Effect of Konjac Powder on the Quality of Deep-fried Battered Yam Strips

To investigate the effect of konjac powder addition on the properties of batter, edible quality, and flavor characteristics of fried battered yam strips, this study used indicators such as water retention, sedimentation, viscosity, batter adhesion rate, and the water and oil content, color, and texture of the fried battered yam strips. Sensory evaluation was conducted using the fuzzy mathematics comprehensive evaluation method, and volatile flavor compounds were analyzed using headspace solid-phase microextraction combined with headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). Results showed that as the konjac powder addition increased, the water retention, stability, and batter adhesion rate significantly improved (P<0.05). When the konjac powder addition ranged from 0.3% to 0.5%, the fried battered yam strips exhibited moderate hardness, a soft core, reduced greasiness, and an appealing golden yellow color. The highest sensory score was achieved at 0.3% konjac powder addition, indicating good edible quality. HS-SPME-GC-MS results indicated that when konjac powder addition exceeded 0.4%, the total amount of volatile flavor compounds in the fried battered yam strips decreased. Through relative odor activity value (ROAV) analysis, 25 key flavor compounds were identified, and principal component analysis (PCA) was performed on the 13 key flavor compounds with ROAV≥1. Results showed that at 0.2% konjac powder addition, the key volatile flavor compounds were (E,E)-2,4-decadienal, phenylacetaldehyde, and n-octanal, characterized by prominent nutty, oily, and mushroom flavors. At 0.3% and 0.4% konjac powder addition, the key flavor composition was similar, mainly consisting of lauryl alcohol, linalool, pentanol, 2-ethyl-3,5-dimethylpyrazine, and 3-ethyl-2,5-dimethylpyrazine, with notable nutty, fatty, and floral-fruity aromas. The main flavor contributing compounds at 0.5% addition were n-nonanal, decanal, (E)-2-decenal, and (E)-2-nonenal, with prominent oily, green, fruity, and floral aromas. The sample with 0.6% konjac powder addition had a flavor profile close to the original, with (E,E)-2,4-nonadienal as the main component, exhibiting noticeable fatty and floral aromas. Considering the edible quality, sensory score, and flavor characteristics of the fried battered yam strips, the optimal addition amount of konjac powder was determined to be 0.3%.