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Item Metabolism of Caprine Milk Carbohydrates by Probiotic Bacteria and Caco-2:HT29⁻MTX Epithelial Co-Cultures and Their Impact on Intestinal Barrier Integrity(MDPI (Basel, Switzerland), 2018-07-23) Barnett AM; Roy NC; Cookson AL; McNabb WCThe development and maturation of the neonatal intestine is generally influenced by diet and commensal bacteria, the composition of which, in turn, can be influenced by the diet. Colonisation of the neonatal intestine by probiotic Lactobacillus strains can strengthen, preserve, and improve barrier integrity, and adherence of probiotics to the intestinal epithelium can be influenced by the available carbon sources. The goal of the present study was to examine the role of probiotic lactobacilli strains alone or together with a carbohydrate fraction (CF) from caprine milk on barrier integrity of a co-culture model of the small intestinal epithelium. Barrier integrity (as measured by trans epithelial electrical resistance (TEER)), was enhanced by three bacteria/CF combinations (Lactobacillus rhamnosus HN001, L. plantarum 299v, and L. casei Shirota) to a greater extent than CF or bacteria alone. Levels of occludin mRNA were increased for all treatments compared to untreated co-cultures, and L. plantarum 299v in combination with CF had increased mRNA levels of MUC4, MUC2 and MUC5AC mucins and MUC4 protein abundance. These results indicate that three out of the four probiotic bacteria tested, in combination with CF, were able to elicit a greater increase in barrier integrity of a co-culture model of the small intestinal epithelium compared to that for either component alone. This study provides additional insight into the individual or combined roles of microbe⁻diet interactions in the small intestine and their beneficial contribution to the intestinal barrier.Item The effect of a 2 week ketogenic diet, versus a carbohydrate-based diet, on cognitive performance, mood and subjective sleepiness during 36 h of extended wakefulness in military personnel: An exploratory study(John Wiley & Sons Ltd on behalf of European Sleep Research Society, 2023-08) Henderson LR; van den Berg M; Shaw DExtended wakefulness, or sleep deprivation, impairs cognitive performance and brain glucose metabolism. A ketogenic diet (KD) provides an alternative fuel source, ketone bodies, that could elicit a metabolic benefit during sleep deprivation. A randomised, cross-over trial was conducted with seven male military personnel. Participants ingested an iso-energetic ketogenic diet or carbohydrate-based diet for 14 days, immediately followed by 36 h of extended wakefulness and separated by a 12 day washout. Cognitive performance, mood, subjective sleepiness, capillary blood glucose, and D-β-hydroxybutyrate concentrations were measured every 2 h during extended wakefulness. Linear mixed models were used to analyse data. D-β-hydroxybutyrate was higher (p < 0.001) and glucose was lower (p < 0.01) on the KD compared with the carbohydrate-based diet. The KD improved psychomotor vigilance task performance (number of lapses, mean reciprocal response time, mean fastest 10% response time (RT), and mean slowest 10% RT; all p < 0.05), running memory continuous performance test performance (RT and number of correct responses per minute; both p < 0.01), and vigour, fatigue, and sleepiness (all, p ≤ 0.001) compared with the carbohydrate-based diet. In conclusion, a KD demonstrated beneficial effects on cognitive performance, mood, and sleepiness during 36 h of extended wakefulness compared with a carbohydrate-based diet.Item Carbohydrate-based oil-in-water emulsions for delivery of short-chain fatty acids : Doctor of Philosophy in Food Technology at Riddet Institute, Massey University, Palmerston North, New Zealand(Massey University, 2021) Le, Hoang DuShort-chain fatty acids (SCFAs) are important functional metabolites. There is clinical evidence to show that they are useful in the prevention of the metabolic syndrome, bowel disorders and certain types of cancer. Therefore, supplementation of SCFAs to the daily diet brings benefits to human health. However, SCFAs are small and water-soluble molecules that are quickly absorbed in the upper gastrointestinal tract. This project aimed to develop carbohydrate-based systems to deliver tripropionin (TP, glycerol tripropionate) and tributyrin (TB, glycerol tributyrate) as sources of propionic and butyric acids into the colon. Two types of emulsion systems were employed, i.e. surfactant-stabilised oil-in-water (O/W) emulsions (single and double-layer systems) and particle-stabilised O/W emulsions (Pickering emulsions). The systems were characterised in terms of structural stability, surface charge, rheological properties, lipolysis degree and release of SCFAs under a static in vitro gastrointestinal digestion and an in vivo study with ileal-cannulated pigs. In the screening experiments, several potential carbohydrate materials were explored, i.e. three modified starches (GUM, N46 and N-LOK), four pectins (PEC) and hydrophobically modified inulin (M-IN), to produce single-layer O/W emulsions. A double-layer O/W emulsion was also produced by combining whey protein isolate (WPI) and chitosan (CS) as the first and second layers, respectively. The capacity of emulsion systems for colon-targeted delivery of SCFAs was then tested using a static in vitro gastrointestinal digestion. The results show that PEC displayed the poorest emulsifying capacity amongst all investigated carbohydrates, leading to an emulsion droplets size (d32) of around 7.3 µm. However, PEC-based formulation was the best system for protection against gastric and intestinal conditions. On the other hand, other single-layer systems and the double-layer system proved to be unstable in the intestinal phase with a significant SCFA release. Deeper investigation on the emulsifying capacity showed that PEC stabilised the O/W emulsion mainly through steric effects. In addition, PEC had the ability to form thick layer around the O/W interface, which was evidenced by confocal laser scanning microscopy and the quantification of adsorbed PEC on the interface. In addition to the above systems, a Pickering O/W emulsion stabilised by hydrophobically modified cellulose nanocrystals (CNCs) was also investigated. The hydrophobic modification of CNCs was carried out, resulting in an increase in static water contact angle from 56o (untreated CNCs) to 80.2o (MCNCs). As a result, the emulsifying capacity of MCNCs was significantly improved. The emulsions prepared from MCNCs ≥ 0.20 wt% were stable against droplet coalescence for up to 4-week storage. In addition, the Pickering emulsions were prone to droplet flocculation at ionic strength ≥ 20 mM NaCl (pH 7.0) or pH < 4.0 (without addition of NaCl), which was due to the charge screening associated with the cellulose molecules at the surface. Similar droplet flocculation was also observed under in vitro gastric conditions, where the emulsions were exposed to low pH and high ionic strength. This gastric-induced structural changes improved physical strength of the emulsions and that enhanced resistance to bile-salt displacement and consequently delayed lipid digestion in the intestinal conditions. In addition, high desorption energy of the MCNC particles at O/W interface of the Pickering emulsion contributed to low lipolysis degree (30–35%). High proportions of SCFAs remaining after the intestinal digestion observed in both PEC and MCNC-based emulsions show a strong promise their use in the colon-targeted delivery of SCFAs. However, CNCs are currently not considered as food-grade materials; therefore, PEC was chosen for the in vivo study using female ileal-cannulated pigs. The in vivo study demonstrated significant higher intestinal lipolysis (~ 51–53%) and lower SCFA release (~ 15%) as compared to the in vitro digestion (~ 40 and 35% respectively). The main reason for the difference between the two models was the absorption of the SCFAs in the pig’s small intestine. However, high proportions of unhydrolysed triglycerides (~ 47–49%) and presence of oil droplets in the ileal-digesta demonstrated successful delivery of SCFAs. Based on the findings in this research, we propose the use of PEC-based emulsion for human trials by incorporating the system into a daily diet or dessert liquid/gel products, such as drinking milk or yogurt. We also believe that the application of MCNC-based Pickering emulsions for colon-target delivery of could be of interest if the regulatory status could be confirmed. The study identifies promising directions for researchers who are interested in improving gut health through delivery of SCFAs to the colon.Item Yield and quality of asparagus (Asparagus officinalis L.) as affected by carbohydrate distribution in relation to daylength, fructan levels, and bud number : a thesis presented in partial fulfillment of the requirements for the degree of Master of Applied Science in Plant Science at Massey University, New Zealand(Massey University, 1999) KarnoThree different aspects of carbohydrate reserves in asparagus were evaluated in this thesis. The first aspect was the effect of daylength on dry matter partitioning between fern and storage roots (Chapter Two), the second aspect was remobilization of soluble carbohydrates (fructans) from different roots during spear harvest (Chapter Three), and the last aspect was the effect of cutting height at harvest on spear yield and quality and stimulation of additional spears using hormone treatment (Chapter Four). The experiments using controlled climate growth chambers were conducted to evaluate the effect of daylength on dry matter partitioning in asparagus plants. The treatments were long constant daylength (15.5 h) and reducing daylength. The results showed that partitioning carbohydrates between fern and crown was influenced by daylength. Plants exposed to reducing daylength showed reductions in plant height, shoot number, number of lateral per shoot, length of lateral, and fern dry weight. This reduction in fern growth was followed by decreasing NAR (net assimilation rate) except at daylengths around 14 hours. However under reducing daylength relatively more carbohydrate partitioned to crown than to fern, as indicated by root:shoot dry weight ratio and allometric ratio between crown and fern. The results also suggested that daylengths around 13.5 to 14 hours seem to be particularly favorable for storing carbohydrates in the roots. In addition, cultivar differences exist in the response to daylength. 'Jersey Giant' was more responsive to daylength than 'UC157' and 'Italian Hybrid' showed a little or no response to daylength. Radioactive labeling using ,¹⁴CO₂ was used to study fructan remobilization from different roots during spear harvest and fructans separation was done using HPLC System. The results showed that spear growth utilized carbohydrate, not only from the nearest roots, but also from more distant new roots. Spears also utilized carbohydrates from distant old roots during harvest but not to the some extent as from new roots. The HPLC system used in this work was able to separate fructans up to a degree of polymerization of 10 (DP10) and produced a single large peak of long chain fructans. The source of carbohydrates used to support spear growth was mainly from long chain fructans (DP more than 10) as long chain frutans decreased sharply during spear growth while short chain fructans (DP3 to DP 10) only decreased slightly. Changes in individual fructans suggested that hydrolysis rates of DP4 and DP3 seem to be a limiting process during fructan hydrolysis. Finally, utilization of carbohydrate reserves and buds to produce marketable spears was studied by the application of cutting height at harvest. The results showed that marketable yield (both first class and total marketable yields) showed an optimum cutting height. The marketable yield increased with increasing cutting height and reached a maximum marketable yield at certain height then decreased with increasing cutting height. The optimum cutting heights for first class marketable yield (quality 1 spears) was lower than those for total marketable yield and varied with cultivars so that variation in cutting height during spear harvest should be used for cultivar evaluation. In addition the application of hormone mixture (BA and GA₃), when spear production had nearly ceased, induced additional spear production indicating that spear production was not limited by bud number but probably by carbohydrate level in storage roots, under the conditions of these experiments. However, considerable variation existed between individual plants.Item The reaction of carbohydrates with ammonia : a thesis presented in partial fulfilment of the degree of Master of Science in chemistry at Massey University(Massey University, 1969) Giltrap, David JohnA feature of typical carbohydrate/ammonia reactions is the formation of complex mixtures of Unidazoles (among other products). These imidazole mixtures have proven difficult to separate in many cases. A theory for cation exchange chromatography of bases has been developed in this work and applied to the separation of imidazole mixtures. The technique used appears to be capable of separating mixtures of imidazoles more effectively than other previously used. D-Glucosone (D-arabo-hexosulose) was papered by the action of benzaldehyde on giucosazone (d-arabo-hexosephenylosazone; and its reaction with ammonia investigated. It was found that the reaction mixture included a number of imidazoles. These imidazoles were separated by the ion exchange technique developed earlier and a total of sixteen compounds giving a positive reaction with the imidazole-specific. Pauly reagent (diazotisod sulphanilic acid) were detected. Fifteen of these compounds were isolated and six were identified by mass spectrometry and/or nuclear magnetic resovance spectrometry. It was also intended to investigate the reaction of 4-O-methyl-D-glucose and ammonia. It was proposed to prepare this compound by methyletion of methyl-2,3,4-tri-O-acetyl- -D-glucopyranoside with methyl iodide in the presence of silver oxide. Under these conditions an acetyl migration from the 4-0 to 6-0 position occurs with the methylation to give methyl-2,3,6-tri-O-acetyl-4-O-methyl- -D-glucopyranoside which may be hydrolysed to give 4-O-methyl-D-glucose. It was intended to prepare the starting material for this reaction (methyl-2,3,4-tri-O-ecetyl- -D-glucopyranoside) from D-glucose by the following steps. (1) hethanolysis of D-gluoose catalysed by an H* cation exchange resin to give methyl- -D-glucopyrunoside. (2) Blocking of the 6-0 position with triphenylchloromethane. (3) Acetylation with acetic anbydride to give methyl-6-O-triphenytaethyl-2,3,4-tri-O-acetyl- -D-glucopyranoside. (4) Removal of the triphenylmethyl blocking group to give the required methyl-2,3,4-tri-O-acetyl- D-glucopyranoside. In fact at the time of this writing the first three steps had been accomplished but attempts to remove the triphenylmethyl blocking group while leaving the ocetyl groups intact had proved unsuccessful.Item Seasonal changes of non-structural carbohydrates related to the growth and development of gentians : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Plant Science at Massey University, Palmerston North, New Zealand(Massey University, 2014) Wang, YuguoThe growth and development of perennial gentians (Gentiana L.) for cut flowers are seasonally controlled. It was hypothesized that in these plants the availability of carbohydrates is a limiting factor influencing the development of crown buds, winter survival, spring re-growth, and their development to flowering; this in turn influences the yield and quality of flowering shoots. By focussing on the seasonal changes of non-structural carbohydrates (NSCs) in various organs, and the effect of differential carbohydrate supply on their growth and development, the current thesis aimed to understand the physiological function of NSCs and their potential influence on the commercial production of flowering shoots. In addition to sucrose, fructose and glucose, the unique carbohydrates, gentianose, gentiobiose and L-bornesitol were found in the gentian hybrids investigated. Gentianose was the main storage carbohydrate, accounting for 50% - 70% total NSCs in storage roots year round, likely playing similar roles as starch and/or fructan do in other plant species. The concentration of these NSCs in various organs fluctuated with seasonal changes, reflecting periods of storage and utilization of NSCs, i.e. the transition between sink and source, in the growth and development of plants during an annual growth cycle. When harvesting flowering shoots, commercial growers of gentian leave a set number of leaves to maintain carbohydrate levels; however, optimization of leaf number/area has never been assessed in terms of carbohydrate reserves. Utilizing varying levels of defoliation, a positive correlation was determined between the resulting concentration of NSCs in crowns (crown buds, rhizomes and storage roots) and both the number and size of new crown buds, supporting the hypothesis that the availability of carbohydrates is a limiting factor influencing the development of crown buds. Experiments in vitro both verified and extended the level of understanding, indicating that the morphogenesis of crown buds, including form, dormancy, and differentiation, was influenced by multiple factors including, carbohydrates, photoperiod and ethylene. Reserves of NSCs in crowns in autumn were positively correlated with both winter survival and spring re-growth. Consistent with these results, the dynamics of NSC concentration and the activity of relevant glycoside hydrolases (GHs) indicated that a large amount of gentianose, up to 106 mg g-1 fresh weight (FW) accumulated in storage roots before winter was subsequently hydrolysed and remobilized to the crown buds to impart cold tolerance in winter and be used during their subsequent re-growth in spring. Substantial gentiobiose, up to 38 mg g-1 FW, accumulated in stem tissue of the shoots before anthesis commenced, while gentianose increased by up to 26 mg g-1 FW in petals before floret opening. These two forms of carbohydrates were considered likely candidates facilitating the fast development of florets. During the development and senescence of florets, the activity of relevant GHs controlling the hydrolysis of gentianose, gentiobiose, and sucrose, was associated with increase of pressure potential driving the opening of floret buds. The stage-specific and dramatic changes of accumulation, conversion and mobilization of NSCs in association with the activity of relevant enzymes, also provided a useful experimental model system to study the metabolism and physiological function of these unique NSCs in gentians. The current study has provided increased understanding of the roles of specific NSCs, particularly gentianose and gentiobiose, in the growth and development of gentians. The thesis also offers a framework of information to improve the balance between carbohydrate storage in underground crowns and harvest of flowering shoots, and therefore benefits the sustainability of yield and quality of flowering shoots in commercial production.Item Effect of carbohydrate ingestion during 'spin' classes on health and fitness parameters, quality of life and mood in recreational exercisers -- Happy Carb Study : a thesis presented for a degree of Masters of Science in Sport and Exercise Science at Massey University, Auckland, New Zealand(Massey University, 2013) Lee, Vivian Ye JeeBackground: Carbohydrate plays an important role in energy provision during exercise, and is a well-known performance-enhancing ergogenic aid. Carbohydrate ingestion has also been shown to influence mood and lead to more pleasurable feelings during exercise. However, carbohydrate ingestion especially from ‘sugary’ sports drinks is perceived to be detrimental for health and weight management. ‘Spin’ classes are popular group fitness cycling sessions where participants work at self-selected exercise intensities. Carbohydrate supplements may allow recreational exercisers to improve exercise performance and enhance the ‘feel-good’ aspects of exercise, leading to an improvement in health and fitness parameters, as well as mood. Extensive research has been conducted with well trained and/or elite athletes to examine the effects of carbohydrate ingestion during single bouts of exercise. However, studies on carbohydrate ingestion during single and repeated bouts of exercise, in recreational exercisers are lacking. Aim: The primary aim of this study was to examine the effect of regular carbohydrate ingestion during exercise in a 10-week intervention on health and fitness parameters, mood and quality of life in recreational exercisers. A secondary aim was to examine the effect of 10-weeks of cycling exercise (spin classes) on health and fitness parameters, as well as quality of life. Methods: Twelve recreational exercisers that attended regular spin classes volunteered to participate in this study. These participants in the Exercise cohort (EXE) were randomly allocated to either Carbohydrate (7.5% carbohydrate solutions; 5 mL/kg of body mass per exercise session; n = 6; CHO) or Placebo (0% carbohydrate, taste- and volume-matched solutions; n = 6; PLA) groups. They each underwent 2 x 45-minute spin classes per week, over a 10-week intervention period. Before each class, participants were given their allocated drinks to consume during the exercise class. Various heart rate parameters, as well as perceptual measures of exertion, pleasure-displeasure and activation (arousal) were assessed after each exercise session. Five non-exercisers were recruited for the Control group (age and gender-matched; CON); they continued their normal daily activities throughout the 10 weeks. All participants (n = 17) were required to attend pre- and postintervention testing sessions where anthropometry, fat composition (BodPod), physiological measures (resting heart rate, resting blood pressure and oxygen saturation rate), cardiorespiratory fitness (cycling test; O2max), quality of life (questionnaire), and various metabolic markers (via collection of blood samples) were assessed. Results: There were no changes from pre- to post-intervention in the measures of body mass, fat composition, waist-to-hip ratio, body mass index (BMI), resting heart rate and systolic blood pressure, oxygen saturation rate, O2max, metabolic markers (triglyceride, total cholesterol, low density lipoprotein and high density lipoprotein) and quality of life measures between CHO and PLA groups (all p > 0.05). However, a significant decrease in the resting diastolic pressure in the CHO group was observed post-intervention (p = 0.02). Throughout the 10-week intervention, mean heart rate, proportion of time spent in different heart rate zones, perceived working resistance, and perceptual ratings of exertion and pleasure-displeasure did not change between CHO or PLA groups (all p > 0.05). However, the level of activation throughout the intervention increased in CHO participants, while it decreased in the PLA group (p = 0.03). Furthermore, a higher proportion of participants within the CHO group were in the ‘high-activation, pleasurable’ quadrant (circumplex model of affect) throughout the intervention. The 2-hour fasted glucose (p < 0.01) and high density lipoprotein (p = 0.04) levels also significantly decreased in the CHO group, while it increased in the PLA group. There were no differences in any health and fitness parameters between EXE and CON groups following the 10-week intervention (all p > 0.05) except for a decrease in waist-to-hip ratio of the EXE cohort, and an increase in the CON group (p = 0.02). Lower BMI (p = 0.03) and resting heart rate (p < 0.01), and higher cardiorespiratory fitness (p < 0.01) and ‘work’ subscale of quality of life (p = 0.03) were seen at baseline in the EXE cohort. Conclusion: Carbohydrate ingestion during regular exercise over a 10-week period did not have any physiological benefits in recreational exercisers. However carbohydrate ingestion appeared to enhance ‘feel-good’ state of recreational exercisers throughout the intervention period. The 10 weeks of regular exercise did not incur any additional benefits relative to no exercise. Nevertheless, the exercisers showed better physiological and cardiovascular fitness relative to non-exercisers. Keywords: Feeling Scale, Felt Arousal Scale, circumplex model.Item The action of ammonia on carbohydrates and related carbonyl compounds : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University of Manawatu, Palmerston North, New Zealand(Massey University, 1965) Grimmett, Murray RossThe chromatography of imidazoles has been studied and a method developed for their quantitative estimation. The following facts have been brought to light:- (i) Formaldehyde does not form imidazoles at room temperature in ammoniacal solution. (ii) From the complex mixture resulting from the interaction of glyoxal with aqueous ammonia imidazole and 2,2'-bis-imidazole have been isolated and identified, while 2-formylimidazole has been tentatively identified. (iii) Glycolaldehyde reacts with aqueous ammonia to form imidazole and 2-hydroxymethylimidazole. (iv) DL-Glyceraldehyde reacts with aqueous ammonia to form a complex mixture of neutral and basic compounds. Dihydroxyacetone, glucose, fructose, mannose, arabinose, lyxose and xylose have been tentatively identified by paper chromatography while ribose was suspected in low concentration. 2-Hydroxymethyl-4(5)-methylimidazole, 4(5)-methylimidazole, 4(5)-(2-hydroxyethyl)imidazole and 4(5)-hydroxymethylimidazole have been isolated and characterised, and their orders and rates of formation studied. (v) Pyruvaldehyde reacts exothermically with concentrated ammonia solution to form four imidazolic compounds. Three of these have been isolated and characterised as 2-acetyl-4(5)-methylimidazole, 2,4(5)-dimethylimidazole and 4(5)-methylimidazole. The latter two compounds were formed in approximately equimolecular proportions. These results fail to confirm Bernhauer's finding that pyruvaldehyde cannot act as a source of formaldehyde in imidazole formation. (vi) Hydroxypyruvaldehyde browns rapidly in aqueous ammonia forming 2-hydroxymethyl-4(5)-methylimidazole, 4(5)-methylimidazole and 4(5)-hydroxymethylimidazole. The yields of the latter two compounds have been found to be higher than from a similar mixture of dihydroxyacetone with ammonia. (vii) Both diacetyl and acetoin react with ammonia to form 2,4,5-trimethylimidazole. (viii) 4(5)-(2-Hydroxyethyl)imidazole has been tentatively identified from the mixture resulting from the interaction of 1,4-dihydroxybutan-2-one with aqueous ammonia. (ix) Arabinose reacts with aqueous ammonia to form a complex mixture of imidazoles from which 4(5)-methylimidazole has been isolated and identified. (x) A chromatographic study has been carried out to determine the orders of formation of imidazoles resulting from the interactions of a number of carbohydrates and their degradation products with aqueous ammonia. Arising from this study have come the following main results:- (a) It appears that, contrary to the findings of Komoto, a number of imidazoles with low Rf values (probably polyhydroxyalkyl-substituted) are formed more rapidly than 4(5)-methylimidazole from hexose sugars with ammonia. (b) Differently linked reducing disaccharides give markedly different patterns of imidazoles under ammoniacal conditions. (xi) As a result of (b) above, a micro-method has been developed for determination of the position of the glycosidic link in reducing hexose disaccharides and homogeneously-linked oligosaccharides.Item The effects of carbohydrate loading 48 hours prior to a simulated squash match : a thesis submitted twards the attainment of Master of Science (MSc) in Exercise and Sport Science, Massey University, Palmerston North, New Zealand(Massey University, 2012) Raman, AaronSquash is a high-intensity, intermittent racket sport that is played by over 15 million people worldwide (Eime & Finch, 2002). Unlike other racquet sports such as tennis, squash has had limited attention in the area of sports nutrition and exercise performance. Furthermore, the effect of carbohydrate ingestion in the days (48 hours) leading up to a squash match has not been explored. Eight squash players who were graded at a Squash New Zealand grade of C1 or above were recruited. Following a familiarisation subjects completed two further trials which consisted of a bout of exhaustive exercise prior to completing a simulated squash match, following a controlled diet for 48 hours in between initial exhaustive exercise bout and match simulation. The match simulation was aimed to mimic the expected metabolic changes during a five-set match lasting about an hour to incorporate the endurance factor of exercise. Performance was measured by the time required to complete each set, which was designed to last ~12 minutes followed by a rest period of ~120 seconds in order to collect measurements. The interventions were assigned in a randomised, single-blind, cross-over design. The interventions consisted of a standardised diet with additional energy intake via the form of a ‘sports drink’. The high-carbohydrate (11.1g·kg-1) diet was primarily delivered in the form of a carbohydrate-containing solution containing maltodextrin; whilst the calorie-matched low-carbohydrate (2.1 g·kg-1) drink was made from a combination of milk powder, protein powder and oil. Oxygen uptake, respiratory exchange ratio (RER), fat and carbohydrate oxidation, and heart rate were continuously collected throughout the trial. Blood glucose and lactate samples were obtained before and after each squash set. Rating of Perceived Exertion (RPE) was also recorded after each set. There was an overall main effect of the intervention as seen from RER (p = 0.016). The difference in RER was further supported by a significant difference seen in fat (p = 0.011) and carbohydrate (p = 0.013) oxidation. Though an interaction of performance time and the intervention was progressing towards significance (p = 0.076), it narrowly missed the α-value of 0.05 to achieve significance. A significant main effect of the trial was not present in both blood glucose and lactate (p > 0.05). However, blood glucose and lactate had a significant effect of time of p = 0.005 and p < 0.001, respectively. These results point towards a beneficial effect of carbohydrate ingestion on squash performance. However, further research will be required to support the findings of this study.Item A 0.8 fructose:maltodextrin ratio enhances endurance performance and exogenous carbohydrate oxidation : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Exercise and Sport Science at Massey University, Wellington, New Zealand(Massey University, 2011) O'Brien, Wendy JeanIntroduction: A ratio of fructose to glucose/maltodextrin of approximately 0.8 in a carbohydrateelectrolyte solution ingested during endurance exercise was recently seen to substantially increase exogenous-carbohydrate oxidation, gut comfort and performance. However, it remains to be determined if the apparent fructose:glucose ratio optima is robust when the possible confounders of differences in solution osmolality and carbohydrate concentration are removed from consideration via clamping, and if the 0.8 ratio also promotes faster fluid absorption. Methods: In a randomised double-blind crossover, 12 male cyclists rode 2 h at 57.5% peak power, then performed 10 repeated-maximal-sprints, while ingesting artificially sweetened water or one of three isomotic 11.25% carbohydrate-salt solutions at 800 mL·h-1, comprising fructose and, maltodextrin/glucose, at the respective mean rates (g·min-1): 1.0, 0.5 (0.5-Ratio); 0.67, 0.83 (0.8- Ratio); 0.83, 0.67 (1.25-Ratio). Each solution was also spiked with 5 g D2O at 30 min into the 2-h preload. 14C-enriched fructose and naturally 13C-enriched maltodextrin/glucose permitted fructose and glucose oxidation rate evaluation by liquid scintillation and mass spectrometry, respectively, and indirect calorimetry. Results: Mean exogenous-fructose and mean exogenous-glucose oxidation rates were 0.27 (SD%, 46), 0.39 (56) and 0.46 g·min-1 (53), and 0.65 (30), 0.71(14) and 0.58 (28) g·min-1 in 0.5-, 0.8- and 1.25-Ratio, respectively; representing oxidation efficiencies (%) for fructose of 56 (12), 60 (7) and 56 (10), for glucose of 67 (16), 86 (11) and 89 (21), and for total exogenous-carbohydrate of 70 (9), 74 (6) and 64 (9), respectively. Relative to 0.5- and 1.25-Ratios, total exogenous-carbohydrate oxidation rate with 0.8-Ratio was very likely 6.4% (90% confidence limits; ±3.1%) and almost certainly 12.7% (±2.6%) higher, respectively, while respective differences in total-exogenous carbohydrate oxidation efficiency was 4.1±1.8% and 8.8 ±1.9%. Endogenous-carbohydrate oxidation with 1.25-Ratio was very likely higher relative to 0.5- and 0.8-Ratio conditions (31.3%; ±26.6% and 37.3%; ±27.8%, respectively) but comparisons of fat and total-carbohydrate oxidation rates were unclear among carbohydrate solutions. Mean sprint power with 0.8-Ratio was moderately higher than 0.5-Ratio (2.9%; 99% confidence limits ±2.8%) and 1.25-Ratio (3.1%; ±2.7%), and almost certainly higher than Water (11.9%; ±3.0%); repeated-sprint fatigue (slope) was possibly attenuated with 0.8-Ratio compared to 0.5- and 1.25-Ratio (2.1%; ±5.7% and 1.7%; ±5.5%, respectively). Blood D2O enrichment differences were possibly small or inconclusive among all solutions. Differences in gastrointestinal comfort during the 2-h ride were trivial/unclear among the carbohydrate conditions, however, increases in abdominal cramping were likely greater with 0.8-Ratio during the performance test. CHO ratio on CHO metabolism and performance Conclusions: Substantial enhancement of endurance performance results from ingestion of 0.8 ratio fructose:maltodextrin/glucose solutions, which is associated with increased exogenous-carbohydrate oxidation efficiency driven largely by a greater contribution from exogenous-fructose oxidation. Further research is required to determine the effect on fluid absorption and the physiological site responsible for the 0.8 ratio effect.