Oxidative stability and texture of meat as affected by salts and haem pigments

Wettasinghe, Mahinda (1995) Oxidative stability and texture of meat as affected by salts and haem pigments. Masters thesis, Memorial University of Newfoundland.

[English] PDF (Migrated (PDF/A Conversion) from original format: (application/pdf)) - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (5MB) [English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. (Original Version)

Abstract

Due to concerns over the role of nitrite and high sodium chloride concentrations in cured meat products, nitrite-free alternative meat curing systems consisting of a colorant, the pre-formed cooked cured-meat pigment (CCMP) and antioxidant/chelator mixtures with or without an antimicrobial agent and other usual curing adjuncts have been developed. The present study was conducted to examine the antioxidative efficacy of CCMP (at 2.2, 6.2 and 10 μM), alone or in combination with sodium ascorbate (SA) and/or sodium tripolyphosphate (STPP), in a β-carotene/linoleate model system. For comparative properties, pro- or anti-oxidative effects of metmyoglobin (MMb), nitrosylmyoglobin (NOMb) and butylated hydroxyanisole (BHA), were also investigated in the same model system at the same concentrations. CCMP exhibited an antioxidative effect at 6.2 and 10 μM concentrations and its activity was greater than that of NOMb, but less than that of BHA, whereas MMb exhibited a prooxidative effect. Moreover, the antioxidative properties of CCMP in the presence of both SA and STPP (at 550 and 500 ppm, respectively) was marginally enhanced when compared to that of CCMP alone. -- Sodium chloride, generally regarded as a prooxidant, is always used in curing mixtures. In order to investigate whether this prooxidant effect as well as the influence of salt on water-binding capacity (WBC) and texture originates from the sodium ion or the chloride ion of the molecule, a number of halides and sulphates of alkali and alkali-earth metals (at 100 and 200 meq/kg meat) were examined in a meat model system. Similar studies were carried out using Pan®-salt (52% NaC1 + 28% KC1 + 12% MgSO₄ + 3% Lysine.HC1), a commercially-available low-sodium salt, at 1, 2 and 3%. Results were compared with those for 1, 2 and 3% NaC1. Lipid oxidation was monitored over a 7-day storage period at 4°C using the 2-thiobarbituric acid-reactive substances (TBARS) test. For systems exhibiting an antioxidative effect, further studies were carried out to determine their content of hexanal. Furthermore, salts with antioxidant activity were tested in a β-carotene/linoleate model system. Fluorides and iodides of alkali metals inhibited lipid oxidation in meat model systems as reflected in TBARS values and hexanal contents and in a β-carotene/linoleate model system. Meanwhile, chloride and bromide salts of alkali and alkali-earth metals had generally a minor prooxidative influence on lipid oxidation in both systems examined. Fluorides of alkali-earth metals did not exhibit an antioxidant activity, presumably due to an ion-pairing mechanism, while their iodide analogues remained effective. Pan®-salt showed a slight prooxidative effect in meat model systems similar to that of NaC1. -- Halides and sulphates of alkali and alkali-earth metals (except MgF₂, MgBr₂, MgI₂ and CaF₂) increased the cook yield (ie., WBC) of treated samples whereas most salts (except LiF, NaF and LiCl) imparted a firm texture (ie., high shear force values) to meat. The effect of Pan®-salt on increasing the cook yield and improving the texture of meat was generally less than that of NaCl at the same concentrations examined.

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