Department of Biological Sciences, Escola Superior de Agricultura 'Luiz de Queiroz' - University of Sao Paulo, Pádua Dias 11, 13.418-900 Piracicaba, Sao Paulo, Brazil.
Department of Biological Sciences, Escola Superior de Agricultura 'Luiz de Queiroz' - University of Sao Paulo, Pádua Dias 11, 13.418-900 Piracicaba, Sao Paulo, Brazil.
Food Chem. 2019 Jul 15;286:600-607. doi: 10.1016/j.foodchem.2019.02.040. Epub 2019 Feb 19.
This study investigated the effectiveness of cysteine in conservation of bioactive compounds and the antioxidant capacity of minimally processed red beet. After red beet minimal processing increasing cysteine concentrations were applied, corresponding to control, 2 mM, 4 mM, 8 mM and 16 mM. Assay was performed over 15 d to evaluate the polyphenols, betalains, antioxidant capacity and enzymatic activity of polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL). Cysteine enhanced the gallic acid, caffeic acid, chlorogenic acid, kaempferol and betalain contents until 6 d of storage. Subsequently, dosages of cysteine above 4 mM maintained gallic acid, kaempferol and betalains contents. Cysteine appears to influence the phenylpropanoid pathway, favoring the accumulation of polyphenols and betalains. In red beet, cysteine did not inhibit PPO activity but enhanced PAL activity. Betalains contribute more than phenolics to the antioxidant capacity, and their relationship with cysteine has not been thoroughly elucidated to date.
本研究探讨了半胱氨酸在保持最小加工红甜菜生物活性化合物和抗氧化能力方面的有效性。在最小化红甜菜加工过程中，应用了增加半胱氨酸浓度的方法，对应于对照、2mM、4mM、8mM 和 16mM。在 15d 的时间内进行了测定，以评估多酚、甜菜碱、抗氧化能力和多酚氧化酶 (PPO) 和苯丙氨酸解氨酶 (PAL) 的酶活性。半胱氨酸增强了没食子酸、咖啡酸、绿原酸、山奈酚和甜菜碱的含量，直到储存 6d。随后，4mM 以上的半胱氨酸剂量维持了没食子酸、山奈酚和甜菜碱的含量。半胱氨酸似乎影响了苯丙烷途径，有利于多酚和甜菜碱的积累。在红甜菜中，半胱氨酸没有抑制 PPO 活性，而是增强了 PAL 活性。甜菜碱对抗氧化能力的贡献大于酚类，其与半胱氨酸的关系尚未得到充分阐明。
