Impact of Natural Antioxidant Nanoemulsions on Oxidative Stability and Microbial Safety of Meat Products

Abstract

Meat products are highly nutrient dense foods that are vulnerable to loss in quality by lipid oxidation and microbial contamination which negatively affect the shelf life, safety and consumer acceptance of these products. As consumers tend to choose clean-label foods, the research focus has turned to finding natural preservatives instead of synthetic additives. However, using natural antioxidants and antimicrobials directly in meat matrices is hampered by a number of difficulties such as limited efficacy due to interactions with meat components, poor solubility and low bioavailability. The limitations are being overcome by the use of nanoemulsion technology, which delivers, protects and releases bioactive compounds with improved efficacy. The present review extensively discusses the effect of natural antioxidant nanoemulsions on the oxidative stability and microbial safety of meat products. The physicochemical principles involved in the formation, stabilization and functional ability of a nanoemulsion system with emphasis on the oil-in-water (o/w) system containing essential oils and plant-based bioactive ingredients are discussed. The mechanisms of action on lipid oxidation and pathogenic microorganisms are reviewed, and the importance of the nanometer scale size in membrane disruption and cellular penetration are emphasized. Various natural antioxidant nanoemulsions such as basil, clove, oregano, cinnamon and Zataria multiflora are discussed for their influence on the oxidative stability parameters, microbial safety indicators and sensory quality attributes. The quantitative data clearly show that nanoemulsion treatment can reduce the levels of lipid oxidation markers (30-60%) and the levels of microbial populations (1-2 log CFU/g). Efficacy factors such as formulation parameters, processing techniques and interaction with components of the meat matrix are considered. Regulatory issues, toxicity, scale-up and sensory concerns are critically assessed. Systematic assessment of safety, optimization of delivery systems and formulation of multi-functional formulations containing synergistic combinations of bioactive compounds are proposed as future research directions. Based on the evidence, nanoemulsion technology is considered a promising approach to meet consumer's demand for natural preservation for meat products.