Afonso, Clélia

Augusto, Ana

Mendes, Susana

Mouga, Teresa

Nunes, Paulo M.

English

IC-online

INTRODUCTIONMATERIAL & METHODSSeaweeds have increasingly been used as food due to their rich chemicaland nutritional composition, particularly as high supply of essentialnutrients to the human body such as protein, minerals, vitamins anddietary fiber and non-nutrient components such as polyphenols.However, the availability of fresh seaweeds is scarce and drying methodshave been used to stabilize and preserve these products. As such, it is ofcrucial importance to understand how the drying conditions may affectthe properties of seaweeds.OBJECTIVES:The aim of this study was to understand the effect of different dryingconditions, dry-bulb temperature of 40 °C and 60 °C, on several seaweedsspecies from the coast of Peniche: Fucus spiralis, Codium tomentosum andCorallina officinalis. The effect of drying temperatures on thephytochemical compounds of seaweed was also evaluated.Fresh Fucus spiralis, Codium tomentosumand Corallina officinalis samples werecollected from Peniche coast (Fig. 1),Portugal and stored at -20°C until analysis.RESULTSDried seaweeds characterization:• Moisture content (AOAC, 2000)• Water activity• Color measurement ∆E* = √( ∆a 2 + ∆b2 + ∆L2)CONCLUSIONSAna Augusto1, Paulo M. Nunes1, Susana Mendes1, Clélia Afonso1, Teresa Mouga1*1. MARE – Centro de Ciências do Mar e do Ambiente, ESTM, Instituto Politécnico de Leiria* Corresponding author: mougat@ipleiria.ptEffect of different drying temperatures on the moisture, content of phytochemical constituents and technological properties of Peniche coast seaweedsReferences:Augusto, A., Simões, T., Pedrosa, R., Silva, S.F.J. (2016). Evaluation of seaweed extracts functionality as post-harvest treatment for minimally processed Fuji apples. Innovative Food Science and Technologies, 33, 589-595. Maskan, M. (2001). Drying, shrinkage and rehydration characteristics of kiwifruits during hot air and microwave drying. Journal of Food Engineering, 48, 177-182.Sakthivel, R., Devi, K.P. (2015). Evaluation of physicochemical properties, proximate and nutritional composition of Gracilaria edulis collected from Palk Bay. Food Chemistry, 174, 68-74. Seremet, L., Botez, E., Nistor, O.-V., Andronoiu, D.G. (2016). Effect of different drying methods on moisture ratio and rehydration of pumpkin slices. Food Chemistry, 195, 104-109.Wang, T., Jónsdóttir, R., Ólafsdóttir, G. (2009). Total phenolic compounds, radical scavenging and metal chelation of extracts from Icelandic seaweeds. Food Chemistry, 116, 240–248. Drying procedure: Hot air dryingSamples were dried at two different temperatures using a Tray drier (Fig.2): 40°C(0.99 m.s-1 air velocity, relative humidity of 23%) and 60 °C (0.99 m.s-1 air velocity,relative humidity of 11.75%) until they reached constant weight. The finalmoisture content of each sample was measured in order to calculate the moistureat each weighing interval. Drying tests were replicated ten times at each inlet airtemperature and averages are reported.• According to Sakthivel and Devi, 2015. Water holding capacity (WHC)• According to Sakthivel and Devi, 2015.Oil holding capacity(OHC)• According to Sakthivel and Devi, 2015. Swelling capacity (SWC)• Rehydration ratio (RR) according to Seremet et al., 2016.• Rehydration capacity represented as percentage of water gain according to Maskan et al., 2001.Rehydration analysisExtraction and phytochemicals determination:• The extraction of phenolic compounds from seaweeds was carried out withwater/ethanol (3:1 w/v) solution (Augusto et al., 2016).• Total phenolic content, DPPH free radical-scavenging activity and oxygenradical absorbance capacity (ORAC) (Augusto et al., 2016; Wang et al., 2009).Technological properties:Figure 1. Peniche satellite view, 39°22'11.4"N 9°23'10.2"W.  Figure 2. Tray drier.  Figure 3.  Typical drying curves for (a) Fucus spiralis, (b) Corallina officinalis and  (c) Codium tomentosum at 40 °C and 60 °C.• The shortest drying times were obtained using a dry-bulb temperature of 60 °C(Fig.3).• Drying process at 60 °C allowed to obtain seaweeds with both lower moisturecontent and water activity (Fig.3).F. spiralis C. officinalis C. tomentosumFresh seaweedsAfter drying at 60°C∆E 11.44 ± 4.40 15.95 ± 2.74 4.31 ± 2.23After drying at 40 °C∆E 13.06 ± 4.49 13.06 ± 4.49 3.86 ± 2.92• Drying temperatures and dried seaweeds characterization was performed inthe present work. Also technological properties of dried seaweeds werestudied to achieve the best drying temperature.• In this work, it was concluded that higher drying temperature conditions havehigher impact on the studied parameters, possibly due to a higher physical andchemical damage in the algae tissues.Dried seaweedEffect of drying temperatures in  technological properties of dried seaweedsWHC OHC SWC RehydrationanalysisFucus spiralis Higher values at 40 °C drying.Higher values at 40 °C drying. No effect. No effect.Corallinaofficinalis No effect. No effect.Higher values at 60 °C drying. No effect.Codiumtomentosum No effect. No effect.Higher values at 60 °C drying. No effect.Table 1. Color changes and photos of fresh and dried seaweeds.• The drying process has no significant effect on phytochemicals compounds.• The dried seaweed instrumental color showed lower values of L*compared to freshsamples (Table 1).• The drying of Corallina officinalis at 60 °C causes the highest color changes (Table 1).Acknowledgements: This study had the support of Fundação para a Ciência e Tecnologia (FCT), through the strategic project UID/MAR/04292/2013 granted to MARETable 2. Effect of drying temperatures in studied technological properties of dried seaweeds. 

Effect of different drying temperatures on the moisture, content of phytochemical constituents and technological properties of Peniche coast seaweeds

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Effect of different drying temperatures on the moisture, content of phytochemical constituents and technological properties of Peniche coast seaweeds

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