A simple one-pot determination of both total phenolic content and antioxidant activity of honey by polymer chemosensors

Gluten-free wafer formulation: Development, characterisation and addition of flavourings with antioxidant capacity

The incidence of celiac disease is increasing, therefore the demand for gluten-free products that also satisfy the nutritional requirements of celiac individuals is rising. Thus, the objective of the present work was to develop a gluten-free nutritionally balanced wafer formulation with a high content of antioxidants. First, the animal fat used in the traditional formulation was successfully replaced by high oleic sunflower. Second, the antioxidant content of several flavourings (cinnamon/honey/anise/vanilla) was measured and their addition to a gluten-free wafer formulation was evaluated. Third, multivariate statistical tools were used to select the formulation that properly mimicked the characteristics of a gluten-containing wafer. According to the results, anise and cinnamon were the most suitable flavourings to prepare gluten-free wafers, and the sensory analysis concluded that these formulations were highly acceptable (means>6.7 on the hedonic scale). Finally, the storage time analysis indicated that the texture of the gluten-free wafers was more susceptible to water absorption than gluten-containing wafers. Besides, cinnamon wafers presented a higher bioaccessible antioxidant capacity than anise wafers (43.5 ± 0.1 mg Trolox/g and 18.8 ± 0.9 mg Trolox/g respectively) (p < 0.05), which remained stable for four months. This indicates that during its shelf life, the product could be consumed with its beneficial effects intact.

Democratization of Copper Analysis in Grape Must Following a Polymer-Based Lab-on-a-Chip Approach

Quality control in the food industry is of the upmost importance from the food safety, organoleptic and commercial viewpoints. Accordingly, the development of in situ, rapid, and costless analytical tools is a valuable task in which we are working. Regarding this point, the copper content of grape must has to be determined by wineries along the wine production process. For this purpose, grape must samples are sent to laboratories where the copper content is measured usually by flame atomic absorption spectrometry or by inductively coupled plasma mass spectrometry. We herein propose a straightforward, rapid, and inexpensive methodology based both on a film-shaped colorimetric polymer sensor and a smartphone method that at the same time can be used by unskilled personnel. The sensory polymer films change their color upon dipping them on the grape must, and the color evolution is analyzed using the digital color parameters of a picture taken to the film with a smartphone. Furthermore, the analytical procedure is automatically carried out by a smartphone app. The limit of detection of copper of the polymer sensor is 0.08 ppm. Following this approach, 18 production samples coming from the French Groupe ICV company were studied. The copper content of the samples was analyzed by the usual procedure carried out by the company (flame atomic absorption spectrometry) and by the method proposed in this work, ranging this content from 0.41 to 6.08 ppm. The statistical study showed that the results of both methods are fully consistent, showing the validity of the proposed method for the determination of copper in grape must within the frame of wine production wineries and industries.

From Classical to Advanced Use of Polymers in Food and Beverage Applications

Polymers are extensively used in food and beverage packaging to shield against contaminants and external damage due to their barrier properties, protecting the goods inside and reducing waste. However, current trends in polymers for food, water, and beverage applications are moving forward into the design and preparation of advanced polymers, which can act as active packaging, bearing active ingredients in their formulation, or controlling the head-space composition to extend the shelf-life of the goods inside. In addition, polymers can serve as sensory polymers to detect and indicate the presence of target species, including contaminants of food quality indicators, or even to remove or separate target species for later quantification. Polymers are nowadays essential materials for both food safety and the extension of food shelf-life, which are key goals of the food industry, and the irruption of smart materials is opening new opportunities for going even further in these goals. This review describes the state of the art following the last 10 years of research within the field of food and beverage polymer's applications, covering present applications, perspectives, and concerns related to waste generation and the circular economy.

Recent Progress, Challenges, and Trends in Polymer-Based Sensors: A Review

Polymers are long-chain, highly molecular weight molecules containing large numbers of repeating units within their backbone derived from the product of polymerization of monomeric units. The materials exhibit unique properties based on the types of bonds that exist within their structures. Among these, some behave as rubbers because of their excellent bending ability, lightweight nature, and shape memory. Moreover, their tunable chemical, structural, and electrical properties make them promising candidates for their use as sensing materials. Polymer-based sensors are highly utilized in the current scenario in the public health sector and environment control due to their rapid detection, small size, high sensitivity, and suitability in atmospheric conditions. Therefore, the aim of this review article is to highlight the current progress in polymer-based sensors. More importantly, this review provides general trends and challenges in sensor technology based on polymer materials.

Identification of Pigmented Substances in Black Honey from Leucosceptrum canum: Novel Quinonoids Contribute to Honey Color

Leucosceptrum canum (Lamiaceae) honey (LCH) is a rare and high-value honey with an unusual dark brown color. Its pigments may be related to the purported health benefits of the honey and could serve as indicators of authentic LCH. Here, we purified the pigmented substances contributing to LCH's color and identified them using high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy. The major pigmented substances were 1-[4-(3-carboxy-propylamino)-3,6-dioxo-cyclohexa-1,4-dienyl]-pyrrolidine-2-carboxylic acid (GPBQ), 1-[4-(3-carboxy-propylamino)-3,6-dioxo-cyclohexa-1,4-dienyl]-pyrrolidine-2-carboxylic acid. (GAPBQ), and 2,5-di-(N-prolyl)-para-benzoquinone (DPBQ). According to UHPLC-DAD data recorded at 370 nm, GPBQ, GAPBQ, and DPBQ contents ranged from 2.58 to 5.13, 2.93 to 4.96, and 4.26 to 9.22 mg/kg, respectively. These amino acid-quinone conjugates, found here for the first time, are pigments that can serve as markers to control the quality of LCH.

A Simple Minimized System Based on Moving Drops for Antioxidant Analysis Using a Smartphone

In this paper, a novel antioxidant analysis is proposed using a simple minimized device based on moving drops as solution handling and a smartphone as a detector. This approach is based on the colorimetric determination of the scavenging activity against 2,2-diphenyl-1-picrylhydrazyl radical (DPPH^•), expressed as the half-maximal inhibitory concentration (IC₅₀), vitamin C equivalent antioxidant capacity (VCEAC), and Trolox equivalent antioxidant capacity (TEAC). A small drop of the positive control or the samples moves by eluting an ethanol drop down by the force of gravity to react with a DPPH^• drop in the detection zone. The color change of DPPH^• is monitored by a smartphone camera, and the color signals are processed using Adobe Photoshop software. The magenta-to-yellow ratio was successfully applied to evaluate the percentage of DPPH^• inhibition with no significant difference compared with the reference spectrophotometric method at a confidence level of 95%. The total phenolic content (TPC) was measured using the Folin–Ciocalteu assay. An application to Miang (fermented tea leaf extract) showed the consonant relationship between the scavenging activity of DPPH^• and TPC.

Polymer film as starch azure container for the easy diastase activity determination in honey

A new original application for a polyacrylic film based on the monomers 2-(dimethylamino)ethyl methacrylate (NNDA), 2-hydroxyethyl acrylate (2HEA) and methylmethacrylate (MMA) as a starch azure container has been set up for a simple determination of honey diastase activity. The proposed method is based on the correlation of reducing sugars generated during the enzymatic process with the Schade reference assay. The polyacrylic film is charged with starch azure acting as a container for this substance; thus, the starch does not interfere in the measurement of reducing sugars, so that the diastase activity is easily calculated. The method has been contrasted with Schade method, showing good correlation and differences under 0.4% between methods in some honey samples. The polyacrylic film has great potential for the routine honey diastase activity assessment in small laboratories, dramatically reducing analysis time and cost.