Evaluation of Eating Quality in Sensory Panelist and Instrumental Tenderness of Beef from Harar, Arsi and Bale Cattle Breeds in Oromia, Ethiopia

Meat is one of the most nutritious animal products that humans can consume, particularly in terms of supplying high-quality protein, minerals and essential vitamins. Hence, the demand for meat is not only quantity wise, but also quality wise. The objective of this study was evaluate eating qualities of beef produced at public abattoirs from Arsi, Bale and Harar cattle breeds with semi-trained sensory panel evaluation and instrumental tenderness. To know the status of meat produced for domestic market in relation with globally demands. The samples were collected from the longissimus dorsi region between 12th and 13th ribs within 45 min after slaughters. The samples were packed in vacuum-seal and aged for14 days to evaluate instrumental tenderness using Warner Bratzler Shear Force Device and eating quality using panel testing. Mean values of 33.12 N, 7.12, 7.2 and 7.24 were determined in instrumental tenderness, sensory tenderness, juiciness, and fl avor of beef respectively. The parameters were signifi cantly affected by age, breeds and season interactions (P<0.01). Breed interaction with age and season exhibited signifi cant variation (P<0.05) on water holding capacity. Beef pH was signifi cant affected by season. The instrumental tenderness had negative medium relationship with sensory attributes conducted for tenderness and juiciness, but positive with fl avor. From this study, it was concluded that quality of beef produced in study areas was relatively tender which internationally competent but becomes tough as cattle gets older. It is recommended that strategy should be developed to encourage premium payment for young cattle marketing that is not exposed to draft service and creating awareness among stakeholders on quality beef production. As Ethiopia is planning to in the beef market in the Middle East Countries, it is highly needed to promote Ethiopian beef at international markets. Research Article Evaluation of Eating Quality in Sensory Panelist and Instrumental Tenderness of Beef from Harar, Arsi and Bale Cattle Breeds in Oromia, Ethiopia Birmaduma Gadisa1*, Yesihak Yusuf2 and Mohammad Yousuf2 1Mechara Agricultural Research Center P. O. Box 19, Mechara, Ethiopia 2Haramaya University P.O. Box 138, Dire Dawa, Ethiopia Received: 18 February, 2019 Accepted: 14 May, 2019 Published: 15 May, 2019 *Corresponding author: Birmaduma Gadisa, Mechara Agricultural Research Center P. O. Box 19, Mechara, Ethiopia, Tel: +251910462545, +251986330181; E-mail:


Introduction
Ethiopia has long been recognized the center of origin of diverse livestock genetic resources in both Africa and the world at large [1]. However, livestock and its products are underutilized compared to its potential in Ethiopia [2]. The annual meat per capita consumption is 8.5 to 10 kg/year and annual milk per capita consumption is 19 litters/years [3]. Meat is one of the most nutritious animal products that humans can consume, particularly in terms of supplying high-quality protein (essential amino acids), minerals (iron) and essential vitamins [4]. Hence, the demand for meat is increasing not only quantity wise but also quality wise. Consumers satisfaction is primarily based eating quality [5,6].
The most important aspect of eating quality is the function of combined effects of tenderness, juiciness, fl avor, appearance and color. These eating qualities are affected by nutrition, slaughter ages, seasons, breeds, live weight, sexes, pre-and postmortem handling [7]. In particularly, tenderness has been linked to animal's age, marbling, muscle location and aging [8]. The older animals are the tougher meat source in general [9]. The greatest tenderness and quality of beef is achieved with cattle less than 36 months of age; thereafter the meat becomes tougher [10]. Marbling (intramuscular fat) is complex trait, which is obtained from many genes, because no single factor determines a large proportion of the trait variations in the population [11,12]. It rises from white fl ecks of fat within the meat muscle. Beef cuts with high levels of marbling are more likely to be tender, juicy and fl avorful than cuts with low levels of marbling [8].
However, mostly as age of cattle increased development of fat is increased fl avors [10]. The breed of animals for slaughter is one of the key factors determining the quality of meat. In recent years, feedlots are prosperous and being engaged in the export of processed meat and live animals in Ethiopia [13]. international and domestic beef consumption, especially for international market. Is there different eating quality across ages, breeds and seasons? These are the questions that need answer to properly utilize, plan to breed improvement and promote our resource for international market.
Seasonal variation affects the quality of beef cattle due to feed resources availability is closely relate with season of year [14]. Diet is the major factor infl uenced beef quality like sensory, physical and proximate composition [15]. Finishing diets changed ruminal biohydrogenation of polyunsaturated fatty acids without affecting the concentrations of conjugated linoleic acid in the meat. Various constituents in tissues are infl uenced by diet to affect fl avor, but the most important are the fatty [16].
Quality of beef is associated with stress. Animal can be stressed by improper pre-slaughter handling during transport and stunning that could result in undesirable pH, which causes for pale soft excuadative (PSE) and dark fi rm dry (DFD) meat, poor water-holding capacity and end up in poor cooking loss [17]. The DFD meat has a high ultimate pH, which exposes meat for high microbial contamination [18]. The high water-holding capacity of meat described as the ability of the post-mortem muscle to retain water.
Quality of meat can be analyzed through both instrumental and panel testing [19]. Only scant studies were conducted on eating quality of beef produced in Ethiopia using sensory panel testing. However, eating quality of beef using instrumental tenderness was not evaluated before in Ethiopia. The correlation between sensory evaluation and instrumental tenderness was not determined for Ethiopian cattle breeds. This study was design to investigate eating quality of beef produced at public abattoirs using trained sensory panelist and instrumental tenderness methods to evaluate PSE, DFD and water holding capacity (WHC) of beef from different breeds and ages of cattle slaughter for local consumption.

Meat samples collection and aging
In total 118 (48 during dry and 70 during wet season) samples were collected during dry and wet seasons from end of October to early November 2017 and mid to end June 2018, respectively. Daily slaughtered cattle were divided into age groups and breeds. Breeds and ages of cattle were deliberately selected. Breeds were identifi ed using the phenotypic traits in combinations of coat color, confi rmation, dewlap structure, ear, horn and hump type according to Rege and Tawah and DAGRIS [1,20]. The samples were collected from three breeds; Arsi, Bale, and Harar cattle. The Arsi and Bale breeds were collected from Adama city municipal abattoir while the samples from Harar breeds were collected from Haramaya community service abattoir. Age of cattle was determined using dentition according to Verifi cation Guidelines [21,22]. For purposive of this study the age was stratifi ed into four groups < 5, 5-7, 7-9, and > 9 years old.
The sample source cattle were tagged in the abattoir using simple random sampling technique before entering into lairage from 2 pm to 3 pm in Adama municipality abattoir. At Haramaya University, using phonotypical traits slaughtered cattle were given identifi cation number in hundred days staying barn prior upcoming to abattoir. The samples were collected during night time (10:00 pm to 4:00 am) from Adama abattoir and at morning (6-7 am), in Haramaya University. The samples were collected from specifi c location of longissimus-dorsi (LD) muscle between 12 th and 13 th ribs in abattoirs before rigor mortis.  Based on the criteria, twelve panelists were selected. The panelists' age was between 22 and 32 years old of both sexes.

Screening and training sensory panelists
The selected panelists were also checked for absence of meat allergies as well as a willingness to consume beef. Ten panelists participated directly while two were placed on reserve.

Steak preparation and sensory panelist testing
The samples were analyzed in batches. After 14 days aged samples were thawed for 24 hrs and steaks were prepared that have served for both sensory and instrumental tenderness evaluation. The steak preparation was done according to Warner-Bratzler Shear Force procedures protocol developed by AMSA [19]. Sensitive precision balance (power 2204/50Hz) model -yp10002 (China) were used for eight steaks before and after cooking. Cooking loss was calculated based on the following formula.

   
Initial weight -final weight Cooking loss calculate CL * 100 Initial weight  Sample presentation: Similar sample presentation procedures were conducted for all panelists at room temperature (24-25 o C) on metal pans plates with panelists receiving cuts from various locations. The steaks were cut uniformly to reduce any bias related to serving position and presented in white color plate randomly. Each assessor has evaluated three most important eating quality (tenderness, juiciness, and fl avor) parameters. The evaluators scored each sample on a 9-point hedonic scale for tenderness, fl avor, and juiciness. They were fi lled in three-digit of sensory codes, which indicated panelists codes, treatment codes, and sensory variables. Before actual testing, a warm-up sample was served fi rst, and then proceeded to experimental samples steak in the next testing sessions. Between each sample tasted, biscuit and clean water were served for calibration of the panelist taste [19].

Determination of instrumental tenderness
The steak was prepared based on the procedures of AMSA [19] and cooled at room temperature for one hour prior to determine tenderness by Warner Braztler Shear force (WBSF) apparatus as following: 1. After samples were cooled, connective tissue was removed across the long axis of the steak to expose the fi ber direction.
2. Six cores of 1.27 cm diameter were removed from each sample parallel with the muscle fi bers using of WBSF device.
3. The shear force was measured across the middle (center) on each core using WBSF value in kg for each core.

Determination of pH in Meat
The initial and fi nal pH of meat samples were measured after slaughter at 45 min and 24 hrs, respectively. This pH values was conducted using portable instrumental battery drive and glass electrodes digital pH meter. The pH meter probe was calibrated by inserting inserted into distilled water and a buffer solution, then touch a probe with meat and read the value of pH after about 30 seconds [26].

Statistical analysis
General leaner model (GLM) procedure of SAS 9.

Results and Discussion
Mean value of eating quality, WHC, pH, and cooking loss (CL) of beef samples are presented in table 1. The overall mean value of sensory panelists and WBSF (N) rated 7. 29, 7.16, 7.35, 42.94 N at the wet and 7.12, 7.23, 7.13 and 23.3 N at the dry season for sensory tenderness, juiciness, fl avor and instrumental tenderness of studied beef cattle, respectively. The mean value of WBSF for all beef cattle breeds evaluated in this study was equivalent to 33.12 N (7.51 lb). This indicated that the instrumental tenderness of meat in current fi nding were mainly tender (58.47% tender followed by 12.71% moderate and 28.81% tough beef) based on categories described by Calkines and Sulivan who grouped beef muscles into three tenderness groups. These were instrumental tenderness <37. 31 [27], who reported that shear force values for the Canchim (37.71 N) and Nellore (41.67 N) animals after seven days of aging (42.66 N) at zero days age of three beef cattle breed in Brazil. As Ethiopia is planning to in the beef market in the Middle East Countries, it is highly needed to promote Ethiopian beef at international markets.
The mean values of instrumental tenderness indicated that there were enormous difference between dry 23.3 N (tender) and wet season 42.94 N (intermediate). This might be due to good conformation of cattle during the onset dry season because of availability both quantity and quality feed resource, rest of draft cattle for a long time without physical work, less cold and warm weather stress. Farmer in mixed crop livestock system feed their bulls for sale on at the onset of dry season. In contrast to the general fact that cattle fatten well in wet season, particularly, short rainy, cattle were in poor body condition during this time in the study areas. During this short rainy season from March to June, cattle had passed sever long dry season (December to February), further emaciated due to stressed from physical work (ploughing) and loss their body condition. Bulls in mixed crop livestock system serve for draft purpose from March to June of the year. The current fi nding is in line with Pannier et al. [28], who report that energy source feed is used to activating Leptin protein production that regulates marbling and fat deposition.
The sensory panelist evaluation in current fi nding is comparable with Adhikari [29], on fl avor for prime meat cuts (7.42) and choice cuts (7.24) and tenderness for prime cuts (8.66). However, the fi gure in this fi ndings was good compared with Gebeyehu et al. [4], using trained sensory panelists rated (5.23) and (5.20) for beef tenderness and juiciness of Arsi cattle breed, respectively. Difference in sensory tenderness between the present fi ndings in the study from Arsi cattle breed might be due to postmortem aging and personal difference between The overall, mean value of WHC, initial pH, ultimate pH, and cooking loss were obtained 71.95, 6.55, 5.81, and 21.07 in the wet season and 73.82, 6.5, 5.62 and 9.99 in the dry season for beef of studied cattle, respectively. The result of WHC being low in wet than dry season might be due to lower WHC related lower body conformation in wet season than dry season in the present study. The overall mean cooking loss of current fi nding was comparable with the fi nding by Jama et al. [30], who reported that 23.9% cooking loss or Angus beef cattle at South Africa. It was better than report of Muchakilla et al. [31], which had reported 26.7% Tanzania Shorthorn Zebu for a different type of muscle and diet 26.97%. These differences might be due to cooking procedure, feeding region before slaughter and breeds difference.

Effects of breeds and age on sensory evaluation and instrumental tenderness
Effects of ages, breeds and seasons on beef eating quality and instrumental tenderness are presented in table 2. The analysis of variance indicated that breeds, ages and seasons interaction had highly signifi cant source of variation (P<0.01) on instrumental tenderness, juiciness and fl avor. The age interaction within breeds showed highly signifi cant (P<0.001) on juiciness, fl avor, sensory tenderness and instrumental tenderness. The body condition of beef cattle at end of wet season and beginning of dry season had good performance due to taking care of bulls by farmers in the region (September to December). This might be due to availability of good feeds and exposed to less physical work, however at entrance of wet season (February to May) scarcity of feed resource and exposed to the physical work might emaciate cattle, resulting in increased the value of instrumental tenderness, juiciness and sensory tenderness were shown in this fi nding.
The mean value of WBSF (N) had high signifi cant difference (P<0.001) on breeds type. Harar breed had good instrumental tenderness than Bale and Arsi breeds. This result might be due to the genetic or environmental difference or combination of two factors. As age of cattle increased value of instrumental, tenderness also increased. This might be due to the presence of more cross-link of collagen in older animal than younger once, which was less soluble during cooking. The current fi nding is in line with Guiusti et al. [27], who reported that younger animals produced tender meat with lower value of instrumental tenderness. The difference in result of instrumental tenderness across breeds might be as a result of expose to the different feed resource before slaughter. Harar breed at Haramaya University was managed in feedlots for few days. However, the others breeds were fi nished on roughage after being kept on extensive grazing system. The current fi nding is in line with the fi nding of Muchakilla et al. [31], who reported that beef from feedlot had the goods instrumental tenderness value compared to beef from grazing animals.
The ANOVA result indicated that age was shown strong signifi cant difference (P<0.001) on sensory tenderness. Breeds and seasons were not indicated statistically difference (P>0.05), on sensory tenderness, however, numerically the least square mean values were showed difference. In general, the numerical mean value of Harar breed had good tenderness than other breeds. Kerry and Ledward [32], reported that concentrate fed animals had produced more tender steak than forage-fed   [31], reported that natural pasture grazed animal had good aroma score than animal fi nished in feedlot.  [33]. The age had shown signifi cant difference (P<0.05) on WHC. As the age of the cattle increased, WHC also increased. This might be due to as animal gets older the sarcolemma was contracted and extracellular muscle was decreased (Calkins and Sullivan, 2006). This result was in line with Warner et al. [34], who reported that the water holding capacity of meat is infl uenced by genetic, age and pre-slaughter animal stress. The season had shown strong signifi cant difference (P< 0.001) on WHC. This happened due to cattle had different conformation at different season which commonly related to feed availability and exposed to physical work. This result was supported by Jorge and Rodrigo who reported that different feed types have a major infl uence on meat quality due to mainly affected animal conformation and fat content.

Effects of breeds and ages on water holding capacity, pH and cooking loss
The result of analysis variance indicated that ages, breeds and seasons interaction were not shown signifi cant difference (P>0.05) on initial pH. However, numerically least mean square value were showed different number on seasons, breeds and ages groups. Generally, the mean value of initial pH was increased as age of animal increased. This might be due to the better body condition of the young cattle at slaughter than aged once. This lower body condition implicated that lower energy reserve, which exposed them for faster exhaustion of glycogen consequently resulting in relatively lower initial pH [17]. The season had shown strong signifi cance difference on (P<0.001) on ultimate pH. This might be happened due to environmental difference made chronic stress on beef cattle during beginning of wet season due to passing through in long dry periods, water scarce and physical work [17].
The ANOVA results for ages, breeds and seasons interaction were indicated strong signifi cant difference (P<0.01) on cooking loss. This fi nding was indicated that cooking had decreased by ages of cattle. The decrease in cooking loss as aging increased was expected since enzymatic reactions by endogenous enzymes, such as collagenase, which are produced by bacterial within beef or by ionic solubilisation, progresses at faster rates aging increases. This might be also due to muscle (sarcomere) from a young animal was easily fragmented during cooking (Calkins and Sullivan, 2006). The current fi nding coincides with Jama et al. [30], who reported that endogenous enzymatic reactions, such as collagenase disintegrated the myofi brillar proteins and made connective tissue thereby improving cooking loss.

Conclusion
This study was conducted with the objective of evaluating eating quality of beef produced in wet and dry seasons at public abattoirs in Adama municipality and Haramaya University.
Sensory analysis was also conducted using trained panelists.
Warner Bratzler-Shear Force device was used to determine instrumental tenderness. The data were analyzed by using statistical software tools by SAS version (9.0). Recommendations to improve the quality of beef in Ethiopia. 1. Strategy that encourage premium payment for young cattle not served for draft purpose should be developed.

Breed improvement strategy should be developed for
Harar cattle breeds to produced tender meats.
3. Instrumental based quality evaluation technique will be more appropriate to evaluate beef in the future.
Further research work will need on: ✓ Investigate whether the eating quality difference between Harar, Arsi and Bale breeds was due to environment or genetics.