Nazimah Hamid

Fucoxanthin content and antioxidant properties of Undaria pinnatifida.

This study investigated the fucoxanthin content of New Zealand (NZ) Undaria pinnatifida harvested from two locations in the Marlborough Sounds, New Zealand across its growing season. Fucoxanthin content and antioxidant properties of processed New Zealand U. pinnatifida and commercial wakame from Japan and Korea were further compared. Results showed that U. pinnatifida harvested from Port Underwood had higher fucoxanthin content in the blade compared to Pelorus Sound. The sporophyll also contained a significant amount of fucoxanthin throughout the harvest season, although lower than in the blade. Two antioxidant measurement methods, DPPH and CUPRAC, were utilised to measure antioxidant activities. Processed NZ U. pinnatifida had a lower fucoxanthin content and antioxidant activity than freeze-dried Undaria. Fucoxanthin content and antioxidant activities of NZ processed U. pinnatifida were not significantly different from other commercial samples from Japan and Korea. In conclusion, U. pinnatifida in New Zealand has a great potential to be a food and nutraceutical resource.

Fucoidan from New Zealand Undaria pinnatifida: monthly variations and determination of antioxidant activities.

The content and composition of fucoidans extracted from Undaria pinnatifida from mussel farms at the Marlborough Sounds, New Zealand were investigated using CaCl2 extraction. Crude fucoidan (F0) was subsequently extracted on a monthly basis from U. pinnatifida harvested from July to October 2011 from mussel farms in the Marlborough Sounds, New Zealand. Fucoidan yield varied between the frond and sporophyll parts of the algae, with the sporophyll consistently the highest content. The yield from the sporophyll increased significantly from July (25.4-26.3%) to September (57.3-69.9%). Sulphate content in the extracted fucoidan increased more than twice within the same period, while fucose content remained constant. F0 was further purified by ion-exchange chromatography to yield three fractions, F1, F2 and F3. All three fucoidan fractions contained fucose as the primary sugar component followed by galactose, with xylose, glucose and mannose as minor constituents. All fractions exhibited strong antioxidant activities using the DPPH scavenging and CUPRAC assays. This study showed that sporophyll maturation of U. pinnatifida in New Zealand influenced fucoidan content and composition. Sporophyll fucoidan could potentially be a good resource for natural antioxidants.

Seasonal changes in lipid, fatty acid, α-tocopherol and phytosterol contents of seaweed, Undaria pinnatifida, in the Marlborough Sounds, New Zealand

Monthly changes of lipids, fatty acids, phytosterol and α-tocopherol in New Zealand brown macroalgae, Undaria pinnatifida, were investigated. U. pinnatifida lipid content ranged from 17 to 45mg/g in the blade and between 21 and 63mg/g in the sporophyll. It was a rich source of polyunsaturated fatty acids (PUFAs) with n-6 PUFAs reaching a maximum in December. The unsaponifiable lipid was comprised of α-tocopherol, fucosterol and 24-methylenecholesterol, that were found in higher concentrations in the winter. The content of fucosterol ranged from 146 to 338μg/g, and that of 24-methylenecholesterol between 8.4 and 48μg/g. The contents of α-tocopherol were 13, 14 and 9.6μg/g in winter, spring and summer, respectively. New Zealand U. pinnatifida sporophyll had a high level of beneficial lipids and could potentially be further processed as a source of functional food lipids instead of being discarded as a waste product.

Evaluation of pre-rigor injection of beef with proteases on cooked meat volatile profile after 1 day and 21 days post-mortem storage.

This research was carried out to determine the effects of pre-rigor injection of beef semimembranosus muscle with nine proteases from plant and microbial sources, on the volatile profile of cooked beef after 1 day and 21 days post-mortem (PM) storage using Solid-phase microextraction gas chromatography mass spectrometry analysis. A total of 23 aldehydes, 5 ketones, 3 furans, 8 nitrogen and sulphur compounds, 4 alkanes, 7 alcohols and 6 terpenes were detected. Eleven volatile compounds characteristic of ginger flavour were detected in zingibain-treated meat. Benzaldehyde significantly increased (p<0.05) only in kiwifruit juice (KJ), fungal 31 protease and Asparagus protease (ASP) treated samples from 1 day to 21 days PM storage. A significant increase (p<0.05) in 3-methylbutanal was observed in KJ, bacterial and fungal protease treated samples at 21 days PM storage. Treatments with bromelain, papain, ASP, actinidin, and KJ (except KJ 21 days) proteases resulted in flavour profiles closer to that of the control beef sample.

Anti-Proliferation Potential and Content of Fucoidan Extracted from Sporophyll of New Zealand Undaria pinnatifida

Undaria pinnatifida is a species of brown seaweed known to contain rich amounts of fucoidan, a sulfated polysaccharide known to possess various biological activities. We isolated crude fucoidan (F0) from the sporophylls of U. pinnatifida grown in the Marlborough Sounds, New Zealand. Sulfate content, uronic acid content, and molecular weight of F0 were 15.02, 1.24, and >150 kDa, respectively. F0 was fractionated to yield three further fractions: F1, F2, and F3. Cytotoxicity of two major fractions was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The algal fucoidans specifically suppressed the proliferation of three cancer cell lines with less cytotoxicity against the normal cells. Selective cytotoxicity could relate to the distinctive structures of each fucoidan fraction. Results from this study provide evidence that fucoidan, especially from U. pinnatifida grown in New Zealand, possesses great potential to be used as a functional food to reduce cancer risk or supplement cancer treatment.

The effect of background music on food pleasantness ratings

This study investigated whether samples of pleasant, neutral and unpleasant music can impact food perception. To this end, the pleasantness of three different types of chocolate gelati (milk chocolate, dark chocolate and bittersweet chocolate) was determined using 50 participants exposed to silence (the reference condition) and three music samples differing in self-rated preference. To measure hedonic responses to the gelati samples, the Time Intensity method was utilized to derive the maximum intensity of pleasantness and the area under the Time Intensity pleasantness curve. The presence of non-preferred music significantly decreased the pleasantness ratings of all three types of chocolate gelati tested, while preferred music increased perceived pleasantness ratings of dark and bittersweet chocolate gelati, but not milk chocolate gelato. Time Intensity parameters for pleasantness ratings did not differ significantly across the three different types of chocolate gelati in the silent condition, suggesting that listening to the music influenced gelati pleasantness ratings. This study demonstrated that the pleasantness of gelati changed with music valence. The findings echo previous studies emphasizing the importance of crossmodal effects between music and food perception.

Effects of meat addition on pasta structure, nutrition and in vitro digestibility.

In our study, semolina flour was substituted with beef emulsion (EM) at three different levels of 15, 30 and 45% (w/w) to develop a pasta with enhanced nutritional profile. The protein, fat, and water content significantly increased with addition of meat. The addition of meat enhanced the pasta gluten network. The redness and yellowness of cooked pasta increased with meat addition. Tensile strength increased from 0.018N/mm(2) in the control sample to 0.046N/mm(2) in 45% beef emulsion (45EM) sample. All meat-containing samples had significantly higher elasticity than control (0.039N/mm(2)). GI significantly decreased and IVPD value increased in 45EM sample. Five essential amino acids (leucine, lysine, methionine, threonine, tryptophan) in pasta digesta increased significantly with increasing meat addition.

Changes in total nitrogen and amino acid composition of New Zealand Undaria pinnatifida with growth, location and plant parts.

Undaria pinnatifida is known as unwanted organism in New Zealand. However, Wakame is a traditional food made of U. pinnatifida, which is now cultured extensively in East Asia. Therefore, it is important to examine this introduced alga as a potential source of dietary protein for human consumption in New Zealand. This study determined total nitrogen content and amino acid profile of New Zealand U. pinnatifida harvested from the Marlborough Sounds on a monthly basis from June to November 2011. Total average nitrogen content and crude protein content was 21.02 mg/g dry weight and 13.1% of dry weight, respectively. The three most abundant amino acids that contributed to flavour (glutamic acid, aspartic acid and alanine) were present and the most abundant essential amino acids were arginine, leucine, lysine and valine. The results showed that the amino acid content in blades from the exposed farm was significantly higher (P < 0.05) than the others. Sporophyll maturation of U. pinnatifida in New Zealand influenced protein content and amino acid composition. Sporophyll, considered as a waste product by many, was found to be a potentially good source of protein.

Effect of Pulsed Electric Fields on the Flavour Profile of Red-Fleshed Sweet Cherries (Prunus avium var. Stella)

The aim of this research was to study the effect of pulsed electric fields (PEF) on the flavour profile of red-fleshed sweet cherries (Prunus avium variety Stella). The cherry samples were treated at a constant pulse frequency of 100 Hz, a constant pulse width of 20 μs, different electric field strengths between 0.3 and 2.5 kV/cm and specific energy ranging from 31 to 55 kJ/kg. Volatile compounds of samples were analysed using an automated headspace solid phase microextraction (HS–SPME) method coupled with gas chromatography-mass spectrometry (GC–MS). A total of 33 volatile compounds were identified with benzaldehyde, hexanal, (E)-2-hexenal, (Z)-2-hexen-1-ol, and benzyl alcohol being the predominant volatiles in different PEF-treated samples. Aldehydes namely butanal, octanal, 2-octenal, and nonanal, and (Z)-2-hexen-1-ol increased significantly 24 h after PEF treatment at electric field strengths of more than 1.0 kV/cm. Samples incubated for 24 h after PEF treatment (S3) generated higher concentrations of volatiles than samples immediately after PEF treatments (S2). Quantitative results revealed that more flavour volatiles were released and associated with S3 samples after 24 h storage and S2 samples immediately after PEF both with the highest electric field intensities. Interestingly, this study found that the PEF treatments at the applied electric field strength and energy did not result in releasing/producing undesirable flavour compounds.

Effect of Antifreeze Peptide Pretreatment on Ice Crystal Size, Drip Loss, Texture, and Volatile Compounds of Frozen Carrots

Ice crystal formation is of primary concern to the frozen food industry. In this study, the effects of antifreeze peptides (AFPs) on ice crystal formation were assessed in carrot during freezing and thawing. Three synthetic analogues based on naturally occurring antifreeze peptides were used in this study. The AFPs exhibited modification of ice crystal morphology, confirming their antifreeze activity in vitro. The ability of the synthetic AFPs to minimize drip loss and preserve color, structure, texture, and volatiles of frozen carrot was evaluated using the techniques of SEM, GC-MS, and texture analysis. The results prove the potential of these AFPs to preserve the above characteristics in frozen carrot samples.