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Studies on factors affecting beef taste and the effects of dietary glycerin on growth performance and carcass characteristics in Korean cattle steers

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dc.contributor.advisor백명기-
dc.contributor.author박민우-
dc.date.accessioned2018-05-28T16:34:45Z-
dc.date.available2018-05-28T16:34:45Z-
dc.date.issued2018-02-
dc.identifier.other000000149931-
dc.identifier.urihttps://hdl.handle.net/10371/140796-
dc.description학위논문 (박사)-- 서울대학교 대학원 : 농업생명과학대학 농생명공학부, 2018. 2. 백명기.-
dc.description.abstractBeef marbling score and quality grade positively affect meat sensory characteristics, including tenderness, juiciness, flavor, and overall palatability. Korean cattle beef is well known for good palatability because of the high quality grade and thus high marbling. Limited information is available and variability exists in data on the associations among marbling score/quality grade, meat characteristics, and sensory traits in Korean cattle beef. Korean consumers prefer Korean cattle beef to domestic Holstein and imported beef because they believe that the palatability of Korean cattle beef is superior to that of other breeds. Limited information is available on the factors that affect the preference of Korean consumers for Korean cattle beef over other breeds. Two studies (study 1 and 2) were conducted to elucidate 1) the associations among quality grade/marbling and various carcass characteristics and sensory traits in Korean cattle beef, and 2) the factors that contribute to differences in the sensory traits of longissimus thoracis of different breeds.
Glycerol, a by-product with biodiesel, also known as glycerin, serves as gluconeogenic substrate in the liver and kidney, and it has an energy value similar to corn on a pound-for-pound basis in dairy and feedlot cattle. Although many studies were conducted for the effect of glycerin on carcass composition and characteristics in various animal diets, the outcomes were not consistent. Also, limited information is available for effects of glycerin supplementation on meat characteristics in Korean cattle steers. Two studies (study 3 and 4) were conducted to identify 3) the effects of dietary glycerin replacement on growth performance, carcass characteristics and sensory traits in Korean cattle steers fed diets based on the similar TDN level between experimental diets, and 4) the effects of crude glycerin supplementation on growth performance and carcass characteristics in Korean cattle steers fed diets based on the different TDN level between experimental diets.

1. Comparison of carcass and sensory traits, fatty acid profiles and volatile compounds among quality grades in longissimus dorsi and semimembranosus muscles of Korean cattle steer
This study was performed to compare carcass traits, sensory characteristics, physicochemical composition, nucleotides and collagen content, free amino acids, content and composition of fatty acids (FA), and volatile compounds among four quality grades (QG1++, 1+, 1, and 2), and to understand their association with carcass characteristics in longissimus dorsi (loin) and semimembranosus (rump) cuts of Korean cattle steers. This study confirms that marbling score (MS) and intramuscular fat (IMF) content are major positive determinants of QG in Korean cattle beef. Numeric values of tenderness, juiciness, and overall acceptability in loin tended to be highest in QG1++, and those of juiciness and overall acceptability tended to be lowest in QG 2. Juiciness and overall acceptability were strongly correlated with QG. Our results demonstrated that QGs are linked to sensory traits. However, the nucleotide contents including inosine monophosphate (IMP) may not be major factors determining meat palatability of Korean cattle beef in this study. Glutamic acid and proline were significantly associated with tenderness, juiciness, and overall acceptability, although they did not differ significantly among QGs. In addition, beef QGs affected the compositions and contents of FAs and volatile compounds in loin and rump. Loin FA percentages, especially those of oleic acid (C18:1n9) and monounsaturated FA (MUFA), generally increased with increasing QGs. Some volatile compounds in loin and rump varied with QGs and were positively or negatively correlated with flavor.

2. Comparison of reducing sugar content, sensory traits, and fatty acids and volatile compound profiles of longissimus thoracis among Korean cattle, Holsteins, and Angus steers
This study was performed to compare intramuscular fat (IMF) and reducing sugar contents, sensory traits, and fatty acid (FA) and volatile compound profiles in longissimus thoracis (LT) among Korean cattle (KC), Holstein (HO), and Angus (AN) steers. The IMF, reducing sugar content, and sensory traits of the LT varied among KC, HO, and AN steers. The KC LT had the highest IMF and reducing sugar contents, and the best sensory traits (flavor, tenderness, juiciness, and overall acceptance). The IMF and reducing sugar contents were positively correlated with all of the sensory traits, suggesting that these factors may positively affect beef flavor. Palmitic acid (C16:0), oleic acid (C18:1n9), and monounsaturated FA (MUFA) may positively affect sensory traits, whereas linoleic acid (C18:2), and polyunsaturated FA (PUFA) may negatively affect sensory traits. The percentages of different volatile compounds in the LT also varied among the three breeds. The KC had the highest percentage of volatile compounds, including acetaldehyde, 3-methyl butanal, and 3-hydroxy-2-butanone, and these compounds were positively correlated with flavor. Our results demonstrated that variations in IMF, reducing sugar content, and FA and volatile compound profiles may contribute to differences in the sensory characteristics of the LT among breeds. The results of this study enhance our understanding of the association of reducing sugar and volatile compound contents with the sensory traits of beef. This information may help in determining beef palatability.

3. Effects of dietary glycerin replacement on growth performance and rumen and carcass characteristics in Korean cattle steers
The study was performed to evaluate the effect of 3% dietary glycerin replacement on growth performance, blood metabolites, ruminal fermentation characteristics, carcass characteristics and sensory traits, hepatic gluconeogenic gene expression, and muscle glycogen contents in Korean cattle steers. Glycerin replacement in the finishing diet of Korean cattle steers had no impact on weight gain, average daily gain, and feed efficiency except for increase in average daily concentrate intake. This increased intake may be attributed to the sweet taste of glycerins property. Glycerin replacement did not affect carcass characteristics, chemical and physico-chemical composition, reducing sugar, glycogen, collagen, nucleotides, fatty acid, volatile compounds, and sensory traits in the longissimus thoracis. These results indicate that the glycerin inclusion level (3%) may be not enough to improve animal performance and carcass characteristics. In addition, feeding concentrate containing 3% of glycerin did not result in detrimental effects on growth performance, ruminal fermentation, animals physical condition, and metabolism. This is important not only on animal performance and carcass characteristics but also for sustainable and economic aspects because glycerin is a biodiesel residue and it can potentially partially replace some expensive ingredients such as corn, molasses, distillers dried grains with solubles as an energy source for beef cattle.

4. Effect of dietary crude glycerin supplementation on performance, blood metabolites, ruminal fermentation parameters, and carcass characteristics in Korean cattle steers
This study was performed to evaluate the effect of dietary glycerin supplementation on growth performance, blood metabolites, ruminal fermentation characteristics, carcass characteristics and sensory traits, glycogen content in liver and muscle, and hepatic gluconeogenesis gene expression in Korean cattle steers finished in feedlot. This study confirms that dietary glycerin supplementation at 6.4% of DM did not lead to detrimental effect on feed intake in Korean cattle steers. Both glycerin and corn starch supplementation did not improve average daily gain and feed efficiency in Korean cattle steers. Glycerin supplementation also did not affect rumen fermentation characteristics, carcass characteristics, IMF content, reducing sugar content, glycogen content in both liver and muscle, and sensory traits of Korean cattle steers. Both glycerin and corn starch supplementation did not affect serum glucose concentration at initial and 8th week, but glycerin supplementation slightly increased the average serum glucose concentration at 16th week. Although glycerin supplementation had no impact on carcass and meat quality, glycerin could be potentially considered as a good energy source to maintain the animals metabolism in finishing Korean cattle.
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dc.description.tableofcontentsCHAPTER ONE 1
GENERAL INTRODUCTION 1

CHAPTER TWO 4
LITERATURE REVIEW 4
1. Overview of Korean cattle 4
1) History of Korean cattle 4
2) Korean cattle industry 5
3) Beef quality grading system in Korea 7
4) Characteristics of Korean cattle beef 8
2. Factors affecting sensory traits 12
1) Tenderness 12
2) Flavor 13
3) Juiciness 17
4) Precursors of flavor 17
3. Glycerin as feedstuff 20
1) Properties of glycerol 21
2) Glycerol as energy source 22
3) Glycerol fermentation in rumen 25
4) Glycerol metabolism in ruminants 28
5) Effect of glycerol on carcass characteristics and sensory traits 30
4. References 33

CHAPTER THREE 43
Comparison of carcass and sensory traits, fatty acid profiles and volatile compounds among quality grades in longissimus dorsi and semimembranosus muscles of Korean cattle steers 43
1. Abstract 43
2. Introduction 45
3. Materials and methods 49
3.1. Animals and sampling 49
3.2. Proximate composition, cooking loss, shear force, pH, and color 53
3.3. Nucleotide content 53
3.4. Total and insoluble collagen contents 54
3.5. Free amino acids 55
3.6. Sensory evaluation 56
3.7. Fatty acid composition 57
3.8. Volatile compounds 58
3.9. Statistical analysis 60
4. Results and discussion 60
5. Conclusion 119
6. References 120

CHAPTER FOUR 127
Comparison of reducing sugar content, sensory traits, and fatty acids and volatile compound profiles of longissimus thoracis among Korean cattle, Holsteins, and Angus steers 127
1. Abstract 127
2. Introduction 128
3. Materials and methods 130
3.1. Beef sample preparation 130
3.2. Proximate composition, color, pH, shear force, and collagen content 133
3.3. Reducing sugars 133
3.4. Sensory evaluation 134
3.5. Fatty acid composition 135
3.6. Volatile compounds 136
3.7. Statistical analysis 137
4. Results and discussion 138
5. Conclusion 164
6. References 165

CHAPTER FIVE 169
Effects of dietary glycerin replacement on growth performance and rumen and carcass characteristics in Korean cattle steers 169
1. Abstract 169
2. Introduction 170
3. Materials and methods 173
3.1. Animals, housing, and diets 173
3.2. Blood, rumen fluid collections and measurements 177
3.3. Slaughter procedures and tissue sample collections 178
3.4. mRNA level in the liver 180
3.5. Chemical and physicochemical composition, color, pH, and shear force 181
3.6. Reducing sugar content 181
3.7. Sensory evaluation 181
3.8. Glycogen concentration 181
3.9. Fatty acid profile 182
3.10. Volatile compound 183
3.11. Statistical analysis 183
4. Results and discussion 184
5. Conclusion 208
6. References 209
CHAPTER SIX 215
Effect of dietary crude glycerin supplementation on growth performance, blood metabolites, ruminal fermentation parameters, and carcass characteristics in Korean cattle steers 215
1. Abstract 215
2. Introduction 216
3. Materials and methods 219
3.1. Animals, housing, and diets 219
3.2. Blood, rumen fluid collections and measurements 222
3.3. Slaughter procedures and tissue sample collections 223
3.4. mRNA level in the liver 225
3.5. Chemical and physicochemical compositions, color, pH, shear force, and water holding capacity 225
3.6. Reducing sugar content 226
3.7. Sensory evaluation 226
3.8. Glycogen concentration 226
3.9. Statistical analysis 226
4. Results and discussion 227
5. Conclusion 248
6. References 249

CHAPTER SEVEN 254
General conclusion 254

SUMMARY IN KOREAN 259
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dc.formatapplication/pdf-
dc.format.extent1825353 bytes-
dc.format.mediumapplication/pdf-
dc.language.isoen-
dc.publisher서울대학교 대학원-
dc.subjectKorean cattle steers-
dc.subjectquality grade-
dc.subjectcarcass traits-
dc.subjectloin-
dc.subjectrump-
dc.subjectfatty acid-
dc.subjectvolatile compounds-
dc.subjectintramuscular fat-
dc.subjectsensory traits-
dc.subjectreducing sugar-
dc.subjectglycerin-
dc.subject.ddc630-
dc.titleStudies on factors affecting beef taste and the effects of dietary glycerin on growth performance and carcass characteristics in Korean cattle steers-
dc.typeThesis-
dc.description.degreeDoctor-
dc.contributor.affiliation농업생명과학대학 농생명공학부-
dc.date.awarded2018-02-
Appears in Collections:
College of Agriculture and Life Sciences (농업생명과학대학)Dept. of Agricultural Biotechnology (농생명공학부)Theses (Ph.D. / Sc.D._농생명공학부)
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