Orange Flesh Sweet Potato (OFSP)

Objective  

Vitamin A deficiency is a food and nutrition security issue, more specifically in Africa. Orange-fleshed sweet potato (OFSP) root is biofortified with β-carotene, a pro-vitamin A. OFSP is not shelf stable, not available whole year round and current convection oven drying tends to destroy the β-carotene. A microwave and infrared oven were used to dry OFSP slices. The dry slices were milled into flour. The drying kinetics during dehydration and technofunctional properties of flour were determined.  Convention oven and freeze-drying methods were also used for comparison. The aim was to produce OFSP flour with maximum retention of β-carotene content, thus flour can be used as a source of pro-vitamin A. 

Technology Description

OFSP slices were dried for shorter times using microwave and infrared. It took 100 min for infrared alone and 60 min for microwave alone to dry OFSP to < 13% moisture content, respectively. The two technologies (infrared and microwave) were also combined and it took about 45 min to dry the OFSP slices to about 13% moisture content. The combination of the two novel drying technologies helped to produce orange-fleshed sweet potato flour. The flour had high β-carotene retention and minimal colour change as compared to the convective oven drying. The combination treatment showed a retention of about 85.06% compared to 23.61% for the convection oven. The produced flour from different drying technologies was similar to orange-fleshed sweet potato in terms of colour (Figure 1). The low pasting viscosity suggests it can be used as baby food in form of porridge/puree. The orange-fleshed sweet potato flour produced by combining microwave with infrared, can be also used for various food applications. For example, it can be used in bakery for making bread with added nutritional benefits due to high β-carotene content.

CONTACT INFORMATION

Name: Prof MN Emmambux

Address: Department of Consumer and Food Sciences, University of Pretoria

Email: Naushad.emmambux@up.ac.za

Telephone: +27 12 420 2059

Type of partner: University

Name of Institution: University of Pretoria