INTRODUCTION
Protein is important for human beings and meat is known as the best source
of animal protein. The meat that is usually used for sources of protein is poultry,
beef, pork and mutton. In Malaysia, beef is the third largest source of meat
after poultry and pork (Ministry of Agriculture, 2009).
Besides being marketed in raw form, processed meat is also available in the
Malaysian market. Some processed meats that are popular among Malaysian people
are frankfurters, meatballs, nuggets and burgers. Beef meatballs, which in Malaysia
are called Bebola, are also popular in other countries with different local
names. They are called Bakso in Indonesia (Purnomo and Rahardiyan,
2008), Kung-Wan in Taiwan (Hsu and Chung, 2001),
Koefte in Turkey (Serdaroglu and Degirmencioglu, 2004),
Nem nuong in Vietnam (Legasse, 2009), Polpette in Italy
(Porrini et al., 1995), Kofta in India (Sarkar,
2009) and Konigsberger klopse in Germany (McGavin, 2009).
Beef meatballs are produced using a combination of salt, sugar and starch;
additives such as sodium polyphosphate and monosodium glutamate are also commonly
added because they can increase the water-binding and fat-emulsifying capacities
of the myofibrillar proteins and improve the taste of the products. Salt is
added in the processing to extract salt-soluble proteins, thus increasing the
binding, yield and juiciness of the product (Tseng et
al., 2000). Asian-style meatballs are commonly produced by emulsifying
fine ground meat with starch of some sort, mixing salt and certain herbs specific
to ethnic cuisine and finally shaping the product into balls. They are then
cooked in boiling water, steamed, or deep fried (Purnomo
and Rahardiyan, 2008). Asian-style meatballs are different from Western-style
meatballs, which are usually made from minced meat (Hsu
and Chung, 1998).
Texture is the most important characteristic influencing the quality of meatballs,
while color plays a minor role in product quality. Consumers prefer a hard texture
and a brightly colored product (Hsu and Chung, 1998;
Hsu and Yu, 1999). The texture or gel strength of chicken
meatballs increases with the addition of crude transglutaminase (TGase) (Tseng
et al., 2000). Early post-mortem meat used in beef meatball production
results in a more desirable texture (Purnomo and Rahardiyan,
2008). Higher salt addition causes more salt-soluble protein to be extracted,
which results in a harder final product (Hsu and Chung,
1998). Hsu and Yu (1999) reported that the addition
of 2.4% salt and 0.5% phosphate produced maximum texture scores that approximately
coincided with the maximal acceptance score. Decreasing the fat level resulted
in lower texture and overall palatability scores (Serdaroglu
and Degirmencioglu, 2004).
In terms of color, the increased addition of fat produced lighter products.
Salt was found to significantly decrease the product’s Hunter Lab value
(Hsu and Chung, 1998). Tapioca starch is a common starch
material for meatball production. The addition of lentil flour resulted in a
lighter product when compared to blackeye bean flour, chickpea flour or rusk
(Serdaroglu et al., 2005). The incorporation
of soya flour is not recommended in meatball production because lypoxygenase
enzymes that are released and activated after contact with water and oxygen
form ethyl-phenyl-ketones that has an unpleasant odor. Hsu
and Sun (2006) reported that pork meatballs made of soya bean products were
adhesive, viscous and brittle, but were low in sensory acceptance in terms of
odor and taste.
Recently, there has been a tendency for consuming convenience store food among consumers and beef meatballs have become one of the choices that fulfill consumers’ protein needs. In general, beef meatballs are high in protein and carbohydrate content, which are important macronutrients required by the human body. The purpose of this study was to determine the range of qualities and characteristics of commercial Malaysian beef meatballs.
MATERIALS AND METHODS
Sample Collection and Preparation
Six frozen samples of beef meatballs (A, B, C, D, E and F) were collected
from supermarkets located in the northern part of Malaysia and transported to
the laboratory in ice boxes. Each type of beef meatball came from a different
manufacturer. Two packets of each brand were picked randomly and analyzed. For
sample preparation, the frozen beef meatballs were thawed overnight at 4°C,
cooked in boiling water for 5 min and then cooled at room temperature.
Proximate and Mineral Composition
The proximate composition of the beef meatballs was determined according
to the AOAC (2000). The crude protein and crude lipid
contents were measured by Kjeldahl and Soxhlet methods, respectively. The ash
content was determined by ashing the samples overnight at 550°C. The moisture
content was determined by drying the samples overnight at 105°C and the
carbohydrate content was calculated by computing the difference. For mineral
determination, the samples were digested in 30% H2O2 and
65% HNO3. Ca and Na were measured using a flame atomic absorption
spectrophotometer (Perkin Elmer 3110, US).
Color Measurement
The color measurement was done based on the CIE (1978)
system color profile of lightness (L), while redness (a) and yellowness (b)
were measured by a reflectance colorimeter (Minolta Spectrophotometer CM-3500d,
Japan). The colorimeter was calibrated throughout the study using a standard
white ceramic tile.
Cooking Yield
Cooking yield was determined by measuring the difference in the sample weight
before and after cooking and was calculated according to Serdaroglu
(2006).
Folding Test
The folding test was conducted to analyze the gel strength of the cooked
beef meatballs and was determined according to Yu (1994).
Cooked samples were cut into 3 mm thick portions. The slices were held between
the thumb and the forefinger and folded to observe the way that they broke.
The scale used was as: (1) breaks by finger pressure, (2) cracks immediately
when folded in half, (3) cracks gradually when folded in half, (4) no cracks
showing after folding in half and (5) no cracks showing after folding.
Textural Measurements
The texture measurement on the meatballs was conducted with a computer-assisted
Stable Micro Systems TA-XT2i Texture Analyzer. The procedures for operating
the Texture Analyzer were stated in the Standard Operating Procedure (SOP).
The tests were carried out to compare the texture profile of meatballs obtained
from different tests. First, we conducted the Texture Profile Analysis (TPA),
which was used to determine hardness, cohesiveness, elasticity and chewiness
(Bourne, 1978). This test was carried out by using a
compression platen with a 75 mm diameter. The TA-XT2i setting for the TPA test
was: load cell 25 kg, pre-test speed = 2.0 mm sec-1, test speed =
2.0 mm sec-1, post-test speed = 5.0 mm sec-1, distance
= 50% and trigger type = Auto - 30 g.
Statistics
An analysis of variance was used to evaluate the data and significant differences
among the means were determined by the one-way ANOVA and Duncan’s multiple
test (p = 0.05) by using a computer based program of SPSS 11.5 for Windows.
Each analysis was replicated three times for proximate and mineral composition
and five times for color, cooking yield, folding test and textural measurement.
RESULTS
Labeling Information
Based on the products’ labels (Table 1), the main
ingredients used in Malaysian beef meatballs were quite similar. They include
beef, starch, sugar, salt, flavor enhancers and permitted food conditioners.
Information about the amount of meat that was used is not available. The types
of flavor enhancers and food conditioners that were used in the beef meatballs
usually were not clearly stated on the label. One of the meatball products (sample
F) did not have any labeling information. This product was normally produced
by small (home) manufacturers.
Proximate Composition
The proximate composition of a product mainly depends on the ingredients
used in its formulation. Different manufacturers produce different formulations.
Table 2 shows that there were significant differences (p<0.05)
in the proximate composition among the samples. The significant differences
(p<0.05) also show in the Na and Ca content of different brands of meatballs.
Color, Cooking Yield and Folding Test
Statistical analyses indicated that these values were significantly (p<0.05)
different among the beef meatballs from different manufacturers. All of the
beef meatballs did not show consistent changes after being subjected to cooking.
Some increased, while some decreased, in L and a and b values after cooking
(Table 3).
| Table 1: |
Ingredient information for the Malaysian commercial beef meatballs |
 |
|
| Table 2: |
Proximate composition and mineral content of Malaysian commercial
beef meatballs |
 |
| Data are Mean±SD (n = 6). Means with the same superscript
within the same column are not significantly different (p<0.05) |
| Table 3: |
Colour measurements, cooking yield and folding test scores
for Malaysian commercial beef meatballs |
 |
| Data are Mean±SD (n = 10). Means with the same superscript
within the same column are not significantly different (p<0.05) |
| Table 4: |
Textural properties of Malaysian commercial beef meatballs |
 |
| Data are mean±standard deviation (n = 10). Means with
the same superscript within the same column are not significantly different
(p<0.05) |
Textural Properties
The analysis revealed that there were significant differences (p<0.05)
in the textural properties of the samples (Table 4). For example,
Sample F had a high hardness value, cohesiveness ratio and chewiness value.
Samples A, B, C, D and E showed similar textural properties, especially in chewiness
(no significant difference at p<0.05).
DISCUSSION
Labeling Information
As for the main ingredients in the meatballs, the percentage of meat content
in the samples were not identified because such information was unavailable.
According to the Malaysian Food Regulation of 1985, Article 147 (Law
of Malaysia, 1996) states that manufactured meat that is prepared should
not contain less than 65% meat content. In addition, the regulation stated that
it should contain more than 1.7% nitrogen in organic combination. That regulation
also stated that manufactured meat is allowed to contain permitted preservatives,
coloring substances, flavoring substances, flavor enhancers and food conditioners.
The food conditioners that may be added to Malaysian manufactured meat products
are phosphate, ascorbic acid, sodium ascorbate, isoascorbic acid and sodium
isoascorbate. Most of the meatballs sample contains monosodium glutamate (MSG)
which is one of the permitted flavour enhancer.
Proximate Composition
The processing condition and the meatball formulation include cooking temperature
and ingredients such as salt, fat, sugar, polyphosphates and water that can
have significant effects on product qualities (Hsu and Chung,
1998; Hsu and Yu, 1999). Commercial beef meatballs
have a moisture content ranging from 63.25 to 73.78%. Similar results were reported
for Indonesian traditional meatballs with a moisture content that ranged from
69.52 to 71.17% (Purnomo and Rahardiyan, 2008). However,
the moisture content in the present samples was found high compared to Turkish-style
meatballs (koefte) that contained rice bran, which ranged from 58.13 to 66.82%
(Yilmaz, 2005), or with koefte that contained whey powder,
which ranged from 56.10 to 64.70% (Serdaroglu, 2006).
The protein content of commercial beef meatballs ranged from 7.39 to 12.51%.
This result was lower compared to the protein content of Indonesian meatballs,
which ranged from 13.38 to14.44% (Purnomo and Rahardiyan,
2008). Traditional koefte meatballs showed a higher protein content (25.51%)
(Ulu, 2004). Koefte meatballs prepared with different
levels of fat and flour also showed a higher protein content, ranging from 16.1
to 19.85% (Serdaroglu and Degirmencioglu, 2004). Pork
meatballs were also reported to have a higher protein content, ranging from
17.30 to 19.26% (Huang et al., 2005) and 25.51
to 29.85% (Ulu, 2004). Traditional Taiwan meatballs,
called Kung-Wang, showed a broad range of protein content ranging from 12 to
22% (Hsu and Yu, 1999).
The carbohydrate content showed an increase with a decrease in the protein
content. Commercial beef meatballs had carbohydrate contents that ranged from
8.02 to 25.86%. The addition of up to 25% of tapioca starch in meatball production
is still acceptable. This is because the incorporation of up to 50% of tapioca
starch still has acceptable sensory properties (Purnomo
and Rahardiyan, 2008).
The Malaysian Food Regulation of 1985 stated that manufactured meat should
not contain more than 30% fat. Malaysian beef meatballs can be classified as
low-fat meatballs since the fat content ranges from 1.69 to 11.09%. Low-fat
traditional Turkey koefte beef meatballs reported a similar fat content that
ranged from 7.9 to 8.8% (Serdaroglu et al., 2005),
which was lower than the normal traditional koefte with a fat content of 14.70%
(Ulu, 2004). Low-fat traditional Taiwan Kung-wan pork
meatballs also showed a similar fat content ranging from 6.69 to 8.63%, which
was lower than normal Kung-wans having a fat content of 17.51% (Hsu
and Sun, 2006). The lower fat content of commercial beef meatballs illustrates
the trend in the perception of Malaysian consumers on the negative effects of
high fat content and high cholesterol on health.
The ash content of Malaysian commercial beef meatballs ranged from 1.76 to
3.40%. Similar results were also reported by Serdaroglu
et al. (2005) on the ash content of koefte beef meatballs, which
ranged from 2.6 to 2.8%. However, an earlier report by Serdaroglu
and Degirmencioglu (2004) showed a slightly lower ash content in koefte
beef meatballs, ranging from 1.7 to 2.2%. The main source of ash, which is bone
and salt, is also added during meatball production. Salt is one of the processing
factors that has an influence on the quality of the meatballs (Hsu
and Chung, 1998). Normally, salt is added in amounts of 1.5 to 2.0% to extract
salt-soluble proteins and thus increase the binding, yield and juiciness of
the product (Tseng et al., 2000).
Meat and meat products are important for the human diet in many parts of the
world because they provide well- some of the essential elements (Demirezen
and Uruc, 2006). Calcium (Ca), an element useful for bone development and
growth and sodium (Na), part of the common formula for salt, are added during
meatball processing. There were significant differences in the Ca and Na contents
among the samples. There was also a large variation in the nutritional values
of commercial beef meatballs; the range of values for Na content included 585
mg/100 g, while the range of values for Ca content included 12.3 mg/100 g. Based
on these results, the Ca content of sample C and the Na content of sample B
were similar to the results obtained in the Turkey meatballs reported by Ferreira
et al. (2000), which were 7.57±0.70 and 688.34±23.78
mg/100 g, respectively. Turkey frankfurters showed higher Ca and Na contents
of 7.57±0.05 and 1327.11±33.09 mg/100 g, respectively. Since consumer
markets are demanding low-Na meat products, the partial replacement or the substitution
of salt with other binding agents to maintain or improve the quality of meat
products is desirable.
Color, Cooking Yield and the Folding Test
The color attributes of cooked meat products arise mainly from the pigmentation
of the meat from which they were made and the additives that were used in their
formulation (Serdaroglu, 2006). The lightness values
for samples A and F were similar to the results in meatballs containing wheat
flour, whey protein concentrate and soy protein isolate reported by Ulu
(2004), which ranged from 50.60-51.70. Other samples were slightly lighter
than pork meatballs (Huang et al., 2005), except
sample D. The values for the a (redness) in all the samples were similar to
the results reported by Yilmaz (2005). The yellowness
values of commercial beef meatballs were higher than those reported by Huang
et al. (2005), or with treated rice bran meatballs and wheat flour
of cooked meatballs reported by Ulu (2004).
Cooking yield is an important data that are used by the meat industry to predict
the behavior of their products during processing (Ulu, 2006).
The values of the cooking yield were similar to the results in high-fat Kung-Wan
meatballs reported by Huang et al. (2005), which
ranged from 101.57 to 103.84%, or in low-fat Kung-Wan meatballs reported by
Hsu and Sun (2006), which ranged from 98.04 to 102.19%.
The cooking yield of the Kung-wan significantly increased with higher salt levels
(Hsu and Sun, 2006). The meat also tended to shrink
during the cooking process due to the denaturation of meat protein; the loss
of water and fat also contributed to the shrinking process (Serdaroglu
et al., 2005).
The folding test was slightly different due to the different ingredients used
for each sample. A higher folding test can be reached with a washing treatment.
Yu (1994) reported that the double washing treatment
on fish meat enabled an increase in the folding score of the fish balls to 5.0
compared to 3.0 in the sample without the washing treatment. The washing treatment
will increase the ratio of myofibrillar protein to sarcoplasmic protein and
the higher degree of myofibrillar protein is essential for the formation of
protein networks during the cooking of meatball products.
Textural Properties
The hardness for all of the samples was higher compared to the veal meatballs
containing wheat flour, whey protein and soy protein isolate reported by Ulu
(2004), which ranged from 19.2 to 28.3 N. Kung-Wan meatballs containing
rice bran also showed a lower hardness value, which ranged from 17.18 to 26.88
N (Huang et al., 2005). According to Serdaroglu
et al. (2005), the factors responsible for the textural properties
in comminuted meat proteins are the degree of the extraction of myofibrillar
protein, stromal protein content, the degree of comminuting and the types and
levels of non-meat ingredients such as fat and starch. Increasing the fat content
of meatballs will lower their hardness values. Meatballs with a higher fat content
showed a lower hardness value (Ulu, 2004; Huang
et al., 2005). Starch or carbohydrate content also had an effect
on the hardness of beef meatballs. For example, Sample F showed higher hardness
values due to its high carbohydrate content (25.86%). The increase of the hardness
value is due to the increase of the carbohydrate content, which is also reported
by Huang et al. (2005).
The cohesiveness value of Malaysian beef meatballs was higher than the cohesiveness
value of veal meatballs reported by Ulu (2004), which
ranged from 0.38-0.43. However, this cohesiveness value was lower as compared
to the Kung-wan meatballs, which ranged from 0.78-0.81 (Huang
et al., 2005). Hsu and Chung (2001) reported
salt significantly increased product cohesiveness. Meatballs prepared by
Ulu (2004) had no salt, while meatballs prepared by Huang
et al. (2005) contained two percent salt. Salt is one of the ingredients
that is normally added during the production of meatballs in Malaysia and this
clearly explains the higher cohesiveness value compared to the reported by Ulu
(2004).
Malaysian beef meatballs showed a slightly higher springiness value compared
to veal meatballs, which ranged from 6.7-6.9 mm (Ulu, 2004)
or to the Kung-wan meatballs, which ranged from 9.4 to 9.5 mm (Huang
et al., 2005). According to Hsu and Yu (1999),
some processing factors that influenced the springiness or elasticity value
in low-fat Kung-Wan meatballs were salt and water; the springiness is also significantly
influenced by phosphates that are added during processing. Higher phosphate
levels significantly increased the cohesiveness, springiness and viscosity of
low-fat Kung-Wan meatballs.
A similar trend as for hardness value was also observed in the chewiness value.
Huang et al. (2005) stated a connection among
hardness, gumminess and chewiness, but springiness, adhesiveness and cohesiveness
showed no relation with hardness, gumminess or chewiness. The chewiness value
in Malaysian beef meatballs ranged from 40.48 N mm to 68.42 N mm. This value
is similar to the chewiness value of veal meatballs reported by Ulu
(2004), which ranged from 40.3 to 76.1 N mm.
CONCLUSION
In summary, the proximate composition, color and textural properties were generally
different among the different brands of beef meatballs. The moisture and protein
content of commercial beef meatballs ranged from 63.25 to 73.78% and 7.39 to
12.51%, respectively. The lightness and hardness value ranged from 47.73 to
58.79 and 56.66 to 82.20 N, respectively. The differences in the quality characteristics
of beef meatballs were mainly due to the difference in the formulation.
ACKNOWLEDGMENTS
The authors acknowledge with gratitude the support given by Universiti Sains Malaysia (USM) and the Malaysian Ministry of Science, Technology and Innovation (MOSTI) through Science Fund research grant 05-01-05-SF0089 and the aid of a research grant from Malayan Sugar Manufacturing Company Berhad for publication cost.
