Effect of

Improving the oxidative stability of virgin olive oil using microformulated vitamin-C

This study aims to improve the oxidative stability of olive oil using microformulated vitamin-C (Vit-C). The microemulsion containing 10,000 µg/ml Vit-C with a droplet size of 1,000 ± 68 nm was first prepared. Free radical scavenging of olive oil and olive oil containing blank microemulsion, different amounts of formulated Vit-C (100-500 µg/ml), and TBHQ (100 and 200 µg/ml as a standard antioxidant) was around 90% during 21 days of incubation at 60°C. The oxidative stability of the mentioned samples during incubation was investigated using the rancimat test, and their quality criteria analysis was studied by peroxide and the acid values. Results showed that the sample's acid value containing 500 µg/ml of Vit-C did not show significant differences (p < .05) with samples containing TBHQ. However, samples containing TBHQ's peroxide value were significant (p < .05) lower than samples containing 500 µg/ml of Vit-C. Furthermore, the induction time of samples containing 500 µg/ml of Vit-C was significantly (p < .05) higher than other treatments during incubation. Thus, the prepared microemulsion could be used as a natural antioxidant in the oil industry instead of harmful synthetic TBHQ.

Common Kilka oil and its primary and secondary oxidative dynamics stabilized by different variants of clove essential oil

The objective of this study was to investigate the properties of clove essential oil extracted by different microwave-assisted methods and to evaluate its effects on the stability of common Kilka oil. Each of these methods was hypothesized to yield a clove essential oil that would have a distinguishable composition and effect when added to common Kilka oil by maintaining its oxidative stability. The oxidation of common Kilka oil was examined by accelerated oxidation using the active oxygen method and Rancimat test. The clove essential oil extracted by microwave-assisted hydrodistillation showed the highest induction period according to the active oxygen method (16.56 h) and the Rancimat induction period (3.64 h) in common Kilka oil and its antioxidant activity was comparable to that of BHT (16.59 h and 4.34 h, respectively) and tocopheryl acetate (16.30 h and 4.02 h, respectively). Furthermore, the microwaveassisted hydrodistillation method resulted in the amount of eugenol that exhibited the highest antioxidant capacity for preserving PUFA in common Kilka oil. Ultimately, clove essential oil can become an efficient natural antioxidant for the oxidative stability of common Kilka oil.

Evolution of Flavors in Extra Virgin Olive Oil Shelf-Life

Extra virgin olive oil (EVOO) is one of the most distinctive ingredients of the Mediterranean diet. There are many properties related to this golden ingredient, from supreme organoleptic characteristics to benefits for human health. EVOO contains in its composition molecules capable of exerting bioactivities such as cardio protection, antioxidant, anti-inflammatory, antidiabetic, and anticancer activity, among others, mainly caused by unsaturated fatty acids and certain minor compounds such as tocopherols or phenolic compounds. EVOO is considered the highest quality vegetable oil, which also implies a high sensory quality. The organoleptic properties related to the flavor of this valued product are also due to the presence of a series of compounds in its composition, mainly some carbonyl compounds found in the volatile fraction, although some minor compounds such as phenolic compounds also contribute. However, these properties are greatly affected by the incidence of certain factors, both intrinsic, such as the olive variety, and extrinsic, such as the growing conditions, so that each EVOO has a particular flavor. Furthermore, these flavors are susceptible to change under the influence of other factors throughout the oil's shelf-life, such as oxidation or temperature. This work offers a description of some of the most remarkable compounds responsible for EVOO's unique flavor and aroma, the factors affecting them, the mechanism that lead to the degradation of EVOO, and how flavors can be altered during the shelf-life of the oil, as well as several strategies suggested for the preservation of this flavor, on which the quality of the product also depends.

Extraction of Essential Oils from Medicinal Plants and their Utilization as Food Antioxidants

BACKGROUND

The use of essential oils is receiving increasing attention worldwide, as these oils are good sources of several bioactive compounds. Nowadays essential oils are preferred over synthetic preservatives thanks to their antioxidant and antimicrobial properties. Several studies highlight the beneficial effect of essential oils extracted from medicinal plants to cure human diseases such as hypertension, diabetes, or obesity. However, to preserve their bioactivity, the use of appropriate extraction technologies is required.

METHODS

The present review aims to describe the studies published so far on the essential oils focusing on their sources and chemical composition, the technologies used for their recovery and their application as antioxidants in food products.

RESULTS

The review has been structured in three parts. In the first part, the main compounds present in essential oils extracted from medicinal plants have been listed and described. In the second part, the most important technologies used for extraction and distillation, have been presented. In detail, conventional methods have been described and compared with innovative and green technologies. Finally, in the last part, the studies related to the application of essential oils as antioxidants in food products have been reviewed and the main findings discussed in detail.

CONCLUSION

In summary, an overview of the aforementioned subjects is presented by discussing the results of the most recent published studies.

A Concise Overview of Phytochemistry, Pharmacology and Clinical Aspects of Persian Cumin; Bunium persicum (Boiss.) B.Fedtsch

Bunium persicum is one of the most medically and economically important species of the Apiaceae family. Despite a variety of phytochemical and experimental research on this species, there is no considerable update on all related outcomes. Accordingly, current work compiles an overview of Cumin's phytochemical and pharmacological activities. Papers related to phytochemistry, pharmacology and clinical properties of B. persicum were filtered from databases as PubMed, ScienceDirect and Scopus with the term "Bunium persicum" till 15th May 2020. Genetic, pure pharmaceutical and agriculture papers were excluded. Moreover, traditional applications of this herb in Persian medicine were studied and included. In all, 54 papers reporting the compositions, Anticonvulsant, antinociceptive, anti-inflammatory, antioxidant, anti-glycation, antidiarrhea, anti-hematotoxic, anti-toxoplasmosis, hypoglycemic, larvicidal, scolicidal, anticholinergic and antihistaminic activities of B. persicum as well as reducing and stabilizing effects in nanoparticles. Three clinical trials have also been conducted on B. persicum. There are also numerous effects, cited in traditional manuscripts such as gastroprotective, kidney tonic, slimming activity and antidote for poisons. The most dominant chemical composition of Cumin is the essential oil, responsible for various potent antimicrobial and antifungal activities. The herb also contains phenolic and flavonoid compounds that reflect the antioxidant and anti-inflammatory activities. Many of the experimental and pharmacological studies on B. persicum have traces in traditional manuscripts. There are also medical aspects that have not yet been evaluated. Despite various experimental investigations, lack of extensive clinical studies, which is currently limited to few trials on remarked activities of B. persicum is still remained to be covered.

Improving oxidative stability of olive oil: Incorporation of Spirulina and evaluation of its synergism with citric acid

The effects of different Spirulina concentrations used alone and in combination with citric acid on the oxidative stability of olive oil were assessed. The amounts of primary and secondary oxidation products produced in Spirulina samples were lower than that of the control. The improved oxidative stability indices of Spirulina samples with and without citric acid were in the range of 85.20–94.47% and 258.10–260.21%, respectively. In comparison with the control, Spirulina samples manifested significantly higher carotenoid and chlorophyll contents at the beginning and end of the storage period. The presence of these bioactive compounds results from the presence of Spirulina in the medium and can thus retard the oxidation of olive oil. A higher oxidative stability was reached using BHT in comparison with Spirulina samples. Furthermore, no synergistic action was observed in possible connections between citric acid and Spirulina. In conclusion, Spirulina can enhance oxidative stability and improve the shelf life of olive oil.