Table 3.
Active agents added directly to coatings.
| Active Agent | Packaging Material | Packaging Function | Processes Used | Food Product Tested/Packaging Type | Active Agent Amount | Main Effects Compared Control Film | References |
|---|---|---|---|---|---|---|---|
| Rosemary extract | PE-LD films | Antioxidant activity | Brushing | Pork patties/direct contact | 0.45 mg/cm2 | The results demonstrated that PE-LD film coated with rosemary was the most effective active packaging to protect pork patties storage during 60 days at 5 °C. | [37] |
| Natural extract obtained from a brewery residual | PE-LD films | Antioxidant activity | Plate coater | Beef/headspace | 3.2 g/m2 | The results showed that active antioxidant films coated with natural extracts decreased lipid oxidation by up to 90% during 17 days stored at 4 °C. | [63] |
| Pyrogallol (PG) (a natural phenolic compound) | PE-LD films modified with sodium carbonate | Oxygen scavengers | Plate stripe coater | Soybean oil/headspace | Thickness 60—62 µm |
The soybean oil samples packed with PE-LD/PG films coated with 10 and 20% PG and storage at 23 °C and 60 °C showed a better stabilizing effect during 30 days than oil packaged with pure PE-LD. | [64] |
| Chitosan, lauric arginate ester (LAE), sodium lactate (NaL), and sorbic acid (SA) | PLA films | Antimicrobial activity | Brushing or spraying | Ready-to-eat meat (RTE)/direct contact | 0.39 and 1.92 mg/cm2 of Chitosan; 1.94 and 3.89 µg/cm2 of LAE; 0.78, 1.56, 3.89 and 7.78 mg/cm2 of NaL and 0.12 and 0.23 mg/cm2 of SA | The results showed that PLA films containing LAE were those that most significantly inhibited the growth of the tested microorganisms. The PLA films coated with NaL, and SA showed to reduce significantly the growth of L. innocua but were less effective against Salmonella. | [65] |
| Chitosan and ZnO/chitosan | PE-LD films | Antimicrobial activity | Spraying (and plasma treatment) | Okra/ns | Not specified | The results showed that total bacterial concentrations in films coated with chitosan/ZnO coatings were reduced by 63%. | [72] |
| Chitosan and Ag/chitosan | Ethylene copolymer (EVA) film | Antimicrobial activity | Plate coater (and corona treatment) | Beef and chicken meat exudates/ns | Not specified | The film coated with chitosan reduced colony counts of E. coli 25922 and of L. monocytogenes Scott A by 5 and 2–3 log10, respectively, after 24 h exposure. However, this activity was increased when silver ions were incorporated into the films that, for example, originated the complete killing of E. coli O157:H7 DD3795. | [67] |
| Oregano essential oil and green tea extract | Multilayer film: PET/PE/EVOH/PE | Antioxidant activity | Rollers, tampograph, serigraphy or spraying systems | Foal steaks/ns | 1.5and 2.0 g/m2 | The active films with essential oregano oil were significantly more efficient than those with green tea extract in case of extended fresh odor and color from 7 to 14 days, compared to the control. | [10] |
| Oregano extract | PP film | Antioxidant activity | Rollers, tampograph, serigraphy or spraying systems | Fresh beef//ns | Not specified | The results showed to be efficient in extending the fresh odor and color from 14 to 23 days. However, the addition of oregano should be around 1% due to the unacceptable oregano odor when the concentration is higher. | [62] |
| Star anise essential oil (SAEO) and thymol (TH) | Multilayer film PP/SAEO/PET/TH/PE-LD | Insect repellent and antimicrobial activity | Automatic control coater | Slices bread/ns | Thickness of active coating was 13.20 ± 1.72 µm | The developed film showed a strong and sustained insect repellent activity, lower microbial counts and better visual appearance of bread after 14 days of storage. | [69] |
| Green tea extract | Multilayer film: OPP/OPP |
Antioxidant activity | Lamination | Dark chocolate peanuts and milk chocolatecereals/headspace | Not specified | The results demonstrated that it is possible to increase the shelf life of these products from 9 to 18 months without active agent migration from packaging. | [42] |
| Sage leaf (SL) and Bay leaf (BL) extracts | Multilayer film: PET/PE-LD |
Antioxidant activity | Coating machine (KK coater, RK print). | Fried potatoes/headspace | 0.025 and 0.03 g/m2 | The results showed a strong antioxidant activity of SL and BL, either evaluated alone or as food packaging for fried potatoes. For example, in case of the malondialdehyde (MDA) the SL extract was more efficient, showing a reduction of 40% of MDA compared to the control, while BL showed a reduction of 31%. | [43] |
Legend: nd—not determined. ns—not specified if the active agent reacts by direct contact or headspace.