tannins and cinnamaldehyde

Tannins are plant defense substances that exhibit a strong astringent taste and precipitate proteins, leading to the inhibition of protein functions; however, owing to their relatively low toxicity, tannins must be accumulated in high concentrations in cell vacuoles. Therefore, the solubility of tannins is crucial for their functions. In this review, the structure and reactions of tannins related to solubility; insolubilization of persimmon proanthocyanidins on fruit ripening; pigment formation from cinnamon procyanidins by reaction with cinnamaldehyde in case of wounding; and insolubilization of ellagitannins in chestnut wood is discussed. In addition, the development of functional polyphenols including oil-soluble tea catechins is introduced.

Topics: Acrolein; Aesculus; Antioxidants; Catechin; Cinnamomum zeylanicum; Diospyros; Hydrolyzable Tannins; Oils, Volatile; Oxidation-Reduction; Polyphenols; Proanthocyanidins; Solubility; Tannins; Tea; Water

Chitosan (CS) films have poor mechanical property, low water-resistance and limited antimicrobial activity, which hinder their application in food preservation industry. Cinnamaldehyde-tannic acid-zinc acetate nanoparticles (CTZA NPs) assembled from edible medicinal plant extracts were successfully incorporated into CS films to solve these issues. The tensile strength and water contact angle of the composite films increased about 5.25-fold and 17.55°. The addition of CTZA NPs reduced the water sensitivity of CS films, which could undergo appreciable stretching in water without breaking. Furthermore, CTZA NPs significantly enhanced the UV adsorption, antibacterial, and antioxidant properties of the films, while reduced their water vapor permeability. Moreover, it was possible to print inks onto the films because the presence of the hydrophobic CTZA NPs facilitated the deposition of carbon powder onto their surfaces. The films with great antibacterial and antioxidant activities can be applied for food packaging application.

Topics: Anti-Bacterial Agents; Antioxidants; Chitosan; Food Packaging; Nanoparticles; Tannins; Tensile Strength; Zinc Acetate

Antimicrobial essential oils are incorporated into mussel-inspired and natural plant polyphenol coatings as part of a single-step fabrication process. Polydopamine-cinnamaldehyde, polyethyleneimine-cinnamaldehyde, and tannic acid-cinnamaldehyde coatings exhibit strong antibacterial activities against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus (with the polydopamine- and tannic acid-based systems displaying log

Topics: Acrolein; Anti-Bacterial Agents; Coated Materials, Biocompatible; Escherichia coli; Indoles; Microbial Sensitivity Tests; Polymers; Polypropylenes; Staphylococcus aureus; Surface Properties; Tannins; Textiles

Cinnamomi cortex, which is normally referred to as cinnamon, is a very popular spice as well as an important natural medicine. High-quality cinnamon is traditionally believed to taste sweet and be strongly pungent without astringency. Cinnamomi cortex with larger amounts of cinnamaldehyde was sweeter in taste comparisons. The contents of tannins and sugars in cinnamon powder had little effect on the taste. Evaluations of the sweetness and pungency of cinnamaldehyde solutions (0.1, 0.25, 0.50, 0.75, 1.0, and 5.0 mg/ml) were performed using volunteers. The scores for sweetness increased significantly from 0.10 to 0.50 mg/ml (P < 0.05, Mann-Whitney U-test), but there was no significant difference above 0.75 mg/ml. The concentration threshold for the sweet taste of cinnamaldehyde appeared to be less than 0.75 mg/ml, and the more concentrated solutions gave excessive pungency. Therefore, two contrastive tastes of Cinnamomi cortex, sweet and pungent, were both attributed to cinnamaldehyde. Consequently, its taste, one of its indices of quality, seems to vary mainly according to the content of cinnamaldehyde.

Topics: Acrolein; Carbohydrates; Cinnamomum zeylanicum; Humans; Tannins; Taste

The inhibitory effect of some plant oil aromatics against three strains of Arcobacter butzleri, two strains of Arcobacter cryaerophilus, and one strain of Arcobacter skirrowii was evaluated. When MICs were determined using the broth macrodilution method, cinnamaldehyde was most inhibitory followed by thymol, carvacrol, caffeic acid, tannic acid, and eugenol (P < 0.001). Sublethal concentrations of the three most potent plant oil aromatics also were examined. Overall, cinnamaldehyde was the most bacteriostatic against all arcobacters tested except A. butzleri when these strains were exposed to the MIC25 of this aromatic aldehyde. The bacteriostatic activities of thymol and carvacrol were concentration and species dependent.

Topics: Acrolein; Arcobacter; Caffeic Acids; Colony Count, Microbial; Consumer Product Safety; Cymenes; Dose-Response Relationship, Drug; Eugenol; Food Preservation; Food Preservatives; Humans; Microbial Sensitivity Tests; Monoterpenes; Plant Oils; Species Specificity; Tannins; Thymol