Analysis of phenolic antioxidant in some grain species grown in Turkey and natural extracts obtained by different methods of use in the food industry as a preservative in the food industry

ABSTRACT In our research, five different cereal growing in Agean zone (Turkish Amber Durum; Triticum turgidum L., Turkish red wheat; Triticum aestivum ssp.macha., Turkish hard white wheat; Triticum aestivum ssp.vavilovi., barley; Hordeum vulgare L. and barley-rye; Secale vulgare L.) were used and this cereal grains were germinated under same conditions. In this study, natural phenolic antioxidants in grass extracts obtained from natural resources rather than synthetic antioxidants will be detected Thus, elimination of the risks involved in the use of synthetic antioxidants in food safety is thought. In this way, we will also evaluate the cereal grass that is seen as more economical than synthetic antioxidants. For this purpose, extractions of dried and grounded cereal grass were studied by using water, ethanol and ethyl acetate as different solvents. Amount of extractable compounds from plants were found in the range of 21,66- 488,35 mg/g dried plant.The highest extraction yield were observed in water extraction. Antioxidant activities of the samples were determined by using different test methods, namely β-carotene/ linoleic acid, DPPH radical scavenging activity and H2O2 scavenging activity. The antioxidant activities of all extracts were assayed with the various methods including total phenolic content by Folin-Ciocalteu reagent (FCR) and their total flavonoid content were studied by using UV spectrometer. The obtained results were compared by using, ascorbic acid, BHT and BHA as standards. According to obtained results; all of extracts exhibited effective and high antioxidant activity. Antioxidant and antiradical activities of amber, white, red, wheat grass were found higher than barley and barley-rye grass. Chromatographic profile of phenolic compounds extracted from the sprouted cereals were detected. Phenolic compounds were analysed by comparing LC/MS-MS and HPLC systems and volatile compounds were detected by using GC-MS/MS system. According to LC-MS/MS and HPLC analysis results, ferulic acid, syringic acid, p-coumaric acid, vanillic acid, caffeic acid, gallic acid, ellagic acid, benzoic acid, quercetin, oleuropein, apigenin, luteolin, hydroxytyrosol, chlorogenic acid, were detected in all cereal grass but p-hydroxy benzoic acid were not observed. The main phenolic compounds of all cereal grass was ferulic acid. The most ferulic acid amount was detected in amber wheat grass (1305,8 mg/g dry basis). As pure phenolic compounds, ferulic acid, syringic acid, caffeic acid, sinapic acid were isolated from wheat bran and wheat germ by column chromatography, From these pure substances, benzyl esters of vanilic, syringic and caffeic acids were synthesized. Bromination of sinapic acid and acetylation of syringic acid were performed. These compounds structure were solved by melting point, IR, 1H NMR and 13C NMR. Antioxidant and antiradical activities of these synthesized compounds were compared according to pure phenolic compounds. In our research, to evaluate of protection of natural food on cereal grass extracts, hot water extracts of cereal grasses were prepared. These extracts were added to meat patties of sheep and goat which were grown in Manisa- Demirci. Lipid oxidation and the color properties, pH, peroxide and TBA value, color value and sensorial properties of these patties were examined during storage at +4 and -20 0C degrees. While amber, red and white wheat grass extracts showing the highest antioxidant effect, antioxidant effects of barley and barley- rye extracts were lower than these. These results revealed that, the addition of hot water extracts obtained from red, white and amber wheat, barley and barley-rye grass leaves in 0,2 percent to sheep and goat patties at – 20°C and 4°C storage degrees prevents development of oxidative processes in lipids and also changes in color. Keywords: cereal grass, antioxidants, phenolic compounds, extractions methods, free radical scavenging activity,natural antioxidant, color stability, lipid oxidation