In this paper, the occurrence of secoiridoid aglycones via degradation of phenolic glucosides which have strong effects on commercial, nutritional, and sensory properties of olive oil is studied. The experiment consists in the sonication treatment of Chemlali and Memecik cvs. olive paste three times for 4, 8, and 10 min. This kind of approach has never been used in determining the partition and degradation of phenolics during extraction. Concerning phenolic content present in Chemlali olive oil extracted from whole olives, no significant differences are found after 10 min of treatment using ultrasound apparatus, whereas a rise of more than 60% is detected if olive paste without stones is used. On the other hand, the total phenolic content of Memecik cv. increases positively with the increasing time of treatment. Throughout this report, it is noted that enzymatic activities are affected by ultrasound treatment. Practical Applications: The results of this study will be useful in modification of present processes or development of new processes with the aim of protecting and improving the phenolic composition of olive oil. To the best of the authors’ knowledge, this kind of systematic approach has never been used in determining the partition and degradation of phenolics during extraction. It is believed that describing the effects of high‐power ultrasound applications on olive paste before malaxation will exhibit possible benefits for the future of olive processing technology. The optimization of olive oil extraction parameters with proper adjustments in such a way that the quality of the product is highly increased is an important issue. The effect of ultrasound technology parameters is investigated from the point of phenolic compounds by searching their relation to enzymes in Chemlali and Memecik cvs. olive paste. In addition, the effects of stone removal during extraction are also studied in terms of enzymes in Chemlali and Memecik cvs. olive paste and phenols in olive oil.

Wheatgrass juice is mainly derived from the common wheat Triticum aestivum L. The present study focused on the analysis of the potential of different perennial turfgrass species in grass juice production by determining certain compositional characteristics. The effects of fertilisers on the plants and the cutting time on some chemical constituents and antioxidant potential of grass juices were addressed. The juices from the different species of grasses, such as T. durum, T. aestivum, Lolium perenne L., Festuca arundinacea Schreb. were obtained by pressing. DPPH (1, 1diphenyl-2-picrylhydrazyl) radical scavenging activity, elemental composition, total chlorophylls, total carotenes, tocopherols, vitamin C, total phenols, viscosity and the colour profiles of the grass juice samples were analysed. Water-soluble dry matter, protein, total phenols, flavonoids and vitamin E (especially Durum cultivar) content were found to be higher in the juices of Triticum species as compared to the other grasses. Turfgrass species demonstrated higher concentrations of oil (in grass), vitamin C (unfertilised samples), chlorophyll (except L. perenne local) and major elements. The pressing of turfgrass was an easy process. Such perennial grass varieties have advantages over the Triticum species in terms of having higher concentrations of vitamin C (unfertilised samples) and major elements. The results of sensory analysis suggested that L. perenne (cultivar) is the most promising cultivar in terms of obtaining pressed grass juice.

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Research background. Utilization of wheat germ (WG) and wheat germ oil (WGO) is limited due to high enzymatic activity and unsaturated fatty acids and therefore stabilization techniques are needed to overcome this problem. Experimental approach. In this study, the effects of stabilization methods (dry convective oven heating at 90 and 160 oC and microwave radiation under 180 W and 360 W output power, and steaming by autoclave) on both WG and WGO were evaluated. Results and conclusions. Steaming caused the most dramatic changes on lipoxygenase, free fatty acids (FFA), DPPH radical scavenging activity, tocopherols and tocotrienols. The lowest peroxide values (PVs) were measured in oils of convectional heating (160 oC) and steaming treatments which were performed at temperatures above 100 oC. However, para-anisidine values (pAVs) of samples treated at higher temperatures were considerably greater than those of stabilized at lower temperatures. Oven heating at 160 oC was also one of the most effective treatments on inactivation of lipoxygenase coming after steaming. Steaming also induced a significant reduction in total tocopherols which was directly associated with the greater lost in β-tocopherol content. On the contrary γ- and δ-tocopherols and tocotrienol homologs were abundant with higher amounts in steam applied samples. α-Tocopherol and γ-tocotrienol were the most resistant isomers to stabilization processes. Novelty and scientific contribution. This study shows that the high temperature oven heating method, which is widely used in the industry for thermal stabilization of wheat germ, does not provide an advantage in oxidative stability compared to steaming and microwave applications. Steaming delayed oxidation in germ, while further inhibiting lipoxygenase activity. Moreover, tocotrienols were more conservable. In industrial application, low power in microwave (180 W instead of 360 W), lower temperature in oven heating (90 instead of 160 oC) would be preferable.

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