Provitamin A carotenoids in biofortified maize and their retention during processing and preparation of South African maize foods

Abstract

Provitamin A-biofortified maize may contribute to alleviating vitamin A deficiency (VAD), in developing countries. However, processing the maize into food products may reduce its provitamin A content. The aims of this study were to determine the composition of provitamin A carotenoids in biofortified maize varieties as well as to assess their retention during processing of popular maize foods consumed in KwaZulu-Natal, South Africa. The non-provitamin A carotenoid, zeaxanthin and the provitamin A carotenoids, β-cryptoxanthin, and trans and cis isomers of β-carotene, and other unidentified trans and cis isomers of β-carotene were detected in varying concentrations in the maize. Milling provitamin A-biofortified maize into mealie meal resulted in a higher retention of carotenoids compared to milling into samp. The highest retention of provitamin A carotenoids was observed in cooked phutu and cooked samp, whilst cooking into thin porridge resulted in the lowest retention of provitamin A carotenoids. In phutu, 96.6 ± 20.3% β-cryptoxanthin and 95.5 ± 13.6% of the β-carotene were retained after cooking. In samp, 91.9 ± 12.0% β-cryptoxanthin and 100.1 ± 8.8% β-carotene; and in thin porridge, 65.8 ± 4.6% β-cryptoxanthin and 74.7 ± 3.0% β-carotene were retained after cooking. This study demonstrates that provitamin A retention in maize is affected by the cooking method (and hence cooked food form) and therefore cooking methods that result in a good retention of provitamin A need to be identified and recommended.

Carotenoid Retention of Biofortified Provitamin A Maize (Zea mays L.) after Zambian Traditional Methods of Milling, Cooking and Storage

“…Most of the carotenoids were retained during this process except for β-cryptoxanthin, which showed a consistent 60% retention across all genotypes (Table 3). These findings were contrary to those reported by Pillay et al, 9 where a higher retention of β-cryptoxanthin (95.3−113.5%) was observed in milled maize. Different maize genotypes and milling processes could be a source of variation with reported studies.…”

Micronutrient (provitamin A and iron/zinc) retention in biofortified crops

“…For cooked products, the retention varies depending on the type of cooking. For traditional cooked dough (Phutu) the retention of provitamin A carotenoids was between 107 and 118% as found by Pillay et al [21]. Fried products generally presented a higher degree of degradation, whereas boiled products presented better retention.…”

“…During both milling and processing, biofortified maize hybrids showed good levels of retention of provitamin A carotenoids when using apparent retention values [21]. The retention values were measured between 105 and 137% in maize meal and samp, respectively.…”

Accruing genetic gain in pro-vitamin A enrichment from harnessing diverse maize germplasm

“…Some of the promising lines had high provitamin A content by accumulating mainly higher levels of b-carotene at the expense of the synthesis of other carotenoids while others contained high provitamin A by accumulating high levels of both carotenes and xanthophylls. These lines will be useful not only for the development of hybrids and synthetics with high concentration of carotens and xanthopylls but also for elucidating the mechanisms that regulate the synthesis of more substrates upstream in the carotenoid biosynthetic pathway and the resulting increased flux downstream Table 3 Provitamin A contenet and grain yields of the best five synthetic varieties (OPV) and hybrids selected from each of the two regional trials evaluated at four to six locations in 2013, 2014 and 2015 Even though significant progress has been made in boosting provitamin A to higher levels in tropical maize, studies have demonstrated that the loss in provitamin A during storage, milling, and preparation of diverse traditional foods may reach up to 70% (Muzhingi et al 2008;Mugode et al 2014;Pillay et al 2014;De Moura et al 2015). Also, the extent of loss in provitamin A carotenoids exhibits a broad range of variation among maize genotypes in these studies.…”