This thesis aims to compare four feeding strategies for ham production and evaluate their impact on the quality of the dry-cured hams. For this trial, 336 pigs with a starting body weight of 90 kg were used. Three cycles of 112 pigs each, balanced for sex and housed in 8 pens equipped with automatic feeders. Four feed treatments were administered in each cycle. In the control group (C), the animals were fed a restricted diet with a medium protein content. The animals were slaughtered at 265 days of age at a live weight of 170 kg, in accordance with the PDO specifications for dry-cured ham production. In the 'older age' (OA) group, animals were fed a restricted ration with a low protein content; animals were slaughtered at an older age (278 days) at a slaughter weight of 170 kg. The other two groups, 'younger age' (YA) and 'greater weight' (GW), were fed ad libitum with high-protein feeds. Specifically, in the YA group the slaughter weight (170 kg) was maintained unchanged, and it was reached early (237 days), while in the GW group the age at slaughter was maintained (265 days), reaching a slaughter weight of 194 kg. All hams were seasoned for 607 days; they were weighed before and after curing and after deboning. Sixty dry-cured hams were sampled and sliced for chemical analysis. To obtain the proximate composition and fatty acid profile, lean and fatty tissues were separated and then analysed. The model used for statistical analysis has sex and group diet as fixed effects. In the four different diets, the sex of the animals had a minimal impact. Compared to the C group, the OA diet group, had lower ham weight (P = 0.033) and protein content in lean tissue (P = 0.022), increased marbling (P = 0.013) and decreased proportions of intramuscular monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA; P < 0.001 and P = 0.008, respectively). The YA diet showed hams with increased fat coverage (P = 0.014) and reduced PUFA in intramuscular (P = 0.007) and subcutaneous fat (P < 0.001). Hams from the GW diet showed higher deboned hams weights compared to C (P < 0.001), higher fat coverage (P < 0.001), and a reduction of PUFAs in intramuscular (P < 0.001) and subcutaneous (P < 0.001) fat, but no change in moisture content was observed in the lean part. These results may be of great interest to breeders and ham producers, as YA and GW treatments seem to positively impact the quality of cured hams. However, further studies on the sensory quality of hams are needed to confirm the results of this thesis work.
La tesi si occupa di confrontare quattro strategie alimentari per la produzione di prosciutto crudo e di valutare l’influenza di tali metodologie sulla qualità dei prosciutti. Per questa sperimentazione sono stati utilizzati 336 suini con un peso corporeo di partenza pari a 90 kg, sono stati effettuati 3 cicli da 112 capi ciascuno, bilanciati per il sesso e messi a dimora in 8 recinti dotati di alimentatori automatici. Ad ogni ciclo sono stati somministrati 4 trattamenti alimentari. Nel gruppo di controllo (C), gli animali hanno ricevuto un’alimentazione ristretta a medio contenuto di proteina; i capi sono stati macellati a 265 giorni di età ad un peso vivo di 170 kg, secondo quanto previsto dai disciplinari dei prosciutti crudi DOP. Nel gruppo denominato “older age” (OA), gli animali sono stati alimentati con una razione ristretta a basso contenuto di proteina; i capi sono stati macellati ad un’età maggiore (278 giorni) ad un peso di macellazione di 170 kg. Gli altri due gruppi, “younger age” (YA) e “greater weight” (GW), sono stati alimentati ad libitum con mangimi ad alto contenuto proteico. In particolare, nel gruppo YA è stato mantenuto invariato il peso alla macellazione (170 kg), raggiunto precocemente (237 giorni), mentre nel gruppo GW è stata mantenuta invariata l’età alla macellazione (265 giorni), raggiungendo un peso alla macellazione di 194 kg. Tutti i prosciutti sono stati stagionati per 607 giorni; sono stati pesati prima e dopo la stagionatura e dopo il disossamento. Sono quindi stati campionati e affettati 60 prosciutti. Per ottenere la composizione approssimativa e il profilo degli acidi grassi, sono stati separati i tessuti magri da quelli grassi e poi analizzati. Il modello usato per l’analisi statistica ha come effetti fissi il sesso e la dieta del gruppo. Nelle quattro diverse diete, il sesso degli animali ha avuto un impatto trascurabile. Rispetto al gruppo C, il gruppo con dieta OA ha ottenuto un minor peso del prosciutto (P = 0.033) e contenuto di proteina nel tessuto magro (P = 0.022), l’aumento della marezzatura (P = 0.013) e la diminuzione della proporzione di acidi grassi monoinsaturi (MUFA) e polinsaturi (PUFA) intramuscolare (P < 0.001 e P = 0.008, rispettivamente). La dieta YA ha mostrato prosciutti con un aumento di copertura di grasso (P = 0.014) e una riduzione dei PUFA nel grasso intramuscolare (P = 0.007) e sottocutaneo (P < 0.001). I prosciutti derivanti dalla dieta GW hanno mostrato pesi maggiori del prosciutto disossato (P < 0.001), una maggiore copertura di grasso (P < 0.001), con una riduzione dei PUFA nel grasso intramuscolare (P < 0.001) e sottocutaneo (P < 0.001), non modificando però il contenuto di umidità nella parte magra. Questi risultati possono essere di grande interesse per gli allevatori ed i produttori di prosciutto, in quanto i trattamenti YA e GW sembrano impattare positivamente sulla qualità dei prosciutti stagionati. Sono tuttavia necessari ulteriori studi sulla qualità sensoriale dei prosciutti, in modo da poter confermare i risultati di questo lavoro di tesi.
"Caratteristiche tecnologiche e composizione chimica del prosciutto crudo DOP"
DELMARCO, MATTEO
2022/2023
Abstract
This thesis aims to compare four feeding strategies for ham production and evaluate their impact on the quality of the dry-cured hams. For this trial, 336 pigs with a starting body weight of 90 kg were used. Three cycles of 112 pigs each, balanced for sex and housed in 8 pens equipped with automatic feeders. Four feed treatments were administered in each cycle. In the control group (C), the animals were fed a restricted diet with a medium protein content. The animals were slaughtered at 265 days of age at a live weight of 170 kg, in accordance with the PDO specifications for dry-cured ham production. In the 'older age' (OA) group, animals were fed a restricted ration with a low protein content; animals were slaughtered at an older age (278 days) at a slaughter weight of 170 kg. The other two groups, 'younger age' (YA) and 'greater weight' (GW), were fed ad libitum with high-protein feeds. Specifically, in the YA group the slaughter weight (170 kg) was maintained unchanged, and it was reached early (237 days), while in the GW group the age at slaughter was maintained (265 days), reaching a slaughter weight of 194 kg. All hams were seasoned for 607 days; they were weighed before and after curing and after deboning. Sixty dry-cured hams were sampled and sliced for chemical analysis. To obtain the proximate composition and fatty acid profile, lean and fatty tissues were separated and then analysed. The model used for statistical analysis has sex and group diet as fixed effects. In the four different diets, the sex of the animals had a minimal impact. Compared to the C group, the OA diet group, had lower ham weight (P = 0.033) and protein content in lean tissue (P = 0.022), increased marbling (P = 0.013) and decreased proportions of intramuscular monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA; P < 0.001 and P = 0.008, respectively). The YA diet showed hams with increased fat coverage (P = 0.014) and reduced PUFA in intramuscular (P = 0.007) and subcutaneous fat (P < 0.001). Hams from the GW diet showed higher deboned hams weights compared to C (P < 0.001), higher fat coverage (P < 0.001), and a reduction of PUFAs in intramuscular (P < 0.001) and subcutaneous (P < 0.001) fat, but no change in moisture content was observed in the lean part. These results may be of great interest to breeders and ham producers, as YA and GW treatments seem to positively impact the quality of cured hams. However, further studies on the sensory quality of hams are needed to confirm the results of this thesis work.File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.12608/59104