Protein films with natural antioxidants decrease microbial growth in beef.Protein films create edible barriers that are environmentally friendly. High-fat-containing foods, such as beef, are easily subjected to lipid oxidation when they are stored. Protein films containing antioxidants extracted from food sources or edible natural products can improve the quality of foods by preventing lipid oxidation and the growth of bacteria. The objective of Korean scientists was to see how effective antioxidant protein films can be as a packaging system that would prevent lipid oxidation and improve the quality of beef during its storage. Zein zein the principal protein in maize. Has low nutritive value, being deficient in lysine and tryptophan. and soy protein isolate (SPI) film-forming solutions were prepared by dissolving zein and SPI in 95% ethanol and distilled water, respectively. This step was followed by heating and stirring the mixture. The scientists added glycerol glycerol, glycerin, glycerine, or 1,2,3-propanetriol (prō`pāntrī'ŏl), CH2OHCHOHCH2OH, colorless, odorless, sweet-tasting, syrupy liquid. as a plasticizer at 2.5%. Natural antioxidants, rosemary extract and isoflavone i·so·fla·vone n. A flavonoid found in soy. isoflavone 3-phenyl-4H-1-benzopyran-4-one; many of the naturally occurring estrogenic substances in pasture plants are isoflavones. , were added to the film-forming solution. Researchers cast and dried films that were peeled intact from the casting surface. Fresh beef samples were wrapped with each film and stored at 4 C for eight days. During storage, the researchers performed thiobarbituric acid-reactive substance (TBARS TBARS Thiobarbituric Acid Reactive Substances TBARS Tiberium-Based Armor Reinforcement Substance ) and microbial analysis of the samples. Zein film containing isoflavone had an 8.06 TBARS value after eight days of storage, compared with a 13.3 TBARS value for a non-packaged product and a 12.29 TBARS value for the film without the antioxidant. The result was a decrease of lipid oxidation by 35%. The SPI film containing the rosemary extract showed a decrease in lipid oxidation by 13%. Protein films containing antioxidants also inhibited the growth of total bacteria, including Salmonella and E. coli, by about one log cycle. These results show that protein films containing natural antioxidants decreased the amount of lipid oxidation that occurred in beef and deterred microbial growth during the storage of the product. Further information. K. B. Song, Department of Food Science and Technology, Chungnam National University Chungnam National University is one of national universities in Korea. History The Chungnam National University was established for South Chungcheong province in 1952 during the Korean War. , College of Agriculture and Life Sciences College of Agriculture and Life Sciences is the name of several colleges at different universities that offer instruction in agriculture and the life sciences.
in full Uniform Resource Locator Address of a resource on the Internet. The resource can be any type of file stored on a server, such as a Web page, a text file, a graphics file, or an application program. : www.chungnam.ac.kr. |
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