Interaction between microbial growth and lipid oxidation in ground beef /
Beef top rounds were ground and mixed with either water (non pretreated) or 60 ppm chlortetracycline and 0.2% potassium sorbate (pretreated). To each group was added sodium lactate (3%), sodium ascorbate (0.05%), sodium tripolyphosphate (0.5%), sodium citrate (0.5%), or water (for a control). Sample...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1994.
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| Summary: | Beef top rounds were ground and mixed with either water (non pretreated) or 60 ppm chlortetracycline and 0.2% potassium sorbate (pretreated). To each group was added sodium lactate (3%), sodium ascorbate (0.05%), sodium tripolyphosphate (0.5%), sodium citrate (0.5%), or water (for a control). Samples were aerobically packaged and stored at 4'C for up to 18 days.Aerobic plate counts (APCS) did not increase over storage in the pretreated group. In the non-pretreated group, only lactate acted as an antimicrobial agent. The pH of pretreated samples remained constant during storage, whereas that of the non-pretreated group rose, with the exception of lactate samples. Pretreated samples had higher 2-thiobarbituric acid (TBA) values than non-pretreated samples. Lactate tended to raise TBA values, especially in the non-pretreated samples. In contrast, ascorbate and citrate reduced TBA values irrespective of pretreatment. Unsaturation ratio (linoleic acid to stearic acid) decreased over time and correlated with TBA values, but it changed to a lesser extent than did TBA value. Fresh beef odor and soured off-odor scores were higher in pretreated samples, whereas overall off-odor and fruity off-odor scores were higher in nonpretreated samples. Ascorbate and citrate reduced overall off-odors in pretreated samples, and lactate reduced fruity off-odors in non-pretreated samples. Lactate and phosphate tended to increase soured off-odor in the nonpretreated group. Pretreated samples discolored more readily than non- pretreated ones. Lactate caused discoloration in the non- pretreated meat. Ascorbate and citrate protected red color, although the effect of citrate in the non-pretreated group was not statistically significant (P>0.05). Percent brown scores were also reduced by ascorbate. Slime scores were higher in non-pretreated samples, with lactate reducing slime formation in the non-pretreated meat. There apparently is an interaction between microbial growth and hpid oxidation. Although malonaldehyde may not be selectively utilized by bacteria, it does appear that bacteria can utilize the products of hpid oxidation. |
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| Item Description: | Vita. "Major subject: Food Science and Technology". |
| Physical Description: | x, 100 leaves : illustrations ; 28 cm. |
| Bibliography: | Includes bibliographical references. |