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Zdolność utrzymywania wody przez mięso i jego przetwory jest ważnym aspektem zarówno z technologicznego jak i ekonomicznego punktu widzenia. Jedną z popularnych metod oznaczania zawartości wody wolnej jest metoda Graua - Hamma, która opiera się na pomiarze powierzchni plam sprasowanej próbki mięsa i nacieku. Celem pracy było zbadanie jak na wynik zawartości wody wolnej wpływa wielkość zastosowanego nacisku i czas jego działania oraz sprawdzenie czy do pomiaru powierzchni plam można zastosować program do komputerowej analizy obrazu NIS - Elements BR 2.20 (Nikon Corporation, Tokyo, Japonia). Zawartość wody wolnej oznaczano w mięsie wołowym (m. semitendinosus). Próbki o masie 0,3 g poddawano naciskowi 1, 2 i 5 kg przez czas 1, 3, 5, 7, 10 min. Powierzchnię otrzymanych plam mięsa i nacieku mierzono przy użyciu programu NIS - Elements BR 2.20. St wierdzono, że dzięki zastosowaniu programu komputerowego możliwe jest szybkie i precyzyjne uzyskanie wymiarów powierzchni plam, bez konieczności obrysowywania konturów plam czy też innych czasochłonnych zabiegów. Analiza statystyczna wykazała, że na wynik zawartości wody wolnej wpływa zarówno wielkość zastosowanego nacisku, jak i czas jego działania. Odnotowano brak statystycznie istotnych różnic pomiędzy wynikami uzyskanymi w następujących warunkach: nacisk 2 kg przez 1, 3, 5, 7 i 10 min., 1 kg przez 3, 5 , 7 i 10 min. oraz 5 kg przez 1 min. Otrzymane wyniki dają podstawę do porównywania wartości otrzymywanych przy zróżnicowanym nacisku i czasie jego działania.
The aim of the study was to investigate the possible use of nine Lactobacillus strains, previously isolated from infants faeces, as components of industrial starter cultures for yoghurt, soft white cheese and hard cheese production. There were no strong antagonistic interactions between isolates and commercial probiotics and yoghurt strains. None of isolates was able to grow at 3℃, seven grew at 7℃, all of them at 12℃ and 37℃ and only three at 45℃. In the culture media containing 10.4% NaCl at pH 6.5 growth of four isolates was detected at 12℃, whereas six strains grew at 37℃. Tested isolates did not hydrolyze casein and arginine and did not produce H₂S. Inulins (HD, IQ, TEX, HPX) and maltodextrins (low and medium dextrose equivalent) added to the culture media stimulated the growth of isolates. The properties of all isolates enable their application in soft white and hard cheeses and strains 4a, 4b and 14 in yoghurts.
The study was aimed to investigate the effect of partial back fat substitution by rape-seed oil on composition, physical and sensorial properties of comminuted meat products. Four treatments were produced: control (40% of porcine fat) and products in which 12.5, 25 and 37% of back fat was substituted by oil. Modifications in fat composition resulted in changes in water and protein content (P < 0.05). Visible fat content differed only between control and the treatment in which 37% of back fat was replaced by rape-seed oil (P < 0.05). With the increased level of substitution the production yield decreased. The substitution of back fat by rape-seed oil did not cause changes in pH values and colour parameters of products, but modified hardness, springiness, chewiness and gumminess (TPA test), as well as consistency and binding (sensory evaluated). In conclusion, it is possible to substitute up to 25% of porcine back fat by rape-seed oil in comminuted meat product without any adverse effect on its quality parameters.
Twenty strains of Lactobacillus sp., previously isolated from infants’ faeces (MODZELEWSKA et al. 2003) were evaluated for their probiotic properties such as resistance to rifampicin, neomycin, kanamycin, chloramphenicol, ampicillin, penicillin, nalidixic acid, gentamycin, colistin, oxaciclin and nitrofurantoin, survivability in the environment similar to the present in the gastrointestinal tract – pH 2 and 3 and bile salts concentration 1.2, 2.5 and 5%. All strains were resistant to colistin and nalidixic acid and susceptible to rifampicin, nitrofurantoin, chloramphenicol and ampicillin. Strains showed high survivability in pH 2 and 3. After 6 h incubation bacterial counts were at the level of 8.3-7.2 log cfu cm⁻³ compared to initial 8.7-7.2 log cfu cm⁻³. In the environment containing 1.2-5% of bile salts bacterial counts after incubation were from below 1 to 6.6 log cfu cm⁻³. Nine strains, which survived in the highest numbers in bile salts solutions, were considered as capable of surviving passage through the gastrointestinal tract, which is one of the basic requirements which probiotic strains must fulfil.
The influence of inulin HPX and potentially probiotic Lactobacillus plantarum 14 strain on microbial quality and organoleptic properties of soft cheese were studied. Also the effect of inulin on probiotic concentration was examined during 45 days of storage at 6°C. Four versions of soft cheese were produced: (1) control without synbiotic, (2) with L. plantarum 14, (3) with inulin HPX 2.5 g/100 g of cheese, (4) with inulin HPX 2.5 g/100 g of cheese and L. plantarum 14. The number of potentially probiotic bacteria was affected by the addition of inulin HPX (p<0.05). In all probiotic cheeses the concentration of potentially probiotic strain was at a recommended level of 106–107 cfu/g. Also sensory quality was positively affected by the presence of inulin in products. After production and 45 days of storage the most desirable properties possessed cheese produced with the addition of inulin HPX, followed by control cheese. Microbial quality of all cheeses was satisfactory.
W pracy określono wpływ mięśniowych białek kolagenowych na teksturę mięsa pieczonego. Surowiec do badań stanowił rostbef (m. longissimus dorsi) i ligawa (m. semitendinosus) pozyskane od młodych zwierząt. Surowiec podzielono na dwie części, z których jedną poddano obróbce termicznej. W mięsie surowym i pieczonym oznaczono profil białek kolagenowych, w mięsie pieczonym dodatkowo określono wpływ białek kolagenowych na teksturę mięsa (siła cięcia i twardość). Badane mięso charakteryzowało się niską zawartością kolagenu ogólnego i aż 10% zawartością związków niskocząsteczkowych rozpuszczalnych w wodzie. Następstwem obróbki termicznej były ubytki masy, jak również zmniejszenie zawartości kolagenowych białek nierozpuszczalnych w 0,5 M CH3COOH. Wykazano, że mięśnie różniły się profilem tekstury - ligawa odznaczała się wyższą twardością i siłą cięcia niż rostbef.
Products containing pro- and prebiotics are known as synbiotics. The benefits of pro- and prebiotics on the host include: normalization of the microbial balance in the gastrointestinal tract, increase of mineral bioavailability, reduction of cholesterol level in blood and prevention of gastrointestinal disorders. The aim of the work was to compare the apparent absorption and retention indexes in rats fed diets containing probiotic or synbiotic soft cheeses. As a probiotic, the strain Lactobacillus plantarum 14 was used, whereas as prebiotics inulin HPX and maltodextrin were used. For 10 days, the animals were fed diets consisting of 61-81% of soft cheese with probiotic (A diet), probiotic and 2,5% of inulin HPX (B diet) and probiotic and 2.5% of maltodextrin (C diet). On the basis of the magnesium concentration in the diets and the urine and faeces excreted during the last 5 days of the experiment, the apparent absorption (A) and retention (R) indexes (%, mg 5 days-1) were calculated. The apparent absorption indexes obtained did not differ statistically among the groups, although the highest value of apparent absorption (A%) was obtained in group B. The apparent retention indexes in group A were significantly higher (p < 0.05) compared to groups B and C. On the other hand, in B and C groups increased faecal mass was detected, but the inulin influence was stronger than that of maltodextrin. Although the short-term supplementation of rat diets with inulin HPX and maltodextrin did not increase magnesium absorption and retention, their use in probiotic products is reasonable because of the beneficial physiological effects.
The intake of food products containing prebiotics has a beneficial effect on the functioning of the gastrointestinal tract and may also contribute to increased mineral absorption from a diet. In the food industry prebiotics (inulins and maltodextrins) are also used because of their functional properties such as stabilizing emulsions. A study was undertaken to investigate the effect of inulin HPX and maltodextrin, applied in the production of white soft cheese as stabilizers, at a dose of 2.5%, on the bioavailability of calcium and phosphorus in rats. In the study, Wistar rats (n = 6 per group) were fed diets composed of cheese without prebiotic (control) or cheeses containing either 2.5% of inulin or maltodextrin, for 10 days. The bioavailability of the minerals was expressed by means of apparent absorption (A) and retention (R) coefficients (mg/5 days,%). The apparent Ca absorption and retention (mg/5 days) were the highest in the control group (p <0.05), whereas the A (%) and R (%) coefficients did not differ significantly between the groups. Also, the apparent absorption of P (mg/5 days) was the highest (p<0.05) in the control group and no differences in A (%), R (mg/5 days), R (%) coefficients were noted among the groups. Inulin HPX and maltodextrin used in white cheese production do not increase Ca nor P bioavailability, which suggests that the technologically-justified 2.5% dose is too low to exert a positive effect on mineral balance.
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