Marco A. López-Mata

Physicochemical, Antimicrobial and Antioxidant Properties of Chitosan Films Incorporated with Carvacrol

Chitosan films (CF) with carvacrol (CAR) [0.5%, 1.0% and 1.5% v/v] were prepared by the emulsion method. The retained CAR, water solubility, water vapor permeability (WVP), optical, mechanical properties, antibacterial and antioxidant capacity of films were analyzed. The results indicate that the retention of CAR in the CF was ≈50%. The incorporation of CAR to CF decreased the water solubility, the WVP, the yellowing and transparency and the tensile strength, but increased the stiffness. Microcapsules with diameters of 2 to 7 µm were found on the surface CF-CAR. The CF-CAR with highest CAR concentrations showed antibacterial activity against S. typhimurium and E. coli O157:H7. The CF-CAR had higher antioxidant capacity and an increased protective effect against oxidation of erythrocytes in different grades. These results suggest potential applications of CF-CAR as active packaging to preserve food products.

Physicochemical and Antioxidant Properties of Chitosan Films Incorporated with Cinnamon Oil

Chitosan films (CF) with cinnamon bark oil (CO) incorporated at 0% (control), 0.25%, 0.5%, and 1.0% v/v were prepared by an emulsion method. The films were characterized based on their physical properties (solubility, water vapor permeability, optical property, and microstructure) and antioxidant properties (DPPH, ABTS, and its protective effects on human erythrocytes). The results showed that the incorporation of 0.5 and 1.0% of CO into the CF significantly decreased its solubility to 22% of the control (). The water vapor permeability of the CF-CO was significantly reduced to 40% with low concentrations of CO (0.25%) incorporated into the CF. In general, the films presented a yellow coloration and an increase in transparency with the incorporation of CO into the CF. It was also observed that the incorporation of CO increased the antioxidant activity between 6.0-fold and 14.5-fold compared to the control, and the protective capacity against erythrocyte hemolysis increased by as much as 80%.

Total Phenolic, Flavonoid, Tomatine, and Tomatidine Contents and Antioxidant and Antimicrobial Activities of Extracts of Tomato Plant

The purpose of this study was to evaluate the antioxidant and antimicrobial properties of extracts of different fractions of two tomato plant cultivars. The stems, roots, leaves, and whole-plant fractions were evaluated. Tomatine and tomatidine were identified by HPLC-DAD. The leaf extracts from the two varieties showed the highest flavonoids, chlorophyll, carotenoids, and total phenolics contents and the highest antioxidant activity determined by DPPH, ABTS, and ORAC. A positive correlation was observed between the antioxidant capacities of the extracts and the total phenolic, flavonoid, and chlorophyll contents. The Pitenza variety extracts inhibited the growth of pathogens such as E. coli O157:H7, Salmonella Typhimurium, Staphylococcus aureus, and Listeria ivanovii, yielding inhibition halos of 8.0 to 12.9 mm in diameter and MIC values of 12.5 to 3.125 mg/mL. These results suggest that tomato plant shows well potential as sources of various bioactive compounds, antioxidants, and antimicrobials.

Chemical constitution and effect of extracts of tomato plants byproducts on the enteric viral surrogates

Byproducts of tomato are known to include phenolic compounds but have not been studied in depth. In this study, the phenolic compositions of (stem, leaf, root, and whole plant) of two tomato cultivars, Pitenza and Floradade, were analyzed by HPLC-DAD. In parallel, the antiviral effects of crude extracts on viral surrogates, the bacteriophages MS2 and Av-05 were evaluated. The leaf extracts from the two varieties showed the highest concentration of phenolic compounds. The compounds identified were gallic acid, chlorogenic acid, ferulic acid, cafeic acid, rutin, and quercetin, and they represented 3174.3 and 1057.9 mg/100 g dried weight of the Pitenza and Floradade cultivars, respectively. MS2 and Av-05 titers at 5 mg/mL were reduced by 3.47 and 5.78 log10 PFU/mL and 3.78 and 4.93 log10 PFU/mL by Pitenza and Floradade cultivar leaf extract, respectively. These results show that tomato extracts are natural sources of bioactive substances with antiviral activity.

Mechanical, Barrier and Antioxidant Properties of Chitosan Films Incorporating Cinnamaldehyde

Chitosan films (CF) [1 and 2% w/v] alone and with cinnamaldehyde (CNE) [0.25, 0.5 and 1% v/v] were prepared using an emulsion method, and the obtained films were characterized in terms of water vapor permeability (WVP), water solubility and optical, mechanical and antioxidant properties. The incorporation of CNE at 1% (v/v) significantly decreased the water solubility of the film by approximately 4% for the 1 and 2% CF films, whereas the WVP increased (2.5–3.5 times). The incorporation of CNE (0.25 and 0.5%) into 2% CF significantly increased the tensile strength (TS) (62 and 34%, respectively) and the percent elongation (%E) values, 26, 30 and 52% for CF that contained 0.25, 0.5 and 1% CNE, respectively. The largest value of the elasticity modulus (EM) was observed for 2% CF with 0.25% CNE. All films exhibited a yellow appearance (b*), but the CNE content had a marked impact on the coloration of the films. The CNE recoveries of the CF films (1 and 2%) with 1% of CNE were high (43 and 67%). The antioxidant activities indicated that the incorporation of 1% CNE into CF films (1 and 2%) increased the antioxidant activity. The protective effects of the films with and without CNE on erythrocytes were very strong (36–72% hemolysis inhibition). These results suggest there are potential applications for CF-CNE films as active packaging for the preservation of food products.

Phenolic compounds of potato peel extracts: their antioxidant activity and protection against human enteric viruses.

Potato peels (PP) contain several bioactive compounds. These compounds are known to provide human health benefits, including antioxidant and antimicrobial properties. In addition, these compounds could have effects on human enteric viruses that have not yet been reported. The objective of the present study was to evaluate the phenolic composition, antioxidant properties in the acidified ethanol extract (AEE) and water extract of PP, and the antiviral effects on the inhibition of Av-05 and MS2 bacteriophages, which were used as human enteric viral surrogates. The AEE showed the highest phenolic content and antioxidant activity. Chlorogenic and caffeic acids were the major phenolic acids. In vitro analysis indicated that PP had a strong antioxidant activity. A 3 h incubation with AEE at a concentration of 5 mg/ml was needed to reduce the PFU/ml (plaque-forming unit per unit volume) of Av-05 and MS2 by 2.8 and 3.9 log₁₀, respectively, in a dose-dependent manner. Our data suggest that PP has potential to be a source of natural antioxidants against enteric viruses.

Microencapsulation of Carvacrol Using Pectin/Aloe-gel as a Novel Wound Dressing Films

Recently, Pectin (PEC) and Aloe-Gel (AG) have received great attention for their use in the encapsulation of hydrophobic bioactive compounds such as Carvacrol (CAR). The aim of this study is to assess the physical, chemical and biological properties of a novel PEC/AG film and evaluate its capability to entrap CAR into microencapsulates. For this purpose, the casting method was used to prepare the PEC/AG membranes (70:30 % w/w). The CAR-loaded PEC/AG film was prepared adding different proportions of CAR (0.25%, 0.50% and 1.00% v/v) to the mixture of PEC/AG, previously emulsified with tween 80 (1.0%). The optical properties, Water Vapor Permeability (WVP), ATR-FTIR spectroscopy, microstructure, antibacterial activity and size of microcapsules were evaluated. The PEC/AG membranes loaded with CAR showed yellowish appearance and they were transparent to the UV electromagnetic radiation (190, 200 and 280 nm). The film prepared with the lowest amount of CAR (PC/AG-CAR-0.25%) showed the highest values of WVP (66.2%) and, according to SEM micrograph, the largest microcapsules (≈1005± 39 µm3). The FTIR analysis showed the characteristic absorption peaks located at 1015 cm-1 to 1030 cm-1 and a small shoulder to 990 cm-1 of benzene ring 1:2:4 substituted that suggested the presence of CAR-loaded in the PC/AG film. On the other hand, E. coli O157:H7 showed the highest sensitivity to the PEC/AG-CAR-1.00% film, while S. aureus was not sensitive.