The study evaluated the optimal condition for roasting sweet potato using response surface methodology. Proximate composition, antioxidant activity, volatile compounds, and water migration of roasted sweet potato were also determined. The results revealed that the optimal roasting condition included a roasting time of 40 min, a roasting temperature of 235 °C, and a roasting speed of 40 rad/min, the reducing sugar and vitamin C of roasted sweet potato obtained under optimal condition was 47.79 g/100 g (DW) and 60.25 mg/100 g (DW), respectively. After roasting, starch, protein and vitamin C content of sweet potato were significantly decreased, while total phenolic content and antioxidant activity were increased. 2-Methyl butanal was the main aromatic compound. Low-field NMR indicated that the proportion of free water increased and relaxation times (T2) were decreased after roast process, indicated that the bound water in sweet potato was diffused from inside to outside, thus the texture became softer.
Keywords: Acetic acid (PubChem CID:176); Acetonitrile (PubChem CID:6342); Alpha-d-glucose (PubChem CID:79025); Chlorogenic acid (PubChem CID:1794427); Disodium hydrogen phosphate (PubChem CID:24203); Ethanol (PubChem CID:702); Hydrochloric acid (PubChem CID:313); Moisture migration; Nutritional composition; Response surface methodology; Roasted sweet potato; Sodium carbonate (PubChem CID:10340); Sodium hydroxide (PubChem CID:14798); Sulfuric acid (PubChem CID:1118); Volatile compounds.
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