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Flavor Profiles of Vacuum Packaged and Polyvinyl Chloride Packaged Ground Beef: A Comparison of Cooked Flavor Changes Occurring during Product Display
Journal of Food Science
Abstract
Vacuum packaged (VP) ground beef was compared to polyvinyl chloride (PVC) packaged product by describing and quantifying via flavor profiling those flavor changes occurring during display. VP samples displayed for 24 days had a more constant profile than did PVC samples displayed for 5 days. The initial beefy, fresh impact of VP samples declined only slightly during display. The beefy note became briefer and was replaced by a lingering sourness. Bloody/serumy notes changed to metallic/sharp notes. After 3-day display, PVC samples were bland with a threshold amount of stale note. At 5-day display, beef identity and freshness of the PVC sample were very low. Bloody/serumy was not detected and blandness was replaced by a lingering stale note.
... It is obvious from the present study that with such non-specific terms, sensory subtleties in developed WOF could not have been fully described. Not until the studies ofJohnson and Civille (1986)and Lynch, Kastner,Cavl and Kropf (1986)in beef andLyon (1987)in chicken, were attempts were made to develop detailed descriptive vocabularies for characterising WOF in cooked meats. Sensory vocabularies such as these demonstrated that the lipid oxidation aspects of WOF could only be described in detail by the combination of a number of specific descriptors from a sensory perspective. ...
Two independent sensory profiles were carried out to evaluate warmed-over flavour (WOF) development in cooked, chill-stored and reheated pork patties. The patties were derived from the Musculus semimembranosus of animals subjected to different pre-slaughter stress treatments. All patties were stored in oxygen permeable bags at 4°C for 0, 1, 2, 3 and 5 days to facilitate WOF development. In addition, thiobarbituric acid reactive substances (TBARS), conjugated dienes, pH, water content, total lipids and the fatty acid compositions of phosphatidyl choline (PC), phosphatidyl ethanolamine (PE) and total lipids, were measured in the cooked meat patties. A data analytical strategy involving Analysis of Variance-Partial Least Squares Regression (ANOVA-PLSR), to determine relationships between the design variables (WOF and pre-slaughter stress) and the sensory-chemical data, and PLSR to elucidate predictive links between the sensory and chemical data was utilised. WOF was found to involve the development of lipid oxidation derived nuance off-flavour and odour notes, e.g. rancid-like flavour and linseed oil-like odour, in association with a concurrent decrease in cooked pork meat-like flavour. The reduction in "meatiness", over the initial days, 0-2 of WOF development was attributed to the degradation of both, unstable sulfur-containing amino acids in meat proteins and sulfur-containing "meaty" aroma compounds. Whereas, at the later days, 3-5 of WOF development the "meaty" loss was ascribed to perceptual masking by lipid oxidation products. TBARS and conjugated dienes were found to be significant (P<0.05) predictors of the sensory terms related to the lipid oxidation aspect of WOF. Whilst the polyunsaturated fatty acid (PUFAs) contents of PE, PC and the total lipids were found to decrease with WOF development, reflecting their loss in lipid oxidation reactions. The sensory variation related to pre-slaughter stress appeared to be distinct from WOF variation and was described by a sour to sweet taste continuum. However, interactions were noted that indicated increasing pre-slaughter stress resulted in a decreased sensory perception of WOF. Moreover, pH and water content were found to significantly (P<0.05) predict the sensory effects resulting from pre-slaughter stress.
IntroductionMaterials And Methods
Results And DiscussionAcknowledgmentsReferences
A lexicon describing the flavor characteristics of beef across different cuts, grades, and cooking temperatures and methods was developed. Four major cuts of the United States Department of Agriculture (USDA) quality grade beef were cooked to five endpoint temperatures using braising, broiling (oven broiling and electric charbroiling), roasting and grilling (indoor and outdoor grilling). Six highly trained panelists identified and defined a total of 38 aroma and flavor characteristics in 176 beef samples. Beef identity, brown/roasted, bloody/serumy, metallic, fat-like, overall sweet, sour aromatics and five tastes were present in practically all samples. Other attributes were present only in certain samples, depending on either the sample group or the cooking method/endpoint temperature combination used. This lexicon potentially offers the beef industry a standard tool to identify and quantify flavor attributes as impacted by temperature, cooking method, aging process, storage time, diet regime, packaging, USDA quality grades, etc.
Until now, the beef industry's main focus has been to assess beef tenderness and juiciness, with an emphasis on ways to improve beef texture. Meat companies and academic institutions have been using the 1995 American Meat Science Association guidelines to assess the flavor of beef, which are not comprehensive. Recent work has focused on flavor, and the industry needs a standardized flavor lexicon that can be used for many projects. It is important for the industry to be able to systematically identify and quantify flavor attributes that drive consumer acceptance.
Twenty crossbred steers with a mean liveweight of 475 kg and grading Canada Al or A2 were utilized in two distinct but related experiments (10 steers per experiment) to evaluate the effects of: (1) lactic acid versus water sprays prior to carcass chilling, and (2) postmortem aging for up to 28 days on the profiles and certain physical properties of bovine longissimus roasts. Results indicated that the spray (lactic acid or water spray) treatments exerted little influence on flavor, moisture loss, and cooking properties. They also demonstrated that extension of postmortem vacuum packaged aging for up to 28 days appeared to impart a slightly beneficial influence on beef longissimus muscle flavor by increasing the intensity of the beefy and fatty character notes (P< 0.05) while not influencing moisture loss or cooking properties (P> 0.05).
Chicken patties (50% light/50% dark meat) were used as training and testing samples by a 10-member panel to develop descriptive terms appropriate for profiling the taste/aroma character notes of fresh and reheated chicken meat. A free word association list of 45 terms was developed in initial training sessions. These terms were used to obtain frequency of use and intensity data for statistical analyses to determine appropriateness of the terms for profiling and discriminating among fresh and reheat treatments of the chicken patties. The initial list was reduced to 31 terms by a frequency-use delimiter of 40% over four replications and by MANOVA probability values (P > .05) for sample differences. FACTOR (principal components) analysis applied to the reduced list of terms indicated six logical associative groupings of terms that explained 77% variation in the data. A final list of 12 descriptors was developed by omitting redundant terms in a factor grouping.
Fresh pork sausage patties containing carrageenan, without or with soy protein and an antioxidant were packaged with or without vacuum. They were evaluated for sensory properties, visual color, thiobarbituric acid reactive substances (TBARS), and Hunter color ‘L’, ‘a’, ‘b’ values at 4-wk intervals during 16 wk frozen storage. Rosemary extract was as effective as butylated hydroxytoluene (BHT)/propyl gallate (PG)/citric acid (CA) in antioxidant properties, but patties with BHT/PG/CA showed less surface discoloration (P < 0.05). In fat-control (FC) products, antioxidants combined with vacuum packaging provided optimum protection against rancidity. With vacuum packaging (VP), reduced-fat products maintained acceptable quality (TBARS and sensory properties) during 16 wks frozen storage.
Volatile compounds of raw beef from Asturiana de los Valles, Morucha, Parda Alpina, Pirenaica, and Retinta cattle breeds were studied. Steaks were packaged under 60% O2, 30% CO2, and 10% N2, and 53 volatile compounds were tentatively identified by purge-and-trap extraction and gas chromatography with mass spectrometry after 0, 5, 10, and 15 d of chill storage. The degradation of beef quality with increasing storage time was evidenced by the increase in 2,3,3-trimethylpentane, 2,2,5-trimethylhexane, 3-octene, 3-methyl-2-heptene, 2-octene, and 2-propanone and by the decrease in dimethyl sulfide. Consequently, some of the volatile compounds, which are believed to be formed by thermal degradation of meat, might be formed during chill storage, and the rate of formation of some was dependent on the specific compound.
Over 1000 flavor compounds in meats have been identified. However, a single compound or group of compounds responsible for “meaty flavor” has not been identified due to the overall complexity of meat flavor. Meat flavor is dependent on the pool of flavor precursors in the meat tissue, the chemical reactions during processing, and subsequent storage. The precise flavor precursors vary between and within species, beef, pork, lamb, and poultry.
Beef-carrageenan (BC; 10% fat) patties—with sodium ascorbate (0.05%), sodium lactate (3%), sodium tripolyphosphate (0.3%), ascorbate-phos-phate, ascorbate-lactate, or none—and 20%-fat all-beef patties were cooked, aerobically or vacuum packaged, and stored at 4°C or −20°C. Fat level had a greater effect on texture than did additives. Lactate and phosphate increased cooking yield of BC patties. Phosphate was antioxidative but not antimicrobial. Ascorbate was antioxidative and reduced aerobic plate counts (APCs) of aerobically packaged refrigerated BC. Lactate reduced APCs of both aerobically and vacuum packaged BC patties. Lactate had a prooxidative effect in aerobically-packaged/frozen patties but showed no such effect in vacuum-packaged/frozen patties or refrigerated patties. Ascorbate-phosphate was most effective in minimizing flavor deterioration in refrigerated BC patties.
Neutral lipid (NL) and phospholipid (PL) fractions and their corresponding fatty acid profiles from the L. dorsi of Bison, Hereford, and Brahman steers of similar age finished on identical diets were determined. Compositional differences were related to sensory characteristics of the samples. Phosphatidylcholine + lysophosphatidylethanolamine (PC + LPE) existed in the highest concentration in all samples evaluated followed by lysophosphatidylcholine (LPC), phosphatidylethanolamine (PE), sphingomyelin (SPH), fraction one and phosphatidylserine (PS). Bison contained more total PL, particularly PC + LPE and LPC, than the other two bovine species. Polyunsaturated fatty acid (PUFA) composition of these PL was greater for Bison. Off-flavor and aftertaste increased with increasing levels of PC + LPE and LPC due to their greater composition of PUFA.
The objectives of this study were to use a meat flavor lexicon to identify and quantify flavor differences among different types of meats such as beef, chicken, lamb, pork, and turkey, and to identify and quantify specific flavor attributes associated with “beef flavor” notes. A trained descriptive panel with 11 participants used a previously developed meat lexicon composed of 18 terms to evaluate the flavor of beef, chicken, pork, turkey, and lamb samples. Results show that beef and lamb samples can be described by flavor attributes such as barny, bitter, gamey, grassy, livery, metallic, and roast beef. Inversely related to these samples were pork and turkey and those attributes that were closely related to them, namely brothy, fatty, salty, sweet, and umami. Chicken was not strongly related to the other types of meats or the attributes used. The descriptive panel also evaluated samples of ground beef mixed with chicken to identify and quantify flavor attributes associated with a “beef flavor.” Meat patties for this portion consisted of ground beef mixed with ground chicken in varying amounts: 0%, 25%, 50%, 75%, and 100% beef, with the remainder made up of chicken. Beef and beef-rich patties (75% beef) were more closely related to flavor attributes such as astringent, bloody, fatty, gamey, metallic, livery, oxidized, grassy, and roast beef, while chicken was more closely associated with brothy, juicy, sour, sweet, and umami. This research provides information regarding the specific flavor attributes that differentiate chicken and beef products and provides the first set of descriptors that can be associated with “beefy” notes.
Potential Application: The use of a standardized flavor lexicon will allow meat producers to identify specific flavors present in their products. The impact is to identify and quantify negative and positive flavors in the product with the ultimate goal of optimizing processing or cooking conditions and improve the quality of meat products.
Large increases in counts cf Leuconostoc spp., Lactobacillus coryneformis, Lactobacillus plantarum, Lactobacillus viridescens and Lactobacillus curvatus occurred over a 28-d display period when aseptically fabricated steaks were inoculated with 103 to 104 cells/cm2 of these species and then were vacuum-packaged. With Lactobacillus cellobiosus 2, Serratia liquefaciens or Hafnia alvei as inoculum, increases in count were much smaller. Counts of L. cellobiosus 1, Brochothrix thermosphacta, a Moraxella sp. and Alteromonas putrefaciens of inoculated steaks decreased during display. With a higher inoculum (106 cells/cm2), increases in counts of lactic acid bacteria usually were smaller. Some lactic acid bacteria caused marked decreases (0.2 to 0.5) in the pH of the meat surface. Changes in surface discoloration of uninoculated and inoculated steaks over a 28-d display period were not significant (P>0.05). Off-odor scores of both uninoculated and inoculated steaks were lower (more off-odor) after display but few...
as sulfmyo- globin. Theconversion ofmyoglobin tosulfmyoglobin resulted fromtheproduction ofH2Sbybacteria tentatively identified asPseudomonas mephitica. Thisorganism produced H2Sonlywhentheoxygentension wasabout 1%OandthepHofthemeat was 6.0andabove. During thestorage offresh meat,greendis- colorations havebeenobserved, whicharenor- mallyattributed tosulfmyoglobin, cholemyo- globin, orverdoheme formation (5). Little defini- tive information isavailable, however, regarding theconditions necessary fortheformation ofany ofthese green pigments onfresh meat. During experiments onpackaging offresh beef, abright green exudate wasoccasionally noticed whenconditions oflow02tension (-1%)were established intheatmosphere surrounding mus- cles ofhighultimate pH (above 6.0). Thispaper reports theidentification ofthis green pigment as sulfmyoglobin andidentifies theH2S-producing organism. The conditions necessary forH2S production bythis organism werealso determined. MATERLALS ANDMETHODS
Meat stored at 1 to 2 C under low oxygen tensions, either in gas-impermeable packs or in controlled atmospheres, occasionally exhibited an undesirable green exudate. The green pigment was identified spectrophotometrically as sulfmyoglobin. The conversion of myoglobin to sulfmyoglobin resulted from the production of H2S by bacteria tentatively identified as Pseudomonas mephitica. This organism produced H2S only when the oxygen tension was about 1% and the pH of the meat was 6.0 and above.
Fresh hamburger was packaged under vacuum or in air in films having different oxygen permeability and stored in a display case at 5 C for 30 days. Bacon was packaged with a laminated material, under vacuum, in air or carbon dioxide, and similarly stored. Aerobic and anaerobic bacterial counts were made at various intervals. In addition, bacon was examined for Clostridium perfringens and lactobacilli. Color changes also were evaluated.
Bacterial numbers increased on hamburger with either packaging method. However, growth of aerobes on vacuum-packaged meat was slower than growth on meat packaged in air. Anaerobes increased in numbers in hamburgers in evacuated packages after 3 days in storage and after 6 days in meat in unevacuated packages.
Packaging bacon in carbon dioxide resulted in reduction of total numbers of aerobes and lactobacilli. Few C. perfringens were recovered. Color retention was improved for as long as 30 days with either vacuum or CO2 packaging, as compared with air controls.
In general, growth of anaerobes occurred earlier on fresh meat packaged under vacuum than in air; the converse was true for aerobic bacteria. Carbon dioxide inhibited bacterial growth on packaged bacon and provided good color retention during storage.
This chapter focuses on the profile method of flavor analysis and tabulates the flavor methodology. The flavor profile marks a step in the development of the field of sensory flavor testing. It was designed as an additional aid in solving flavor problems. Like other techniques of taste testing, the profile was developed to meet needs arising in the expanding food industry. To see the flavor profile's relationship to the various flavor-testing approaches and to understand its origin and purpose, it is necessary to look briefly at the development of the field of analytical sensory flavor testing. The flavor profile of a food almost invariably includes two parts: analysis of the aroma, followed by analysis of the flavor-by-mouth. The dimensions of flavor analysis by the profile method include: perceptible aroma and flavor factors; degree of intensity of each factor; order in which these factors are perceived; aftertaste; and overall impressions of aroma and flavor, referred to as amplitudes. Two types of flavor profile records have been employed. Both provide the same information.
When cured bacon was exposed to the air the metmyoglobin (MetMb) induced was reconverted to nitrosylmyoglobin (NOMb) by repacking the bacon in vacuo and storing the packs for 1–2 weeks at 5°C. the experimental evidence suggested that NOMb formation involved MetMb reduction by NADH formed from NAD+ and lactate by lactate dehydrogenase (EC 1.1.1.27). All the components of this system were found to be present in bacon. the observation was supported by experiments showing in vitro NOMb formation using lactate dehydrogenase, NAD+, MetMb and nitrite at pH values normally found in bacon.
Focuses on the attitudes of buyers in Europe to Britain, and on their experience of British marketing competence. Examines the more general aspects of reputation followed by the more specific aspects of technical and commercial competence of British companies. Presents suggestions where Britain could improve both its image and reputation.
U.S. Choice grade beef loins and ribs were aged to determine the effect of vacuum packaging for 7 and 15 days at 32° and 40° F on sensory characteristics, microbial counts and weight loss. Vacuum packaging had no significant influence on tenderness, flavor and juiciness but produced a highly significant reduction in weight loss during aging. Surface bacterial counts were significantly less on the vacuum packaged portions than the portions not packaged.
Vacuum packaged beef strip loins (n = 72) were stored (2 ° 1°C) for either 0, 12 or 24 days before fabrication; steaks were packaged and displayed (2°C or 7°C) up to 6 days in oxygen-permeable film or up to 30 days in vacuum packages (medium or high oxygen-barrier film). Steaks displayed at 2°C, rather than 7°C, tended to have higher overall appearance scores especially when steaks were from 12 or 24 day subprimals. Overall palatability of vacuum packaged steaks was unacceptable after 10–15 days of display. Vacuum packaged steaks can be displayed for 10 days if: (1) steaks are from relatively fresh subprimals, (2) steaks are vacuum packaged with high oxygen-barrier film, and (3) steaks are displayed at 2°C. Although visual scores for vacuum packaged steaks were acceptable for 20–30 days, off-odors and off-flavors were limiting factors in determining shelf-life.
Vacuum packaged beef strip loins (n = 72) were stored (2° 1°C) for either 0,12 or 24 days before fabrication; steaks were packaged and displayed (2°C or 7°C) up to 6 days in oxygen-permeable film or up to 30 days in vacuum packages (medium or high oxygen-barrier film). For steaks displayed in oxygen-permeable film, Pseudomonas spp. were a considerable (25–49%) or dominant (>50%) part of the microflora. The microflora of vacuum-packaged steaks from 0 day loins was dominated by a combination of hetero- and homofermentative Lactobacillus spp.; when vacuum-packaged steaks were from 12 and 24 day loins, the microflora was in most cases dominated by the heterofermentative Lactobacillus cellobiosus.
Effects of fat level (14, 19, 24%) and cooking method (electric broiling, charbroiling, conventional oven roasting, convection oven roasting, electric grill frying, microwave cooking) were evaluated with ground beef patties using descriptive attribute and texture profile panels. Higher tenderness and juiciness values were associated with higher fat levels in the patties. Texture profile evaluation indicated the higher tenderness associated with higher fat levels and conventional oven roasting to be due to less hardness, density and cohesiveness during initial biting of the sample. Microwave cooking produced low sensory panel ratings regardless of fat level, while patties cooked by frying had the highest ground beef flavor intensity scores. Major textural properties of cohesiveness, hardness and density were influenced by fat level in a similar manner for all cooking methods.
The spoilage of vacuum-packaged fresh beef during storage at 5°C was studied using analytical taste panels. In the absence of contaminating micro-organisms, meat spoiled due to the development of an “off” flavor described as “liver-like.” This occurred even when the meat was packaged in bags made of film of very low oxygen permeability, but the rate of spoilage increased as the film permeability increased. Thus, vacuum-packaged beef has a limited shelf life even in the absence of a significant population of contaminating microorganisms. Pure cultures of lactic acid bacteria increased the rate of spoilage, which was then due largely to the development of flavor defects described as sour, acid and bitter. Depending upon the strain of bacteria chosen, off flavor became significant 13—28 days after the population reached 108/cm2.
Growth curves were obtained for numbers of organisms surviving on beef stored at 0°, 5°, 10°, 15°, 20° and 25° C. These were related to the development of off-odor and slime. It was shown that the initial load of organisms determined the time required for development of slime. The critical value for slime production was found to be 6 × 107 organisms or a log value of 7.8. There was a change in slope for the effect of temperature at 0° C when compared with that of 20° C.
Comparison was made of the swab, rinse and cut-section methods of sampling; swab samples were selected as being the most reproducible and most convenient to use.
The effect of storage time and temperature on percentages of lipolytic, gelatin liquefying, oxidase producing, chromogenic and fluorescent bacteria was studied. Most of the bacteria on stored meats had lipolytic activity; from one-third to two-thirds of the organisms liquefied gelatin. Oxidase production could not be determined accurately. From 4-20% of the initial population were found to be chromogens but colored colonies were rarely found beyond the fourth day of storage; also, plates stored at temperatures less than 15° C did not yield chromogens. Fluorescent bacteria comprised 10-25% of the flora throughout storage.
Microorganisms isolated from refrigerated beef were classified and it was found that at 10° C or lower the bacteria responsible for production of slime were almost without exception pseudomonads. Various species of Pseudomonas were identified. At 15° C or above, there was approximately an equal incidence of organisms of the genus Micrococcus and Pseudomonas. Other bacteria that were recovered from the sliced meat were Achromobacter, Flavobacterium, Microbacterium, Alcaligenes, Aeromonas, Bacillus, Clostridium and Streptococcus. Species of Penicillium were the most commonly encountered molds, more rarely, Cladosporium, Thamnidium, Mucor, Rhizopus, Aspergillus, Alternaria, and Sporotrichum were found.
At chill temperatures the spoilage flora of meat is composed of psychrotrophs originating largely from the hides of slaughtered animals. Under humid conditions, aerobic floras are usually dominated by pseudomonads while anaerobic floras are dominated by lactobacilli. In both cases growth occurs on low molecular weight soluble components of meat which are attacked in the order glucose, glucose-6-phosphate (Enterobacteriaceae only) and amino acids. Under aerobic conditions spoilage becomes detectable when the bacteria begin to degrade amino acids which remain abundant at the meat surface when growth ceases, probably because of limited availability of oxygen. Under anaerobic conditions growth ceases because the diffusion of fermentable substrates to the surface is not rapid enough to support further growth. Aerobically, there is no interaction between different bacterial species until the maximum cell density is approached; anaerobically, however, lactobacilli produce an antimicrobial agent which inhibits growth of competing species. The composition of spoilage floras can be affected by changes in water activity and the storage atmosphere.
Joints of beef were stored in packaging films with oxygen permeabilities ranging from 0–920 ml/m224 h/atm at 25 °C and 100% r.h. The storage life of the ‘vacuum-packaged’ meat, as assessed by discolouration and the development of putrefactive odours, was inversely related to film permeability; the best results were obtained with meat which received ‘zero oxygen’ treatment. The growth rates and final counts of Pseudomonas spp. increased with increasing film permeability; the storage life of the meat corresponded with the time taken for the counts of the organism to reach ca. 106/cm2 for putrefactive odours to be produced. Although their growth rate was unaffected, the final counts of Brochothrix thermosphacta also increased with increasing film permeability. These results are discussed in terms of the influence of film permeability on the inhibitory effects of Lactobacillus spp., whose numbers were unaffected by the permeability of the film used, and the substrates in the meat available to the bacteria.
The development of the microbial flora on meat stored in vacuum-bags at 0–2° for up to 9 weeks was studied. Although the proportion of lactic acid bacteria increased relative to the aerobic spoilage organisms, the numbers of the latter continued to increase throughout storage. The initial contamination of the meat before vacuum-packaging was important; meat with a very low initial number had lower numbers of bacteria throughout storage for up to 9 weeks and steaks cut from such meat which had been stored always had 1–2 days’ additional aerobic shelf life at 4°. Spoilage of these steaks was due either to slime formation and off-odour associated with high counts of presumptive Pseudomonas spp., or by discoloration and souring (lactic acid bacteria). Extract release volume and pH measurements performed on the vacuum-packaged primal joints were only of value in determining the onset of aerobic spoilage when large numbers of Gram negative organisms were present, whereas the titrimetric method of spoilage evaluation of the vacuum-packaged meat showed a correlation with spoilage due to lactic organisms.
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