Effect of Sodium Potassium Phosphate (Carnal 2110) on

Chapter 15

Downloaded by UNIV OF MISSOURI COLUMBIA on January 6, 2018 | http://pubs.acs.org Publication Date: July 1, 1997 | doi: 10.1021/bk-1997-0674.ch015

Effect of Sodium Potassium Phosphate (Carnal 2110) on Acceptability and Color of Hot Smoked White Sturgeon (Acipenser transmontanus) 1

Frank A. Chapman, Susan L. Lucas, and Sean F. O'Keefe

Departments of Food Science and Human Nutrition and Fisheries and Aquatic Sciences, University of Florida, Gainesville, FL 32611-0370 The purpose of this investigation was to determine the effect of phosphate (sodium/potassium phosphate, Carnal 2110) on the chemical, physical and sensory properties of hot smoked White sturgeon (Acipenser transmontanus). White sturgeon were obtainedfroma commercial aquafarm and were shipped overnight on ice immediately after slaughter. Fish were filleted and were brined at 20°C with either 20% (w/v) NaCl or 20% (w/v) NaCl + 10% (w/v) Carnal 2110. Fish were hot smoked in a commercial Koch smokehouse. Target final water phase salt content was 2.5% w/w and heating was maintained at the fillet center at ≥63°C monitored by thermocouple for ≥30 min. Weight recovery (yield), color (L,a,b), and sensory acceptability panel testing were measured on freshly smoked fish. Phosphate greatly improved color development and improved slightly the acceptability and yield of the fish.

Sturgeon stocks worldwide were depleted in the late 19th and early 20th centuries due to over-fishing and habitat destruction. The large caviar fishery in the Caspian Sea has been largely stabilized by an extensive hatchery program in Russia (7). In the past 15 years, there has been increased interest in sturgeon due to developments in white sturgeon {Acipenser transmontanus) aquaculture (2). The white sturgeon is now commercially grown worldwide and is a source of caviar and sturgeon meat. The wholesale price of sturgeon meat (skinless, boneless) is currently about US $1 l-$15/kg and for caviar is >$500/kg. Sturgeon clearly represent an unusually attractive species for food fish aquaculture. Traditionally sturgeon meat is smoked and smoking increases the value of the meat considerably. Thus, smoking can be considered a value added process. Smoking can be divided into two main types depending on the temperatures the fish are exposed

'Corresponding author

166

© 1997 American Chemical Society Shahidi and Cadwallader; Flavor and Lipid Chemistry of Seafoods ACS Symposium Series; American Chemical Society: Washington, DC, 1997.

15.

CHAPMAN ET AL.

Effects of Phosphate on Smoked White Sturgeon

167

to during smoking: hot and cold smoking. Hot smoking requires a temperature of at least 63°C for 30 min to ensure destruction of pathogens such as Listeria monocytogenes. However, 30 min is too short to result in good color and smoke flavor development. Smoking is therefore conducted until an acceptable color and flavor are formed. Any process that increases the rate of color and flavor development while maintaining qualiy will have a strong impact on the economics of smoking.


Phosphates in Seafood Processing Phosphates have been used extensively for fish and seafood processing for many years (3,4). Phosphates allow processors to maintain quality in frozen and fresh seafood by preventing or decreasing drip loss (water loss) on freeze-thaw, prevention of oxidation and struvite formation (5). Phosphates are used extensively in frozen shrimp where they facilitate mechanical peeling, promote maintenance of weight duringfrozenstorage, and improve acceptability and shelf life. Thus, phosphates have been a very important aid to maintain seafood quality. However, there is little information available on the role of phosphates in smoked fish. Phosphates can be divided into categories depending on the polymerization of the phosphates in the molecules (4,5). The most commonly used phosphates in seafood processing are the condensed phosphates, sodium tripoly- and hexameta- phosphates (5). Sodium tripolyphosphate (STPP) has been used to control fish shrinkage in hot smoked fish. Addition of 2% (w/v) STPP to concentrated brine resulted in improved yields in halibut, silver salmon and black cod (6). The weight loss in halibut was reduced from 29.5 to 24.8%, in silver salmon from 28.7 to 25.2% and black cod from 25.6 to 24.0% after smoking at 21°C for 14 h then at 113°C for 1 h (6). Other than this report, there is little information available in the literature on the role of phosphates in hot smoked fish. The solubility of Na/Kphosphates in concentrated brines is much better than for STPP (data not shown). For this reason, Na/Kphosphate blends such as Carnal 2110 would be easier to use in commercial practice than STPP, by allowing more flexibility in brine concentration and temperature. The purpose of this study was to investigate the effect of Carnal 2110 on color development, acceptability, and recovery (yield) in hot smoked white sturgeon. Experimental Procedures Chemicals. All chemicals were obtained from Fisher Scientific and were reagent grade. Sodium tripolyphosphate was obtained from Rhone Poulenc (Atlanta, GA) and Budenheim's sodium/potassium phosphate (Carnal 2110) from Gallard-Schlesinger Industries Inc. (Carle Place, NY). Fish. White sturgeon (Acipenser transmontamis) were obtained from Stolt Sea Farm Inc. (Seattle, WA) on three separate occasions. Each shipment consisted of 2 bullets (deheaded, detailed, definned, gutted) which were evenly matched in weight (bullets weighted between 3-4 kg). The fish were obtained within 3 days of slaughter and were maintained on ice. The bullets were skinned andfilleted,stored in plastic zip-lock bags and held on ice until smoking. Fillets were cut and trimmed to remove all cartilaginous bone. The lateral fat layer was not removed (not deep skinned).

Shahidi and Cadwallader; Flavor and Lipid Chemistry of Seafoods ACS Symposium Series; American Chemical Society: Washington, DC, 1997.

168

FLAVOR AND LIPID CHEMISTRY OF SEAFOODS


Fish were smoked within 4-6 days of slaughter. The right and left fillets from each fish were subjected to the two brining treatments using the right fillet of one fish and the left fillet of the other fish were controls, and the corresponding fillets were treatments. Smoking. A Koch commercial smokehouse was used with dimensions l m x l m x 1.5 m (height). The smoke generator was used with hickory sawdust (Koch, Kansas City, MO) and smoke was transferred to the smoking chamber using a blower. Temperature was controlled at 75°C using a thermocouple with feedback to the heater. Brines were made of the following concentrations. Control brine was 20% (w/v) NaCl (no iodine, Publix, FL) and treatment was 20% (w/v) NaCl with 10% (w/v) Carnal 2110. The treatment brine was made by dissolving the phosphate first and the NaCl afterwards, since this increased the speed of dissolution. Fillets were cut into thirds by length (front, middle, back). Fillets were brined in control or treatment brines for 45 min at 20°C with mixing at 5 min intervals. The ratio offishto brine was about 0.3 kg/L. After brining, the fish were removed and were placed on screened racks (1.5 cm screen size) for drying at ambient temperature (25-30 °C) for 1 h. After drying, the fish were placed in the smokehouse which had been preheated to operating temperature. Fish were smoked for 3 h at a smokehouse temperature of 75 °C. Fish were removed, weighed and placed in plastic bags overnight on ice in a cold store (5 °C) before analysis. Analyses Sodium content Sodium was measured using a Ross Sodium electrode model 86-11 (Orion Research, Boston MA). Fish was chopped and a composite sample (10 g) was blended (Waring commercial blendor model 33BL79) with 100 ml distilled deionized (2D) water for 2 min. The blended samples were transferred to a 200 ml volumetric flask and the blender rinsed with ca. 80 ml 2D water and the rinsing added to the volumetric flask. Theflaskwas brought to volume. The instrument was calibrated and sodium concentration determined (ppm) as described in the electrode manual. Data were converted to water phase sodium chloride (% w/w) using the moisture content and atomic/molecular weights of Na and NaCl. Color evaluation. Color of smoked fillets was measured using the Lab scale with a CR-200 Chroma Meter (Minolta, Japan). Averages of 10 spot readings per section were obtained and the lightness (L), red-green (a) and yellow-blue (b) scores were averaged. Moisture (24.003) and ash (31.012) were measured using A O A C Methods (7). Analytical measurements were replicated. For each treatment, fillets were identified as front (F), middle (M), or back (B) portions. Only front and middle pieces were analyzed since the back pieces were thinner and narrower than the others and this affected rate of moisture loss and salt penetration in preliminary experiments. Each portion was evenly quartered, and each quarter was split into three layers, top (T), middle (M) and bottom (B). The bottom was the skin side of the fillet. Two of the quarters (diagonals) were analyzed separately in duplicate. Data for different sections were analysed separately and were pooled when there were no significant differences.



15. CHAPMAN ET AL.


169

Sensory analysis. Sensory evaluation was conducted using a likability test (Table I) as described by Larmond (8). Sensory evaluations were performed in the Food Science Sensory Laboratory at the University of Florida. Panelists were faculty, staff and student volunteers. The panel consisted of about equal numbers of men and women and ranged in age from 19-57 (median age 22). The sensory facility consisted of partitioned booths with running water, sinks and adjustable lighting. Front or middle sections were used for sensory analysis and each panelist received portions offishcut from the same position on thefilletsto avoid differences in location or thickness on acceptability. Fillets were cut into 1.5 cm cubes and panelists received 3 cubes per sample on white plastic plates along with an unsalted cracker and distilled water. Panelists were asked to taste the fish in the order presented (presentation was randomized and three digit coding used). Samples were kept on ice and served immediately when panelists arrived. Three sensory panels were conducted and the data were pooled then statistically analysed. Statistics. Analysis of variance was conducted using Statistica for Windows version 4.5 (Statsoft, Tulsa, OK) running on an I B M compatible personal computer (Zenon Inc., City of Industry, CA). Means were separated where main effects were significant using Tukey's Honest Significant Difference test at p0.05). The effect of section was significant (p=0.007). Moisture was lowest on the skin side (bottom) and highest in the middle section. The moisture content was consistently slightly higher in the phosphate treated fish, but the variability resulted in a non-significant treatment effect even though recovery (which should closely parallel moisture) was affected by


170


Table I. Ballot for 9-point hedonic test INSTRUCTIONS Please evaluate one sample at a time working from the top to bottom. Proceed when you are ready. Please indicate age and sex category.


Male Female

Under 18

18-29

30-44

45-65

>65

FOR E A C H SAMPLE Take a bite of cracker and sip water to rinse your mouth. Taste the first sample and circle the number that best describes your opinion of the sample. Repeat for the second sample. Sample Code Dislike extremely 1

Neither like nor dislike 2

3

4

Like extremely

5

6

7

8

9

Sample Code Dislike extremely 1

Neither like nor dislike 2

3

4

Like extremely 5

6

7

8

9

Describe the reasons for your choice: Sample Code Sample Code



CHAPMAN ET AL.


Front

Middle

Back

• Control • Phosphate Figure 1.

Weight yield of smoked white sturgeon fillets .

Control

Phosphate

• Top • Middle • Bottom Figure 2. Moisture (% w/w) in smoked white sturgeon fillets .




• Top • Middle • Bottom Figure 3.

Water phase salt (% w/v) in smoked white sturgeon fillets .

80

Water Phase Salt (%) Figure 4.

Relationship between moisture and water phase salt in smoked white sturgeon.


15. CHAPMAN ET AL.


173


treatment. Weight loss was lower than reported for other fish species (6), probably a result of the differences in time-temperature of smoking. Barrett et al (6) smoked for 14 h at 21°C then 1 h at 113°C vs 4 h at 75°C in our experiments. Water phase salt Water phase salt (Figure 3) was significantly affected by piece (p=0.036), treatment (p=0.024) and section (p=0.000006). The interactive effects of treatment by section (p=0.045) and treatment by fish (p=0.0057) were significant. These interactions probably result from differences in fish thickness and surface smoothness. The potassium in the Carnal 2110 may have been involved in the decreased penetration of sodium into phosphate treated fish. Although the sodium levels were lower in phosphate treated fish (Figure 3), the differences were relatively minor, except for the bottom section. The relationship between water phase salt and moisture is illustrated in Figure 4. The negative correlation (-0.77) was significant (p

Effect of Sodium Potassium Phosphate (Carnal 2110) on

Recommend Documents