The effects of heat treatment and the addition of tarragon essential oil on physical and mechanical properties of films prepared with 5% whey protein isolate (WPI) and 5% glycerol were investigated in this study. Heat treatment of the film-forming solution caused increases in thickness, moisture content, swelling degree, water vapor permeability (WVP), b*-value, ΔE*-value, transmittance values in the 200–300-nm region, transparency, and puncture resistance of the film, but decreases in water solubility, L*-value, a*-value, transmittance values in the 350–800-nm region, and puncture deformation. When incorporated with tarragon essential oil, heat-treated films have the potential to be used as antimicrobial food packaging. The addition of tarragon essential oil in film-forming solution caused increases in moisture content, solubility in water, WVP, a*-value, b*-value, ΔE*-value, and transparency of the film; decreases in transmittance values in the range of 600–800 nm; and variations in swelling degree, L*-value, transmittance values in the range of 300–550 nm, puncture resistance, and puncture deformation. Nevertheless, different tendencies were noticed in UNT (untreated) and HT (heat-treated) films with regards to transparency, light transmittance, puncture resistance, and puncture deformation. Based on these findings, HT films show improved physical and mechanical properties and, therefore, are more suitable for food-packaging applications.

Fresh fish is extensively consumed and is one of the most-traded food commodities in the world. Conventional preservation technologies include vacuum and modified atmosphere packaging, but they are costly since requires capital investment. In the last decade, research has been directed towards the development of antimicrobial packaging systems, as an economical alternative to these. This paper outlines antimicrobial films and coatings applied so far on fresh fish, their efficacy against targeted microorganism/group and effects on chemical quality of the product. Findings show that edible films/coatings incorporated with different active agents applied to fresh fish are able to inhibit the microbial growth and decrease the rate of fish nutrients degradation, thus preventing the formation of chemical metabolites; a shelf-life extension of 6 to 13 days was obtained for fish fillets, depending on the species on which the active packaging materials were applied. The manufacturing use of these formulations could lead to a significant reduction in fish waste, consequently, a diminution of economic losses for fish traders and retailers. Therefore, their industrial production and commercialization could be an exploitable sector by the packaging industry.

This study is focused on the comparison and classification of parsley, lovage, basil, and thyme essential oils (EOs) based on their chemical composition, total phenolic content, antioxidant and antibacterial activities by using appropriate chemometric methods: Principal component analysis (PCA) and hierarchical cluster analysis (HCA). The results showed that parsley, lovage, and thyme EOs are rich in monoterpene hydrocarbons, but basil EO is rich in oxygenated monoterpenes and phenylpropanoids, and that both PCA and HCA separated essential oils into two main groups of which one contains two sub-groups. β-Phellandrene was the major component identified in parsley and lovage EOs, estragole was the major component in basil EO, and p-cymene was the major component in thyme EO. Thyme EO showed the highest level of total phenolics, the highest antioxidant capacity, and exhibited the stronger antibacterial activity, results that were emphasized by both chemometric methods used. Among tested essential oils, the one of parsley was distinguished by a low total TPC, weak antioxidant activity, and weak antibacterial activity against S. enteritidis (ATCC 13076); lovage EO by low TPC, weak antioxidant activity, but moderate antibacterial activity; and basil EO by low TPC, moderate antioxidant activity, and weak antibacterial activity against L. monocytogenes (ATCC 19114).

The efficiency of some films prepared from heat-denatured whey protein isolate solutions on the quality and shelf-life of brook trout samples during storage at 4 °C was studied in this research (WPIf-a film based on whey protein isolate and WPIf+2.5%TEO-a film based on whey protein isolate incorporated with 2.5% tarragon essential oil). The control and covered fish samples were periodically assessed (at 3 days) over 15 days of storage for the physicochemical (pH; EC, electrical conductivity; TVB-N, total volatile basic nitrogen; TBARS, thiobarbituric acid reactive substances; color), microbiological (TVC, total viable count PTC, psychrotrophic count; LAB, lactic acid bacteria H2S-producing bacteria), and sensory properties (color discoloration; odor; overall acceptability). The WPIf+2.5%TEO has proven enhanced quality preservation effects compared to WPIf by showing lower values for physicochemical parameters, lower microbial loads, and higher sensory scores in the fish sample. All these effects have led to an extension of the sample’s shelf-life. In conclusion, the tarragon essential oil has conferred antioxidant and antimicrobial properties to the film. Thus, the WPIf+2.5%TEO could be a promising material for the packaging of fresh brook trout during refrigerated storage.

Edible mushrooms are well-known for their nutritional benefits and low energy density. In addition, mushroom extracts contain various bioactive compounds that account for their antioxidant activity; the applied extraction conditions influence the extraction efficiency of such compounds. Therefore, this study investigates the effects of four extractants on the content of polyphenols and antioxidant properties of Boletus edulis and Cantharellus cibarius mushrooms, aiming to optimize the extraction process. Powders of B. edulis and C. cibarius mushrooms were subjected to extraction with acidic water (10% CH3COOH), ethanol/water/acetic acid (15:76.5:8.5, v/v/v), hexane, and diethyl ether to measure their total phenolic content (TPC), total flavonoid content (TFC), and Trolox equivalent antioxidant capacity (TEAC). Furthermore, the level of individual polyphenolic compounds in these extracts was quantified using an HPLC-DAD-ESI-MS method. Results showed that the type of solvent significantly influenced the TPC and TEAC of mushroom powder but insignificantly influenced the TFC. A very strong positive correlation was found between TPC and TEAC, but no correlation was found between TFC and TEAC or TPC and TFC. Acidic water extracted the highest amount of polyphenolic compounds from these mushroom powders. Therefore, the aqueous extract showed the highest TPC and strongest antioxidant activity. Thus, acidic water is recommended for polyphenol analysis in B. edulis and C. cibarius mushrooms.

Over the past decade, there has been growing interest in polyphenols’ research since these compounds, as antioxidants, have several health benefits, such as preventing neurodegenerative diseases, inflammation, cancer, cardiovascular diseases, and type 2 diabetes. This study implements an analytical method to assess the total phenolic content (TPC) in essential oils using Folin–Ciocalteu’s phenol reagent and quantifies the individual phenolic compounds by liquid chromatography. Thus, the research design and methodology included: (1) extraction of essential oil from dried thyme leaves by hydrodistillation; (2) spectrophotometric measurement of TPC by Folin–Ciocalteu method; and (3) identification and quantification of individual phenolic compounds by high-performance liquid chromatography-diode array detection/electrospray ionization mass spectrometry (HPLC-DAD-ESI-MS). Results revealed a TPC of 22.62 ± 0.482 mg GAE/100 µL and a polyphenolic profile characterized by phenolic acids (52.1%), flavonoids (16.1%), and other polyphenols (31.8%). Thymol, salvianolic acid A, and rosmarinic acid were the major compounds of thyme essential oil. The proposed analytical procedure has an acceptable level of repeatability, reproducibility, linearity, LOD (limit of detection), and LOQ (limit of quantification).

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