Browsing by Author "Sharim, Nur Syazwana"

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    Deodorisation of protein hydrolysate and extraction of proteins from Hoki (Macruronus novaezelandiae) skin : a thesis presented in partial fulfilment of the requirements for the degree of Master of Food Technology at Massey University, Albany, New Zealand
    (Massey University, 2018) Sharim, Nur Syazwana
    The present study had two main objectives. The first objective was to identify a suitable deodorisation treatment for pre-prepared Hoki skin protein hydrolysate (HSPH) and the second objective was to investigated suitable pre-treatment and extraction processes for collagen and gelatine from Hoki (Macruronus novaezelandiae) skin which resulted in low odour extracts. The off-odour in HSPH post-deodorisation treatments and in the Hoki collagen and gelatine post-extraction processes were assessed by determining the total volatile base nitrogen (TVB-N) and trimethylamine (TMA) concentrations. The sensory technique of flash profiling was employed to determine the odour attributes in all HSPH, gelatine and collagen samples after treatment and extraction processes. In addition to the respective off-odour assessments, the extracted collagen and gelatine were evaluated in terms of total protein content (g protein/100g dry sample), moisture content (w/w%), and yield (w/w% of dry sample). Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) was conducted to determine the molecular weight (kDa) of extracted collagen and gelatine. Amino acid profile analysis was performed to identify the extracted samples. In the first part of this study, dried green tea leaves (GT), powdered tea polyphenol (TP) and dried olive leaves (OL) investigated for deodorisation of HSPH. Using an orthogonal design, three factors (concentration, temperature and time) and three corresponding levels were used in the design. The two most suitable deodorisation treatments for pre-prepared HSPH were 1) deodorant: powdered tea polyphenol; concentration: 0.04 g/ml hydrolysate; temperature: 50˚C; time: 20 min, and 2) deodorant: powdered tea polyphenol; concentration: 0.04 g/ml hydrolysate; temperature: 80˚C; time: 60 min. For a more economical solution, GT was determined to be a possible alternative deodorant to TP by manipulating the total phenolic content prior to deodorisation. For a secondary deodorisation treatment, preliminary results on strong acid hydrogen form ion exchange resin (Dowex G-26) reduced the TMA concentration in partially deodorised HSPH sample significantly (p-value<0.05) from 3.4±0.1 deodorisation to 0.8±0.1 mg of nitrogen/100g wet sample. In the second part of this study, Hoki skins were pre-treated using 0.2 M NaOH solution (1:6 w/v) for 60 min at 18±2oC and then extraction with distilled water (1:10 w/v) for 60 minutes at 50±2˚C. This treatment produced gelatine product with the highest protein content (41.3±0.9 g of protein/100g dry sample) and reduced off-odour based on TMA content (0.9±0.1 mg of nitrogen/ 100 g wet sample). However, a lower gelatine yield recovery of 61.0±1.7 % was determined in this gelatine sample. SDS-PAGE and amino acid profile tests concluded that all pre-treatment and extraction processes successfully extracted gelatine samples as the final product. In contrast, collagen samples were not confirmed as pure collagen in this study. The current findings for both objectives of this study has shown that pre-treating the raw material using acid or alkali prior to subsequent processes is more efficient in reducing the off-odour in the final products rather than employing deodorisation processes as a subsequent countermeasure after hydrolysis and extraction.
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    Fish sauce fermentation technology using New Zealand raw materials : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy (PhD) at at Massey University, New Zealand
    (Massey University, 2025) Sharim, Nur Syazwana
    Despite abundant raw material, industrial fish sauce production is absent in New Zealand, partly due to a paucity of prior research on how well cold-climate South Pacific fish ferment under temperate conditions with local solar salt. The present study investigates the effect of different fish sauce fermentation conditions using New Zealand raw materials (Hoki and snapper heads and frames as well as green-shell mussel), New Zealand solar salts (stoved and unstoved salts) and different temperatures on volatile fatty acid (VFA) production as well as bacterial composition and diversity. Four different fermentation set-ups were conducted to investigate different aims: 1. Laboratory scale fermentation to investigate the influence of different variables (including seafood material, type of salt and temperature) on fermentation. 2. Pilot scale fermentation to investigate the influence of sampling depth on fermentation. 3. Shell-on mussel fermentation to investigate the influence of mussel shell on mussel fermentation 4. Snapper fermentation with mussel shell added to investigate the influence of mussel shell on snapper fermentation. Four VFA were quantified in all fermentation in this study: acetic acid, propionic acid, butanoic acid and 3-methylbutanoic acid. Butanoic acid was detected only in fermentations with unstoved solar salt regardless of seafood material and fermentation temperature. The presence of butanoic acid exclusively in unstoved fermentations may be associated with the presence or abundance of bacterial groups associated with butanoic acid production in these fermentations. The current study found that VFA concentrations generally increased as the fermentation time increased. Salt type had more influence on VFA production than any other single variable including seafood material used, fermentation temperature and sampling depth. It was also revealed that seafood material had more influence on bacterial compositions than any other variable and seafood material appeared to be the primary determinant of the predominant bacterial family groups for the fermentations (Hoki paste – Micrococcaceae and Moraxellaceae; snapper paste – Carnobacteriaceae, Moraxellaceae and Pseudomonadaceae; and mussel paste – Flavobacteriaceae, Moraxellaceae, Paracoccaceae, Pseudomonadaceae and Roseobacteriaceae). Halobacteriales were found only in unstoved salt fermentations suggesting that salt type may be responsible for these results. However, this postulate could not be validated since insufficient intact nucleic acid could be recovered from the salts used to generate adequate bioinformatics information. Shell-on mussel and snapper plus shell fermentation revealed that the presence of mussel shell was associated with high pH in fish sauce fermentation, an observation not previously reported. However, no significant difference in pH was found in fermentations with different shell contents. In pilot scale snapper fermentation, sampling depth did not have a major influence on VFA production. However, sampling depth may influence the growth of some bacterial families to become the predominant groups by the end of the fermentation.