Addition of garlic or onion before irradiation on lipid oxidation, volatiles and sensory characteristics of cooked ground beef

Addition of 0.5% onion was effective in reducing lipid oxidation in irradiated cooked ground beef after 7 day storage. Addition of garlic or onion greatly increased the amounts of sulfur volatiles from cooked ground beef. Irradiation and storage both changed the amounts and compositions of sulfur compounds in both garlic- and onion-added cooked ground beef significantly. Although, addition of garlic and onion produced large amounts of sulfur compounds, the intensity of irradiation odor and irradiation flavor in irradiated cooked ground beef was similar to that of the nonirradiated control. Addition of garlic (0.1%) or onion (0.5%) to ground beef produced a garlic/onion aroma and flavor after cooking, and the intensity was stronger with 0.1% garlic than 0.5% onion treatment. Considering the sensory results and the amounts of sulfur compounds produced in cooked ground beef with added garlic or onion, 0.5% of onion or less than 0.1% of garlic is recommended to mask or change irradiation off-odor and off-flavor.     

Effect of garlic, onion, and their combination on the quality and sensory characteristics of irradiated raw ground beef

Irradiated raw ground beef had lower a*- and b*-values than nonirradiated ones regardless of garlic or onion treatment at 0 d. Irradiation increased TBARS values of control ground beef, but addition of 0.5% onion or 0.1% garlic+0.5% onion reduced oxidative changes during storage. Addition of garlic or onion greatly increased the amounts of sulfur compounds, but the increase was greater with garlic. With irradiation, the profiles and amounts of S-volatiles in raw ground beef changed significantly. However, the intensity of irradiation aroma in irradiated raw ground beef with garlic or onion was similar to that of the nonirradiated control. This indicated that some of the sulfur compounds unique to garlic or onion interacted with common sulfur compounds detected in irradiated meat and masked or changed the odor characteristics of irradiated raw ground beef. It was concluded that >0.5% onion or <0.01% garlic would be needed to mask or prevent irradiation aroma in irradiated raw ground beef.     

Carvacrol, cinnamaldehyde, oregano oil, and thymol inhibit Clostridium perfringens spore germination and outgrowth in ground turkey during chilling

Inhibition of Clostridium perfringens by plant-derived carvacrol, cinnamaldehyde, thymol, and oregano oil was evaluated during abusive chilling of cooked ground turkey. Test substances were mixed into thawed turkey product at concentrations of 0.1, 0.5, 1.0, or 2.0% (wt/wt) along with a heat-activated three-strain C. perfringens spore cocktail to obtain final spore concentrations of ca. 2.2 to 2.8 log CFU spores per g of turkey meat. Aliquots (5 g) of the ground turkey mixtures were vacuum packaged and then cooked in a water bath, where the temperature was raised to 60 degrees C in I h. The products were cooled from 54.4 to 7.2 degrees C in 12, 15, 18, or 21 h, resulting in 2.9-, 5.5-, 4.9-, and 4.2-log CFU/g increases, respectively, in C. perfringens populations in samples without antimicrobials. Incorporation of test compounds (0.1 to 0.5%) into the turkey completely inhibited C. perfringens spore germination and outgrowth (P < or = 0.05) during exponential cooling in 12 h. Longer chilling times (15, 18, and 21 h) required greater concentrations (0.5 to 2.0%) to inhibit spore germination and outgrowth. Cinnamaldehyde was significantly (P < 0.05) more effective (<1.0-log CFU/g growth) than the other compounds at a lower concentration (0.5%) at the most abusive chilling rate evaluated (21 h). These findings establish the value of the plant-derived antimicrobials for inhibiting C. perfringens in commercial ground turkey products.     

Improved quantitative recovery of Listeria monocytogenes from stainless steel surfaces using a one-ply composite tissue

Four sampling devices, a sterile environmental sponge (ES), a sterile cotton-tipped swab (CS), a sterile calcium alginate fiber-tipped swab (CAS), and a one-ply composite tissue (CT), were evaluated for quantitative recovery of Listeria monocytogenes from a food-grade stainless steel surface. Sterile 304-grade stainless steel plates (6 by 6 cm) were inoculated with approximately 106 CFU/cm2 L. monocytogenes strain Scott A and dried for 1 h. The ES and CT sampling devices were rehydrated in phosphate buffer solution. After plate swabbing, ES and CT were placed in 40 ml of phosphate buffer solution, stomached for 1 min and hand massaged for 30 s. Each CS and CAS device was rehydrated in 0.1% peptone before swabbing. After swabbing, CS and CAS were vortexed in 0.1% peptone for 1 min. Samples were spiral plated on modified Oxford agar with modified Oxford agar Rodac Contact plates used to recover any remaining cells from the stainless steel surface. Potential inhibition from CT was examined in both phosphate buffer solution and in a modified disc-diffusion assay. Recovery was 2.70, 1.34, and 0.62 log greater using CT compared with ES, CS, and CAS, respectively, with these differences statistically significant (P < 0.001) for ES and CT and for CAS, CS, and CT (P < 0.05). Rodac plates were typically overgrown following ES, positive after CS and CAS, and negative after CT sampling. CT was noninhibitory in both phosphate buffer solution and the modified disc-diffusion assay. Using scanning electron microscopy, Listeria cells were observed on stainless steel plates sampled with each sampling device except CT. The CT device, which is inexpensive and easy to use, represents a major improvement over other methods in quantifying L. monocytogenes on stainless steel surfaces and is likely applicable to enrichment of environmental samples.     

The Comparison of the Contents of Sugar,Amadori, and Heyns Compounds in Fresh and Black Garlic

Black garlic is produced through thermal processing and is used as a healthy food throughout the world. Compared with fresh garlic, there are obvious changes in the color, taste, and biological functions of black garlic. To analyze and explain these changes, the contents of water‐soluble sugars, fructan, and the key intermediate compounds (Heyns and Amadori) of the Maillard reaction in fresh raw garlic and black garlic were investigated, which were important to control and to evaluate the quality of black garlic. The results showed that the fructan contents in the black garlics were decreased by more than 84.6% compared with the fresh raw garlics, which translated into changes in the fructose and glucose contents. The water‐soluble sugar content was drastically increased by values ranging from 187.79% to 790.96%. Therefore, the taste of the black garlic became very sweet. The sucrose content in black garlic was almost equivalent to fresh garlic. The Amadori and Heyns compounds were analyzed by HPLC‐MS/MS in multiple reaction monitoring mode using the different characteristic fragment ions of Heyns and Amadori compounds. The total content of the 3 main Amadori and 3 Heyns compounds in black garlic ranged from 762.53 to 280.56 μg/g, which was 40 to 100‐fold higher than the values in fresh raw garlic. This result was significant proof that the Maillard reaction in black garlic mainly utilized fructose and glucose, with some amino acids.     

加热方式对大蒜挥发性物质的影响

为探究加热方式对大蒜在色差、气味维度上的变化,实验采用色差仪、电子鼻、气质联用仪分析未加热大蒜(A)、炒制大蒜(B)和蒸制大蒜(C),结合主成分、维恩图等方法分析其差异.色差仪分析表明样品B颜色深,饱和度高,样品A、C颜色浅,饱和度低.电子鼻主成分分析显示样品B、C在风味轮廓上更为相似,与样品A差异大.GC-MS分析显...     

Control of Clostridium perfringens in cooked ground beef by carvacrol, cinnamaldehyde, thymol, or oregano oil during chilling

Inhibition of Clostridium perfringens spore germination and outgrowth by carvacrol, cinnamaldehyde, thymol, and oregano oil was evaluated during abusive chilling of cooked ground beef (75% lean) obtained from a local grocery store. Test substances were mixed into thawed ground beef at concentrations of 0.1, 0.5, 1.0, or 2.0% (wt/wt) along with a heat-activated three-strain C. perfringens spore cocktail to obtain final spore concentrations of ca. 2.8 log spores per g. Aliquots (5 g) of the ground beef mixtures were vacuum-packaged and then cooked in a water bath, the temperature of which was raised to 60 degrees C in 1 h. The products were cooled from 54.4 to 7.2 degrees C in 12, 15, 18, or 21 h, resulting in 3.18, 4.64, 4.76, and 5.04 log CFU/ g increases, respectively, in C. perfringens populations. Incorporation of test compounds (> or = 0.1%) into the beef completely inhibited C. perfringens spore germination and outgrowth (P < or = 0.05) during exponential cooling of the cooked beef in 12 h. Longer chilling times (15, 18, and 21 h) required greater concentrations to inhibit spore germination and outgrowth. Cinnamaldehyde was significantly (P < 0.05) more effective (< 1.0 log CFU/g growth) at a lower concentration (0.5%) at the most abusive chilling rate evaluated (21 h) than the other compounds. Incorporation of lower levels of these test compounds with other antimicrobials used in meat product formulations may reduce the potential risk of C. perfringens germination and outgrowth during abusive cooling regimes.     

Quantification of Spice Mixture Compositions by Electronic Nose: Part I. Experimental Design and Data Analysis Using Neural Networks

ABSTRACT: A quantitative procedure was developed to predict the composition of ternary ground spice mixtures using an electronic nose. Basil, cinnamon, and garlic were mixed in different compositions and presented to an e-nose. Nineteen training mixtures were used to build predictive models. Model performance was tested using 5 other mixtures. Three neural network structures—multilayer perceptron (MLP), MLP using principal component analysis as a preprocessor (PCA-MLP), and the time-delay neural network (TDNN)—were used for predictive model building. All 3 neural network models predicted the testing mixtures' compositions with a mean square error (MSE) equal or less than 0.0051 (in a fraction domain where sum of fractions = 1). The TDNN provided the smallest MSE.     

Inhibition of heterocyclic aromatic amine formation in fried ground beef patties by garlic and selected garlic-related sulfur compounds

The effects of garlic and selected organosulfur compounds (diallyl disulfide, dipropyl disulfide, diallyl sulfide, allyl methyl sulfide, allyl mercaptan, cysteine, and cystine) on the formation of heterocyclic aromatic amines (HAAs) in fried ground beef patties were evaluated. Minced garlic cloves (ca. 4.8 to 16.7%, wt/wt) or organosulfur compounds (0.67 mmol) were added directly to ground beef. Patties (100 g) were fried at 225 degrees C (surface temperature) for 10 min per side. Two patties were fried for each replication, and five replicates were analyzed for each treatment. For each replicate, four subsamples were analyzed (two unspiked subsamples for concentration and two spiked subsamples for the recovery of HAA standards). The volatile sulfur compounds significantly (P < 0.05) reduced concentrations of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine by reductions of 46 to 81%, while average reductions of 35, 22, and 71%, were achieved with cystine, cysteine, and whole garlic, respectively. The volatile sulfur compounds reduced concentrations of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline by 34 to 67%, while reductions of 25, 19, and 63% (P < 0.05) were achieved with cystine, cysteine, and whole garlic, respectively. These studies confirm that garlic and some organosulfur compounds have the potential to reduce HAA formation incooked beef patties.     

Lipid and cholesterol oxidation in chicken meat are inhibited by sage but not by garlic

The effects of the addition of sage and garlic in chicken meat on lipid and cholesterol oxidation, having as prooxidant factors the addition of salt, thermal treatment, and frozen storage, were evaluated. The content of unsaturated fatty acids did not change in the presence of sage; on the contrary, with garlic, the content of these fatty acids decreased after cooking and storage. Hexanal and pentanal contents were lower in patties containing sage, and higher in those with garlic. The 7-ketocholesterol was the cholesterol oxide found in higher amount in raw chicken on day 0, while the formation of 7β- and 7α-hydroxycholesterol was verified only from day 30 on. Cooking and storage resulted in increase of total cholesterol oxides and decrease of α- and γ-tocopherol. Sage was effective in controlling lipid and cholesterol oxidation, minimizing the prooxidant effects of salt, cooking, and storage. However, garlic presented no effect as antioxidant and accelerated lipid oxidation. PRACTICAL APPLICATION: The addition of sage to chicken meat (0.1 g/100 g) is a good alternative to prevent and delay the formation of compounds derived from lipid oxidation that are responsible for off-flavors and loss of nutritional quality during long-term frozen storage. Care must be taken when using garlic to seasoning chicken meat products, such as hamburgers and meatballs, especially cooked or precooked due to its potential to promote lipid oxidation and consequently raising the risk of having the product rejected by the consumer.     

Thermal Kinetics of Color Change, Rheology, and Storage Characteristics of Garlic Puree/Paste

ABSTRACT Kinetics of color change of garlic puree at selected temperatures and rheological behavior and effects of packaging materials and storage temperatures on color of garlic paste were investigated. Results indicated that color change during thermal processing of garlic puree followed first-order reaction kinetics with an activation energy of 13.78 kJ/mol. Garlic paste behaved as a pseudoplastic material and flow activation energy at 100 rpm equaled 13.30 kJ/mol. Both temperature and duration of storage had effect (P≤ 0.05) on total color of garlic paste. Degreening of garlic paste was observed during storage at 25°C and complete degreening occurred at about 48 to 52 d. Storage of garlic paste at 5°C enhanced greening.     

Deodorization of Garlic Breath by Foods,and the Role of Polyphenol Oxidase and Phenolic Compounds

Garlic causes a strong garlic breath that may persist for almost a day. Therefore, it is important to study deodorization techniques for garlic breath. The volatiles responsible for garlic breath include diallyl disulfide, allyl mercaptan, allyl methyl disulfide, and allyl methyl sulfide. After eating garlic, water (control), raw, juiced or heated apple, raw or heated lettuce, raw or juiced mint leaves, or green tea were consumed immediately. The levels of the garlic volatiles on the breath were analyzed from 1 to 60 min by selected ion flow tube mass spectrometry (SIFT‐MS). Garlic was also blended with water (control), polyphenol oxidase (PPO), rosemarinic acid, quercetin or catechin, and the volatiles in the headspace analyzed from 3 to 40 min by SIFT‐MS. Raw apple, raw lettuce, and mint leaves significantly decreased all of the garlic breath volatiles in vivo. The proposed mechanism is enzymatic deodorization where volatiles react with phenolic compounds. Apple juice and mint juice also had a deodorizing effect on most of the garlic volatiles but were generally not as effective as the raw food, probably because the juice had enzymatic activity but the phenolic compounds had already polymerized. Both heated apple and heated lettuce produced a significant reduction of diallyl disulfide and allyl mercaptan. The presence of phenolic compounds that react with the volatile compounds even in the absence of enzymes is the most likely mechanism. Green tea had no deodorizing effect on the garlic volatile compounds. Rosmarinic acid, catechin, quercetin, and PPO significantly decreased all garlic breath volatiles in vitro. Rosmarinic acid was the most effective at deodorization.     

Fate of surfactants in membrane bioreactors and conventional activated sludge plants

Two membrane bioreactors (MBRs) were operated at high sludge retention time (SRT) (between 30 and 75 d) in parallel to a conventional activated sludge plant (CASP) conducted at SRT = 10 d. The fate of linear alkylbenzene sulfonate (LAS), nonylphenol ethoxylates (NP(n)EO, n = 1-15), nonylphenoxy carboxylates (NP(n)EC, n = 1-2), and nonylphenol (NP) in these systems was investigated. All systems were very efficient in the removal of LAS (around 99%). The analysis of variance showed that the difference in the removal efficiency of LAS in the CASP and the MBR operated at SRT = 65-75 d (respectively 99.0 ± 0.43 and 99.8 ± 0.11) were significant (p < 0.05), confirming the importance of SRT in the removal of LAS. Comparison between the CASP and the MBRs in the removal efficiency of nonylphenolic compounds were conducted considering NP(3-15)EO, the sum of NP(1-15)EO, NP(1-2)EC, and nonylphenol (NP). In all cases MBRs were more efficient than the CASP. In the case of NP the removal was about 76 ± 7.5% for the CASP and 90% ± 12.1 and 82 ± 8.7% for the MBRs. Better performance of MBRs in the removal of nonylphenolic compounds can be attributed to a better degradation. For example, if the sum of NP(1-15)EO and NP(1-2)EC is considered, estimated biodegradation was about 48% for the CASP and 72% for MBRs.     

Moisture Sorption Studies on Garlic Powder

The moisture sorption isotherms of two samples of garlic powder, one containing corn starch (CS) and the other without starch, were deter-mined using saturated salt solutions. Monolayer values were calculated from the isotherms using the Brunauer, Emmett and Teller (BET) equation. The addition of CS at 5% slightly increased the monolayer value of the garlic powder, but it had little effect on the caking behavior of the powder. Equilibrium relative humidity (ERH) of garlic powder corresponding to the monolayer value was found to be 14%.     

Cure Levels, Processing Methods and Meat Source Effects on Low-fat Frankfurters

Frankfurters were manufactured from lean meats (100% beef and 50:50 beef-pork) to contain reduced levels of fat (about 1.3%). A curing solutibn was added to yield 160% of fresh meat weight. Three processing methods, coarse ground tumbled, fine ground tumbled and fine ground emulsified were used. All products were cooked in live steam to 71°C internal temperature. Product yields, penetrometer values, color, chemical composition, caloric content and added water were evaluated. Emulsified frankfurters from 50:50 beef-pork mixtures at 160% cure had texture similar to conventional product as well as increased (P<0.05) yields, acceptable color and 74% fewer calories.     

Effect of cold atmospheric plasma and pulsed electromagnetic fields on strawberry quality and shelf-life

The effect of cold atmospheric plasma (CAP) and pulsed electromagnetic fields (PEMF) on the metabolic process, microbiological, enzymatic and quality parameters of fresh strawberries, after processing and during storage at 1 and 6 °C, was studied. CAP was more effective on microorganisms, reducing the total viable count by ~0.9 logCFU/g. Phenolic compounds and antioxidant activity were increased after CAP processing by ~20.9 and 16.5%, respectively. PEMF strawberries were firmless by ~16% compared to control. Both treatments did not significantly affect the weight loss, color, anthocyanins content and pH-value. B-glucosidase activity was higher for PEMF strawberries by at least 35 and 20%, compared to control and CAP respectively, explaining PEMF enhancing aromatic-profile. Ascorbic acid was decreased during storage, nevertheless, nonthermal treated samples showed higher values by at least 10%, compared to control samples. The shelf-life at 1 °C for control, CAP and PEMF strawberries was estimated as 13, 17 and 15 days, respectively.     

Bio-preservation of fresh-cut tomatoes using natural antimicrobials

Effects of several natural volatile compounds such as methyl jasmonate (MJ), ethanol (ETOH), their combination (MJ–ETOH), tea tree oil (TTO) and garlic oil (GO) were evaluated on fresh-cut tomato storage at 5 °C for 15 days. Microbial growth, in-packaged atmosphere, quality attributes (firmness and color) and bioactive compounds (lycopene content, ascorbic acid and phenolic compounds) of fresh-cut tomatoes were determined. The shelf-life based on microbial growth was longer on fresh-cut tomatoes treated with natural volatile compounds than in control fresh-cut tomatoes. Treatment with ETOH combined with MJ was more effective in suppressing microbial proliferation than the individual treatments with each natural volatile compound. The lowest in-packaged atmosphere modification was detected in fresh-cut tomatoes treated by ETOH. In addition, this treatment better maintained firmness and color attributes than those treated with the other antimicrobial compounds. Related to the bioactive compounds, the use of MJ let keep higher content of lycopene, ascorbic acid and phenolic compounds than the other treatments. Thus, the shelf-life of fresh-cut tomatoes could be prolonged by the use of natural antimicrobials, which do not have significant negative effects on health-related compounds.     

The effect of paprika, garlic and salt on rancidity in dry sausages

Eight batches of ground fat and eight batches of a mixture of meat and fat (70 and 30%, respectively), were prepared by adding salt, paprika and garlic, in the proportions used for making chorizo - a dry fermented sausage - stuffed into natural casings and then ripened. The evolution of rancidity in these products was evaluated by means of total free fatty acid content, peroxide value and TBARS during the ripening period. Spanish paprika and salt showed antioxidant and prooxidant properties, respectively. Paprika was even able to inhibit the prooxidant effect of salt. Also, four batches of chorizo were made to compare the antioxidant effect of the spices (garlic and paprika) with a mixture of nitrate, nitrite and ascorbic acid. In this respect, paprika and garlic were as effective as the mixture of additives in inhibiting lipid oxidation.     

A meta-analysis of randomized, double-blind, placebo-controlled trials for the effects of garlic on serum lipid profiles

BACKGROUND: Inconsistent results were obtained for the lipid‐regulating effects of garlic in clinical trials. With increasing interest in complementary medicine for hyperlipoidemia, it is important to explore the real effects of garlic. This meta‐ analysis was performed to investigate the influence of garlic on serum lipid parameters. RESULTS: A total of 26 studies were included into meta‐analysis. Overall, garlic was superior to placebo in reducing serum total cholesterol (TC) and triglyceride (TG) levels. Compared with the placebo groups, serum TC and TG levels in the garlic group were reduced by 0.28 (95% CI, ? 0.45, ? 0.11) mmol L^?1 (P = 0.001) and 0.13 (95% CI, ? 0.20, ? 0.06) mmol L^?1 (P < 0.001), respectively. The effects of garlic were more striking in subjects with long‐term intervention and higher baseline TC levels. Garlic powder and aged garlic extract were more effective in reducing serum TC levels, while garlic oil was more effective in lowering serum TG levels. In contrast, garlic did not influence other lipid parameters, including low‐density lipoprotein cholesterol, high‐density lipoprotein cholesterol (HDL‐C), apolipoprotein B, and TC/HDL‐C ratio. CONCLUSION: Garlic could reduce serum TC and TG levels, and garlic therapy should benefit patients with risk of cardiovascular diseases. Copyright © 2012 Society of Chemical Industry     

Calcium chloride and tricalcium phosphate effects on the pink color defect in cooked ground and intact turkey breast

Calcium chloride (250, 500 ppm) was examined for its ability to reduce the pink color defect induced by sodium nitrite (10 ppm) and nicotinamide (1.0%) in cooked ground turkey in the presence and absence of sodium tripolyphosphate (0.25, 0.5%) and sodium citrate (0.5, 1.0%). The ability of tricalcium phosphate (0.1–0.5%) to reduce pink cooked color also was evaluated in ground turkey and both calcium chloride and tricalcium phosphate were tested for their effects on pink cooked color in whole breast muscle. The combination of calcium chloride and sodium tripolyphosphate, not calcium chloride alone, was necessary for a reduction in pink cooked color induced by nicotinamide. Subsequently, in the presence of phosphate, both calcium chloride and sodium citrate reduced pink cooked color and were most effective in combination. Tricalcium phosphate also was capable of reducing pink cooked color in ground turkey, however substituting tricalcium phosphate for sodium tripolyphosphate resulted in lower pH and cooking yields. Neither calcium chloride nor tricalcium phosphate was capable of reducing pink cooked color in whole turkey breast. Currently, a combination of sodium tripolyphosphate, calcium chloride, and sodium citrate represents the most suitable means for reducing or preventing the pink color defect in uncured ground turkey.