SOME EFFECTS OF SODIUM LACTATE ON SHELF-LIFE, SENSORY, AND PHYSICAL CHARACTERISTICS OF VACUUM-PACKAGED BEEF BOLOGNA

Beef bologna, containing 0, 1, 2, or 3% sodium lactate (SL), was vacuum packaged and stored at 4C for 0, 2, 4, 6, 8, and 10 weeks. Color was assessed using L*, a*, b* measures, and fade (% reflectance 570 nm/650 nm). A trained sensory panel evaluated flavor and color intensity. Total aerobic plate counts (TPC), pH, and TBA values were determined. Addition of SL had no effect on initial pH. Pink color was correlated with a* values, fade, and TPC (r = 0.74, -0.70 and -0.54, respectively; p < 0.05). Salty-flavor intensity was highest for bologna containing 3% SL and lowest in controls. Beefy flavor was inversely correlated with TPC (r = -0.45, p < 0.05). Sour-flavor scores were inversely correlated with pH (r × -0.51) and directly with TPC (r = 0.33, p < 0.05). After 10 weeks TPC for control product was highest, while that for bologna containing 3% SL was lowest.     

DETERMINATION OF FIRMNESS AND SUGAR CONTENT OF APPLES USING NEAR‐INFRARED DIFFUSE REFLECTANCE1

The objective of this research was to study the potential of near‐infrared (NIR) diffuse reflectance between 800 nm and 1700 nm for determining the firmness and sugar content of apples and to ascertain the effects of apple peel and variety on the NIR prediction of these two quality attributes. The spectral reflectance data were acquired from both peeled and unpeeled ‘Empire', ‘Golden Delicious', and ‘Red Delicious’ apples. Statistical models were developed using principal component analysis/regression. Lower correlations of prediction were obtained (r=0.38 to 0.58) between NIR measurement and Magness‐Taylor firmness for both unpeeled and peeled fruit, with the standard errors of prediction (SEP) between 6.6 N and 10.1 N. Improved predictions were obtained when NIR reflectance was correlated with the slope of the Magness‐Taylor force‐deformation curves. Excellent predictions of the sugar content in peeled apples were obtained (r=0.93 to 0.97; SEP=0.37 to 0.42 °Brix). The SEP, on average, increased by about 0.17 °Brix for the unpeeled apples. Variety did not have a large effect on the model performance on sugar content predictions.     

RESTRUCTURED PORK WITH FLAVOR ENHANCERS

Muscles were removed from pork shoulders at 24 h postmortem and converted to restructured chops. Flavor enhancers included in the formulations were 0.5% mushroom extract (M), 0.38% Globe Natural Potentiator (NP), 0.38% monosodium glutamate (MSG), and no flavor enhancers (C). At 0, 14, and 56 days after packinging, samples were evaluated for discoloration, cohesiveness, muscle cut resemblence, overall appearance, juiciness, connective tissue amount, tenderness and flavor. Objective evaluations included Hunter Color and TBA values. Samples with MSG sustained less discoloration (P< 0.05), when measured objectively and subjectively, after storage for 42 days than the M and NP chops. Similar effects on overall appearance scores were noted. All flavor enhancers had a minimal effect on cohesiveness, muscle cut resemblance, juiciness, connective tissue amount and tenderness. The mushroom extract and the Globe Natural Potentiator provided more flavor protection than monosodium glutamate.     

Fibre-optic spectrophotometry for predicting lipid content, pH and processing loss of comminuted meat slurry

A fibre-optic light guide was used to measure the internal reflectance (interactance from 400 to 1000nm) of slurries of comminuted meat. For mixtures of pork adipose tissue and beef muscle with a low connective tissue content, internal reflectance at 1000nm was correlated with lipid content ( r =0.99, P <0.005) and with cooking loss ( r =0.99, P <0.005), and at 930nm with centrifugation fluid loss ( r =0.77, P <0.005). For pork muscle varying in pH but adjusted to a constant lipid content, internal reflectance at 780nm was correlated with pH ( r = -0.80, P <0.01), at 690nm with centrifugation fluid loss ( r =0.74, P <0.025) and at 710nm with cooking loss ( r =0.63, P <0.05). The additive nature of these correlations favours the use of internal reflectance to predict the functional properties of meat slurries.     

Imaging optical diffuse reflectance in beef muscles for tenderness prediction

The objective of this study was to investigate the potential of a novel optical reflectance imaging method to predict beef tenderness. Two-dimensional (2D) optical reflectance in beef muscles induced by a point incident light was acquired. A set of five parameters were extracted from each reflectance image to describe quantitatively the reflectance profiles. Two parameters, q and B, were derived by numerically fitting the equi-intensity contours of the reflectance pattern. Two spatial gradients were calculated along the directions parallel and perpendicular to muscle fibers and total scattering intensity was obtained by excluding the specular reflectance. This method was applied to analyze 2D images of optical diffuse reflectance in 336 beef samples obtained from 14 steers in which large variations in tenderness were generated by altering animal genetics, suspension method and aging time as well as utilizing muscles varying in their inherent tenderness. Tenderness was evaluated using Warner–Bratzler shear force (WBSF). The effects of animal breed, muscle, types of suspension, and aging were investigated and results indicate that the scattering intensity measured at 1-d was correlated (R² = 0.50 at λ = 720 nm) with 10-d WBSF in M. longissimus dorsi muscles; and the q parameters measured at 1-d was correlated (R² = 0.46 at λ = 720 nm) with 10-d WBSF in M. psoas major muscles. These results show analyzing 2D reflectance images of meat surfaces provides valuable information regarding the physical characteristics of meat that are responsible for beef tenderness.     

Light Transmission Characteristics of Wrapping Materials and Oxidation of Butter by Fluorescent Light

Butter was wrapped in 10 materials as 454-g prints and exposed to Cool-White fluorescent light. Four treatments were different combinations of light intensity and time (lx/d, 400/1, 400/6, 2000/2, 2000/4). The wappers were 5 polyethylene-based plastics, 2 parchment papers, 2 metallized aluminum papers, and an aluminum foil paper laminate. Only the laminate completely protected butter from oxidation. Oxidation occurred on the light-exposed butter surface with all wrappers in the three strongest light treatments. There were linear relations of the level of oxidized flavor with flavor score (r = −.99) and of logarithms of peroxide values with oxidized flavor and with flavor scores (r = .90 and −.91, respectively). Oxidation was similar whether butter was fresh or stored at −18°C for 8 mo before light exposure. After 2000 lx for 4 d and storage for 8 to 12 wk, oxidized flavor had penetrated 20 mm, or one-third, of the print.Wrappers differed markedly in their transmission of light. The foil laminate transmitted no measurable light. Yellow plastics transmitted very little light below 500 nm; this did not appreciably reduce oxidation, indicating that longer wavelengths are important. Values for peroxide on the surface with the different wrappers and light treatments were linearly related to the logarithm of light intensity and to the square root of time. Thus, oxidation was greater at lower intensities of light and at shorter times of exposure than expected from that observed at higher intensities and longer time exposures. The 2 metallized papers transmitted less than 10% of light and did not prevent oxidation, indicating that wrappers should transmit even less light for protection of butter from the higher light exposures used in this trial.     

Hind-limb protein metabolism and calpain system activity influence post-mortem change in meat quality in lamb

This study is concerned with the rate of protein turnover in the hind limb muscle bed of intact lambs, the activity of calpain proteolytic system in the M. biceps femoris, and subsequent rates of myofibre breakdown and tenderisation in the M. longissimus dorsi. Feed restriction increased protein degradation in hind-limb muscle of lambs (p<0.1), with a concominant decrease in the extractable activity of calpastatin (p<0.01), the endogenous inhibitor of calpain. IGF-1 analog treatment decreased both protein degradation and assayed μ-calpain activity (p<0.05) with no effect on the activity of calpastatin. β-Agonist treatment increased hind-limb protein synthesis (p<0.01), calpastatin activity (p<0.1) and decreased (p<0.01) μ-calpain activity, but did not effect protein degradation. Significant correlations were observed between Myofibril Fragmentation Index (MFI) values during post-mortem storage and initial post-slaughter calpastatin activity at days 3 (r=-0.34, p<0.1), 5 (r=-0.58, p<0.01) and 9 (r=-0.58, p<0.1), and μ-calpain activity at days 5 (r=0.35, p<0.1) and 9 (r=0.41, p<0.05). However, stronger correlations were observed between the ratio of μ-calpain to calpastatin, an estimate of potential μ-calpain proteolytic activity, and the rate of myofibril fragmentation (r=0.75, p<0.001) and tenderisation (r=-0.64, p<0.01) during aging. These results are consistent with the calpain system being the major proteolytic system involved in myofibril fragmentation and hence aging-related tenderisation of meat.     

Relationship of texture profile analysis and Warner-Bratzler shear force with sensory characteristics of beef rib steaks

Cyclical texture profile analysis (TPA) parameters measured using a star-shaped probe with two cycles of 80% penetration and Warner-Bratzler shear force (WBS) were compared as predictors of objective tenderness and subjective sensory characteristics of rib steaks from 52 beef loins. The TPA parameters of hardness, cohesiveness and chewiness were negatively correlated (P<0.05) with trained panel sensory characteristics of initial tenderness (r=−0.64, −0.41, −0.62, respectively), amount of connective tissue (r=−0.57, −0.27, −0.55, respectively), overall tenderness (r=−0.68, −0.39, −0.64, respectively) and overall palatability (r=−0.56, −0.37, −0.53, respectively). These sensory characteristics were also negatively correlated (P<0.05) with WBS (r=−0.61, −0.49, −0.60, −0.56, respectively). Stepwise regression analysis generated prediction equations that included the TPA parameters of hardness and adhesiveness, which accounted for 47, 36, 51 and 38% of the variation in initial tenderness, amount of connective tissue, overall tenderness and overall palatability, respectively. Prediction equations using WBS accounted for 37, 24, 36 and 31% of the variation in initial tenderness, amount of connective tissue, overall tenderness and overall palatability, respectively. Hence, TPA explained more of the variation in subjective sensory tenderness of the rib steaks than WBS.     

Prediction of color, texture, and sensory characteristics of beef steaks by visible and near infrared reflectance spectroscopy. A feasibility study

Color, instrumental texture, and sensory attributes of steaks from 24 beef carcasses at 2, 4, 8, 14, and 21 days post mortem were predicted by visible/near infrared (visible/NIR) reflectance spectroscopy in 400-1080 nm region. Predicting the Hunter a, b, and E* yielded the coefficient of determination (R(2)) in calibration to be 0.78-0.90, and R(2) was between 0.49 and 0.55 for tenderness, Hunter L, sensory chewiness and juiciness. The prediction R(2) for tenderness was in the range of 0.22-0.72 when the samples were segregated according to the aging days. Based on partial least square (PLS) model predicted tenderness, beef samples were classified into tender and tough classes with a correct classification of 83%. Soft independent modeling of class analogy of principal component analysis (SIMCA/PCA) model of measured tenderness showed great promise in the classification of tender and tough meats with over 96% success.     

Relationships between post-mortem pH changes and some traits of sensory quality in veal

The aim of this study was to evaluate the relationships between the rate and extent of post-mortem pH changes and the colour, the cooking loss and the eating quality of veal. The experiment used 12 calves aged 18 weeks. Variations in ultimate pH were induced by adrenalin administration (0.1–0.4 mg/kg liveweight) to six of the animals. Measurements were made on the Longissimus thoracis muscle. pH and osmotic pressure were measured at 0.5 h, 4 h and 29 h after slaughter. Pigment content, drip loss and cooking loss were measured at 29 h after slaughter, and colour was measured at 2 days and 9 days after slaughter. Cooking loss, tenderness, juiciness and flavour of roasts were assessed at 9 days after slaughter.

Correlations between colour traits and pH values were higher with ultimate pH than with pH at 0.5 h or 4 h after slaughter. Lightness, redness and reflectance decreased when the ultimate pH increased. Drip loss was correlated with the rate of pH fall (r = −0.80, P < 0.01 with pH at 4 h), while cooking loss was correlated with ultimate pH (r = −0.94, P < 0.01). Ultimate pH and the sensory quality traits were linearity and positively correlated (r = 0.83) for tenderness, 0.81 for juiciness and 0.71 for flavour, respectively).     

PORK SOFTNESS ASSESSED SUBJECTIVELY AND OBJECTIVELY USING VACUUM-INDUCED CHANGES IN REFLECTANCE

Subjective assessments were made of softness and paleness in longissimus muscles of 382 sides of pork. Softness was correlated with paleness, (r = 0.57, P < 0.001). Softness was tested objectively in another 48 pork loins by applying a vacuum (to −2 kPa) across an elliptical area of longissimus. Reflectance from the meat surface measured by fiber-optics increased as the meat bulged outwards toward the vacuum. Pale pork was deformed to a greater extent than dark pork, and the initial slope of the reflectance-pressure relationship was correlated with initial reflectance before deformation and with maximum reflectance during deformation. At the maximum extent of deformation, there was a decrease in reflectance if the meat touched the fiber-optic light guide. By spectrophotometry of another 19 loins, the major difference between reflectance at 0 kPa and ≤−2 kPa was found at 470 nm.     

Retail display evaluation of steaks from select beef strip loins injected with a brine containing 1% ammonium hydroxide. Part 2: Cook yield, tenderness, and sensory attributes

The impact of 2 different brines on the palatability and tenderness of select beef strip loin steaks was evaluated. Brines were differentiated by the type of alkaline agent, 4.5% sodium-based phosphate (control brine; CON) or 1% ammonium hydroxide (ammonium hydroxide treatment; AHT), incorporated into the formula. Injected steaks were placed in high oxygen (80% O(2)/20% CO(2)) MAP, stored 4 d at 4 °C in dark storage to simulate transportation, and then placed in retail display. Steaks were selected randomly on day 0, 7, and 14 retail display to measure pH, cook loss, shear force, and sensory characteristics. The pH for AHT steaks (pH 5.96) was slightly higher than CON steaks (pH 5.86; P < 0.05). Cook loss was lower (21%) for CON than AHT steaks (23%). There was neither a treatment nor day effect on tenderness as measured by Warner-Braztler shear force (P > 0.05). Sensory evaluation indicated that on day 0, retail display the initial juiciness, sustained juiciness, tenderness 1st impression, tenderness overall impression, and connective tissue in AHT steaks was not different from CON steaks (P > 0.05). A day effect (decrease) for those sensory parameters was observed only for sustained juiciness (P < 0.05). AHT steaks were rated higher in cooked beef flavor while CON steaks were higher in peppery and salty flavor. There was no difference in soapy and ammonia intensity between treatments. Results indicated that despite lower performance in cook loss the replacement of 4.5% sodium-based phosphate in a meat injection brine with 1% ammonium hydroxide produced a beef loin steak with comparable tenderness and palatability. Practical Application: The research in this study compares steaks that have been injected with a commercial brine formulated with sodium phosphates to steaks that have been injected with a brine where the sodium phosphate in the formulation was replaced with 1% ammonium hydroxide. Ammonium hydroxide is an USDA-FSIS approved ingredient in brines injected into fresh meats. Successful replacement of sodium phosphate with ammonium hydroxide would allow processors to significantly reduce the sodium content of injected fresh meat.     

Ultrasonic Spectral Analysis for Beef Sensory Attributes

Ultrasonic spectral feature analysis was conducted for measuring beef sensory attributes noninvasively. Spectral features were compared with instrumental texture, chemical and sensory evaluation measures. The most significant (P <0.05) ultrasonic parameter was the number of local maxima for juiciness (ρ=0.49), connective tissue amount (ρ=0.52), flavor intensity (ρ=0.39), percent total collagen (ρ=0.34), and shear force (ρ=0.51). However, the central (resonant) frequency was the most dominant parameter for tenderness (ρ=0.45; P <0.05). Multivariate linear regression models were developed for predicting each palatability attribute. Standard errors of calibration for models were 0.253 for juiciness, 0.745 for muscle fiber tenderness, 0.244 for connective tissue amount, 0.754 for overall tenderness, and 0.224 for flavor intensity. Accuracy of prediction models was not adequate for use as a tool but this approach has potential for nondestructive sensory attribute measurement.     

Palatability and Storage Characteristics of Precooked Beef Roasts

The palatability and storage characteristics of fresh, frozen and precooked beef chuck roasts prepared using added phosphate-salt and vacuum cooking bags were evaluated. Palatability attributes (tenderness, juiciness, beef flavor intensity, and off-flavor intensity) of precooked roasts prepared in vacuum cooking bags with phosphate-salt were as good or better than freshly cooked roasts. Precooked roasts in vacuum cooking bags had the lowest total bacterial counts after storage for 14 and 28 days. A palatable precooked roast beef product was developed that can be stored for 28 days at 4°C.     

Effects of quality grade on the chemical, physical and sensory characteristics of Hanwoo (Korean native cattle) beef

The effects of quality grade (which reflects relative marbling) on the chemical, physical and sensory properties was investigated using Korean native cattle (Hanwoo) beef. Thirty-six Hanwoo cows were slaughtered and the carcasses were graded at 24h postmortem according to the Korean carcass grading system. The quality grade 1 (high quality), grade 2 and grade 3 (low quality) were based on the marbling score of longissimus dorsi (LD) muscles. The effects of quality grade on the meat quality parameters of beef LD muscle were assessed during aging. Loin-eye area, fat thickness and yield grade were all similar for the three quality groups. Mean lean color, fat color and maturity scores did not differ among quality grade groups (P>0.05). pH, Sarcomere length, WHC, collagen content, cooking loss, shear force and MFI were not affected by quality grade groups. Drip loss for grade 1 group was significantly lower than that for grade 3 groups (P<0.05). At initial tenderness evaluation of steaks, no differences among the three grades were observed; however, with additional days of storage, grade 1 steaks had higher tenderness score than grade 3 steaks (P<0.05). Increased postmortem aging time improved tenderness attributes regardless of quality groups. No significant differences were found among the quality grade groups for flavor (P>0.05). The grade 1 group had the highest juiciness score, and grade 3 groups had the lowest score (P<0.05), but postmortem aging did not influence flavor and juiciness. The quality grades were more strongly related to juiciness than tenderness or flavor.     

Effects of Blade Tenderization, Vacuum Mixing, Salt Addition and Mixing Time on Binding of Meat Pieces into Sectioned and Formed Beef Steaks

Meat pieces (2–3 cm cubes) from A maturity, Standard grade beef rounds were processed into sectioned and formed steaks. Processing treatments were blade tenderization and no blade tenderization, vacuum and no vacuum mixing, 0.5% salt and no salt addition, and 0, 8, 16, and 24 mm mixing times. Thiobarbituric acid (TBA) was used to indicate rancidity, Instron adhesion to evaluate bind between meat pieces, Instron-Kramer shear to evaluate steak tenderness, and a trained sensory panel to evaluate initial and overall tenderness, connective tissue residue, juiciness and flavor. The TBA values were higher in steaks with 0.5% salt after 90 days of storage while no differences were shown between mixing times. Cooking losses were lower after 24 min mixing. Mixing for 16 min increased binding and improved tenderness. Juiciness and flavor were not influenced by mixing time. Meat pieces mixed for 16 min with 0.5% salt produced the best sectioned and formed steaks.     

RESTRUCTURED PORK WITH TEXTURE VARIATION

Muscles were excised from the shoulders of U.S. No. 1 pork carcasses within 1h postmortem. Samples were flaked as; small (head opening = 3.0mm), medium (head opening = 6.1mm) and large (head opening = 9.9mm) with an Urschel Comitrol 3600. Samples were formulated with 1.0 NaCl and 0.25% sodium tripolyphosphate (STP), converted into 19 mm thick restructured chops and packaged. Subjective evaluations were conducted after 5 and 56 days of frozen storage for color, cohesiveness, muscle cut resemblance, overall appearance, tenderness, juiciness, connective tissue amount and flavor. Objective measurements included Hunter Color values, shear force, percentage cooking loss and Thiobarbituric Acid (TBA) values. Results suggested that large flaked particles contributed to improved color and reduced cooking loss. Particle size had no effect on muscle cut resemblance, overall appearance, juiciness and flavor. Increased particle size was responsible for decreased tenderness, cohesiveness and TBA values but increased connective tissue amount.     

The eating quality of Canadian pork and its relationship with intramuscular fat

This study was undertaken to assess the effect of various levels of intramuscular fat (IMF: <1%, 1.0-1.49%, 1.5-1.99%, 2.0-2.49% and 2.5-3.0%) produced from Canadian pigs on the eating attributes of pork loin. Sensory and instrumental eating attributes were determined on 85 pork loins (m. longissimus lumborum and thoracis). The following correlations were found between IMF and eating attributes: softness, -0.32 (P<0.01); initial tenderness, -0.31 (P<0.01); chewiness, -0.27 (P<0.01); rate of breakdown, -0.20 (P=0.07); juiciness, 0.17 (P>0.05); flavour intensity, 0.24 (P=0.02); off-flavour, 0.13 (P>0.05); mouth coating, 0.13 (P>0.05); amount of perceptible connective tissue, -0.02 (P>0.05), and instrumental tenderness (Warner-Bratzler shear force), -0.41 (P<0.001). As tenderness is considered the most important attribute that determines overall acceptance of pork, the threshold level of IMF for ensuring a positive eating experience was identified as a function of the attributes describing tenderness. Increasing the level of IMF past 1.5% did not change (P<0.05) the panelists scores for softness and initial tenderness. Average shear force, an instrumental measure of tenderness, was higher (P<0.05) at less than 1% IMF but did not change past 1.0% IMF (P>0.05). It is proposed that the threshold level of IMF that will ensure a pleasing eating experience is 1.5% IMF.     

The influence of mechanical tenderization on the palatability of certain bovine muscles

Twelve different muscles or muscle groups were removed from both sides of 25 Canada AA beef carcasses. Muscles or muscle groups from alternate carcass sides were either mechanically tenderized or served as controls. Mechanical tenderization increased thaw-drip losses from the brisket approximately 1.25% and cooking losses from the blade eye by approximately 2.75%, but did not influence cooking times. Mechanical tenderization also improved initial and overall tenderness of the outside round, top sirloin, striploin, inside round and chuck tender. In addition initial tenderness of the sirloin tip eye and overall tenderness of the eye of the round were improved by mechanical tenderization. Moreover, connective issue in the top sirloin, striploin, and eye of the round was less perceptible after mechanical tenderization, but juiciness was decreased in the blade eye and top sirloin. Flavor intensity of the top sirloin and rib-eye was also reduced by mechanical tenderization. However, the desirability of the flavor of the inside round was improved by mechanical tenderization and the overall palatability of the inside round and eye of the round improved with mechanical tenderization. Mechanical tenderization decreased the proportion of inside round samples rated tough initially and overall from 52 to 20% and from 36 to 12% respectively. Mechanical tenderization also reduced the proportion of outside round samples perceived to contain a slight or greater amount of connective tissue from 36 to 12%. In addition, mechanical tenderization reduced the proportion of inside round samples with undesirable flavor from 16 to 0% and reduced the proportion of unpalatable rib-eye, inside round, and eye of the round samples from 12 to 0, 36 to 8 and 80 to 40%, respectively. Consequently, mechanical tenderization can be effectively utilized to reduce the variability and improve the tenderness and palatability of certain muscles, particularly hip muscles.     

MECHANICAL MEASUREMENTS OF MEAT TENDERNESS USING THE NIP TENDEROMETER

Abstract. A series of evaluations to compare the sensory panel ratings for tenderness with the Warner-Bratzler shear force and the Nip Tenderometer values was conducted using 150 pork chops, 239 lamb chops and 674 beef steaks. The Warner-Bratzler shear force values were more highly correlated with panel tenderness ratings than were the Nip Tenderometer readings for samples of pork, lamb and beef tested after cooling to room temperature (23 °C). Nip Tenderometer determinations on hot samples of beef (75 °C) were more closely related to panel tenderness ratings ( r =— 0.80) than were Nip Tenderometer readings ( r =— 0.58) or shear force values ( r =— 0.63) obtained on cold samples (23 °C). The combined advantages of ease and speed of application, correlation with sensory panel ratings and the demonstrated accuracy in identifying 'tough' vs 'tender' steaks suggest that the Nip Tenderometer has potential as an objective means for evaluating meat tenderness.