Effect of cell wall‐disruption processes on wall disruption, antioxidant activity and nutrients in tea pollen
Jizhou Xie, Fang Wei, Liyong Luo, Lifeng Dai, Liang Zeng, Xinghua Wang
Abstract
Abstract Tea pollen is rich in nutritional and bioactive compounds; however, the pollen wall limits their release. In this study, we explored the effects of freeze–thaw processing (FT), a combination of enzymatic hydrolysis and ultrasonication (EHUS) and superfine grinding (SG) on the wall disruption, antioxidant activity, sensory qualities and nutrients in tea pollen. SG‐treated pollen had the highest broken‐wall ratio (100%), followed by EHUS (79.14%), while FT‐treated pollen displayed the lowest ratio (59.86%). Release of nutrient compounds, including polyphenols, flavonoids, carbohydrates, total free amino acids, proteins and theanine, increased after treatment with the three wall‐disruption methods compared with untreated samples. Moreover, levels of epigallocatechin gallate (EGCG), epigallocatechin (EGC), catechin gallate (CG) and gallocatechin gallate (GCG) were higher following EHUS or SG than in untreated or FT‐treated tea pollen. EGCG was the most potent catechin involved in antioxidant activity of tea pollen, making major contributions to the significant improvement of antioxidant activity in SG‐ and EHUS‐treated groups. Additionally, the overall sensory qualities of tea were lower after treatment with the three wall‐disruption methods compared with untreated samples. In summary, SG and EHUS treatment had greater effects on cell wall disruption, nutrient release and antioxidant activity in tea pollen.