Cashew Research Articles

Single and basal crop coefficients for estimation of water requirements of subtropical and tropical orchards and plantations with consideration of fraction of ground cover, height, and training system

AbstractThis paper provides an overview of the research carried out over the last 25 years on the FAO56 single and basal crop coefficients of subtropical and tropical orchards and plantations of cactus pear, dragon fruit, fig, jujube, passion fruit, pomegranate, cape gooseberry, cherimoya, guava, longan, lychee, mango, papaya, acerola, carambola, cashew, cacao, coffee, jaboticaba, jatropha, macadamia, açai palm, coconut, date palm, guayule, oil palm, peach palm, ramie and rubber tree. The main objective of this review is to update standard single crop coefficients (Kc) and basal crop coefficients (Kcb) and complete the Kc and Kcb values tabulated in FAO56. Kc is the ratio between the non-stressed crop evapotranspiration (ETc) and the grass reference evapotranspiration (ETo), and Kcb is the ratio between the crop transpiration (Tc) and the ETo. When selecting and analysing the literature, only studies that used the FAO Penman–Monteith equation, or another equation well related to the former to compute ETo were considered, while ETc or Tc were obtained from accurate field measurements on crops under pristine (non-stress cropping conditions) or eustress (“good stress”) conditions. Articles meeting these conditions were selected to provide data for updating Kc and Kcb under standard conditions. The related description of orchards and plantations refers to crop cultivar and rootstock, irrigation systems and scheduling, planting spacing, fraction of ground cover (fc) by the crops, crop height (h), crop age and training systems, as Kc and Kcb values depend on these characteristics. To define the standard Kc and Kcb values of the selected crops, the values collected in the literature were compared with previously tabulated standard Kc and Kcb values. The updated tabulated values are transferable to other locations and climates and can be used to calculate and model crop water requirements, primarily for irrigation planning and scheduling, and thereby supporting of improved water use and savings, which is the overall aim of the current review.

Larval diet of the carpenter bee Xylocopa (Neoxylocopa) cearensis (Hymenoptera: Apidae: Xylocopini) from Delta do Parnaíba Environmental Protection Area

The genus Xylocopa Latreille, 1802 (Apidae: Xylocopini) Latreille includes efficient pollinating bees that visit a wide range of botanical species. Although several studies have investigated their interactions with plants in dune ecosystems, there is still a limited understanding of these bee communities in coastal environments. This study aimed to characterize the larval diet of Xylocopa (Neoxylocopa) cearensis Ducke, 1910 by analyzing pollen from their nests to assess the presence of specialization or generalization in relation to botanical species. The research was carried out in coastal sandbanks of the Delta do Parnaíba Environmental Protection Area, Tutóia, Maranhão-BR, over a 12-month. The natural nests were inventoried by active searches and, when possible, transported to the Federal University of Maranhão. Pollen samples were collected from 19 brood cells of 12 nests in total. All the nests were found on branches of Anacardium occidentale L. Using the cetolysis method, 21 types of pollen were recognized, representing 14 botanical families. Three of those types of pollen were considered to be Frequent pollen, Mouriri cearensis Huber (35.44%), Chamaecrista ramosa (Vogel) H. S. Irwin & Barneby (32.80%) and Myrcia multiflora (Lam.) DC (27.05%). Based on these results, X. cearensis can be characterized as a polylectic species that demonstrates adaptability. These floral resources serve as essential protein sources for the nutrition of their brood, highlighting the importance of these plant species in supporting their reproductive success. This study provides useful information that can serve as a reference for future research on other Xylocopa species in similar ecosystems.

Cashew apple in Tanzania: status of utilization, challenges, and opportunities for sustainable development

Cashew apples, although widely available and rich in nutrients are still underutilized after harvest in Tanzania. Approximately 2,327,000 metric tonnes of cashew apples are lost each year. Their counterpart, the cashew nut is highly appreciated and successfully contributes to the national economy. The huge underutilization of cashew apples is a challenge that requires urgent attention in order to achieve both national and global Sustainable Development Goals (SDGs) by 2030. Improvement of the cashew apple sector could have a positive impact on global SDGs 1, 2, and 3 targets of no poverty, zero hunger, and good health and well-being respectively. At national level, this sector could contribute to the goals of the Tanzania Development Vision (TDV) 2025, namely: high quality livelihood, particularly food self-sufficiency and food security; and a strong and competitive economy, particularly a diversified and semi-industrialized economy with a substantial industrial sector comparable to typical middle-income countries. In addition, the country’s Third Five Year Development Plan III (FYDP III) 2021/22 – 2025/26 has established key strategic interventions, notably those related to competitive industrialization, energy, and food and nutrition security to ultimately achieve the goals of the TDV 2025. To be effective, however, these strategic interventions require continued strong central and local government support and active involvement of stakeholders to ensure program effectiveness yielded towards efficient utilization of widely available natural resources such as cashew apples which has cross-cutting benefits in food, agriculture, health, energy, and economic perspectives. Therefore, the work provides evidence on the utilization status, challenges, and opportunities for sustainable development in Tanzania.

Small size CNN (CAS-CNN), and modified MobileNetV2 (CAS-MODMOBNET) to identify cashew nut and fruit diseases

Small size CNN (CAS-CNN), and modified MobileNetV2 (CAS-MODMOBNET) to identify cashew nut and fruit diseases

Isolation of Cardanol Fractions from Cashew Nutshell Liquid (CNSL): A Sustainable Approach

Exploring sustainable approaches to replace petroleum-based chemicals is an ongoing challenge in reducing the carbon footprint. Due to the complexity and percentage variation in nature-generated molecules, which further varies based on geographical origin and the purification protocol adopted, a better isolation strategy for individual components is required. Agrowaste from the cashew industry generates phenolic lipid (cardanol)-rich cashew nutshell liquid (CNSL) and has recently shown extensive commercial utility. Cardanol naturally exists as a mixture of three structurally different components with C15-alkylene chains: monoene, diene, and triene. The separation of these three fractions has been a bottleneck and is crucial for certain structural designs and reproducibility. Herein, we describe the gram-scale purification of cardanol into each component using flash column chromatography within the sustainability framework. The solvent used for elution is recovered and reused after each stage (up to 82%), making it a cost-effective and sustainable purification strategy. This simple purification technique replaces the alternative high-temperature vacuum distillation, which requires substantial energy consumption and poses vacuum fluctuation and maintenance challenges. Three components (monoene 42%, diene 22%, and triene 36%) were isolated with good purity and were fully characterized by 1H and 13C NMR, GC-MS, HPLC, and FTIR spectroscopy. The present work demonstrates that greener and simpler strategies pave the way for the isolation of constituents from nature-sourced biochemicals and unleash the potential of CNSL-derived fractions for high-end applications.

Optimizing Activated Carbon Production from Waste Cashew Nut Shell with Zinc Chloride: A Box-Behnken Design and Group Method of Data Handling (GMDH) Application

In this study, Response surface methodology (RSM) and innovative Group Method of Data Handling (GMDH) approaches are applied to investigate the optimal process conditions of zinc chloride activated cashew nut production process. The effects of activation conditions (i.e. activation temperature, activation time, and impregnation ratio) on the achievable BET surface areas were studied with the aid of Box Behnken Design (BBD) and GMDH. Comparative analyses of RSM and GMDH-type neural models were further researched. During the process, the polynomial model equations developed were modified and fine-tuned to predict the highest BET surface area(s) using regression analysis and GMDH multi-layered iterative algorithm (MIA). Analysis of Variance (ANOVA) revealed that the significant factor(s) were impregnation ratio, impregnation ratio product, and the 2-way interactions (activation temperature and impregnation ratio) for ZnCl2 activated cashew nut shell. The best activation conditions for producing highest BET surface area of 504 m2.g-1 was activation temperature (873K), activation time (60 min), and impregnation ratio (1.50).The proposed GMDH-type BET model was ascertained to be the best model with average correlation coefficient (R) and root mean square error (RMSE) of 0.925 and 32.0 respectively. Sensitivity analysis conducted for GMDH-type neural network also revealed that the activation temperature and activation time with sensitivity values of 90.6% and 74.1% respectively were the most influential parameters in the basic (ZnCl2) activation process. The results of this study show that RSM and GMDH-type neural network could be applied as effective analytical tools for optimizing the ZCNS (zinc chloride-activated cashew nut shells) manufacturing process.

Selenium in plant-based beverages: How can in vitro bioaccessibility contribute to an accurate daily intake?

BackgroundLactose intolerance, cow milk protein allergy, and environmental and ethical concerns drive the global market for plant-based beverages (PPBs). Despite this, data on the occurrence of selenium (Se) in these beverages are scarce. ObjectiveThe objectives of this study were to assess total selenium and determine the bioaccessible fractions in plant-based beverages (PBBs) from cereals, oilseeds, and pumpkin seeds, using an in vitro static method to simulate human digestion; and estimate the contribution these beverages have to the reference daily intake (RDI) for children and adults. MethodologyThe study involved beverages made under laboratory conditions. Samples and extracts were submitted to acid digestion (ultrasonic and block digester); total and bioaccessible Se levels were determined by ICP-MS. In vitro bioaccessibility was assessed using the INFOGEST protocol. ResultsThe results revealed a wide variation in Se content in the studied plant-based beverages from 10.3 µg kg−1 (sunflower seeds) to 3509 µg kg−1 (Brazil nuts). The bioaccessibility of Se was found only in PBBs made from oilseeds with macadamia, cashew and Brazil nut, with a variation in values from 86 to 96 %. The Se content and its bioaccessible fraction of Brazil nut PBB may contribute to 1276 % and 1218 % of the RDI for children and adults, respectively. ConclusionsThe Se content varied among samples of cereals, oilseeds and pumpkin seeds, reflecting the diversity in the studied PBBs. Only PBBs containing oilseeds (macadamia, cashews, and Brazil nuts) exhibited measurable amounts of bioaccessible Se, indicating an association with the raw material. However, the consumption of the PBB containing Brazil nuts may pose a risk of adverse effects, due to its high contribution to the RDI in both children and adults.

Agronomic Performance of Young Cashew Trees Cultivated in Association with Groundnuts

Cultural association is widely practiced in rural areas by cashew nut producers. These producers typically cultivate annual plants between the rows of young cashew trees. However, there are interactions between these associated crops, which can either result in complementarity or competition among the plants for environmental resources such as water and nutrients. Consequently, young cashew seedlings newly planted were associated with groundnuts during their first two years. The aim of this study was to investigate the compatibility of the cashew/groundnut system. The results showed that there is competition between groundnuts and young cashew trees in the first year, leading to poor cashew growth in association. Nevertheless, from the second year onwards, cashew trees cultivated in association exhibited similar growth to those cultivated in monoculture. Therefore, it would be advisable to plant groundnut seeds sufficiently far from cashew tree seedlings to avoid potential competition in the first year of cultivation.

Identification, Characterization, Cloning, and Cross-Reactivity of Zan b 2, a Novel Pepper Allergen of 11S Legumin.

Protein from Sichuan peppers can elicit mild to severe allergic reactions. However, little is known about their allergenic proteins. We aimed to isolate, identify, clone, and characterize Sichuan pepper allergens and to determine its allergenicity and cross-reactivities. Sichuan pepper seed proteins were extracted and then analyzed by SDS-PAGE. Western blotting was performed with sera from Sichuan pepper-allergic individuals. Proteins of interest were purified using hydrophobic interaction chromatography and gel filtration and further analyzed by analytical ultracentrifugation, circular dichroism spectroscopy, and mass spectrometry (MS). Their coding region was amplified in the genome. IgE reactivity and cross-reactivity of allergens were evaluated by dot blot, enzyme-linked immunosorbent assay (ELISA), and competitive ELISA. Western blot showed IgE binding to a 55 kDa protein. This protein was homologous to the citrus proteins and has high stability and a sheet structure. Four DNA sequences were cloned. Six patients' sera (60%) showed specific IgE reactivity to this purified 11S protein, which was proved to have cross-reactivation with extracts of cashew nuts, pistachios, and citrus seeds. A novel allergen in Sichuan pepper seeds, Zan b 2, which belongs to the 11S globulin family, was isolated and identified. Its cross-reactivity with cashew nuts, pistachios, and citrus seeds was demonstrated.

Livelihoods Transformation and Climate Change Adaptation of the Ethnic Minorities: A Case Study of the Khmer People in Binh Phuoc Province, Vietnam

Typhoons, floods, and droughts brought on by climate change in Vietnam have severely damaged the livelihoods of farmers, particularly those of the Khmer people in Binh Phuoc province. In the Khmer community, drought has resulted in widespread crop deaths and livestock without food sources for more than ten years. Using qualitative data sources from in-depth interviews and participant observations in the community at several times in 2020, 2021, 2022, and 2023, the study aims to examine the Khmer community’s livelihood transformation to adapt to climate change. The findings show that, in response to extreme weather events, the community has changed crops from growing pepper and rice to drought-tolerant rubber, cashew, and fruit trees; they have also shifted their livestock from buffalo to goats and cows. Families with limited land for production have divided their resources to become workers and other secondary sources of income. This transformation shows how dynamically livelihoods are adapting to climate change while also helping the Khmer people become less vulnerable to weather-related shocks. The article also makes some suggestions for policy about the livelihoods of the Khmer people in relation to environmental challenges and climate change.

Precision allergy molecular diagnosis applications in food allergy.

Precision medicine has become important in the diagnosis and management of food allergies. This review summarizes the latest information regarding molecular allergology, an essential component of food allergy managements. Component-resolved diagnostics (CRD) can be used to investigate sensitization to allergens based on symptoms and to reveal co-sensitization and/or cross-sensitization in patients with allergies. The following allergen components are known to be associated with symptoms: ovomucoid from eggs, omega-5 gliadin from wheat, and many storage proteins (Gly m 8 from soy, Ara h 2 from peanut, Cor a 14 from hazelnut, Ana o 3 from cashew nut, Jug r 1 from walnut, and Ses i 1 from sesame). Recent studies on allergens of macadamia nuts (Mac i 1 and Mac i 2), almonds (Pru du 6), fish (parvalbumin and collagen), and shrimp (Pem m 1 and Pem m 14) have provided additional information regarding CRD. In addition, Pru p 7 is a risk factor for systemic reactions to peaches and has recently been found to cross-react with cypress and Japanese cedar pollen. CRD provides information of individualized sensitization profiles related to symptoms and severity of allergies in patients. Clinical practice based on CRD offers many benefits, such as higher diagnostic accuracy and improved management of individual patients.

Evaluation of fruit detachment forces and related characteristics reveals differential fruit detachments at developmental stages and cultivar differences in cashew

Cashew is an edible tree nut with great nutritional and industrial importance. Cashew fruit is unique because the true fruit (nut) grows attached to a swollen flower pedicel known as a hypocarp or cashew apple. The fruit detachment force (FDF), a quantitative measurement of the detachment of fruits from the stalk, is considered as an important parameter for the evaluation of the harvesting efficiency of machines, and the cultivar's potential for machine harvesting, and tolerances to biotic and abiotic stresses. There have been no studies on the evaluation of FDFs in cashew to date. In the current study, we investigated the detachment forces of fruits at ten different stages of development according to the BBCH (Biologische Bundesanstalt, Bundessortenamt und Chemische Industrie) scale, a uniform coding system for different growth or phenological stages (701, 703, 705, 707, 709, 811, 813, 815, 817, 819) in ten cashew cultivars. Fruit weight (FW), FDF/FW ratio, and fruit firmness (FF) for different fruit development stages and fruit stalk scar area (SSA) of matured (819 stage) fruits were also studied. FDF, FW, FDW/FW and FF varied significantly at the different stages of fruit development among the studied cultivars. The FDF increased from 701 to 709 stages and then decreased from 709 to 819 stages in all the studied cultivars. The FDW/FW ratio reduced with the development and maturity of the fruit. In matured fruits (811–819 stages), FW and FF showed significant negative (p value = 0.028) and positive (p value = 0.015.) correlations, respectively, with the FDF. In contrast, the SSA had no significant influence on the FDFs. As the FDF has direct implications on the fruit removal efficiency, the results of this study will be useful for designing harvesting machines, screening genotypes for stress tolerance, and identifying the optimal harvesting stage in cashew.

Card-bisphenol based bio-silica reinforced poly(urethane-co-benzoxazine) foam for an electrical insulation

Agricultural waste by-products such as cashew nut shell liquid and rice husk ash were utilized for the syntheses of card-bisphenol (C) and precipitated bio-silica (S), respectively. A hydroxyl terminated card-bisphenol based benzoxazine resin (CHB) was synthesized and then converted it into soft-foam namely benzoxazine-co-urethane pre-polymer (CHB-UF) by polymerizing with hexamethylene diisocyanate (HMDI) in the absence of any catalysts or foaming agents. Subsequent thermal ring opening polymerization of CHB-UF at 200 °C provides poly(benzoxazine-co-urethane) hard-foam (PCHB-UF) with little shrinkage. Similarly, different weight ratios of precipitated bio-silica (0–15 wt%) reinforced bio-based PCHB-UF hard-foam composites (PCHB-UFS) were prepared to utilize them for high-k dielectrics and hydrophobic applications. The foam microstructure was ascertained through the field emission scanning electron microscopy (FE-SEM). The reinforcement of bio-silica into the CHB-UF foam increases the value of dielectric constant according to the increase in weight percentage concentration, which might be due to the reduction in volume of voids. The neat PCHB-UF possesses the value of dielectric constant of 7.04 with lower value of dielectric loss of 0.01. Similarly, the values of dielectric constant and dielectric loss of 15 wt% bio-silica reinforced composites (PCHB-UFS15) are 10.1 and 0.08 respectively. The PCHB-UFS15 has shown hydrophobic nature with the value of water contact angle of 135°. Data obtained from different studies suggest that the bio-foam composites obtained from sustainable sources can be considered as an efficient dielectric materials used for electronics insulation.

A case of a one-year-old girl with cashew nut allergy diagnosed as pectin allergy based on anaphylaxis after ingestion of fruit gummies

A case of a one-year-old girl with cashew nut allergy diagnosed as pectin allergy based on anaphylaxis after ingestion of fruit gummies

Assessment of farmers’ knowledge on the foliar fertilizer use for improved cashew (Anacardium occidentale L) productivity in south-eastern Tanzania

Purposethe study aim was to evaluate the farmers' knowledge on fertilizer use in cashew by assessing their awareness on the fertilizers, extent of use, obtained benefits from use in cashew, limiting factors of use, availability and changes after use. Cashew (Anacardium occidentale L) is a recent topmost strategic crop in Tanzania. Through cashew, earnings of > $585 million were reached in 2017/18 season. Chlorosis, flower abortion and dropping of immature nuts hinder cashew production referring the decrease from 3200,000 Metric Tons (MT) in 2017/18 to less than 200,000 MT in 2021/2022. Farmers’ knowledge on fertilizer use in cashew is not precisely known. Methodsthrough cross-section design using questionnaires, purposive sampling of respondents was done. Four villages each from three agro-ecologies i. e, Makonde Plateau (MP), Tunduru Dissected Plains (TDP), and Masasi-Nachingwea Plains (MNP) were selected in South-eastern, Tanzania. About 480 households were interviewed. Resultsabout 75% of respondents were aware of foliage fertilizers while 45.4% agreed on their suitability for cashew. About 44.7%, 27.9%, and 27.4% of respondents use foliar fertilizers in TDP, MP, and MNP, respectively. Some respondents (3.7%) apply 1 L of foliage fertilizers per round acre−1 and 5.1% apply for 1–3 rounds, and some few (1%) apply up to 10 rounds season−1. Cashew farming experience and credit access negatively influenced foliar fertilizer uses; hence foliar fertilizer prices linearly reduced the extent of use. Conclusionlimited knowledge among the farmers on fertilizer use in cashew was a challenge. Therefore, farmers' training and detailed fertilizer use research are recommended.

Valorizing cashew nutshell residue for sustainable lignocellulosic panels using a bio-based phenolic resin as a circular economy solution

The motivation for this study stems from the significant annual amount of cashew nutshells produced worldwide, which has raised growing concerns about proper environmental disposal. One alternative is to utilize the nutshells to produce particleboards and eco-friendly resin, thereby contributing to the circular economy. The present study proposes an innovation by providing the first insights into particleboard production, utilizing pressed cashew nutshell and a phenolic resin derived from the reaction of cashew nutshell liquid (CNSL) with formaldehyde. The mass proportions of CNSL to formaldehyde were varied at 1:0.25, 1:0.5, and 1:0.75 (w/w) without the necessity for isolating chemical compounds at 105 °C. The resin was characterized using rheology, DSC, FTIR, HPLC, and NMR techniques. The mechanical properties of the particleboard were evaluated through density, tensile, flexural, water absorption, and thickness swelling tests. The formaldehyde emission and biodegradability content of the particleboards were also evaluated. Eco-friendly phenol-formaldehyde resin promoted the modulus of elasticity (MOE) from 707 to 1866 MPa and the modulus of rupture (MOR) from 6.4 to 14.3 MPa. In addition, using adhesive with CNSL to formaldehyde mass ratios of 1:0.25 and 1:0.50 resulted in particleboards of class E1 in terms of formaldehyde emissions. The biodegradability of panels PB25, PB50 and PB75 was 30%, 21% and 20%, respectively, in 30 days. These findings demonstrate the potential of cashew nutshell biomass and eco-friendly resin as an adhesive in the particleboard industry.

Vertical coordination in agri‐food supply chain and blockchain: A proposed framework solution for Vietnamese cashew nut business

The agri‐food supply chain has been a popular research topic in recent years. The combination of a demand for products of high quality and safety standards and the increasing number of stakeholders in supply chain networks has required the agri‐food business to transform from vertically integrated to vertically operated supply chain networks. Nevertheless, this traditional agri‐food supply chain form has exposure to some drawbacks. Meanwhile, blockchain technology as a disruptive technology today has the potential to provide value‐added contributions towards multiple‐disciplinary applications. Blockchain technology gains success and proves its functionality in improving the current supply chain by ensuring traceability, transparency and efficiency across the network from farmer to consumer. Therefore, the purpose of this paper is to review the existing literature on vertical coordination in the supply chain and its mechanism and to develop a framework that explores how blockchain technology can address the challenges in coordination mechanisms. Furthermore, taking the current Vietnamese vertical coordination cashew supply chain as a case study, this research is based on the proposed framework to suggest a solution combining blockchain and other relative technologies for the Vietnamese cashew business. This paper will close a research gap, as the blockchain‐based supply chain for Vietnam cashew nuts has potential benefits for each supply chain actor in terms of effectiveness in operations, costs and time‐saving, and human resources.

A Novel Cardanol-Based Monoglyceride Using Cashew Nut Shell Liquid

Phenol is a widely used non-renewable petrochemical resource in many organic syntheses, hence sourcing phenolic derivatives from renewable resources is an important concern. In this study, a novel monoglyceride (MG) was synthesized utilizing “cardanol” as a starting material, which is an eco-friendly and natural phenolic derivative. Cardanol was obtained by the decarboxylation of anacardic acid present in raw cashew nut shell liquid (CNSL). It was then reacted with maleic anhydride (MA) to synthesize a novel mono-phenyl maleate (MPM) derivative with a purity of 65.5%. This product was subjected to a direct esterification with glycerol to obtain the novel MG. Based on the per-iodic oxidation method, the percentage composition of the monoglyceride was obtained to be 70.1%. It showed high thermal stability up to 250 ℃. This MG being a thermally stable di-functional compound makes it a potential novel monomer that can be used to synthesize novel alkyd resins with enhanced properties in the future.

A Low-Cost Deep-Learning-Based System for Grading Cashew Nuts

Most of the cashew nuts in the world are produced in the developing countries. Hence, there is a need to have a low-cost system to automatically grade cashew nuts, especially in small-scale farms, to improve mechanization and automation in agriculture, helping reduce the price of the products. To address this issue, in this work we first propose a low-cost grading system for cashew nuts by using the off-the-shelf equipment. The most important but complicated part of the system is its “eye”, which is required to detect and classify the nuts into different grades. To this end, we propose to exploit advantages of both the YOLOv8 and Transformer models and combine them in one single model. More specifically, we develop a module called SC3T that can be employed to integrate into the backbone of the YOLOv8 architecture. In the SC3T module, a Transformer block is dexterously integrated into along with the C3TR module. More importantly, the classifier is not only efficient but also compact, which can be implemented in an embedded device of our developed cashew nut grading system. The proposed classifier, called the YOLOv8–Transformer model, can enable our developed grading system, through a low-cost camera, to correctly detect and accurately classify the cashew nuts into four quality grades. In our grading system, we also developed an actuation mechanism to efficiently sort the nuts according to the classification results, getting the products ready for packaging. To verify the effectiveness of the proposed classifier, we collected a dataset from our sorting system, and trained and tested the model. The obtained results demonstrate that our proposed approach outperforms all the baseline methods given the collected image data.

Pyrolysis of cashew nut shells-focus on extractives

Cashew nut shells (CNS), as non-edible agricultural residues produced by cashew nut shelling units, are largely abundant in West Africa. They present a strong potential for energy production although the presence of specific extractives known collectively as cashew nut shell liquid (CNSL) is problematic. These extractives can account for up to 40 % of the mass of the shells and are mainly composed of anacardic acids, cardanols and cardols (ACC). The objective of this work was to study the influence of ACC constituents on the pyrolysis of CNS. To this end, an exhaustive characterization of CNS was performed, followed by a series of pyrolysis experiments on CNS, extractives and solid residues. Thermogravimetric analyses revealed intermolecular interactions between the lignocellulosic solid matrix and the extractives of CNS. Experiments carried out in a fixed bed reactor enabled determination of pyrolysis products composition. Only cardanols were present in both CNS and ACC pyrolysis condensates. The degradation of anacardic acids during ACC pyrolysis at 400 °C was investigated and showed that 45 % of anacardic acids produce cardanols as end products, whereas the remaining anacardic acids form thermal cracking products (char, gas and condensates). The distribution of the end products of CNS pyrolysis is illustrated in the graphical abstract.