The effect of processing conditions on the properties of gelatin from skate (Raja kenojei) skins. Food Hydrocoll

Department of Animal Science, Chonnam National University, 300 Yongbong-dong Buk-gu, Gwangju 500-757, South Korea
Food Hydrocolloids (Impact Factor: 4.09). 08/2006; 20(6):810-816. DOI: 10.1016/j.foodhyd.2005.08.002


Effects of several conditions (liming concentrations, extraction solution pH, extraction temperature and extraction time) to extract gelatin from skate skin on the yield and quality properties were investigated. The optimum conditions for gelatin extraction are as follows; place skin in a lime solution of 1.5% (w/v) calcium hydroxide, extract with three volumes of water (pH 6.0) for 4 h at 50%, filter gelatin through activated carbon (250–350 mesh, 3%) and freeze-dry the colloidal suspension. The functional properties of skate skin gelatin produced by optimum extraction conditions were: gelling point 16.12 °C; melting point 19.30 °C; isoelectric point 6.45; and turbidity 6.98.

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Available from: Koo Bok Chin, Jul 28, 2015
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    • "Hence, during our final step of collagen conversion to gelatin, the extraction temperature was kept at 40‒45°C in order to achieve a controlled partial hydrolysis of cross-links and peptide bonds in the original collagen structure. Furthermore, yields at 50°C of extraction have been reported to be better than those at 40°C, even though the quality is lower at 50°C of extraction (Cho et al., 2006). "
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    • "Processing techniques used for skin gelatin production have been reported, such as thermal treatment, acid-alkaline extraction, enzymatic aided, and also other emerging technologies (high-pressure treatment, ultrasonic , and microwave heating). Gelatins have been produced from various fish species such as Nile perch skin and bone (Muyonga et al. 2004a), skate skin (Cho et al. 2006), bigeye snapper and brownstripe red snapper skin (Jongjareonrak et al. 2006), and giant catfish skin (Jongjareonrak et al. 2010). Gelatin extracted with enzymes from skins of different fish species such as sin croaker and shortfin scad (Cheow et al. 2007); bigeye snapper and brownstripe red snapper (Jongjareonrak et al. 2006; Benjakul et al. 2009; Nalinanon et al. 2007, 2008) have all been investigated. "
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    • "Currently, increasing the extraction temperature in order to increase the yield of gelatin extraction, even in detriment of quality, is a common practise in the gelatin extraction procedures (Johnston-Banks, 1990). This practise is especially applied in gelatins obtained from mammalian sources such as pig skins or cow hides, which are the most available gelatins nowadays (Gómez- Guillén et al., 2002), but it may be also applied to fish gelatin extraction (Cho et al., 2006). For this reason, specific studies are needed for each type of gelatin. "
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