ABSTRACT
Nowadays, packaging research is receiving considerable attention because of the development of ecofriendly materials made from natural polymers such as starch and chitosan. This study aimed to prepare composite films from starch-chitosan, incorporated with Thymus vulgaris essential oil [S-CH-Th], and to evaluate their antibacterial, antioxidant and optical properties. The molecular weight of chitosan was [[tilde]400 kDa, 75-85% deacetylated]. 27% amylose corn starch, Tween 80, DPPH [2, 2-diphenyl-1-picrylhydrazyl] and Folin-Ciocalteu reagent were used to carry out research. Antibacterial activity testing was performed using the disk method. Antioxidant activity test was performed using a spectrophotometric method with DPPH as the radical source. Essential oil concentrations ranging from 0 to 2%, incorporated into a starch- chitosan composite [S-CH] film, were used. Antibacterial and antioxidant properties increased significantly with the incorporation of Essential oils [EO] [P < 0.05]. On incorporating EO, there was an increase in the total colour differences [DELTAE], yellowness index and whiteness index, which were significantly higher than those of the control, and the transparency was reduced. Also, the results showed that chitosan edible films incorporated with T. vulgaris EO could be used as active films because of their excellent antibacterial and antioxidant activities. S-CH edible films incorporated with thyme EO as a natural antibacterial and antioxidant agent may potentially be used as an active packaging to enhance the safety of foods and food products
ABSTRACT
Flavor is the crucial part of eating quality. In the preparation of natural identical flavor in different model systems like cysteine- ribose [cys-rib], cysteine-glucose [cys- glu] and cysteine-beef fat [cys-BF] affected at different pH [4.5, 7 and 10] a wide range of flavors was obtained. The proteins as glutamine, glutamic acid and the sugars as D- ribose and D-glucose,l,l-diphenyl-2-picrylhydrazyl [DPPH] and beta-Carotene and all the lab grade chemical as Linoleic acid, Polyoxyethylene sorbitan monopalmitate [Tween-80], Chloroform [99%], Anhydrous sodium sulfate, Dichloromethane [99.8%], 0.1 N HC1 and 0.1N NaOH, Gallic acid, Sodium carbonate, Folin-Ciocalteu reagent were used to conduct research. In sugar and amino acid model system, roasted and burnt meat flavor was obvious while in beef fat model system boiled meat flavor was dominated which was strongly supported by sensory evaluation. In rib-cys and glu-cys model systems total phenolic contents [TPC] were highest at pH 7 and pH 4.5, respectively along with browning, leading to strong antioxidant activity. In beef fat-cys model system it was found that as pH increases TPC, browning increases and antioxidant activity becomes maximum at basic pH. All the results indicated that, there is a positive relationship between the TPC, browning and antioxidant activity of all model systems
Subject(s)
Amino Acids , Carbohydrates , Food-Drug Interactions , Hydrogen-Ion Concentration , Antioxidants , Food Additives , Meat ProductsABSTRACT
This study was designed to examine the chemical compositions and antioxidant and antimicrobial activities ofessential oil, dichloromethane extract, and ethanol extract were prepared from fresh Schinus terebinthifolius leaves cultivated in Egypt. The essential oil was analyzed by gas chromatography and gas chromatography/mass spectrometry. The essential oil comprised 4.97% monoterpenes, 56.96% sesquiterpenes, 34.37% oxygenated monoterpenes, and 3.32% oxygenated sesquiterpenes. The major compounds in the essential oil were cis-beta-terpineol [GC peak area%, 17.87%], [E]-caryophyllene [17.56%], beta-cedrene [9.76%], and citronellal [7.03%]. The major phenolic compounds identified in the ethanol extract were caffeic acid [5.07 mg/100 mg extract], coumaric acid [1.64 mg], and syringic acid [1.59 mg]. The antioxidant activity of ethanol extract, which was comparable with that of butylhydroquinone, was superior to essential oil and dichloromethane extract in 2,2-diphenylpicrylhydrazyl and beta-carotene/bleaching assays. The dichloromethane extract exhibited the greatest antimicrobial activity against 6 strains, followed by the ethanol extract and the essential oil