Condensed tannins, attine ants, and the performance of a symbiotic fungus

Aflatoxin B1 (AFB1) is a potent carcinogenic mycotoxin that contaminates numerous crops pre- and post-harvest. To protect foods and feeds from such toxins without resorting to pesticides, the use of plant extracts has been increasingly studied. The most interesting candidate plants are those with strong antioxidative activity because oxidation reactions may interfere with AFB1 production. The present study investigates how an aqueous extract of Mimosa tenuiflora bark affects both the growth of Aspergillus flavus and AFB1 production. The results reveal a dose-dependent inhibition of toxin synthesis with no impact on fungal growth. AFB1 inhibition is related to a down-modulation of the cluster genes of the biosynthetic pathway and especially to the two internal regulators aflR and aflS. Its strong anti-oxidative activity also allows the aqueous extract to modulate the expression of genes involved in fungal oxidative-stress response, such as msnA, mtfA, atfA, or sod1. Finally, a bio-guided fractionation of the aqueous extract demonstrates that condensed tannins play a major role in the anti-aflatoxin activity of Mimosa tenuiflora bark.

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Fractionation of condensed tannins by counter-current chromatography

Journal of Chromatography A ◽

10.1016/s0021-9673(01)90666-1 ◽

1985 ◽

Vol 318 ◽

pp. 85-93 ◽

Cited By ~ 39

Author(s):

Lesley J. Putman ◽

Larry G. Butler

Keyword(s):

Condensed Tannins ◽

Counter Current

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Optimization Model of Phenolics Encapsulation Conditions for Biofortification in Fatty Acids of Animal Food Products

Foods ◽

10.3390/foods10040881 ◽

2021 ◽

Vol 10 (4) ◽

pp. 881

Author(s):

Roberta Tolve ◽

Fernanda Galgano ◽

Nicola Condelli ◽

Nazarena Cela ◽

Luigi Lucini ◽

...

Keyword(s):

Fatty Acids ◽

Condensed Tannins ◽

Encapsulation Efficiency ◽

Biological Effects ◽

Fatty Acid Content ◽

Food Products ◽

Animal Origin ◽

Animal Nutrition ◽

Loading Capacity ◽

Wide Range

The nutritional quality of animal products is strongly related to their fatty acid content and composition. Nowadays, attention is paid to the possibility of producing healthier foods of animal origin by intervening in animal feed. In this field, the use of condensed tannins as dietary supplements in animal nutrition is becoming popular due to their wide range of biological effects related, among others, to their ability to modulate the rumen biohydrogenation and biofortify, through the improvement of the fatty acids profile, the derivate food products. Unfortunately, tannins are characterized by strong astringency and low bioavailability. These disadvantages could be overcome through the microencapsulation in protective matrices. With this in mind, the optimal conditions for microencapsulation of a polyphenolic extract rich in condensed tannins by spray drying using a blend of maltodextrin (MD) and gum Arabic (GA) as shell material were investigated. For this purpose, after the extract characterization, through spectrophotometer assays and ultra-high-performance liquid chromatography-quadrupole time-of-flight (UHPLC-QTOF) mass spectrometry, a central composite design (CCD) was employed to investigate the combined effects of core:shell and MD:GA ratio on the microencapsulation process. The results obtained were used to develop second-order polynomial regression models on different responses, namely encapsulation yield, encapsulation efficiency, loading capacity, and tannin content. The formulation characterized by a core:shell ratio of 1.5:5 and MD:GA ratio of 4:6 was selected as the optimized one with a loading capacity of 17.67%, encapsulation efficiency of 76.58%, encapsulation yield of 35.69%, and tannin concentration of 14.46 g/100 g. Moreover, in vitro release under varying pH of the optimized formulation was carried out with results that could improve the use of microencapsulated condensed tannins in animal nutrition for the biofortification of derivates.

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