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Abstract: Bull M. longissimus dorsi (n=94) categorised into high (n=28), intermediate (n=14) and low (n=52) ultimate pH (pHu) were aged at −1.5°C for 28days. Shear force was higher and more variable (p<0.05) in intermediate pHu samples during ageing. Titin, filamin and desmin degradation was also less extensive in intermediate pHu samples compared to the other two pH categories. The extent of the decline of HSP20, HSP27 and αβ-crystallin concentrations during post mortem ageing was pHu related such that high pHu meat maintained the highest concentration of small heat shock proteins followed by intermediate and low pHu meat. μ-Calpain autolysis was slowest in intermediate pHu and cathepsin B activities remained consistently low during ageing in this group (p<0.05). Meat toughness in the intermediate pHu group may be attributed to the combination of a larger pool of sHSP with a sub-optimal cathepsin B activity and intermediary μ-calpain activities. [Copyright &y& Elsevier]

Previous clinical studies indicate that monoamine oxidase-B (MAO-B) inhibition by blackcurrants must be predominantly attributed to bioactives other than anthocyanins. In this natural products discovery study, MAO-A/B inhibitory phytochemicals were isolated from blackcurrants, and a double-blind crossover study investigated the efficacy of freeze-dried whole-fruit blackcurrant powder in inhibiting MAO-B compared with blackcurrant juice in healthy adults. Platelet MAO-B inhibition was comparable between powder (89% ± 6) and juice (91% ± 4), and it was positively correlated with MAO-modulated plasma catecholamines, subjective alertness, and reduced mental fatigue, assessed using the Bond-Lader questionnaire. Sarmentosin, a nitrile glycoside, and its hydroxycinnamoyl esters were identified as novel MAO-A/B inhibitors from blackcurrant in vitro , and sarmentosin was demonstrated to inhibit platelet MAO-B activity in vivo . These findings confirm sarmentosin as the primary bioactive for MAO-A/B inhibition in blackcurrants, as well as its bioavailability and stability during freeze-drying, and suggest that consuming blackcurrant powder and juice may positively affect mood in healthy adults.

Kiwifruit (KF) has shown neuroprotective potential in cell-based and rodent models by augmenting the capacity of endogenous antioxidant systems. This study aimed to determine whether KF consumption modulates the antioxidant capacity of plasma and brain tissue in growing pigs. Eighteen male pigs were divided equally into three groups: (1) bread, (2) bread + Actinidia deliciosa cv. 'Hayward' (green-fleshed), and (3) bread + A. chinensis cv. 'Hort16A' (yellow-fleshed). Following consumption of the diets for eight days, plasma and brain tissue (brain stem, corpus striatum, hippocampus, and prefrontal cortex) were collected and measured for biomarkers of antioxidant capacity, enzyme activity, and protein expression assessments. Green KF significantly increased ferric-reducing antioxidant potential (FRAP) in plasma and all brain regions compared with the bread-only diet. Gold KF increased plasma ascorbate concentration and trended towards reducing acetylcholinesterase activity in the brain compared with the bread-only diet. Pearson correlation analysis revealed a significant positive correlation between FRAP in the brain stem, prefrontal cortex, and hippocampus with the total polyphenol concentration of dietary interventions. These findings provide exploratory evidence for the benefits of KF constituents in augmenting the brain's antioxidant capacity that may support neurological homeostasis during oxidative stress.

Unaccustomed eccentric exercise results in muscle damage limiting physical performance for several days. This study investigated if Greenshell™ mussel (GSM) powder consumption expedited muscle recovery from eccentric exercise-induced muscle damage (EIMD). Methods: Twenty untrained adult men were recruited into a double-blind, placebo-controlled, cross-over study and were randomly assigned to receive the GSM powder or placebo treatment first. Participants consumed their allocated intervention for four weeks then completed a bench-stepping exercise that induced muscle damage to the eccentrically exercised leg. Muscle function, soreness and biomarkers of muscle damage, oxidative stress and inflammation were measured before exercise, immediately after exercise and 24, 48 and 72 h post exercise. GSM powder promoted muscle function recovery, significantly improving ( p < 0.05) isometric and concentric peak torque at 48 h and 72 h post exercise, respectively. Participants on the GSM treatment had faster dissipation of soreness, with significant treatment × time interactions for affective ( p = 0.007) and Visual Analogue Scale-assessed pain ( p = 0.018). At 72 h, plasma creatine kinase concentrations in the GSM group were lower ( p < 0.05) compared with the placebo group. This study provides evidence for GSM powder being effective in supporting muscle recovery from EIMD.

Introduction: Contusion injuries are common in sport, but our knowledge of the responses to injury primarily come from animal studies and research using eccentric exercise. Therefore, the aim of this study was to develop a model of contusion injury in human participants and, additionally, investigate and compare physiological responses to four impact loads., Methods: Thirty-two males were exposed to a single impact of either 4.2, 5.2, 6.2 or 7.2kg, dropped from 67 cm, on to the vastus lateralis of one leg. Maximum voluntary and electrically induced quadriceps force, and pressure pain threshold were measured, and blood sampling carried out, prior to and 30min, 24, 48 and 72h post-impact. Magnetic resonance imaging was carried out 24h post-impact to quantify oedema., Results: Despite impact force with 7.2kg (1681.4 ± 235.6 N) not being different to 6.2kg (1690.7 ± 117.6 N), 7.2kg resulted in greater volume of oedema, voluntary force loss, pain and elevations in creatine kinase than the other loads. Although electrically induced force changed over time, post-hoc analysis failed to identify any changes. Interleukin-6 and prostaglandin-E2 did not change over time for any of the loads. Significant correlations were found between oedema volume, pressure pain threshold and maximum voluntary contraction force., Conclusions: This is the first experimental study to investigate traumatic loading of skeletal muscle and the subsequent physiological responses associated with contusion injuries in humans. The absence of immediate elevations in creatine kinase and changes in electrically induced force suggest impact, with forces similar to those experienced in contact sport, does not cause significant, direct damage to skeletal muscle. However, the relationship between oedema volume, changes in pressure pain threshold and maximum voluntary contraction force suggests central inhibition plays a role in contusion-related muscle dysfunction., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2022 Barnes et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Objectives: We examined the acute effects of anthocyanin-rich New Zealand blackcurrant extract and a placebo on hemodynamics during 120 min of sedentary sitting in healthy males. Additionally, we investigated whether changes in resting hemodynamics altered repeated isometric hand-grip exercise performance and post exercise forearm blood flow (FBF). Methods: Ten healthy males completed two trials during which they ingested either blackcurrant extract (1.87 mg total anthocyanins/kg bodyweight) or placebo powder. Heart rate, blood pressure and forearm blood flow were measured, and venous blood was sampled, prior to and 30, 60, 90 and 120 min-post ingestion. Participants remained seated for the duration of each trial. At 120 min post-ingestion participants completed as many repetitions of isometric hand-grip contractions as possible. Results: Heart rate, blood pressure and mean arterial pressure changed over time (all p < 0.001) but did not differ between treatments. A treatment x time interaction for FBF ( p = 0.025) and forearm vascular resistance (FVR) ( p = 0.002) was found. No difference in the number of isometric hand-grip contractions was observed between treatments ( p = 0.68) nor was there any treatment x time interaction in post-exercise FBF ( p = 0.997). Plasma endothelin-1 ( p = 0.023) and nitrate ( p = 0.047) changed over time but did not differ between treatments (both p > 0.1). Plasma nitrite did not change over time ( p = 0.732) or differ between treatments ( p = 0.373). Conclusion: This study demonstrated that acute ingestion of a single dose of blackcurrant extract maintained FBF and FVR during an extended period of sitting; however, this did not influence exercise performance during hand-grip exercise., (Copyright © 2020 Barnes, Perry, Hurst and Lomiwes.)

Background: Regular exercise is essential to a healthy lifestyle but evokes an oxidative and inflammatory stress. Depending upon its intensity and duration this can result in either beneficial adaptive changes or underlying tissue damage that impacts upon long-term health and individual sporting training schedules. Functional foods containing plant bioactives have potential to support exercise through management of the detrimental aspects of exercise and complement ergonomic adaptive benefits. Aim: Previously we reported that a single consumption of a 3.2 mg/kg New Zealand blackcurrant anthocyanin-rich extract (BAE) 1 h before a 30 min rowing exercise attenuated moderate exercise-mediated oxidative stress and supported innate immunity. Here we evaluate whether the efficacy of a single consumption of BAE 1 h prior to exercise is changed after extended daily BAE consumption for 5 weeks. Results: On week 1, a single consumption of BAE 1 h before a 30 min row mediated a significant ( p < 0.05) 46% reduction in post-exercise-induced malondialdehyde (MDA) by 2 h compared to a 30% reduction in the placebo group. Similar efficacy was observed 5 weeks later after daily consumption of BAE. In addition, daily BAE consumption for 5 weeks improved the efficacy to (a) resolve acute inflammation, and (b) increased plasma IL-10, salivary beta-defensin 2 (BD2) and secretory IgA. Although no change in plasma antioxidant capacity was detected, a significant ( p < 0.009) positive correlation between plasma IL-10 and plasma antioxidant capacity ( R 2 = 0.35) was observed on week 6 after 5 week BAE consumption suggesting IL-10 influences antioxidant properties. Using a differentiated myotubule cell-line revealed that whilst IL-10 had no direct antioxidant neutralizing action, longer-term exposure (24 h) attenuated 2,2'-Azobis(2-amidinopropane) dihydrochloride (AAPH)-induced myotubule oxidative stress, supporting a putative role for IL-10 in the modulation of cellular antioxidant systems. Conclusions: Daily consumption of BAE for 5 weeks serves to enhance the exercise recovery effectiveness of a single consumption of BAE and promotes beneficial/protective antioxidant/anti-inflammatory cellular events that facilitate exercise recovery., (Copyright © 2020 Hurst, Lyall, Wells, Sawyer, Lomiwes, Ngametua and Hurst.)

Intermittent fasting improves metabolic and cardiac health. However, increased hunger towards the end of the fasting period may affect compliance and limit its application. Our aim was to determine the effect of anorexigenic agent co-therapy on subjective ratings of appetite during the 16-24 h period of a day-long water-only intermittent fast. Thirty adult men were recruited and required to fast for 24 h from 18:00 h to 18:00 h on the same day of the week for three subsequent weeks. Treatments of either a placebo or one of two doses (high dose; HD: 250 mg or low dose; LD: 100 mg) of a bitter hops-based appetite suppressant (Amarasate®) were given twice per day at 16 and 20 h into the fast. From 18-24 h of the 24 h fast, both the HD and LD treatment groups exhibited a statistically significant ( p < 0.05) > 10% reduction in hunger. Additionally, the expected lunchtime increase in hunger that was present in the placebo group (12:00 h) was absent in both the HD and LD groups. These data suggest that appetite suppressant co-therapy may be useful in reducing hunger during intermittent fasting, and show that bitter compounds may regulate appetite independently of meal timing.

Background: Affective responses experienced during exercise are a significant determinant on exercise adherence. We have previously demonstrated that consumption of New Zealand (NZ) blackcurrants preserves cognition by attenuating the feeling of fatigue. This positive affective response correlated with the ability of blackcurrant polyphenols to support monoamine neurotransmission via inhibition of monoamine oxidase-B (MAO-B) activity. Here we explore how the consumption of a NZ blackcurrant juice (BJ) influenced affective responses and potential ergogenic action on the motivation to adhere to a low impact walking exercise., Methods: In a parallel randomized controlled study (Trial registration #: ACTRN12617000319370p, registered 28th February 2017, http://www.anzctr.org.au/ ), 40 healthy sedentary male and female participants drank a BJ or matched placebo (PLA) (n = 20 per group), 1 h prior to a self-motivated treadmill walk, where heart rate and affective responses (exertion [ES] or feeling / mood [FS]) scores) were recorded at 3 or 5 min intervals. Blood glucose, lactate, malondialdehyde (MDA) and platelet MAO-B activity were measured pre- and post-exercise and comparisons were conducted using with Student's t-tests. Subjective data were analysed using 2-way ANOVA with appropriate post hoc tests., Results: Consuming a BJ 1 h prior to exercise caused a 90% decline in platelet MAO-B activity. The exercise had no significant (p > 0.05) effect on blood lactate, glucose or plasma MDA levels. Assessment of affective responses over the first 60 mins (adjusting for participant drop-out) revealed a time-dependent ES increase in both groups, with ES reported by participants in the BJ group consistently lower than those in the PLA group (p < 0.05). FS declined in PLA and BJ groups over 60 mins, but an inverse relationship with ES was only observed within the PLA group (r 2  = 0.99, p = 0.001). Whilst the average time walked by participants in the BJ group was 11 mins longer than the PLA group (p = 0.3), and 30% of the BJ group achieving > 10 km compared to only 10% for the PLA group (p = 0.28), statistical significance was not achieved., Conclusion: Our findings demonstrate that drinking a polyphenolic-rich NZ blackcurrant juice 1 h prior to exercise supports positive affective responses during a self-motivated exercise.