Mel e especiarias como protetores da oxidação lipídica em carne de frango / Honey and spices as protectors against lipid oxidation in chicken meat

RESUMO

Este estudo foi estruturado em cinco capítulos. No capítulo I temos um breve referencial teórico sobre a importância da carne de frango, os mecanismos da oxidação lipídica e a utilização de antioxidantes naturais. O capítulo II traz os ensaios da avaliação da atividade antioxidante in vitro do mel e das especiarias orégano (Origanum vulgare L.) e sálvia (Salvia officinalis L.) durante a vida de prateleira. Os resultados de fenólicos totais do orégano indicaram um aumento de 1154,09 a 1611,28 mgEAG/mL (O a 12 meses) e na sálvia os valores variaram entre 1309,8 a 2032,4 mgEAG/mL no decorrer do tempo (O a 12 meses). Os resultados da porcentagem da inibição da oxidação lipídica (% IOL), pelo sistemas β-caroteno/ácido linoléico mostrou que a sálvia inibiu a oxidação em 74,6, 81,3 e 81,3%, nos tempos (0,6 e 12 meses) e o orégano apresentou valores de inibição de (43,2, 63,3 e 50,7%). Quando se avaliou o índice de atividade antioxidante (IAA) utilizando o aparelho Rancimat, a sálvia apresentou um índice de atividade antioxidante (3,35) superior aos demais, que apresentaram 1,69, 1,25 e 1,08 para o BHT, orégano e mel, respectivamente. Os resultados do ensaio da capacidade de absorbância do radical oxigênio (ORAC) revelou que o orégano apresentou valores de 544,6, 430,7 e 1019,6 ET µmol/g, nos tempos O, 6 e 12 meses, respectivamente...

ABSTRACT

This study has been structured into five chapters. Chapter I provides a brief historical theoretical reference point regarding the importance of chicken meat, the mechanisms of lipid oxidation and the use of natural antioxidants. Chapter II presents trials evaluating the in vitro antioxidant activity, of honey and the spices oregano (Origanum vulgare L.) and sage (Salvia officinalis L.) over their shelf life. The results for oregano indicated an increase in total phenols from 1154.09 to 1611.28 mg of gallic acid equivalent (GAE)/100 g (0 to 12 months). For sage, the values changed from 1309.8 to 2032.4 mg GAE/100 g over the period (0 to 12 months) and for honey, the values measured were 1007.1, 1830.4 and 2129.9 mg GAE/100 g at the times of 0,6 and 12 months, respectively. The results relating to the percentage inhibition of lipid oxidation(% ILO) by the ß-carotene/linoleic acid system showed that sage inhibited oxidation by 74.6, 81.3 and 81.3% at the times of 0,6 and 12 months, while oregano presented inhibition values of 43.2, 63.3 and 50.7%. Evaluation of the antioxidant activity index (AAI) using the Rancimat apparatus showed that the AAI for sage (3.35) was greater than the indices for the other agents, which were 1.69, 1.25 and 1.08 for BHT, oregano and honey, respectively. The results from testing the oxygen radical absorbance capacity (ORAC) showed that oregano presented values of 544.6, 430.7 and 1019.6 TE µmol/g at the times of 0,6 and 12 months, respectively. Sage presented ORAC values of 610.45, 467.44 and 822.21 at the times of 0,6 and 12 months and honey presented 47.3, 22.4 and 26.1 ET µmol/g, at the times of 0,6 and 12 months. Comparing these results with those described in the literature, it can be concluded that these herbs and honey have high potential as antioxidants. Chapter III shows the influence of the bioactive compounds in sage and oregano for protection against lipid oxidation, in a microsomal substrate of chicken meat. The mean concentrations of TBARS (µmol of MDA/mg of protein) observed in the breast meat samples were, for the control, 7.45; for BHT, 1.91; and for oregano+sage, 3.45. In the thigh meat samples, the following results were observed control (9.83); BHT (4.27); oregano+sage (3.15). The treatments (BHT and oregano+sage) reached their peak inhibition after three hours (82.42% and 82.25%, respectively). However, analysis of the inhibition of lipid oxidation in the microsomal fraction of the thigh meat showed that the BHT treatment reached its peak inhibition (66.50%) after one hour of induction and the oregano+sage treatment reached its peak inhibition after three hours (82.25%). The results relating to inhibition of lipid oxidation during the induction period showed that, in relation to the control, the treatments implemented had a positive influence regarding protection against lipid oxidation in a microsomal substrate of chicken breast meat. Chapter IV evaluates the effect of spices and honey with regard to protecting against lipid oxidation in a system consisting of a homogenate model of chilled chicken meat. The results from water action on the breast and thigh meat homogenates (either, raw or cooked) showed that the treatment (oregano+sage+10%honey) reduced the quantity of free water over the period of refrigeration. With regard to the pH values in the breast meat homogenates, it was seen that they rose over the period of refrigeration, in all the treatments evaluated. In the thigh meat, the pH values were higher than those observed in the breast meat. In the homogenates of raw breast meat, a marked loss of moisture was observed in all of the treatments and, particularly, at all durations of refrigeration. In the samples of cooked breast meat, no significant differences in moisture were seen between the control and the treatment with oreganó+sage+5%honey. In the homogenates of raw thigh meat, the moisture values ranged from 60.82 to 66.96 g/100 g. The myoglobin content in the homogenates of raw breast meat ranged from 1.95% to 2.01% at time zero. After 96 hours of refrigeration, the percentage myoglobin ranged from 1.85 to 1.96, with lower concentrations in the samples treated with spices and honey...