Efecto conservante y antioxidante del aceite esencial de Origanum Vulgare y Rosmarinus Officinalis en chorizo Santandereano.

Abstract

The main objective of this research was to evaluate the effect of the addition of essential oil of Origanum vulgare and Rosmarinus officinalis on the conservation and oxidizing capacity of a Santanderean sausages, in order to consider its use as a natural preservative and antioxidant in foods. The extraction of the essential oil (EA) of the two species was carried out by microwave-assisted hydro-distillation. The oils obtained were analyzed in an Agilent Technologies GC-MS chromatograph, using a DB-5HT column and a temperature program that starts at 40°C up to a final temperature of 290°C in the laboratories of the University Research Headquarters (SIU) of the University of Antioquia. The minimum inhibitory concentration (MIC) of the oils was determined using a lyophilized strain of Salmonella typhimurium ATCC 140785, which was seeded through the agar diffusion technique (Müller Agar), sensidiscs (sterile filters) were inserted, with concentrations of 0.025% up to 50% of Rosemary and Oregano EO. The antioxidant activity of the essential oils was evaluated by measuring the 1.1-diphenyl-2-picryl hydracile radical catchment capacity (DPPH) and ORAC (Oxygen Radical Absorbance Capacity). Santanderean sausages were formulated and produced by implementing a randomized full block experimental design with three levels of Rosemary EO concentrations R1, R2 and R3 (0.025; 0.050 and 0.075%) and three levels of Oregano EO O1, O2 and O3 (0.0150; 0.200 and 0.390%), a T1 control level (0% nitrite and 0% EO), and a final T2 batch formulated with application of NaNO2 (200 ppm). The effect of the addition of essential oil of the two species on the inhibition of microbial activity in Salmonella typhimurium and Clostridium was determined in the sausages, oxidative stability tests were applied by determining the peroxide value (PV) and the content of substances reactive with 2-thiobarbituric acid (TBARS), pH tests and finally sensory tests were performed (satisfaction hedonic, flavor profile and texture). The results showed secondary metabolites belonging to the terpene family (Eucalyptol, α-pinene, camphor, caryophyllene and β-pinene for Rosemary EC and carvacrol, p-cymene, γ-terpinene and thymol for Oregano EC). Regarding the antioxidant activity measured by ORAC (hydrophilic and lipophilic) and DPPH methods, it was found that both oils have antioxidant capacity, being the Rosemary EC greater than the Oregano EC, likewise it was found that both oils present antimicrobial capacity in concentrations greater than 0.025% for the Rosemary EC and 0.200% for the Oregano EC. It was observed that the inoculation of Salmonella typhimurium in the sausages formulated with EO of Oregano and Rosemary in the different concentrations did not present growth, in the MacFarland scale 0.5 (Absent/25 g), but in the evaluated control samples (Presence/25 g). According to the analysis of VP and TBARS it was observed that the sausages whose formulation did not contain nitrites or AE (T1) showed formation of peroxides during the period between zero and twenty days; after this period they degraded presenting a decreasing tendency (after twenty days) and the perception of rancid odors. On the other hand, the nitrate salt added in the second formulation without EO (T2), made the tendency of VP to be upward during 42 days (no rancidity was presented) up to a value close to 3 milliequivalents of O2 per kg of fat. Rosemary and Oregano ECs formed peroxides during the 42 days of the test, finding values above the T1 formulation. Significant differences were found associated to the hydrogen potential, where all cases presented pH decrease between days (1, 8, 15 and 20) of storage. With respect to the hedonic test it was found that the best treatment in terms of appearance and odour attributes was the one that contained a concentration of 0.025% of Rosemary EC (R1), with a mean of 7.57 ± 1.06 and 7.83 ± 1.11 points respectively; as regards taste identified as the most relevant attribute, the T1 treatment was the best of 8.00 ± 1.54 points followed by the T2 treatment and the formulation with a concentration of 0.075% of Rosemary EC (R3) as the best treatments. Rosemary and Oregano essential oils; can be used as preservatives and antioxidants, however, the concentration applied can significantly alter the chemical (VP and TBARS) and sensory properties of the final product.