1,721,091 research outputs found
Rabbit meat processing and traceability
No full textRabbit meat is a highly digestible, tasty, low-calorie food, often recommended by nutritionists over other meats, yet it is still considered a niche product, especially because of its time consuming preparation which requires culinary skills and because of cultural differences among European consumers. For this reason, the processing industry in Europe is gradually improving the availability of rabbit meat in a large variety of processed ready-meals which make it easier to prepare thus meeting the demands of modern consumers. This shift towards further processed products in Europe will soon underscore the necessity for higher standards in rabbit meat in order to improve sensory characteristics and functional properties. Rabbit production and processing involve a series of interrelated steps and the quality of rabbit muscle as food depends upon chemical, physical, and structural changes that occur in the conversion of muscle to meat. During the production and management of rabbits, (preslaughter) factors not only exert important effects on muscle growth, composition, and development, but also determine the state of the animal at slaughter. Moreover, large rabbit industry integration is becoming more important and the development of rabbit meat production is forcing processing plants to improve slaughter capacities by using high-speed and more automated slaughter lines. From the point of view of food safety, these changes can lead to higher microbial risks due to the possible cross-contamination during preslaughter (crating, transportation, and holding conditions) and processing (skinning and evisceration) operations. Furthermore, European rabbit production has been influenced by the introduction of more restrictive regulations and higher consumer attention to food safety aspects. All this has come about as a consequence of the many meat safety crises of previous years which have convinced the European Union to enact several regulations aimed at guaranteeing meat safety and systems to prevent or at least manage similar future crises. From January 1st 2005 (Regulation 178/2002/EC), it will be compulsory for all feed and food operators to adopt a traceability system. The major objective is to enforce the provision of clear and reliable information to consumers at sales points, based on a system of being able to track meat back to the source animal, the slaughterhouse and the cutting unit of origin.
This paper is divided in two sections, the first provides an overview of the steps of rabbit processing and its influence on product quality, while the second focuses on the application of traceability to rabbit production
Color variation and characterization of broiler breast meat during processing in Italy
No full textThe variation in broiler breast meat color (L*a*b*) which normally occurs during processing was evaluated using a Minolta Chroma Meter on a total of 6,997 broiler breast fillets (P. major muscles) from a total of 79 different flocks. The samples were randomly collected at 3-6 h post-mortem from the deboning line at a single major Italian processing plant. In addition, a total of 216 fillets were selected based on lightness (L*) values as being dark (L*56) and analyzed for ultimate pH, intact and ground meat cooking loss and shear value. The overall range in measured lightness (L*) was considerable and varied from 40 (dark) to 66 (pale) indicating that high breast meat color variation during processing could exist. Broiler breast meat during summer was found to be paler (+1.7 L* unit), less red (-1.0 a* unit) and less yellow (-0.7 b* unit) than breast meat samples collected during the winter confirming that the incidence of pale meat is greater during summer as indicated by non-scientific observations of plant personnel. It was also determined that paler (L*>56) breast meat is associated with lower ultimate pH and poorer water holding capacity, while dark (L*<50) breast meat is associated with higher muscle pH and cooking yield
Variabilità del colore delle carni avicole e riflessi sulla qualità dei prodotti
No full textNegli ultimi tempi numerose ricerche condotte nel pollo e nel tacchino hanno messo in luce una diretta dipendenza fra la selezione di linee genetiche sempre più produttive per velocità di accrescimento, efficienza alimentare e sviluppo delle masse muscolari e la comparsa di alcune patologie e disfunzioni muscolari. In questi tipi genetici è stato infatti accertato un aumento dell’incidenza di miopatie (es. miopatia dell’Oregon), un aumento della dimensione del diametro cellulare medio ed una diminuzione del grado di “capillarizzazione” dei tessuti. Inoltre, a livello metabolico è stata osservata un’accentuazione del metabolismo glicolitico muscolare che ha favorito la comparsa, soprattutto in corrispondenza dei mesi estivi, di carni caratterizzate da bassi valori di pH ultimo, colorazione pallida e scarsa capacità di ritenzione idrica (WHC). Queste carni sono state definite da alcuni ricercatori con il termine (“PSE-like”) a causa delle similitudini riscontrate con le carni suine “anomale” di tipo PSE (Pallide, Soffici ed Essudative).
La WHC è ritenuta una delle più importanti caratteristiche qualitative delle carni, in quanto direttamente correlata con le rese di lavorazione, gli attributi sensoriali e la stabilità microbiologica dei prodotti. In particolare, le carni avicole PSE determinano la comparsa di maggiori problemi quando vengono impiegate per la preparazione di prodotti nella cui formulazione non vengano utilizzati additivi in grado di migliorarne la funzionalità proteica ed aumentarne la capacità di ritenzione idrica.
Numerosi autori hanno confermato l’esistenza di una stretta relazione tra il pH muscolare, il parametro colorimetrico L* (luminosità) e la capacità di ritenzione idrica (WHC) delle carni avicole. In ragione di ciò, la misurazione oggettiva del colore è stata proposta quale metodo rapido, poco costoso e di semplice rilevazione, per l’individuazione di differenti classi qualitative delle carni in funzione della loro capacità di ritenzione idrica. Da un nostro precedente studio è emerso tuttavia che l’efficacia del metodo è subordinato alla messa a punto, da parte di ciascuna filiera produttiva, di propri range di L* in funzione di fattori di allevamento e di processo in grado di influenzare il parametro considerato. La relazione tra colore e qualità dei prodotto finale è stato oggetto di una serie di ricerche al fine di: i) determinare la variabilità del colore delle carni di pollo in condizioni di lavorazione industriale; ii) caratterizzare, dal punto di vista tecnologico, carni dotate di colorazione differente (“scure”, “normali” e “pallide”); iii) stimare l’incidenza delle carni PSE di pollo sia in termini globali che in funzione della stagione (estate, autunno, inverno).
I risultati ottenuti mostrano che petti di pollo dotati di colorazione pallida sono associati ad un notevole peggioramento delle caratteristiche tecnologiche e in particolare alla capacità di ritenzione idrica. Dall’analisi dei dati colorimetrici rilevati su circa 7000 petti di pollo, prelevati nell’arco dell’anno in funzione di differenti fattori di allevamento e macellazione, è emersa una considerevole e significativa variabilità nel colore delle carni, come evidenziato dall’andamento dei parametri colorimetrici esaminati (L*, a*, b*). Queste osservazioni concordano con i risultati ottenuti in altre realtà produttive, anche molto diverse tra loro (Nord America e Regno Unito). L’esame della distribuzione della luminosità (L*) delle carni ha mostrato che questa tende ad aumentare passando dalla stagione invernale a quella estiva. L’applicazione del “valore-soglia” di luminosità (L*=56), stabilito per l’individuazione delle carni “pallide”, ha permesso di verificare che durante i mesi caldi si assiste ad un importante aumento dell’incidenza di petti di pollo con caratteristiche PSE (15,5% in estate, 5,5% in autunno e 2,7% in inverno)
A comparison of water distribution and protein oxidation between poultry and rabbit meat
Full text linkIn the last years, proton Nuclear Magnetic Resonance (NMR) relaxometry has been successfully applied to study water mobility and distribution in porcine meat. In addition, although neglected for decades, the impact of protein oxidation on meat quality traits has been recently reviewed. Within this context, considering the incomplete knowledge on water distribution and mobility in white meats and the lack of information concerning protein oxidation, this study aimed at provide reference values on poultry (chicken and turkey) and rabbit meat. For this purpose, rabbit (L. lumborum muscles from 11 weeks-old males slaughtered at 2.7 kg), chicken (P. major muscles from medium-size 44 days-old male broiler slaughtered at 3.0 kg) and turkey (P. major muscles from 20 weeks-old male birds slaughtered at 21 kg) meat samples (n=8/specie) were selected 24 h post-mortem and used to assess ultimate pH, colour (L*a*b*), NMR relaxation properties and protein oxidation. In detail, proton transverse relaxation (T2) decay curves were recorded, at the operating frequency of 20 MHz, with a Bruker (Milan, Italy) Minispec PC/20 spectrometer, while protein carbonylation was assessed following a novel 2,4-dinitrophenylhydrazine (DNPH)-based method. Overall, ultimate pH values and colour were consistent with previous studies. If compared to both chicken and turkey, rabbit meat exhibited a remarkably higher proportion of the extra-myofibrillar water fraction (2.4 and 2.8 vs. 8.4%; P<0.001) and a consequent decrease in the intra-myofibrillar one (93.7 and 93.3 vs. 88.5%; P<0.001). However, although increased, the extra-myofibrillar water in rabbits appeared to be more tightly bound (lower T2) in comparison to both chicken and turkey meat (130.3 vs. 286.3 and 210.6 ms; P<0.001). These dissimilarities might be related to the different muscle fibre characteristics (e.g. type, size, post-mortem acidification behaviour, etc.). As for protein oxidation, significantly higher carbonyls content were found in turkey and rabbit in comparison with chicken meat (3.10 and 3.60 vs. 1.11 nmol/mg of protein; P<0.001). The lower protein oxidation level observed in chicken meat might be likely related to its lower iron content if compared to both turkey and rabbit meats. In conclusion, providing reference values, this study improved the current knowledge concerning poultry, turkey and rabbit meat quality characteristics
Functional property issues in broiler breast meat related to emerging muscle abnormalities
No full textIn the past few decades, a remarkable increase in the incidence of breast muscle abnormalities termed as white-striping (WS) and wooden-breast (WB) (normally downgraded by the poultry industry and used as raw materials to produce processed products) was observed. Thus, the present study aimed at evaluating the effect of WS and/or WB abnormalities on main compositional traits, lipid and protein oxidation and physicochemical state of water assessed by time domain nuclear magnetic resonance. Overall, if compared with controls, WS and WB groups revealed an increased (P < 0.05) moisture, fat and collagen contents coupled with reduced protein and total heme pigments levels. Otherwise, negligible modifications in fatty acid profile were found. Moreover, higher carbonyls (P < 0.05) were measured in WB and WS/WB samples if compared to normal and WS ones, and WB group also exhibited higher (P < 0.05) TBARS values. Abnormal samples showed a remarkable increase in proportion and mobility of extra-myofibrillar water fraction especially in WB and WS/WB groups. As a result, both functional and quality issues might arise when processed products are formulated including raw meats affected by WS and/or WB
Nitrogen and phosphorus excretion on commercial rabbit farms: calculations based on the input-output balance
Full text link[EN] Manure is no longer exclusively considered as a fertiliser in areas with high densities of farm animals. Efforts are being made to reduce mineral excretion or to stimulate a more environmentalfriendly use. In such a context, both from the governmental side and for the producer, a reliable calculation of the on-farm production is very useful. Based on the balance between input (feed) - output (produced rabbits, dead rabbits), the nitrogen and phosphorus on farm excretion have been calculated for different production systems, production levels and slaughter weights. For a closed farm (breeding + fattening) the most convenient expression of mineral excretion is per female on average present on the farm. The excretion amounts to 7.42 kg N and 4.76 kg P2O5 per doe/year on a commercial rabbit farm based on an average production/doe of 45 fatteners of 2.5 kg. The excretion decreases from 76 to 61 g N and from 48 to 40 g P2O5 /kg rabbit produced with increasing productivity of the farm (35 vs 50 delivered fatteners/doe/year, respectively). In an exclusively fattening unit (between 0.8 and 2.5 kg weight and a feed conversion ratio of 3.40), the excretion amounts to 38 g N and 26 g P2O5, per kg rabbit produced.Maertens, L.; Cavani, C.; Petracci, M. (2005). Nitrogen and phosphorus excretion on commercial rabbit farms: calculations based on the input-output balance. World Rabbit Science. 13(1):3-16. https://doi.org/10.4995/wrs.2005.533SWORD31613
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Effect of spaghetti-meat abnormality on quality and histological traits of broiler breast fillets
Full text linkDuring the last few years, the increasing growth rate and meat yield of modern broiler hybrids caused the appearance of several breast muscle abnormalities, such as white striping and wooden breast. Recently, a new myopathy termed spaghetti-meat (SM) characterized by extremely soft and friable pectoralis major when palpated after chilling has emerged. Since the occurrence of SM is often associated with white striping (WS), this study aimed at evaluating the effects of SM and/or WS conditions on meat quality and histological traits in broilers. For this purpose, 96 pectoralis major muscles were selected from homogeneous flocks (47 d of age and 2.8 kg of live weight at slaughter) into two independent trials and classified as follows: 24 Normal (N), 24 WS, 24 SM and 24 WS/SM. Each fillet was cut in order to separate the superficial layer from the deep one and both used to assess
proximate composition, histological features, colour, pH and protein profile. Data were analyses by two-way ANOVA using abnormality and sampling position as the main variables. Proximate composition was found to be significantly modified according the type of abnormality, especially in the superficial layer of the fillets. The SM and WS/SM groups had a remarkable decrease in total protein content coupled with an increased moisture level (p<.001), while WS group was associated with higher lipid content. Histological evaluations of abnormal samples evidenced several degenerative aspects that almost completely concern the superficial layer of the fillets. The SM samples showed poor fibres uniformity and a progressive rarefaction of the endo- and peri-mysial connective tissue. The WS fillets exhibited necrosis and lysis of fibres, fibrosis, lipidosis, loss of cross striation and vacuolar degeneration, while WS/SM fillets exhibited intermediate histological features. No relevant effect on meat colour has been detected,
however abnormal fillets showed increased yellowness (b) and ultimate pH values (p<.001). Moreover, both WS and SM abnormalities were associated with a more intense proteolytic degradation of muscle tissue (p<.001), which led to the formation of high molecular-weight protein fragments. In conclusion, both muscle myopathies mainly affect the superficial layer of pectoralis major muscle, while deep section is poorly involved. Furthermore, if compared with WS, SM abnormality is associated with a more remarkable alteration of the proximate composition and quality traits of the meat
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