Development of bread products containing Chordaria cladosiphon (mozuku) and its bioactive extract fucoidan : a thesis presented in partial fulfilment of the requirements for the degree of Master of Food Technology at Massey University, Albany, New Zealand

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Many seaweeds such as Chordaria cladosiphon, commonly known as mozuku, have been shown to contain several health promoting components such as dietary fibres, antioxidants, and a range of bioactive compounds. Mozuku is an edible brown seaweed which constitutes an important part of the diet of native Okinawans who enjoy long lives and consume the seaweed mixed with various seafoods and vegetables. Brown seaweeds and their isolated compounds, specifically a long-chain polysaccharide known as fucoidan, are reported to retard the formation and growth of various cancer cells in humans as well as having anticoagulation, antiviral and immunological activities. The present study developed wheat and gluten-free bread formulations containing mozuku powder in order to introduce its potential health effects into a staple food product thus making it more accessible to a wider range of consumers. Nutritional analysis of mozuku powder was determined by proximate analysis, fatty acid analysis and amino acid analysis, particle size distribution of the powder was also determined. Mozuku powder was added to modified wheat bread and developed gluten-free bread formulations with adjustments in levels of added salt. The effects of mozuku powder inclusion on bread quality were assessed by measuring changes in bread quality parameters, with standard methods being used to determine texture characteristics, crust and crumb colour, specific volume and water activity. Samples of gluten-free and wheat bread were evaluated by consumer sensory panellists for appearance, texture, aroma, taste, and overall acceptability using the 9-point hedonic scale. Microbial stability of wheat bread was determined by enumeration of total aerobic plate counts and, yeast and mould counts over the course of 3 days. Particle size distribution of mozuku powder showed that 90% of particle by weight were less than 500μm in diameter and that only 10% were less than 90μm. At these particle sizes, mozuku flakes were observable in the finished loaves. Nutritional analysis of mozuku powder contained (w/w, wet basis) 46.9% ash, 30.4% dietary fibre, 19.0% sodium, 5.4% protein, 4.7% available carbohydrates, 1.0% fat, 0.13% sugar and an overall energy content of 209.1 kJ/100 g. The most prevalent amino acids in mozuku powder were aspartate (0.59 mg/100 mg), glutamate (0.55 mg/100 mg), and leucine (0.42 mg/100 mg). Of the fatty acids, palmitic (69%) and oleic acid (13%) were present in highest concentrations however due to the total fat content of 1% they are unlikely to contribute to overall health. Addition of mozuku powder to both gluten-free and wheat bread formulations with adjusted salt levels, reduced specific volume and breadcrumb lightness of the products without affecting water activity. However, inclusion of the seaweed powder in formulations increased redness/yellowness in the bread crumb. There were no significant differences (P<0.05) in textural changes between wheat bread containing 1 and 2 % mozuku powder. However, wheat bread containing 2 % mozuku powder was characterised by decreased cohesiveness with no perceived changes in hardness, chewiness, resilience and springiness. Wheat bread containing 1% and 2% mozuku powder were well accepted by consumer sensory panellists receiving mean scores of 6.8 and 6.4 in overall acceptability on the 9-point hedonic scale. The addition of mozuku powder to wheat bread at 1% and 2% did not affect the microbial stability of the loaves during storage at 20°C for 3 days. With respect to gluten-free bread formulations, mozuku powder (up to 3%) did not affect texture (P<0.05), however, the inclusion of 4% mozuku powder in gluten-free bread increased hardness, chewiness and resilience. The gluten-free formulation containing a concentration of 2.5% mozuku powder was selected for consumer sensory trials due to its favourable quality results and received a mean score of 6.4 in overall acceptability on the 9-point hedonic scale thus indicating the product was well-liked by consumer sensory panellists. In this study, wheat bread and gluten-free bread containing variable levels of mozuku powder were successfully developed. Wheat bread containing 1% and 2% mozuku powder and gluten-free bread containing 2.5% mozuku powder had desirable textural characteristics, were well liked by consumer sensory panellists, and would be suitable for use in clinical trials.
The following images have been removed for copyright reasons: Table 2.2 (MacArtain et al., 2007, p. 539 Table 7); Table 2.3 (MacArtain et al., 2007, p. 536 Table 2); Figure 2.2 (Thanh et al., 2013, p. 2439 Figure 8); Figure 2.3 (Ale et al., 2011, p. 2115 Figure 2); Figure 2.4 (Lamacchia et al., 2014, p. 579 Figure 3). Other possibly copyrighted images remain owing to broken links or for clarity's sake.
Bread, Marine algae as food, Chordaria cladosiphon, Mozuku, Fucoidan