Red claw crayfish (Cherax quadricarinatus), a tropical freshwater

Transcription

1 JFS E: Food Engineering and Physial Properties Influene of Gender and Spawning on Meat Quality of Australian Red Claw Crayfish (Cherax quadriarinatus) Stored at 2 C BAOHUA KONG, YOULING L. XIONG, CAODI FANG, KENNETH R. THOMPSON, LINDA S. METTS, LAURA A. MUZINIC, AND CARL D. WEBSTER ABSTRACT: Shell-ontailsofmale(M), nonspawningfemale(f), andspawningfemale(sf) Australianredlawrayfish (Cherax quadriarinatus)(n = 270) were aeroially stored at 2 C up to 10 d to monitor meat quality hanges under a retail ondition. Perentage protein of SF musle was higher (P < 0.05) and moisture and ash ontent lower (P < 0.05) than those of M and F musles. The ph of musle hanged during storage, with SF generally having a lower value than M or F(P < 0.05). Lipid oxidation inreased during the 1st 5 d and no signifiant differene existed etween the 3 musle groups. Cooking yield of SF (91.72%) at 10 d was signifiantly lower than that of M (96.25%) or F (97.81%), and its musle shear fore was also higher (P < 0.05) than M at 0, 3, 5, and 7 d and than F at 5 and 7 d. Sensory panel results (ooked meat tenderness, juiiness) were signifiantly orrelated with instrumental results (shear fore, ooking yield), with SF showing a lower meat tenderness, juiiness, and overall aeptaility than M and F samples. Keywords: gender, meat quality, red law rayfish, refrigerated storage, spawning Introdution Red law rayfish (Cherax quadriarinatus), a tropial freshwater rustaean speies so named for the striking reddish orange pathes on the laws of the adult males, is native to Australia ut is eing ommerially ultured in other parts of the world. Red law rayfish are similar to native Amerian rayfish in their general anatomy, reprodution, and feeding haits. However, red law rayfish differ from Amerian rayfish in that they have a larger potential size and higher perentage of dress-out (meat), an grow at temperatures ranging from 21 Cto32 C, and the females have multiple annual spawning and higher feundity (Jones 1989; Masser and Rouse 1997). In a hathery, mature female red law rayfish an spawn almost ontinuously throughout the year if onditions are suitale. Eah female will produe 100 to 1000 eggs per spawn depending on her size and general health (Masser and Rouse 1997; Jones 1998). There have een numerous studies on red law rayfish nutrient requirement (Figueiredo and Anderson 2003), diet formulation optimization (Muzini and others 2004; Thompson and others 2004), disease ontrol (Edgerton and others 2002), reprodution and hathing tehnology (Jerry and others 2005), and produtive harateristis (Nguyn and Austin 2004). In ontrast, there are limited data availale on red law meat quality, and the influene of gender and spawning ondition on the quality attriutes of rayfish musle is ompletely unknown. Meat quality as related to palataility is a omplex onept that is defined y a numer of parameters, inluding musle hemial MS Sumitted 2/27/2006, Aepted 5/30/2006. Author Kong is with the Dept. of Food Siene, Northeast Agriultural Univ., Harin , China. Authors Xiong and Fang are with the Dept. of Animal and Food Sienes, Univ. of Kentuky, Lexington, KY 40546, U.S.A. Authors Thompson, Metts, Muzini, and Wester are with the Aquaulture Researh Center, Kentuky State Univ., Frankfort, KY 40601, U.S.A. Diret inquiries to author Xiong ( ylxiong@uky.edu). Pulished as journal artile with the approval of the Diretor of Kentuky Agriultural Experiment Station. omposition, protein water-inding aility, musle shear fore, lipid oxidation, and flavor omponents. In a previous study onduted in our laoratory (Tseng and others 2002, 2003), quality hanges in red law tail stored at 0 C or sujeted to multiple freeze-thaw yles were investigated. The results showed that red law musle was somewhat resistant to protein denaturation and lipid oxidation at the refrigerated temperature, ut was suseptile to repeated freezing-thawing. Our more reent study demonstrated that dipping with antioxidant solutions effetively inhiited lipid oxidation and texture deterioration in red law stored in a 20 C freezer for up to 6 mo (Tseng and others 2005). The influene of spawning on musle protein quality of hake (Merluius husi Marini), although nonshellfish speies, has een studied. Pérez-Borla and others (2002) showed that autolyti ativity of musle extrats from prespawning hake was signifiantly higher than that of postspawning fish. Montehia and others (1997) found that fillets from prespawning hake stored at 20 C deteriorated more rapidly than postspawning hake in terms of loss of protein soluility. Beas and others (1991) reported that postspawning hake musle protein was more stale than prespawning hake musle protein. These reports seemed to suggest that the spawning status of red law rayfish ould also impat the quality of the rayfish meat quality during storage. The ojetive of the present study was to determine possile differenes in the musle quality of male, nonspawning female, and spawning female red law rayfish during refrigerated storage (2 C). Musle ph, hemial omposition, lipid oxidation, ooking yield, shear fore, and sensory harateristis were analyzed in order to identify possile influene of gender and spawning on meat quality stored at the refrigerated temperature. Materials and Methods Materials Juvenile red law rayfish (6.3 ± 3.0 g stoking weight) were grown in 0.04-ha ponds at Kentuky State Univ. Aquaulture Researh E320 JOURNAL OF FOOD SCIENCE Vol. 71, Nr. 6, 2006 C 2006 Institute of Food Tehnologists doi: /j x Further reprodution without permission is prohiited

2 Center, Frankfort, Kentuky for 12 wk (June 2, 2005 to Septemer 22, 2005) to a mean live weight of 58.9 ± 3.6 g. They were fed a wheat/soyean-ased diet that ontained 76% whole wheat, 10% wheat midds, 10% full-fat soyean meal, 1% menhaden fish oil, and a mixture of ommon minerals and vitamins. A total of 270 red law rayfish [90 males (M), 90 nonspawning females (F), and 90 spawning females (SF)] were randomly olleted from a large sample pool of over 2000 live red law rayfish. SF red law rayfish, whih omprised 14% (average) of the total female population, were readily identified y the eggs adhered to the underside of the ephalothorax; F red law rayfish were identified y a pair of genital pores at the ase of the 3rd pair (ounting from the head) of walking legs; and M red law rayfish were reognized y a pair of small genital papillae (projetions) at the ase of the 5th pair of walking legs. After stunning y hilling in an ie slurry for 2 min, the ephalothorax were removed manually, and the tails (musle, plus exoskeleton) were plaed in ied oolers and shipped to the Univ. of Kentuky Food Protein Researh Laoratory within 2 to 3 h of harvest. TBARS(mg/kg) = (A 532 /W s )9.48 where A 532 was the asorane (532 nm) of the assay solution, W s was the meat sample weight (g), and 9.48 was a onstant derived from the dilution fator and the molar extintion oeffiient ( M 1 m 1 ) of the red, TBA reation produt. The assay was arried out with 3 musle samples, and eah sample was analyzed in tripliate. Cooking Seven shell-on tails were individually weighed and then ooked in oiling water (100 C) for exatly 2 min, hilled to room temperature (21 C) for 15 min, and weighed again. Cooking yield (%) was expressed as ooked shell-on weight divided y raw shell-on weight of red law rayfish then multiplying y 100. After ooking yield measurement, the meat from eah individual tail was sujeted to instrumental textural analysis and taste panel evaluation as desried elow. Storage and sample preparation Shell-on tails of red law rayfish were separately plaed in styrofoam trays (10 in eah), over-wrapped with a PVC film, and stored in a2 C walk-in ooler for 0, 1, 3, 5, 7, and 10 d. During storage, fluoresent lights in the ooler were kept on to simulate supermarket retail display. At the end of eah storage period, 3 tails from eah animal group were deshelled and the pooled musles were finely hopped y lending with a miro Waring lendor for proximate omposition, ph, and lipid peroxidation analysis. Also for eah storage time, 7 tails with shell on were ooked for ooking yield and musle shear fore measurements. On 0, 5, and 10 d of postmortem storage, an additional 10 red law rayfish were used for sensory panel evaluation. Proximate analysis The analysis was done with a minimum of 3 musle samples, and eah sample was analyzed in tripliate. Protein was measured y the omustion method using a Model FP2000 Protein Analyzer (Leo Corp., St Joseph, Mih., U.S.A.). A 6.25 nitrogen-to-protein onversion fator was used for the alulation. Moisture was determined y drying the sample in a 105 C oven to a onstant weight. Crude lipid was measured y petroleum ether extration in a Soxhlet apparatus (1043 Soxte System, HT-Teator, Fisher Sientifi Co., Fair Lawn, N.J., U.S.A.) for 2.5 h at 60 C. Ash ontent was measured as the residue after overnight heating of the samples in a 600 C muffle furnae (Fisher Sientifi Co.). ph An aliquot of 3 g of mined musle was dispersed in 30 ml of deionized distilled water with a low-foam homogenizer (Brinkman Instruments, In., Westury, N.Y., U.S.A.). The ph of the slurry was measured using an AB 15/15 + ph meter with a glass ph eletrode (Fisher Sientifi Co.). The ph was measured on 3 musle samples, and eah measurement was done in tripliate. Thioarituri aid-reative sustanes (TBARS) Lipid oxidation was evaluated y TBARS aording to Sinnhuer and Yu (1977) with slight modifiations as desried y Wang and Xiong (2005). After reation with TBA, the sample solution was mixed with hloroform (1:1 ratio, v/v), vortexed, and susequently entrifuged at 1800 g for 10 min. The TBARS value, expressed as mg of malonaldehyde/kg of musle sample, was alulated using the following equation: Instrumental textural analysis Eah of the 7 ooked, deshelled, red law rayfish tails was weighed efore eing sujeted to individual textural analysis. A Model 4301 Instron Universal Testing Instrument (Instron Corp., Canton, Mass., U.S.A.) with a Warner-Bratzler shearing devie attahed to the load ell (1000 N apaity) was used to measure the musle shear fore. The tail was plaed in a transverse position to the lade so that the lade would ut through the 1st major musle segment from the anterior of the ooked tail aross the musle fiers (Tseng and others 2005). The ross-head speed of the Instron was 20 mm/min, and the 1st major peak (usually the highest, whih represented the maximal shear fore required to ut the musle sample) was reorded. Shear fore values (N) for individual red law rayfish were normalized ased on the weight (g) of the tails, and expressed as fore per sample unit weight (N/g) to eliminate size effets (Srinivasan and others 1997). Sensory evaluation Sensory evaluation of ooked red law rayfish (10 for eah storage time) was onduted y an 8-memer taste panel that onsisted of seleted faulty, staff, and graduate students who had prior experiene with musle food sensory tests. An Institutional Review Board (IRB) approval was otained for the sensory evaluation. The panel was trained in preliminary sessions to identify the speifi sensory traits of red law rayfish using 20 other ooked red law rayfish. A total of 3 panel sessions, orresponding to 0, 5, and 10 d of storage, were onduted. The sensory evaluation room ontained partitioned ooths eah illuminated with red lights. No visile sign of physial or psyhologial anomaly was oserved on any of the panelists during the sensory sessions, and the performane of eah panelist was onsidered satisfatory. Cooked tail meat was ut into approximately 1 m 3 its and mixed well efore serving. Samples (M, F, and SF) were randomized in all panel sessions. A warm-up sample (pooled meat from 5 to 7 red law rayfish) at the eginning of every panel session was evaluated as a reminder of the sore range for eah sensory trait. The following sensory harateristis were evaluated: loster flavor, offflavor, ranidity, tenderness, and juiiness. Sores were assigned on an evaluation sheet that was marked with a 7-point line sale: for loster flavor, 1 = mild, 7 = intense; for off-odor, 1 = nondetetale, 7 = intense; for ranidity, 1 = nondetetale, 7 = intense; for tenderness, 1 = tough, 7 = tender; and for juiiness, 1 = dry, 7 = juiy. Panelists marked on the sale (numered 1 to 7) where they felt est desried the sensory attriutes. As onsumers, panelists were URLs and addresses are ative links at Vol. 71, Nr. 6, 2006 JOURNAL OF FOOD SCIENCE E321

3 also asked for their opinion on aeptaility of the red law rayfish samples evaluated, that is, overall aeptaility with 1 = low and 7 = high. Statistial analysis Data were analyzed using the General Linear Models proedure of the Statistix 7.0 software pakage (Analytial Software, St Paul, Minn., U.S.A.) for miroomputers. Analysis of variane (AOV) was done to determine the signifiane of the main effets (gender, spawning, storage time). Signifiant differenes (P < 0.05) etween means were identified using least signifiant differene proedures. Regression analysis was run to determine possile orrelations etween instrumental and sensory panel results. Results and Disussion Proximate analysis The tail weight of M red law rayfish was slightly greater (P < 0.05) than that of F ut was similar to that of SF (Tale 1). There were no signifiant differenes in the perentage moisture, protein, lipid, and ash etween M and F musles. The results were in agreement with those reported y Thompson and others (2004). The perentage protein of SF musle was higher (P < 0.05), ut its moisture and ash ontent was lower (P < 0.05), than those of M and F. The higher protein ontent in SF musle may e due to the nutritional need for spawning; and the lower ash ontent maye due to some mineral transfer to the spawn during the period of spawning. Musle lipid ontent was quite low (< 0.18% on a wet weight) for all 3 rayfish groups. ph hanges The ph values of tail musle samples analyzed on different postmortem storage times are displayed in Figure 1. The ph initially dropped (to a minimum in 3 to 5 d) followed y an inrease during susequent storage, a pattern that was similar for all 3 rayfish groups. However, the M and F musles had signifiantly higher ph than SF during the 1st 3 d, ut on days 5 and 7, F musle had a higher ph than M and SF (P < 0.05). Overall, spawning lowered the musle ph, and the differene etween F and SF surpassed that existing etween M and F. The ph level in rustaean musle is normally higher than that of fish and mammalian speies eause the former had a higher ontent of nonprotein nitrogenous ompounds (Shahidi 1994). Gonçalves and others (2003) studied quality hanges of deepwater pink shrimp (Parapenaeus longirostris) and showed that the initial ph value of the pink shrimp was around 7.1, and the ph inreased during storage. Tale Proximate analysis of the tail musle of male, female, and spawning female red law rayfish Spawning female Shell-on tail weight (g) a ± ± ± 0.57 Wet musle asis Moisture (%) ± ± ± 0.10 Protein (%) ± ± ± 0.02 Lipid (%) 0.13 ± ± ± 0.01 Ash (%) 1.14 ± ± ± 0.02 Dry matter asis Protein (%) ± ± ± 0.08 Lipid (%) 0.70 ± ± ± 0.02 Ash (%) 6.01 ± ± ± 0.12 a The weight represented the mean ± standard deviation of 40 tails., Means in the same row with different supersript letters differ signifiantly (P < 0.05). ph A B A B C A Bd Cd A Cd ABa Figure Influene of gender and spawning on the ph values of raw red law rayfish musle stored at 2 C for various periods. Eah data point represents the mean of 3 repliations. Means in the same rayfish group (line) with different lowerase letters (a to d) differ signifiantly (P < 0.05); means etween rayfish groups on the same days with different upperase letters (A to C) differ signifiantly (P < 0.05). The death of an animal initiates major hanges in the iohemial onditions in the musle tissue. A ph deline immediately postmortem is generally asried to the aumulation of lati aid due to glyolysis, ut it is not lear why the red law rayfish musle ph ontinued to drop from day 1 to day 3 or day 5. Nevertheless, the susequent ph inrease may have resulted from the formation of amine ompounds (for example, ammonia) from miroial and enzymati ativity (Finne 1982; Aerle and others 2001). Alternatively, Pierson and Fox (1976) suggested an altered ion-protein interation due to an inreased influx of K + as a possile ause for postmortem ph elevation. So far, there is no literature report on the ph hange in spawning rustaean or fish during refrigerated storage. The reasons that spawning female red law rayfish had a redued musle ph ould e due to ertain speial physiologial onditions and/or musle iohemial metaolisms that arose during spawning and ontinued after death. In our preliminary study, we noted slower postmortem protein degradation (autolysis) in refrigerated SF musle than in F or M musle (Kong and Xiong, unpulished data). The suppressed proteolysis (thus, a redued release of amine groups or ompounds) may e partially responsile for the lower ph of SF musle. Lipid oxidation Oxidation is a leading ause for quality deterioration during proessing and storage of musle foods. Quality losses in oxidized meat produts are generally haraterized y flavor deterioration, disoloration, destrution of nutrients, and possile formation of toxi ompounds. Sine lipid oxidation was impliated in textural deterioration in many fish speies (Shenouda 1980), it was monitored during storage in this study. When stored at refrigerated temperature, lipids in meat oxidize and unsaturated fatty aids form hydroperoxides that are susequently leaved to seondary reation produts (Frankel 1998). As shown in Figure 2, TBARS in all 3 rayfish groups inreased (P < 0.05) during the 1st 5 d and then dereased. The deline, whih has also een oserved in other studies, may e attriuted to the reation of malonaldehyde with proteins and other musle onstituents (Buttkus 1967; Park and others 2006). No differene in TBARS was oserved etween M and F and etween F and SF for any of the storage periods. Ba Ba E322 JOURNAL OF FOOD SCIENCE Vol. 71, Nr. 6, 2006 URLs and addresses are ative links at

4 These results were in onert with the findings on freshwater prawn presented y Reddy and others (1981). Tseng and others (2002) reported that TBARS in red law rayfish musle stored at 0 C inreased steadily from mg/kg on day 0 to mg/kg on day 14. The values were lower than those from the present study. The reason for the differene may e that in this study, red law rayfish were stored at a higher temperature (2 C instead of the more ritial 0 C) and the samples pakaged with a transparent PVC film were onstantly exposed to the fluoresent lights, rendering the samples more suseptile to lipid oxidation. Cooking yield Cooking yield of red law meat was affeted y gender and spawning and hanged during storage (P < 0.05) (Figure 3). In M and F, the ooking yields were 94.6% and 95.2% on 0 d, and inreased (P < 0.05) to 96.3% and 97.8% after 10 d. Throughout storage, the ooking yield TBARS (mg/kg) a a a Figure The TBARS levels in raw red law rayfish stored at 2 C for various periods. Eah data point represents the mean of 3 repliations. Means in the same rayfish group (line) with different lowerase letters (a to ) differ signifiantly (P < 0.05). No signifiant differene was found etween the 3 rayfish groups at any of the storage times. of F appeared to e higher than M, ut the apparent differene was nonsignifiant exept on day 3 and day 10. The ooking yield of SF was 96.0% on day 0 and 95.9% 1 d later, and then dereased quikly to 91.7% y day 10, whih was signifiantly lower than M and F (P < 0.05). The apaility of red law rayfish musle to retain moisture upon ooking is attriuted to water-inding y musle proteins and water-holding within the musle myofiril matrix (Van Lak 1999). Postmortem hanges in musle proteins, for example, leavage of peptide onds y endogenous proteases, would result in an inreased net harge of proteins, thus, a stronger protein-water interation. This may explain the improved ooking yield in M and F musle samples stored for more than 7 or 10 d. Warner-Bratzler shear fore Signifiant differenes existed etween M, F, and SF in their shear fore values during postmortem storage. SF musle had a higher shear fore than M musle at day 0 and than F musle at day 3, and the differene remained over muh of the storage time, that is, higher than M at 0, 3, 5, and 7 d, and higher than F at 5 and 7d(P < 0.05) (Figure 4). Moreover, while oth M and F showed some flutuations in the shear fore hange during storage, shear fore of SF musle ontinued to inrease through 5 d and then dereased through the latter half of the storage time. On day 10, the musle shear values for all the 3 groups were idential (P > 0.05). The higher shear fore of SF musle proaly resulted from a higher degree of protein aggregation impliated y the redued ooking yield. It was noted that the ph of SF musle was lower than the ph of M and F musles on most of the sampling days (Figure 1). With a musle ph loser to the isoeletri point of myosin (ph 5.1), SF protein would e more prone to hydrophoi aggregation upon ooking when ompared with M or F proteins. Another possile reason for the shear fore differene was that SF musle ontained less proteolyti ativity postmortem than M and F musle, whih was oserved in our preliminary study (Kong and Xiong, unpulished data). Therefore, SF red law rayfish musle would have a more intat, thus, tougher, musle struture. The shear fore hanges in the 3 rayfish groups an initial inrease followed y a susequent redution may e explained y 2 opposing effets, namely tissue-toughening due to protein denaturation and Cooking Yield (%) AB A A A A A Ba Cd Shear Fore (N/g) A A B Ba B Ba A A Figure Cooking yield of red law rayfish after storage at 2 C for various periods. Eah data point represents the mean of 7 repliations. Means in the same rayfish group (line) with different lowerase letters (a to d) differ signifiantly (P < 0.05); means etween rayfish groups on the same days with different upperase letters (A to C) differ signifiantly (P < 0.05). Figure Shear fore of ooked red law rayfish after storage at 2 C for various periods. Eah data point represents the mean of 7 repliations. Means in the same rayfish group (line) with different lowerase letters (a to ) differ signifiantly (P < 0.05); means etween rayfish groups on the same days with different upperase letters (A, B) differ signifiantly (P < 0.05). URLs and addresses are ative links at Vol. 71, Nr. 6, 2006 JOURNAL OF FOOD SCIENCE E323

5 tissue-softening due to proteolysis. At the prolonged storage stage, proteolysis would seem to e predominant and offset the ounteration of tissue-toughening fator (Tseng and others 2002). Sensory panel evaluation The sensory panel results of ooked red law rayfish meat are summarized in Tale 2. All 3 rayfish groups exhiited hanges in sensory harateristis during storage. The loster flavor was not affeted (P < 0.05) either y gender or y storage time, and the panel deteted essentially no ranidity in all samples even after 10 d. Yet, the panel identified a low-level off-flavor in all 3 rayfish groups, notaly toward the end the refrigerated storage. Tenderness did not show signifiant hanges during storage for M and F musles, ut dereased (P < 0.05) for SF after 5 d. Juiiness sores for M and F tended to e greater than that of SF, and the differene etween the 10-d samples was signifiant. The deterioration in some of the quality attriutes in SF musle during storage led the panel memers to onlude that the SF tail meat stored for 10 d at 2 C was less aeptale than M and F tail meat. Relationship etween meat quality fators When all the samples tested were pooled to perform regression analysis, the ph was found not to e orrelated (P > 0.05) with musle shear fore or with tenderness although it was weakly orrelated with ooking yield (r = 0.466, P < 0.05) and juiiness (r = 0.415, P < 0.10) (Tale 3). Beause oth ooking yield and juiiness are governed y protein-water interation, an inrease in musle ph whih would result in more net harges on protein would allow more water to e immoilized in meat through hydrogen onds. Cooking yield was not orrelated with shear fore (P > 0.05), and the lak of orrelation suggested that red law meat toughness was determined y fators other than the aility of protein or the myofiril matrix to ind water. When data from instrumental analyses were ompared with those from the sensory panel evaluation, signifiant relationships were noted etween shear fore and tenderness (r = 0.837, P < 0.01) Tale Sensory evaluation of ooked red law rayfish Sensory Spawning attriute a female Day 0 Loster flavor 4.25 ± ± ± 0.26 Off-flavor 1.25 ± 0.16 d 1.00 ± 0.00 d 1.13 ± 0.13 d Ranidity 1.13 ± ± ± 0.00 Tenderness 5.34 ± ± ± 0.31 Juiiness 5.06 ± ± ± 0.25 d Overall aeptaility 5.25 ± ± ± 0.38 Day 5 Loster flavor 3.91 ± ± ± 0.27 Off-flavor 1.36 ± 0.16 d 1.36 ± 0.16 d 1.18 ± 0.13 d Ranidity 1.09 ± ± ± 0.10 Tenderness 5.32 ± ± ± 0.26 Juiiness 4.86 ± 0.28 d 4.91 ± 0.37 d 4.32 ± 0.30 d Overall aeptaility 5.23 ± ± ± 0.14 Day 10 Loster flavor 3.93 ± ± ± 0.44 Off-flavor 1.71 ± ± ± 0.30 Ranidity 1.29 ± ± ± 0.14 Tenderness 5.14 ± ± ± 0.28 Juiiness 4.86 ± 0.34 d 4.79 ± 0.21 d 4.29 ± 0.29 d Overall aeptaility 4.79 ± ± 0.47 d 3.93 ± 0.35 d a Loster flavor = 1 (mild) to 7 (intense); off-flavor = 1 (nondetetale) to 7 (intense); ranidity = 1 (nondetetale) to 7 (intense); tenderness = 1 (tough) to 7 (tender); juiiness = 1 (dry) to 7 (juiy); overall aeptaility = 1 (low) to 7 (High). d Means in the same row with different supersripts differ signifiantly (P < 0.05). Tale Correlation oeffiients (r) among seleted quality fators of red law rayfish meat Cooking Shear Fator ph yield fore Tenderness Juiiness ph Cooking yield Shear fore Tenderness Juiiness --- P < P < and etween shear fore and juiiness (r = 0.679, P < 0.01). A weak orrelation was also oserved etween ooking yield and tenderness (r = 0.540, P < 0.05), and etween ooking yield and juiiness (r = 0.491, P < 0.05). Within the sensory analysis, tenderness was highly orrelated with juiiness (r = 0.801, P < 0.01). Thus, Warner-Bratzler shear fore ould e used to predit tenderness and juiiness of red law rayfish meat with reasonale auray. Correlation analysis within individual rayfish groups also showed signifiant relationships etween instrumental and panel results. For example, SF had a lower shear fore and a lower ooking yield than M and F, and these gender and spawning effets were held true also for tenderness and juiiness evaluated y the taste panel (data not shown). However, although the level of lipid oxidation produts (TBARS) inreased slightly during storage, no orresponding ranidity ould e deteted y the sensory panel. It ould e that the TBARS level in red law rayfish musle studied was elow the detetion threshold (3 mg/kg) as estalished y Sinnhuer and Yu (1958). Whether the small amount of unharateristi off-flavor deteted y the sensory panel was related to the small prodution of TBARS remains unlear. Conlusion Results from this study indiated that the spawning ondition of Australian red law rayfish influened meat quality during refrigerated storage. In general, spawning female red law rayfish had an inferior meat quality ompared to male and nonspawning female red law rayfish, that is, a redued ooking yield, a higher shear fore, and a lower sensory tenderness, juiiness, and overall aeptaility. Meat quality differenes etween male and nonspawning females tended to e inappreiale. The meat quality variations oserved etween the 3 rayfish groups were not signifiantly orrelated with the raw musle ph, ut tenderness and juiiness of ooked red law rayfish ould e reasonaly predited from the ooking yield and Warner-Bratzler shear fore. Despite the effet of spawning and gender, red law rayfish meat appeared to e stale during refrigerated storage in oth textural and flavor properties. Aknowledgments The authors thank Dr. James Moy for his advie on sensory and textural analysis of the red law meat. This researh was funded, in part, y a USDA 1890 Institution Capaity Building Grant nr , and y a USDA CSREES Grant nr Author Kong was on saatial leave whih was supported, in part, y a Studying Aroad Grant of the Northeast Agriultural Univ., China. Referenes Aerle ED, Forrest JC, Gerrard DE, Mills EW Conversion of musle to meat and development of meat quality. In: Priniples of meat siene, 4th ed. Duuque, Iowa: Kendall/Hunt Pulishing Company. p Beas VE, Wagner JR, Añón MC, Crupkin M Thermal denaturation in fish musle proteins during gelling: effet of spawning ondition. J Food Si 56: Buttkus H The reation of myosin with malonaldehyde. J Food Si 32: Edgerton BF, Evan LH, Stephens FJ, Overstreet RM Synopsis of freshwater rayfish diseases and ommensal organisms. Aquaulture 206: E324 JOURNAL OF FOOD SCIENCE Vol. 71, Nr. 6, 2006 URLs and addresses are ative links at

6 Figueiredo MSRB, Anderson AJ Ontogeneti hanges in digestive proteases and arohydrases from the Australian freshwater rayfish, redlaw Cherax quadriarinatus (Crustaea, Deapoda, Parastaidae). Aqua Res 34: Finne G Enzymati ammonia prodution in shrimp held on ie. In: Martin RE, Flik GJ, Heard CE, Ward DR, editors. Chemistry and iohemistry of marine food produts. Westport, Conn.: AVI Pulishing Co. In. p Frankel EN Lipid oxidation. Dundee, Sotland: The Oil Press. Gonçalves AC, López-Caallero ME, Nunes ML Quality hanges of deepwater pink shrimp (Parapenaeus longirostris) paked in modified atmosphere. J Food Si 68: Jerry DR, Jurvis IW, Piper LR, Dennis CA Seletion for faster growth in the freshwater rayfish Cherax destrutor. Aquaulture 247: Jones CM The iology and aquaulture potential of Cherax quadriarinatus. Final report sumitted y the Queensland Dept. of Primary Industries to the Reserve Bank of Australia Rural Credits Development projet nr QDPI/8860. Jones CM Redlaw rayfish. In: Hyde KW, editor. The new rural industries a handook for farmers and investor. Canerra, Australia: Rural Industries Researh and Development Corporation. p Masser MP, Rouse DB Australian red law rayfish. SRAC puliation nr 244. Montehia CL, Roula SI, Roldán H, Pérez-Borla O, Cruplin M Biohemial and physiohemial properties of atomyosin from frozen pre- and postspawned hake. J Food Si 62: Muzini LA, Thompson KR, Morris A, Wester CD, Rouse DB, Manomaitis L Partial and total replaement of fish meal with soyean meal and rewer s grains with yeast in pratial diets for Australian red law rayfish Cherax quadriarinatus. Aquaulture 230: Nguyn TTT, Austin CM Inheritane of moleular markers and sex in the Australian freshwater rayfish, Cherax destrutor lark. Aqua Res 35: Park D, Xiong YL, Alderton AL, Ooizumi T Biohemial hanges in myofirillar protein isolates exposed to three oxidizing systems. J Agri Food Chem 54: forthoming. Pérez-Borla O, Rours SI, Montehia CL, Rold H, Crupkin M Proteolyti ativity of musle in pre- and post-spawning hake (Merluius husi marini) after frozen storage. Leensmit Wissens Tehnol 35: Pierson CJ, Fox JD Effet of postmortem ageing time and temperature on ph, tenderness and solule ollagen frations in ovine longissimus musle. J Anim Si 43: Reddy SK, Nip WK, Tang CS Change in fatty aid and sensory quality of fresh water prawn (Marorahium rosenerii) stored under frozen onditions. J Food Si 46: Shahidi F Seafood proteins and preparation of protein onentrates. In: Shahidi F, Botta JR, editors. Seafoods: hemistry, proessing tehnology and quality. London: Blakie Aademi & Professional. p 3 9. Shenouda SYK Theories of protein denaturation during frozen storage of fish flesh. Adv Food Res 26: Sinnhuer RO, Yu TC Thioarituri aid method for the measurement of ranidity in fishery produts II. The quantitative determination of malonaldehyde. Food Tehnol 12:9 12. Sinnhuer RO, Yu TC The 2-thioarituri aid reation, an ojetive measure of the oxidative deterioration ourring in fats and oils. J Jpn Oil Chem So 25: Srinivasan S, Xiong YL, Blanhard SP, Tidwell JH Physiohemial hanges in prawns (Mahrorahium rosenergii) sujeted to multiple freeze-thaw yles. J Food Si 62: Thompson KR, Muzini LA, Yaney DH, Wester CD, Rouse DB, Xiong YL Growth, proessing measurements, tail meat yield, and tail meat proximate omposition of male and female Australian red law rayfish, Cherax quadriarinatus, stoked into earthen ponds. J Appl Aqua 16: Tseng YC, Xiong YL, Wester CD, Thompson KR, Muzini LA Quality hanges in Australian red law rayfish, Cherax quadriarinatus, storedat0 C. J Appl Aqua 12: Tseng YC, Xiong YL, Feng J, Ramirez-Suarez JC, Wester CD, Thompson KR, Muzini LA Quality hanges in Australian red law rayfish (Cherax quadriarinatus) sujeted to multiple freezing-thawing yles. J Food Quality 26: Tseng YC, Xiong YL, Wester CD The preservation of the quality of the musle in frozen Australian red law rayfish (Cherax quadriarinatus) y pre-storage antioxidant dipping treatments. Int J Food Si Tehnol 40: Van Lak RLJM The role of proteins in water-holding apaity of meat. In: Xiong YL, Ho CT, Shahidi F, editors. Quality attriutes of musle foods. New York: Kluwer Aademi/Plenum Pulishers. p Wang LL, Xiong YL Inhiition of lipid oxidation in ooked eef patties y hydrolyzed potato protein is related to its reduing and radial savenging aility. J Agri Food Chem 53: URLs and addresses are ative links at Vol. 71, Nr. 6, 2006 JOURNAL OF FOOD SCIENCE E325