Comparative study of the simultaneous action of three essential oils on Aspergillus flavus and Sitophilus zeamais Motsch

Development of a Gas Chromatography-Flame Ionization Method for the Detection and Quantification of 12 Flavoring Agents in Supplementary Feed

A flavoring agent is a compound that serves to add flavor with a pleasant scent and is used as a feed additive. Current flavor analysis methods include reflux pretreatment, titration, neutralization titration, and inversion; these are all analytical methods in which deviations and errors between experiments are generated. Titration methods are characterized by difficult selectivity analysis both for mixtures containing two or more types of flavoring agents and also for very low content samples. Current analysis methods are therefore particularly unsuitable for these sample types. Thus, more precise and accurate analysis of flavor agents is needed. This study intends to develop and verify a multi-component simultaneous analysis method that can accurately confirm the guaranteed content of 12 flavor agents of supplementary feeds distributed in the market, the goal being to establish a universally trusted method. Method validation was performed according to the International Conference on Harmonization (ICH) and International Union of Pure and Applied Chemistry (IUPAC) guidelines. Method

validation was performed in terms of linearity, sensitivity, selectivity, accuracy, and precision. The limits of detection (LOD) for the instrument employed in these experiments ranged from 0.44–4.77 mg/kg, and the limits of quantification (LOQ) ranged from 1.32–14.31 mg/kg. Average recoveries of the 12 flavoring agents ranged from 75.1–111.4%. Maximum %RSD values for intraday and interday peak area variation are 13.09% and 13.08%, respectively. A novel and simple method for detecting 12 flavoring agents in animal feed supplements using a gas chromatography-flame ionization detector (GC-FID) was developed.

Cultural and Genetic Approaches to Manage Aflatoxin Contamination: Recent Insights Provide Opportunities for Improved Control

Aspergillus flavus is a morphologically complex species that can produce the group of polyketide derived carcinogenic and mutagenic secondary metabolites, aflatoxins, as well as other secondary metabolites such as cyclopiazonic acid and aflatrem. Aflatoxin causes aflatoxicosis when aflatoxins are ingested through contaminated food and feed. In addition, aflatoxin contamination is a major problem, from both an economic and health aspect, in developing countries, especially Asia and Africa, where cereals and peanuts are important food crops. Earlier measures for control of A. flavus infection and consequent aflatoxin contamination centered on creating unfavorable environments for the pathogen and destroying contaminated products. While development of atoxigenic (nonaflatoxin producing) strains of A. flavus as viable commercial biocontrol agents has marked a unique advance for control of aflatoxin contamination, particularly in Africa, new insights into the biology and sexuality of A. flavus are now providing opportunities to design improved atoxigenic strains for sustainable biological control of aflatoxin. Further, progress in the use of molecular technologies such as incorporation of antifungal genes in the host and host-induced gene silencing, is providing knowledge that could be harnessed to develop germplasm that is resistant to infection by A. flavus and aflatoxin contamination. This review summarizes the substantial progress that has been made to understand the biology of A. flavus and mitigate aflatoxin contamination with emphasis on maize. Concepts developed to date can provide a basis for future research efforts on the sustainable management of aflatoxin contamination.

Insectifugal and insecticidal potentials of two tropical botanical essential oils against cowpea seed bruchid

Essential oils (EO) obtained from Xylopia parviflora root bark and Hoslundia opposita leaf via hydro distillation were analysed by GC-MS and evaluated for their insectifugal (repellent) and insecticidal activities against cowpea seed bruchid (Callosbruchus maculatus Fabricius), a cosmopolitan pest of cowpea seeds. X. parviflora was predominated by sesquiterpenes (59.57%), with the main compounds being β-himachalene (22.68%), 1,7,7,Trimethylbicyclo[2.2.1]hept-5-en-2-ol (19.68%), β-elemene (14.41%), 5(1H)-Azulenone, 2,4,6,7,8,8a-hexahydro-3,8-dimethyl-4-(1-methylethylidene)-(85-cis)- (12.38%) and (-)-α-parasinsen (8.34%). The predominant compounds in H. opposita EO were 1,8-cineole (61.15%), followed by α-terpineol (16.81%) and β-phellandrene (13.25%). Percentage repellence at application rates of 0.66-1.32 μl/cm² (46.93-73.07%) was significantly (p < 0.05) higher than that of control (17.73%). RD₅₀ (repellence dose for 50% of treated adults) for H. opposita (0.43 μl/cm²) was not significantly different from the value for X. parviflora (0.60 μl/cm²). Although higher percentage of male mortality than female mortality was observed due to topical application of the EOs, the disparity was not significant. The results of correlation of the chemical groups of the EOs with the insectifugal activity indicate that the observed bioactivity was due to the synergistic effects of the chemical groups. The two EOs are therefore recommended for incorporation into bruchid protection schemes in the tropics.

Efficacy of Angelica archangelica essential oil, phenyl ethyl alcohol and α- terpineol against isolated molds from walnut and their antiaflatoxigenic and antioxidant activity

Mold association, aflatoxin B1 contamination as well as oxidative deterioration of agri-food items during storage and processing are some global task for food industries. In view of the adverse effects of some synthetic preservatives on treated food items and subsequently on consumers health, recently plant based chemicals are encouraged by food industries as better alternatives of synthetics. The present study recommends the combination (1:1:1) of Angelica archangelica essential oil: Phenyl ethyl alcohol (PEA): α- terpineol as botanical preservative against molds, aflatoxin contamination and oxidative deterioration of walnut samples. Eight mold species were procured from stored walnut samples, including some aflatoxigenic Aspergillus flavus strains. The combination inhibited growth of aflatoxigenic strain Aspergillus flavus NKDW-7 and aflatoxin B1 production at 2.25 and 2.0 μL mL(-1) respectively. The IC50 value of the combination was recorded as 3.89 μL mL(-1), showing strong antioxidant potential. The antifungal action of the combination showed > 90 % decrease in ergosterol content in plasma membrane of A. flavus at 2.0 μL mL(-1). The LD50 of the combination, through oral administration on mice, was 9562.9 μL kg(-1) body weight, indication favourable safety profile as a plant based preservative. The combination may be recommended as safe preservative against molds, aflatoxin contamination and oxidative deterioration of walnut samples.