The objective of this study was to examine the effect of ginger extract (GE) combined with citric acid on the tenderness of duck breast muscles. Total six marinades were prepared with the combination of citric acid (0 and 0.3 M citric acid) and GE (0, 15, and 30%). Each marinade was sprayed on the surface of duck breasts (15 mL/100 g), and the samples were marinated for 72 h at 4℃. The pH and proteolytic activity of marinades were determined. After 72 h of marination, Warner Bratzler shear force (WBSF), myofibrillar fragmentation index (MFI), pH, cooking loss, moisture content, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and protein solubility were evaluated. There was no significant (p>0.05) difference in moisture content or cooking loss among all samples. However, GE marination resulted in a significant (p<0.05) decrease in WBSF but a significant (p<0.05) increase in pH and MFI. In addition, total protein and myofibrillar protein solubility of GE-marinated duck breast muscles in both WOC (without citric acid) and WC (with citric acid) conditions were significantly (p<0.05) increased compared to non-GE-marinated duck breast muscles. SDS-PAGE showed an increase of protein degradation (MHC and actin) in WC condition compared to WOC condition. There was a marked actin reduction in GE-treated samples in WC. The tenderization effect of GE combined with citric acid may be attributed to various mechanisms such as increased MFI and myofibrillar protein solubility.

Duck feet gelatin (DFG) gel was added as a fat replacer to low-fat frankfurters and the effect of DFG on physicochemical, textural, and sensory characteristics of low-fat frankfurters was evaluated. DFG gel was prepared with a 20% duck feet gelatin concentration (w/w). Adding DFG decreased lightness and increased yellowness of the low-fat frankfurters (p<0.05). However, DFG did not affect redness of low-fat frankfurters (p>0.05). The statistical results indicated that adding DFG improved cooking yield of low-fat frankfurters (p<0.05). In addition, replacing pork back fat with DFG resulted in increased moisture content, protein content, and ash content of low-fat frankfurters, and the low-fat frankfurter formulated with 5% pork back fat and 15% DFG gel had the highest moisture content and lowest fat content (p<0.05). Adding of DFG increased all textural parameters including hardness, springiness, cohesiveness, chewiness, and gumminess of low-fat frankfurters (p<0.05). In terms of sensory properties, the low-fat frankfurter formulated with 5% pork back fat and 15% DFG gel showed similar satisfaction scores for the flavor, tenderness, juiciness, and overall acceptance when compared to the regular frankfurters (20% back fat). Therefore, our results suggest that DFG could be an effective novel source, as a fat replacer, for manufacturing of low-fat frankfurters.

This study evaluated the effects of adding glasswort hydrate containing non-meat ingredient (GM, carboxy methyl cellulose; GC, carrageenan; GI, isolated soy protein; GS, sodium caseinate) on the quality characteristics of reduced-salt, reduced-fat frankfurters. The pH and color evaluation showed significant differences, depending on the type of glasswort hydrate added (p<0.05). In the raw batters and cooked frankfurters, the addition of glasswort hydrate decreased the redness and increased the yellowness in comparison with frankfurters without glasswort hydrate. The reduction in salt and fat content significantly increased cooking loss and decreased hardness, tenderness and juiciness (p<0.05). Glasswort hydrate containing non-meat ingredient improved cooking loss, water holding capacity, emulsion stability, hardness, and viscosity of reduced-salt, reduced-fat frankfurters. The GM treatment had the highest myofibiliar protein solubility among all treatments, which was associated with emulsion stability and viscosity. The GC treatment had higher values for all texture parameters than the control. In the sensory evaluation, the addition of glasswort hydrate with non-meat ingredient improved tenderness and juiciness of reduced-salt, reduced-fat frankfurters. GM, GC, and GI treatments improved not only the physicochemical properties but also the sensory characteristics of reduced-salt, reduced-fat frankfurters. The results indicated that the use of glasswort hydrate containing non-meat ingredient was improved the quality characteristics of reduced-salt, reduced-fat frankfurters.