24 years of planting. Given that these palms were planted in neighboring fields, the objective of this preliminary study was to compare the chemical composition, as well as the lignin composition of the two palm varieties. When comparing the two populations, significant differences were observed in the structural carbohydrate composition and the lignin composition. This research constitutes the first reporting on the pyrolysis-gas chromatography-mass spectrometer analysis of oil palm trunk lignin composition