Bioaccessibility of beta‐carotene in orange fleshed sweet potato

Abstract

Orange fleshed variety of sweet potatoes (OFSP) was recently shown to alleviate vitamin A deficiency in children in Africa. However, the relationship between β‐carotene (BC) content of different cultivars of OFSP and its bioavailability is unknown. Here, we investigated the bioaccessibility of BC from eight cultivars of boiled OFSP containing different amounts of BC using three phase (oral, gastric and small intestinal) in vitro digestion. All trans BC was the only isomer of BC in cultivars of OFSP with amounts ranging from 112‐281 µg/g in tubers. Boiling OFSP decreased all trans BC content by 11% with generation of 13‐cis BC. The efficiency of BC micellarization was only 0.6‐3% during digestion of boiled OFSP. Addition of soybean oil (2% v/w) to boiled OFSP prior to in vitro digestion more than doubled partitioning of all trans BC in the micelle fraction for all cultivars. The relatively poor bioaccessibility of all trans BC was minimally altered for digestion of 0.5‐4 g OFSP or by increasing the amount of bile salts during digestion, suggesting that the food matrix and not the model system was limiting. Moreover, micellarization of all trans BC from boiled fresh OFSP and commercially processed OFSP was significantly less than that from processed carrots handled identically. Examination of physical form and subcellular localization of BC in the tuber is warranted. Supported by HarvestPlus and OARDC.