Cristiana M.P. Yoshida

Chitosan/pectin polyelectrolyte complex as a pH indicator.

A polyelectrolyte complex (PEC) matrix formed between chitosan and pectin was developed to entrap a bioactive compound (anthocyanin), obtaining an useful pH indicator device. Polysaccharides of opposite charges such as chitosan and pectin can have a very strong intermolecular interaction. The innovation lies in obtaining a new system based on natural and biodegradable compounds, which is simple to manufacture, to indicate variation in pH by visual changes in colour. This device has potential applications in food packaging. The PEC was studied using chitosan and pectin solutions at different pHs values (3.0, 4.0, 5.0 and 5.5) and pectin/chitosan molar ratios (1.0 to 10/1.0 to 5.0). PEC films were homogeneous and showed the highest yield (60.0%) at pH 5.5. Diffusion tests indicated efficient bioactive compound entrapment in the PEC matrix. Thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy indicate the compatibility between the polymers and bioactive compound.

Sistemas inteligentes de embalagens utilizando filmes de quitosana como indicador colorimétrico de temperatura

Chlorophyll was incorporated into chitosan films, forming intelligent systems able to detect variations in temperature. Chitosan is a biodegradable polymer that forms flexible, resistant films with an efficient oxygen barrier. Chlorophyll was added (0.25 g/100 g) into chitosan suspension (2.00 g/100 g) and intelligent films (FIQ) were cast. The effects of temperature (10 °C to 50 °C) and luminosity (0 to 1000 lx) on the films were studied using an experimental design with two variables, analyzing the color parameters L*, a*, b* and mechanical properties. The films were characterized according to their homogeneity, flexibility, color and handling. Chitosan suspensions containing chlorophyll were also applied as coating on the surface of pieces of card-paper, forming a card paper film system (S-FP). By visual inspection we observed the color of the S-FP changing irreversibly from green to yellow when the temperature was above 50 °C. Therefore, the S-FP system can potentially be used as a colorimetric indicator for the 50 °C to 70 °C range, being advantageous owing to the ease of fabrication, biodegradability, safe use for food and low cost.

Chitosan-based nanocomposites for drug delivery

Abstract Chitosan (CS) is a semi-synthetic biopolymer obtained from chitin that is the second most abundant biopolymer. Many devices produced from CS have been widely used for drug delivery systems and biomaterials. Biocompatibility, biodegradability, nonallergenicity, and antimicrobial activity are advantageous properties of CS; moreover, CS has also exhibited healing properties. Some properties can be potentiated by using the CS to produce CS-based nanocomposites. In this sense, this chapter intends to give some CS nanodevices with different kind of fillers (reinforcements) and their application to the drug delivery systems. Fillers such as nanoparticles, nanolayer, and nanofibrous are discussed.

Chitosan active films containing agro-industrial residue extracts for shelf life extension of chicken restructured product

This study aimed to develop chitosan films incorporating natural antioxidants from peanut skin (EPS) and pink pepper residue (EPP) extracts, as well as to evaluate their effects on lipid oxidation, pH, color, and microbial counts of a restructured chicken product. EPS had higher phenolic content and antioxidant activity compared to EPP. When both extracts were applied to chicken meat and the chitosan films, there were no differences for color, pH and total mesophilic counts compared to control at the end of the storage period. For lipid oxidation (peroxide value and thiobarbituric acid reactive substances), both extracts proved to be as effective as butylated hydroxytoluene to maintain the oxidative stability of the chicken product. The microbial counts of psychrotrophic microorganisms were significantly lower for treatments with active films. Chitosan active films with residue extracts may maintain the quality of chicken products due to their antioxidant and antimicrobial potential.

Agronomic Cultivation, Chemical Composition, Functional Activities and Applications of Pereskia Species – A Mini Review

BACKGROUND The exploration of the plant biodiversity as a natural source to obtain sustainable food products and new bioactive pharmaceutical compounds has been growing significantly due to their abundance, safety and economy. Natural compounds present some advantages when compare to the synthetic ones such as they are chemically inert, non-toxic, less expensive, biodegradable and widely available. In this sense, plants of the genus Pereskia belonging to the Cactaceae family, have been studied. It is an unconventional wild edible plant that contains a large amount of protein and minerals. Studies have demonstrated their biological activities and potential application in different areas such as pharmaceutical, medicinal and food. OBJECTIVE This review is focused on the chemical composition, functional properties, applications on pharmaceutical, nutraceutical and food areas and formulation techniques to enhance stability and bioavailability of bioactive compounds from the underutilized wild edible plant known as ora-pro-nobis (Pereskia aculeata or Pereskia grandifolia). CONCLUSION The latest studies involving ora-pro-nobis demonstrated its great potential due to its biological activities, which could stimulate further investigations. The utilization of this plant as a natural source to supplement the diet, or to prepare new food formulations and pharmaceutical products would be an optimum possibility to explore the rich biodiversity found in Brazil and in other countries.