'.I'fCT OF THE USE OF NATURAL OR of using either a natural pork casing or IF" CASINOS ON THE an artificial fibrous collagen casing on 5 f,cial OPTING AND SENSORY QUALITY the ripening and sensory quality of a dry SAUSAGE. mouldy dry fermented sausage. For this p study, a sausage of high comercial b a n c a l e s , m . a g u ile r a , j .a . interest in Spain known as «fuet» was l'Ra n - • JAIME •* — and ■ J.M,------PEIRO. selected, whose determinant characteristics are those of a small > Pp. AL 1 Ac c ió n Animal y Ciencia de los calibre, coarse and mouldy salami. C * * Facu1tad Veterinaria. rsidad de Zaragoza. SPAIN. MATERIALS AND METHODS Sausages were prepared by a local P r o d u c t i o n manufacturer according to usual SaySgUa,ity of raw fermented practice. Each sausage, averaging 340 g f>ararr|^es is influenced by a number of in weight, contained 70% lean pork, ribenieters which govern sausage 25% pork back fat, 2.3% salt, lactose attent"^ amon9 them especial (1.7 g), glucose (680 mg), black pepper reia^.,0n has been paid to temperature, (680 mg), white pepper (680 mg), ^leKVe humidity and air velocity nutmeg (250 mg), sodium glutamate n^r anc) Rodel, 1978; Baumgartner (340 mg), sodium ascorbate (170 mg), ’hflUen 98° ; hendoza et a1-F 1983). The posphates (680 mg), nitrate and nitrite ^ l )tvCe on ripening and sausage (85 mg), colouring (E-124, E -127) and Sq ^ of a variety of ingredients has starter culture (Pediococcus spp.). H ^ vmeat grinder. The resultant mixture was fc,Ceat>leei!?,tetlly shown t0 exert a Gr 'ty (r, nr'u^nce on dry sausage used for all analyses. r^iaet ^a90ni and Cantoni, 1984; M o istu re d e term in atio n . About 3 ThUsa ’ 1986; Lücke, 1986). g of sample were exactly weighed ’ we have studied the effect and held at 102 + 2°C for 19 hours;

8 2 5 after cooling the sample was weighed cross sections. Samples for rn,ci ^ again. Water content was expressed as copical observation were taken at the percentage of the difference end of sausage ripening. Five prn ^ between initial and final weight sections were cut from small PieceL' related to initial value. sausage with a microtome and sta Fat content was determined with hematoxiline-eosine. A L,flr using a Soxhlet method (ISO/R 1443). (Dialux 20 EB) microscope was Nonprotein nitrogen determi­ observing the stained sections p nation. Ten g of sample were photographs were taken using 3 ^ homogenised for 1 min in 35 ml (model FX-35A) camera. efe distilled water using an Ultra-Turrax Sensory analysis Sausages y ^ homogeniser. Seven ml 10% TCA were evaluated for 19 quality're* 0f added to the homogenate and, after sensory parameters at the en ^ maintaining the mixture 2 h at 4°C, it ripening by a panel of ^ $ was centrifuged for 20 min at lOOOxg. semi-trained members. A 9-point b $ The supernatant was filtered, was used, 9 denoted highest valu^ | evaporated and protein content each parameter evaluated determined by a Kjeldalh method denoted lowest value. Analyse5 5; (ISO/R 937). performed in three separate seS5jP of Free fatty acids (FFA) deter­ in each of them a different mination. Fat extraction was carried sensory parameters was eva Uent^ out with chloroform-methanol solvent First whole sausages were Pre ^1 (2:1 vol/vol). Then 25 ml were removed to panelists for valoration of eXl ^ and mixed with 25 ml 96% ethanol. The perception. Thereafter panelist5 ^ mixture was titrated with NaOH 0.1 N. luated 3 mm sausage slices f°r j|/ The acidity was calculated as oleic external perception and finally 51 $ acid (Pearson, 1976). slices, after removing the casing' ^ Microbiological analysis Three presented to each panel memP casing portions of 1 cm2 surface were mouth perception evaluation. taken from different areas of each whole sausage. Samples were RESULTS AND DISCUSSION ^ suspended in sterile physiological «Fuet» sausages were rlPene’ ^ solution and suitable dilutions were natural conditions (11-14°C; ' made before plating. Total superficial R.H.) for 30 days after a short P ^ mould and yeast counts were deter­ fermentation at 28°C for ^ ^ mined on Sabouraud Chloramphenicol (90% R.H.). Along the ^ # agar incubated at 20°C for 7 days. fermentation and ripening Per’ ^ After microculture on Sabouraud agar, following physical and cnj5t/ isolated moulds were identified by parameters were measured: ^ ^ microscopical observation techniques content, pH, free fatty acids 3(] according to Ramirez (1982). Yeasts protein nitrogen. Onjtioil were stained by Gram and Giemsa Figure 1 shows moisture e methods and observed microscopically. along sausage ripening for P° Light microscopy of sausage materials used. It appears

8 2 6 Figure 2 Changes of pH during ripening process. ( ■ natural casing, □ artificia l casing).

S s . - °agS ■ Evolution of Free Fatty Figure 4 - Changes of nonprotein ^¡0/10QeXf)ressecl as percent of oleic nitrogen fraction during sausage * natij ^ of fa t- alon9 ripening. ripening. (■ natural casing, □ artificial aî casing, □ artificia l casing). casing). L a^r9oe Cases moisture content water vapour as described by r^^ent an inr,P°rtant decrease, in Effenberger (1985). ,^ilar wit;h previous reports for Changes in pH along ripening for Bauausa9es (Rodel and Klettner, both types of sausage are shown in ^ l9 8 ^ m9artner et al., 1980; Lois et Figure 2. In agreement with most prior ’Hg Us ’ ^°n dependent on the type of research reports ( Baumgartner et al., % ' ln accordance with their 1980; Rodel and Klettner, 1980; ehtical permeabilities to Barranco et al„ 1985; Lois et al., 1987)

8 2 7 pH decreases dramatically within the previously reported by Palumbo first few days of fermentation while it Smith (1977), León and Míllán (,9 nfl is not modified or increases gradually and Lois et al. (1987), although throughout ripening. As evidenced by studies have been as yet rePortefgtJ the curves obtained, sausage stuffed in the effect of casing upon free natural casing reaches significantly acid content. ^ higher pH values from 5th day on, as Nonprotein nitrogen evoi^ ^ was already demonstrated to a lesser throughout ripening, generally scceP is as a measure of proteolytic reach extent by Rodel and Klettner (1980). 0« According to Grazia et al. (1985) depicted in Figure 4. As it cante(- this pH rise ought to be referred most observed no variation in this ParafTlpe likely to a decrease in lactic acid appears to be evident, at the same1 ^ content rather than to ammonia that no differences between cas ^ formation, and it is to be related to used are noticeable. This somed mould mycelia colonization of sausage surprising result is in disagree^. mass and casing. with those described by DiericK e . As shown in Figure 3 free fatty (1974), Bello et al. (1974), Leóne acid content increases considerably (1978) and Lois et al. (1987), a,th% along ripening in a more or less lineal increases reported by them are - )e small or even negl'9 fashion with no noticeable differences very U5* between both types of casing used. Relationship of this fact with tPe^ i General behaviour agrees with that in our sausage mixture ta' Table !.- Superficial mould and yeast counts and respective percentage over W microorganism number along ripening of sausages stuffed into either natuf a rtificia l casing.

Natural casing A rtificial casing

Moulds (Peniciinum) Yeasts Moulds (Pénicillium) Yeasty 7» Days No/cm2 % No/cm2 % No/cm2 % No/cm2

SO*“ 1 4.16x 102 47.05 1.64x102 18.54 2.37X102 0.65 1.80x104 494 5 2.22x1 Ü3 20.83 8.90x104 80.20 4.16x10s 50.29 4.10X105 574' 10 1.49x106 71.34 6.00x10s 20.09 1.05x106 42.59 1.40x10S 3Ü.S4 15 2.06x106 83.07 4.20x10s 16.95 1.72x106 59.67 1.16X106 1 $ 20 2.49x106 94.28 1.50x10s 5.72 2.28x106 73.43 8.20x10S

25 1.92X1Q6 92.16 1.30x10s 6.40 1.13x106 65.38 6.00X105

8 2 8 >0, Coccus starter culture is never- the end of ripening their number is ess not known, slightly higher in natural casing, f ^'croorganism identification and constituting a much larger percentage c°unt beer)v1n9 °n sausages along ripening has of total microorganisms present than PeeiJ"arr1ed out only in both casings in artificia l casing. Sj^Ce away from sausage content, Yeasts are by far more abundant in tlle intiluence °f the presence and artificial casing at the firs t day of or of Lactobacilli and Micrococci ripening, being their numbers always h9s ' ated Bacteria on sausage quality slightly higher than that of natural hvest.been already sufficiently casing until the end of ripening and, '9ated for this type of sausage. contrary to moulds, their percentage of Co^ able 1 presents data obtained on total microorganisms present is larger spp_j " of total moulds (Pénicillium than in natural casing. tota1 yeasts Posent in Although no available data have r'Deni and aptific ia l casings along been found in the literature to discuss are n9 °t respective sausages. Moulds our findings, it has been repeatedly Preserit to a little extent shown the importance of moulds after stuffing in both (Dragoni and Cantoni, 1984; Grazia et sMnsa,ate,y the)r' they increase thereafter al., 1986, Lücke, 1986) and yeasts artjf^ Urnber- This rise is more rapid in (Comi and Cantoni, 1980) on ripening of % ,a* casing, but counts from 10th dry sausage, modifiying positively its n behave in a sim ilar manner. At sensory quality.

micrographs of 5 Jim thick cross sections (outer zone) of «fuet» Opened for 30 days, stuffed in either (A) natural pork casing x 100, (B) rl< casing x 250 and (C) artificia l fibrous collagen casing x 100.

8 2 9 t(0) With a view to understand the close of another section of the same relationship established between shows how mycelia penetrate mould mycelia and sausage casing, disintegrate casing natural 11 micrographs of sausage cuts were Thicker artificial casing ^ ,D obtained, as are shown in Figure 5. collagen) (C) appears to j5 Thinner natural skin (A) seems to colonized by mycelia, although barr’er disappear as it is totally colonized by also supposed to constitute no - ^ mould mycelia. Further magnification for mycelia growth across itnef T«We 2 - Sensory panel scores on a 9-point scale for sausages stuffed into e natural or artifical casing ripened for 30 days; 9 denoted highest value f°r parameter evaluated and 1 denoted lowest value.

Sensory parameters Natural casing Artificial casing

Visual appearance 6.17 i 1,03a* 6 .3 7 1 1.50^ Mould cover 6.30 i 1.41a 8.22 10.73^ Resistance to pressure 8.00 i 0.71a 8 .1 9 i 0.5 m External smell: - Intensity 6 .0 9 i 0 . 8 2 a 2.5310.93^ - Quality 6.83 i 0.96a 5 .1 5 1 1-33Ca Overall external perception 6.28 ± 1.05a 6.10 1 1 06

Slice cut external perception Visual appearance 7.33 ± 0.98a 6 .9 0 1 1-09^ Total fat 5.03 + 1,35a 4 .7 5 1 1-39 Easiness of casing removing 2.87i 1.26a 8 .4 0 1 0.74 Smell: - Intensity 6 .7 5 l 1.17a 5 .8 9 1 1 33 - Quality 7.33 + 0.72a 6.83 1 1 ^ 9 Colour 7.20 + 0.65a 6 . 3 7 l ° 9 l Overall cut perception 7.03 l 0.74a 7 .1 0 i O - 87

Slice mouth perception Flavour: - Intensity 7.47 + 0.66a 7 .1 0 1 0 .8 ^ - Quality 7.53 10.66a 5 .9 7 1 1 ° 4 T oughness 6.78 i 0.70a 6 .2 8 1 !■' \ Juiciness 6.87 + 1.0 l a 6 .4 0 1 0 .0 1 c Overall mouth perception 7.41 i 0.45a 6 l 7 i O ^ C

Overall acceptability 7.50 1 0.68a 6.31 1 0 7 9

c^1 *Means within the same row not followed by the same letter are signifl different (b: p < 0.10, c: p < 0.01).

8 3 0 ^ r i a l into sausage filling. ACKNOWLEDGEMENTS Nevertheless, the closer rela- The authors wish to thank '°nship existing among mould, collaboration and advice of Dr. J.F w Ural casing and sausage is evident, González on microorganism ,ch appears to be consistent with identification and Drs, M. Gallego and '-hp higher pH reached in this sausage M.C. Arnal on cross sections ac c°rdinq to Grazia et al. (1986) microscopic observation. Table 2 shows results obtained in i thft sensory evaluation of both types of REFERENCES saus ~age. First to point out is the fact Barranco, A., Leon, F., Penedo, J.C., that -fuet» stuffed in natural casing is Beltran de Heredia, F, Mata, C., rat ecl at least sim ilar but in most Montero, E. & Martins, C. (1985): tu es with a higher quality scoring Modificaciones de la composición ^.an that stuffed in artificial skin, química y de las características de h the sole exception of easiness of estabilidad del chorizo durante el SjS'n9 removing ("peeling"), which is proceso de maduración en condiciones ^pficantiy higher in the latter, It naturales (a), Alimentaria 165:35-40. W 136 embbasized that Intensity and S, Mty °f smell and flavour are always Baumgartner, P.A., Klettner, P.G, & ,ficantly higher in natural «fuet», Rodel, W. (1980): a ^ eN as the overall mouth perception The influence of temperature on some °Verall acceptability scores. parameters for dry sausage during Sen c,,scussed before, this superior ripening. Meat Sci, 4:191 -201. ge SorV quality of «fuet» sausa- refpStUfred in natural casing is to be Bello, J., Larralde, J. & Saenz de fer2rrecl to a higher pH after the Buruaga, M.I. (1974): ripe entat i° n Phase reached along Estudio de las modificaciones Of due most likely to the effect proteicas que tienen lugar durante la lar9er colonization of natural curación de algunos derivados cárnicos. rw ^ by superficial moulds, A Curación del Chorizo tipo Pamplona. toijjJVe e^fect of high yeasts counts Anal. Bromatol. £6:105-210. a1so be taken into consideration. Bóhme, C.F. (1984) E l u s io n s Influence de la peau de saucísse sur la D0Ss6PrV fermented sausage «fuet» qualíté. Rev. Techn. Vet. Alim. Wher|Sses a superior sensory quality ZL( 12): 19-29. opp0 stuffeq into natural casing as CaSj to a rtific ia l fibrous collagen Comí, G. & Cantoni, C. (1980): to g 9,This f act appears to be related Flora blastomícetíca superficiale di r'Peni ^ er pH 0f the former along insaccatí crudi stagionati. Ind. Alim. Cqi0 n9> most probably due to a larger 19:857-860. s u c t i o n of natural casing tissue by lcia1 moulds. Díerick, N., Vandekerckhove, P. & Demeyer, D. (1974):

8 3 1 Changes in nonprotein nitrogen Lücke, F.K. (1986): compounds during sausage ripening. J. Microbiological processes in ^ Food Sei. 39:301-304 manufacture of dry sausage and ra ham. Fleischwirtschaft 66: 1505-1 Dragoni, 1. & Cantoni, C. (1984): Le muffe nei prodotti carnei. Mendoza, 5., Flores, J. & Silla> ^ Ristorazione collettiva 9(12):74-77. (1983): Influencia de la temperatura Effenberger, G. (1985): estufado sobre las caracterísüc Eigenschaften der Kunstdärme. mícrobiológicas y químicas del chofl Fleischerei 9:730-736. Rev. Agroquím. Tecnol. AlíMe 23:86-96. Grazia, L., Romano, P., Bagni, A., Roggiani, D. & Guglielmi, G. (1986): Palumbo, S.A. & Smith, J.L. (1977): ^ The role of moulds in the ripening Chemical and microbiological chanf! process of salami. Food Microbiol. during sausage fermentation , 3:19-25. ripening. In "Enzymes in food 3 , beverage processing" (Eds. R.L 0r^ aa| Klettner, P.G. & Rödel, W. (1978): A. J. Angelo). American CheM,c Überprüfung und Steuerung wichtiger Society. Parameter bei der Rohwurstreifung. Fleischwirtschaft 58:57-66. Pearson, D. (1976): j5 Técnicas de laboratorio para el anán León, F. & Millán, R. (1977): de alimentos. Acribia. Zaragoza. Cambios químicos durante la maduración del salchichón. 1: Ramírez, C. (1982): Alteraciones en la fracción lipídica. Manual and atlas of the Poníc* ^ Arch. Zootec. 2£>( 103X293-301. Elsevier Biomedical Press. Amstefd

Rödel, V.W. & Klettner, P.G. (1980): León, F. , Millán, R. & Serrano, A de5 Beitrag zum Einfluss (1978): die Cambios químicos durante la Hüllenmaterials auf maduración del salchichón. 3: Rohwurstreifung. Fleischerei Modificaciones experimentadas por los 1027-1030. compuestos nitrogenados solubles en agua. Arch. Zootec. 27( 106): 105-116.

Lois, A.L., Gutierrez, L.M., Zumalac^- rregui, J.M. & Lopez, A. (1987): Changes in several constituents during the ripening of "Chorizo" - a Spanish dry sausage. Meat Sci. J_9:169-177.

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