Carbohydrate composition and color development during drying and roasting of macadamia nuts (Macadamia integrifolia)

Research was conducted to determine whether variability in sugar content contributes to differences in kernel browning during processing of macadamia nut (Macadamia integrifolia) cultivars, Kau (HAES 344), Keaau (HAES 660), Keauhou (HAES 246), and Kakea (HAES 508). At harvest, total sugar content of fresh macadamia kernels varied from 2.9 to 5.6 g/100 g dry weight basis (db), and the average moisture content ranged from 15.6 to 23.6 g/100 g fresh weight. Cultivars differed in kernel sucrose content, but not reducing sugar content. Reducing sugars decreased during drying, and kernel centers darkened slightly. An incremental drying process limited sucrose hydrolysis, minimizing the amount of glucose and fructose available for browning reactions. Therefore, the centers of roasted kernels were not darker than dried kernels. The variability in sugar composition in fresh kernels had a minimal impact on color quality when low-temperature drying and roasting at 125 °C were used. However, when roasted kernels received from a processor were separated based on color quality, kernels with internal or external browning had higher reducing sugar concentrations (0.24-0.27 g/100 g db) than cream-colored kernels (0.03 g/100 g db). Immature kernels had higher sucrose and reducing sugar contents and more browning than mature kernels. During commercial processing, optimal conditions may not be achieved and the presence of immature nuts can contribute to kernel browning.     

Chemical compositions,functional properties,and microstructure of defatted macadamia flours

The objective of this research was to study the chemical compositions, functional properties, and microstructure of partially defatted flours (PDF, 12–15% fat, dry basis (db)) and totally defatted flours (TDF, 1% db fat) from three macadamia cultivars, PY 741, DS 344, and DS 800, grown in Northern Thailand. The defatted flours were high in protein (30.40–36.45% db) and carbohydrate (49.29–57.09% db). For each macadamia cultivar, while emulsion activities and emulsion stabilities of the TDF tended not to be different from those of the PDF (p > 0.05), TDF had significantly greater water absorption capacities (WAC), oil absorption capacities and foaming capacities (FC), but had significantly lower foaming stability (FS) than the PDF (p ? 0.05). The TDF from PY 741 cultivar possessed the highest WAC and FC but the lowest FS. The variation in the functional properties of the defatted flours could mainly arise from the difference in the quantity and characteristics of the proteins in the flours. Structure determination of macadamia flours showed that the proteins bodies and starch granules were embedded in kernel tissues. The starch granules were oval and approximately 10 μm in diameter.     

Antioxidative potential of cashew phenolics in food and biological model systems as affected by roasting

The effect of different roasting conditions on antioxidant capacity of phenolics of cashew nuts and their testa was evaluated using several food and biological model systems. Total phenolic content (TPC) of cashew extracts was determined and accelerated oxidative stability of stripped corn oil in the presence of cashew extracts evaluated. In addition, the antioxidant activity of the extracts was assessed in a β-carotene-linoleate and a cooked comminuted pork model system. Inhibition of oxidation of human low density lipoprotein (LDL) cholesterol and stand breaking of supercoiled deoxyribonucleic acid (DNA) was also investigated. The TPC ranged from 5 to 791 mg gallic acid equivalents/g crude extract. In general, whole cashew nuts and testa extracts demonstrated stronger antioxidant activity than that of the cashew kernel. The inhibition percentage of LDL cholesterol oxidation, as evaluated by conjugated dines formation, of cashew kernels was higher than that of testa and was 69% at the end of 24 h incubation. Extracts of roasted cashew nut showed considerable antioxidative efficiency in model systems employed in this study, however, the effect was not significantly (P ? 0.05) different from that of their raw counterparts, except for the accelerated oxidative stability assay. The results suggest that whole cashew nut and testa extracts could be used as a potential source of natural antioxidants in certain food applications and for disease risk reduction.     

Antioxidant capacity,total phenolics,glucosinolates and colour parameters of rapeseed cultivars

The antioxidant capacity of twenty nine rapeseed varieties was determined by using ferric reducing antioxidant power (FRAP) and 2,2′-diphenyl-1-picrylhydrazyl (DPPH) methods. Mean FRAP (3190–6326 μmol Trolox/100 g) and DPPH (3194–6346 μmol Trolox/100 g) values for methanolic extracts of rapeseed cultivars did not differ significantly. Moreover, the total content of phenolics (756–1324 mg sinapic acid/100 g), glucosinolates (4.2–87.5 μmol/g, respectively), erucic acid (0.0–56.1%) and colour parameters of the studied rapeseed cultivars were analysed. Antioxidant capacity determined by FRAP and DPPH methods correlated significantly with total phenolic content (TPC) in rapeseed cultivars (r = 0.9332, 0.9339, p < 0.001). Also, significant, inverse correlations were found between antioxidant capacity, total phenolics and luminosity (L^∗) or red colour intensity (a^∗) of rapeseed cultivars. Principal component analysis (PCA) allowed the rapeseed varieties to be differentiated based on their antioxidant capacities, total amounts of phenolics, glucosinolates, erucic acid and colour parameters.     

Carotenoid compositions of coloured tomato cultivars and contribution to antioxidant activities and protection against H2O2-induced cell death in H9c2

The carotenoid compositions, antioxidant activities and the potential cardio-protective role of 13 tomato cultivars with distinct colour were studied. Colour coordinates were evaluated by colorimeter and the carotenoid compositions were analysed by UPLC. Red tomatoes had the highest total carotenoid contents (TCC) and antioxidant activities, followed by purple, orange, pink and yellow ones. The TCC were 120.5–278.0 μg/g DW, and the antioxidant activities were 21.32–40.07 μmol TE/g DW (PCL), 64.42–89.98% (DPPH) and 10.47–13.76 μmol TE/g DW (ORAC), respectively. The lipophilic extracts were also found to prevent cell death in a cell-based model system using cardiac H9c2 cells and H₂O₂, via attenuation of the caspase-3 and matrix metalloproteinase-2 activities. The extracts of different tomatoes showed strong but different antioxidant activities. Roles of total and individual carotenoids in the antioxidant activities were studied and lycopene showed the highest correlation. Results of this study can be used to guide the development of new tomato cultivars and functional foods, and benefit the consumers.     

Sacha inchi (Plukenetia volubilis): A seed source of polyunsaturated fatty acids,tocopherols, phytosterols,phenolic compounds and antioxidant capacity

Fatty acids (FA), phytosterols, tocopherols, phenolic compounds, total carotenoids and hydrophilic and lipophilic ORAC antioxidant capacities were evaluated in 16 cultivars of Sacha inchi (SI) seeds with the aim to valorise them and offer more information on the functional properties of SI seeds. A high α linolenic (α-Ln) fatty acid content was found in all cultivars (ω3, 12.8–16.0 g/100 g seed), followed by linoleic (L) fatty acid (ω6, 12.4–14.1 g/100 g seed). The ratio ω6/ω3 was within the 0.83–1.09 range. γ- and δ-tocopherols were the most important tocopherols, whereas the most representative phytosterols were β-sitosterol and stigmasterol. Contents of total phenolics, total carotenoids and hydrophilic and lipophilic antioxidant capacities ranged from 64.6 to 80 mg of gallic acid equivalent/100 g seed; from 0.07 to 0.09 mg of β-carotene equivalent/100 g of seed; from 4.3 to 7.3 and, from 1.0 to 2.8 μmol of Trolox equivalent/g of seed, respectively, among the evaluated SI cultivars. Results showed significant differences (p < 0.05) among the evaluated SI cultivars in the contents of ω3, ω6, antioxidant capacities and other evaluated phytochemicals. SI seeds should be considered as an important dietary source of health promoting phytochemicals.     

Antioxidant properties of different cultivars of Portulaca oleracea

Methanolic extracts of six cultivars of Portulaca oleracea were analyzed for their total phenol content (TPC) using the Folin–Ciocalteu method. The antioxidant activity was measured using the 1,1-diphenyl-2-picrylhydrazyl, ferric-reducing antioxidant power (FRAP) and β-carotene bleaching (BCB) assays. The iodine titration method was used to determine the ascorbic acid content (AAC). The TPC of the cultivars of P. oleracea ranged from 127 ± 13 to 478 ± 45 mg GAE/100 g of fresh weight of plant. There was good correlation between the TPC value and its AEAC, IC₅₀ and FRAP values (r² > 0.9) for all the cultivars. The AAC for the cultivars ranged from 38.5 ± 0.6 to 73.0 ± 17.5 mg/100 g. The TPC value of the common variety PO1, was the lowest compared to the ornamental cultivars (PO2–PO6). The BCB assay showed that all cultivars were capable of inhibiting lipid peroxidation and the inhibition power did not correlate with TPC value.     

Survey of Salmonella contamination of edible nut kernels on retail sale in the UK

Consumption of nut kernels has shown an upward trend due to people's increasing tendency to eat healthy snacks. The purpose of this survey was to establish the microbiological safety of retail edible nut kernel samples of different varieties. Overall Salmonella spp. and Escherichia coli were detected from 0.1% and 0.8% of 2886 edible nut kernels, respectively. S. Senftenberg and S. Tennessee were detected from two pre-packed samples of Brazil nuts (0.4%) and S. Anatum from a pre-packed mixed nuts sample (0.9%; mix: almonds, Brazils, cashews, peanuts, walnuts) indicating a risk to health. The levels of Salmonella ranged from <0.01 to 0.23/g. E. coli at unsatisfactory levels (150/g) was present in another pre-packed Brazils nuts sample (0.2%). E. coli was additionally found at lower levels (range: 3.6–43/g) in Brazils (1.9%), macadamia (1.5%), pistachios (1.1%), walnuts (0.7%), peanuts (0.7%), hazels (0.5%), cashews (0.4%), and almonds (0.3%). Levels of E. coli did not correlate with the presence of Salmonella. The batches contaminated with Salmonella were recalled and Food Standards Agency food alerts were issued to advise against the consumption of the affected products. The presence of Salmonella is unacceptable in ready-to-eat foods and follows that the need for applying good agricultural and hygiene practices and effective decontamination procedures during the production of edible kernels cannot be overemphasized.     

Chemical composition,antimicrobial, cytotoxic and antioxidant activities of the essential oil of Artemisia indica Willd

Essential oil from the aerial parts of Artemisia indica was analysed by GC-FID and GC–MS. A total of 43 compounds representing 96.8% of the oil were identified and the major components were found to be artemisia ketone (42.1%), germacrene B (8.6%), borneol (6.1%) and cis-chrysanthenyl acetate (4.8%). Antimicrobial activity of the oil was evaluated against seven clinically significant bacterial and two fungal strains. The essential oil and its major constituents exhibited moderate to potent, broad-spectrum antibacterial and antifungal activities targeting both Gram-positive and Gram-negative bacteria. In vitro cytotoxicity evaluation against four human cancer cell lines THP-1 (leukemia), A-549 (lung), HEP-2 (liver) and Caco-2 (colon) showed that the essential oil exhibited concentration dependant growth inhibition in the 10–100 μg/ml dilution range, with IC₅₀ values of 10 μg/ml (THP-1), 25 μg/ml (A-549), 15.5 μg/ml (HEP-2) and 19.5 μg/ml (Caco-2). It was interesting to note that the essential oil also exhibited potent antioxidant activity.     

Phenolic composition,antioxidant and acetylcholinesterase inhibitory activities of Sclerocarya birrea and Harpephyllum caffrum (Anacardiaceae) extracts

Total phenolic content, proanthocyanidins, gallotannins, flavonoids, and antioxidant activities of Sclerocarya birrea and Harpephyllum caffrum methanolic extracts were evaluated using in vitro assays. S. birrea young stem extract contained the highest levels of total phenolic content (14.15 ± 0.03 mg GAE/g), flavonoids (1.21 ± 0.01 mg CE/g) and gallotannins (0.24 ± 0.00 mg GAE/g). H. caffrum stem bark extract had the highest content of proanthocyanidins (1.47%). The EC₅₀ values of the extracts in the DPPH free radical scavenging assay ranged from 4.26 to 6.92 μg/ml, compared to 6.86 μg/ml for ascorbic acid. A dose-dependent linear curve was obtained for all extracts in the ferric-reducing power assay. Dichloromethane and methanol extracts exhibited dose-dependent acetylcholinesterase inhibitory activity. Similarly, all extracts exhibited high antioxidant activity comparable to butylated hydroxytoluene based on the rate of β-carotene bleaching (84.1–93.9%). The two Anacardiaceae species provide a source of natural antioxidants and acetylcholinesterase inhibitors, and may be beneficial to the health of consumers.     

Antibacterial labdane diterpenoids of Ulva fasciata Delile from southwestern coast of the Indian Peninsula

Chromatographic purification of the dichloromethane-soluble fraction of alga, on neutral alumina, using increasing concentrations of ethylacetate/n-hexane as eluents, yielded seven labdane diterpenoids (1–7) as major constituents of green alga Ulva fasciata. Structures of these diterpenoids were established using extensive spectroscopic techniques. Antimicrobial assay showed that the compounds labda-14-ene-3α,8α-diol (2) and labda-14-ene-8α-hydroxy-3-one (4) were inhibitory to the growth of Vibrio parahaemolyticus and Vibrio alginolyticus with minimum inhibitory concentrations of 30 μg/ml by 2, and 40 μg/ml by 4, respectively against the former and 30 μg/ml by 2, and 80 μg/ml by 4, respectively, against the latter. Structure–activity relationship analyses revealed that the compounds with electronegative hydroxyl or carbonyl group(s) exhibit greater activities, apparently by proton exchange reaction with the basic aminoacyl residue at the macromolecular receptor site of virulent enzymes of pathogenic bacteria. These might provide promising therapeutic agents against infections with multi-resistant Gram-negative fish pathogenic bacteria.     

Catechin and epicatechin in testa and their association with bioactive compounds in kernels of cashew nut (Anacardium occidentale L.)

Catechins in testa and bioactive compounds in testa-free and testa-containing kernels of cashew nuts were analysed. The cashew nut testa contained (+)-catechin and (−)-epicatechin with concentrations of 5.70 and 4.46 g per kg DM, respectively. Testa-containing kernels revealed significantly higher levels of β-carotene (218 vs. 89.6 μg/kg DM), lutein (525 vs. 292 μg/kg DM), and α-tocopherol (10.1 vs. 2.4 mg/kg DM), similar amounts of zeaxanthin (7.0 vs. 7.1 μg/kg DM), γ-tocopherol (10.6 vs. 10.1 mg/kg DM), stearic acid (41 vs. 43 g/kg DM), oleic acid (214 vs. 219 g/kg DM) and linoleic acid (69 vs. 62 g/kg DM), but a lower concentration of thiamine (3.0 vs. 10.7 mg/kg DM) in comparison to testa-free samples. The testa-containing kernels provide high amounts of catechins and higher concentrations of β-carotene, lutein and α-tocopherol than do testa-free cashew nut kernels. This could have potential health benefits for consumers.     

Effect of refining processes on antioxidant capacity,total contents of phenolics and carotenoids in palm oils

Antioxidant capacity (AC), total phenolic content (TPC) and total carotenoid content (TCC) in palm oils at various stages of the refining process from two technological modes were determined. The obtained mean FRAP and DPPH values for the methanolic extracts of palm oils from mode 1 (19.5–102.8 μmol TE/100 g and 18.8–103.0 μmol TE/100 g) were lower than for oils from mode 2 (25.6–134.8 μmol TE/100 g and 25.4–135.4 μmol TE/100 g). The total phenolics (4.1–12.4 mg GA/100 g) and carotenoids (0.18–45.8 mg/100 g) in the studied oils were correlated with their antioxidant capacities determined by FRAP and DPPH methods (r = 0.6623–0.9878). During the refining process, for both technological modes resulted in a loss of AC by 80%, TPC by 26–55% and TCC by 99%. The bleaching step caused the highest losses of AC as determined by FRAP 41% and 46%, DPPH by 43% and 48%, while TPC loss was 45% and 23% and loss of carotenoids was 49% and 56%, in mode 1 and mode 2, respectively.     

Functional properties of protein concentrates and isolates produced from cashew (Anacardium occidentale L.) nut

Protein isolates and concentrates were obtained from defatted cashew nut powder by two methods: alkaline extraction-isoelectric precipitation (IP) and alkaline extraction-methanol precipitation (MP). The functional properties of cashew nut protein isolates, concentrates and powder were significantly different (p < 0.05). Cashew nut protein isolate (CNPI) had higher water and oil absorption capacities (2.20 ml/g and 4.42 ml/g, respectively), emulsifying stability index (447%), foam capacity and stability (45% and 55%, respectively), and least gelation capacity (13.5%) than cashew nut protein concentrate (CNPC), which was also higher than that of defatted cashew nut powder (DCNP). However, emulsifying activity index (12.45%) and bulk density (0.31) of CNPI were lower than that of CNPC, which were also lower than that of DCNP. The water solubility of CNPI (95%) and CNPC (95%) was not significantly different (p > 0.05) among the samples, but was significantly different (p < 0.05) from that of DCNP (75%). The CNPI, CNPC and DCNP showed decreasing solubility with decreasing pH, with the minimum solubility being observed at a pH range of 4.0–4.5, confirming the isoelectric point of cashew proteins. However, higher water solubility, emulsifying activity, and foaming property were observed at an alkaline pH than at an acidic pH in all samples.     

Phytochemical constituents and antioxidant capacity of different pecan [Carya illinoinensis (Wangenh.) K. Koch] cultivars

Six pecan cultivars were analyzed for their antioxidant capacity (AC), total phenolics (TP), condensed tannin (CT), HPLC phenolic profile, tocopherol and fatty acid composition. Kernels which included the outer brown testa or pellicle, and shells which is the hard cover that surrounds the kernel, were evaluated for each cultivar. Strong correlations were found in kernels between AC and TP for both DPPH (r² = 0.98) and AC_ORAC (r² = 0.75) antioxidant assays. AC_ORAC values ranged from 372 to 817 μmol trolox equivalents/g defatted kernel, corresponding to Desirable and Kanza cultivars, respectively. CT ranged from 23 to 47 mg catechin equivalents/g defatted kernel and TP from 62 to 106 mg of chlorogenic acid equivalents/g defatted kernel. After a consecutive basic-acid hydrolysis, gallic acid, ellagic acid, catechin and epicatechin were identified by HPLC. The TP, AC and CT were 6, 4.5 and 18 times higher, respectively, for shells compared to kernels. The presence of phenolic compounds with high antioxidant capacity in kernels and shells indicates pecans can be considered an important dietary source of antioxidants.     

Identification,characterisation, and quantification of phenolic compounds in the antioxidant activity-containing fraction from the seeds of Korean perilla (Perilla frutescens) cultivars

The present research was the first to investigate phenolic compound profiles and antioxidant properties in the seeds of various perilla (Perilla frutescens) cultivars. The 80% methanol extract (50 μg/ml) of this species showed potent antioxidant activities against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radicals. Phenolic compounds were characterised by nuclear magnetic resonance (NMR) spectroscopy, and ultra performance liquid chromatography with photodiode array detector and electrospray ionisation/mass (UPLC-PDA-ESI/MS) analysis. Nine compounds were elucidated as caffeic acid-3-O-glucoside (1), caffeic acid (2), luteolin-7-O-glucoside (3), apigenin-7-O-glucoside (4), rosmarinic acid-3-O-glucoside (5), rosmarinic acid (6), luteolin (7), apigenin (8), and chrysoeriol (9). The individual and total phenolic contents were remarkably different, especially rosmarinic acid-3-O-glucoside (5) and rosmarinic acid (6) which were the predominant compounds (>95%) in all perilla cultivars. Additionally, Yeupsil cultivar exhibited the highest phenolic content (5029.0 μg/g) and antioxidant activity, whereas the lowest was shown by Dasil (2138.7 μg/g). Therefore, these results suggest that antioxidant effects of perilla seeds are correlated with phenolic contents.     

Evaluation of antioxidant property of extract and fractions obtained from a red alga, Polysiphonia urceolata

Antioxidant activity (AA), total phenolic content, and reducing power of the crude extract, fractions, and subfractions derived from a red alga, Polysiphonia urceolata, were evaluated and determined. The antioxidative activity was measured using the α,α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging assay and the β-carotene–linoleate assay systems, and compared with that of butylated hydroxytoluene (BHT), gallic acid (GA), and ascorbic acid (AscA). The results showed that the crude extract and the ethyl acetate-soluble fraction exhibited higher AA than BHT in the DPPH assay model, at all of four concentration levels tested (from 0.4 to 50 μg/ml), while, in the β-carotene–linoleate assay system, the crude extract and the ethyl acetate-soluble fraction exhibited similar or, in most cases, higher AA than GA and AscA at the same concentrations (from 10 to 200 μg/ml). The ethyl acetate-soluble fraction was further fractionated into seven subfractions F1–F7 by silica gel vacuum liquid chromatography. F1 was found to be the most effective subfraction in both assay systems. The total phenolic content and reducing power were determined using the Folin–Ciocalteu and the potassium ferricyanide reduction methods, respectively. Statistical analysis indicated a significant association between the antioxidant potency and total phenolic content as well as between the antioxidant potency and reducing power.     

Antioxidant and free radical scavenging activities of polyphenol-enriched curry leaf (Murraya koenigii L.) extracts

The in vitro antioxidant properties of different extracts (water, alcohol, alcohol:water, hexane or chloroform extract) of curry leaves (Murraya koenigii L.) were evaluated using various assays. The alcohol:water (1:1) extract of curry leaves (AWEC) showed the highest antioxidant and free radical scavenging activity. It inhibited membrane lipid peroxidation by 76%, at 50 μg/ml, scavenged 93% of superoxides at 200 μg/3 ml and scavenged approximately 90% of hydroxyl and 1,1-diphenyl-2-picrylhydrazayl radicals at 4–5-fold lower concentrations compared to the other tested extracts. In addition, the alcohol:water extract reduced cytochrome c and ferric ion levels, chelated ferrous ions and inhibited ferrous sulfate:ascorbate-induced fragmentation and sugar oxidation of DNA. These results establish the antioxidant potential of AWEC, which could be used as natural antioxidant source.     

Antioxidant activity and phenolic content of 16 raisin grape (Vitis vinifera L.) cultivars and selections

Six raisin grape cultivars and 10 new raisin grape selections were analyzed for antioxidant activity (ABTS assay) and for total and individual phenolic compounds. Samples were freeze–dried and values are reported on a dry weight basis. Antioxidant activity across the 16 samples ranged from 7.7 to 60.9 μmol Trolox/g DW, with A95-27 exhibiting the greatest activity. Total phenolic content, determined in gallic acid equivalents using the Folin–Ciocalteau assay, ranged from 316.3 to 1141.3 mg gallic acid/100 g DW and was strongly correlated (r = 0.990) with antioxidant results. Concentrations of individual phenolics were determined by HPLC. trans-Caftaric acid was the predominant compound in all samples. A95-15 contained the lowest concentration (153.5 μg/g DW) of caftaric acid, while Fiesta contained the highest concentration (598.7 μg/g DW). Selections A56-66, A95-15, and A95-27 had much higher levels of catechin (86.5–209.1 μg/g DW) and epicatechin (126.5–365.7 μg/g DW) than the other samples.