Effects of tea polyphenols on the processing of fresh-cut crisp yam cubes
To clarify the color protection and antibacterial effects of tea polyphenols(white)on fresh-cut crisp yam,five different concentrations of tea polyphenols solutions were perpared and soaked for 5 min on crisp yam,with water and conventional treatments(sodium hypochlorite)as controls.The weight loss rate,browning degree,aerobic plate count and Escherichia coli MPN value of fresh-cut crisp yam cubes were detected regularly,and the sensory quality was scored.The results showed that compared with the control,under 4 ℃ condition,all the five different concentrations of tea poly-phenols could delay the oxidative browning of crisp yam,reduce the browning degree,maintain good appearance quality and commerciality,and extend the shelf life to more than 7 days.Among them,0.20%tea polyphenol had the best preser-vation effect on fresh-cut crisp yam,with good sensory quality,the preservation of 11 d,the bacteriostasis period of 12 d,the browning degree of 5.46%,the total number of colonies of 2.17×104 CFU·g-1 and the MPN value of Escherichia coli less than 3.0.In actual production,different concentrations of tea polyphenols can be selected according to the require-ments of shelf life.The results provide manufacturers an option to use natural preservatives instead of chemical preserva-tives in the processing of fresh-cut crisp yam.