Alginate-based antibacterial biocomposite films were prepared by incorporating with cinnamon essential oil nanoemulsions (CEO-NE). CEO-NE was first prepared by mixing and homogenizing the oil phase and aqueous phase containing polysorbate 80 (Tween 80), using a probe-type ultrasonication equipment. The biocomposite films were then prepared by incorporating the CEO-NE to an aqueous solution of alginate and glycerol, homogenizing, casting, and drying. The mean droplet size, zeta potential, and polydispersity index of the CEO-NE were 92.2 nm, −15.58 mV, and 0.25, respectively. Young’s modulus of the CEO-NE/alginate biocomposite films was significantly increased with an increasing concentration of CEO-NE, while their elongation at break was significantly decreased. However, the tensile strength of the CEO-NE/alginate biocomposite films was not significantly changed. The maximum tensile strength and elongation at break of the biocomposite films were 15.63 MPa and 23.67%, respectively, corresponding to the biocomposite films containing 20% CEO-NE. The biocomposite films containing 20% CEO-NE also showed strong antibacterial effects against Salmonella typhimurium , Bacillus cereus , Escherichia coli , and Staphylococcus aureus , achieving inhibition zones from 29.7 to 53.0 mm. These results show the potential of the CEO-NE/alginate biocomposite films as antibacterial packaging for extending the shelf life of fresh foods.
The use of pesticides and veterinary drugs results in the appearance of residues of xenobiotics in foods. Thus, several methods have been developed for monitoring them; however, most are tedious and expensive. By contrast, the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) methodology involves a microextraction that yields small samples and has been applied for the analysis of various xenobiotics including pesticides, antibiotics, and mycotoxins. QuEChERS has shown advantages over other techniques including fast sample preparation, reduced needs for reagents and labware, and versatility. This approach allows the simultaneous determination of pesticides with various polarities and volatilities and can be easily modified for the analysis of a wide range of xenobiotics in various matrices including animal products rich in fat. Nevertheless, to attain high recoveries, the extraction, cleanup, and concentration steps have to be optimized according to the target compounds and matrix. Hence, QuEChERS is a promising and environmentally friendly methodology for the high-throughput routine analysis of xenobiotics in animal products. This review focuses on the application of QuEChERS to foods of animal origin and describes recent developments for the optimization of the analysis of veterinary drugs, pesticides, polycyclic aromatic hydrocarbons, and other compounds of concern.
Milk was co-fermented with Bacillus subtilis HA and Lactiplantibacillus plantarum EJ2014 to produce a dairy ingredient enriched with poly-γ-glutamic acid (γ-PGA) and γ-aminobutyric acid (GABA). The first fermentation of milk with B. subtilis HA resulted in a viscous broth with pH 6.56, 0.26% acidity, 1.40 mg/g tyrosine equivalent, and 17.21 U/g protease activity. The viable cell counts of B. subtilis indicated 8.74 log CFU/mL, and the consistency index of the alkaline fermented milk was 1.82 Pa·sn. In addition, 4.65% mucilage was produced with 35.93% γ-PGA content. The milk co-fermented by L. plantarum indicated 1.34% acidity and pH 4.91. The viable bacterial counts of B. subtilis decreased to 4.44 log CFU/mL, whereas those of L. plantarum increased to 9.42 log CFU/mL. Monosodium glutamate (MSG) as a precursor was effectively converted into γ-PGA by B. subtilis, and then residual MSG was completely converted into GABA by L. plantarum with a yield of 26.15 mg/g. Furthermore, the co-fermented milk produced volatiles, including hexanoic acid, 2,3-butanediol, and acetoin, which may be responsible for its aged cheese-like aroma.
1 January 2016 in Food Science and Technology Research