Impact of packaging material and storage condition on retention of provitamin A carotenoids and xanthophylls in yellow-seeded maize flour
Background: Pro-vitamin A carotenoid (pVAC) rich foods are those foods that contain substance which can be converted within the human body into retinol. These foods also contribute to the reduction of vitamin A deficiency diseases. Yellow-seeded maize flour is a 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 with different packaging materials to increase its shelf life. For example, previous studies have shown how during storage in different food matrices, carotenoids, including maize grains, are highly susceptible to degradation by temperature, light, and oxygen. Therefore, in this study we investigated 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). Each portion 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. The lower compartment was darkened with gloss black painting. The flour samples were stored for 28 days. Samples were collected for pVAC and xanthophylls analyses at 7 day intervals using standard methods.
Results: The results demonstrated how packaging in PPC and storing in a dark compartment resulted in the highest total pVAC (92.39%) and total xanthophylls (89.44%) retention and retinol equivalent (RE) (0.40 µg/g). In contrast, 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, as the packaging material and storage condition resulted in the highest pVAC retention and retinol equivalent.