Evaluation of antioxidant activity of some plant extracts and their application to ground beef patties

Antioxidant properties and stability of aegle marmelos leaves extracts

Aegle marmelos (AM) leaves were extracted with methanol (ME), ethanol (EE), water (WE) and analyzed for antioxidant activities by DPPH radical scavenging method, reducing power and in vitro inhibition by Fenton's reagent-induced oxidation of lipid system. Stability of extracts to pH (4, 7 and 9) and temperature (100 °C, 15 min.) was studied. The three extracts showed varying degree of efficacy in each assay in a dose dependent manner. The inhibition of MDA formation in Linseed oil by EE (47%) was significantly (P < 0.05) higher than WE (28%) and ME (23%) but less than α- Tocopherol (80%). WE showed maximum stability to high temperature. The antioxidant activity of EE at pH 4 was significantly higher (P < 0.05) compared with WE and ME. At pH 7, the antioxidant activity of all the three extracts remained unchanged. Data indicates that potential exists for the utilization of Aegle marmelos as a natural antioxidant.

Antioxidant activity of spice extracts in a liposome system and in cooked pork patties and the possible mode of action

Three experiments were conducted to assess the antioxidant efficacy of spice extracts in cooked meat. In experiment 1, antioxidant activity of 13 common spice extracts was screened in a liposome system. Six of the extracts (clove, rosemary, cassia bark, liquorice, nutmeg, and round cardamom), identified to have the greatest total phenolic contents, were strongly inhibitory of TBARS formation. In experiment 2, 2,2-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, ferric-reducing power, and metal chelation of these six spice extracts were evaluated. Clove exhibited the greatest reducing power, and all had strong DPPH scavenging activity. In experiment 3, clove, rosemary, and cassia bark extracts were further tested for in situ antioxidant efficacy. Cooked pork patties containing these spice extracts had markedly reduced TBARS formation and off-flavour scores but a more stable red colour, during storage. The results demonstrated strong potential of spice extracts as natural antioxidants in cooked pork products.

Potato peel extract-a natural antioxidant for retarding lipid peroxidation in radiation processed lamb meat

The effective utilization of potato peel, a waste generated in large quantities by the food industry, as an antioxidant was investigated. Potato peel extract (PPE) exhibited high phenolic content (70.82 mg of catechin equivalent/100 g), chlorogenic acid (27.56 mg/100 g of sample) being the major component. The yield of total phenolics and chlorogenic acid increased by 26 and 60%, respectively, when the extract was prepared from gamma irradiated (150 Gy) potatoes. PPE showed excellent antioxidant activity as determined by beta-carotene bleaching and radical scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH). The suitability of PPE for controlling lipid oxidation of radiation processed lamb meat was also investigated. PPE (0.04%) when added to meat before radiation processing was found to retard lipid peroxidation of irradiated meat as measured by TBA number and carbonyl content. The antioxidant activity of PPE was found to be comparable to butylated hydroxytoluene (BHT).

[Studies of several analytical methods for antioxidant potential evaluation in food]

Oxidation control is necessary to manage the evolution of complex biological system, particularly in food whose degradation could have consequences on food security. After description of context and oxidation mechanisms, several analytical methods to evaluate the additive antioxidant potential are presented. This evaluation is performed either by quantification of products (in particular hydroperoxydes) using direct or indirect photometric techniques and chemical titration with suitable reactants or on the effectiveness to trap free radicals with modelized systems that can generate them. Methods based on the comparison of radical trapping ability between an additive and Trolox (particularly Trolox(R) equivalent antioxydant capacity, TEAC) can be applied to many products whatever the hydrophily or the hydrophobia of the medium.

Antioxidant evaluation in dessert spices compared with common food additives. Influence of irradiation procedure

The antioxidant properties of seven dessert spices (anise, cinnamon, ginger, licorice, mint, nutmeg, and vanilla) were compared with those of the common food antioxidants butylated hydroxyanisole (BHA) (E-320), butylated hydroxytoluene (BHT) (E-321), and propyl gallate (E-310). The influence of irradiation process on antioxidant activity was also evaluated. Mint and cinnamon exhibited a higher percentage of inhibition of oxidation than the other spices analyzed and the food antioxidants, as tested by the lipid peroxidation assay (LOO*). Nutmeg, anise, and licorice showed the strongest protection in the deoxyribose assay (OH*). Vanilla exhibited the highest antioxidant activity in the peroxidase-based assay (H2O2). Nutmeg, propyl gallate, ginger, and licorice improved the stability of oils (sunflower, corn, and olive) and fats (butter and margarine) against oxidation (110 degrees C Rancimat). Cinnamon was a better superoxide radical scavenger than the other analyzed spices and additives. When the Trolox equivalent antioxidant capacity (TEAC) assay was used to provide a ranking order of antioxidant activity, the result in decreasing order of antioxidant capacity was cinnamon approximately equal to propyl gallate > mint > anise > BHA > licorice approximately equal to vanilla > ginger > nutmeg > BHT. Irradiated samples did not show significant differences (p < 0.05) in the antioxidant activity with respect to the non-irradiated samples (1, 3, 5, and 10 kGy) in the assays used.