Groundnut and tree nuts: a comprehensive review on their lipid components, phytochemicals, and nutraceutical properties.

The health benefits of nut consumption have been extensively demonstrated in observational studies and intervention trials. Besides the high nutritional value, countless evidences show that incorporating nuts into the diet may contribute to health promotion and prevention of certain diseases. Such benefits have been mostly and certainly attributed not only to their richness in healthy lipids (plentiful in unsaturated fatty acids), but also to the presence of a vast array of phytochemicals, such as polar lipids, squalene, phytosterols, tocochromanols, and polyphenolic compounds. Thus, many nut chemical compounds apply well to the designation "nutraceuticals," a broad umbrella term used to describe any food component that, in addition to the basic nutritional value, can contribute extra health benefits. This contribution analyses the general chemical profile of groundnut and common tree nuts (almond, walnut, cashew, hazelnut, pistachio, macadamia, pecan), focusing on lipid components and phytochemicals, with a view on their bioactive properties. Relevant scientific literature linking consumption of nuts, and/or some of their components, with ameliorative and/or preventive effects on selected diseases - such as cancer, cardiovascular, metabolic, and neurodegenerative pathologies - was also reviewed. In addition, the bioactive properties were analyzed in the light of known mechanistic frameworks.

Spray drying and rehydration of macadamia oil-in-water emulsions: Impact of macadamia protein isolate to chitosan hydrochloride ratio.

The utilization of oils in the food industry can be facilitated by converting into a powdered form using microencapsulation technologies. In this study, coatings formed from macadamia protein isolate (MPI) and chitosan hydrochloride (CHC) were assessed for their ability to facilitate the microencapsulation of macadamia oil by spray dried, and all encapsulation efficiency was higher than 87.0%. The physicochemical properties of macadamia oil powders were then characterized. In addition, changes in the particle size, aggregation state, and creaming stability of rehydrated emulsions were analyzed during storage. The addition of CHC significantly enhanced the water-solubility and wettability but decreased the flowability of microencapsulated oil. Powdered macadamia oil produced at MPI/CHC = 5:1 had the highest encapsulation efficiency (94.2%), best oxidation stability (<4 meq/kg), and best rehydration properties. Overall, MPI/CHC could be used as a good emulsifier for producing stable rehydrated emulsion, which may therefore be useful in certain food applications.

Development and evaluation of a vegetable oil blend formulation for cutaneous wound healing.

This work aimed to evaluate the in vivo capacity of a vegetable oil blend formulation (VOB) developed to accelerate cutaneous wound closure. Total thickness wounds were punctured on the skin on the back side of each animal and topically treated with the VOB formulation, Dersani® ointment or the vehicle control. After 2, 7, 14, 21 days post-wounding, five animals from each group were euthanized, and the rates of wound closure and re-epithelialization were evaluated. The wounds were harvested for histological and biochemical analysis. VOB resulted in faster and greater re-epithelialization in the in vivo excisional wounds, exhibiting significant wound area reduction of 8.9, 8.0, 35.1, 45.2 and 47.0% after 2, 5, 10, 14 and 21 days post-wounding, respectively, when compared with the vehicle control. Histological and biochemical analyses showed that the VOB-treated wounds exhibited a significant increase of granular tissue and controlled inflammatory response by modulation of the release of pro-inflammatory cytokines TNF-α, IL-6 and IL-1. Moreover, VOB-treated wounds showed a significant and concrete increase in the deposition and organisation of collagen fibres in the wound site and improved the quality of the scar tissue. Altogether, these data revealed that VOB accelerates wound healing processes and might be beneficial for treating wound disorders.

Chemical characterization of a variety of cold-pressed gourmet oils available on the Brazilian market.

Different specialty extra virgin oils, produced by cold-pressing fruits/nuts (olive, pequi, palm, avocado, coconut, macadamia and Brazil nut) and seeds (grapeseed and canola), and retailed in the Brazilian region of Minas Gerais, were chemically characterized. Specifically, for each type of oil, the fatty acid composition was elucidated by GC-FID, the contents of selected polyphenols and squalene were determined respectively by UHPLC-MS and UHPLC-PDA, whereas minerals were explored by means of ICP-MS. Olive oil was confirmed to have the highest MUFA content due to a valuable level of oleic acid, while oils from grapeseed, Brazil nut and canola were marked by nutritionally important PUFA levels. The highest SFA content found in coconut oil was mainly due to the high levels of lauric acid, known for its advantageous HDL-raising effects. As for polyphenols, gourmet oils from palm, coconut and canola showed higher levels of phenolic acids (e.g. p-hydroxybenzoic, ferulic, syringic, acids) than olive oil, which was though characterized by peculiar antioxidants, such as tyrosol and hydroxytyrosol. Also, olive oil had the highest amount of squalene, followed by the oil from Brazil nut. Finally, all the investigated oils had very low levels (order of µg/kg) of pro-oxidant elements, such as Cu, Fe and Mn. Overall, these findings may fill the gaps still present in literature on certain compositional aspects of commercially available gourmet oils.

In vitro fermentation of nuts results in the formation of butyrate and c9,t11 conjugated linoleic acid as chemopreventive metabolites.

PURPOSE: The consumption of foods rich in dietary fiber and polyunsaturated fatty acids such as nuts can contribute to a healthy diet. Therefore, the formation of fermentation end-products which might exert chemopreventive effects regarding colon cancer was investigated after an in vitro simulated digestion and fermentation of nuts using human fecal microbiota. METHODS: Fermentation supernatants (FS) and pellets (FP) were obtained after an in vitro fermentation of hazelnuts, almonds, macadamia, pistachios and walnuts. Short-chain fatty acids (SCFA) and bile acids (BA) in FS as well as fatty acids in FP were analyzed via gas chromatography. Malondialdehyde (MDA) levels in FS were determined photometrically. RESULTS: Fermentation of nuts resulted in 1.9- to 2.8-fold higher concentrations of SCFA compared to the control and a shift of molar ratios toward butyrate production. In vitro fermentation resulted in the formation of vaccenic acid (C18:1t11, 32.1 ± 3.2 % FAME; fatty acid methyl ester) and conjugated linoleic acid (c9,t11 CLA, 2.4 ± 0.7 % FAME) exclusively in fermented walnut samples. Concentrations of secondary BA deoxycholic-/iso-deoxycholic acid (6.8-24.1-fold/4.9-10.9-fold, respectively) and levels of MDA (1.3-fold) were significantly reduced in fermented nut samples compared to the control. CONCLUSION: This is the first study that demonstrates the ability of the human fecal microbiota to convert polyunsaturated fatty acids from walnuts to c9,t11 CLA as a potential chemopreventive metabolite. In addition, the production of butyrate and reduction in potential carcinogens such as secondary BA and lipid peroxidation products might contribute to the protective effects of nuts regarding colon cancer development.

Aging effects on macadamia nut oil studied by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry.

High-resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry is successfully used in the detailed molecular analysis of aged macadamia nut oils. The results are consistent with peroxide values, the current industry measure for rancidity, and provide detailed molecular information on the oxidative and hydrolytic degeneration of such oils. Mass analysis of macadamia oil samples stored for extended periods at 6 °C revealed that oils obtained by the cold press method are more susceptible to aging than those obtained using modified Soxhlet or accelerated solvent extraction methods.

Depression scores predict adherence in a dietary weight loss intervention trial.

BACKGROUND & AIMS: Depression has a complex association with cardiometabolic risk, both directly as an independent factor and indirectly through mediating effects on other risk factors such as BMI, diet, physical activity, and smoking. Since changes to many cardiometabolic risk factors involve behaviour change, the rise in depression prevalence as a major global health issue may present further challenges to long-term behaviour change to reduce such risk. This study investigated associations between depression scores and participation in a community-based weight management intervention trial. METHODS: A group of 64 overweight (BMI > 27), otherwise healthy adults, were recruited and randomised to follow either their usual diet, or an isocaloric diet in which saturated fat was replaced with monounsaturated fat (MUFA), to a target of 50% total fat, by adding macadamia nuts to the diet. Subjects were assessed for depressive symptoms at baseline and at ten weeks using the Beck Depression Inventory (BDI-II). Both control and intervention groups received advice on National Guidelines for Physical Activity and adhered to the same protocol for food diary completion and trial consultations. Anthropometric and clinical measurements (cholesterol, inflammatory mediators) also were taken at baseline and 10 weeks. RESULTS: During the recruitment phase, pre-existing diagnosed major depression was one of a range of reasons for initial exclusion of volunteers from the trial. Amongst enrolled participants, there was a significant correlation (R = -0.38, p < 0.05) between BDI-II scores at baseline and duration of participation in the trial. Subjects with a baseline BDI ≥10 (moderate to severe depression symptoms) were more likely to dropout of the trial before week 10 (p < 0.001). BDI-II scores in the intervention (MUFA) diet group decreased, but increased in the control group over the 10-week period. Univariate analysis of variance confirmed these observations (adjusted R(2) = 0.257, p = 0.01). Body weight remained static over the 10-week period in the intervention group, corresponding to a relative increase in the control group (adjusted R(2) = 0.097, p = 0.064). CONCLUSIONS: Depression symptoms have the potential to affect enrolment in and adherence to dietbased risk reduction interventions, and may consequently influence the generalisability of such trials. Depression scores may therefore be useful for characterising, screening and allocating subjects to appropriate treatment pathways.

Growth performance and carcass characteristics of feedlot cattle fed different levels of macadamia oil cake.

Eighteen cattle (six Bonsmara males, seven Simmanteler x Beefmaster males and five Simmanteler x Beefmaster females) were assigned to three diets containing 0% (Control), 10% and 20% Macadamia oil cake to evaluate the effects of different levels of Macadamia oilcake (MOC) on feed intake, growth performance and carcass characteristics of feedlot cattle. Differences in average feed intake were not significant (P > 0.05). Average daily gains on the 0% and 20% MOC diets were not significantly different (P < 0.05) but were significantly higher than the average gain on 10% MOC (P < 0.05). The inclusion of 20% MOC increased feed conversion ratio significantly (P < 0.05) compared with the other two treatments. The control group had significantly heavier warm carcasses than the 10% and 20% MOC groups and the 20% MOC group had significantly heavier carcasses than the 10% MOC group. The inclusion of MOC did not significantly affect the dressing percentage and conformation scores of the animals (P > 0.05). There were no condemned livers, suggesting that either there were no toxic factors in the feed or, even if present, were probably inactive in the liver.

Macadamia nut consumption modulates favourably risk factors for coronary artery disease in hypercholesterolemic subjects.

Macadamia nuts are rich source of monounsaturated fats (oleic and palmitoleic acids) and contain polyphenol compounds, therefore, their consumption can be expected to impart health benefits to humans. This study was conducted to examine the effects of consuming macadamia nuts in hypercholesterolemic male individuals on plasma biomarkers of oxidative stress, coagulation and inflammation. Seventeen hypercholesterolemic male subjects were given macadamia nuts (40-90 g/day), equivalent to 15% energy intake, for a period of 4 weeks. As expected, monounsaturated fatty acids (16:1n-7, 18:1n-9 and 20:1n-9) were elevated in the plasma lipids of all volunteers following intervention with macadamia nuts. Plasma markers of inflammation (leukotriene, LTB(4)) and oxidative stress (8-isoprostane) were significantly lower (1,353 +/- 225 vs. 1,030 +/- 129 pg/mL and 876 +/- 97 vs. 679 +/- 116 pg/mL, respectively) within 4 weeks following macadamia nut intervention. There was a non-significant (23.6%) reduction in the plasma TXB(2)/PGI(2) ratio following macadamia nut consumption. This study demonstrates, for the first time, that short-term macadamia nut consumption modifies favourably the biomarkers of oxidative stress, thrombosis and inflammation, the risk factors for coronary artery disease, despite an increase in dietary fat intake. These data, combined with our previous results on cholesterol-lowering effects of macadamia nuts, suggest that regular consumption of macadamia nuts may play a role in the prevention of coronary artery disease.