No abstract

Using corn starch (CS) and κ-carrageenan(κC) as the raw material and active composite, respectively, films containing different concentrations of ethanol extract of onion skin were prepared. The effects of different concentrations of ethanol extract of onion skin (EEOS) on the physicochemical properties, as well as the antioxidant and antibacterial properties, of CS/κC films were also discussed. The addition of ethanol extract of onion skin inhibited the recrystallization of starch molecules in the composite films. It affected the microstructure of the composite films. The color of the composite films was deepened, the brightness was reduced, and the opacity was increased. Water vapor permeability increased, tensile strength decreased, and elongation at the break increased. The glass-transition temperature decreased. The clearance of DPPH radicals and ABTS cation radicals increased. Moreover, when the concentration of EEOS was 3%, the antioxidant effect of the films on oil was greatly improved and could effectively inhibit Staphylococcus aureus and Escherichia coli. The above results showed that adding ethanol extract of onion skin improved the physicochemical properties and biological activities of the CS/κC composite films, so CS/κC/EEOS composite films can be used as an active packaging material to extend food shelf-life. These results can provide a theoretical basis for the production and application of corn starch/κ-carrageenan/ethanol extract of onion skin composite films.

This study investigated the effects of temperature on the drying behavior and kinetic features of lily scales. A series of experiments were carried out at 65, 75, and 85 °C to dry the scales in a laboratory air-ventilated oven dryer. Drying temperature was found to significantly affect drying times and drying rates. The rate curves suggested that the drying process of lily scales occurred entirely within the descending rate period. During the simulation of drying kinetics, Page and Logarithmic models were proven highly accurate by evaluating the efficacy of seven different thin layer models. Based on Fick's second law, the effective moisture diffusivity was determined as 4.12 × 10 −9 , 7.71 × 10 −9 , and 9.49 × 10 −9 m 2 /s for temperatures of 65, 75, and 85 °C, respectively. The calculated figure of activation energy was 42.42 kJ/mol.

In this study, the effects of ethanolic extract from onion skin (EEOS) on the storage quality of refrigerated beef patties were studied. EEOS concentrations of 0.00%, 0.01%, 0.05%, and 0.10% were added to beef patties. These beef patties were stored at 4 °C for 12 days and compared with 0.05 V C treatment group. At the end of storage, compared to control, 0.1% EEOS effectively reduced the contents of metmyoglobin (MetMb) (P < 0.05) and thiobarbituric acid reactants (TBARS) (P < 0.05) in beef patties by 30.89% and 44.72%, respectively. On day 12, the carbonyl contents in 0.1% EEOS treatment increased only 3.3 times, lower than control and V C treatment (4.5 and 4.1 times). Microbial contamination was significantly inhibited (P < 0.05). The antioxidant and antibacterial effects of EEOS were the main reasons for the improvement of pH and a* stability of beef patties. However, the addition of EEOS had no significant effect on cooking loss and texture properties except hardness and springiness. Overall, 0.1% EEOS had a positive effect on the sensory characteristics and storage quality of beef patties and could prolong the storage life of beef patties to 9 days. This showed that EEOS as a natural additive has great potential for beef storage and preservation.

An active film composed of corn starch/κ-carrageenan and ethanolic grape seed extract (0, 1, 3, and 5 wt% of GSE on corn starch basis) were successfully prepared using the solvent casting technique. The effects of the different concentrations of ethanolic grape seed extract (GSE) on the physicochemical properties, antioxidant properties, and antibacterial properties of CS/κC films were analyzed. The results showed that the addition of GSE inhibited the recrystallization of starch in the composite film. The glass transition temperature of composite film is 121.65 °C. With the addition of GSE, the surface roughness of the composite film increased, and the cross-section displayed a stratification phenomenon. Meanwhile, when GSE was added to the composite film, the tensile strength of the composite film decreased (3.50 ± 0.27 MPa), the elongation at break increased (36.87 ± 2.08%), and the WVP increased (1.58 ± 0.03 g mm/m2·d· kPa). With the increase of the concentration of GSE in the composite film, the a* value and b* value of the composite film increase, the L* value decreases, and the opacity increases. The lipid oxidation test proved that the composite films containing 1% GSE has a significant inhibitory effect on the oxidation of lard (p < 0.05). The above results indicate that the GSE can be used as a food-grade packaging material and has a good application prospect in the food industry.