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1.
Zmanjšanje uporabe nitritov in polifosfatov pri predelavi sušenih klobas
Manja Ozmec, 2021, magistrsko delo

Opis: Cilj naloge je bil ugotoviti, kakšen je vpliv zmanjšanja količine aditivov (natrijevega nitrita in polifosfatov) ter dodatka natrijevega askorbata na kakovost sušenih klobas. V ta namen so bile oblikovane štiri poskusne skupine. Prva skupina klobas (kontrola) je bila izdelana po že obstoječi recepturi predelovalca (uporaba 0,2 % polifosfatov ter 2,2 % mesarske soli z 0,5 % natrijevega nitrita). Druga skupina klobas je bila narejena s 50 % zmanjšano vsebnostjo natrijevega nitrita, v tretji skupini je bil klobasam poleg 50 % zmanjšane vsebnosti nitritov dodan natrijev askorbat (225 mg/kg). Četrta skupina je bila oblikovana po standardni recepturi, vendar brez polifosfatov. Postopek predelave je trajal 24 dni. Z izjemo vpliva na oksidativno stabilnosti in nekoliko manjših izgub (osuška) ni bilo ugotovljenih pomembnih vplivov zmanjšanja natrijevega nitrita na fizikalno-kemijske lastnosti klobas, prav tako se razlike niso izrazile pri senzoričnih lastnostih, niti pri mikrobiološki sliki. Analize so pokazale, da dodatek natrijevega askorbata v kombinaciji z zmanjšanim dodatkom nitritov pozitivno vpliva na stabilnost barve in antioksidativne lastnosti. V primeru skupine klobas brez dodanih fosfatov ni bilo ugotovljenega pomembnega vpliva pri izgubi (osušek), ne pri reoloških in senzoričnih lastnostih, ugotovljena pa je bila večja oksidacija in vpliv na instrumentalno izmerjeno barvo. Na splošno so bile razlike majhne in slabo opazne, kar je potrdila tudi senzorična analiza.
Ključne besede: sušena klobasa, nitrit, polifosfati, askorbat
Objavljeno: 17.09.2021; Ogledov: 105; Prenosov: 15
.pdf Celotno besedilo (1,04 MB)

2.
Vpliv spola in stopnje soljenja na kakovost pršuta
Gregor Sok, 2020, magistrsko delo

Opis: Cilj naloge je bil ugotoviti, kako spol prašiča in dolžina soljenja stegen vplivata na fizikalno-kemijske in teksturne lastnosti pršuta. V ta namen smo predelali stegna dvanajstih prašičev, šestih kastratov in šestih svinjk. Vse leve noge smo uporabili za krajše (10 dni), vse desne noge pa za daljše soljenje (18 dni). Vsi ostali postopki med predelavo so bili enaki. Po zaključenem zorenju smo za nadaljnje analize odvzeli vzorce dveh mišic, semimembranosus (SM) in biceps femoris (BF). Stegna kastratov so se od stegen svinjk razlikovala le v zamaščenosti, kar se je med predelavo, v fazi soljenja, odrazilo v manjši izgubi mase. Po zaključenem zorenju se stegna kastratov in svinjk niso razlikovala v kemijsko-fizikalnih lastnostih, razen v indeksu proteolize, ki je bil manjši v mišičnini kastratov, kar kaže na manj izražene proteolitične procese pri slednjih. Skladno s tem je analiza teksturnih lastnosti pokazala, da je bil po zaključku zorenja pršut iz svinjk (ugotovljeno za mišico BF), bolj mehak, manj koheziven in manj gumijast. Vpliv spola je značilno vplival na barvo mastnine in mišičnine po zaključku zorenja, in sicer je bila barva mastnine in barva obeh mišic BF in SM pri svinjkah svetlejša kot pri kastratih. Trajanje soljenja je vplivalo na vsebnost soli v pršutu, ki je bila pri krajšem soljenju značilno zmanjšana. Prav tako je krajše soljenje vplivalo na teksturne lastnosti pršuta, saj je bil pršut, ki je bil izpostavljen krajšemu soljenju mehkejši (SM in BF), mišica SM je bila tudi manj kohezivna, gumijasta in žvečljiva.
Ključne besede: pršut, spol, soljenje, kakovost
Objavljeno: 30.09.2020; Ogledov: 248; Prenosov: 41
.pdf Celotno besedilo (1,61 MB)

3.
Določanje kakovosti maščob v prašičjem mesu in slanini z bližnjo infrardečo spektroskopijo
Valerija Jurkovič, 2019, magistrsko delo

Opis: Preučevali smo točnost napovedovanja maščobnokislinske sestave maščobnega ter mišičnega tkiva z bližnjo infrardečo (NIR) spektroskopijo. Modele za napovedovanje smo razvili na osnovi spektrov vzorcev maščobnega in mišičnega tkiva ter referenčnih vrednosti kemijske analize za posamezne maščobne kisline (MK) in skupine MK (nasičene ̶ NMK, enkrat nenasičene ̶̶ ENMK, večkrat nasičene ̶ VNMK, n-3 in n-6 VNMK). Za napovedovanje smo uporabili laboratorijski NIR-spektrometer (model NIR System 6500) ter območje valovnih dolžin od 400 do 2500 nm. Vzorce maščobnega tkiva smo posneli v intaktni, vzorce mišic pa v homogenizirani obliki. Kakovost umeritvenih enačb smo ovrednotili s pomočjo parametrov standardna napaka kalibracije (seC), standardna napaka navzkrižne validacije (seCV), determinacijski koeficient kalibracije (R2C) in navzkrižne validacije (R2CV) ter parametrom RPD (razmerje med standardnim odklonom referenčnih vrednosti in seCV). Za zanesljive napovedi mora RPD presegati 3,0, vrednosti RPD med 2,0 in 3,0 pa kažejo na uporabnost enačb za grobo spremljanje. Rezultati kažejo precej uspešno napovedovanje skupin MK v podkožnem maščobnem tkivu z NIR-spektroskopijo. Najboljši rezultat smo dobili pri VNMK, kjer sta R2CV in RPD znašala 0,92 in 3,7, ter pri n-6 VNMK, kjer smo dosegli R2CV 0,92 in RPD 3,6. Za NMK sta R2CV in RPD znašala 0,76 in 2,0, pri ENMK 0,88 in 2,9 ter pri n-3 VNMK 0,66 in 1,7. Pri posameznih MK smo najboljše rezultate dobili pri vsoti C18:1 (R2CV = 0,85, RPD = 2,6), vendar je bil RPD pri večini MK pod 2,0. Pri skupinah MK so, z izjemo razmerja VNMK n-6/n-3, dobljene kalibracije uporabne za (grobo) spremljanje. Maščobnokislinske sestave mišičnega tkiva nismo uspeli zadovoljivo napovedati.
Ključne besede: NIR-spektroskopija, maščobnokislinska sestava, meso, slanina, prašiči
Objavljeno: 06.09.2019; Ogledov: 963; Prenosov: 71
.pdf Celotno besedilo (887,09 KB)

4.
Ekonomika dopolnilne dejavnosti predelave mesa na lastni kmetiji
Nina Filipič, 2018, diplomsko delo/naloga

Opis: Osnovni cilj raziskave je bila ekonomika predelave mesa na lastni kmetiji. Osnovna dejavnost na kmetiji je pitanje prašičev. Kmetija se odloča o nadaljnji predelavi mesa v končne izdelke, pri čemer bi bila glavna dejavnost na kmetiji izdelava prleške tünke po starih običajih. V ta namen je bil razvit tehnološko-ekonomski model predelave mesa v različne domače izdelke. Osrednja uporabljena metoda je bila metoda kalkulacije skupnih stroškov in ocena koeficienta ekonomičnosti (Ke). Rezultati analize kažejo, da je pitanje prašičev ob upoštevanju lastne cene žit ekonomsko upravičeno (Ke = 1,04). Koeficient ekonomičnosti predelave mesa v prleško tünko (Ke = 1,41), domače krvavice (Ke = 3,30), suhe domače klobase (Ke = 2,90), domačo tlačenko (Ke = 0,06) in ocvirke (Ke = 1,19) je pokazal, da je predelava ekonomsko precej bolj učinkovita kot le pitanje prašičev. Izjema pri predelavi mesa je predelava v domačo tlačenko, kjer rezultati raziskave kažejo, da je proizvodnja ekonomsko neučinkovita, saj je ocenjena vrednost koeficienta ekonomičnosti nižja od vrednosti 1.
Ključne besede: ekonomika / dopolnilna dejavnost / predelava mesa
Objavljeno: 21.09.2018; Ogledov: 674; Prenosov: 117
.pdf Celotno besedilo (922,29 KB)

5.
Primerjava kakovosti mesa med merjasci in kastrati - etiologija trdote
Jasmina Bajc, 2018, magistrsko delo/naloga

Opis: Zaradi predvidene prepovedi kirurške kastracije pujskov v EU so potrebne raziskave alternativ; ena od njih, ki naj bi se najverjetneje uveljavila, je reja merjascev. Kljub nekaterim prednostim, ki jih reja merjascev predstavlja v primerjavi s kastrati, pa obstajajo indikacije, da je kakovost mesa merjascev drugačna. Kaže se problem večje trdote mesa, etiologija pojava pa še ni raziskana. Zato je bil osnovni cilj naše študije ugotoviti, ali obstajajo razlike v trdoti mesa med merjasci in kastrati ter s čim lahko te razlike pojasnimo. V raziskavi smo izmerili lastnosti kakovosti klavnega trupa (DM5), lastnosti kakovosti mesa (pH, barva mesa, sposobnost vezave vode, rezna trdota) ter določili kemijsko sestavo mesa (vsebnost proteinov, intramuskularne maščobe in vode, vsebnost skupnega mišičnega pigmenta, kolagena in oksidacije proteinov). Zbrane podatke smo statistično analizirali s pomočjo programa SAS. V raziskavi smo ugotovili, da imajo merjasci več celokupnega kolagena (34,5 %, P < 0,05), manj intramuskularne maščobe (66 %, P < 0,05), večji obseg oksidacije proteinov (59,5 % večja vsebnost karbonilnih skupin, P < 0,05) in slabšo sposobnost vezave vode (35,5 % večja izceja mesnega soka ter 21 % večje izgube pri kuhanju, P < 0,05) v primerjavi s kastrati. Vse zgoraj naštete lastnosti lahko pojasnijo ugotovljeno večjo trdoto mesa; ta je bila pri merjascih večja za 36,6 % (P < 0,05).
Ključne besede: merjasci, kastrati, trdota, kakovost mesa
Objavljeno: 23.04.2018; Ogledov: 747; Prenosov: 74
.pdf Celotno besedilo (912,61 KB)

6.
Effect of immunocastration on performance of Slovenian pig fatteners
Martin Škrlep, Nina Batorek Lukač, Blaž Šegula, Marta Zajec, Stane Košorok, Marija Glavač-Vnuk, Valentina Kubale, Gregor Fazarinc, Marjeta Čandek-Potokar, 2011, izvirni znanstveni članek

Opis: The influence of the immunocastration (immunisation against GnRH) on pig performance (growth, carcass and meat quality traits) was investigated in two parallel experiments (on two farms) with two crossbreeds – G1 (50% Duroc) and G2 (50% Pietrain). Within the crossbreed, the pigs were assigned to three experimental groups; entire males (EM, n=49), immunocastrates (IC, n=45) and surgical castrates (SC, n=45). Those assigned to IC group were vaccinated at the age of 12 and 19 weeks. Pigs were individually housed, their feed intake (ad libitum) and weight (at 12, 19 and 24 weeks) were recorded. At the age of 24 weeks, the pigs were slaughtered and their carcass and meat quality traits were assessed. We hypothesized that treatment response could have been different in two crossbreeds. However the interaction was insignificant, thus the treatment effect is presented on pooled results for both crossbreeds. Until the revaccination, IC were similar to EM pigs, thereafter they exhibited an increase in feed intake and growth rate. Overall, they presented an advantage in growth rate and feed efficiency as compared to SC. They also exhibited better carcass properties as SC without any major effect on meat quality. The present study provides the initial information on the immunocastration effect in Slovenian herds that should further be supported by testing it in usual rearing conditions and group housing.
Ključne besede: pig, immunocastration, growth performance, carcass properties, meat quality
Objavljeno: 24.08.2017; Ogledov: 906; Prenosov: 57
.pdf Celotno besedilo (122,14 KB)
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7.
An attempt to predict conformation and fatness in bulls by means of artificial neural networks using weight, age and breed composition information
Marjeta Čandek-Potokar, Maja Prevolnik Povše, Martin Škrlep, Maria Font-I-Furnols, Marjana Novič, 2015, izvirni znanstveni članek

Opis: The present study aimed to predict conformation and fatness grades in bulls based on data available at slaughter (carcass weight, age and breed proportions) by means of counter-propagation artificial neural networks (ANN). For chemometric analysis, 5893 bull carcasses (n=2948 and n=2945 for calibration and testing of models, respectively) were randomly selected from the initial data set (n≈27000; one abattoir, one classifier, three years period). Different ANN models were developed for conformation and fatness by varying the net size and the number of epochs. Tested net parameters did not have a notable effect on models’ quality. Respecting the tolerance of ±1 subclass between the actual and predicted value (as allowed by European Union legislation for on-spot checks), the matching between the classifier and ANN grading was 73.6 and 64.9% for conformation and fatness, respectively. Success rate of prediction was positively related to the frequency of carcasses in the class.
Ključne besede: govedo, goveje meso, mastnost mesa, struktura mesa, klavna teža, ANN modeli, modeli za napovedovanje
Objavljeno: 24.07.2017; Ogledov: 1033; Prenosov: 302
.pdf Celotno besedilo (1,12 MB)
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8.
Effect of birth weight and sex on pre-weaning growth rate of piglets
Dejan Škorjanc, Maksimiljan Brus, Marjeta Čandek-Potokar, izvirni znanstveni članek

Opis: A study was conducted to find out the effect of birth weight and sex on growth rate of piglets in pre-weaning period. A total of 466 piglets from 48 litters of multiparous sows (Landrace) were involved in the experiment. Using a clustering approach piglets were assigned into three birth weight groups (Heavy (H), Intermediate (I), Light (L)). For the analysis of growth performance, pigs were weighed every 7 days until weaning at 28 days of age and average daily gain (ADG) was calculated. During lactation, body weight of L piglets was 5.5-fold increased, whereas the increase in I and H piglets were only 4.7-fold and 3.4-fold, respectively. Piglets of L group were significantly lighter at all studied ages compared to piglets of I and H group. The highest ADG was noted in the second week for all three groups; thereafter it decreased in H and L piglets (24% and 17%, respectively). The average birth weight of piglets was positively and significantly correlated with body weight at days 7, 14, 21 and 28. Sex did not affect significantly the ADG of the investigated animals during the four weeks of lactation. The present results indicate that neither milk production after the second week of lactation nor consumption of creep feed are sufficient enough to cover nutrition needs of fast growing piglets. There’s still a lack of optimization of nutrition in pre-weaning period especially for heavier piglets with their higher growth potential.
Ključne besede: piglets, barrow, gilts, birth weight, pre-weaning growth rate
Objavljeno: 20.07.2017; Ogledov: 922; Prenosov: 259
.pdf Celotno besedilo (90,34 KB)
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9.
The effect of dietary fibre content on skatole and indole production in faeces of immunocatrsted male pigs
Martin Škrlep, Nina Batorek Lukač, Maja Prevolnik Povše, Urška Tomažin, Etienne Labussière, Marjeta Čandek-Potokar, 2015, objavljeni znanstveni prispevek na konferenci

Opis: The effect of dietary fibre content on intestinal production of indolic compounds was studied in immunocastrated pigs (IC). In addition, entire males (EM) and IC were compared on control diet (with low fibre content). For the study 32 crossbred pigs were assigned, within a litter to 4 treatment groups; 24 pigs were immunocastrated (at the age of 77 and 112 days) and 8 pigs were kept as entire males (EM). IC were split into three groups (IC_H, IC_M and IC_L) fed three diets differing in crude fibre (34, 60 and 80 g/kg dry matter, respectively) and net energy (NE) (10.0, 9.3, 8.5 MJ NE/kg/DM, respectively). EM were fed high NE i.e. low fibre diet. The experiment started when pigs were 84 days old and finished at the age of 172 days, when pigs were sent to slaughter. Skatole and indole concentrations were determined in the samples of intestinal content taken from caecum (CE), ascending (AC) and descending colon (DC). The concentration of indole was the highest in CE and proximal part of the colon, while skatole concentration increased in the distal parts of the large intestine. Concentrations of indolic compounds did not differ between EM and IC that were fed the same diet. Lowering dietary NE by inclusion of high fibre ingredients reduced the production of indole in the intestinal content of IC pigs, whereas the production of skatole was not affected.
Ključne besede: indole, skatole, dietary fibres, pig, entire males, immunocastrates, pig nutrition, immunocastration
Objavljeno: 20.07.2017; Ogledov: 521; Prenosov: 87
.pdf Celotno besedilo (561,86 KB)
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10.
Carcass and meat quality traits of pig fatteners from Slovenian breeding programme
Maja Prevolnik Povše, Martin Škrlep, Dejan Škorjanc, Marjeta Čandek-Potokar, 2008, objavljeni znanstveni prispevek na konferenci

Opis: The aim of the present study was the comparison of carcass and meat quality traits of commercial pigs of various crossbreeds from two major Slovenian herds. The analysis is based on phenotypic data from field trials which have been collected in the last past five years within the Slovenian breeding programme. Important differences in carcass traits were observed between two herds and were associated to different crossbreeds used. In spite of that economically important result on the slaughter line (lean meat %) was similar for both herds. Meat quality traits were also significantly different between the two herds. Again, the difference could be ascribed to crossbreeds used. However, since the herd effect is connected with abattoir effect, different ante-mortem conditions and/or lower robustness of these animals to premortal stress could also be contributed to the observed differences. The presented results give important information on the state-of-the-art regarding meat quality of Slovenian pigs.
Ključne besede: pigs, carcass quality, meat, breeding programs, Slovenia
Objavljeno: 13.07.2017; Ogledov: 792; Prenosov: 71
.pdf Celotno besedilo (140,96 KB)
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