Improving the Lipophilic Antioxidant Activity of Poultry Protein Hydrolisates Through Chemical Esterification

Purpose: Poultry protein hydrolysates (PPHs) are obtained as by-product of poultry slaughter industry using bio catalytic hydrolysis. These protein hydrolysates have good antioxidant properties, which make them potential functional ingredient to prevent the oxidation of meat derived products. However, protein hydrolysates have a poor solubility in lipid media. Methods: To increase the solubilisation in the lipid phase, thus improving antioxidant properties on the fatty acids, several esterification reactions were carried out using different alcohols. The reactions were monitored by LC–MS and the shift in antioxidant activity was assessed with hydrophilic and lipophilic ABTS assay. Results: A good increase in the lipophilicity of the esterified PPHs is shown, proportional to the increase of the alcohol chain length. Accordingly, a significant increase of the lipophilic antioxidant activity, especially for longest chain alcohols, was also observed. Conclusions: These results indicated that the chemical esterification of PPHs with food-grade long chain alcohol can be a valuable approach to increase the lipophilic antioxidant properties of these products. Graphical Abstract: [Figure not available: see fulltext.]

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Not AvailableSoft tissue from cultured farm fresh oysters (Crassostrea madrasensis) was subjected to two standard enzymatic peptide extraction procedures using pepsin and papain. The crude extracts obtained were partially purified by column chromatography and were freeze-dried. The hydrolysates obtained were compared with respect to their degree of hydrolysis (DH), antioxidant potential (AP) and total phenolic content (TPC). The hydrolysate showing better antioxidant property was further subjected to purification by high performance liquid chromatography and characterized by LC-MS/MS. Papain-digested oyster protein (OPHpap) hydrolysate showed higher DH, AP and TPC. OPHpap was further subjected to ultrafiltration and fractionated into 3 sizes namely, above 10, 3–10 and 1–3 kDa according to the molecular size. Antioxidant capacity of\3 kDa fraction OPHpap-3 evaluated by DPPH free radical scavenging assay, metal chelating activity, linoleic acid autoxidation assay showed maximum effectiveness. Of the seven fractions collected by purification of OPH-pap-3 on semi-preparative RP-HPLC, fraction 7 that showed the highest antioxidant activity was further characterized by LC-ESI-MS/MS and its sequence determined. An antioxidant peptide molecule with thirteen amino acids was identified in oyster protein hydrolysate obtained by papain digestion that may find application as a nutraceutical or may be utilized in food industry for prevention of rancidity in foods.Not Availabl