Antioxidative characteristics of oils in ground pork‐fat patties cooked with soy sauce

Abstract

Abstract Ground pork‐fat patties were cooked alone (control), with NaCl solution, with NaCl solution containing sucrose, with fermented soybean broth, with fermented black soybean broth, and with commercial soy sauce products at 125°C for 2 h. The top‐layer oils were then stored at 60°C for periodical determinations of conjugated diene hydroperoxide (CDHP) contents. The fermented broth‐cooked and soy sauce‐cooked oils were stable against CDHP formation during storage. This supports the customary impression that soy sauce‐cooked pork is stable against oxidative rancidity. Analysis of the fatty acid compositions showed the presence of linoleic, linolenic, and arachidonic acids, which are susceptible to oxidation. When the fermented brothcooked oils were extracted with methanol, concentrated, and introduced to the control oils for storage, an estimated antioxidative potency close to that of 2 ppm butylated hydroxyanisole was observed. In comparing free amino acid compositions of the fermented soybean and black soybean broths before and after cooking the ground pork‐fat patties, threonine, serine, glutamic acid, alanine, isoleucine, leucine, tryptophan, and tyrosine contents tecreased while proline, valine, histidine, and arginine contents increased.