The effect of instant tea on the aroma of duck meat.

Tea products, such as instant tea, have been shown to improve the aroma of meat products. However, the mechanisms by which tea products enhance meat aroma have not been adequately explained. In this study, we analyzed the impact of instant tea on the aroma of duck meat. Our results showed that treatment with instant tea led to increases in floral, baked, and grassy notes while reducing fishy and fatty notes. Several alcohols, aldehydes, ketones, indole and dihydroactinidiolide exhibited significantly increased OAVs. Conversely, certain saturated aldehydes, unsaturated aldehydes and alcohols displayed significantly decreased OAVs. The enhanced floral, baked and grassy notes were attributed to volatile compounds present in instant tea. The reduction in fishy and fatty notes was linked to polyphenols in instant tea interacting with nonanal, undecanal, (E)-2-octenal, (E)-2-nonenal, (E)-2-decenal, and 2,4-decadienal through hydrophobic interactions and electronic effects. This study enhances our understanding of how tea products improve meat aromas.

Condiment Recipes Lead to Reduced Generation of Carcinogenic Polycyclic Aromatic Hydrocarbons in Duck Variety Meat During Charcoal Grilling.

The current study aimed to evaluate the impact of charcoal grilling in the generation of various polycyclic aromatic hydrocarbons in the tissues of 5 different organs (leg, chest, wings, liver, and heart) of falcated ducks (Mareca falcata) before and after pasting them with different condiment recipes (R1, R2, R3, and R4). All condiment-pasted and control samples before/after charcoal grilling were pursued in RP-HPLC for quantification of unknown PAHs. Tissues from grilled raw leg meat of the control sample showed significantly higher (P ≤ .05) concentration (42.40 ng/g) of overall PAHs as compared to all other grilled samples. However, overall PAHs concentration (9.99 ng/g) in charcoal grilled tissues of leg meat pasted with R4 condiment recipe was decreased 76.43% significantly (P ≤ .05) as compared to all other recipes of pasted charcoal grilled samples. All PAHs, particularly naphthalene, fluorene, phenanthrene, and acenaphthalene were decreased significantly (P ≤ .05) to none detectable level in all tissue samples when grilled after treating with R4 condiment recipe. All condiment recipes reduced total PAHs level below MRL's set by the international guidelines. Recipe R4, a rich source of antioxidants, significantly neutralized and reduced the generation of PAHs in duck leg meat tissue sample during wood charcoal grilling.

Influence of E-beam irradiation on microbiological and physicochemical properties and fatty acid profile of frozen duck meat.

This study investigated the effect of different doses (0, 3, and 7 kGy) of e-beam on the microbiological and physicochemical qualities and the profile of fatty acids of the frozen duck meat (FDM). Electron beam at the dose of 3 kGy showed more than 2 log and 1 log cycles of reduction in the total bacterial (TAB) and coliform counts (TCC), respectively. The results indicated an increase in the TBARS values (1.50 ± 0.02 mg MDA/kg), peroxide value (0.83 ± 0.04 meq peroxide/kg), and total volatile base nitrogen (1.31 ± 0.16 mg/100 ml), but no effect on the sensory parameters. Irradiation lowered the lightness (L*) (31.87 ± 0.98) and redness (a*) (11.04 ± 0.20) values but elevated the metmyoglobin content in FDM. In addition, irradiation had no effect on the benzopyrene content; however, a reduction was observed in the vitamin A (0.239 ± 0.015 µg/g) and vitamin E (1.847 ± 0.075 µg/g) contents of the FDM samples. There were no trans-fatty acids present in the treated (irradiated) as well as the untreated (nonirradiated) meat samples (FDM), whereas the fatty acid content decreased in irradiated samples, in contrast with the nonirradiated control. Electronic nose clearly discriminated between the nonirradiated and irradiated FDM based on principal component analysis. It is concluded that the e-beam successfully improved the microbial quality of FDM with slight changes in physicochemical properties, but without altering its sensory properties.

Carcinogenic and non-carcinogenic risk assessment of heavy metals contamination in duck eggs and meat as a warning scenario in Thailand.

The aim of this study was to determine the levels of Pb, Cd, Co and Cr in duck eggs and duck meat and to assess the risk of carcinogenic and non-carcinogenic effects caused by the consumption of duck products collected in Thailand. The human health risk assessment refers to the formulation of the USEPA standard focused on Estimated Daily Intake (EDI), Incremental Lifetime Cancer Risk (ILCR), Target Hazard Quotient (THQ) and Total Target Hazard Quotient (TTHQ). Ninety-eight percent of duck egg samples in this study were contaminated with Pb, with the average level typically above the standard limit. The EDI evaluation of heavy metal in children was the highest for all metals in the eggs. The calculated ILCR levels of Pb, Cd and Cr in eggs and meat consumption were higher than 10-4 in children, adults, males, and females. Children were at risk when consuming contaminated duck eggs and the risk was higher than in adults by 3.9 times for Pb, Cd and Cr. This finding suggests that there is a high probability of cancer risk, particularly for children, which is higher than adults by absorption of these carcinogenic heavy metals through eggs. The calculation of THQ if consuming heavy metals contaminated duck eggs and meat in human exposure (70years) could conclude that the THQ male was higher than the female for all metals. However, the calculations of TTHQ for Pb, Cd, Co and Cr contamination in a duck egg and meat scenario for adults, males and females were still below the standard limit of 1, which means there was no risk, although there could be adverse health effects. This study suggested that children should be the focus of long-term monitoring for evaluating the carcinogenicity of these metals, more specifically in males.

Assessment of microbial contaminations in commercial frozen duck meats and the application of electron beam irradiation to improve their hygienic quality.

BACKGROUND: High microbial load is a serious concern in terms of the health-related safety of products of animal origin. In this study, the microbial loads of commercial frozen duck-meat products, including bone-in whole raw, boneless sliced raw, and boneless whole smoked, were investigated for pathogenic contamination. The application of electron beam irradiation was also investigated. RESULTS: The samples revealed a serious microbial threat (102 -105 CFU g-1 for total aerobic bacteria and positive for foodborne pathogens), which required effective decontamination technology. Electron-beam irradiation (0, 1, 3, and 7 kGy) could potentially improve the hygienic quality of duck-meat samples. The D10 values for Listeria monocytogenes and Salmonella Typhi were 0.47 and 0.51 kGy, respectively. A direct epifluorescent filter technique and aerobic plate count (DEFT/APC) method was used for screening, while electron-spin resonance (ESR) spectroscopy and gas chromatography with mass spectrometry were effective as confirmatory techniques to identify radiation-induced markers in frozen duck meat. CONCLUSION: Electron-beam irradiation has the potential to ensure the microbial safety and hygienic quality of commercial duck meats. Identification of the samples for their irradiation history was also possible using radiation-induced detection markers, including the DEFT/APC, hydroxyapatite ESR radicals, and hydrocarbons. © 2018 Society of Chemical Industry.

Control of Listeria innocua Biofilms on Food Contact Surfaces with Slightly Acidic Electrolyzed Water and the Risk of Biofilm Cells Transfer to Duck Meat.

Biofilm formation on food contact surfaces is a potential hazard leading to cross-contamination during food processing. We investigated Listeria innocua biofilm formation on various food contact surfaces and compared the washing effect of slightly acidic electrolyzed water (SAEW) at 30, 50, 70, and 120 ppm with that of 200 ppm of sodium hypochlorite (NaClO) on biofilm cells. The risk of L. innocua biofilm transfer and growth on food at retail markets was also investigated. The viability of biofilms that formed on food contact surfaces and then transferred cells to duck meat was confirmed by fluorescence microscopy. L. innocua biofilm formation was greatest on rubber, followed by polypropylene, glass, and stainless steel. Regardless of sanitizer type, washing removed biofilms from polypropylene and stainless steel better than from rubber and glass. Among the various SAEW concentrations, washing with 70 ppm of SAEW for 5 min significantly reduced L. innocua biofilms on food contact surfaces during food processing. Efficiency of transfer of L. innocua biofilm cells was the highest on polypropylene and lowest on stainless steel. The transferred biofilm cells grew to the maximum population density, and the lag time of transferred biofilm cells was longer than that of planktonic cells. The biofilm cells that transferred to duck meat coexisted with live, injured, and dead cells, which indicates that effective washing is essential to remove biofilm on food contact surfaces during food processing to reduce the risk of foodborne disease outbreaks.

Generation of bioactive peptides from duck meat during post-mortem aging.

The objective of this study was to investigate the endogenous release of bioactive peptides in duck meat during 7days of post-mortem aging. The degradation of muscle proteins led to release of small peptides (<5kDa). The peptides formed in the samples after 3days post-mortem exhibited highest DPPH radical scavenging, oxygen radical scavenging (ORAC) and ferric reducing antioxidant power (FRAP). By using size-exclusion chromatography, the initial extract was purified into three fractions (A-C) in which fraction C exhibited the highest antioxidant activity. In total 18 peptides were sequenced and identified in the fractions by nano LC-MS/MS. Among these peptides, the peptides of fraction C possessed the lowest molecular weight and consisted of the highest amount of hydrophobic amino acid, which might be responsible for the antioxidant property of aged duck meat. The present findings provide an insight into the release of bioactive peptides in duck meat during post-mortem aging.

Assessment of Microbial and Radioactive Contaminations in Korean Cold Duck Meats and Electron-Beam Application for Quality Improvement.

Animal-origin food products pose serious threat to public food safety due to high microbial loads. The microbial and radioactive contaminations in commercial cold duck meat products were evaluated. Ten different lots of commercial samples (C1-C10) were classified based on type and smoking process. All samples were highly contaminated (< 4-7 Log CFU/g) with total aerobic bacteria (TAB), yeasts and molds (Y&M), and 7 samples (C1-C7) were positive for coliforms. Furthermore, three samples were contaminated with Listeria monocytogenes (C4-C6) and one with Salmonella typhimurium (C6). No radionuclides (131I, 137Cs, and 134Cs) were detected in any sample. The results of DEFT (direct epifluorescent filter technique)/APC (aerobic plate count), employed to screen pre-pasteurization treatments of products, indicated that smoked samples were positive showing DEFT/APC ratios higher than 4. Notably, the samples showed a serious threat to microbial safety, thus were irradiated with electron-beam (e-beam). The D10 values for S. typhimurium and L. monocytogenes were 0.65 and 0.42 kGy, respectively. E-beam application at 3 and 7 kGy resulted in reduction of initial TAB, Y&M, and coliform populations by 3 and 6 log cycles, respectively. Thus, e-beam was proven to be a good decontamination approach to improve the hygiene of cold duck meat.

Identification and characterization of antioxidant peptides from enzymatic hydrolysates of duck meat.

The objective of this study was to prepare antioxidant peptides from duck meat hydrolysate (DMH) using Protamex. The DPPH(•) scavenging activity, hydroxyl radical ((•)OH) scavenging activity, and Fe(2+)-chelating ability of DMH were investigated. DMH was separated into three groups, MWCO-1 (69.57%), MWCO-2 (9.53%), and MWCO-3 (8.21%), by ultrafiltration. MWCO-3 exhibited the highest DPPH(•) scavenging activity (83.17 ± 0.73%) and was subsequently fractionated by using gel filtration chromatography to obtain fraction B (40.90%). Fraction B5 (6.71%) obtained from ion exchange chromatography exhibited the highest DPPH(•) scavenging activity (93.63 ± 0.13%) and contained seven peptides which were characterized by LC-MS/MS. Among these peptides, LQAEVEELRAALE showed the highest DPPH(•) scavenging activity (93.36 ± 0.53%) and Fe(2+)-chelating ability (87.13 ± 0.47%) and IEDPFDQDDWGAWKK exhibited the highest (•)OH scavenging activity (46.51 ± 0.16%). The results presented here indicated that DMH could serve as a suitable source of antioxidant peptides.

Effect of duck meat consumption on thyroid hormone concentrations and energy metabolism of Sprague-Dawley rats.

The two diets, a duck meat diet (DMD) and a control casein diet (CD) were isocaloric (15.9 kJ/g dry matters), and contained 18.3% protein, 7.4% fat, 60.0% carbohydrate. The selenium contents in casein, duck meat powder, CD and DMD were 0.061, 0.549, 0.123 and 0.225 mg/kg. Rats in the DMD group had higher serum selenium concentrations (p<0.05) and liver 5'-deiodinase activities (p<0.05). As a result, duck meat consumption increased serum tri-iodothryonine (T3) concentrations (p<0.05) and decreased serum thyroxine (T4) concentrations (p<0.05). The lower serum T4 concentrations (p<0.05) were also supported by the lower total content of tyrosine and phenylalanine in duck meat powder compared to casein (7.72 vs 10.13). Compared to casein, duck meat powder had higher total content of glutamic acid, leucine, aspartic acid, serine, and alanine (44.68 vs 49.21), which led to higher serum TBG concentrations (p<0.05) in the DMD group. Hence, the DMD group had lower serum free T4 (FT4) concentrations (p<0.05), and lower serum free T3 (FT3) concentrations on day 14 (p<0.05), which significantly decreased the energy expenditure of rats in the DMD group, with lower liver Na,K-ATPase and Ca-ATPase activities (p<0.05), lower OCRs and rectal temperature, especially on day 13 (p<0.05), higher body weight (p<0.05), and body-weight gain (p<0.05). We concluded that duck meat consumption decreased the energy metabolism of rats by multiple-step regulation of THs.