Bolling, B.W., J.B. Blumberg, C.-Y.O. Chen. 2010. The influence of roasting, pasteurisation, and storage on the polyphenol content and antioxidant capacity of California almond skins. Food Chem.doi:10.1016/j. foodchem.2010.05.058.
Polyphenols and antioxidant activity of skins from California almonds subjected to roasting, pasteurisation, and storage were determined by LC-MS quantification, total phenols (TP), and ferric reducing antioxidant power (FRAP). Pasteurisation did not significantly change TP, FRAP, or flavonoids and phenolic acids (FP). Roasted almonds had 26% less TP and 34% less FRAP than raw, but equivalent FP (n = 12). Storing almonds at 4 and 23 ºC for 15 mo resulted in gradual increases in FP, up to 177% and 200%, respectively (n = 13). At 4 ºC and 15 mo, polyphenols increased 18-fold for p-hydroxybenzoic acid, whilst others were 45–200% higher compared to baseline values. Isorhamnetin-3-O-rutinoside accounted for 48% of the increase in FP. After 15 mo, FRAP and TP increased to 200% and 190% of initial values. Accelerated ageing of whole almonds increased FP content by 10% after 3 days, but TP and FRAP values were not significantly different from baseline to day 10. Thus, in almond skins, roasting decreases TP and FRAP but not FP, whilst storage for up to 15 mo doubles F
Mandalari, G., R.M. Faulks, C. Bisignano, K.W. Waldron, A. Narbad, M.S.J. Wickham. 2010. In vitro evaluation of the prebiotic properties of almond skins (Amygdalus communis L.). FEMS Microbiol. Lett.304:116-122.
In this study we investigated the potential prebiotic effect of natural (NS) and blanched (BS) almond skins, the latter being a byproduct of the almond-processing industry. A full model of the gastrointestinal tract, including in vitro gastric and duodenal digestion, followed by colonic fermentation using mixed fecal bacterial cultures, was used. Both NS and BS significantly increased the population of bifidobacteria and Clostridium coccoides/Eubacterium rectale group, resulting in a prebiotic index (3.2 for BS and 3.3 for NS) that compared well with the commercial prebiotic fructo-oligosaccharides (4.2) at a 24-h incubation. No significant differences in the proportion of gut bacteria groups and in short-chain fatty acid production were detected between NS and BS, showing that polyphenols present in almond skins did not affect bacterial fermentation. In conclusion, we have shown that dietary fiber from almond skins altered the composition of gut bacteria and almond skins resulting from industrial blanching could be used as potential prebiotics.
Mandalari, G., C. Bisignano, M. D’Arrigo, G. Ginestra, A. Arena, A. Tomaino, M.S.J. Wickham. 2010. Antimicrobial potential of polyphenols extracted from almond skins. Lett. Appl. Microbiol. 51(1):83–89.
Aims: To evaluate the antimicrobial properties of flavonoid-rich fractions derived from natural and blanched almond skins, the latter being a by-product from the almond processing industry. Methods and Results: Almond skin extracts were tested against Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica, Serratia marcescens), Gram-positive bacteria (Listeria monocytogenes, Enterococcus hirae, Staphylococcus aureus, Enterococcus durans) and the yeast Candida albicans. Almond skin fractions were found to have antimicrobial activity against L. monocytogenes and Staph. aureus in the range 250–500 µg ml-1), natural skins showing antimicrobial potential against the Gram-negative Salm. enterica. The interactions between three almond skin flavonoids were also evaluated with isobolograms. Conclusions: Pairwise combinations of protocatechuic acid, naringenin and epicatechin showed both synergistic and indifferent interactions against Salm. enterica and Staph. aureus. Antagonism was observed against L. monocytogenes with all combinations tested. Further studies need to be performed to understand the mechanisms responsible for these interactions. Significance and Impact of the Study: Almond skins are a potential source of natural antimicrobials.
Arena, A., C. Bisignano, G. Stassi, G. Mandalari, M.S.J. Wickham, G. Bisignano. 2010. Immunomodulatory and antiviral activity of almond skins. Immunol. Lett. 132(1-2):18-23.
The elimination of a viral infection requires a proinflammatory host response (type 1 immunity), characterized by activation of mononuclear cells and production of proinflammatory cytokines, such as interferons (IFNs), tumor necrosis factor (TNF)-alpha and interleukin (IL)-12. On the other hand, IL-4 and IL-10 play a role in decreasing the inflammatory response supported by helper T (Th)1 cells. In this study we evaluated the effects of almond skins on the release of cytokines by peripheral blood mononuclear cells (PBMC), either infected or not with herpes simplex virus type 2 (HSV-2). Natural (NS) and blanched almond skins (BS) were subjected to simulated gastric and duodenal digestion and used at not cytotoxic concentrations. NS induced a significant decrease in HSV-2 replication, whereas extracts obtained from BS did not significantly influence the viral replication. High levels of cytokines production, such as IFN-alpha (38±5.3 pg/ml), IL-12 (215±17.1 pg/ml), IFN-gamma (5±0.7 IU/ml), TNF-alpha (3940±201.0 pg/ml), were detected. Moreover, IL-10 (210±12.2 pg/ml) and IL-4 (170±21.4 pg/ml), representative of Th2 responses, were found. Our data suggest that almond skins improve the immune surveillance of PBMC towards viral infection, both by triggering the Th1 and Th2 subsets.
Mandalari, G., A. Tomaino, G.T. Rich, R. Lo Curto, T. Arcoraci, M. Martorana, C. Bisignano, A. Saija, M.L. Parker, K.W. Waldron, M.S.J. Wickham. 2010. Polyphenol and nutrient release from skin of almonds during simulated human digestion. Food Chem. 122:1083-1088.
The bioaccessibility of nutrients and phytochemicals from almond skin has not been previously evaluated. We quantified the release of lipid, protein and polyphenols during simulated human digestion from natural (NS) and blanched (BS) skins, the latter being a by-product of the almond industry. Higher percentages of polyphenols were released from NS compared to BS during in vitro digestion. Most of the limited release of lipid and protein occurred during gastric digestion, with no significant differences between NS and BS. The total dietary fiber content was 45% for NS and 46% for BS, glucose and galacturonic acid being the major sugars present. No changes in dietary fiber composition and distribution of autofluorescent phenolics were observed in the cell walls of almond skin after simulated digestion. In the GI tract, the cell walls may therefore function as a useful source of fermentable fiber with beneficial implications for gut health.
Bolling, B.W., D.L. McKay, J. B. Blumberg, 2010. The phytochemical composition and antioxidant actions of tree nuts. Asia Pac J Clin Nutr. 19(1):117-123 117.
In addition to being a rich source of several essential vitamins and minerals, mono- and polyunsaturated fatty acids, and fiber, most tree nuts provide an array of phytochemicals that may contribute to the health benefits attributed to this whole food. Although many of these constituents remain to be fully identified and characterized, broad classes include the carotenoids, hydrolyzable tannins, lignans, naphthoquinones, phenolic acids, phytosterols, polyphenols, and tocopherols. These phytochemicals have been shown to possess a range of bioactivity, including antioxidant, antiproliferative, anti-inflammatory, antiviral, and hypocholesterolemic properties. This review summarizes the current knowledge of the carotenoid, phenolic, and tocopherol content of tree nuts and associated studies of their antioxidant actions in vitro and in human studies. Tree nuts are a rich source of tocopherols and total phenols and contain a wide variety of flavonoids and proanthocyanidins. In contrast, most tree nuts are not good dietary sources of carotenoids and stilbenes. Phenolic acids are present in tree nuts but a systematic survey of the content and profile of these compounds is lacking. A limited number of human studies indicate these nut phytochemicals are bioaccessible and bioavailable and have antioxidant actions in vivo.
Zhang, J., P.M. Kris-Etherton , J.T. Thompson, J.P. Vanden Heuvel, 2010. Effect of pistachio oil on gene expression of IFN-induced protein with tetratricopeptide repeats 2: A biomarker of inflammatory response. Mol. Nutr. Food Res. 54:1–10.
When incorporated into the diet, pistachios have a beneficial effect on lipid and lipoprotein profiles. However, little is known about potential anti-inflammatory properties. This study was conducted to determine whether pistachio oil and an organic extract from pistachio oil extract (PE) regulated expression of inflammation-related genes. A mouse macrophage cell line (RAW 264.7 cells) was treated with pistachio oil and gene expression microarray analyses were performed. Pistachio oil significantly affected genes involved in immune response, defense response to bacteria, and gene silencing, of which INF-induced protein with tetratricopeptide repeats 2 (Ifit-2) was the most dramatically reduced. PE reduced the LPS-induced Ifit-2 by 78% and the bioactive molecules contained in PE, linoleic acid, and β-sitosterol recapitulated this inhibition. Promoter analysis identified two adjacent IFN-stimulated response elements, which lie between -110 and -85bp of the 5’-flanking region of the Ifit-2 promoter, as being responsive to LPS activation and inhibition by PE. Our results indicate that pistachio oil and bioactive molecules present therein decrease Ifit-2 expressions, and due to the sensitivity of this effect, this gene is a potential biomarker for monitoring diet-induced changes in inflammation.
Alturfan, A.A., E. Emekli-Alturfan, E. Uslu, 2009. Consumption of pistachio nuts beneficially affected blood lipids and total antioxidant activity in rats fed a high-cholesterol diet. Folia Biol (Praha). 55(4):132-6.
Although nuts are typically high in dietary fat, novel studies have shown that regular consumption of these heart-healthy foods might confer a beneficial effect on cardiovascular disease risk. In the present study, we aimed to analyse the effects of pistachio consumption on blood lipids, antioxidant activity, oxidative stress and sialic acid levels in high-fat-fed rats for 8 weeks. The oxidant-antioxidant status was evaluated by the determination of lipid peroxidation (thiobarbituric acid-reactive substances), total antioxidant activity, reduced glutathione content, activity of superoxide dismutase and total thiol levels. Furthermore, tissue damage was evaluated by total sialic acid levels in serum. Total cholesterol, triglycerides, sialic acid and thiobarbituric acid-reactive substances significantly increased whereas total antioxidant activity, reduced glutathione, total thiol levels significantly decreased in the hyperlipidaemic group compared to the control group. Pistachio consumption significantly decreased triglycerides and thiobarbituric acid-reactive substance levels and significantly increased total antioxidant activity in the hyperlipidaemic group. In conclusion, pistachio supplementation may improve blood lipids and ameliorate oxidative stress in experimental hyperlipidaemia, which may have beneficial applications in the prevention of cardiovascular diseases. However, its antioxidant mechanisms remain to be investigated.
Ballistreri, G., E. Arena, B. Fallico, 2009. Influence of ripeness and drying process on the polyphenols and tocopherols of Pistacia vera L. Molecules. 14:4358-4369.
This paper highlights, for the first time, the changes in the phenolics fraction (anthocyanins, flavonoids and stilbenes) and tocopherols of unpeeled Pistacia vera L. var. bianca with ripening, and the effect of the sun-drying process. The total polyphenol levels in pistachios, measured as mg of Gallic Acid Equivalent (GAE), were: 201 ± 10.1, 349 ± 18.3 and 184.7 ± 6.2 mg GAE/100 g DM in unripe, ripe and dried ripe samples, respectively. Most phenolics in ripe pistachios were found to be anthocyanins. They increased with ripening, while the sun drying process caused a susbtantial loss. Flavonoids found in all pistachio samples were daidzein, genistein, daidzin, quercetin, eriodictyol, luteolin, genistin and naringenin, which decreased both with ripening and drying. Before the drying process both unripe and ripe pistachios showed a higher content of transresveratrol than dried ripe samples. γ-Tocopherol was the major vitamin E isomer found in pistachios. The total content (of α- and γ-tocopherols) decreased, both during ripening and during the drying process. These results suggested that unpeeled pistachios can be considered an important source of phenolics, particularly of anthocyanins. Moreover, in order to preserve these healthy characteristics, new and more efficient drying processes should be adopted.
Yang, J. 2009. Brazil nuts and associated health benefits: A review. LWT – Food Science and Technology.42:1573–1580.
Epidemiological studies have shown an inverse relationship between nut intakes and chronic diseases such as cardiovascular diseases and cancers. The composition of lipids, minerals, and phytochemicals, and their associated health functions in Brazil nuts are critically reviewed. The nuts have high nutritive food value containing 60–70% oil and 17% protein. Brazil nuts contain abundant dietary antioxidants, especially selenium (Se). One single Brazil nut provides 160% of the US Recommended Daily Allowance (RDA) of selenium – perhaps the best source of Se from plant-based foods. Brazil nuts possess phenolics and flavonoids in both free and bound forms and are rich in tocopherol, phytosterols, and squalene. These compounds’ possible beneficial effects are due to their antioxidant and antiproliferative activities, which are linked to a reduced risk for developing atherosclerosis and cance
