Phenolic compounds from macadamia husk: An updated focused review of extraction methodologies and antioxidant activities
This review explores the potential of agri-food waste materials, with a particular focus on macadamia nut by-products. Industrial processing of macadamia nuts yields a significant volume of by-products, including green husk and woody shell. Recent research has highlighted these by-products as readily available, cost-effective rich sources of phenolic compounds, renowned for their potent antioxidant and antibacterial properties. This paper emphasizes the importance of selecting an optimal extraction method to fully harness the bioactive potential of these phenolic compounds. In this work, we provide a comprehensive overview of conventional and advanced extraction techniques that are used to extract phenolic compounds from macadamia by-products, with a particular focus on the methods applied to macadamia green husk. Among the various techniques, it appears that ultrasound-assisted extraction, especially when combined with aqueous organic solvents, is more efficient than other methods for this purpose. This review also addresses the challenges in phenolic compound recovery, primarily due to the lack of a standardized extraction process. This often results in the extensive use of extraction solvents to achieve an extract that is rich in phenolic compounds. Overall, this research offers a valuable understanding of the most effective methods for the extraction and recovery of phenolic compounds from macadamia by-products and discusses the potential for scaling up these extraction processes. Hence, it can serve as a useful resource for researchers and industry professionals interested in sustainable and efficient utilization of by-products of the nut industry. https://doi.org/10.1016/j.fbp.2024.09.014
Cashew Nut Shell Waste Derived Graphene Oxide
The particular properties of graphene oxide (GO) make it a material with great technological potential, so it is of great interest to find renewable and eco-friendly sources to satisfy its future demand sustainably. Recently, agricultural waste has been identified as a potential raw material source for producing carbonaceous materials. This study explores the potential of cashew nut shell (CNS), a typically discarded by-product, as a renewable source for graphene oxide synthesis. Initially, deoiled cashew nut shells (DCNS) were submitted to pyrolysis to produce a carbonaceous material (Py-DCNS), with process optimization conducted through response surface methodology. Optimal conditions were identified as a pyrolysis temperature of 950 °C and a time of 1.8 h, yielding 29.09% Py-DCNS with an estimated purity of 82.55%, which increased to 91.9% post-washing. Using a modified Hummers method, the Py-DCNS was subsequently transformed into graphene oxide (GO-DCNS). Structural and functional analyses were carried out using FTIR spectroscopy, revealing the successful generation of GO-DCNS with characteristic oxygen-containing functional groups. Raman spectroscopy confirmed the formation of defects and layer separations in GO-DCNS compared to Py-DCNS, indicative of effective oxidation. The thermogravimetric analysis demonstrated distinct thermal decomposition stages for GO-DCNS, aligning with the expected behavior for graphene oxide. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) further corroborated the morphological and compositional transformation from DCNS to GO-DCNS, showcasing reduced particle size, increased porosity, and significant oxygen functional groups. The results underscore the viability of cashew nut shells as a sustainable precursor for graphene oxide production, offering an environmentally friendly alternative to conventional methods. This innovative approach addresses the waste management issue associated with cashew nut shells and contributes to developing high-value carbon materials with broad technological applications. https://doi.org/10.3390/molecules29174168
Improved Straw Decomposition Products Promote Peanut Growth by Changing Soil Chemical Properties and Microbial Diversity
The ameliorative effects of straw decomposition products on soil acidification have been extensively studied. However, the impact of chemically treated straw decomposition products on crop productivity and the underlying microbial mechanisms remain unclear. This study aimed to investigate the effects of two dosages of Ca(OH)2-treated straw decomposition products of peanuts on red soil acidity, fertility, and bacterial and fungal diversity through a pot experiment. The pot experiment included four treatments: chemical nitrogen, phosphorus, and potassium (NPK) fertilization alone (CK), NPK chemical fertilization combined with peanut straw decomposition products (PS), NPK chemical fertilization combined with 4% Ca(OH)2-treated peanut straw decomposition products (PS4Ca), and NPK chemical fertilization combined with 8% Ca(OH)2-treated straw decomposition products (PS8Ca). High-throughput sequencing was performed to investigate the effects of these treatments on soil microbial diversity. The treatments with PS, PS4Ca, and PS8Ca significantly increased soil pH, exchangeable base cations, and nutrient content, whereas they decreased the exchangeable acid, especially exchangeable aluminum. The peanut growth improved substantially with the application of straw decomposition products. Specifically, PS4Ca significantly increased the Shannon and Richness indices of fungi. The principal coordinate analysis showed that the soil microbial communities in the straw decomposition product treatments were significantly different from CK. Linear discriminant analysis effect size identified unique bacteria and fungi between treatments. The Mantel test indicated that exchangeable base cations and pH were significantly positively correlated with bacterial communities, whereas available potassium was positively correlated with fungal communities. The partial least squares path modeling revealed that the bacterial communities positively and directly affected all peanut agronomic traits. In contrast, the fungal communities had a negative and direct effect only on peanut 100-pod weight. Therefore, adding Ca(OH)2-treated straw decomposition products could effectively improve crop productivity by alleviating soil acidification, increasing soil nutrients, and subsequently changing microorganisms.
https://doi.org/10.3390/su16167096
The Effects of Land Fragmentation on Hazelnut Farming in Türkiye: Environmental, Economic, and Policy Perspectives
Land fragmentation is a critical problem that threatens the economic and environmental sustainability of hazelnut farms. The aim of the study was to assess the economic and environmental effects of land fragmentation on hazelnut farming in Türkiye. The primary data for the study were collected through face-to-face questionnaires from 121 randomly sampled hazelnut farms. The partial budgeting analysis method was used to estimate the economic performance of the hazelnut farms. The environmental impact of land fragmentation in hazelnut farming was assessed using the life cycle assessment (LCA) method. The study revealed that the average production cost per hectare was US$ 1834.0 in fragmented farms, compared to US$ 1661.2 in non-fragmented farms. The hazelnut production cost per kilogram in the fragmented farms was 20.18% higher than in non-fragmented farms. The higher share of variable costs in the total production costs of fragmented farms was due to increased hired labor costs. Economic performance indicators, including GDP, gross profit, net profit, and relative profit, were lower in fragmented farms compared to non-fragmented farms. The LCA results showed that hazelnut production emitted 618.60 kg of CO2-eq of greenhouse gas (GHG) per hectare in 1 year. Additionally, producing 1 kg of hazelnuts emitted 0.4495 kg CO2-eq of GHG emissions. For non-fragmented farms, the GHG emissions per kilogram of hazelnuts were 0.4780 kg CO2-eq, while in fragmented farms, it was 0.5342 kg CO2-eq. This represented an 11.74% increase in GHG emissions for fragmented farms. The significantly lower GHG emissions in non-fragmented farms were mainly due to differences in chemical fertilization and farm manure application. In contrast, fragmented farms showed a larger machinery-related contribution and a more pronounced impact of diesel usage on emissions. The study concluded that addressing land fragmentation on hazelnut farms would enhance their economic performance. GHG emissions can be mitigated by improving agricultural practices, optimizing machinery and fuel use, enhancing chemical management, reevaluating farm structures, and raising climate change awareness.
https://doi.org/10.1007/s10341-024-01178-6
Experimental Comparison of Open Sun and Indirect Convection Solar Drying Methods for Apricots in Uzbekistan
Solar drying is an environmentally friendly and sustainable approach to preserve agricultural products, particularly in regions with abundant sunlight. In terms of apricot cultivation, the implementation of solar drying methods can significantly impact post-harvest handling and storage. In the conditions of Uzbekistan, the drying of apricot products in indirect solar dryers is the next stage of development. This research aims to investigate the effectiveness of solar drying techniques for apricots in Uzbekistan, focusing on optimizing drying parameters and assessing the quality of the dried products. This study involves the design and implementation of solar drying systems for apricots. It primarily focuses on comparing and evaluating the drying times of apricots, changes in product moisture, and alterations in apricot color during the drying process using an Open Sun Dryer (OSD) and an Indirect Natural Convection Solar Dryer (INCSD). Various drying parameters such as the temperature, humidity, and drying time are monitored and controlled during the experiment. Additionally, the quality of the dried apricots is evaluated through analyses of their color, texture, and nutrient retention. According to the results, when apricots were dried in a solar dryer at 55 °C and with 35% humidity outside, their moisture content decreased from 85–90% to 12–18% within 15 h. The solar radiation intensity and ambient temperature play a crucial role in the acceleration of the time in the drying process. In general, utilizing equipment-based solar drying methods for apricots in Uzbekistan has the potential to rival traditional drying systems in terms of both quality and drying duration.
https://doi.org/10.3390/engproc2024067026
Resistance of pistachio grafted on different Pistacia rootstocks against Verticillium wilt under field conditions
Verticillium wilt of pistachio (Pistacia vera), caused by Verticillium dahliae, is one of the most important diseases in this crop. The most effective and economical control measure is the use of resistant rootstocks. The main objective of this work was to evaluate the resistance of five rootstocks commonly used in pistachio against the disease under field conditions. Pistachio plants (cv. Kerman) grafted on the rootstocks Pistacia atlantica, Pistacia integerrima, Pistacia terebinthus and cv. Platinum and UCBI hybrids, were planted in a field with high inoculum density of V. dahliae in the soil. Plants grafted on P. terebinthus, followed by P. integerrima, showed significantly higher disease severity values than the rest of the rootstocks almost 53 months after planting; also, plants grafted on P. atlantica were more resistant than those grafted on P. integerrima. These results highlighted the intraspecific variability in resistance to the disease. In addition, the disease was monitored in pistachios grafted onto P. terebinthus or UCBI in an established commercial field with three different zones of V. dahliae inoculum density in the soil (none, low or high). In the high-density zone, the percentage of diseased plants was significantly lower for plants grafted on UCBI than for those grafted on P. terebinthus. The results indicate the importance of rootstock species and specific genotype or seed population used, concentration of V. dahliae inoculum in the soil, and previous history of crops on the plot, on the development of the disease under natural conditions.
https://doi.org/10.1111/ppa.13978
Dendrochronological Analysis of Pinus pinea in Central Chile and South Spain for Sustainable Forest Management
Pinus pinea is an important Mediterranean species due to its adaptability and tolerance to aridity and its high-quality pine nuts. Different forest types located in Mediterranean native and non-native environments provide the opportunity to perform comparative studies on the species’ response to climate change. The aims of this study were to elucidate growth patterns of the species growing in native and exotic habitats and to analyze its response to climatic fluctuations, particularly drought, in both geographical contexts. Understanding stone pine (Pinus pinea) growth responses to climate variability in native and exotic habitats by comparing natural stands and plantations may provide useful information to plan adequate management under climate change. By doing so, we enhance the understanding of P. pinea’s adaptability and provide practical approaches to its sustainable management. In this study, we reconstructed and compared the stem radial growth of seven stone pine stands, two in southern Spain and five in central–southern Chile, growing under different climatic conditions. We quantified the relationships between growth variability and climate variables (total rainfall, mean temperature, and SPEI drought index). Growth was positively correlated with autumn rainfall in plantations and with autumn–winter rainfall in natural stands. Growth was also enhanced by high autumn-to-spring rainfall in the driest Chilean plantation, whereas in the wettest and coolest plantation, such correlation was found in winter and summer. A negative impact of summer temperature was found only in one of the five Chilean plantations and in a Spanish site. The correlation between SPEI and tree-ring width indices showed different patterns between and within countries. Overall, exotic plantations showed lower sensitivity to climate variability than native stands. Therefore, stone pine plantations may be useful to assist in mitigating climate change.
https://doi.org/10.3390/biology13080628
Enhancing nutritional status, growth, and fruit quality of dried figs using organic fertilizers in rain-fed orchards: A case study in Estahban, Iran
The majority of Iranian fig production is exported, making it one of the world's most well-known healthy crops. Therefore, the main objective of the current experiment was to investigate the effects of various types of organic fertilizers, such as animal manure (cow and sheep), bird manure (partridge, turkey, quail, and chicken), and vermicompost, on the nutritional status of trees, vegetative and reproductive tree characteristics, fruit yield, and fruit quality traits in dried fig cultivar ("Sabz"). According to the findings, applying organic fertilizers, particularly turkey and quail, significantly improves vegetative and reproductive characteristics. However, other manures such as sheep, chicken, and vermicompost had a similar effect on the growth parameters of fig trees. Additionally, the findings indicated that except for potassium, use of all organic fertilizers had an impact on macro and microelements such as phosphorus, nitrogen, and sodium amount in fig tree leaves. Also, based on fruit color analysis in dried figs, the use of all organic fertilizers improved fruit color. Moreover, the analyses fruit biochemical showed that the use of some organic fertilizers improved that TSS and polyphenol compounds such as coumarin, vanillin, hesperidin gallic acid and trans frolic acid. In general, the results indicated that the addition of organic fertilizers, especially turkey manure, led to increased vegetative productivity and improvement in the fruit quality of the rain-fed fig orchard.
https://doi.org/10.1371/journal.pone.0300615
Intercropping Systems: An Opportunity for Environment Conservation within Nut Production
Global population growth and intensive agriculture have both contributed negatively to the environment. As a result, there is increasing interest in the use of sustainable alternatives is increasing to promote better use of natural resources and create an equilibrium between agriculture and the environment. Intercropping, the simultaneous cultivation of multiple crops, aims to optimize land use economically while enhancing biodiversity through plant–microorganism interactions, thereby boosting crop productivity. This practice has particularly benefited nut production by combining the nutrient-sequestering capacity of trees with continuous annual crop production, improving soil nutrient and water utilization. Intercropping systems not only enhance nut yield and quality but also offer economic advantages to farmers. This review synthesized the existing literature with the aim of highlighting not only the positive aspects that intercropping brings to the production of nuts, but also the challenges and limitations faced in different regions when it comes to agricultural production. https://doi.org/10.3390/agriculture14071149
Exploring the bioactive potential of dried fruit by-products: a focus on hazelnut, peanut, and almond teguments and shells
Dried fruits are renowned for their nutritional value, particularly their seeds. However, their skins, shells, and hulls also hold significant nutritional and commercial potential, yet remain largely unexplored for their bioactive compounds. This study examines the teguments and shells of three types of dried fruits – hazelnut, peanut, and two almond varieties. Ethanol extracts from these by-products reveal a variety of phytochemicals with antioxidant, antimicrobial, anti-inflammatory, and antiviral properties, confirmed through in vitro and in vivo assays. Teguments contain higher polyphenol levels compared to shells, with 24 compounds identified via HPLC analysis. The Achak almond tegument extract demonstrates strong antiradical activity, significant antimicrobial effects, and notable antiviral properties at a low concentration. Moreover, extracts from Achak almond tegument and hazelnut shells exhibit notable anti-inflammatory properties. This underscores the potential of utilizing dried fruit by-products to create innovative, value-added products, supporting environmental sustainability and boosting the competitiveness of the dried fruit industry. https://doi.org/10.1080/09603123.2024.2373174