Effect of tannic acid and kiam wood extract on lipid oxidation and textural properties of fish emulsion sausages during refrigerated storage Sajid Maqsood a , Soottawat Benjakul b,⇑ , Amjad Khansaheb Balange c a Department of Food Science, Faculty of Food and Agriculture, United Arab Emirates University, Al-Ain 17551, United Arab Emirates b Department of Food Technology, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand c Department of Fish Processing Technology and Microbiology, College of Fisheries, Dr. Balasaheb Sawant Konkan Krishi Vidyapeeth, Dapoli, Ratnagiri, Maharashtra, India article info Article history: Received 20 November 2010 Received in revised form 30 April 2011 Accepted 18 July 2011 Available online 22 July 2011 Keywords: Striped catfish Emulsion sausages Tannic acid Kiam extract Lipid oxidation abstract Effect of tannic acid (0.02% and 0.04%) and ethanolic kiam wood extract (EKWE) (0.04% and 0.08%) on lipid oxidation and textural properties of fish emulsion sausages during 20 days of refrigerated storage was investigated. Control samples (C) had the highest peroxide value (PV) and thiobarbituric acid-reac- tive substances (TBARS) value up to day 16 and 8 of storage, respectively. With the addition of tannic acid and EKWE, PV and TBARS values in the sausages were retarded effectively, compared to the control (P < 0.05), especially when the tannic acid and EKWE at higher level were used. At the same level, EKWE showed the lower ability in retarding the lipid oxidation, in comparison with tannic acid. Tannic acid at both levels (0.02% and 0.04%) was also effective in retarding the formation of fishy odour in the samples throughout the storage, compared to the control and EKWE treated samples (P < 0.05). Both tannic acid and EKWE had no detrimental effect on the sensory attributes of sausages. However, EKWE treated sam- ple had lower L / and higher a / and DE / values, compared to the control samples (P < 0.05). After 20 days of storage, the sample added with 0.04% tannic acid had higher hardness, gumminess and chewiness, compared with others (P < 0.05). Samples added with 0.04% tannic acid also displayed more compact structure with no visible voids. Furthermore, oil droplets with smaller size were dispersed more uni- formly, compared to others. Thus, tannic acid (0.02% and 0.04%) and EKWE (0.08%) were effective in retarding lipid oxidation and fishy odour development as well as could maintain the textural properties of fish emulsion sausages during the refrigerated storage of 20 days. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction Emulsion sausages, such as frankfurter, are widely consumed in both Western and Asian countries. A product is typically made of beef, pork, or chicken and contains the fat by 25–30%. Fish mince and surimi have recently been used as a raw material for emulsion sausage production, particularly in Asian countries (Konno, 2005). Marine fish are generally a rich source of n3 polyunsaturated fatty acids (PUFA) containing approximately 14–30% of total fatty acids, whereas PUFA in freshwater fish was only 1–11% of total fatty acids (Rahman, Huah, Hassan, & Daud, 1995; Steffens, 1997). Biological importance of n3 PUFA, particularly eicosapen- taenoic acid (EPA) and docosahexaenoic acid (DHA), on brain and retina development, has been realized (Simopoulos, 1997). An in- crease in consumption of n3 PUFA has been reported to reduce the risk of coronary heart disease, decrease mild hypertension and prevent certain cardiac arrhythmias (Garg, Wood, Singh, & Moughan, 2006). Fish oil is actually the main dietary source of n3 PUFA. The World Health Organization (WHO Study Group, 2003) recommends regular fish consumption to provide approxi- mately 200–500 mg per week of EPA and DHA and replacement of saturated fat by monounsaturated counterpart. Fortification of marine fish oil rich in n3 PUFA to the fresh water fish sausage could be an alternative means to improve its fat quality and to increase n3 PUFA consumption. However, mar- ine fish oil is susceptible to lipid oxidation, thereby negatively affecting flavour, odour, colour, texture, and the nutritional value of fish products (Frankel, 1998). To retard such a quality loss, syn- thetic antioxidants have been used to decrease lipid oxidation dur- ing the processing and storage of fish and fish products (Boyd, Green, Giesbrecht, & King, 1993). However, the use of synthetic antioxidants has raised questions regarding safety and toxicity (Chang, Ostric-Matijasevic, Hsieh, & Chang, 1977). The use of natu- ral antioxidants is emerging as an effective means for controlling lipid oxidation and limiting its deleterious consequences. Recently, Maqsood and Benjakul (2010a, 2010b, 2010c) reported that tannic acid exhibited the superior radical scavenging activities as well as reducing power and effectively inhibited the lipid oxidation in fish 0308-8146/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodchem.2011.07.065 ⇑ Corresponding author. Tel.: +66 7428 6334; fax: +66 7455 8866. E-mail addresses: sajid.m@uaeu.ac.ae (S. Maqsood), soottawat.b@psu.ac.th (S. Benjakul). Food Chemistry 130 (2012) 408–416 Contents lists available at ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem