Search

Abstract: The role of essential fatty acids is vital in the life of a human being. The lack of essential fatty acids causes various diseases, such as cardiovascular, inflammatory bowel, and obesity. Although synthetic antioxidants have already been used, nowadays, the demand for natural antioxidants has increased mainly because of the adverse effects of synthetic antioxidants. Spices are widely used in this context as a source of natural antioxidants. It has been observed that they also act as pro-oxidants. This review aims to evaluate the fundamental reason for the different activities of the spices by studying the example of eugenol, a principal phenolic constituent of clove oil. The chemistry concerning the mechanism to display antioxidant and pro-oxidant activity is currently being reviewed. The isomerization of eugenol to isoeugenol plays a key role in exhibiting dissimilar behaviour of the eugenol. Under the polar medium, isomerization of eugenol does not take place, and it acts as an antioxidant. However, in the non-polar medium, eugenol isomerizes to isoeugenol and displays a pro-oxidant effect. In the basic medium, eugenol isomerizing to isoeugenol undergoes degradation. Hence, to utilize the beneficial activity of eugenol, it should be present in a polar or acidic medium. It can be concluded from this review article that the structural form of any molecule plays a major role in utilizing its activity and is also dependent on the medium. Hence, the medium also performs a vital role in influencing the activity of any molecule.

Emulsions undergo an oxidation process because of the presence of water. The undesired phenomenon of autoxidation needs to be prevented as the lipidic fraction in the emulsion undergoes degradation. The surface active compounds so formed in the process disturb the stability of the emulsion. Accordingly, the characteristics of the emulsions are altered. This autoxidation process can be prevented by means of antioxidant. In the present study, a well known hydrophilic antioxidant, ascorbic acid, was examined at various concentrations to stabilize water-in-oil emulsion. The outcome showed that the concentration of a compound played an important role in determining its antioxidant or pro-oxidant effect.

It is now agreed that food plays a major role in the maintenance of good health. The awareness of consumers about diet-related health problems has increased. Hence, nowadays, preference is given to the natural food ingredients, which are expected to be safe and health promoting. Recently, many studies on health benefits associated with curcumin have been reported. In the present study, an attempt had been made to isolate curcumin from a mixture of curcuminoids by means of column chromatography technique. Further, the antioxidant activity of curcumin was studied in refined sunflower oil (RSFO). The activity was compared with that of mixture of curcuminoids in RSFO. The results showed that the other curcuminoids, i.e., demethoxycurcumin and bisdemethoxycurcumin had a profound effect on the activity of curcumin. Practical Applications Natural extracts have potential to stabilize unsaturated essential fatty acids effectively. It is well known that the presence of an active constituent in these natural extracts provides the property of antioxidant to the extract. The results revealed that the minor constituents had a profound effect on the activity of active constituent. The synergistic activity of all the constituents in an extract determines the resultant antioxidant activity of the extract.

Owing to the tendency of essential fatty acids (EFAs) to undergo autoxidation, their storage becomes a key problem. Generally, they are stabilized by synthetic antioxidants like TBHQ that are toxic in nature. Recently many studies were reported where these EFAs are stabilized by natural antioxidants. In the present study, curcuminoids and kalonji seeds ethanol extract (KEE) were used to stabilize these EFAs in refined sunflower oil (RSFO), water-in-oil (w/o) emulsion and butter like products (BLPs). In RSFO, though curcuminoids alone exerted pro-oxidant effect, KEE and curcuminoids showed synergistic antioxidant activity that was comparable to TBHQ. KEE exhibited good antioxidant activity in emulsions and BLPs, providing fine physical properties like slipping point, dropping point and spreadability. EFAs increased the nutritional value of BLPs and antioxidants added for their stabilization provided their medicinal benefits.

Neem oil is a natural pesticide and has excellent insecticidal properties. Hence, in this study the efforts have been made to formulate the Neem oil emulsions which would be used as agrochemicals. In order to formulate stable Neem oil emulsions, a binary emulsifier system of Hydol-6 (Polyoxyethylene Alkyl Ether-6 moles of ethylene oxids) and Hydol-10 (Polyoxyethylene Alkyl Ether-10 moles of ethylene oxids) were employed. Stability of Neem oil emulsions as a function of concentration of Neem oil, Hydol-6, Hydol-10, the amount of water, homogenization speed, and homogenization time was studied in depth. Apart from this, it was observed that the nature of water also affects the stability of the emulsions. The concentration of Neem oil in the stable emulsions was also found to exhibit the varying effects on the properties like dispersibility, spreading power, and droplet size of the emulsions. Larvasidal effects of stable Neem oil emulsions were examined.

Foamability and foam stability, emulsifying power, surface tension, and interfacial tension were investigated for different ratios of binary surfactant system of Arlacel‐165 (glyceryl stearate (and) PEG‐100 stearate) and Myrj‐59 (polyoxyethylene 100 stearate). Among all the ratios tested for their foaming power and foamabilty, the ratios 8:2, 5:5, 4:6, 2:8, and 1:9 of Arlacel‐165 and Myrj‐59 showed the best results. At these ratios, the foaming power and foamability was found to be 100%. The surfactants having foam stability more than 50% can be considered as metastable and those less than 50% are considered as low‐stability foams. In case of surface tension and interfacial tension property measurements, 8:2 and 9:1 showed the best results. At 8:2 and 9:1 of Arlacel‐165 and Myrj‐59, the surface tension was found to be 37.7 dynes/cm and 1.33 dynes/cm respectively at 30°C ambient temperature. Also, 7:3 of this binary mixture was found to exhibit the best emulsifying power among all the ratios tested. At 30°...