This study provides a new idea for improving chlorophyll stability and color quality of green leafy vegetables by Zn2+ synergistic HHP. Zn-chlorophyll was prepared with zinc acetate and chlorophyll under HHP treatment. The effects of different zinc acetate concentrations and pressures on chlorophyll color, antioxidant activity, Zn2+ replacement rate, structure, and thermal stability were analyzed. Results showed with increased zinc acetate concentration and pressure, −a* value, antioxidant activity, and Zn2+ replacement rate of samples gradually increased. However, FTIR indicated the structure did not change. HHP fluorescence online analysis showed fluorescence intensity of samples decreased with zinc acetate concentration and pressure increasing. With zinc acetate 10 mg/100 mL and HHP 500 MPa, the highest −a* value (5.19), antioxidant activity (ABTS, DPPH, and FRAP were 37.03 g ACE/100 g, 25.95 g ACE/100 g, 65.43 g TE/100 g DW, respectively), and Zn2+ replacement rate (42.34%) were obtained. Thermal stability of Zn-chlorophyll obtained by synergistic effect was improved significantly.

This study investigated the influence of sweet potato leaf powder (SPLP) (0%–16%) on steamed bread quality. Results showed with the addition of SPLP, height/diameter ratio increased from 0.44 to 0.96, specific volume decreased from 2.44 to 1.47, color changed from white to dark green, and hardness, gumminess, and chewiness ascended gradually; the contents of protein, fat, dietary fiber, minerals, vitamin B2, and niacin increased significantly, in particular, the polyphenol content increased from 1.34 to 9.34 mg chlorogenic acid equivalent/g DW, and the antioxidant activity increased from 1286.08 to 5650.77 μg ascorbic acid equivalent/g DW; the carbohydrate content decreased from 77.60 to 71.50 g/100 g DW, and the estimated glycemic index decreased from 95.25 to 87.51. The steamed breads with 2%–10% SPLP were overall acceptable. In conclusion, adding appropriate quantity of SPLP to wheat flour will not only maintain the technological quality but also improve the nutritional value of steamed bread. Practical applications In recent years, the effective development and utilization of sweet potato leaf (SPL) has become an urgent problem to be solved. The nutritive value of traditional wheat steamed bread are often difficult to meet the daily health needs of human beings. SPL is known to be a rich source of nutrients and bioactive compounds. The application of SPLP in the production of steamed bread is an innovative method with low cost and environmental protection. Therefore, this study aimed to improve the nutritional and functional value of steamed bread by the application of SPLP.