Extraction, identification, and quantification of antioxidant phenolics from hazelnut (Corylus avellana L.) shells.
Hazelnut shells are the major byproduct of the hazelnut industry. The objectives of this study were to optimize the conditions for extracting phenolics and to identify and quantify the phenolics in hazelnut shells. Preliminary optimization showed that a high recovery of phenolics could be achieved with shell particle size less than 0.5mm when extracted with acetone at 50°C. Response surface experiments showed that a 10g/l liquid to solid ratio, 58% acetone, and 12h extraction time yielded the highest amount of phenolics. Twenty-seven phenolic compounds were identified in hazelnut shells by mass spectrometry. Coumaroylquinic acid, epicatechin gallate, quercetin, and six other phenolics were identified in hazelnut shells for the first time. The most abundant phenolics in hazelnut shells were catechin, epicatechin gallate, and gallic acid, as quantified by high performance liquid chromatography (HPLC). These results can be useful for the development of industrial extraction processes of natural antioxidants from hazelnut shells.
Food allergen detection by mass spectrometry: the role of systems biology.
Food allergy prevalence is rising worldwide, motivating the development of assays that can sensitively and reliably detect trace amounts of allergens in manufactured food. Mass spectrometry (MS) is a promising alternative to commonly employed antibody-based assays owing to its ability to quantify multiple proteins in complex matrices with high sensitivity. In this review, we discuss a targeted MS workflow for the quantitation of allergenic protein in food products that employs selected reaction monitoring (SRM). We highlight the aspects of SRM method development unique to allergen quantitation and identify opportunities for simplifying the process. One promising avenue identified through a comprehensive survey of published MS literature is the use of proteotypic peptides, which are peptides whose presence appears robust to variations in food matrix, sample preparation protocol, and MS instrumentation. We conclude that proteotypic peptides exist for a subset of allergenic milk, egg, and peanut proteins. For less studied allergens such as soy, wheat, fish, shellfish, and tree nuts, we offer guidance and tools for peptide selection and specificity verification as part of an interactive web database, the Allergen Peptide Browser (http://www.AllergenPeptideBrowser.org). With ongoing improvements in MS instrumentation, analysis software, and strategies for targeted quantitation, we expect an increasing role of MS as an analytical tool for ensuring regulatory compliance.
Dietary dried plum increases bone mass, suppresses proinflammatory cytokines and promotes attainment of peak bone mass in male mice.
Nutrition is an important determinant of bone health and attainment of peak bone mass. Diets containing dried plum (DP) have been shown to increase bone volume and strength. These effects may be linked to the immune system and DP-specific polyphenols. To better understand these relationships, we studied DP in skeletally mature (6-month-old) and growing (1- and 2-month-old) C57Bl/6 male mice. In adult mice, DP rapidly (<2 weeks) increased bone volume (+32%) and trabecular thickness (+24%). These changes were associated with decreased osteoclast surface (Oc.S/BS) and decreased serum CTX, a marker of bone resorption. The reduction in Oc.S/BS was associated with a reduction in the osteoclast precursor pool. Osteoblast surface (Ob.S/BS) and bone formation rate were also decreased suggesting that the gain in bone in adult mice is a consequence of diminished bone resorption and formation, but resorption is reduced more than formation. The effects of DP on bone were accompanied by a decline in interleukins, TNF and MCP-1, suggesting that DP is acting in part through the immune system to suppress inflammatory activity and reduce the size of the osteoclast precursor pool. Feeding DP was accompanied by an increase in plasma phenolics, some of which have been shown to stimulate bone accrual. In growing and young adult mice DP at levels as low as 5% of diet (w/w) increased bone volume. At higher levels (DP 25%), bone volume was increased by as much as 94%. These data demonstrate that DP feeding dramatically increases peak bone mass during growth.
A systematic review on the health effects of plums (Prunus domestica and Prunus salicina).
In recent times, plums have been described as foods with health-promoting properties. Research on the health effects of plum continue to show promising results on its antiinflammatory, antioxidant and memory-improving characteristics. The increased interest in plum research has been attributed to its high phenolic content, mostly the anthocyanins, which are known to be natural antioxidants. A systematic review of literature was carried out to summarize the available evidence on the impact of plums (Prunus species; domestica and salicina) on disease risk factors and health outcomes. A number of databases were searched according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for relevant studies on plum health effects in vitro, animal studies and clinical trials. A total of 73 relevant peer-reviewed journal articles were included in this review. The level of evidence remains low. Of the 25 human studies, 6 were confirmatory studies of moderate quality, while 19 were exploratory. Plums have been shown to possess antioxidant and antiallergic properties, and consumption is associated with improved cognitive function, bone health parameters and cardiovascular risk factors. Most of the human trials used the dried version of plums rather than fresh fruit, thus limiting translation to dietary messages of the positioning of plums in a healthy diet. Evidence on the health effect of plums has not been extensively studied, and the available evidence needs further confirmation.
The effect of microwave roasting on the antioxidant properties of the Bangladeshi groundnut cultivar.
BACKGROUND: Groundnut seeds are an important source of bioactive phenolic compounds with noteworthy antioxidant capacity, which may be enhanced by the microwave roasting process. The aim of this work is to study the changes in antioxidant activity in groundnut seeds during microwave roasting, as a function of roasting time and extract concentration, in order to maximise the phenolic content and antioxidant activity of roasted seeds. METHODS: The study was conducted to evaluate total phenolic content (TPC), total flavonoid content (TFC), and antioxidative activity of methanolic (GME), ethanolic (GEE), and chloroform (GCE) extracts and methanolic extract of oil (GMO) from groundnut seeds exposed to microwaves. The antioxidant activity was investigated using several assays, namely phosphomolybdenum assay, DPPH radical scavenging activity, H2O2 scavenging activity, hydroxyl radical scavenging activity and reducing power. RESULTS: The microwave roasting process significantly increased the TPC, whilst the TFC decreased with roasting time. Antioxidant activity increased with increased roasting time and extract concentration in all extracts. Antioxidant activity increased significantly at lower concentrations; however, the rate of increment decreased gradually as the concentration of the solvent extract increased. Thus, among all the extracts, methanol extracts at all roasting times and extract concentrations appeared to display the highest effectiveness. The various scavenging activities of the samples are ranked in the following order: GME > GEE > GCE > GMO, in both raw and roasted samples. CONCLUSIONS: Both roasting time and extract concentration were found to be critical factors in determining the overall quality of the product. This investigation is important to determine optimum roasting conditions, in order to maximise the anti-oxidative health benefits of the Bangladeshi groundnut cultivar.
Reduction of Bacterial Pathogens and Potential Surrogates on the Surface of Almonds Using High-Intensity 405-Nanometer Light.
The disinfecting properties of high-intensity monochromatic blue light (MBL) were investigated against Escherichia coli O157:H7, Salmonella , and nonpathogenic bacteria inoculated onto the surface of almonds. MBL was generated from an array of narrow-band 405-nm light-emitting diodes. Almonds were inoculated with higher or lower levels (8 or 5 CFU/g) of pathogenic E. coli O157:H7 and Salmonella , as well as nonpathogenic E. coli K-12 and an avirulent strain of Salmonella Typhimurium, for evaluation as potential surrogates for their respective pathogens. Inoculated almonds were treated with MBL for 0, 1, 2, 4, 6, 8, and 10 min at a working distance of 7 cm. Simultaneous to treatment, cooling air was directed onto the almonds at a rate of 4 ft3/min (1.89 ×10-3 m3/s), sourced through a container of dry ice. An infrared camera was used to monitor the temperature readings after each run. For E. coli K-12, reductions of up to 1.85 or 1.63 log CFU/g were seen for higher and lower inoculum levels, respectively; reductions up to 2.44 and 1.44 log CFU/g were seen for E. coli O157:H7 (higher and lower inoculation levels, respectively). Attenuated Salmonella was reduced by up to 0.54 and 0.97 log CFU/g, whereas pathogenic Salmonella was reduced by up to 0.70 and 0.55 log CFU/g (higher and lower inoculation levels, respectively). Inoculation level did not significantly impact minimum effective treatment times, which ranged from 1 to 4 min. Temperatures remained below ambient throughout treatment, indicating that MBL is a nonthermal antimicrobial process. The nonpathogenic strains of E. coli and Salmonella each responded to MBL in a comparable manner to their pathogenic counterparts. These results suggest that these nonpathogenic strains may be useful in experiments with MBL in which a surrogate is required, and that MBL warrants further investigation as a potential antimicrobial treatment for low-moisture foods.
Survival Kinetics of Salmonella enterica and Enterohemorrhagic Escherichia coli on a Plastic Surface at Low Relative Humidity and on Low–Water Activity Foods.
We investigated the survival kinetics of Salmonella enterica and enterohemorrhagic Escherichia coli under various water activity (aw) conditions to elucidate the net effect of aw on pathogen survival kinetics and to pursue the development of a predictive model of pathogen survival as a function of aw. Four serotypes of S. enterica (Stanley, Typhimurium, Chester, and Oranienburg) and three serotypes of enterohemorrhagic E. coli ( E. coli O26, E. coli O111, and E. coli O157:H7) were examined. These bacterial strains were inoculated on a plastic plate surface at a constant relative humidity (RH) (22, 43, 58, 68, or 93% RH, corresponding to the aw) or on a surface of almond kernels (aw 0.58), chocolate (aw 0.43), radish sprout seeds (aw 0.58), or Cheddar cheese (aw 0.93) at 5, 15, or 25°C for up to 11 months. Under most conditions, the survival kinetics were nonlinear with tailing regardless of the storage aw, temperature, and bacterial strain. For all bacterial serotypes, there were no apparent differences in pathogen survival kinetics on the plastic surface at a given storage temperature among the tested RH conditions, except for the 93% RH condition. Most bacterial serotypes were rapidly inactivated on Cheddar cheese when stored at 5°C compared with their inactivation on chocolate, almonds, and radish sprout seeds. Distinct trends in bacterial survival kinetics were also observed between almond kernels and radish sprout seeds, even though the aws of these two foods were not significantly different. The survival kinetics of bacteria inoculated on the plastic plate surface showed little correspondence to those of bacteria inoculated on food matrices at an identical aw. Thus, these results demonstrated that, for low-aw foods and/or environments, aw alone is insufficient to account for the survival kinetics of S. enterica and enterohemorrhagic E. coli.
Evaluation the effect of gamma irradiation on microbial, chemical and sensorial properties of peanut (Arachis hypogaea l.) seeds.
BACKGROUND: The aim of the present study was to evaluate the possibility to apply gamma radiation treatment for decontaminating and assuring the quality of peanut seeds. METHODS: The radiation processing was carried out at dose levels of 3, 6 and 9 kGy. The irradiated and non-irradiated (control) samples were stored at room temperature for 12 months, and analyzed for microbial load, proximate composition, sensorial acceptance and chemical properties. RESULTS: The results indicated that gamma irradiation treatment significantly (p < 0.05) reduced microbial load and enhanced the safety of the irradiated samples. The irradiated samples were also acceptable sensorically. The total acidity and total volatile nitrogen (TVBN) contents increased with the increase of radiation dose. Furthermore, in general, no substantial change in proximate constituents was observed amongst the samples. No significant (p > 0.05) differences in the taste, flavor, color and texture score were observed among treatments (0, 3, 6 and 9 kGy). CONCLUSIONS: Irradiation protected again bacterial and fungal growth and retained the nutritional components of samples during long-term storage.