Extraction of Carrot (Daucus carota) Antifreeze Proteins and Evaluation of Their Effects on Frozen White Salted Noodles

Homogenate and vacuum infiltration-centrifugation were adopted and compared in carrot antifreeze proteins (CaAFPs) extraction, and effects of CaAFPs on thermophysical properties, texture properties, cooking properties, and microstructure of frozen white salted noodles were studied. Results showed that the vacuum infiltration-centrifugation was more targeted than homogenate in CaAFPs extraction, while its protein extraction rate was much lower than homogenate. Differential scanning calorimeter measurement showed that CaAFPs could not only lower the initial point of freezing (Tf) and the end point of freezing (Tm′) of water but also decrease the freezable water content. It also confirmed that CaAFPs were enriched in apoplast extract. The addition of CaAFPs could lower the enthalpy of melting of frozen noodles. V-CaAFPs could lower Tm′ of frozen noodles but the Tm′ of H-noodles was slightly increased. Freezable water content of frozen noodles was decreased by the addition of CaAFPs and Tg″ of them was increased. Texture profile analysis showed that texture properties of white salted noodles were significantly influenced (p < 0.05) by the addition of CaAFPs. Cooking properties of frozen white salted noodles were also significantly enhanced (p < 0.05) by increasing cooking absorption and reducing dry material loss. NMR measurement showed that the addition of CaAFPs could shift water from mobile state to less mobile state. Microstructure of noodles suggested that the addition of CaAFPs could protect the gluten network from the damage caused by freezing and temperature fluctuation, which resulted in an integrated gluten network in white salted noodles.