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Macadamia nuts are one of the most important economic food items in the world. Pericarp thickness and flavonoid composition are the key quality traits of Macadamia nuts, but the underlying mechanism of pericarp formation is still unknown. In this study, three varieties with significantly different pericarp thicknesses, namely, A38, Guire No.1, and HAES 900, at the same stage of maturity, were used for transcriptome analysis, and the results showed that there were significant differences in their gene expression profile. A total of 3837 new genes were discovered, of which 1532 were functionally annotated. The GO, COG, and KEGG analysis showed that the main categories in which there were significant differences were flavonoid biosynthesis, phenylpropanoid biosynthesis, and the cutin, suberine, and wax biosynthesis pathways. Furthermore, 63 MiMYB transcription factors were identified, and 56 R2R3-MYB transcription factors were clustered into different subgroups compared with those in Arabidopsis R2R3-MYB. Among them, the S4, S6, and S7 subgroups were involved in flavonoid biosynthesis and pericarp formation. A total of 14 MiMYBs' gene expression were verified by RT-qPCR analysis. These results provide fundamental knowledge of the pericarp formation regulatory mechanism in macadamia nuts.

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Cases of macadamia nut-induced anaphylactic shock have been rarely reported. We report the case of a three-year-old girl with anaphylactic shock who presented with generalized erythema two hours after ingesting macadamia nuts. She required two doses of intramuscular adrenaline for the treatment of anaphylactic shock. The diagnosis of macadamia nut allergy was confirmed by a prick-by-prick skin test using roasted and raw macadamia nut paste extracts and elevated serum macadamia nut-specific immunoglobulin E (IgE) levels. Appropriately using a prick-by-prick test may contribute to accurately diagnosing macadamia nut allergy, thus preventing the unnecessary avoidance of other nuts. Considering the potential for severe shock induced by macadamia nut allergy, vigilant monitoring of blood pressure changes is imperative in children presenting with immediate-type allergic reactions, such as vomiting and skin symptoms, following macadamia nut ingestion.

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The consumption of macadamia nuts has increased due to their cardioprotective and antioxidant properties. However, this rise is consistent with an increase in the cases of macadamia nut allergy, leading to severe reactions. Although two Macadamia integrifolia allergens (Mac i 1 and Mac i 2) have been identified in Australian and Japanese patients, the allergenic sensitization patterns in Western European populations, particularly in Spain, remain unclear. For this purpose, seven patients with macadamia nut allergy were recruited in Spain. Macadamia nut protein extracts were prepared and, together with hazelnut and walnut extracts, were used in Western blot and inhibition assays. IgE-reactive proteins were identified using MALDI-TOF/TOF mass spectrometry (MS). Immunoblotting assays revealed various IgE-binding proteins in macadamia nut extracts. Mass spectrometry identified three new allergens: an oleosin, a pectin acetylesterase, and an aspartyl protease. Cross-reactivity studies showed that hazelnut extract but not walnut extract inhibited macadamia nut oleosin-specific IgE binding. This suggests that oleosin could be used as marker for macadamia-hazelnut cross-reactivity. The results show an allergenic profile in the Spanish cohort different from that previously detected in Australian and Japanese populations. The distinct sensitization profiles observed highlight the potential influence of dietary habits and environmental factors exposure on allergenicity.

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The aim of the study was to explore the impact of both the macronutrient composition and snacking timing on the postprandial glycemic insulinemic responses and food intake. Seventeen healthy female volunteers completed the randomized crossover trials. The volunteers were provided a standard breakfast and lunch at 8:00 and 13:00, respectively, and an ad libitum dinner at 18:00. Provided at either 10:30 (midmorning) or 12:30 (preload), the glycemic effects of the three types of 70 kcal snacks, including chicken breast (mid-C and pre-C), apple (mid-A and pre-A), and macadamia nut (mid-M and pre-M), were compared with the non-snack control (CON), evaluated by continuous glucose monitoring (CGM). The mid-M showed increased insulin resistance after lunch compared with CON, while the pre-M did not. The pre-A stabilized the glycemic response in terms of all variability parameters after lunch, while the mid-A had no significant effect on postprandial glucose control. Both the mid-C and pre-C improved the total area under the glucose curve, all glycemic variability parameters, and the insulin resistance within 2 h after lunch compared with CON. The pre-C attained the lowest energy intake at dinner, while the mid-A and the mid-M resulted in the highest. In conclusion, the chicken breast snack effectively stabilized postprandial glycemic excursion and reduced insulin resistance while the macadamia snack did not, regardless of ingestion time. Only as a preload could the apple snack mitigate the glucose response after the subsequent meal.

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Global food waste emits substantial quantities of nitrogen to the environment (6.3 Mtons annually), chicken feather (CF) waste is a major contributor to this. Pyrolysis, in particular co-pyrolysis of nitrogen-rich and lignocellulosic waste streams is a promising strategy to improve the extent of pyrolytic nitrogen retention by incorporating nitrogen in its solid biochar structure. As such, this biochar can serve as a precursor for nitrogen-enriched activated carbons for application in supercapacitors. Therefore, this study investigates the co-pyrolysis of CF with macadamia nut shells (MNS) to create nitrogen-rich activated carbons. Co-pyrolysis increased nitrogen retention during pyrolysis from 9 % to 18 % compared to CF mono-pyrolysis, while the porosity was maintained. After removing undesirable inorganic impurities by dilute acid washing, this led to a specific capacitance of 21F/g using a scan rate of 20 mV/s. Finally, cycling stability tests demonstrated good stability with 73 % capacitance retention after 10 000 cycles.

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This study aims to examine the ameliorative effect of macadamia nut protein peptides (MPP) on acetaminophen (APAP)-induced liver injury (AILI) in mice, and develop a new strategy for identifying hepatoprotective functional foods. The molecular weight distribution and amino acid composition of MPP were first studied. Forty mice were then randomized into four groups: control group (CON), APAP model group, APAP+MPP low-dose group (APAP+L-MPP), and APAP+MPP high-dose group (APAP+H-MPP). The APAP+L-MPP (320 mg/kg per day) and APAP+H-MPP (640 mg/kg per day) groups received continuous MPP gavage for 2 weeks. A 12 h of APAP (200 mg/kg) gavage resulted in liver damage. Pathological alterations, antioxidant index levels, expression of toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB), and associated inflammatory factors were determined for each treatment group. The results revealed that the total amino acid content of MPP was 39.58 g/100 g, with Glu, Arg, Asp, Leu, Tyr, and Gly being the major amino acids. The molecular weight range of 0-1000 Da accounted for 73.54%, and 0-500 Da accounted for 62.84% of MPP. MPP ameliorated the pathological morphology and reduced the serum levels of alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase of AILI in mice. MPP significantly increased the activities of superoxide dismutase and glutathione peroxidase in the liver compared with the APAP group. MPP inhibited the expression of TLR4, NF-κB, interleukin-1ß (IL-1ß), and tumor necrosis factor-α (TNF-α) genes in AILI mice. MPP also inhibited the expression levels of inflammatory factors (TNF-α and IL-6). Our study concludes that MPP alleviates AILI in mice by enhancing antioxidant capacity and inhibiting TLR4/NF-κB pathway-related gene activation.

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The macadamia nut borer, Gymnandrosoma aurantianum Lima (Lepidoptera: Tortricidae), is the main pest of Macadamia integrifolia Maiden & Betche (Proteales: Proteaceae) in Central America. Despite its importance, there is little information on its reproductive behavior. We studied the calling behavior and effect of age on female sex pheromone production and male antennal response to the pheromone. Calling behavior of G. aurantianum females occurred at the onset of scotophase, between 17:00 and 20:00 h. The mean time spent calling was 64 min. It was observed that 30% of the 50 females exhibited a calling posture characterized by extrusion of the pheromone gland from the tip of the abdomen and they spread their wings slightly. Female age had no influence on the sex pheromone production, while male antennal response increased with age and pheromone dosage. The information obtained in this work contributes to understanding the sexual behavior of G. aurantianum and thus to the creation of strategies to control this important pest in macadamia.

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BACKGROUND: Despite the high risk of anaphylaxis in patients with a macadamia nut allergy (MdA), little is known about the significance of macadamia nut-specific immunoglobulin E (Md-sIgE). Thus, this study aimed to investigate the utility of Md-sIgE for predicting anaphylaxis. METHODS: Children with suspected MdA who visited our hospital were included. MdA was defined as either failing the 3-g macadamia nut (Md) oral food challenge (OFC) or confirming obvious immediate symptoms following Md ingestion. Non-MdA was defined as passing the 3-g Md OFC. RESULTS: A total of 41 children (29 [71%] males) with a median age of 7.7 years were included. The median Md-sIgE level was 2.23 kUA /L. Among the 21 children diagnosed with MdA, eight and 13 children did (An group) and did not (non-An group) develop anaphylaxis. Twenty children were included in the non-MdA group. The Md-sIgE level was significantly higher in the An group relative to the others (7.97 vs. 1.92 kUA /L, p < .001). Furthermore, the Md-sIgE level was significantly higher in the An group than in the non-An group (7.97 vs. 1.92 kUA /L, p = .02). However, there was no significant difference in the Md-sIgE between the non-An and non-MdA groups (1.92 vs. 1.90 kUA /L, p > .99). The area under the curve for predicting anaphylaxis in Md-sIgE was 0.92 (95% CI: 0.83-1.00), and the optimal cut-off value was 3.76 kUA /L. CONCLUSION: Md-sIgE levels were useful in predicting anaphylaxis. Above the cut-off value, we emphasize paying careful attention to the risk of anaphylaxis.

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This work aimed to identify novel angiotensin-converting-enzyme (ACE) inhibitory peptides from Macadamia integrifolia antimicrobial protein 2 (MiAMP2). The MiAMP2 protein was hydrolyzed through in silico digestion, and the generated peptides were screened for ACE inhibitory activity. The in silico enzyme digestion results revealed that 18 unreported peptides were obtained using AHTPDB and BIOPEP-UWM, and none were thought to be toxic based on absorption, distribution, metabolism, and excretion (ADMET) prediction. PGPR, RPLY, MNPQR, and AAPR were predicted to exhibit good biological activity. The molecular docking results revealed that the four peptides tightly bound to the active pocket of ACE via hydrogen bonds and hydrophobic interactions, among which RPLY and MNPQR bound to ACE more strongly. The in vitro assay results confirmed that RPLY and MNPQR peptides inhibited ACE via competitive manner. These results provide theoretical guidance for the development of novel foodborne antihypertensive peptides from Macadamia nut proteins. PRACTICAL APPLICATIONS: This study provides new insight on the inhibitory potential of Macadamia nut peptides against ACE, which may be further applied to the development of antihypertensive peptides in the medical industry.

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This paper presents the potential application of macadamia nut shells (MNS) in the bio-sorption of fluoride and its antimicrobial potency against common pathogens encountered in surface water resources. The efficiency of MNS in the sorption of fluoride was determined using batch mode experiments, while the antimicrobial potency was investigated using the well disc diffusion assay method. The maximum fluoride sorption capacity of 1.26 mg/g was recorded at an initial fluoride concentration of 5 mg/L, adsorbent dosage of 0.5 g/100 mL, contact time of 120 min and initial pH of 6. The adsorption kinetics data were better described with a pseudo second order model, indicating the dominance of the chemisorption mechanisms. The Langmuir adsorption isotherm model described the isotherm data suggesting a monolayered adsorption. The thermodynamic parameters, ∆Gº and ∆Hº, confirmed that F- sorption by MNS is a spontaneous and endothermic process. The bio-sorbent was regenerated for seven continuous cycles when HCl was used as regenerating solution. The antimicrobial studies revealed that MNS has minimal activity towards Escherichia coli, Staphylococcus aureus and Klebsiella pneumoniae. The MNS showed potentials for application in bio-sorption of fluoride. However, the doping of MNS with metal ions is recommended to enhance its anti-microbial potency.

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Macadamia nut is an increasingly popular food item of a healthy diet. However, macadamia nut is also a potent allergenic food. To date, there is little information about the allergenic proteins involved. In this study, using sera from macadamia nut allergic individuals, four IgE-binding proteins were detected. Their identities were determined by tandem mass spectrometry with de novo sequencing. Three IgE-reactive proteins, the vicilin Mac i 1, the legumin Mac i 2 and the antimicrobial peptide 2a/Mac i 1 (28-76) were purified from the nut while the non-specific lipid transfer protein was produced as a recombinant in Pichia pastoris. IgE-binding assays using sera from well-characterized groups of tree nut and/or peanut allergic patients revealed that the allergens were mainly recognized by sera from macadamia nut allergic individuals. Hence, these newly discovered allergens will enable molecular diagnostics to identify patients at high risk of macadamia nut allergy.

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This study investigated the physicochemical properties and 3D structure of Macadamia integrifolia antimicrobial protein 2 (MiAMP2) and its interaction with palmitoleic acid (POA) or oleic acid (OA) in macadamia oil. The 3D structure of MiAMP2 was constructed for the first time by ab initio modelling using the TrRosetta server. The results showed that MiAMP2 was highly hydrophilic and had seven disulfide bonds and higher α-helix and ß-sheet/turn contents. Molecular simulation showed that the hydrophobic pocket of MiAMP2 created a favourable environment for the binding of POA and OA. Free energy landscape and independent gradient model (IGM) analyses revealed that hydrogen bonds and van der Waals forces were the major driving forces stabilizing complexes formed by MiAMP2 and POA or OA. The present study provides a theoretical basis and new insight for the future development and utilization of macadamia nut protein in the food industry.

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The aim of the present study was to screen novel dipeptidyl peptidase IV (DPP-IV) inhibitory peptides from Macadamia integrifolia antimicrobial protein 2 (MiAMP2) and evaluate the potential antidiabetic targets and involved signaling pathways using in silico approaches. In silico digestion of MiAMP2 with pepsin, trypsin and chymotrypsin was performed with ExPASy PeptideCutter and the generated peptides were subjected to BIOPEP-UWM, iDrug, INNOVAGEN and Autodock Vina for further analyses. Six novel peptides EQVR, EQVK, AESE, EEDNK, EECK, and EVEE were predicted to possess good DPP-IV inhibitory potentials, water solubility, and absorption, distribution, metabolism, excretion, and toxicity properties. Molecular dynamic simulation and molecular docking displayed that AESE was the most potent DPP-IV inhibitory peptide and can bind with the active sites of DPP-IV through hydrogen bonding and van der Waals forces. The potential antidiabetic targets of AESE were retrieved from SwissTargetPrediction and GeneCards databases. Protein-protein interaction analysis identified BIRC2, CASP3, MMP7 and BIRC3 to be the hub targets. Moreover, the KEGG pathway enrichment analysis showed that AESE prevented diabetes through the apoptosis and TNF signaling pathways. These results will provide new insights into utilization of MiAMP2 as functional food ingredients for the prevention and treatment of diabetes.

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Macadamia nut contains important food allergens that potentially cause allergic reactions with severe adverse effects in infants and adults. Reliable and accurate detection of macadamia is critical to avoid allergic reactions. However, knowledge on macadamia allergen is scarce and a reliable detection method has not been reported, yet. In this study, an unbiased immunization and selection strategy was employed to select nanobodies (Nbs) recognizing specifically macadamia allergen, as well as to establish a detection method to unveil a macadamia protein contamination. An alpaca was immunized with a crude protein extract of macadamia followed by construction of a Nb library from its lymphocytes. The panning and screening of this immune Nb repertoire resulted in the selection of six target-specific Nbs. Nb-mediated immuno-capturing combined with mass spectrometry allowed us to identify the target as the macadamia vicilin-like antimicrobial peptides 2-3 (MiAMP2), a novel food allergenic protein abbreviated as Mac i 1. Later on, an immunoassay of a heterologous sandwich ELISA method based on the selected Nb-pairs was established, providing a linear response in the range of 0.442-2,800 µg/mL and with a limit of detection of 27.1 ng/mL. The dedicated immunoassay has been verified by detecting the antigen spiked in food samples. Our study provided evidence for the successful application of the unprejudiced strategy to retrieve Nbs against a priori undefined macadamia allergen. These target-specific Nbs were used to design a highly reliable and effective immunoassay.

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Macadamia nuts have high nutritional value and positive health attributes. Changes to the composition and availability of these compounds during roasting contribute to product quality. In this study, changes to the chemical composition of lipids (fatty acids, triglycerides, and free fatty acids) and other phytochemicals were analyzed, and a sensory evaluation was carried out of two major varieties of macadamia nuts planted in China, after roasting. Only small changes in fatty acid (FA) content and a slight decrease in total triglycerides (TAGs) were observed after roasting. The free fatty acid (FFA) content and the peroxide value were increased by roasting. The total available polyphenol content increased by 25.6% and the oxidative stability index of kernels increased by 21.6%. The sensory scores for taste and aroma were doubled by roasting. Overall, the sensory, nutritional quality, and oxidative stability of roasted macadamia nuts were greatly improved, compared with raw nuts.

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BACKGROUND: Macadamia nut can induce fatal allergic reactions and changes in dietary habits will raise their consumption in industrialised countries. Until now diagnosis of macadamia nut allergy by sIgE solely relies on the macadamia nut extract, but single components are lacking. METHODS: Macadamia nut proteins recognised by IgE from 2 macadamia nut extract positive sera were identified by mass spectrometry (vicilin-like antimicrobial peptides: VLAP). Sensitisation to macadamia nut extract and heterologously expressed isoform VLAP-2-3 was evaluated in 82 nut allergic (NA) and 27 tolerant (NT) patients (no tree nut allergy reported) comprehending 10 macadamia nut allergic (MA) and 18 explicitly reported macadamia nut tolerant patients (MT), using line blots. Co-sensitisation to additional VLAP isoforms and other vicilins was evaluated in 8 MA, 12 MT and 14 NA patients sensitised to VLAP-2-3. Functional properties were determined by indirect basophil activation. RESULTS: Even though proteins recognised by IgE were identified as VLAP-2-1, 2-2 and 2-3, only peptides specifically belonging to VLAP-2-3 were detected by mass spectrometry. The macadamia nut extract was recognised by 33% of NA patients (27/82) including 3 MA patients and 26% of NT patients (7/27, 3 MT). Similarly, 29% of NA (24/82) patients showed partly strong sIgE-binding to VLAP-2-3 including 3 MA patients with systemic reactions to macadamia nut. Contrary, VLAP-2-3 was recognised by only 2 NT (1 MT) patients (7%) with very low sIgE titres. Simultaneous recognition of the isoforms VLAP-2-1 and 2-2 was observed in all patients positive for VLAP-2-3 with partly reduced sIgE titres in 59% of these patients. Additionally, all three VLAP isoforms were able to repeatedly induce BAT reactivity upon sensitisation with a MA serum. CONCLUSION: VLAP proteins are the first described macadamia nut components with serological and functional allergenic properties and they are associated with systemic reactions to macadamia nut.

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In this study, we present a systematic proteomic overview of macadamia nut using a label-free shotgun proteomic approach. We identified 947 proteins in 723 clusters and gene ontology analysis revealed proteins across 46 functional categories including carbohydrate metabolism (10%), protein metabolic processes (5%), amino acid metabolism (4%), transport (4%), stress response (3%), lipid metabolism (3%), protein folding (3%) and defense response (1.4%). The defense response proteins accounted for 24% of the total peptide abundance. The vicilin-like macadamia antimicrobial peptides 2-3 (MiAMP2) was the most abundant protein, followed by glyceraldehyde-3-phosphate dehydrogenase 3, 11S legumin-like protein, 2-phospho-D-glycerate hydrolase and heat shock 70 kDa protein among others. The cascading of amino acid and carbohydrate metabolic pathways in macadamia nut were constructed against reference maps from KEGG and proposed for the first time. Results were also indicative of useful protein candidates with possible allergenic potential and cross-reactivity in macadamia nut. The in-silico analysis revealed homology and linear epitope similarities to known allergens such as conglutin ß allergen from lupin, Jug r2 vicilin allergens from walnut, Ara h3 11S globulin from peanut, small rubber particle protein Hev b3, hevein, enolase 2, HSP 70kDa Cla h4, Der f28 allergen, and methylglyoxalases. Label-free shotgun proteomics reveal valuable insights into the genetic and biological makeup of macadamia nut proteome and provide guidance on protein candidates with allergenic potential for further immunological investigation. Data are available via ProteomeXchange with identifier PXD015364.

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Macadamia nut shell (MNS) is a type of waste lignocellulose obtained from macadamia nut production processing. Large MNS wastes caused serious resource waste and environmental pollution. So, preparation of hydrochars from MNS via hydrothermal carbonization (HTC) is of great significance. HTC of MNS was conducted to study the effect of process parameters, including HTC temperature (180-260°C) and residence time (60-180 min) on the properties of hydrochars. Results showed that the increase in HTC temperature and residence time decreased the mass yield of hydrochars and increased the high heating value of hydrochars. Furthermore, the C content of hydrochars increased, whereas the H and O contents decreased. Mass yield of hydrochar is 46.59%, energy yield is 64.55% and the higher heating value is 26.02 MJ kg-1 at a temperature of 260°C and time of 120 min. The surface structure of hydrochars was rougher compared with that of MNS as observed via scanning electron microscopy. The chemical and combustion behaviour of MNS and hydrochars was analysed by Fourier transform infrared spectroscopy, and thermogravimetric analysis indicated that decarboxylation and dehydration reactions were the predominant pathways during the HTC process. Results showed that HTC can facilitate the transformation of MNS into solid fuel.

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Ventilation air methane (VAM), which is the main source of greenhouse gas emissions from coal mines, has been a great challenge to deal with due to its huge flow rates and dilute methane levels (typically 0.3-1.0 vol%) with almost 100% humidity. As part of our continuous endeavor to further improve the methane adsorption capacity of carbon composites, this paper presents new carbon composites derived from macadamia nut shells (MNSs) and incorporated with carbon nanotubes (CNTs). These new carbon composites were fabricated in a honeycomb monolithic structure to tolerate dusty environment and to minimize pressure drop. This paper demonstrates the importance of biomass particle size distributions when formed in a composite and methane adsorption capacities at low pressures relevant to VAM levels. The selectivity of methane over nitrogen was about 10.4 at each relevant partial pressure, which was much greater than that (6.5) obtained conventionally (at very low pressures), suggesting that capturing methane in the presence of pre-adsorbed nitrogen would be a practical option. The equilibrium and dynamic performance of biomass-derived carbon composites were enhanced by 30 and 84%, respectively, compared to those of our previous carbon fiber composites. In addition, the presence of moisture in ventilation air resulted in a negligible effect on the dynamic VAM capture performance of the carbon composites, suggesting that our carbon composites have a great potential for site applications at coal mines because the cost and performance of solid adsorbents are critical factors to consider.

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This data article provides the results of skin sensitization testing for emu and macadamia nut oil on 20 participants (ages 22-59 years old), including 3 men and 17 women. The test was carried out by performing a standard patch test using a Finn Chamber on Scanpor tape. The oils were applied to the participant's back using the tape and left in place for 24 h. After 1- and 24-h from removal of the tape, the reaction of the participant's skin was judged based on a scoring method recommended by Japanese Patch Test Research Group. Results are shown in table format.