effect of drying temperature on the content of fucoxanthin...

J. Trop. Agric. and Fd. Sc. 45(1)(2017): 25 – 36

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Article history Received: 26.3.15 Accepted: 4.2.16

Authors’ full names: Norra Ismail, Aminah Abdullah, Suri Rowi and Arif Zaidi Jusoh E-mail: [email protected] ©Malaysian Agricultural Research and Development Institute 2017

Effect of drying temperature on the content of fucoxanthin, phenolic and antioxidant activity of Malaysian brown seaweed, Sargassum sp. (Kesan suhu pengeringan terhadap kandungan fukozantin fenolik dan antioksidan pada rumpai laut perang Malaysia Sargassum sp.) I. Norra1, A. Aminah 2, R. Suri1 and J. Arif Zaidi1 1Food Science Technology Research Centre, MARDI Headquarters, Persiaran MARDI-UPM, 43400 Serdang, Selangor, Malaysia 2School of Chemical Science and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

Abstract This study evaluated the influence of different drying temperatures on the content of fucoxanthin, phenolic and antioxidant activity of Malaysian brown seaweed, Sargassum sp. The brown seaweed was dried at 40, 65, and 90 °C. All seaweeds dried powders were assessed for total lipid and fucoxanthin. Non-boiled and boiled water extract were analysed for their total phenolic content (TPC) using Folin-Ciocalteu method and antioxidant activities were assayed by ferric reducing antioxidant power (FRAP) and 2, 2-phenyl-1-picrylhydrazil (DPPH) radical scavenging. Results of the study showed that with increasing of drying temperature, it will enhance significantly (p <0.05) the fucoxanthin content, TPC as well as antioxidant activity of this dried brown seaweed in the boiled extracts. The dried brown seaweed at 90 °C give the highest value for fucoxanthin content, total phenolic content and antioxidant activity. Keywords: seaweed, fucoxanthin, drying, total phenolic content, DPPH, FRAP

Introduction Seaweeds are considered to be a rich source of antioxidants (Cahyana et al. 1992). Antioxidant activity is intensively focused due to the currently growing demand from the pharmaceutical industries where there is interest in antiaging and anticarcinogenic natural bioactive compounds, which possess health benefits (Soo-Jin et al. 2005a). Almost all photosynthesising plants including seaweeds are exposed to a combination of light and high oxygen concentrations, which lead to the formation of free radicals and other strong oxidising agents, but they seldom suffer any serious photodynamic damage during metabolism. This fact implies that their cells have some

protective antioxidative mechanisms and compounds (Matsukawa et al. 1997).

Recently, the potential antioxidant compounds in seaweeds were identified as some pigments (fucoxanthin, astaxanthin, carotenoid) and polyphenols (phenolic acid, flavonoid, tannins). These compounds are widely distributed in seaweeds and are known to exhibit higher antioxidative activities (Soo-Jin et al. 2005a). They are also excellent source of vitamins, dietary fibres, minerals and protein (Lee et al. 2008) and have been classified according to their pigmentation into brown (Phaephyta), red (Rhodophyta) and green (Chlorophyta) seaweeds. Brown seaweed is known to

Effect of drying temperature

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contain more bioactive components than either green or red seaweeds. The pigment fucoxanthin is what gives the brown seaweed their greenish-brown colour. Fucoxanthin and its metabolites have been reported to possess antioxidative, anticancerous, antiobesity and antiinflammatory properties (Juan et al. 2011).

The antioxidant activity of several brown seaweeds species had been investigated such as Padina antilarum (Chew et al. 2008), Petalonia binghamiae (Takashi et al. 2006), Ecklonia cava, Ishige okamurae, Sargassum fullvelum, Sargassum horneri, Sargassum coreanum, Sargassum thunbergii and Scytosipon lomentaria (Soo-Jin et al. 2005b) were reported. Edible brown seaweeds from North Borneo, Malaysia which are Dictyota dichotoma, Sargassum polycystum and Padina sp. (Patricia et al. 2008) were also reported. This indicates that brown seaweed can be a good source of natural antioxidant which potentially to be used as an ingredient in food and beverages product.

In nature, seaweeds contain a large amount of water. In fresh form, approximately about 75 – 85% water and 15 – 25% organic components and minerals. As seaweeds are perishable when fresh, thus it could deteriorate within a few days after harvest. Therefore, drying is an essential step before they can be used in industrial processing. Drying decreases the water activity that retards the microbial growth, helps to conserve the desirable qualities and reduces the storage volume (Gupta et al. 2011). However, enzymatic and/or non-enzymatic activities that may occur during drying of the fresh plant tissues may lead to significant changes in the composition of phytochemicals (Capecka et al. 2005). Hence, drying is an important technique in seaweed processing.

From our previous study, antioxidant capacity seemed to be influenced by the drying method. Among three drying method used (freeze-, sun- and oven-drying), oven-drying at 50 °C is superior drying process for Sargassum sp. and have been chosen as a drying method. Generally, some bioactive compounds will be degraded during drying and extraction at a high temperatures. In order to investigate the point at which the temperature begins to significantly and adversely affect phytochemical content in Sargassum sp., the range of temperature from low (40 °C) to high (90 °C) were chosen in this study. Hence, the aim of this study is to evaluate the effect of different oven drying temperature on the content of fucoxanthin, phenolic and antioxidant activities of edible Malaysian brown seaweeds. Materials and methods Materials Malaysian brown seaweed, Sargassum sp. was obtained from Perusahaan Rumpai Laut Juni Kg. Singgamata, Pulau Bum-Bum, Semporna, Sabah. Fresh brown seaweeds were sun dried to avoid deterioration during transportation to Peninsular Malaysia. Chemicals and reagents The solvents used for high performance liquid chromatography (HPLC) analysis were of HPLC grade. All other solvents and chemicals used in the study were of analytical grade. Standard fucoxanthin was purchased from Sigma-Aldrich (≥95% purity established by HPLC) Sample preparation The sun dried brown seaweed was soaked for 24 h in order to remove all the epyphites including salt and sand that attached to the surface. The sample was washed thoroughly with tap water, drained and followed by drying.

I. Norra, A. Aminah, R. Suri and J. Arif Zaidi

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Drying procedure The frozen seaweeds were thawed before being cut manually with scissors into a uniform size (1 cm x 1 cm), so that size difference would not affect drying time. Approximately 100 g of seaweed was weighed and placed on a flat tray and dried in a hot air oven at different temperatures of 40, 65 and 90 °C. The dried samples were then grinded by using Ultra Centrifugal Mill (Retch ZM200) with particle sizes 0.25 mm at 8000 rpm to get the powder. The dry solids content for each temperature was determined by using moisture analyser (HB43 Halogen Moisture Analyser, Mettler Toledo). Total lipid contents Total lipid (TL) contents were determined according to the method of Dedi et al. (2011). The TL in the dried seaweed for each drying temperature were extracted overnight with methanol (1:10 w/v) and shaken during the extraction time to ensure complete extraction. The extracts were filtered using filter paper (Whatman No.4 paper). The residue was re-extracted by repeating the above steps under the same conditions until the extraction solvents became colourless. The filtrates were pooled, placed in the rotary evaporator and the methanol was evaporated from the supernatants at 50 mm Hg pressure and 30 °C. TL in the form of viscous green residue was weighed, re-dissolved in methanol and stored at -20 °C until further analysis. TL was used for further analysis of fucoxanthin content. All the extractions were carried out under dim light. Fucoxanthin analysis by HPLC The methods of Maeda et al. (2005) and Dedi et al. (2011) were adopted for fucoxanthin content determination by reversed-phase HPLC (RP-HPLC). All RP-HPLC experiments were carried out using Waters 2695 HPLC system equipped with

photo diode-array spectrophotometric detector (Waters 2996) at 28 °C using Genesis C18 column (4 µm particle size, 0.46 cm internal diameter x 25 cm in length.). The mobile phase was methanol-acetonitrile (70:30, v/v). The flow rate was 1.0 ml/min. the detector was set at 450 for detecting fucoxanthin (Dedi et al. 2011; Yan et al. 1999; Maeda et al. 2005). Briefly, an aliquot of TL was dissolved in the mobile phase, filtered with a 0.2 µm membrane filter, and an aliquot of the filtered sample was submitted to HPLC analysis. The amount of fucoxanthin content in seaweed samples was quantified from the peak area using a standard curve prepared from standard fucoxanthin (y = 73.342x – 0.075, R2 = 0.9996) and were expressed as mg/g dry weight. All measurement was done in triplicate for each extract. Determination of total phenolic content All dried powders were extracted with non-boiled distilled water (40 °C) for 3 h using temperature controlled shaking water bath with continuous shaking to ensure complete extraction and boiled distilled water for 10 min (double boiled technique). The extracts were filtered and the filtrates were subjected to the TPC and AOA assays. The TPC in the extract was determined using Folin-Ciocalteau reagent (Singleton and Rossi 1965) with some modifications. Fresh weight of each sample were converted into dry weights on the basis of the moisture content. Each of the aqueous extract (100 µl) was transferred into a test tube and then mixed thoroughly with 0.5 ml Folin- Ciocalteau reagent (prediluted 10-fold with distilled water). After mixing for 5 min, 1.0 ml of 7.5% (w/v) sodium carbonate was added. The mixtures were agitated with a vortex mixer, and then allowed to stand in the dark for 120 min at ambient temperature. The absorbance of the non-boiled and boiled water extracts and a prepared blank were


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measured at 765 nm using a spectrophotometer (UV-vis model 50 Probe). The TPC was expressed as mg gallic acid equivalent (GAE)/g dry weight which was determined from known concentrations of gallic acid standard prepared similarly. Data were reported as a mean ± standard deviation for three replications. Ferric reducing antioxidant power (FRAP) The ferric reducing power of the SDP extracts was determined by using potassium ferricyanide–ferric chloride method (Oyaizu 1986). An amount of 1 ml of extracts were added to 2.5 ml 0.2 M phosphate buffer (pH 6.6) and 2.5 ml potassium ferricyanide (1%). The mixtures were incubated at 50 °C for 20 min, after which 2.5 ml trichloroacetic acid (10%) was added. A total of two and one half milliliters of the mixture was taken and mixed with 2.5 ml water and 0.5 ml 1% FeCl3. The absorbance at 700 nm was measured after allowing the solution to stand for 30 min. The FRAP value was expressed in mg trolox equivalent (TE)/g dry weight. Determination of free radical scavenging activity The hydrogen atom or electron donation ability of the corresponding extracts and some pure compounds was measured from the bleaching of purple coloured methanol solution of DPPH. This spectrophotometric assay uses stable radical 2, 2-diphenyl- 1-picrylhydrazyl (DPPH) as a reagent, according to a slightly modified method of Blois (1958). 100 µl of the extracts was added to 2.9 ml of a 0.004% methanol solution of DPPH. After a 120 min incubation period at room temperature, the absorbance was read against a blank at 517 nm. The percentage of inhibition of free radical DPPH by the extracts was calculated as follows:

Inhibition (%) = (Ablank – Asample /Ablank) x 100 Where Ablank is the absorbance of the control reaction (containing all reagents except the test compound), and Asample is the absorbance of the test compound. Statistical analysis Each of the measurements described above was conducted in triplicate and the mean data ± SD (standard deviation) were reported. The data collected were statistically analysed using the Statistical Analysis Software (SAS) package (version 9.1.2 of SAS Institute, Inc. Cary, NC, 2008). Statistically significant differences (p <0.05) in the antioxidant properties of the samples were determined by one way analysis of variance (ANOVA). Duncan Multiple Range Test (DMRT) was used to determine significant differences between the means. Results Total lipid and fucoxanthin content The total lipid (TL) and fucoxanthin content of three different drying temperatures are presented in Table 1. The amount of TL (15.17 mg/g dry-weight) and fucoxanthin content (1.50 mg/g dry-weight) of powder dried at 90 °C were significantly higher (p <0.05) than those dried at 40 °C (10.61 and 0.79 mg/g dry-weight, respectively), and at 65 °C (12.66 and 1.09 mg/g dry-weight, respectively). The amounts of TL content among all treatment are between 10.6 to 15.2 mg/g dry-weight. These results in agreement with the results obtained from one of two species of Malaysian brown seaweeds, Sargassum binderi (16.60 mg/g dry-weight) compared to Sargassum duplicatum (21.30 mg/g dry-weight) that have been reported by Dedi et al. (2011). The fucoxanthin content from this study was also similar with the result obtained for S. binderi (0.73 mg/g dry-weight) and S. duplicatum (1.01 mg/g dry-weight) that was reported by Dedi et al. (2011). In addition, the HPLC chromatogram of


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fucoxanthin from Sargassum sp. extract at different drying temperature showed only one major peak with a retention time of about 4.2 min (Figure 1). Total phenolic content Phenolic compounds can contribute mainly to the overall antioxidant capacity. Phenolic compound can exhibit antioxidant activity by inactivating lipid free radicals or preventing decomposition of hydroperoxides into free radicals (Pokorny 2001). Marine seaweed extracts, especially polyphenols, have high antioxidant activities (Hong-Yu et al. 2010). The Folin-Ciocalteau method is a rapid and widely-used assay to investigate the total phenolic content but different phenolic compounds have different responses to this method (Kahkonen et al. 1999).

The TPC values summarised in Table 2 were quantified by using Folin Ciocalteau method with gallic acid standard curve, adjusted to a linear equation y = 5.7657x - 0.0242 with a coefficient of correlation R2 = 0.9998. Seaweed powder dried at 90 °C for non-boiled and boiled water extract was found to have the highest TPC (2.75 mg GAE/g dry-weight and 1.13 mg GAE/mg dry-weight, respectively) compared to those dried at 40 °C or 65 °C, even though there is no significant difference (p <0.05) between the powders dried at 65 °C and 90 °C for boiled water extract. Antioxidant activity assay Ferric reducing antioxidant power (FRAP) The AOA for FRAP assay was determined based on the ability of the antioxidant components in the samples to reduce ferric (III) to ferrous (II) in a redox-linked colourimetric reaction (Li et al. 2006) that involves single electron transfer. Table 3 shows that powder extract dried at 90 °C had the highest ability for reducing Fe3+ for both

non-boiled and boiled water extracts with mean values 9.19 and 17.05 mg TE/g dry weight, respectively, compared to powder dried at 40 °C (7.81 and 15.04 mg TE/g dry-weight, respectively) or (65 °C 8.57 and 16.49 mg TE/g dry-weight, respectively).

However, there was no significant different (p <0.05) between powder dried at 65 °C and 90 °C for boiling water extracts as was the TPC. Nevertheless, the reducing ability of boiled water extract for all treatments increased more than 50% compared to non-boiled water extracts.

DPPH radical scavenging The main characteristic of an antioxidant is its ability to trap free radicals. DPPH is widely used to test the ability of the antioxidative compounds functioning as proton radical scavengers or hydrogen donors (Singh and Rajini 2004). The percentage scavenging activity of each extract against DPPH is shown in Table 3. Significant differences in the activities among powder at different drying temperature were observed within non-boiled and boiled water extracts. The powder of Sargassum sp. dried at 90 °C indicated strong free radical scavenging effects for non-boiled and boiled water extracts (18.75% and 81.24% respectively). The lowest percentage of free radical scavenging was observed for the powder dried at 40 °C for both non-boiled (10.54%) and boiled water extract (73.57%). However, there was no significant difference between boiling water extracts of powders dried at 65 °C (80.27%) and 90 °C (81.24%). However there was an increase about 80% of scavenging activity for boiled water extracts compared to non-boiled extract.


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Table 1. Total lipid and fucoxanthin content of Sargassum sp. dried powder under different temperatures

Data was expressed as mean ± SD, each value is a mean of triplicate reading. Means with the same letter are not significantly different ( p >0.05)

Oven drying temperature (°C)

Total lipid (mg/g dry weight)

Fucoxanthin content (mg/g dry weight)

40 10.61 ± 0.26c 0.79 ± 0.03c

65 12.66 ± 0.62b 1.09 ± 0.02b

90 15.17 ± 0.61a 1.50 ± 1.11a

Figure 1. HPLC chromatogram of fucoxanthin from Sargassum sp. extract at three different drying temperatures


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Table 2. TPC values of non-boiled and boiled of seaweed aqueous extract expressed as gallic acid equivalent (GAE)

Data was expressed as mean ± SD, each value is a mean of triplicate reading (n = 3). Means within a column with the same lower case letters are not significantly different (p >0.05). Means within a row with the same upper case letters are not significantly different (p >0.05)

Table 3. AOA values of non-boiled and boiled of aqueous extract of Malaysia brown seaweed, Sargassum sp.

Data was expressed as mean ± SD, each value is a mean of triplicate reading (n = 3). Means within a column with the same lower case letters are not significantly different (p >0.05). Means within a row with the same upper case letters are not significantly different (p >0.05)

Oven drying temperature (°C) TPC (mg GAE/g dry-weight)

Non-boiled Boiled

40 0.97 ± 0.03bB 2.52 ± 0.11bA

65 1.05 ± 0.07abB 2.72 ± 0.03aA

90 1.13 ± 0.02aB 2.75 ± 0.02aA

Oven drying temperature (°C)

Antioxidant activity (AOA)

FRAP (mg TE/g dw) DPPH (% inhibition)

Non-boiled Boiled Non-boiled Boiled

40 7.81 ± 0.48bB 15.04 ± 0.64bA 10.54 ± 1.41cB 73.57 ± 0.32bA

65 8.57 ± 0.23abB 16.49 ± 0.28aA 13.77 ± 0.50bB 80.27 ± 2.25aA

90 9.19 ± 0.43aB 17.05 ± 0.66aA 18.75 ± 1.09aB 81.24 ± 4.51aA


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Discussion Phenolic compounds structurally involve an aromatic ring that bears one or more hydroxyl substituents; they range from simple phenolic molecules to highly polymerised compounds. Despite this structural diversity, the group of compounds is often referred to as polyphenols. Different authors indicate wide variations between the total phenolic content of different fruits or even for the same fruit. These differences may be due to the complexity of these groups of compounds as well as the methods of extraction and analysis (Jessica Lopez et al. 2013). Polyphenols such as phlorotannins (Zou et al. 2008) and carotenoid pigments such as fucoxanthin (Airanthi et al. 2011) are two of bioactive compounds which have been isolated and identified from brown seaweeds. Fucoxanthin and phlorotannins have been identified as active antioxidant compounds from Hijika fusiformis (Yan et al. 1999) and Sargassum kjellamanianum (Yan et al. 1996), respectively. The phenol rings in polyphenolic compounds act as electron traps and are responsible for the multifunctional antioxidant properties such as scavenging of hydroxyl radicals, peroxy radicals or superoxides. A high correlation between the total phenolic content and antioxidant activity has reported by many researchers (Athukorala et al. 2003; Chew et al. 2008; Rajauria et al. 2010; Siriwardhana et al. 2003 and Wang et al. 2009).

The present study was focused on the influence of different oven drying temperature on the fucoxanthin content, TPC and AOA of Malaysian brown seaweed, Sargassum sp. According to Mrad et al. (2012), a decrease in TPC during drying can also be attributed to the binding of polyphenols with other compounds (proteins) or to alterations in the chemical structure of polyphenols which cannot be extracted or determined by available methods. It is generally considered that drying and extraction at a high temperature

will lead to a degradation of some bioactive compounds. However some researchers have demonstrated that this is not always true, especially with regard to the polyphenols with antioxidant activity. Rajauria et al. (2010) investigated the effect of heat processing on the level of phenolic compounds and antioxidant capacity of three species of edible brown seaweeds from Ireland. It was found that the overall antioxidant capacities of all seaweeds tested have been increased. This study was in agreement with our findings. From our study, results showed that higher temperature resulted in a substantial increase in certain phytochemical contents. An increment of drying temperature from 40 °C to 90 °C has increased fucoxanthin content, TPC, ferric reducing ability and DPPH radical scavenging assay. All AOA also have increased in boiled seaweed dried powder (SDP) as compared to non-boiled SDP during extraction process. The formation of phenolic compounds at high temperatures (i.e., 90 °C) might be due to the availability of phenolic precursor molecules through non-enzymatic interconversion between phenolic molecules (Jessica Lopez et al. 2013). As described by Durling et al. (2007) and Silva et al. (2007) in their previous reports, increasing the extraction temperature has been found to enhance the recovery of phenolic compounds. The mechanism that maybe occur during extraction is that the higher temperature will promotes solvent extraction by enhancing both diffusion coefficients and the solubility of polyphenol content (Wan et al. 2011). In addition, increasing extraction temperature will contribute to the release of bound polyphenols in plants with the breakdown of cellular constituents of plant cells which leads to increased cell membrane permeability. Moreover, release of these bound polyphenols could further reduce the chances of those polyphenols to coagulate with lipoprotein. Thereby, enhancing


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solubility of polyphenols and inhibiting coagulation with lipoprotein will increase polyphenols yield (Wan et al. 2011).

Effects of heat processing on fucoxanthin pigments from Sargassum sp. might also contributed to these findings. Like other carotenoids, fucoxanthin is a fat soluble compound. Fucoxanthin has an unusual allenic bond and 5,6-monoepoxide in its molecule that contribute to its unique structure. Isomerisation is a common feature of carotenoids due to the presence of conjugated double bonds in their structures. Factors that contribute to cis-trans isomerisation are light, thermal energy, chemical reactions and interaction with biological molecules such as proteins. Generally the trans isomers of carotenoids are more common in foods and are more stable as compared to their cis counterparts (Nakazawa et al. 2009). During drying process, there are several factors that can affect fucoxanthin content such as degradation of all-trans and cis-isomer fucoxanthin, isomerisation from all-trans to cis-isomer fucoxanthin, and more efficient extraction of fucoxanthin from the seaweed matrix. High temperature can break down cell walls and release more fucoxanthin from seaweed matrix. Therefore, by releasing more fucoxanthin content during drying and extraction, the antioxidant capacity that may be related to the amount of fucoxanthin and TPC will be increased since both of these compounds act as scavengers of the free radicals produced during oxidation reactions (Di Scala et al. 2011).

These mechanisms can be equated with the study on lycopene content as reported by Shi et al. (2008). Lycopene may be expected to undergo two major changes during processing and storage: isomerisation from all-trans to mono-cis or poly-cis forms and oxidation. The all-trans-isomer of lycopene is the most predominant geometrical isomer in fruits and vegetables (about 94 – 96% of total lycopene in red

tomato fruit) and is the most thermodynamically stable form. One of the possible reasons for this trend could be the effect of extractability of lycopene in tomato matrix. The tomato cell walls were not completely disrupted during the tomato puree preparation. Therefore, for the cells that were disrupted, lower temperatures (as 80 °C) could be enough to release lycopene. On the other hand, for the cells that were not disrupted during the puree preparation, for example, the cells of tomato skin, a longer heating treatment time or higher temperature may be needed to disrupt the cell walls sufficiently to release most of the lycopene from cells. Therefore, longer heating time at 100 °C, or higher temperature (120 °C) may increase the extraction yield of lycopene in tomato puree (Shi et al. 2008).

According to Anese et al. (1999), heating tomato juice at 95 °C for more than 3 or 4 h had increased the antioxidant potential of the juice due to the formation of Maillard reaction products (MRP), which have antioxidant activity. The protective effect of MRP could be another possible reason for the increase of lycopene during the 100 °C heating treatment. Maillard reaction will also to be considered for another factors contributed to our findings. Besides that, the increasing temperature could also be related to the developmental changes and wound-like response due to drying. Dixon and Paiva (1995) reported that plants respond to wounding with increase in phenolic compounds, which involved in the repair of wound damage. The generation and accumulation of compounds with a varying degree of antioxidant activity during heat processing could also develop antagonistic or synergistic effects between themselves or with the other constituents, which could be another possible reason for the increasing on certain phytochemical during heat processing. These complex chemical interactions that influence functional


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properties of Sargasssum sp. during drying and extraction at high temperature need to be further investigated. Conclusion The study showed that the polyphenol and antioxidant activities of seaweed Sargassum species from Semporna Sabah, Malaysia were influenced by different drying temperatures. Fucoxanthin, TPC and antioxidant activities were found high if dried at higher temperature. The increasing of FRAP and DPPH-RSA were proportional to TPC. The highest phenolic content and antioxidant activity was found in the seaweed which dried at 90 °C and extracted with boiled water. High phytochemical content at high drying temperature (90 °C) could be an important starting step for seaweed processing. With the ascertained antioxidant activity of this brown seaweed, optimisation on the extraction conditions from Sargassum sp. should be carried out by using response surface methodology (RSM). Acknowledgement The author acknowledges with gratitude the financial support given by Malaysian Agricultural Research and Development Institute (MARDI) and special thanks to the Seaweed Downstream Research Centre (SDRC) and School of Chemical Sciences and Food Technology, Faculty of Science and Technology, UKM for this opportunity. References Airanthi, M.K.W.A., Hosokawa, M. and Miyashita,

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Abstrak Kajian ini dijalankan untuk menilai pengaruh suhu pengeringan yang berbeza ke atas kandungan fukozantin, kandungan fenolik dan aktiviti antioksidan pada rumpai laut perang Malaysia, Sargassum sp. Rumpai laut perang dikeringkan pada suhu 40, 65 dan 90 °C. Semua serbuk rumpai laut kering diukur jumlah lipid dan kandungan fukozantin. Ekstrak air tanpa didih dan didih pula dianalisis untuk jumlah kandungan fenolik (TPC) menggunakan kaedah Folin-Ciocalteu dan aktiviti antioksida menggunakan asai aktiviti penurunan antioksidan ferric serta skaveng radikal 2, 2-phenyl-1-picrylhydrazil. Keputusan yang diperoleh daripada kajian ini menunjukkan bahawa peningkatan suhu pengeringan, kandungan fukozantin, TPC dan juga aktiviti antioksidan rumpai laut perang kering ini juga turut meningkat secara signifikan (p <0.05) pada ekstrak yang dididih. Rumpai laut perang yang dikeringkan pada suhu 90 °C memberikan kandungan fukozantin dan aktiviti antioksidan yang paling tinggi.

effect of drying temperature on the content of fucoxanthin...

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