Physicochemical and digestive properties of Lipu taro (Colocasia esculenta (L.) Schott) flour and starch

Summary Lipu taro (Colocasia esculenta (L.) Schott) is a popular tuber crop in China. This study investigated the physicochemical and digestive properties of Lipu taro flour (LTF) and Lipu taro starch (LTS). The results showed that LTF was composed of LTS (79.13%) and non‐starch substances including protein (7.71%), lipid (0.32%), dietary fibre (2.13%), ash (1.05%) and moisture (9.17%). LTF had higher content of enzyme‐resistant starch (ERS, 36.52%) and the anon‐starch substances of protein and dietary fibre can inhibit the activity of digestive enzymes, which led to that LTF had a lower digestive degree during the in vitro gastrointestinal digestion than that of LTS. Moreover, LTS shared similar nutritional compositions including total starch (about 88%) and moisture (about 11%) to the commercial starches including rice, corn and wheat starches (RS, CS and WS, respectively). However, LTS showed the smallest particle size (0.485–7.211 μm) which conferred it the smallest DPn value (16725) compared with other high‐rapidly digestible starches (RDS) of RS and CS. The physical characteristics might have prevented the bonding of LTS to the digestive enzymes, leading to its lower digestive degree than that of RS and CS, and was comparable to the low‐RDS starch of WS. The results suggested that the consumption of LTF and LTS may not induce high glucose levels in human, suggesting Lipu taro is a healthy food. Investigating the physicochemical and digestive properties of the flour and starch of the very special Chinese tuber crop Lipu taro (i.e. LTF and LTS), with commercial rice, corn and wheat starches (RS, CS and WS, respectively) as a comparison.