The Stability of Refined Rapeseed Oil Fortified by Cold-Pressed and Essential Black Cumin Oils under a Heating Treatment

The Effect of High-Temperature Heating on Amounts of Bioactive Compounds and Antiradical Properties of Refined Rapeseed Oil Blended with Rapeseed, Coriander and Apricot Cold-Pressed Oils

Cold-pressed oils are rich sources of bioactive substances, which may protect triacylglycerols from degradation during frying. Nevertheless, these substances may decompose under high temperature. This work considers the content of bioactive substances in blends and their changes during high-temperature heating. Blends of refined rapeseed oil with 5% or 25% in one of three cold-pressed oils (rapeseed, coriander and apricot) were heated at 170 or 200 °C in a thin layer on a pan. All non-heated blends and cold-pressed oils were tested for fatty acid profile, content and composition of phytosterols, tocochromanols, chlorophyll and radical scavenging activity (RSA) analyzed by 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays. Moreover, the stability of phytosterols, tocochromanols, DPPH and ABTS values was determined in heated blends. All tocochromanols were lost during the heating process, in particular, at 200 °C. However, there were some differences between homologues. α-Tocopherol and δ-tocopherol were the most thermolabile and the most stable, respectively. Phytosterols were characterized by very high stability at both temperatures. We observed relationships between ABTS and DPPH values and contents of total tocochromanols and α-tocopherol. The obtained results may be useful in designing a new type of fried food with improved health properties and it may be the basis for further research on this topic.

Improving the functionality of virgin and cold-pressed edible vegetable oils: Oxidative stability, sensory acceptability and safety challenges

In recent years, there has been a growing demand for minimally processed foods that offer health benefits and premium sensory characteristics. This trend has led to increased consumption of virgin (VOs) and cold-pressed (CPOs) oils, which are rich sources of bioactive substances. To meet consumer needs for new oil products conferring multi-functional properties over a longer storage period, the scientific community has been revisiting traditional enrichment practices while exploring novel fortification technologies. In the last four years, the interest has been growing faster; an ascending number of annually published studies are about the addition of different plant materials, agri-food by-products, or wastes (intact or extracts) to VOs and CPOs using traditional or innovative fortification processes. Considering this trend, the present review aims to provide an overview and summarize the key findings from relevant papers that were retrieved from extensively searched databases. Our meta-analysis focuses on exposing the most recent trends regarding the exploitation of VOs and CPOs as substrates, the fortification agents and their form of use, as well as the fortification technologies employed. The review critically discusses possible health claim and labeling issues and highlights some chemical and microbial safety concerns along with authenticity issues and gaps in quality specifications that manufacturers have yet to address. All these aspects are examined from the perspective of developing new oil products with well-balanced techno-, senso- and bio-functional characteristics.

Physicochemical and Morphological Study of the Saccharomyces cerevisiae Cell-Based Microcapsules with Novel Cold-Pressed Oil Blends

Vegetable oils rich in polyunsaturated fatty acids are a valuable component of the human diet. Properly composed oil blends are characterized by a 5:1 ratio of ω6/ω3 fatty acids, which is favorable from a nutritional point of view. Unfortunately, their composition makes them difficult to use in food production, as they are susceptible to oxidation and are often characterized by a strong smell. Encapsulation in yeast cells is a possible solution to these problems. This paper is a report on the use of native and autolyzed yeast in the encapsulation of oils. The fatty acid profile, encapsulation efficiency, morphology of the capsules obtained, and thermal behavior were assessed. Fourier transform infrared analysis and low-field nuclear magnetic resonance relaxation time measurements were also performed. The process of yeast autolysis changed the structure of the yeast cell membranes and improved the loading capacity. Lower encapsulation yield was recorded for capsules made from native yeast; the autolysis process significantly increased the value of this parameter. It was observed that NY-based YBMCs are characterized by a high degree of aggregation, which may adversely affect their stability. The average size of the AY capsules for each of the three oil blends was two times smaller than the NY-based capsules. The encapsulation of oils in yeast cells, especially those subjected to the autolysis process, ensured better oxidative stability, as determined by DSC, compared to fresh blends of vegetable oils. From LF NMR analysis of the relaxation times, it was shown that the encapsulation process affects both spin-lattice T1 and spin-spin T2* relaxation times. The T1 time values of the YBMCs decreased relative to the yeast empty cells, and the T2* time was significantly extended. On the basis of the obtained results, it has been proven that highly unsaturated oils can be used as an ingredient in the preparation of functional food via protection through yeast cell encapsulation.