Physiochemical, fatty acids, lipid oxidation, sensory characteristics and consumer acceptance of warthog cabanossi produced with pork backfat and fat-tailed sheep backfat
- Authors: Mahachi, Leo Nyikadzino
- Date: 2017
- Subjects: Fatty acids Lipids -- Oxidation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/6259 , vital:29530
- Description: The objective of this study was to determine the effect of different fat inclusion levels and fat types on the physical and chemical attributes, lipid oxidation, fatty acid composition and sensory characteristics of warthog cabanossi. To achieve this, three types of cabanossi with different pork backfat levels (10 percent, 20 percent and 30 percent) were produced for the first experiment. The results from the study showed that different inclusion levels of pork backfat had an influence (P ≤ 0.05) on the physicochemical and fatty acid composition of warthog cabanossi but did not influence lipid oxidation (P > 0.05). The highest (P ≤0.05) pH, weight and moisture decline was observed in the 10 percent pork backfat cabanossi compared to the 20 percent and 30 percent treatments. However, no differences (P > 0.05) in the water activity of the product were observed. As expected total fat was lower in the 10 percent fat treatment and increased concomitantly. Similarly, protein, ash and salt were higher in the 10 percent fat cabanossi and decreased concomitantly. Differences in the fatty acid composition were observed between treatments. Furthermore, backfat level affected the sensory attributes and consumer acceptance of the cabanossi. Ten percent backfat cabanossi was scored higher (P ≤0.05) for most sensory attributes. Consequently, it was observed that the consumer panel preferred and scored the 10 percent fat cabanossi higher with regards to appearance and taste. In the second experiment, two cabanossi treatments of different fat types (pork backfat and fat-tailed sheep backfat) were produced. The weight loss, moisture content, pH, water activity and salt content did not differ (P > 0.05) between the two cabanossi products. However, there were differences (P ≤0.05) in the protein, fat and ash contents; where protein and ash were higher in the pork backfat cabanossi whilst fat was higher in the sheep backfat cabanossi. Thiobarbituric reactive substances (TBARS) were similar (P > 0.05) between the two fat types cabanossi which could be explained by similar fatty acid profiles being reported for the two cabanossi although the n-6:n-3 ratio was higher (P ≤0.05) in sheep backfat cabanossi. Results from the descriptive sensory analysis showed two distinct products (P ≤0.01) where pork backfat cabanossi scored higher for most attributes. However, the lower scores for sheep backfat cabanossi were within an acceptable range. Sheep backfat cabanossi were also scored for unique attributes that were not detected in the pork backfat cabanossi. This study concluded that fat-tailed sheep backfat can be used to produce an unique cabanossi product of acceptable quality.
- Full Text:
- Authors: Mahachi, Leo Nyikadzino
- Date: 2017
- Subjects: Fatty acids Lipids -- Oxidation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/6259 , vital:29530
- Description: The objective of this study was to determine the effect of different fat inclusion levels and fat types on the physical and chemical attributes, lipid oxidation, fatty acid composition and sensory characteristics of warthog cabanossi. To achieve this, three types of cabanossi with different pork backfat levels (10 percent, 20 percent and 30 percent) were produced for the first experiment. The results from the study showed that different inclusion levels of pork backfat had an influence (P ≤ 0.05) on the physicochemical and fatty acid composition of warthog cabanossi but did not influence lipid oxidation (P > 0.05). The highest (P ≤0.05) pH, weight and moisture decline was observed in the 10 percent pork backfat cabanossi compared to the 20 percent and 30 percent treatments. However, no differences (P > 0.05) in the water activity of the product were observed. As expected total fat was lower in the 10 percent fat treatment and increased concomitantly. Similarly, protein, ash and salt were higher in the 10 percent fat cabanossi and decreased concomitantly. Differences in the fatty acid composition were observed between treatments. Furthermore, backfat level affected the sensory attributes and consumer acceptance of the cabanossi. Ten percent backfat cabanossi was scored higher (P ≤0.05) for most sensory attributes. Consequently, it was observed that the consumer panel preferred and scored the 10 percent fat cabanossi higher with regards to appearance and taste. In the second experiment, two cabanossi treatments of different fat types (pork backfat and fat-tailed sheep backfat) were produced. The weight loss, moisture content, pH, water activity and salt content did not differ (P > 0.05) between the two cabanossi products. However, there were differences (P ≤0.05) in the protein, fat and ash contents; where protein and ash were higher in the pork backfat cabanossi whilst fat was higher in the sheep backfat cabanossi. Thiobarbituric reactive substances (TBARS) were similar (P > 0.05) between the two fat types cabanossi which could be explained by similar fatty acid profiles being reported for the two cabanossi although the n-6:n-3 ratio was higher (P ≤0.05) in sheep backfat cabanossi. Results from the descriptive sensory analysis showed two distinct products (P ≤0.01) where pork backfat cabanossi scored higher for most attributes. However, the lower scores for sheep backfat cabanossi were within an acceptable range. Sheep backfat cabanossi were also scored for unique attributes that were not detected in the pork backfat cabanossi. This study concluded that fat-tailed sheep backfat can be used to produce an unique cabanossi product of acceptable quality.
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Fatty acid composition, colour stability and lipid oxidation of mince produced from fresh and frozen/thawed fallow deer meat
- Authors: Chido, Chakanya
- Date: 2016
- Subjects: Lipids -- Oxidation Meat -- Preservation Mincemeat
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2479 , vital:27874
- Description: The aim of the study was to determine the fatty acid composition, colour stability and lipid oxidation of fresh mince produced from fallow deer and to evaluate the effect of frozen storage duration on the retail display shelf life of the mince. A total of 31 fallow deer carcasses were used in the study. After cooling for 24hrs, the carcasses were deboned, external fat from the fore and hindquarter muscles removed and individually vacuum packed. For the first trial, seven fallow deer carcasses were used. Meat from the hind and fore-quarters of each carcass was divided into two equal batches per animal. One batch was minced (through a 5 mm die) and packed into oxygen permeable overwraps and refrigerated at 4°C for a period of eight days under retail display conditions. The second batch was vacuum packed and frozen at -20°C for 2 months at the end of which mince was also produced and monitored over an eight-day period under the same conditions that were used for the fresh mince. Colour, pH, lipid and myoglobin stability was determined. Proximate and fatty acid composition was also determined. No differences (P>0.05) were noted between proximate composition of fresh and frozen/thawed minced meat. The lipid content of fallow deer was 2.4 percent (±0.04). Total n3 fatty acids differed (P<0.05) between treatments and decreased with increased storage and display day. There were significant (P<0.05) treatment and time interactions on all measured colour parameters, TBARS and myoglobin forms. Fresh mince was lighter and had higher redness (a*) and yellowness (b*) values than mince from two months frozen stored meat. Hue angle for fresh mince remained stable throughout display whereas it increased for frozen/thawed mince. Fresh mince had lower TBARS values than frozen/thawed mince. Minced meat produced from frozen/thawed deer meat had higher surface met-myoglobin and total met-myoglobin percentages. Surface and total oxy-myoglobin percentage was higher in fresh mince. The first trial clearly showed colour and lipid stability differences between fresh mince and mince from frozen/thawed meat. It also showed that fresh mince has a longer retail display life than mince produced from frozen/thawed meat (six days and four days, respectively). In the second trial, the effects of frozen storage duration on colour and lipid stability were investigated. Twenty-four fallow deer were used. Twelve were harvested in June (6male 6female) and the other twelve in August (6 male 6female) of the same year.Twenty four hours after harvesting, the fore and hindquarter muscles of the carcasses were deboned, vacuum packed and kept at -20°C until October (i.e. 2months and 4months frozen storage period). Upon thawing, the meat was processed into mince following the same procedure used for the first trialand displayed for a fiveday period under retail display conditions. Frozen duration and gender had no effect (P>0.05) on the proximate composition of fallow deer meat. The total amount of saturated fatty acids (SFA) increased and total amount of poly unsaturated fatty acids (PUFA) decreased as frozen duration and display day increased (P<0.05). Frozen duration affected (P<0.01) lipid oxidation and percentage oxy-myoglobin. Mince pH and all colour parameters (L*, a*, b*,hue and chroma) differed (P<0.05) between treatments on day zero and three. Display day was a significant factor (P<0.05) on all measured parameters. By day three all parameters except pH showed signs of extended oxidation and discolouration as evidenced by reduced redness, decreased colour intensity and high TBARS values. This study showed that prolonged frozen storage negatively affects the colour and lipid stability of meat and increases oxidation of PUFAs during frozen storage. However, the study also suggests that although frozen/thawed meat has a shorter retail display shelf life; the proximate composition of the meat remains unchanged.
- Full Text:
- Authors: Chido, Chakanya
- Date: 2016
- Subjects: Lipids -- Oxidation Meat -- Preservation Mincemeat
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2479 , vital:27874
- Description: The aim of the study was to determine the fatty acid composition, colour stability and lipid oxidation of fresh mince produced from fallow deer and to evaluate the effect of frozen storage duration on the retail display shelf life of the mince. A total of 31 fallow deer carcasses were used in the study. After cooling for 24hrs, the carcasses were deboned, external fat from the fore and hindquarter muscles removed and individually vacuum packed. For the first trial, seven fallow deer carcasses were used. Meat from the hind and fore-quarters of each carcass was divided into two equal batches per animal. One batch was minced (through a 5 mm die) and packed into oxygen permeable overwraps and refrigerated at 4°C for a period of eight days under retail display conditions. The second batch was vacuum packed and frozen at -20°C for 2 months at the end of which mince was also produced and monitored over an eight-day period under the same conditions that were used for the fresh mince. Colour, pH, lipid and myoglobin stability was determined. Proximate and fatty acid composition was also determined. No differences (P>0.05) were noted between proximate composition of fresh and frozen/thawed minced meat. The lipid content of fallow deer was 2.4 percent (±0.04). Total n3 fatty acids differed (P<0.05) between treatments and decreased with increased storage and display day. There were significant (P<0.05) treatment and time interactions on all measured colour parameters, TBARS and myoglobin forms. Fresh mince was lighter and had higher redness (a*) and yellowness (b*) values than mince from two months frozen stored meat. Hue angle for fresh mince remained stable throughout display whereas it increased for frozen/thawed mince. Fresh mince had lower TBARS values than frozen/thawed mince. Minced meat produced from frozen/thawed deer meat had higher surface met-myoglobin and total met-myoglobin percentages. Surface and total oxy-myoglobin percentage was higher in fresh mince. The first trial clearly showed colour and lipid stability differences between fresh mince and mince from frozen/thawed meat. It also showed that fresh mince has a longer retail display life than mince produced from frozen/thawed meat (six days and four days, respectively). In the second trial, the effects of frozen storage duration on colour and lipid stability were investigated. Twenty-four fallow deer were used. Twelve were harvested in June (6male 6female) and the other twelve in August (6 male 6female) of the same year.Twenty four hours after harvesting, the fore and hindquarter muscles of the carcasses were deboned, vacuum packed and kept at -20°C until October (i.e. 2months and 4months frozen storage period). Upon thawing, the meat was processed into mince following the same procedure used for the first trialand displayed for a fiveday period under retail display conditions. Frozen duration and gender had no effect (P>0.05) on the proximate composition of fallow deer meat. The total amount of saturated fatty acids (SFA) increased and total amount of poly unsaturated fatty acids (PUFA) decreased as frozen duration and display day increased (P<0.05). Frozen duration affected (P<0.01) lipid oxidation and percentage oxy-myoglobin. Mince pH and all colour parameters (L*, a*, b*,hue and chroma) differed (P<0.05) between treatments on day zero and three. Display day was a significant factor (P<0.05) on all measured parameters. By day three all parameters except pH showed signs of extended oxidation and discolouration as evidenced by reduced redness, decreased colour intensity and high TBARS values. This study showed that prolonged frozen storage negatively affects the colour and lipid stability of meat and increases oxidation of PUFAs during frozen storage. However, the study also suggests that although frozen/thawed meat has a shorter retail display shelf life; the proximate composition of the meat remains unchanged.
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The effect of grain and soya bean-based diets on chicken production, some egg quality traits, and the potential for allergen carryover to eggs and meat
- Authors: Dokora, Adia-En-Michelle
- Date: 2015
- Subjects: Chickens -- Nutrition Chickens --Feeding and feeds Meat -- Quality
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2946 , vital:28192
- Description: This study determined the effect of maize-, whole wheat-, soya bean-based-diets on the growth performance, egg quality and dressing percentage of chickens, as well as the potential for soy and gluten allergen carryover to eggs and meat from chickens. Twenty 36-week-old Lorham White (LW) hens were divided into two groups and kept in individual cages until they reached 39-weeks of age, with water and feed supplied ad libitum. Ten LW hens were fed a maize/soya bean-based diet (T1) and the other ten birds were fed a maize/soya bean-based diet with a 15 percent whole wheat inclusion (T2) for a period of four weeks, with weekly individual hen weights and group feed consumption figures being recorded. After a two-week diet adaptation period, six eggs per treatment group were collected every second day from the LW hens’ to measure egg quality traits. Every third day, over a 29-day period, six eggs per treatment were collected and analysed for the presence of soy, gluten and gluten-derived peptides using allergen specific enzyme linked immunosorbent assays (ELISA) kits. For the broiler trial, a total of 160 Ross 308 mixed sex day old chicks were used in a completely randomized design. Two dietary treatments were assigned to eight cages (replicate) per treatment, with ten birds per cage. The Ross 308 broiler feeding programme consisted of three phases, starter (day 1 to day 10), grower (day 11 to day 20) and finisher (day 21 to day 28). At the beginning of the trial all chicks were fed T1 which contained a maize/soya bean-based diet for a period of 10 days and then eight cages with 10 birds per cage were randomly selected and fed the T2 diet, which contained a maize/soya bean-based diet with a 15 percent whole wheat inclusion, until they reached 28 days of age. Weekly live weights, feed intake, average daily gain and the average daily feed intake were recorded and calculated. At the end of the grower (day 21) and finisher phase (day 28), one broiler bird was selected per cage to have eight (8) birds per treatment and 16 birds per phase that were slaughtered and breast meat samples were analysed in duplicate for the presence of soy and gluten allergens using ELISA kits. The dressing percentage of hot carcasses was also determined at the end of the finisher phase on eight birds per treatment. For LW hens, live weight (LW) at 39 weeks of age, the average daily feed intake (ADFI) and weekly feed intakes (FI) were significantly different (P < 0.05) between treatments with birds on T2 recording higher gains. As birds age in weeks increased, significant differences (P < 0.05) in live weight values were recorded. Egg quality traits measured (shell weight, yolk weight, albumen weight, albumen height and Haugh units) were significantly different (P < 0.05) between treatments, with eggs from hens receiving T1 recording higher mean values. As hens got older, the colour of egg yolk improved, producing eggs with higher b* (yellowness) values and lower L* (lightness) and a* (redness) mean values. The Haugh unit, significantly improved (P < 0.05) as the hens got older, signifying better quality of eggs. For the broiler birds, growth traits measured indicated that there were no significant differences (P > 0.05) in live weight (LW), average daily feed intake (ADFI), weekly feed intake (FI), feed conversion ratio (FCR), cumulative feed intake (CFI) and cumulative gain (CG) between treatments. No significant differences (P > 0.05) between dressing percentage of broilers from the two treatments were observed. As birds grew, significant differences (P < 0.05) in LW, FI, AFI, FCR, and CFI, over a four-week period were recorded. Results of the allergen analyses indicated that soy and gluten allergens were not carried over from feed into eggs and meat of chickens fed a maize/soya bean-based diet and a maize/soya bean-based with a 15 percent whole wheat inclusion, respectively. In conclusion, a maize/soya bean-based diet and maize/soya bean-based diet with a 15 percent whole wheat inclusion that contained soy and gluten allergens, are feed sources that promote and stimulate 36-week-old LW hen and Ross 308 chicken growth.
- Full Text:
- Authors: Dokora, Adia-En-Michelle
- Date: 2015
- Subjects: Chickens -- Nutrition Chickens --Feeding and feeds Meat -- Quality
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2946 , vital:28192
- Description: This study determined the effect of maize-, whole wheat-, soya bean-based-diets on the growth performance, egg quality and dressing percentage of chickens, as well as the potential for soy and gluten allergen carryover to eggs and meat from chickens. Twenty 36-week-old Lorham White (LW) hens were divided into two groups and kept in individual cages until they reached 39-weeks of age, with water and feed supplied ad libitum. Ten LW hens were fed a maize/soya bean-based diet (T1) and the other ten birds were fed a maize/soya bean-based diet with a 15 percent whole wheat inclusion (T2) for a period of four weeks, with weekly individual hen weights and group feed consumption figures being recorded. After a two-week diet adaptation period, six eggs per treatment group were collected every second day from the LW hens’ to measure egg quality traits. Every third day, over a 29-day period, six eggs per treatment were collected and analysed for the presence of soy, gluten and gluten-derived peptides using allergen specific enzyme linked immunosorbent assays (ELISA) kits. For the broiler trial, a total of 160 Ross 308 mixed sex day old chicks were used in a completely randomized design. Two dietary treatments were assigned to eight cages (replicate) per treatment, with ten birds per cage. The Ross 308 broiler feeding programme consisted of three phases, starter (day 1 to day 10), grower (day 11 to day 20) and finisher (day 21 to day 28). At the beginning of the trial all chicks were fed T1 which contained a maize/soya bean-based diet for a period of 10 days and then eight cages with 10 birds per cage were randomly selected and fed the T2 diet, which contained a maize/soya bean-based diet with a 15 percent whole wheat inclusion, until they reached 28 days of age. Weekly live weights, feed intake, average daily gain and the average daily feed intake were recorded and calculated. At the end of the grower (day 21) and finisher phase (day 28), one broiler bird was selected per cage to have eight (8) birds per treatment and 16 birds per phase that were slaughtered and breast meat samples were analysed in duplicate for the presence of soy and gluten allergens using ELISA kits. The dressing percentage of hot carcasses was also determined at the end of the finisher phase on eight birds per treatment. For LW hens, live weight (LW) at 39 weeks of age, the average daily feed intake (ADFI) and weekly feed intakes (FI) were significantly different (P < 0.05) between treatments with birds on T2 recording higher gains. As birds age in weeks increased, significant differences (P < 0.05) in live weight values were recorded. Egg quality traits measured (shell weight, yolk weight, albumen weight, albumen height and Haugh units) were significantly different (P < 0.05) between treatments, with eggs from hens receiving T1 recording higher mean values. As hens got older, the colour of egg yolk improved, producing eggs with higher b* (yellowness) values and lower L* (lightness) and a* (redness) mean values. The Haugh unit, significantly improved (P < 0.05) as the hens got older, signifying better quality of eggs. For the broiler birds, growth traits measured indicated that there were no significant differences (P > 0.05) in live weight (LW), average daily feed intake (ADFI), weekly feed intake (FI), feed conversion ratio (FCR), cumulative feed intake (CFI) and cumulative gain (CG) between treatments. No significant differences (P > 0.05) between dressing percentage of broilers from the two treatments were observed. As birds grew, significant differences (P < 0.05) in LW, FI, AFI, FCR, and CFI, over a four-week period were recorded. Results of the allergen analyses indicated that soy and gluten allergens were not carried over from feed into eggs and meat of chickens fed a maize/soya bean-based diet and a maize/soya bean-based with a 15 percent whole wheat inclusion, respectively. In conclusion, a maize/soya bean-based diet and maize/soya bean-based diet with a 15 percent whole wheat inclusion that contained soy and gluten allergens, are feed sources that promote and stimulate 36-week-old LW hen and Ross 308 chicken growth.
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