Impact of packaging material and storage condition on retention of provitamin A carotenoids and xanthophylls in yellow-seeded maize flour

Abstract

Background: Pro-vitamin A carotenoid (pVAC) rich foods are those foods that contain substance which can be converted within the human body into retinol, and which contribute to the reduction of vitamin A deficiency diseases. Yellow-seeded maize flour is an example of such pVAC rich food. Identifying the right packaging materials and storage conditions that retain pVAC in this food is essential for their health benefits. Traditionally, maize flour is stored in different packaging materials to increase its shelf life. For instance, previous studies have shown that during storage in different food matrices, including maize grains, carotenoids are highly susceptible to degradation by temperature, light, and oxygen. The aim of this study is to investigate the effect of storage packaging materials (polypropylene woven sacks-PWS, high-density polyethylene bags-HDPE, and polyvinyl plastic containers-PPC) and storage condition (temperature and relative humidity) on retaining pVAC in yellow-seed maize flour. Methods: The yellow-seeded maize grains were collected and ground into flour. The maize flour was divided into portions (200 g) and each portions was packed and sealed in PWS, HDPE, and PPC. The control samples (12 pieces) were stored on top of the storage box. The packed samples were stored in both the upper (12 samples) and lower (12 samples) compartment of a storage wooden box. The interior of the upper part was lightened with aluminum foil and fitted with fluorescent tube to increase the light intensity, while the lower compartment was darkened with gloss black painting. The flour samples were stored for 28 days, with samples collected for pVAC and xanthophylls analyses at 7 days interval using standard methods. Results: The results showed that packaging in PPC and storing in dark compartment gave the highest total pVAC (92.39%) and total xanthophylls (89.44%) retention, and retinol equivalent (RE) (0.40 μg/g); whereas packaging in HDPE and storing in lighted compartment resulted in the lowest pVAC (44.92%) and total xanthophylls (46.76%) retention, and RE (0.19 μg/g). Conclusions: Packaging yellow-seeded maize flour in PPC and storing in the dark may be recommended for maximum retention of carotenoids in yellow-seeded maize flour since this packaging material and storage condition gave the highest pVAC retention and retinol equivalent.