A global systematic review and meta-analysis on prevalence of the aflatoxin B1 contamination in olive oil.

Olive oil can be contaminated by fungal toxins; therefore, it is necessary to monitor the incidence of mycotoxins in this oil. In the present study, the pooled prevalence of detectable aflatoxin B1 (AFB1) in olive oil was evaluated using systematic review and meta-analysis approach from 1 January 1991 to 31 December 2020 (30 years study). The search was conducted via electronic databases involving Scopus, Web of Science, PubMed, Agris and Agricola. Synonyms were collected from combination of the MESH, Agrovoc and free text method. After screening and selection process of primary researches, full texts of eligible researches (46 studies) were evaluated and data of the nine studies as included researches were extracted. Random effect model was used to estimate the pooled prevalence of AFB1 in olive oil and weighing model of Dersimonian-Laired was applied. Summary measure of mycotoxin prevalence was estimated using Metaprop module of STATA and 95% confidence interval (CI) were calculated using the Binomial Exact Method. Pooled prevalence of AFB1 in olive oils were 32% (95% CI 8-56%) which means that 68% of olive oil were free of detectable contaminants of AFB1. Due to controversy over the results of primary studies, future researches and consequent subgroup analysis based on the main variables affecting the aflatoxins contamination in olive oil are recommended to achieve the conclusive results.

The Effect of Extraction by Pressing at Different Temperatures on Sesame Oil Quality Characteristics.

Sesame oil has been widely used in the daily diet due to its high nutritional value. Sesame oil is extracted at industrial scales and also in small scale by cold pressing at different temperatures. In this research, sesame oil was extracted by pressing at four temperatures, namely, 30 (control sample), 60, 90 and 120 °C, to evaluate its effects on the quality of extracted oils. Oil extraction yields were increased from 38 to 51% by increasing the pressing temperature. The highest amount of peroxide and acid values were related to the oil extracted at 120 °C. Tocopherols and total phenol content were reduced by the increasing the pressing temperature, and the highest amounts of these bioactive components were related to the control sample. The results of the fatty acids profile showed that the composition of oils extracted at different temperatures did not differ significantly (p > 0.05). The results of the present study give a clear picture about the effects of different pressing temperatures on the sesame oil quality and extraction yield, and can be useful in the extraction unit optimization.

A Study on the Specifications of Cold Pressed Colza Oil.

Cold pressed oil extraction is the preferred method for seeds with high contents of oil, such as colza. Generally speaking, expeller pressing is less complex, more cost efficient and safer than solvent extraction. Moreover, cold pressed oils retain their natural properties better. Cold pressed colza oil has been found to have numerous health benefits. This was an original and unique study conducted as part of the research for the international Codex standard for cold pressed fats and oils, and aims to examine the chemical properties of two varieties of Iranian colza seed, Hyola and Okapi. The studied factors included (a) chemical properties, and (b) physicochemical and quality characteristics. Based on our findings, both varieties of colza seeds in this study had satisfactory levels of oleic and linoleic acid, and no trans-fatty acids. Although both samples had good nutritional properties, the Hyola variety was higher in oleic acid, indicating better oxidative stability. Due to the considerable amounts of ß-sitosterol in both varieties, they may be effective in reducing cholesterol and preventing cancer.

Adequacy of the Measurement Capability of Fatty Acid Compositions and Sterol Profiles to Determine Authenticity of Milk Fat Through Formulation of Adulterated Butter.

In this research a comparison has been made between the fatty acid and sterol compositions of Iranian pure butter and three samples of adulterated butter. These samples were formulated using edible vegetable fats/oils with similar milk fat structures including palm olein, palm kernel and coconut oil to determine the authenticity of milk fat. The amount of vegetable fats/oils used in the formulation of the adulterated butter was 10%. The adulterated samples were formulated so that their fatty acid profiles were comforted with acceptable levels of pure butter as specified by the Iranian national standard. Based on the type of the vegetable oil/fat, fatty acids such as C4:0, C12:0 and C18:2 were used as indicators for the adulterated formulations. According to the standard method of ISO, the analysis was performed using gas chromatography. The cholesterol contents were 99.71% in pure butter (B1), and 97.61%, 98.48% and 97.98% of the total sterols in the samples adulterated with palm olein, palm kernel and coconut oil (B2, B3 and B4), respectively. Contents of the main phytosterol profiles such as ß-sitosterol, stigmasterol and campesterol were also determined. The ß-sitosterol content, as an indicator of phytosterols, was 0% in pure butter, and 1.81%, 1.67% and 2.16%, of the total sterols in the adulterated samples (B2, B3 and B4), respectively. Our findings indicate that fatty acid profiles are not an efficient indicator for butter authentication. Despite the increase in phytosterols and the reduction in cholesterol and with regard to the conformity of the sterol profiles of the edible fats/oils used in the formulations with Codex standards, lower cholesterol and higher phytosterols contents should have been observed. It can therefore be concluded that sterol measurement is insufficient to verify the authenticity of the milk fat in butter. It can therefore be concluded that sterol measurement is insufficient in verifying the authenticity of milk fat.