Pepsin enzyme was used to pretreat the bovine skin at the rate of 5, 15, and 25 units of enzyme/g of skin to recover gelatin, and the recovered gelatins were referred to as Pe5, Pe15, and Pe25, respectively. The gelatin yield increased significantly (p < 0.05) from 18.17% for Pe5 to 24.67% for Pe25 as the level of pepsin increased, but the corresponding gel strength and viscosity decreased significantly (p < 0.05) from 215.49 to 56.06 g and 9.17 to 8.17 mPa·s for Pe5 and Pe25, respectively. β- and α1- and α2-chains were degraded entirely in all the gelatins samples as observed in protein pattern elaborated by gel electrophoresis. 1H nuclear magnetic resonance (1H NMR) analysis indicated the coiled structure of gelatin protein chains. The lowest amide III amplitude of Pe25 as found by Fourier transform infrared (FTIR) spectroscopy indicated that α-helix structure of protein chains were lost to more irregular coiled structure. Thus, it could be summarized that pepsin might be used at the lower level (5 units/g of wet skin) to extract gelatin from bovine skin with good functional properties and at higher level (15/25 units/g of wet skin) to obtain gelatin of industrial grade with high yield.
Actinidin was used to pretreat the bovine hide and ultrasonic wave (53 kHz and 500 W) was used for the time durations of 2, 4 and 6 h at 60 °C to extract gelatin samples (UA2, UA4 and UA6, respectively). Control (UAC) gelatin was extracted using ultrasound for 6 h at 60 °C without enzyme pretreatment. There was significant (p < 0.05) increase in gelatin yield as the time duration of ultrasound treatment increased with UA6 giving the highest yield of 19.65%. Gel strength and viscosity of UAC and UA6 extracted gelatin samples were 627.53 and 502.16 g and 16.33 and 15.60 mPa.s, respectively. Longer duration of ultrasound treatment increased amino acids content of the extracted gelatin and UAC exhibited the highest content of amino acids. Progressive degradation of polypeptide chains was observed in the protein pattern of the extracted gelatin as the time duration of ultrasound extraction increased. Fourier transform infrared (FTIR) spectroscopy depicted loss of molecular order and degradation in UA6. Scanning electron microscopy (SEM) revealed protein aggregation and network formation in the gelatin samples with increasing time of ultrasound treatment. The study indicated that ultrasound assisted gelatin extraction using actinidin exhibited high yield with good quality gelatin.
The sharpness of the knife used for slaughter is of the utmost importance from an animal welfare perspective. The quantification of knife sharpness is almost impossible in abattoirs. The sharpness of the knife blade used to slaughter an animal, as well as its effects on animals’ pain and stress levels, is an important area of investigation that needs to be addressed. The objective of this study was to evaluate the effects of knife sharpness on blood biochemical parameters, plasma catecholamines, and electroencephalographic (EEG) responses. Twenty Brahman crossbred steers were either subjected to slaughter with a sharp knife (n = 10) or a commercial sharp knife (n = 10); knife sharpness was measured with the ANAGO® sharpness tester. There was significant increase in adrenaline (p < 0.0001), glucose (p = 0.0167), creatinine kinase (p = 0.0123) and lactate dehydrogenase (p = 0.0151) at post-slaughter compared to pre-slaughter in commercial sharp knife group than in thesharp knife group. A significant increase was observed in the median frequency (p < 0.0001) and total power (p < 0.0001) of the EEG, the parameters for pain and stress, in the animals slaughtered with the commercial sharp knife than those slaughtered with the sharp knife. Thus, EEG results also supported the hormonal and biochemical results. From the results, it is concluded that animals slaughtered with a sharp knife experienced the least amount of pain and stress compared to those slaughtered with a commercial sharp knife.
Meat of non-descript type old female goat of more than two years age and meat of young castrated male goat of around 9 months age were procured, chilled to 4 +/- 1 degrees C for 24 hrs and then frozen stored at -10 +/- 1 degrees C in the form of chunks and mince, packaged in low density polythene (LDPE) -300 g (gauge) and high density polythene (HDPE) -200 g for 0, 4, 8, 12 and 16 weeks. Samples of meat were evaluated for pH, water holding capacity (WHC), salt soluble protein (SSP), water soluble protein (WSP), non protein nitrogen (NPN), thiobarbituric acid value (TBA) and microbiological load in terms of aerobic plate count (APC). Overall there was significant (P<0.01) rise in pH as the storage period progressed. There was nonsignificant (P<0.01) difference between treatments. The average WHC increased significantly (P<0.01) upto 8 weeks (32.87%) and then started decreasing and was lowest at 16 weeks (24.14%). There was significant decrease (P<0.01) in WSP as the storage period increased from 0 week to 16 weeks. The average WSP of old female goat meat kept as chunk in LDPE and mince in HDPE increased significantly (P<0.01) with respect to young male goat meat (kept as chunk in LDPE and mince in HDPE). There was significant (P<0.01) reduction in SSP as the storage period progressed but there was non-significant decrease between 4 weeks and 8 weeks. SSP was 8.53% at 0 week and 4.58 at 16 weeks. The average TBA-values increased significantly (P<0.01) at each storage interval. The value increased from 0.28 (at 0 week) to 0.65 (at 16 weeks) mg of malonaldehyde/kg of meat. Mince kept in HDPE of old female goat had significantly (P<0.01) higher TBA value than other treatments. There was significant (P<0.01) reduction (5.65 log(10) cfu/g at 0 week and 5.26 log(10) cfu/g at 16 weeks) at each storage interval in APC as the storage period increased.