Effect of a purification step and the type of internal standard used on fatty acid determination of grass and maize silages

Non-traditional Oils Encapsulation as Novel Food Additive Enhanced Yogurt Safety Against Aflatoxins

BACKGROUND AND OBJECTIVE

Hibiscus oil (HO) and black cumin oil (BCO) are interesting oils which give a source for photochemical. Yoghurt recognized for health benefits, but mycotoxin is a food problem. The aim was adjusting non-traditional capsulated oils for minimizing mycotoxins in dairy products (yoghurt) and biological systems.

MATERIAL AND METHODS

Oils fatty acid composition were evaluated. Micro and nano-emulsion designed to achieve food safety and shelf-life extension. Encapsulated emulsions evaluated by in vitro and in vivo models for several aflatoxins reduction through yogurt fortification model, for in vivo model reduction estimated as enhancement of rat's blood biochemical parameters. Concerning the in vitro model, changes of supplemented yoghurt properties were estimated.

RESULTS

Linoleic followed by oleic acid showed a high content in these oils representing omega fatty acids. Gamma fractions presented in considerable values (>50% of vitamin E). To evaluate encapsulated oils reduction on aflatoxins (AFs), it was estimated for in vitro and in vivo models. The in vitro reduction of aflatoxin B1 (AFB1) and aflatoxin M1 (AFM1) recorded 31.6 and 34.9%, respectively in plain yogurt. However, yogurt fortification by oil-capsules upgraded the ratio for AFB1 (63.9%) and AFM1 (66.4%). The best reduction recorded using BCO fortification. For in vivo study, supplementation of rat's diet by BCO micro-capsule declared an enhancement of biochemical parameters against aflatoxin G1 (AFG1) effects. Fortified yogurt offered enhancement of viscosity and water holding capacity properties.

CONCLUSION

Encapsulated emulsions recorded high AFs reduction in fortified yogurt and experimental rat's model. Yogurt fortification enhanced its quality characteristics and shelf-life that give a recommendation for the application.

Comparative researches on two direct transmethylation without prior extraction methods for fatty acids analysis in vegetal matrix with low fat content

Background

The aim of our work was to compare two methods, both based on direct transmethylation with different reagents, BF₃/MeOH (boron trifluoride in methanol) or HCl/MeOH (hydrochloride acid in methanol), in acid catalysis, without prior extraction, to find the fast, non-expensive but enough precise method for 9 principal fatty acids (lauric, myristic, palmitic, stearic, oleic, linoleic, linolenic, arahidic and behenic acids) analysis in vegetal matrix with low fat content (forage from grassland), for nutrition and agrochemical studies.

Results

Comparatively, between the average values obtained for all analysed fatty acids by the two methods based on direct transmethylation without prior extraction no significantly difference was identified (p > 0.05). The results of fatty acids for the same forage sample were more closely to their average value, being more homogenous for BF₃/MeOH than HCl/MeOH, because of the better accuracy and repeatability of this method. Method that uses BF₃/MeOH reagent produces small amounts of interfering compounds than the method using HCl/MeOH reagent, results reflected by the better statistical parameters.

Conclusion

The fast and non-expensive BF₃/methanol method was applied with good accuracy and sensitivity for the determination of free or combined fatty acids (saturated and unsaturated) in forage matrix with low fat content from grassland. Also, the final extract obtained by this method, poorer in interfering compounds, is safer to protect the injector and column from contamination with heavy or non-volatile compounds formed by transmethylation reactions.