Restructured Pork With Texture Variation

RESTRUCTUREI) FORK WITH TEXTURE VARIATION

N.G. MARRIOTT, S.K. PHELPS, C.A. COSTELLO and P.P. GRAHAM

Deparnnent of Food Science and Technology Virginia hlytechnic tnstitute and State University

Blacksburg, Virginia 24061

Acci@ed for Publication August 11, 1986

ABSTRACT

Muscles were excisedfrom the shoulders of U. S. No. I pork carcasses within Ih postmortem. Samples were flaked as; small (head opening = 3.otnm), medium (head opening = 6.Imm) and large (head opening = 9.9mm) with an Urschel Comitrol 3600. Samples were formulated with 1.0 NaCl and 0.2% sodium tripolphosphate rSTP), 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 JIavor. Objective measurements included h'unter Color values, shear force, percentage cooking loss and lliobarbituric Acid (TBA) values. Results suggested that large flaked particles contributed to improved color and reduced cooking loss. Particle size had no e$ect on muscle cut resemblance, overall appearance, juiciness and JIavor. Increased particire size was responsible for decreased tenderness, cohesiveness and TBA va Iues but increased connective tissue amount.

INTRODUCTION

Use of prerigor muscle as an ingredient and/or alternative to conventional processing of postrigor beef has been previously determined to be a viable concept. During the past decade, some meat scientists have expressed an interest in accelerated processing of muscle foods. This interest has been manifested through research in the areas of hot boning and restructuring. Henrickson (1981) has reported potential energy savings of up to 50% through hot-boning of beef before rigor onset. Marrim et al. (1980) have suggested accelerated processing of prerigor pork as an altcmative to conventional practices. Prerigor beef (Mar- riott et al. 1985) and pork (Marriott et al. 1983) have been incorporated in for- mulations for restructuring in our laboratories with no differences (p> 0.05) in tenderness and other taste attributes when compared to postrigor counterparts.

Journal of Food Quality 10 (1!)87) 425435. All Rights Reserved. OCopyrighr 1988 by Food & Nurririon Press, Inc., Wesrpon, Connecricur. 425

426 N.G. MARRIO'IT, S.K. PHELPS, C.A. COSTELM AND P.P. GRAHAM

Previous results have suggested that a disadvantage of comminuted and restructured products is their similarity to ground or sausage products instead of the texture of a steak or chop (Mandigo 1982). In a comparison of various comminution methods (slicing, flaking and grinding) Costello et af. (1981) found that flaking at 2.2 "C resulted in a leaner and brighter appearing product but the overall palatability was not affected. Durland et al. (1982) evaluated the effect of flake size on product characteristics of a postrigor muscle by using cutting sur- face openings between horizontal separators of 6.lmm, 13.Omm and 18.9mm with flake sizes designated as fine, medium and coarse, respectively. These workers reported that the medium and 50% medium-50% fine blends were rated most acceptable for textural appearance. No effect of particle size on sensory panel evaluation for flavor or juiciness was detected but increased particle size decreased tenderness, overall palatability and texture desirability.

A significant decrease in percentage cooking loss with reduced particle size was reported by Chesaey et af. (1978). Sensory evaluation revealed that products with a large particle size (12.7mm) were less cohesive than medium (6.9mm) and small (3.Omm), with no difference between the latter. Tenderness and juiciness scores were rated higher for a smaller flake size and decreased with increased particle size. When evaluated for overall acceptability, the small and medium particle sizes were rated higher than the large particle size. However, Popenhagen et af. (1973) and Chesney et af. (1978) reported that product for- mulations with more than one flake size were superior to blends of the same size flakes.

Huffman (1982) and Breidenstein (1982) have suggested that further research is needed to determine the effects of various particle sizes and comminution methods on restructured meat products. Thus, this research was conducted to determine the effect of three different particle sizes on the acceptability of restructured chops manufactured from prerigor pork.

MATERIALS AND METHODS

Sample Preparation

The shoulders of U.S. No. 1 pork carcasses were removed and muscle boned within lh postmortem. The boneless samples were physically separated into portions that were visually leaner and fatter. All muscles of the shoulder (Picnic and Boston Butt) were incorporated into the leaner or fatter samples. The fatter portions were flaked using an Urschel Comitrol 3600 with a head opening size of 1.5mm. The lean portions were flaked as small (head opening = 3.Omm), medium (head opening = 6. lmm) and large (head opening = 9.9mm) using the same equipment. Each flake size was then formulated into a 4.54 kg batch con- taining 1.0% NaCl, and .25% sodium tripolyphosphate (STP) by mixing in a

RESTRUCTURED PORK 421

Hobart mixer (Model C-100) for 3 min. The mixed samples were then stuffed in- to 110 mm diameter casings. These samples were placed in a -20°C eaviron- ment until temperature equilibration and subsequently tempered at -4°C for 16h. The tempered logs were formed into the shape of boneless pork chops with a Ross Superform 720 Press adjusted to 37 kglsq.cm. pressure with 2 s dwell time.

These restructured samples were cut into 19 mm thick chops, wrapped in wax coated freezer paper, and stored at -20 "C until evaluated. Visual evaluations as described in the next paragraph were conducted on the frozen steaks at 5 and 56 days to simulate short and long storage periods between manufacture and con- sumption. Traits Measured

At 5 and 56 days after cutting and packaging, samples from all treatments were subjectively rated bj a 7-member rating panel with an average of 11 years of experience evaluating meat samples. Evaluations included color (8 = no discoloration; 1 = total discoloration); overall appearance (8 = very desirable; 1 = very undesirable); visual cohesiveness (8 = very cohesive; 1 = very noncohesive); muscle cut resemblance (8 = very high resemblance; 1 = no resemblance); juiciness (8 = extremely juicy; 1 = extremely dry); tenderness (8 = extremely tender; 1 == extremely tough); connective tissue amount (8 = none; 1 = abundant); and flavor intensity (8 = extremely intense; 1 = none). An example of descriptive nomenclature for each trait is 8 = very desirable; 7 = desirable; 6 = moderately desirable; 5 = slightly desirable; 4 = slightly undesirable; 3 = moderately undesirable; 2 = undesirable; 1 = very undesirable. Cohesiveness and muscle cut resemblance were determined by the ability of the particles to cling together and the similarity of the restructured chops to boneless cuts from the Longissirnus dorsi. Sensory evaluations at 5 and 56 days were conducted by a 10-member panel according to a scaling method by Larmond (1979). The panel members were given samples for instructions and coordination according to Rainey (1979) to ensure maximal accuracy and preci- sion. Samples that were evaluated for taste attributes were broiled for 5 min before turning and then caoked to an internal temperature of 70 "C as determined with cooperconstantan thermocouples and a Honeywell recording poten- tiometer (Model Y 153X62-P-(S)-16-IT-Ill-23-DJTA8K).

Representative samples from all treatments were objectively evaluated for col- or by using a Hunter Lab Model D25 Color Difference Meter with a 51 mm diameter aperature (illuminated area). Values for the Hunter Lab 45 0 tristimulus color standard No. C20-1651 were LL 91.7; aL -0.8; bL - 1.0. Ox- idative rancidity was nieasured by the Thiobarbituric Acid (TBA) Test (Tarladgis et al. 1960). Moisture, fat and salt content were measured by the official methods (AOAC 1080) and cooking losses were determined by calcula- tions of the prepared sample weights as a percentage of their uncooked weights.

428 N.G. MARRIOTT, S.K. PHELPS, C.A. COSTELLO AND P.P. GRAHAM

Cooked sample cores 12.7mm in diameter were obtained for determination of shear force by use of the Warner-Bratzler Shear device.

Sample AUocation

per treatment = 48 samples. Total sample size was: 3 flake sizes x 2 evaluation periods x 8 replications

samples Analyses

Statistical analyses included conventional analysis of variance (Ban et al. 1979; Snedecor and Cochran 1%7), and mean separation techniques described by Duncan (1955).

RESULTS AND DISCUSSION

Data in Table 1 reveal that restructured pork chops manufactured from large particles of lean prerigor pork sustained less discoloration (P C 0.05) after 56 days of frozen storage than samples made from fine and medium flaked muscle. The small and medium flaked samples did not differ from each other (P> 0.05) after 5 days of frozen storage, but, after 56 days the medium flaked pork restructured chops sustained less discoloration (P< 0.05) than those with small flakes. The higher scores (P < 0.05) for the chops with larger lean particles were at- tributed to the more obvious pigmentation from the larger chunks and less color degradation due to reduced heat build-up and less smearing from the production of larger flakes. The large flaked samples stored for 56 days were destroyed by a refrigeration malfunction. However, the data in this table reveal that frozen storage for 56 days had no effect (P > 0.05) on discoloration. These data suggest that restructured pork chops with larger lean particles will have superior color.

The Hunter ‘a’ values presented in Table 2 further suggest that restructured pork chops manufactured from prerigor pork with larger particle sizes have more red color (P< 0.05) after 56 days of frozen storage than those made from the small particles. Yet, these data reveal that the red color faded in both small and medium flaked chops and that no difference (P > 0.05) in the ‘a’ (redness) values existed after storage for 56 days. It appeared that the Hunter Color Dif- ference Meter was more sensitive in differentiating between the redness of those samples stored 5 and 56 days than the rating panel. This observation agrees with Lozano and Cassens (1984) but previous research in our laboratories (Marriott et al. 1985) has revealed that the rating panel is more sensitive to color changes than the Hunter Color Difference Meter. Although differences in ‘a’ values (P < 0.05) due to treatment were found, no differences (P > 0.05) in the lightness


TABLE 1. EFFECT OF PAKTICLE SIZE ON THE MEAN COLOR SCORES.

OF RESTRUCTURED FORK CHOPS

Days of Storage 5- -- T r e e tmen t

( P a r t T f l s L 5 6

Small

Medium

SE I SB !! -- 5 . gcd .16 4 . 1 d . I 1

6 . 2cd .16 6.3' .11

W e a n s are based on an 8-point scale (8=no discoloration; 1 =total discoloration) UMeans in the same row or ix~lumn with a common superscript are not different (P > 0.05)

('L' values) were detecttd and only minimal differences in 'b' values were observed. Nevertheless, this observation suggested that finer flaking and increased storage time are responsible for the degradation of the redness of restructured pork chops.

The rating panel for aplpearance traits consistently discriminated against the visual cohesiveness of remuctured chops with a larger particle size (Table 3). Those chops stored for 5 and 56 days which were manufactured from small flake sizes of lean exhibited more cohesiveness (P < 0.05) than the medium flaked samples which were more cohesive (P c 0.05) than those made with large flakes. The samples stored for 56 days were less cohesive (P C 0.05) than the chops with the same formulation which were stored only 5 days. This difference can be explained only by lmssible effects of dehydration and experimental variation. The major implication of these data is that increased particle size and storage time are responsilAe for decreased product cohesiveness.

Particle size of restructured chops and storage time had no effect (P > 0.05) on the resemblance of theire samples to whole muscle cuts (Table 4). The lack of differences is attributable to the fact that none of the samples closely resembled an intact muscle cut due to the variation of cohesiveness, texture and fat distribu- tion from a whole muscle cut. It appeared that particle size was only one factor responsible for resemblance of a whole muscle cut and will have a minimal effect on the resemblance cd restructured pork chops removed from a pork loin.

Data in Table 5 reveal that particle size and storage time had no effect (P > 0.05) on the overall appearance of the samples evaluated. Although these treatments affected color and cohesiveness, the total effect was not enough to make any difference in tht: overall appearance. Since these traits have only a par- tial effect on overall appearance, other characeristics (i.e. muscle cut

TABL

E 2.

EF

FECT

OF

PAR

TIC

LE S

IZE

ON

TH

E M

EAN

HU

NTE

R C

OLO

R V

ALU

ES O

F R

ESTR

UC

TUR

ED PORK

CH

OPS

Meas

urem

ent

Part

icle

Sir

e

- --

Sm

all

Medi

um

Lar

ge

Day8

Days

-

Days

~

--

5 56

5

56

5 56

-

-__

- X

SE

X --

- -

SE -

SE

x - -

- X

---

48.5'

.89

47.9'

.89

50.0'

.89

50.4'

6.3

.45

4.0'

.45

8.6'

.45

4.3

'

9.P

.24

9.Pb

.24

10.4'

.24

9.P

SE

-

X --

X

SE

--

SE

-

.89

47.8'

.89

----

- --

--

----

.45

8.4

' .4

5

----

9

.1'

.24

--

--

----

.2

4

~ ~

*Mea

ns

in th

e sa

me

row

with

a co

mm

on su

pers

crip

t are

not

diff

eren

t (P

> 0.

05)

RESTRUCTURED PORK 43 I

resemblance, fat distribcaion and texture) which were not different among treatments were responsitile for the lack of differences among the particle sizes and storage periods. Thes,: data suggest that variation in particle size and storage time from 5-56 days will not affect the overall appearance of restructured pork chops manufactured from pre-rigor pork.

TABLE 3. EFFECT OF PARTICLE SIZE ON THE MEAN COHESIVENESS SCORES.

CQ RESTRUCTURED PORK CHOPS

Treatment (Particle Size )

Small

Medium

Large

Dayeof Storage 5 6 - 5- -- -

E - rt - 6.2b .12 5.1' .12

5.0' .12 4 . P .12

2.4e * 12

SE SE

---- ----

'Means are based on an &point scale (8=very cohesive; 1 =very noncohesive) MMeans in the same row or column with a common superscript are not different (P > 0.05)

TABLE 4. EFFECT OF PARTICLE SL!E ON THE MEAN MUSCLE CUT RESEMBLANCE SCORES

OF RESTRUCTURED PORK CHOPSb

D z of S t o r a E ( P e r t l c l e l z e ) ---- 3 -- - -= --- Treatment

rr Small 5 . 3 .16 5.0 .17

Medium 5 . 4 .16 5 . 3 .17

Large 5 . 3 .16 ---- ----

'Means are based on an 8-point scale (8 =very high resemblance; 1 =no resemblance) bNone of the values are diflirent (P > 0.05)


TABLE 5 . EFFECT OF PARTICLE SIZE ON THE MEAN OVERALL APPEARANCE SCORESn

OF RESTRUCTURED BEEF STEAKS~

Tr en tmen t -- ( P a r t i c l e S i r e )

Smal I

Da 8 of S torage -+- __--_- w--- 2! SE 2!

5.3 .16 5.3

SE

.17

--

Medium 5.3 .16 5 . 7 .I7

.16 Large 5.2 .l6 ----

- ------- M e a n s are based on an 8-point scale (8=very desirable; 1 =very undesirable) bNone of the values are different (P > 0.05)

The effect of particle size and storage time on subjective measurements of sensory attributes is presented in Table 6. Juiciness was not affected (P> 0.05) by the flaked particle size. The major variation among treatments was only 0.7 of a rating. These data suggest that a variation in particle size will not affect product juiciness. However, restructured chops manufactured from large flaked particles were less tender (P c 0.05) and exhibited more connective tissue (PC 0.05) than those samples made from small and medium flake sizes which did not differ from each other (P > 0.05). This observation was predictable and logical since larger particles of postrigor muscle have been previously reported to have less desirable tenderness related attributes (Chesney et al. 1978; sideman et al. 1982). Although a less tender product could more closely resemble a whole muscle cut, the sensory panelists ratings for the samples with the larger particles suggested that these chops were objectionable.

Flavor was not affected (P > 0.05) by particle size. This observation is in agreement with other research conducted in our laboratories with restructured steaks manufactured from prerigor beef (Marriott et al. 1986). Restructured chops produced from coarse (large) flakes (data not shown) required more (P C 0.05) shear force than samples manufactured from small and medium flakes. This observation further supports the tenderness data in Table 6. Percentage cooking loss (data not shown) was higher (P < 0.05) for chops prepared from small flakes than for samples prepared from medium flakes. This observation does not agree with research by Chesney er al. (1978) who reported that smaller flakes yielded less cooking loss. Furthermore, the results published by Chesney er al. do not agree with the juiciness data of this study (Table 6). This discrepan- cy cannot be fully explained. These data suggest that particle size in the formulation will affect tenderness, connective tissue amount, shear force and cooking loss but will not influence juiciness or flavor.


TABLE 6. EFFECT OF PARTICLE SIZE ON THE TASTE ATTRIBUTES OF

RESTRUCTURED PORK CHOPS ~ - - ---------

__-- Taste Attrlbute Treatment ount o

(P-TZ-Fize) Juiciness' Tendernessb C onnzt ive T:sa~~e~ Of f-Plavord

Small 4.3e 6.1e 6.Ze 1.8e

Medium 4.8e 6.1e 6 . 0 e l.Be

Large 5.0e 3 . 9 1 3 . 3 f 1.4e

%leans are based on an 8-point scale (8=extremely juicy; 1 =extremely dry) bMcans are based on an 8-point scale (8 =extremely tender; 1 =extremely tough) W e a n s are bascd on an 8-point scale (8 =none; I =abundant) Weans are b a d on an 8-point scale (8=extremely intense; 1 =none) efMeans in the same column with a common superscript are not different (P > 0.05)

Storage time and particle size were responsible for higher TBA values (data not shown). However, after 5 days of frozen storage the large flaked samples ex- perienced more (P < 0.05) malonaldehyde formation than the chops with the small flakes which had higher (P C 0.05) mean TBA values (3.37) than those with the medium sized flakes (1.69). The chops manufactured from the large flakes yielded lower (P < 0.05) TBA values (0.87) than those from the other treatments. These data suggest that after storage for 56 days, those samples with the smaller flake sizes will sustain more oxidative rancidity.

CONCLUSIONS

Results from this research suggest that: (1) Restructured chops manufactured from larger flaked particles of prerigor

pork will have superior color, (P < 0.05) when measured objectively and subjectively.

(2) Increased particle size and storage time are responsible for decreased (P < 0.05) product cohesiveness.

(3) Particle size and storage time have no effect (P > 0.05) on muscle cut resemblance, overall appearance and juiciness and flavor.

(4) Increased particle size is responsible for decreased tenderness when measured objectively and subjectively, increased connective tissue amount, decreased cooking loss and lower TBA values.


ACKNOWLEDGMENT

The authors express their appreciation to the Virginia Agricultural Council for their support of this project, Ross Industries, Inc. for use of the Ross Superform 720 Press and Urschel Laboratories, Inc. for use of the Urschel Model 3600 Comitrol .

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MANDIGO, R. W. 1982.. Processing systems-mixing, temperature control and raw materials. In Proc. Internutionul Symposium Meat Sci. and Tech. pp. 223-227. National Live Stock and Meat Board, Chicago, Illinois.

MARRIOTT, N.G., POETKER, R.H., GARCIA, R.A. and LEE, D.R. 1980. Acceptability of acceltxated-processed pork. J. Food Prot. 43, 756-759.

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Restructured Pork With Texture Variation