INHIBITORY EFFECT OF TANNIN IN DIETARY SORGHUM DISTILLERY RESIDUE AND PRELIMINARY TREATMENT WITH POLYETHYLENE GLYCOL ON IN VITRO DIGESTIBILITY OF GREY MULLET (MUGIL CEPHALUS) |
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| Authors: | SHIN-MEI LEE BONNIE SUN PAN |
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| Affiliation: | Department of Food Science National Taiwan Ocean University Keelung, Taiwan, ROC;Department of Food Engineering National Kaohsiung University of Applied Sciences Kinmen, Taiwan, ROC |
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| Abstract: | Sorghum distillery residue (SDR) has antioxidant and blood thinning effect on fish fed during winter, but inhibited their growth. The objective of this study was to eliminate the adverse effect but to maintain the nutraceutical benefits of SDR. The content of tannin in SDR was found to be 3.3 mg/g on dry weight basis. An in vitro digestibility test was developed to simulate the in vivo digestion of grey mullet. The protein digestibility of SDR was 47% lower than that of the control. Inhibition of trypsin activity correlated with the amount of SDR extract (r = 0.98) and decreased significantly (P < 0.05) when the SDR extract was pretreated with polyethylene glycol (PEG), a tannin binding agent. Based on Lineweaver‐Burk plot analysis, the inhibition of SDR on trypsin was of noncompetitive mixed type with changes in both Vmax and Km. A detannin treatment with PEG was tested. This treatment may provide an example to utilize other plant protein sources rich in tannin as fish feed ingredients. |
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