Egg yolk was partially replaced (0, 25, 50, 75, and 100%) with octenyl succinic anhydride (DSA)-modified potato starch in a reduced-fat mayonnaise formulation to curtail the problems associated with high cholesterol and induced allergic reactions. The physicochemical properties included parameters such as: pH, fat content, and emulsion stability of the formulations analyzed. The samples with 75% and 100% egg yolk substitute showed the maximum emulsion stability (>95% after two of months storage), and they were selected according to cholesterol content, particle size distributions, dynamic rheological properties, microstructure, and sensory characteristic. A significant reduction (84-97%) in the cholesterol content was observed in the selected samples. Particle size analysis showed that by increasing the amount of DSA starch, the oil droplets with the peak size of 70 µm engulfed by this compound became larger. The rheological tests elucidated that in the absence of egg yolk, DSA starch may not result in a final product with consistent texture and that the best ratio of the two emulsifiers (DSA starch/egg yolk) to produce stable reduced-fat, low cholesterol mayonnaise is 75/25. The microscopic images confirmed the formation of a stable cohesive layer of starch surrounding the oil droplets emulsified in the samples selected.Keywords: octenyl succinic anhydride; cholesterol; mayonnaise; particle size distributions; rheological characteristics; microstructure.Practical Application: The egg yolk has been partially replaced (0, 25, 50, 75,100%) by octenyl succinic anhydride (DSA)-modified potato starch in a reduced-fat mayonnaise formulation. The pH, fat content, cholesterol content and emulsion stability, particle size distributions, dynamic rheology, microstructure properties of the formulations were analyzed and the results indicated that 100% substitution of egg yolk may not be desirable because of large droplet size, low consistency and poor sensory scores. The best ratio of the two emulsifiers to produce stable reduced-fat, low cholesterol mayonnaise would be 75/25.

Twenty seven Iranian olive oil samples were collected from different provinces to evaluate fatty acids and sterol compositions. The samples were collected from different geographical locations that varied in altitude, temperature, humidity and rain fall. The sample collected from the northern part of Iran by the Caspian Sea had higher oleic acid [G 2 sample (75.98%)] and lower linoleic acid [Go 5 sample (6.5%)] and palmitic acid [G 2 sample (10.78%)] concentrations than samples from the southern part of the country such as F 1 whose contents of C16:0, C18:1 and C18:2 were 15.27, 62.73 and 16.09%, respectively, in the southern part, the climate is dry and the temperature variation is wider and the elevation is 1,488 m. The results indicated that oleic acid was the predominant fatty acid with 62.7% for F 1 sample in the warmer climate at the south of Iran to 76.0% for G 2 sample in the cooler climate in the north of Iran. According to the results, the highest content of b-sitosterol was 87% related to samples G 9 and Z 3 from the north of Iran and the lowest content was 69.95% related to sample F 1-24 from the south of Iran. Clustering techniques such as principal component analysis and hierarchical cluster analysis were carried out on olive composition data to show similarities and discrimination between samples as a function of the cultivation zone. The two methods applied clearly showed the effect of growing regions on the distribution of the olive oil samples in the high dimensional space created by fatty acid and sterol compositions.

For evaluation of the authenticity of Iranian olive oil, samples from many Iranian olive oil producers especially north of Iran in the production year 2007 were collected. The fatty acid and triacylglycerol compositions were measured. The most recent calculation methods including DECN the difference between the actual and theoretical ECN42 (equivalent carbon number), triglyceride content and R of olive oils according to IOOC methods were applied. On the basis of our results, we were able to classify the olive oils into the extra virgin, virgin olive and olive oil categories. The important fatty acids are oleic, palmitic and linoleic acids and their main triacylglycerols are OOO, POO, OOL, PLO, SOS plus POP, and OLL, respectively. On the basis of the triacylglycerol results, experimental ECN48, ECN46, ECN50, ECN44 and ECN42 were obtained. By using the fatty acids results and a computer program, the theoretical ECN42 and ECN44 were calculated. Then R values, being the ratio of r ECN42/r ECN44 for authenticity of all olive oils and DECN for determining categories of olive oils, were defined. The results of olive oil samples were in the accepted limits of Codex and IOOC. Finally we suggest that the R and DECN can be used in identification of adulteration of olive oils and also they are useful from the point of view of authenticity and classification.

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