title: Effect of nanogrinding on the pigment and bioactivity of Djulis ( Chenopodium formosanum Koidz.).
abstract: Betanin is an antioxidant pigment found in djulis, a grain native to Taiwan, and is a natural source food coloring, but the bright red color degrades rapidly if submitted to light, heat, or oxygen. The effects of nanogrinding on the stability of pigments and bioactive components are unknown. In this study, the color characteristics and bioactivity (antioxidant capacity and enzyme activity) of nanoparticle (NP) djulis was compared with those of intact granules (IG) and microparticles (MP). Results showed that the NP samples exhibited the highest betanin content (2.04 mg/g), which was almost twice that of IG. It was observed that nanogrinding resulted in higher pigment extraction efficiency. However, during storage (5-35 °C for 56 days), NP samples showed the most serious pigment degradation, and this color degradation, as expected, had the lowest activation energy. This was more evident when the storage temperature was high. Antioxidant capacities showed the same trends. MP and NP exhibited significantly higher activity of superoxide dismutaste-like activity, lactoperoxidase (LPO), and lysozyme than IG. Gel permeation chromatography confirmed the degradation of larger particles during nanogrinding, which might favor enzyme extraction and their activities. Statistical analysis revealed a close relationship between betanin and antioxidant capacity.
authors.affiliation: Department of Food Science, National Pingtung University of Technology and Science , 1 Hsueh Fu Road, Nei-Pu Hsiang, 91207 Pingtung, Taiwan, Republic of China.
authors.forename: Pi-Jen
authors.initials: PJ
authors.lastname: Tsai
authors.forename: Yuh-Shuen
authors.initials: YS
authors.lastname: Chen
authors.forename: Chih-Hung
authors.initials: CH
authors.lastname: Sheu
authors.forename: Chin-Yen
authors.initials: CY
authors.lastname: Chen
mesh_terms: D000975:Antioxidants / Q000032:analysis; D050859:Betacyanins / Q000032:analysis; D027462:Chenopodium / Q000737:chemistry*; D004355:Drug Stability; D005511:Food Handling / Q000379:methods*; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry; D010316:Particle Size; D010860:Pigments, Biological / Q000737:chemistry*; D012639:Seeds / Q000737:chemistry*; D013997:Time Factors
chemical_list: D000975:Antioxidants; D050859:Betacyanins; D010860:Pigments, Biological; C020228:betanin