Static Hot Air and Infrared Rays Roasting are Efficient Methods for Aflatoxin Decontamination on Hazelnuts.
Aflatoxins are a group of secondary metabolites produced by members of Aspergillus Section Flavi that are dangerous to humans and animals. Nuts can be potentially contaminated with aflatoxins, often over the legal threshold. Food processes, including roasting, may have different effects on mycotoxins, and high temperatures have proven to be very effective in the reduction of mycotoxins. In this work, two different roasting methods-traditional static hot air roasting and infra-red rays roasting-were applied and compared for the detoxification of hazelnuts from Italy and Turkey. At the temperature of 140 °C for 40 min of exposure, detoxification was effective for both roasting techniques. Residual aflatoxins after infra-red rays treatments were lower compared to static hot air roasting. On Italian hazelnuts, residual aflatoxins were lower than 5%, while for Turkish hazelnuts they were lower than 15% after 40 min of exposure to an infra-red rays roaster. After roasting, the perisperm was detached from the nuts and analyzed for aflatoxin contents. Residual aflatoxins in the perisperm ranged from 80% up to 100%. After roasting, the lipid profile and the nutritional quality of hazelnuts were not affected. Fatty acid methyl esters analyses showed a similar composition for Italian and Turkish hazelnuts.
Comparing Thermal Process Validation Methods for Salmonella Inactivation on Almond Kernels.
Ongoing regulatory changes are increasing the need for reliable process validation methods for pathogen reduction processes involving low-moisture products; however, the reliability of various validation methods has not been evaluated. Therefore, the objective was to quantify accuracy and repeatability of four validation methods (two biologically based and two based on time-temperature models) for thermal pasteurization of almonds. Almond kernels were inoculated with Salmonella Enteritidis phage type 30 or Enterococcus faecium (NRRL B-2354) at ~108 CFU/g, equilibrated to 0.24, 0.45, 0.58, or 0.78 water activity (aw), and then heated in a pilot-scale, moist-air impingement oven (dry bulb 121, 149, or 177°C; dew point <33.0, 69.4, 81.6, or 90.6°C; vair = 2.7 m/s) to a target lethality of ~4 log. Almond surface temperatures were measured in two ways, and those temperatures were used to calculate Salmonella inactivation using a traditional (D, z) model and a modified model accounting for process humidity. Among the process validation methods, both methods based on time-temperature models had better repeatability, with replication errors approximately half those of the surrogate ( E. faecium ). Additionally, the modified model yielded the lowest root mean squared error in predicting Salmonella inactivation (1.1 to 1.5 log CFU/g); in contrast, E. faecium yielded a root mean squared error of 1.2 to 1.6 log CFU/g, and the traditional model yielded an unacceptably high error (3.4 to 4.4 log CFU/g). Importantly, the surrogate and modified model both yielded lethality predictions that were statistically equivalent (α = 0.05) to actual Salmonella lethality. The results demonstrate the importance of methodology, aw, and process humidity when validating thermal pasteurization processes for low-moisture foods, which should help processors select and interpret validation methods to ensure product safety.
Impact of processing conditions on the phytoprostanes profile of three types of nut kernels.
The goal of this work was the identification and quantification of phytoprostanes (PhytoPs) in three types of nuts: "Walnut", "Macadamia", and "Pecan". This study represents a first approach to the relationship between the quantitative and qualitative PhytoP profiles in the "Macadamia" and "Pecan" nuts subjected to fried salt or fried honey processing. The kernels were found to contain 9-F1t-PhytoP, 9-epi-9-F1t-PhytoP, 16-B1-PhytoP, ent-16-B1-PhytoP, 9-L1-PhytoP, and ent-9-L1-PhytoP. "Macadamia" fried salt nuts were the only ones that produced 9-epi-9-D1-PhytoP and 9-D1-PhytoP. The total PhytoP concentration in raw nuts was in the range of 5541-7830 ng kg-1 fresh weight (FW); for most of the PhytoPs, the concentrations were lowest in raw walnuts, indicating that concentration of each PhytoP was influenced by the genotype. The frying process increased the total PhytoPs concentration to the range of 8903-33,727 ng kg-1 FW. Therefore, this is the first work describing PhytoPs in nuts and reinforces the capacity of these compounds to act as biomarkers to monitor the processing treatments that influence the final quality of nuts.
Influence of controlled atmosphere on thermal inactivation of Escherichia coli ATCC 25922 in almond powder.
Heat controlled atmosphere (CA) treatments hold potential to pasteurize Salmonella enteritidis PT 30 in almonds. Nonpathogenic Escherichia coli ATCC 25922 was used as a surrogate species of pathogenic Salmonella for validation of thermal pasteurization to meet critical safety requirements. A controlled atmosphere/heating block system (CA-HBS) was used to rapidly determine thermal inactivation of E. coli ATCC 25922. D- and z-values of E. coli ATCC 25922 inoculated in almond powder were determined at four temperatures between 65 °C and 80 °C under different gas concentrations and heating rates. The results showed that D- and z-values of E. coli under CA treatment were significantly (P < 0.05) lower than those under regular atmosphere (RA) treatment at 4 given temperatures. Relatively higher CO2 concentrations (20%) and lower O2 concentrations (2%) were more effective to reduce thermal inactivation time. There were no significant differences in D-values of E. coli when heating rates were above 1 °C/min both in RA and CA treatments. But D-values significantly (P < 0.05) increased under RA treatment and decreased under CA treatment at lower heating rates. Combination of rapid heat and CA treatments could be a promising method for thermal inactivation of S. enteritidis PT 30 in almond powder.
Rapid Characterization of Trace Aflatoxin B1 on Groundnuts, wheat and maize by Dispersive Liquid‐Liquid Microextraction Followed by Direct Electrospray Probe Tandem Mass Spectrometry.
RATIONALE: Aflatoxins are poisonous and cancer-related chemical compounds commonly existed in crops and plants. Aflatoxin B1 is the most toxic compound among aflatoxins and has been classified as Group 1 carcinogenic to human, especially on liver cancer. Herein, an ambient mass spectrometric method was developed for rapid characterization of trace aflatoxin B1 on peanuts. METHODS: Direct electrospray probe tandem mass spectrometry was used to detect aflatoxin B1 on peanuts. To avoid the matrix effect, the aflatoxin B1 in the samples was extracted and concentrated by dispersive liquid-liquid microextraction. The mass spectrometer was operated in the positive ion mode to monitor intact molecular ion (m/z 313, MH+ ) and daughter ion (m/z 241) of aflatoxin B1 using multiple reaction monitoring. RESULTS: Since no clean up procedure of the sample was required, the sampling step, and the subsequent mass spectrometric detection of the aflatoxin B1 was completed less than 5 minutes. The limit-of-detection of aflatoxin B1 is at sub-ppb level. The results obtained by direct electrospray probe tandem mass spectrometry were also validated by liquid chromatography-tandem mass spectrometry. Recovery of aflatoxin B1 in the sample was evaluated by analyzing spiked aflatoxin B1 with liquid chromatography-tandem mass spectrometry to be 85% and direct electrospray probe tandem mass spectrometry to be 84%. CONCLUSION: The direct electrospray probe tandem mass spectrometry combined with a simple dispersive liquid-liquid microextraction procedure was successfully used for the quantitative analysis of AFB1 in nut samples. Due to its highly efficient feature, it is promising in providing important toxicological information for food safety in real world.
Mediterranean Diet Improves High-Density Lipoprotein Function in High-Cardiovascular-Risk Individuals: A Randomized Controlled Trial.
BACKGROUND: The biological functions of high-density lipoproteins (HDLs) contribute to explaining the cardioprotective role of the lipoprotein beyond quantitative HDL cholesterol levels. A few small-scale interventions with a single antioxidant have improved some HDL functions. However, to date, no long-term, large-scale, randomized controlled trial has been conducted to assess the effects of an antioxidant-rich dietary pattern (such as a traditional Mediterranean diet [TMD]) on HDL function in humans. METHODS: This study was performed in a random subsample of volunteers from the PREDIMED Study (Prevención con Dieta Mediterránea; n=296) after a 1-year intervention. We compared the effects of 2 TMDs, one enriched with virgin olive oil (TMD-VOO; n=100) and the other enriched with nuts (TMD-Nuts; n=100), with respect to a low-fat control diet (n=96). We assessed the effects of both TMDs on the role of HDL particles on reverse cholesterol transport (cholesterol efflux capacity, HDL ability to esterify cholesterol, and cholesteryl ester transfer protein activity), HDL antioxidant properties (paraoxonase-1 arylesterase activity and total HDL antioxidant capacity on low-density lipoproteins), and HDL vasodilatory capacity (HDL ability to induce the release of nitric oxide in endothelial cells). We also studied the effects of a TMD on several HDL quality-related characteristics (HDL particle oxidation, resistance against oxidative modification, main lipid and protein composition, and size distribution). RESULTS: Both TMDs increased cholesterol efflux capacity relative to baseline (P=0.018 and P=0.013 for TMD-VOO and TMD-Nuts, respectively). The TMD-VOO intervention decreased cholesteryl ester transfer protein activity (relative to baseline, P=0.028) and increased HDL ability to esterify cholesterol, paraoxonase-1 arylesterase activity, and HDL vasodilatory capacity (relative to control, P=0.039, P=0.012, and P=0.026, respectively). Adherence to a TMD induced these beneficial changes by improving HDL oxidative status and composition. The 3 diets increased the percentage of large HDL particles (relative to baseline, P<0.001). CONCLUSIONS: The TMD, especially when enriched with virgin olive oil, improved HDL atheroprotective functions in humans.
Potential prebiotic properties of cashew apple (Anacardium occidentale L.) agro‐industrial byproduct on Lactobacillus species.
BACKGROUND: The prebiotic effects of a cashew apple (Anacardium occidentale L.) agro-industrial byproduct powder (CAP) on different potentially probiotic Lactobacillus strains, namely L. acidophilus LA-05, L. casei L-26 and L. paracasei L-10, was assessed using in vitro experimental models. For this, the growth of the Lactobacillus strains when cultivated in a broth containing CAP (20 or 30 g L-1 ), glucose (20 g L-1 ) or fructooligosaccharides (FOS) (20 g L-1 ) were monitored during 48 h; the prebiotic activity scores of CAP were determined; and the changes in pH values, production of organic acids and consumption of sugars in growth media were verified. RESULTS: During the 48 h-cultivation, similar viable cell counts were observed for the Lactobacillus strains grown in the different tested media. The CAP presented positive prebiotic activity scores toward all the tested Lactobacillus strains, indicating a desirable selective fermentable activity relative to enteric organisms. The cultivation of the Lactobacillus strains in broth containing glucose, FOS or CAP resulted in high viable cell counts, decreased pH, production of organic acids and consumption of sugars over time, revealing intense bacterial metabolic activity. CONCLUSION The CAP exert potential prebiotic effects on different potentially probiotic Lactobacillus strains, and should be an added-value ingredient for food industry.
Effects of almond consumption on the post-lunch dip and long-term cognitive function in energy-restricted overweight and obese adults.
The post-lunch dip in cognition is a well-established phenomenon of decreased alertness, memory and vigilance after lunch consumption. Lunch composition reportedly influences the post-lunch dip. Moreover, dieting is associated with cognitive function impairments. The negative effects of dieting have been reversed with nut-supplemented diets. The aims of this study were to (1) evaluate the acute effect of an almond-enriched high-fat lunch or high-carbohydrate lunch on the post-lunch decline in cognitive function, and (2) evaluate the effects of chronic almond consumption as part of an energy-restricted diet on the memory and attention domains of cognitive function. In total, eighty-six overweight and obese adults were randomised to consume either an almond-enriched diet (AED) or a nut-free control diet (NFD) over a 12-week weight loss intervention. Participants were also randomised to receive either an almond-enriched high-fat lunch (A-HFL) (>55 % energy from fat, almonds contributing 70-75 % energy) or a high-carbohydrate lunch (HCL) (>85 % energy from carbohydrates) at the beginning and end of the weight loss intervention. Memory and attention performance indices decreased after lunch consumption (P<0·001). The A-HFL group ameliorated the decline in memory scores by 57·7 % compared with the HCL group (P=0·004). Both lunch groups had similar declines in attention. Moreover, memory and attention performance indices increased after the 12-week intervention period (P<0·05) with no difference between the AED and NFD groups. In conclusion, almond consumption at a midday meal can reduce the post-lunch dip in memory. However, long-term almond consumption may not further improve cognitive function outcomes in a weight loss intervention.
Changes in fatty liver index after consuming a Mediterranean diet: 6-year follow-up of the PREDIMED-Malaga trial.
OBJECTIVE: To analyze the effect of an intervention with a Mediterranean diet supplemented with either extra virgin olive oil or nuts, on the fatty liver index (FLI), compared to a low-fat control diet. METHODS: Participants of the PREDIMED-Malaga trial, free from cardiovascular disease at baseline, but with a high risk to develop it, were included in this study. Anthropometric measurements were assessed and blood samples were taken to calculate participants' FLI at study baseline and after one, 3, 5 and 6 years. Mixed linear models were used to explore the fixed effects of the 3 intervention groups on the FLI as well as their interaction with time. RESULTS: A total of 276 participants were included in the study. Average participant age was 67 years, with 66% of participants being women. The baseline prevalence of NAFL was 57%. The change in the FLI of the control group increased significantly over time (1.13±0.41; P=.006). In the MedDiet+EVOO group, the time trend of the change in the FLI was similar to that of the control group, although it was seen to be lower (-3.90±1.9; P=.038). In the MedDiet+Nuts group, the trend was significantly lower than that of the control group (-1.63±0.62; P=.009). In the MedDiet+Nuts group, the trend of changes in participants' BMI was 0.100 points lower per year compared to the control group (P=.004). In the control group, the change in waist circumference increased significantly over time (0.61±0.16cm/year; P<.001) in contrast to the MedDiet+EVOO group, in which this variable remained stable (-0.51±0.22; P=.019). CONCLUSIONS: A dietary intervention consisting of a Mediterranean diet could delay or slow down the natural progression of NAFL, thus, being beneficial for its prevention and treatment. However, further studies supporting these conclusions have yet to be carried out.
Chemical Composition and Antioxidant Properties of Powders Obtained from Different Plum Juice Formulations.
Among popular crops, plum (Prunus domestica L.) has received special attention due to its health-promoting properties. The seasonality of this fruit makes it impossible to consume it throughout the year, so new products in a powder form may offer an alternative to fresh consumption and may be used as high-quality natural food ingredients. A 100% plum (cultivar "Valor") juice was mixed with three different concentrations of maltodextrin or subjected to sugars removal by amberlite-XAD column, and dried using the freeze, spray, and vacuum (40, 60, and 80 °C) drying techniques. The identification and quantification of phenolic acids, flavonols, and anthocyanins in plum powders was performed by LC-MS QTof and UPLC-PDA, respectively. l-ascorbic acid, hydroxymethylfurfural, and antioxidant capacity were measured by the Trolox equivalent antioxidant capacity (TEAC) ABTS and ferric reducing antioxidant potential (FRAP) methods in order to compare the influence of the drying methods on product quality. The results indicated that the profile of polyphenolic compounds in the plum juice powders significantly differed from the whole plum powders. The drying of a sugar free plum extract resulted in higher content of polyphenolic compounds, l-ascorbic acid and antioxidant capacity, but lower content of hydroxymethylfurfural, regardless of drying method applied. Thus, the formulation of plum juice before drying and the drying method should be carefully selected in order to obtain high-quality powders.