Abstract:
The cholesterol content (mg/100 g wet tissue) of the
longissimus dorsi muscle and the subcutaneous adipose
tissue of "Country Natural Beef" and regularly produced
beef was determined by a spectrophotometric method.
Proximate analysis (moisture, fat and protein contents) of
both types of beef was also determined.
Country Natural Beef (natural beef) is produced without
the use of hormones or antibiotic feed additives and with a
feedlot-finishing period of 50-85 days versus 120-150 days
for the regularly produced beef.
Samples of natural beef were taken from the 12th rib of
the right side of each carcass (N = 20) at 48 hr post
mortem. They were vacuum packaged, frozen and stored at
-20°C until analyzed. An equal number of regular beef (control) samples were obtained from a local food market.
The proximate analysis results show that the mean
moisture and protein contents of the natural beef muscle
(74.15% and 22.31%, respectively) were significantly
(P<0.001 and P<0.01, respectively) higher than those of the
control (71.56% and 21.02%, respectively). Conversely, the
mean muscle fat content of the natural beef (2.92%) was
significantly (P<0.01) lower than that of the control
(6.19%). For the adipose tissue, both moisture and fat
contents of the natural beef (11.21% and 83.40%,
respectively) were lower, but not significantly (P>0.05),
than those of the control beef (12.57% and 84.76%,
respectively).
Data of this study show that the difference between
mean muscle cholesterol content of the natural beef (56.91
mg/100 g) and the control beef (56.49 mg/100 g) was not
statistically significant (P>0.05). However, the
cholesterol content of the adipose tissue of the natural
beef (106.75 mg/100 g) was significantly (P<0.01) lower
than that of the control beef (113.08 mg/100 g). The
adipose tissue was found to contain nearly twice as much
cholesterol as the muscle tissue (overall mean values of
109.9 and 56.7 mg/100 g, respectively).
Even though the natural beef had an average
intramuscular fat content of 3% versus 6% for the control
beef, the mean cholesterol content of the natural beef muscle was almost identical to that for the control.
Although a reduction of feedlot-finishing days reduced the
intramuscular fat deposition in the natural beef, it did
not influence muscle cholesterol content.
