Massey Documents by Type
Permanent URI for this communityhttps://mro.massey.ac.nz/handle/10179/294
Browse
4 results
Search Results
Item Effect of beetroot pomace consumption on acute blood pressure and postprandial blood glucose responses on healthy adults : a thesis presented in the partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics, Massey University, Albany, New Zealand(Massey University, 2023) Gorbani, ElnazBackground: Nitrate-rich beetroot juice (BRJ) supplementation has been shown to improve blood pressure (BP) levels in younger and older adults via increased nitric oxide (NO) production leading to dilation of blood vessels. Similarly, to some extent a reduction of blood glucose (BG) levels through several different mechanisms. However, limited research exists on the by-product of beetroot juice production, beetroot pomace (BRPOM), and its role in controlling BP and BG levels. Objective: To investigate and compare the changes in BP and BG levels in a 3 h period following the ingestion of BRPOM, BRJ and placebo as part of an oral glucose tolerance test (OGTT). Methods: Following an overnight fast, twelve healthy adults consumed either BRPOM (600 mg nitrate, 10 g fibre, 75 g carbohydrate), BRJ (600 mg nitrate, <1 g fibre, 75 g carbohydrate), or placebo (0 mg nitrate, <1 g fibre, 75 g carbohydrate) 15 minutes prior to the OGTT, separated by 1-week washout periods, in a single-blind, crossover design, pilot study. Blood pressure and BG levels were measured at baseline, then every 15 minutes for BG and every hour for BP during a 3 h OGTT. Results: No significant changes in SBP for BRJ (-2.3 ± 5.56 mmHg, p = 0.174), BRPOM (-3 ± 13.4 mmHg, p = 0.456), or PLA (5.2 ± 11.3 mmHg, p = 0.142) treatment group after 3 h. However, there was a trend towards significance in the differences between the three groups (p = 0.075, η²ₚ = 0.404). Clinically meaningful reductions in SBP were observed for BRJ (-2.3 ± 5.56 mmHg) and BRPOM (-3 ± 13.4 mmHg). There were no differences (p = 0.739, η²ₚ = 0.059) in mean glucose incremental area under the curve (iAUC) between BRJ, BRPOM and PLA (232.8 ± 61.9, 242 ± 54.7 and 252.4 ± 60.6 mmol/L/min, respectively). There were no differences between BRJ, BRPOM and PLA in time to peak (p = 0.269, η²ₚ = 0.313), peak glucose levels (p = 0.241, η²ₚ = 0.247), 2 h glucose levels (p = 0.565, η²ₚ = 0.150), 3 h glucose levels (p = 0.395, η²ₚ = 0.233) and percentage increment of postprandial BG (p = 0.783, η²ₚ = 0.048). Conclusion: This pilot study with a small sample size showed a large effect size and clinically meaningful attenuations for acute SBP changes following the consumption of beetroot pomace. Further investigations would be needed to explore the applicability of these findings to hypertensive individuals. However, its impact on acute BG levels remains non-significant, possibly influenced by the small sample size and participants’ baseline normoglycaemic levels. Further research is needed to explore potential effects in a hyperglycaemic population.Item Extraction, composition and some of the physical and chemical properties of dietary fibre : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in the Department of Food Technology, Massey University(Massey University, 1985) Holloway, Warren DesmondThe extraction and some of the chemical and physical properties of components from plant cell walls are described in this thesis. The chemical composition of the extracted polymers and the morphological and physical changes occurring in wheat bran at various stages of an extraction sequence and the metal binding capacities of the extracts were determined. A sequential extraction procedure using water, amylase, oxalate and alkali (before and after delignification) was used to isolate components of plant cell walls. This enabled water soluble and water insoluble fibres from bean, cabbage, lettuce, tomato, peach, pumpkin, kumera, onion, pear, wheat bran, lucerne, clover and ryegrass to be obtained. The water soluble fibres were shown to be composed predominantly of arabinose, galactose and uronic acid, whereas the water insoluble fibres contained mainly arabinose and xylose. The viscosities of the alkali soluble fibres extracted from wheat bran, before and after chlorite delignification, and after solubilisation in N-methyl-morpholine-N-oxide were determined. The arabinoxylan extracted before delignification, yield of 7.9 g/100 g, had a limiting viscosity number of 220.6 ml/g, whereas the arabinoxylan extracted after chlorite delignification, yield of 3.8 g/100 g, had a limiting viscosity number of 74.2 ml/g. when the solvent N-methyl-morpholine-N-oxide had been used to dissolve the nondelignified arabinoxylan, a considerable decrease in viscosity, to 6.3 ml/g, was observed. It was concluded that direct extraction (no delignification) of wheat bran, enables a less degraded arabinoxylan to be extracted in adequate yields. The use of N-methyl-morpholine-N-oxide as a solvent for arabinoxylan resulted in extensive degradation. The structural changes in wheat bran at each stage of the extraction sequence and when dimethylsulphoxide (DMSO) was substituted for alkali were observed using light and scanning electron microscopy. It was shown that the commercially ground sample of wheat bran contained a high proportion of starch, which was removed after the amylase treatment. Alkali removed cell wall material predominantly from the aleurone layer. DMSO was not an efficient extractor of arabinoxylans from cell walls, a yield of only 0.4% being obtained and the aleurone cell walls remaining intact. The arabinoxylan, extracted with DMSO, had a higher ferulic acid and acetyl content than the arabinoxylan extracted with alkali. The interactions of fibres with metal ions (copper, iron, zinc, calcium, potassium, magnesium, manganese and sodium) using concentrations that would be expected in the human small bowel after a 'typical' meal were investigated. It was found that the water soluble fibres bound more copper, iron and zinc than the water insoluble fibres. The copper, iron and zinc binding occurred with a displacement of calcium, magnesium and manganese. The water insoluble fibres (hemicelluloses) contained a higher calcium content than the soluble fibres (pectins). After acid treatment, sodium was bound preferentially rather than calcium to hemicellulose. Possibly divalent calcium ions play a role in stabilising the hemicellulose components of plant cell walls. The binding capacities and mechanisms of zinc binding to wheat bran, its components and to phytate were determined. Zinc binding capacities (µM/g dry weight of plant material) in order of magnitude were; phytate (6582 ± 192), DMSO soluble hemicellulose (5089 ± 921), water soluble fibre (4038 ± 216), cell walls (1012.6 ± 193), lignocellulose (510 ± 41.9), cold water soluble fibre (440.0 ± 15.3), alkali soluble hemicellulose (227.9 ± 61.4), bran (167.7 ± 12.7), bran ex oxalate (148.3 ± 50.0), bran ex ethanol (142.3 ± 4.4) and cellulose (57.4 ± 5.3). The water soluble fibre, fractionated using ammonium sulphate, composed predominantly of arabinose (24.0%), galactose (20.3%), xylose (18.6%), mannose (16.2%), glucose (10.9%) and rhamnose (6.0%), bound zinc more strongly than phytate or the DMSO hemicellulose. The Scatchard plots of zinc binding to phytate and to the fibres, except for the water soluble fibres, were concave and markedly nonlinear, suggesting that the binding mechanism is by negative cooperativity or site heterogeneity. The Scatchard plots of zinc binding to the water soluble fibres showed well pronounced maximum, indicating the binding mechanism is by positive cooperativity. Part I of this thesis describes the studies undertaken to isolate and determine the chemical composition of different types of fibres from bean, cabbage, sweet potato, lettuce, onion, peach, pear, pumpkin, tomato, wheat bran, white clover, lucerne and ryegrass. This study has been published in the Journal of the Science of Food and Agriculture 1983, 34: 1236-1240 (see Appendix F). Part II of this thesis describes studies undertaken to investigate the viscosity of hemicelluloses obtained using the extraction procedure and after solubilisation in N-methyl-morpholine-N-oxide. The work has been published in carbohydrate Research 1985, 143: 271-274 (see Appendix G). Part III describes studies undertaken to observe the morphological structure of wheat bran, changes occurring during the extraction sequence and influence of DMSO when substituted for alkali. Part IV describes studies on binding of metals to water soluble and insoluble fibres from fruits, vegetables, bran and grasses. Part v describes a more detailed study of zinc binding to wheat bran, its fibre components, and to phytate. The thesis concludes with a general discussion of the findings and a summary of the conclusions.Item Utilization of sweet potato starch, flour and fibre in bread and biscuits : physico-chemical and nutritional characteristics : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Technology in Food Technology, Massey University(Massey University, 2008) Mais, AntonSweet-potato contains a limited amount of protein, although rich in dietary fibre content and carbohydrate, so a successful combination with wheat flour for bread and biscuit production would be nutritionally advantageous. In particular, the role of these ingredients in relating to acceptability of breads and biscuit with higher percentage of sweet potato starch, flour in wheat flour. In this study, starch, flour and residue fibre of three sweet-potato varieties (red, orange and white -types) were studied. The 5 -10% combination levels for biscuit-making were found to be acceptable, without affecting the quality of the biscuit (combination of texture and biscuit size). In bread, bread containing 15% red and white replacement starches and orange replacement flour was found to be acceptable level, without affecting the quality of the bread, in an attempt to replace wheat at higher per cent level. The physicochemical study was complemented with a nutritional study to determine beneficial effects of food rich in dietary fibre and starches, in the context of improving diet related problems. RVA results showed sweet-potato ingredients affected differently the pasting temperature, peak viscosity and final viscosity of the normal wheat flour (p<0.05). Fibre inclusion showed large reduction in viscosity and swelling of sweet potato starch. Biscuits and breads containing sweet-potato starch and flour are low in amylose, and digest slowly because of lowly oriented and ‘crystalline’ areas within the granules enable to swell or to ungelatinised starch granules, whereas wheat control biscuit was able to gelatinised starch and exerted a greater effect upon digestibility. There are many other factors that need to be considered when analysing the in vitro starch digestibility such including amylose content, amylopectin structure and presence of fibre and gelatinising. Sweet-potato starch, flour and fibre addition show least effect on bread texture and size and starch, flour and fibre replacement. However, in in vitro starch digestibility test higher values RSS was recorded for starch addition followed by flour addition.Item Effects of dietary fibre and tea catechin, ingredients of the Japanese diet, on quol production and bone mineral density in isoflavone-treated ovariectomised mice(Cambridge University Press, 2012) Tousen Y; Uehara M; Kruger MC; Ishimi YEquol is a metabolite of the isoflavone daidzein (Dz) and is produced by the bacterial microflora in the distal intestine and colon. Some epidemiological studies have reported an association between increased equol production and intakes of green tea or dietary fibre, which are ingredients of the standard Japanese diet. We examined the effects of a diet supplemented with Dz and tea catechin or dietary fibre on equol production and bone mineral density in ovariectomised (OVX) mice. Female mice of the ddY strain were either sham operated or OVX. OVX mice were fed a control diet, a 0·1 % Dz-supplemented diet or a 0·1 % Dz diet supplemented with one of the food components commonly consumed in the Japanese diet. The mice were given 1 % tea catechin (w/w) as part of the diet in Expt 1 or 5 % polydextrose (PD) and 5 % raffinose (Raf) (w/w) as part of the diet in Expt 2. Catechin reduced serum equol levels and attenuated the beneficial effect of Dz on femoral bone loss. The soluble dietary fibres PD and Raf stimulated equol production, and enhanced the bone-protective effects of Dz on femoral bone. These results suggest that dietary fibre, in particular, PD, may alter the bioavailability of isoflavones and prevent osteopenia in OVX mice.