Pectin – accumulation during winter squash growth and differences among varieties

•Some Cucurbita maxima varieties were good sources of pectin.•Acid soluble pectin (ASP) was the main fraction of pectin in winter squash.•ASP and total pectin originally increased and then decreased during fruit growth.•Species and maturity classes all presented significant effect on total pectin content.

Nineteen winter squash varieties were investigated to improve the understanding of pectic substance accumulation during fruit growth and to explore differences among cultivars. The results showed that there were significant differences in pectin content among varieties (P < 0.05). Some Cucurbita maxima varieties were better sources of pectin, in which total pectin (TP) reached 2.47% of fresh wt. Acid soluble pectin (ASP) was the main fraction of pectin in winter squash, and water soluble pectin (WSP) and oxalate soluble pectin (OSP) were minor components of TP. WSP and OSP increased during fruit growth while ASP and TP first increased and then decreased during fruit growth, peaking at different times for early and mid to late maturity varieties. TP differed between species and maturity classes; TP in C. maxima was about 1.5 times that in C. moschata (P < 0.05). Likewise, TP was 2.3 times higher in early maturity varieties than that in mid to late maturity varieties (P < 0.05).