Barbara Jankowska

The effect of muscle, cooking method and final internal temperature on quality parameters of beef roast

The aim of the study was to evaluate the influence of cooking conditions (dry air and steam) and final internal temperature (75, 85, 95°C) on the physico-chemical properties of beef infraspinatus (INF) and semimembranosus (SEM) muscles as well as their tenderness and juiciness. Cooking method and temperature influenced moisture, total collagen content in cooked meat and cooking loss, whereas muscle type affected fat, total collagen content and cooking loss. Warner-Bratzler shear force values were affected by cooking method, which also influenced juiciness of roasts. Temperature affected tenderness and juiciness, whereas muscle type influenced juiciness. The most desirable tenderness had INF heated in steam and dry air to 95°C. Processing SEM in dry air to 85 and 95°C lowered the juiciness of the roasts. There were significant correlations between physico-chemical, sensorial and image attributes, however high accuracy of prediction (r(2)>0.8) was achieved only for SEM muscle.

The composition and properties of beaver (Castor fiber) meat

We analyzed the meat composition of ten females and seven males of sexually mature European beavers (Castor fiber L.). Cutting yield, percentage of particular elements, and chemical composition of the meat were determined. On average, a beaver carcass constitutes 48.6% of beaver body mass and contains 62.8% of meat, 14.5% of fat and 22.4% of bones. The thigh was found to be the largest and most valuable element constituting 33.4% of carcass weight and containing 66.7% of meat. Beaver meat has a high concentration of protein (20.9–21.8% wet wt.) and minerals (1.27–1.31%). The fat was characterized by a high proportion of polyunsaturated fatty acids (48.0–53.1%).

Slaughter yield and growth performance indexes of pikeperch (Sander lucioperca (L.)) selects reared in recirculating aquaculture systems at suboptimal temperatures

Abstract The aim of the study was to determine the impact diet has on the basic growth performance indexes and slaughter yield of pikeperch selects (body weight > 1.35 kg). Tagging the individual fish with PIT tags also permitted determining the impact of sex on the studied growth performance indexes. The fish were fed two diets with protein/fat/carbohydrate ratios of 50.5/11.8/29.4 in group I and 47.1/14.1/29.0 in group II. Neither the diets nor the sex of the fish has a significant impact on the final body weight or condition of the pikeperch (P > 0.05). Significant differences were noted between the relative indicators of pikeperch growth performance (SGR and DGR) (impact of diet and sex; P < 0.05). Among the growth performance indexes analyzed, e.g., viscerosomatic (VSI), hepatosomatic (HSI), and gonadosomatic (GSI), statistically significant differences were noted with regard to HSI (impact of diet and sex) and GSI (impact of sex) (P < 0.05). The analysis of the relative values of the pikeperch body parts studied (expressed in % body weight) indicated that the studied parameters had significant impacts on the slaughter yield of the viscera (impact of sex) and skin (impact of diet), as well as on gutted whole fish, gutted and headed whole fish, fillets with skin, and skinned fillets (impact of sex) (P < 0.05). The slaughter yields of the skinned fillets of males from both dietary treatments were approximately 5% higher than those of the females.

Slaughter yield and fatty acid profiles of fillets of pike (Esox lucius L.) caught before and after spawning

Abstract The aim of the study was to determine the impact pike fishing season (before spawning in fall (group A) and after spawning in spring (group B)) had on the slaughter yield and fillet fatty acid profile. The slaughter yield of fillets with skin and skinned fillets from the group B fish was significantly lower (by approximately 7.5% of body weight). The fatty acid profile of the fish meat from the groups examined differed significantly. The fillets of pike caught before spawning were dominated by unsaturated fatty acids (UFA), while those from fish caught after spawning had mainly saturated fatty acids (SFA). The share of polyunsaturated fatty acids (PUFA) in the fillets of fish that had spawned was sixfold lower, and the n-3 PUFA differences were nearly ninefold. The content of eicosapentaenoic (EPA) and docosahexaenoic (DHA) fatty acids in fillets of fish that had spawned was ninefold lower than in those that had not yet done so. Consequently, the ratio of n-3 PUFA/n-6 PUFA in pike from group A was over three times higher than that in the fish that had spawned (2.61 vs 0.82). Fillets from pike that have spawned are a significantly poorer source of valuable fatty acids for consumers.

Impact of feeding juvenile pikeperch (Sander lucioperca (L.)) diets supplemented with vegetable oils on proximate body composition and fatty acid profile

Impact of feeding juvenile pikeperch (Sander lucioperca (L.)) diets supplemented with vegetable oils on proximate body composition and fatty acid profile Juvenile pikeperch, Sander lucioperca (L.) were reared in recirculating aquaculture systems for 55 days and fed a commercial trout diet (group CD) or diets supplemented with the following vegetable oils (VO): rapeseed (group RO), soy (group SO), sunflower (group SFO). The level of feed supplementation with VO was 84% of the total crude fat (CF), which was achieved by adding 160 g VO kg-1 feed to the commercial feed base that contained 30 g CF kg-1 feed. The diets tested did not have a significant impact on the proximate composition of the whole fish, fillets, or viscera (P > 0.05). Significant differences were noted in the protein and fat contents of the pikeperch livers; these were significantly higher in the groups fed diets supplemented with VO (P < 0.05). The fatty acid (FA) profiles of the pikeperch body parts (whole fish, fillets, viscera, liver) analyzed reflected the proximate composition of the diets applied. The FA profiles of pikeperch muscles were the most stable. The diets tested did not have a significant impact in the fillets of fish from the VO groups on the value of summed products of polyunsaturated FA from the n-3 family (n-3 PUFA) to the PUFA from the n-6 family (n-6 PUFA) (n-3/n-6 ratio) (P > 0.05). They were, however, significantly lower than the values noted in group CD (P < 0.05) (1.03-2.07 vs. 3.50). Wpływ żywienia juwenalnego sandacza (Sander lucioperca (L.)) paszami suplementowanymi olejami roślinnymi na podstawowy skład chemiczny ciała i profile kwasów tłuszczowych Młdocianego sandacza (początkowa masa ciała ok. 100 g) podchowywano w obiegach recyrkulacyjnych przez 55 dni i żywiono komercyjną paszą pstrągową (grupa CD) lub paszami suplementowanymi następującymi olejami roślinnymi (VO): rzepakowym (grupa RO), sojowym (grupa SO) lub słonecznikowym (grupa SFO). Poziom suplementacji pasz VO wynosił 84% całkowitego tłuszczu surowego (CF) - do komercyjnej mieszanki bazowej zawierającej 30 g CF kg-1 paszy dodawano 160 g VO kg-1 paszy. Podstawowy skład chemiczny pasz był podobny, a profile kwasów tłuszczowych (FA) w nich zawartych odzwierciedlały skład chemiczny olejów, którymi były suplementowane (tabela 1). Żywienie testowanymi paszami nie wpłynęło istotnie na wartości wskaźników wzrostu ryb i podstawowy skład chemiczny całej ryby, filetów i trzewi (P > 0,05; tabela 2). Odnotowano natomiast istotne różnice w zawartości białka i tłuszczu w wątrobie sandacza. Stwierdzono, że zawartość białka w grupach RO i SO była istotnie niższa niż u ryb z grup CD i SFO (P < 0,05). Poziom tłuszczu w wątrobie ryb z grup VO był wyższy od stwierdzonego w grupie CD, a w przypadku grup RO i SO różnice te były istotne statystycznie (P < 0,05; tabela 2). Profile FA analizowanych części ciała sandacza (cała ryba, filet, trzewia i wątroba) odzwierciedlały skład chemiczny stosowanych pasz (tabela 1, 3, 4, 5, 6). Udział wszystkich analizowanych grup FA, tj. nasyconych (SFA), nienasyconych (USFA), monoenowych (MUFA), polienowych (PUFA), polienowych z rodziny n-3 (n-3 PUFA) i polienowych z rodziny n-6 (n-6 PUFA) w całym ciele, trzewiach i wątrobie był istotnie determinowany stosowaną dietą (P < 0,05; tabela 3, 5, 6). Najbardziej stabilny był skład FA mięśni sandacza (tabela 4). W filetach ryb z grup VO nie stwierdzono istotnego wpływu żywienia testowanymi paszami na wartości ilorazów n-3 PUFA do n-6 PUFA (stosunek n-3/n-6) (P > 0,05). Były one jednak istotnie niższe niż w grupie CD (P < 0,05) (1,03-2,07 vs 3,50).