INTRODUCTION. The loss of moisture, shrinkage, associated with carcasses during the post-slaughter chilling, storing and distributing periods is of

Transcription

1 AZINATE COATINGS FOR CARCASSES* * R. L. WEST, C. R. LAZARUS, J. L. OBLINGER AND A. Z. PALMER University of Florida INTRODUCTION The loss of moisture, shrinkage, associated with carcasses during the post-slaughter chilling, storing and distributing periods is of paramount importance to the meats industry. The major concern is with weight loss and the resulting reduction in total carcass value. However, quality reduction, as well as increased trim losses, occur as shrink increases. Surface dessication and color deterioration are detrimental to shelf -life a.nd consumer acceptability. During the initial chilling period post-slaughter, shrink loss is controlled by regulation of the refrigeration. Fleming and Earle (1968) and Smith and Carpenter (1973) indicated that carcass shrinkage can be reduced by the maintenance of low temperature conditions accompanied by high relative humidity and minimal air circulation. However, the maintenance of moist carcass surfaces resulting from reduced air circulation would be expected to be conducive to microbial growth, especially if temperature fluctuations are encountered. Application of alginate coatings to meat products is not a new concept for shrinkage control. Algin, a component of seaweed, forms an edible gel or film upon the addition of a polyvalent ion, particularly calcium ions (Anonymous, 1973). The application of a Ca-alginate film onto the surface of a carcass or a cut would be expected to lower the loss of moisture fromthe meat tissues since moisture would be removed preferentially from the film. Following the dessication of the film, meat tissues would lose moisture. Previous reports have dealt with the application of a Ca-alginate film to beef cuts to be frozen (Berlin, 1957), chicken pieces (Mountney and Winter, 1961) and beef steaks and pork chops (Allen et -- al., 1963). The previous studies showed the alginate coating to be effective in reducing the shrinkage loss. Allen -- et al. (1963) reported an improvement in texture and juiciness for coated steaks and chops. However, Allen et -- al. (1963) also observed a bitter, off-flavor in coated samples which they attributed to the high concentration of the CaC12 solution (5M) used, and the length of immersion time required in this solution for formation of a firm gel. * Presented at the 28th Annual Reciprocal Meat Conference of the American Meat Science Association, * Appreciation is expressed to D. H. McKee Inc., Tampa, for allowing the authors to test the Flavor-Tex concept on fresh meats and for providing financial support.

2 The procedure f o r f i l m formation followed by e a r l y i n v e s t i g a t o r s was t h e coating of t h e product by submersion i n a s o l u t i o n of sodium a l g i n a t e followed by immersisn of t h e coated sample i n a s o l u t i o n of CaC12. The r e t e n t i o n time i n t h e CaC12 ranged from two t o s i x t y seconds. T h i s long r e t e n t i o n time i n t h e saturated CaC12 s o l u t i o n could lead t o b i t t e r, o f f - f l a v o r noted by A l l e n e t a l. (1963). -- Earle (1968) reported the develqment of a process f o r t h e Caa l g i n a t e coating of products wherein t h e r e t e n t i o n time i n t h e CaC12 s o l u t i o n w a s d r a s t i c a l l y reduced. He observed t h a t g e l l i n g time could be g r e a t l y reduced and t h e required concentration of CaC5 lowered by a d d i t i o n of an e d i b l e gum t o t h e calcium g e l l i n g b a t h. The addition o f t h i s thickening agent increased t h e v i s c o s i t y of t h e s o l u t i o n and allowed f o r t h e instantaneous formation of a strong f i l m without imparting a b i t t e r f l a v o r. I n addition, Earle (1968) noted t h a t t h e film can be broken down and removed w i t h water soluble calcium sequestering agents such a s polyphosphates. The process developed by Earle (1968)i s patented and marketed under t h e tradename Flavor-TexR. McCormick (1975) reviewed t h i s process and indicated t h a t it i s p r e s e n t l y being used f o r coating f i s h f i l l e t s, shrimp, onion r i n g s, mushrooms and various cold extruded products. The present r e p o r t concerns t h e application of t h e Flavor-Tex process t o f r e s h meat carcasses f o r t h e c o n t r o l of shrinkage. An extensive study of i t s a p p l i c a t i o n t o lamb carcasses, which has been reported elsewhere (Lazarus e t a l., 1975), w i l l be reviewed and preliminary s t u d i e s of t h e coating of beef and pork carcasses w i l l be discussed. EXPERIMENTAL FINDINGS Ninety lamb carcasses were subjected t o t h r e e shrinkage treatments immediately post -slaughter ( Lazarus e t a l., 1975 ) T h i r t y (30) carcasses were coated with Flavor-Tex, 30 carcasses were enshrouded with a polyvinyl chloride (WC) f i l m f o r t h e i n i t i a l 24 h r postmortem and t h e remaining 30 carcasses were l e f t a s c o n t r o l s. The WC film used had very low moisture-vapor transmission r a t e s.. The Flavor-Tex was applied by spraying w i t h a compressed a i r system. An aqueous s o l u t i o n sf sodium a l g i n a t e and maltodextran w a s applied first t o t h e carcass, followed by spraying w i t h an aqueous s o l u t i o n of CaC12 and carboxymethyl c e l l u l o s e. The Ca-alginate f i l m was formed instantaneously and became stronger a s t h e moisture was removed. The added f i l m weight was approximately 1.5% of t h e hot carcass weight. Since go'$ of t h e added weight i s water and a l l the added material i s edible, t h e o r i g i n a l hot carcass weight vas used t o c a l c u l a t e shrinkage loss.

3 293 A comparison of shrinkage values between t h e various treatments i s shown i n t a b l e 1. A t 1, 2, 3, 5 and 7 days postmortem, t h e carcasses coated with Ca-alginate and those wrapped f o r t h e f i r s t 24 h r postmortem with t h e WC f i l m had s i g n i f i c a n t l y ( P <.O5) lower shrinkage values than d i d t h e c o n t r o l carcasses. Those carcasses wrapped i n WC f i l m had t h e lowest shrinkage l o s s a t a l l time periods. Upon removal of t h i s f i l m on day 1, t h e carcass surfaces were extremely m o i s t h t d r i e d somewhat during t h e d u r a t i o n of t h e observation period. Table 1. Postmortem shrinkage ( 3 ) of lamb carcasses a s r e l a t e d t o shrinkage treatment Day postmortem Shrinkage treatment C a -Alginate 1.55bb Olb 4.81b WC wrap 1.20c 1.88C 2.49c 3.43c 4.19C abc Means 3n t h e same h o r i z o n t a l l i n e bearing d i f f e r e n t s u p e r s c r i p t s d i f f e r significantly (P <.OS). the the had Few Visual a p p r a i s a l of t h e carcasses indicated t h a t those wrapped i n WC f i l m had b r i g h t e r, more appealing surface f a t color than did c o n t r o l of a l g i n a t e coated carcasses. The a l g i n a t e coated carcasses a glossy appearance which diminished a s t h e f i l m was dehydrated. differences in lean color were noted. The e f f e c t s of shrinkage treatments on c h i l l r a t e were monitored by determining i n t e r n a l l e g temperatures f o r t h e i n i t i a l 24 h r periods. These d a t a a r e presented i n t a b l e 2. As expected, t h e WC wrapped carcasses had a s l i g h t l y slower c h i l l r a t e s i n c e moisture evaporation from carcass surfaces was r e t a r d e d. A t 6 hr postmortem, t h e WC wrapped carcasses had s i g n i f i c a n t l y higher ( P <.05) i n t e r n a l l e g temperatures than did t h e other groups. However, no ilifferences were observed a t 24 h r postmortem. Shrinkage treatment e f f e c t s on t o t a l aerobic microbial counts of carcasses are shown In t a b l e 3. The mean loglo v a l e s presented i n t a b l e 3 r e f l e c t t h e t o t a l counts obtained by swabbing a 6.45 cm2 a r e a. Incubation of t h e p l a t e s (Standard P l a t e Count Agar) was f o r 5 days a t 2OC. The fat-covered s i r l o i n a r e a and t h e lean covered b e l l y area (flank-breast Juncture) were swabbed i n i t i a l l y and again a t 2, 5 and 7 days postmortem.

4 294 I n t e r n a l leg temperature ( C ) during c h i l l i n g cycle of lamb carcasses Table 2. Time (hr) a 10.3a 4.la 6 24 Shrinkage treatment Ca-Alginate 38.2" 10.oa 4.4a WC wrap 38.ka 14.3b 5.oa ab Means on t h e same h o r i z o n t a l l i n e bearing d i f f e r e n t s u p e r s c r i p t s d i f f e r s i g n i f i c a n t l y ( P <.O5). 3. T o t a l aerobic microbial counts f o r s i r l o i n and b e l l y areas 3f lamb carcasses a t 0, 2, 5 and 7 days postmortema Table Day postmortem C ont rol *ad D 3.04b 3.47b 3.45b" 3.gou 3.84b 4.24b 4.4p Shrinkage treatment C a -Alginate Sirloin area 33.75" *75:,ap C 3.1iC B e l l y prea 3.90" 3 *99b 4.34b 4.46b PVC wrap c 3.82d 4 ~4~ 4.03O 4.Ogb 4.31p 4.01b a Mean loglo values per 6.45 cm2. bc Means on t h e same h o r i z o n t a l line bearing d i f f e r e n t s u p e r s c r i p t s d i f f e r s i g n i f i c a n t l y (P <.O5). Values f o r the s i r l o i n area ( t a b l e 3 ) i n d i c a t e t h a t by 2 days postmortem, t h e carcasses wrapped i n PVC f i l m had s i g n i f i c a n t l y higher microbial c m n t s (3.64 bacteria/6.45 cm2) t h a n d i d the control (3.04) o r a l g i n a t e coated carcasses (3.87). A t 5 and 7 days postmortem, t h e a l g i n a t e coated carcasses continued t o have s i g n i f i c a n t l y lower counts than t h e PVC wrapped carcasses. These d i f f e r e n c e s possibly r e f l e c t t h e r e l a t i o n s h i p of increased surface moisture t o increased microbial growth.

5 295 The lower microbial counts found f o r t h e Ca-alginate coated carcasses could also be r e l a t e d t o t h e i o n i c e f f e c t s of t h e chloride ions i n t h e film. I n t h e b e l l y area ( t a b l e 3 ), no d i f f e r e n c e s i n microbial counts were observed between t h e t h r e e treatments. A l l counts were higher i n t h i s area than i n s i r l o i n area and were attribuked t o increased crosscontamination i n t h i s area during t h e d a i l y handling f o r obtaining shrinkage d a t a Since A l l e t a 1 (1963) had reported adverse off -f lavors f o r a l g i n a t e coated steaks and chops, a n evaluation of t h e e f f e c t s of coating lamb carcass l e g s with calcium a l g i n a t e on sensory panel scores w a s conducted. Legs from six c o n t r o l and six calcium a l g i n a t e coated carcasses were removed following t h e conclusion of the shrinkage t r i a l ( 7 days postmortem) and paired l e g s were coated o r recoated with calcium a l g i n a t e o r l e f t f o r evaluation of t h e o r i g i n a l treatment. The coating of c o n t r o l l e g s and t h e recoating of a l g i n a t e coated l e g s was performed, s i n c e t h e f i l m had almost completely dehydrated by t h e end of 7 days. I n addition, t h e recoating doubled t h e film concentration f o r d e t e c t i o n of o f f - f l a v o r s and odors. P r i o r t o cooking, t h e coated l e g s could be distinguished from t h e c o n t r o l l e g s by t h e presence of t h e f i l m. This d i f f e r e n c e w a s e s p e c i a l l y evident f o r t h e l e g s coated 3r recoated following t h e shrinkage t r i a l. After cooking, no d i f f e r e n c e s i n appearances were evident because the calcium a l g i n a t e g e l d i s s i p a t e s upon h e a t i n g. Cooking l o s s percent and sensory panel scores a r e summarized i n t a b l e 4. Treatment groups were found not t o d i f f e r s i g n i f i c a n t l y f o r cooking l o s s o r f o r any of t h e sensory panel evaluations. A l l samples were r a t e d acceptable ( 5 o r above) i n flavor, j u i c i n e s s and o v e r a l l s a t i s f a c t i o n. No off-odors were recorded. Results similar t o those reported f o r lamb carcasses, have been obsekved in preliminary s t u d i e s with pork and beef carcasses. Although very small numbers ( 7 per treatment) a r e involved, d a t a presented i n t a b l e 5 f o r pork carcasses i n d i c a t e s t h a t alginate coated carcasses shrank less than uncoated c o n t r o l carcasses. Additionally, t h e skin of coated pork carcasses remains very p l i a b l e, even during extended storage times. This p l i a b i l i t y should a i d ease i n machine skinning and, therefore, increase y i e l d s. The alginate coating a l s o appears t o r e t a r d d i s c o l o r a t i o n of t h e s p l i t v e r t e b r a l column normally observed a f t e r s e v e r a l days postmortem. A preliminary comparison of percent shrink l o s s f o r c o n t r o l and Ca-alginate coated beef carcasses i s shown i n t a b l e 6. Up through 96 hours postmortem, t h e coated carcasses had approximately 0.6% l e s s shrinkage than the shrouded c o n t r o l carcasses. Microbial counts were similar f o r both treatment groups ( t a b l e 7 ).

6 Table 4. Cooking l o s s and t a s t e panel scores f o r c o n t r o l, coated and recoated lamb legs Factor Cooking loss (%) Flavor" Juici n e s s a Overall satisfactiona O f f -odorb Ca -alginate Ca -Alginate Ca-alginat e a * a Based on a n 8-point s c a l e i n which 8 = l i k e extremely and 1 = d i s l i k e extremely. Based on a 3-point s c a l e i n which 3 = d e f i n i t e off-odor detected and l=no d e t e c t a b l e off-odor. Table 5. Comparison of s h r i n k l o s s ($ ) of c o n t r o l and Ca-alginate coatedapork carcasses Preliminary d a t a b Factor shrinkage treatmentc Ca-alginate a N = 7 carcasses per treatment. A t 24 h r postmortem. C Average amount of Ca-alginate added was l.&$ of carcass weight.

7 297 Table 6. Comparison of shrink loss ( d ) o f c o n t r o l and Ca-alginate coated beef carcasses Time postmortem C ont r ol 24 2.o Shrinkage treatmentb Ca -alginate *9 a N = 22 carcasses per treatment. Average amount of Ca-alginate added was Table 2.9 kg per c a r c a s s, 7. Comparison o f microbial loads on c o n t r o l and Ca-alginate coated beef carcassesa - Day postmortem Shrinkage treatment Ca -alginate *@ go * a Mean loglo values per 6.45 cm2 from neck a r e a. I n addition t o t h e shrinkage advantage, coated carcasses do not have t o be shrouded. The removal of moisture f r o m t h e f i l m causes a t i g h t e n i n g of t h e f i l m which smooths t h e surface f a t. This t i g h t e n i n g i s not s u f f i c i e n t t o produce t h e same e f f e c t a s a shroud i n such a r e a s a s t h e cod and b r i s k e t, b u t does adequately smooth other a r e a s. One s e r i o u s problem associated with t h e a l g i n a t e coating f o r beef carcasses was t h a t t h e surface was not as white a s it was following shrouding. I n f a c t, a slight yellow f a t color was accentuated by coating. I n v e s t i g a t i o n s i n t o methods of circumventing t h i s problem a r e c u r r e n t l y underway.

8 ADDITIONAL CONSIDERATIONS The a p p l i c a t i o n of Flavor-Tex t o carcasses would be economically f e a s i b l e only i f t h e carcass weight saved ( o r added) i s s u f f i c i e n t t o overcome t h e c o s t s of ingredients and t h e i r a p p l i c a t i o n. Based on t h e average shrinkage d i f f e r e n c e between c o n t r o l and coated lamb carcasses (0.86%) shown i n t a b l e 1, t h e t o t a l weight saved f o r a 22.6 kg carcass would be kg (0.867% x 22.6 kg) A t a n average p r i c e of $2.18/kg, this weight savings would be $0.43 per carcass. Film ingredients a t t h e present time c o s t $0.35/kg a s applied t o t h e carcass. Using of carcass weight a s t h e average amount of f i l m added, t h e c o s t of ingredients f o r a 22.6 kg carcass would be $0.12. Therefore, a preliminary savings of $0.31 per carcass could be r e a l i z e d, excluding cost of labor, equipment and maintenance.. The labor, equipment and maintenance cost f o r applying Fhvor-Tex t o carcasses would depend on t h e degree of automation b u i l t i n t o the system. The spraying process could be fully automated using USDA approved s a n i t a r y spraying systems. Labor would be required only f o r mixing t h e s o l u t i o n s and monitoring t h e equipment. For a beef k i l l operation, t h e process would lower l a b o r requirements by eliminating t h e labor used f o r shrouding. P r i o r t o t h e commercial use of t h e Flavor-Tex process, USDA approval f o r i t s a p p l i c a t i o n t o f r e s h meat and l a b e l l i n g requirements a r e needed. Alginates a r e approved f o r use i n many food products and Flavor-Tex is approved f o r use on seafoods, onion r i n g s, mushrooms and various extruded products. The e f f e c t i v e n e s s of an immediate post-slaughter a p p l i c a t i o n o f a Ca-alginate coating t o lamb, pork and beef carcasses f o r t h e c o n t r o l of shrinkage has been t e s t e d under laboratory conditions. Coated lamb carcasses were shown t o have lower shrinkage values than uncoated carcasses through 7 days postmortem. Surface microbial growth on coated and c o n t r o l carcasses w a s similar, except in some instances where t h e coated carcasses had s i g n i f i c a n t l y lower (P <.05) counts. The a p p l i c a t i o n of t h e Ca-alginate f i l m did not a f f e c t carcass c h i l l r a t e o r p a l a t a b i l i t y of lamb l e g s. Preliminary d a t a f o r beef and pork carcasses i n d i c a t e s similar r e s u l t s. I n a d d i t i o n t o reduced s h r i n k loss, o t h e r advantages f o r t h e a p p l i cation of Ca-alginate films t o carcasses have been observed. Such f a c t o r s a s elimination of beef shrouding, l e s s bone d i s c o l o r a t i o n and increased p l i a b i l i t y of pork s k i n should be considered. The a p p l i c a t i o n of t h e film a l s o appears t o be econonically f e a s i b l e, based only on the reduction i n shrinkage.

9 299 Studies conducted under commercial conditions will dictate the usefulness of this concept. Information is needed concerning the quality attributes of Ca-alginate coated products after vacuum packaging and after processing. Ultimately, consumer acceptance of the coated products will be needed. LITERATLTRF: CITED Allen, L., A. I. Nelson, M. P. Steinberg and J. N. McGill. corn-carbohydrate food coatings. Food Technol. l7:lok Edible Anonymous Kelco Algin/hydrophilic derivatives of alginic acid for scientific water control. Kelco. Clark, New Jersey Berlin, A Calcium alginate films and their application for meats used for freezing. Mayasnaya Ind. S.S.S.R. 28, 44. Chem. Abstr. 5l,l7OOp. Earle, R. D Methods of preserving foods by coating same. U.S. Patent 3,395,024. Fleming, A. K. and R. L. Earle Cooling and freezing of lamb carcasses. 2. Weight loss during cooling. Food Technol. 22:lOO. Lazarus, C. R., R. L. West, J. L. Oblinger and A. Z. Palmer Techniques for control of lamb czrcass shrinkage. J. Anim. Sci. 40:176. (Abstr.). McCormick, R. D Edible coating isolates oxygen and moisture, controls structure-seals in flavor. Food Prod. Dev. 9:14. Mountney, G. J. and A. R. Winter The use of a calcium alginate film for coating cut-up poultry. Poultry Sci. 40:28. Smith, G. C. and Z. L. Carpenter Postmortem shrinkage of lamb carcasses. J. Anim. Sci. 36:862.

10 Don Kropf, Kansas S t a t e : Was t h e r e any unusual d r i p appearance a f t e r cooking? Was t h e r e any j e l l y - l i k e m t e r i a l i n t h e d r i p? heat. R. L. \!est: No, it completely breaks down when you s u b j e c t it t:, Ide d i d not n o t i c e any d i f f e r e n c e i n t h e ammnt of d r i p e i t h e r.. D H Kropf : F u r t h e r m r e, when t h i s d r i e s off somewhat i s t h e r e a rehydration p o s s i b l e under humid conditions? R. L. West: possible. I t ' s an i n t e r e s t i n g idea. I t h i n k it ti0ul.d be kje have not r e a l l y looked a t t h a t but it probably w m l d b e. D. H. Kropf: One f u r t h e r question, l e t us say a f t e r 24 hours, i s t h e r e any appearance that would be v i s i b l e f o r a r e t a i l cut? E. L. West: A f t e r 24 hours it r e a l l y depends on how much or what t h i c k n e s s of film you have added b u t in a r e t a i l c u t a f t e r 24 hours it?*70uldp o s s i b l y be n o t i c e a b l e but I t h i n k a f t e r something l i k e 4 t o 5 days, o r 3 t o 5 days t h e f i l m has dehydrated s o much that you v m l d not even know it jias on t h e r e. It does bond very i n t i m a t e l y t o t h e s u r f a c e except for a very f a t or o i l y s u r f a c e. Don Kinsman, Connecticut: Eioger, have you compared t h e a l g i n a t e coating with propylene g l y c o l which has been approved and used on pork carcasses and pork l o i n s? R. L. West: No, w e have not. J. D. Kemp: The t h i r d and f i n a l paper of t h i s s e s s i o n i s t o be given by D r. Tom Bidner. Tom i s a n a t i v e of I l l i m i s and received h i s B.S. t h e r e. He received h i s M.S and Ph.D. degrees from Michigan S t a t e H i s t o p i c i s "Forage-Finished Beef. ' I U n i v e r s i t y and i s now a t L.S.U..