Oxidative Stability of Frozen Pork Patties. Effect of Light and Added Salt

Impacts of different altitudes and natural drying times on lipolysis, lipid oxidation and flavour profile of traditional Tibetan yak jerky

The impact of different altitudes on the physicochemical properties, lipolysis, lipid oxidation, volatile compound formation and sensory evaluation of traditional Tibetan dried yak jerky during natural drying was investigated. High altitude (HA) yak jerky showed higher percentages of unsaturated fatty acids and thiobarbituric acid reactive substances than low altitude (LA) yak jerky during natural drying (P < 0.05). The percentages of polyunsaturated fatty acids and monounsaturated fatty acids decreased during natural drying, whereas that of saturated fatty acids increased (P < 0.05). A total of 54 volatile compounds were identified and quantified, and there were higher contents of volatile compounds in HA yak jerky than in LA jerky, which were mainly derived from lipid oxidation. Principal component analysis showed that the volatile compounds associated with the highest overall acceptability in HA yak jerky were hexanal, nonanal, (E)-2-nonenal, 1-hexanol, 2-heptanone, 2-methyl-3-octanone and 6-methyl-5-hepten-2-one. The volatile compounds associated with the highest overall acceptability for yak jerky with a longer natural drying time were hexane, 1-octanol, 2-ethylhexanol, heptanal, (E)-2-hexenal, (E)-2-octenal, 1-octen-3-ol and 2,3-octanedione. According to the sensory evaluations, HA yak jerky with a natural drying time of 75 d tends to be more popular.

Effect of Antioxidant and Antimicrobial Coating based on Whey Protein Nanofibrils with TiO₂ Nanotubes on the Quality and Shelf Life of Chilled Meat

Whey protein nanofibrils (WPNFs) can be used in edible films and coatings (EFCs) because of its favorable functional properties, which rely on its well-ordered β-sheet structures, high hydrophobicity, homogeneous structure, and antioxidant activity. In the present study, WPNF-based edible coatings with glycerol (Gly) as plastic and titanium dioxide nanotubes (TNTs) as antimicrobial agents were studied. TNTs not only showed greater antibacterial activity than titanium dioxide nanoparticles (TNPs), but also increased interactions with WPNFs. The WPNF/TNT film had a smooth and continuous surface and was homogeneous with good mechanical properties. WPNF/TNT edible coatings (ECs) can help improve lipid peroxidation and antioxidant activity, limit microbial growth, reduce weight loss, and extend the shelf life of chilled beef. Given that the WPNF/TNT film components are low cost and show high antioxidant and antimicrobial activity, these optimized films have potential applications for various food products, including raw and chilled meat.

Carbon Monoxide in Meat and Fish Packaging: Advantages and Limits

Due to increased demands for greater expectation in relation to quality, convenience, safety and extended shelf-life, combined with growing demand from retailers for cost-effective extensions of fresh muscle foods’ shelf-life, the food packaging industry quickly developed to meet these expectations. During the last few decades, modified atmosphere packaging (MAP) of foods has been a promising area of research, but much remains to be known regarding the use of unconventional gases such carbon monoxide (CO). The use of CO for meat and seafood packaging is not allowed in most countries due to the potential toxic effect, and its use is controversial in some countries. The commercial application of CO in food packaging was not then considered feasible because of possible environmental hazards for workers. CO has previously been reported to mask muscle foods’ spoilage, and this was the primary concern raised for the prohibition, as this may mislead consumers. This review was undertaken to present the most comprehensive and current overview of the widely-available, scattered information about the use of CO in the preservation of muscle foods. The advantages of CO and its industrial limits are presented and discussed. The most recent literature on the consumer safety issues related to the use of CO and consumer acceptance of CO especially in meat packaging systems were also discussed. Recommendations and future prospects were addressed for food industries, consumers and regulators on what would be a “best practice” in the use of CO in food packaging. All this promotes high ethical standards in commercial communications by means of effective regulation, for the benefit of consumers and businesses in the world, and this implies that industrialized countries and members of their regulatory agencies must develop a coherent and robust systems of regulation and control that can respond effectively to new challenges.

Myoglobin-induced lipid oxidation. A review

An overview of myoglobin-initiated lipid oxidation in simple model systems, muscle, and muscle-based foods is presented. The potential role of myoglobin spin and redox states in initiating lipid oxidation is reviewed. Proposed mechanisms for myoglobin-initiated lipid oxidation in muscle tissue (pH 7.4) and meat (pH 5.5) are evaluated with the purpose of putting forward general mechanisms explaining present observations regarding the catalytic events.

Acid-catalysed reduction of ferrylmyoglobin: product distribution and kinetics of autoreduction and reduction by NADH

The pH dependence of iron(II)/iron(III) product distribution, following reduction of the hypervalent iron in equine ferrylmyoglobin by the protein moiety of the pigment (so-called autoreduction) and by NADH (nicotinamide adenine dinucleotide, reduced) and the rate of reduction was found to depend different on pH. Autoreduction is specific acid catalysed and has a more modest temperature dependence than autoxidation of oxymyoglobin, with the activation parameters delta H# = 58.5 +/- 0.4 kJ.mol-1 and delta S# = 2.7 +/- 0.1 J.mol-1.K-1 in 0.16 mol.l-1 NaCl. The product of autoreduction is the iron(III) pigment metmyoglobin, which is slightly modified in the protein moiety. The reaction has a positive kinetic salt effect from which it is deduced that the reactive centre of ferrylmyoglobin has a charge of +1 in agreement with the structure Fe(IV) = O. Reduction by NADH involves parallel reactions of two pigment forms in acid/base equilibrium with each other with a pKa equal to 4.9, both forms yielding metmyoglobin as well as the iron(II) pigment, oxymyoglobin, as products. The protonated form reacts faster than the deprotonated form, and two-electron transfer has greater importance for the protonated form with a limiting Fe(II)/Fe(III) product ratio of 0.6 in acidic solution compared to 0.12 in alkaline solution. A square root dependence of rate on NADH concentration suggests involvement of NAD.radicals with a disproportionation as the termination reaction.