Journal of the American Oil Chemists' Society

Olive (Olea europaea cv. “Picual”) fruits were stored under five different storage conditions (°C/%CO2/%O2; ambient; 5:0:21; 5:3:20; 5:3:5; and 5:<1:5) to determine their influence on the chemical and sensorial quality of oil extracted from the olives at the end of the storage period. Results showed that storage of fruits at 5°C prevented the fast alteration that is produced in oils extracted from fruits stored at ambient temperatures. The use of controlled atmosphere at 5°C with 3% CO2 and/or 5% O2 did not present clear advantages on acidity, peroxide value, K270 and K232 coefficients, stability and sensorial quality. Cooling of fruit keeps physical, chemical and sensorial characteristics of oil below maximum established values for the period of time assayed (60 d).

Excised Lincoln soybean stems bearing pods and leaves were supplied with C14 labeled-sucrose for brief periods, and the subsequent appearance of radio-activity in the different fatty acids was observed up to 18 days. The individual fatty acids were separated as their 2,4-dinitrobenzenesulfenyl chloride derivatives and the specific activity of the different fractions were determined. Radioactivity appeared in the fatty acids in the following order: oleic, saturated, linoleic, linolenic. Consistent presence of highest specific activity in the oleic acid fraction indicated that oleic may be converted to the other acids, at least to some extent.

Diacylglycerols (DAG) are important intermediates in lipase-catalyzed interesterification, but a high DAG concentration in the reaction mixture results in a high DAG content in the final product. We have previously shown that a high DAG concentration in the reaction mixture increases the degree of acyl migration, thus adding to the formation of by-products. In the present study we examined the influence of water content, reaction temperature, enzyme load, substrate molar ratio (oil/capric acid), and reaction time on the formation of DAG in batch reactors. We used response surface methodology (RSM) to minimize the numbers of experiments. The DAG content of the product was dependent on all parameters examined except reaction time. DAG formation increased with increasing water content, enzyme load, reaction temperature, and substrate ratio. The content of sn-1,3-DAG was higher than that of sn-1,2-DAG under all conditions tested, and the ratio between the contents of the former compounds and the latter increased with increasing temperature and reaction time. The water content, enzyme load, and substrate ratio had no significant effect on this ratio. The DAG content was positively correlated with both the incorporation of acyl donors and the degree of acyl migration.

The AOCS official method for the determination of total polar compounds in deep-frying oils is often used to estimate frying oil degradation. It can be accurate and reliable, but with sacrifices of time and expense. The TPM VERI-FRY® PRO (Libra Technologies, Inc., Metuchen, NJ) quick test provides a quick and easy way to measure polar compounds in frying oils. The modified quick test measured at 490 nm has a good correlation with the AOCS official method (r=0.975, P<0.001) and provides a good estimate of polar compound accumulation in oils over 80 h of deep-frying. Using the quick test to measure polar compounds is fast, convenient, economical and reliable.

Study on interrelationship between oil, protein, and free gossypol in cottonseed kernels of 97 varieties is reported. Relationship between these properties was studied for each botanical species separately, as well as for all the varieties together. Protein and oil were negatively correlated. The correlation coefficients (γ) were significant at the 1% level in the case ofGossypium arboreum, Gossypium hirsutum, andGossypium barbandense, as well as for all the varieties combined. In the case ofGossypium herbaceum varieties, γ was significant at 5% level. No correlation was found between oil and free gossypol. Protein and free gossypol were negatively correlated. The correlation coefficients were significant at the 1% level in the case ofG. hirsutum, G. barbadense, and all the varieties combined, while it was significant at 5% in the case ofG. herbaceum varieties.