Seed oil and seed oil byproducts of common purslane (Portulaca oleracea L.): a new insight to plant-based sources rich in omega-3 fatty acids

In the present study, nutritional value, chemical composition and bioactive properties of purslane seeds, seed oils and seedcakes were examined. Data were analyzed by a one-way ANOVA, while means were compared with Tukey's HSD test. For seed oil extraction mechanical and ultrasound assisted methods were tested. Cold extraction methods (CE1 and CE2) resulted in higher oil yield (increased by 33.7% and 38.1%, respectively) comparing to hot extraction (HE) method. Seeds contained the highest amount of fats and energy (15.03 ± 0.06 g/100 g dry basis (db) and 459 ± 1 kcal/100 g db, respectively), while seedcakes from CE2 had the highest content in proteins and ash (31.20 ± 0.03 and 4.27 ± 0.06 g/100 g db, respectively). Seeds and seedcakes contained a balanced content of linoleic and α-linolenic acids (33.80–34.74% and 32.83–34.64%, respectively). HE and CE1 oils had slightly higher amounts of α-linolenic (39.67% and 39.57%, respectively) than linoleic acid (35.44% and 35.13%, respectively), whereas CE2 oils contained twice as much linoleic as α- linolenic acid (49.77% and 24.18%, respectively). In conclusion, the tested materials are good sources of omega- 6 and omega-3 fatty acids and proteins, while extraction method affected oil yield and fatty acids composition of seed oils.Agricultural Machinery, University of Thessaly, Greece, for providing the equipment and technical assistance for hot extraction of seed oils. We are also thankful to Mr. Tsolakidis C. (Giachanas - Cold Pressed Seed Oils S.A.; Evros, Greece) for providing the equipment and technical assistance for cold extraction of seed oils. The authors are also grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2019). L. Barros and A. Fernandes would like to thank the national funding by FCT, P.I., through the institutional scientific employment program-contract for their contracts.info:eu-repo/semantics/publishedVersio

Impact of Plant Density and Mepiquat Chloride on Growth, Yield, and Silymarin Content of Silybum marianum Grown under Mediterranean Semi-Arid Conditions

Milk thistle (Silybum marianum (L.) Gaertn.) is a promising new crop in the Mediterranean region. Its seeds contain silymarin, a complex of flavonolignans, which is widely used in the pharmaceutical industry, mainly to produce dietary supplements. To meet the increasing demand for milk thistle, the production and productivity of milk thistle should also be optimized by employing adequate cultivation practices. In the present study, a two-year field experiment was conducted to assess the effects of plant density and a plant growth regulator on milk thistle crop growth, seed yield, and silymarin accumulation under Mediterranean semi-arid conditions. Our results showed that plant density had a significant impact on milk thistle crop growth and seed yield. The main crop characteristics, such as height, aboveground biomass, and seed yield were greatest when plant density was the highest. Increased plant density significantly reduced the silymarin content only in 2018. In contrast, mepiquat chloride (MC) treatment did not affect the following traits: plant biomass, relative chlorophyll content, silymarin content, and production. Nevertheless, mepiquat chloride reduced the plant height by 7.9–14.8%, depending on the application rates and growth conditions. Moreover, the impact of climatic conditions on milk thistle production and quality was significant, since the lowest values of silymarin content and seed yield were recorded in the year with drought conditions during the period from March to May

Standing on unstable surface challenges postural control of tracking tasks and modulates neuromuscular adjustments specific to task complexity

Understanding the modulations of motor control in the presence of perturbations in task conditions of varying complexity is a key element towards the design of effective perturbation-based balance exercise programs. In this study we investigated the effect of mechanical perturbations, induced by an unstable surface, on muscle activation and visuo-postural coupling, when actively tracking target motion cues of different complexity. Four postural tasks following a visual oscillating target of varying target complexity (periodic-sinusoidal vs. chaotic-Lorenz) and surface (stable-floor vs. unstable-foam) were performed. The electromyographic activity of the main plantarflexor and dorsiflexor muscles was captured. The coupling between sway and target was assessed through spectral analysis and the system’s local dynamic stability through the short-term maximum Lyapunov exponent. We found that external perturbations increased local instability and deteriorated visuo-motor coupling. Visuo-motor deterioration was greater for the chaotic target, implying that the effect of the induced perturbations depends on target complexity. There was a modulation of the neuromotor system towards amplification of muscle activity and coactivation to compensate surface-related perturbations and to ensure robust motor control. Our findings provide evidence that, in the presence of perturbations, target complexity induces specific modulations in the neuromotor system while controlling balance and posture.Peer Reviewe

Neuromuscular differences between prepubescents boys and adult men during drop jump

The purpose of the present study was to determine the lower extremities biomechanical differences between prepubescent and adult males during drop jumps (DJs). Twenty-four untrained males (12 prepubescents, 12 adults) performed DJs from 20 cm height. Kinematics of the lower extremities were captured, in addition with vertical ground reaction forces (vGRFs) and EMG activity of the gastrocnemius medialis (GM), soleus (SOL) and tibialis anterior (TA) muscles. The results showed that men jumped higher, as expected, but their knees were more flexed prior to landing, and their preactivation level was higher and longer in duration compared to prepubescent boys. During landing, men had shorter contact times, lower vGRF normalized to body mass, and less maximal knee joint flexion. Regarding EMG activity men presented higher stretch reflex and higher EMG activity during the braking phase but the level of coactivation (TA to GM + SOL ratio) was lower. It is seems that pre-landing and landing patterns during a complex task such as DJ are affected by physical development. There are indications that men had higher performance in a DJ than prepubescent boys because they activated more effectively their muscles during the preactivation and braking phase. The above-mentioned data support the hypothesis that prepubescent boys might be inferior in optimal regulation of their muscle-tendon unit stiffness