Abstract:Using three types of zucchinis（'Biyu' Zucchini,BZ；'Jinpi banana' Zucchini,JZ and 'Moyu' Zucchini,MZ）,this study investigated the differences in their nutrient composition,bioactive substances,and in vitro antioxidant and hypoglycemic activities.The results showed that all three zucchini varieties had high water content（>95%）,low crude fat content（<0.105 g/100 g FW） and total energy（<70.00 kJ/100 g FW）,with moderate crude protein content （0.833-0.945 g/100 g FW）.However,they contained relatively high levels of total carbohydrate and vitamin C,with BZ exhibiting the highest contents at 3.08 g/100 g FW and 12.04 mg AA/100 g FW.Mineral element analysis showed that all three varieties were rich in potassium,phosphorus and calcium,with a relatively high potassium-to-sodium ratio.Amino acid composition analysis showed that all three varieties contained multiple amino acids,with essential amino acids accounting for more than 34% of the total.Fatty acid analysis showed that the BZ had a higher proportion of unsaturated fatty acids （76.84% of total fatty acids）.The contents of total phenols and total flavonoids in BZ were significantly higher than those in the other two varieties.A total of 11 phenolic compounds were isolated and identified from BZ,7 in MZ,and 5 in JZ.Specifically,quercetin-3,4'-dimethyl ether-7-O-rutinoside in BZ was identified for the first time in zucchini.In vitro activity studies showed that the BZ extract had better antioxidant and starch digestive enzyme inhibitory activities.Collectively,zucchini is a nutritious vegetable with low-fat and low-energy.However,there were significant differences in the composition,content,and activity of the components among different zucchini varieties.