This paper is a product of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa, USA, Project No. IOW03721, which is sponsored by Hatch Act and State of Iowa funds.
The effects of citrus fiber on the color, texture, lipid oxidation, and sensory characteristics of fully cooked deli-style turkey breast during storage (3°C) were studied. Four treatments were evaluated: control, 0.25% citrus fiber, 0.50% citrus fiber, and 0.105% sodium tripolyphosphate. The study was independently replicated 3 times. Proximate analysis and pH were measured once, and color (Hunter L, a, b), lipid oxidation (thiobarbituric acid-reactive substances), texture (Texture Profile Analysis hardness, resilience, cohesiveness, springiness, and chewiness), and sensory parameters (turkey aroma, texture, moistness, turkey flavor, off-flavor, and color) were measured at regular intervals on vacuum-packaged samples throughout an 84-d storage period. Aside from Texture Profile Analysis resiliency and sensory moistness lower in the 0.105% sodium tripolyphosphate group, all experimental treatments resulted in product with equivalent quality attributes to the control. At the levels tested in this specific application (high moisture, low fat), the citrus fiber evaluated did not affect the product’s quality attributes in a measurable way.
In the last decade, growing skepticism from some consumers regarding food additives has created a demand and market for so-called “clean label” products. The term “clean label,” though it does not have a widely agreed-upon definition, is generally given to products devoid of ingredients that must be declared on their labels by their common chemical names (
Phosphates increase myofibrillar swelling and improve water-holding capacity by increasing pH and ionic strength and facilitating protein extraction (
Different fibers and high-fiber ingredients have the potential to be used as alternatives to phosphates or other binder ingredients because of their high surface area, which can contribute to improved water retention, processing yields, and texture. Defined as “the remnants of plant cells resistant to digestion by human enzymes…whose components are hemicellulose, cellulose, pectin, lignin, oligosaccharides, gums, and waxes” (
The objective of this study was to evaluate the effects of citrus fiber addition on the physical, chemical, and sensory properties of fully cooked deli turkey over a storage period of 84 d.
The sensory analysis protocol used in this study was reviewed and approved by the Iowa State University Institutional Review Board (16 November 2016; IRB ID 16-527), and informed consent was obtained from all panel participants prior to initiation of the study.
Frozen turkey breasts (
Approximately 1 week before manufacture, frozen turkey breasts were delivered to the Iowa State University Meats Laboratory and stored frozen at −40°C. As needed, meat was thawed at 4.4°C for 2 d and then moved into a cooler at 0°C–1°C for 1 d. On the day of production, injection brines were prepared according to the formulations shown in Table
Injection brine formulations of oven-roasted turkey breast (percentage basis)
CON | 0.25CF | 0.50CF | PHO | |
---|---|---|---|---|
85.45 | 83.95 | 82.45 | 84.83 | |
8.40 | 8.40 | 8.40 | 8.40 | |
3.75 | 3.75 | 3.75 | 3.75 | |
2.10 | 2.10 | 2.10 | 2.10 | |
0.00 | 0.00 | 0.00 | 0.63 | |
0.00 | 1.50 | 3.00 | 0.00 | |
0.25 | 0.25 | 0.25 | 0.25 | |
0.05 | 0.05 | 0.05 | 0.05 |
CON = control; 0.25CF = 0.25% citrus fiber; 0.50CF = 0.50% citrus fiber; PHO = sodium tripolyphosphate.
Thermal processing schedule of cooked deli-style turkey breast
Step | Step Time (min) | Dry Bulb (°C) | Wet Bulb (°C) | Relative Humidity (%) | Main Blower | Exhaust Damper |
---|---|---|---|---|---|---|
1:00 | 60 | 60 | 100 | 5 | Closed | |
0:30 | 66 | 66 | 100 | 5 | Closed | |
0:30 | 71 | 71 | 100 | 5 | Closed | |
0:05 | 82 | 82 | 100 | 5 | Closed | |
0:20 | 10 | 0 | 0 | 0 | Auto |
Fat, moisture, and protein contents were measured in duplicate for each treatment. Fat content and moisture content were measured following Official Methods 960.39 and 950.46 of AOAC International (
Ten grams of sample was ground and mixed with 90 mL of distilled water in a 150-mL beaker and stirred vigorously for 60 s. The mixture was filtered (11-μm filter paper, Whatman Grade 1, GE Healthcare Life Sciences, Pittsburgh, PA), and the pH of the filtrate was read using a SevenMulti pH meter equipped with an InLab Solids Pro-ISM electrode (Mettler Toledo, Columbus, OH). pH readings were done in duplicate and averaged.
The oxidative rancidity of samples stored under retail display conditions was measured on days 0, 14, 28, 56, and 84 by the 2-thiobarbituric acid procedure of Tarladgis et al. (
Color was measured on days 0, 14, 28, 56, and 84 using a HunterLab LabScan XE colorimeter (model LS 1500; Hunter Associated Laboratories, Inc., Reston, VA) using illuminant D65 (daylight at 6,500 K), 10° observer angle, and 2.54-cm aperture. The Hunter L, a, b color space was used. Saran-brand clear plastic film (S.C. Johnson & Son, Inc., Racine, WI) was placed over the calibration tiles to account for the packaging material of retail display samples. Measurements were taken on the surface of all samples at 3 different locations for a total of 3 random surface measurements per sample.
Texture Profile Analysis (TPA) was done in triplicate on days 0, 14, 28, 56, and 84 using a TA-XT2i Texture Analyzer (Stable Micro Systems, Surrey, UK). Unsliced turkey samples were cut to a thickness of 2.54 cm, cored to a diameter of 2.54 cm, and subjected to a simplified TPA test. All instrumental texture analyses were conducted on chilled samples (0°C–1°C). The samples were compressed twice to 35% of their original height at a test speed of 5.00 mm s−1 and a trigger force of 0.049 N. The texture profile parameters hardness, resilience, cohesiveness, springiness, and chewiness were determined as described by Bourne (
Sensory analysis was conducted on days 14, 28, 56, and 84 using a 10-member trained sensory panel. Panel participants were students, faculty, and staff of Iowa State University’s Departments of Food Science and Human Nutrition and of Animal Science. Two separate training sessions were held on different days during the week before the first test session, utilizing samples from this study. By the end of the second session, general agreement was achieved among panel members regarding the definition and magnitude of the sensory attributes evaluated. Every test session, a 3-digit code was randomly assigned to each treatment sample. Prior to serving, sample slices were cut into 8 wedges, and the pieces were placed in a large bowl and mixed to ensure randomization. Four wedges were placed in a cup with a lid and held under refrigeration for approximately 30 min prior to evaluation. Each panelist tested the samples inside a cubicle illuminated with red lights. Water and plain crackers were provided as palette cleanser. For color evaluation, an intact slice of each test sample was placed on white butcher paper and evaluated by the panelists under sunlight next to an exterior-facing window. Panelists recorded their evaluation on a 15-cm line scale, and data were collected using Compusense five (release 5.6) sensory evaluation software (Compusense, Inc., Guelph, ON, Canada). Sensory attributes evaluated were turkey aroma (“none” to “intense”), texture (“soft” to “firm”), moistness (“not moist” to “moist”), turkey flavor (“none” to “intense”), off-flavor (“none” to “intense”), and color (“light” to “dark”). During sample manufacturing, product from replication 1 was accidentally rendered inedible; therefore, sensory analysis was performed on samples from replications 2 and 3 only.
The experiment was designed as a randomized complete block design. For each replication, assignment of experimental treatments to manufacturing batches and placement of stuffed logs for thermal processing were done randomly. The experiment was replicated independently 3 times (twice for sensory analysis), with replications as blocks, and each replication corresponded to a different consecutive manufacturing day. To reduce experimental error by minimizing within-block variation, all raw materials used were from the same production lot.
Data were analyzed as a mixed model using the PROC MIXED procedure of SAS (version 9.4; SAS Institute, Cary, NC), with the fixed factors of treatment, storage time, and treatment × storage time interaction and the random factors of replication, replication × storage time, sensory test sessions, and panelists. Differences between treatments and within treatments over time were determined using the Tukey-Kramer pairwise comparison method. Significance was established at
The proximate composition, pH and cook/chill yields of the cooked deli-style turkey samples are shown in Table
Proximate composition, pH, and cook/chill yield of cooked deli-style turkey
Treatment | Moisture % | Protein % | Fat % | pH | Yield % |
---|---|---|---|---|---|
72.03 | 25.03 | 1.67 | 6.19 | 79.14 | |
72.53 | 24.37 | 1.49 | 6.18 | 81.30 | |
71.59 | 25.07 | 1.54 | 6.09 | 77.14 | |
72.66 | 24.12 | 1.52 | 6.18 | 80.91 | |
0.37 | 0.46 | 0.14 | 0.02 | 0.75 |
Means of 3 replications. All analyses performed in duplicate.
Means in the same column with different letters are significantly different (
0.25CF = 0.25% citrus fiber; 0.50CF = 0.50% citrus fiber; PHO = sodium tripolyphosphate; SEM = standard error of the mean.
Color results—expressed as Hunter L, a, b values—are shown in Tables
Means for effect of treatment on Hunter L, a, b values of cooked deli-style turkey stored in the dark or under retail display lights
Dark | Retail Display | |||||
---|---|---|---|---|---|---|
Treatment | L | a | b | L | a | b |
70.31 | 7.53 | 8.80 | 71.31 | 7.10 | 9.32 | |
70.94 | 7.19 | 9.14 | 71.77 | 6.93 | 9.61 | |
70.21 | 7.46 | 9.40 | 72.65 | 6.49 | 9.69 | |
70.23 | 7.44 | 8.59 | 71.02 | 6.90 | 9.23 | |
0.38 | 0.14 | 0.07 | 0.40 | 0.13 | 0.06 |
Means of 3 replications. All analyses performed in duplicate.
Means in the same column with different letters are significantly different (
CON = control; 0.25CF = 0.25% citrus fiber; 0.50CF = 0.50% citrus fiber; PHO = sodium tripolyphosphate; SEM = standard error of the mean.
Means for effect of storage time on instrumental (Hunter Lab) color values of cooked deli-style turkey stored in the dark or under retail display lights
Dark | Retail Display | |||||
---|---|---|---|---|---|---|
L | a | b | L | a | b | |
0 | 70.06 | 7.48 | 9.34a | 72.07 | 5.80 | 10.98 |
14 | 70.49 | 7.42 | 8.89 | 70.82 | 7.46 | 9.31 |
28 | 70.61 | 7.43 | 8.90 | 71.06 | 7.23 | 9.12 |
56 | 70.52 | 7.34 | 8.92 | 72.32 | 6.92 | 8.89 |
84 | 70.45 | 7.37 | 8.86 | 72.14 | 6.86 | 9.01 |
SEM | 0.43 | 0.15 | 0.08 | 0.44 | 0.14 | 0.07 |
Means of 3 replications. All analyses performed in duplicate.
Means in the same column with different letters are significantly different (
SEM = standard error of the mean.
For all samples, Hunter b values decreased significantly between day 0 and day 14, but not thereafter. These results agree with Beggs et al. (
Lipid oxidation results are shown in Figure
TBARS values of deli-style turkey breast during storage under retail display lights at 3°C. Error bars represent ± SEM (=0.06). Means of 3 replications. All analyses performed in duplicate. SEM = standard error of the mean; TBARS, thiobarbituric acid-reactive substances; CON = control; 0.25CF = 0.25% citrus fiber; 0.50CF = 0.50% citrus fiber; PHO = sodium tripolyphosphate.
Sensory evaluation scores of deli-style turkey breast. Treatments with different letters differ significantly (
TPA results are shown in Table
Means for effect of treatment on instrumental texture of cooked deli-style turkey
Treatment | Hardness (N) | Resilience (%) | Cohesiveness | Springiness (%) | Chewiness (N mm) |
---|---|---|---|---|---|
54.58 | 28.76 | 0.62 | 77.78 | 26.69 | |
50.71 | 27.13 | 0.59 | 74.86 | 23.18 | |
56.02 | 26.29 | 0.59 | 75.89 | 25.59 | |
57.57 | 29.69 | 0.62 | 77.07 | 28.35 | |
2.94 | 0.72 | 0.01 | 1.36 | 1.91 |
Means of 3 replications. All analyses performed in duplicate.
Means in the same column with different letters are significantly different (
0.25CF = 0.25% citrus fiber; 0.50CF = 0.50% citrus fiber; PHO = sodium tripolyphosphate; SEM = standard error of the mean.
Sensory results are shown in Figure
The CON, citrus fiber treatments (0.25CF, 0.50CF), and phosphate treatment (PHO) all maintained equivalent quality throughout the 84-d storage period. It must be noted, however, that the phosphate level used in this study (0.105% of total product) was generally lower than in many commercial products and that higher phosphate levels would be expected to result in improved quality compared with a no-phosphate control. Although citrus fiber has been demonstrated to provide numerous benefits in various meat applications (
The authors thank Christine A. Fedler, Elaine M. Larson, and the staff of the Iowa State University Meat Laboratory for their technical assistance.