Polypropylene-based packaging materials for shelf-life enhancement of yellow corn (Zea mays) kernels: Effects on lutein, aflatoxin content, sensory, and nutritional profiles

Abstract

Yellow corn (Zea mays) kernels were packaged in unilamellar polypropylene (PP), bilamellar PP/PET (polyethylene terephthalate), and trilamellar PP/PET/Al (aluminium foil) composite and stored at ambient conditions (23 ± 2 °C, 80% RH) for the extension of their shelf‐lives. Lutein content, aflatoxin content, sensory, physicochemical, phytochemical, and nutritional properties were adjudged. X‐ray diffraction, thermogravimetric‐differential thermal analyses, differential scanning calorimetry, and percentage opacity of the three packaging composites revealed that among the three combinations investigated, PP/PET/Al composite possessed highest crystallinity, thermal stability, and percentage opacity, thereby exhibiting improved barrier properties against moisture, gas, and light. These attributes led to enhanced carotenogenesis and minimal aflatoxin content, conferring highest shelf‐life of 90 days to the trilamellate packaged corn kernels, compared to PP‐ and PP/PET‐packaged samples (60 days). Sensory, physicochemical, phytochemical, and nutritional profiles were also best retained in the same compared to PP‐ and PP/PET‐packaged and control corn grits. Practical applications Corn is one of the major cereal crops consumed worldwide. Besides its nutritive value, it is also a good source of the nutraceutical “lutein.” Therefore, to meet the demand of the food processing industries and consumers, the grains must be preserved well. The current approach of application of non‐thermal preservation technology viz. “packaging” (using commercially viable, flexible packaging materials) could well preserve lutein as well as sensory attributes, phytochemical properties and nutritional constituents of the corn grits, when stored at ambient conditions (23 ± 2 °C, 80% RH).

Gamma irradiation of trilamellate packaged yellow corn ( Zea mays ) kernels enhances lutein content and shelf life

“…In an earlier study, we have obtained maximum carotenogenesis in 60‐day stored PP/PET/Al‐packaged corn grits, in which lutein content had reached 245 ± 1.70 µg/100 g corn grits (dry basis [d.b. ]; Pal & Bhattacharjee, 2018). In the current work, the lutein content was found to be 17.22% greater (296 ± 1.86 µg/100 g corn grits [d.b.])…”

“…PP/PET/Al laminate pouches of dimensions 0.16 × 0.12 m and thickness 110 µm (previously optimized packaging material for the extension of shelf life of yellow corn grits under ambient storage conditions; Pal & Bhattacharjee, 2018) were purchased from M/s Trinity Packaging, Kolkata, India. Lutein (xanthophyll, X6250), “Aflatoxin Mix 4 solution” consisting of aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1) and G2 (AFG2), and 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) were purchased from M/s Sigma, St. Louis, USA.…”

“…The irradiated and non‐irradiated corn grit samples were also analyzed for their sensory attributes such as overall appearance, color, odor, texture, taste, and aftertaste; physicochemical and phytochemical properties such as color profile ( L *, a *, b * values), total phenol contents (TPC), antioxidant activities (by assaying ferric reducing antioxidant power [FRAP] values and IC 50 values of DPPH radical scavenging activities [DPPH‐RSA] of the phenolic extracts and by electron paramagnetic resonance [EPR] spectroscopy analyses of lutein‐rich extracts of yellow corn kernels) and nutritional profiles (proximate constituents) namely moisture, lipid, protein, and reducing sugar contents, in accordance with the methods that have been adopted for ascertaining the shelf lives of yellow corn kernels by flexible packaging (Pal & Bhattacharjee, 2018). The γ‐irradiation dose that conferred highest shelf life to the packaged‐irradiated corn kernels was selected as the best dose.…”

“…Use of 3‐ply flexible packaging laminate, namely, polypropylene (PP)/polyethylene terephthalate (PET)/aluminium (Al) foil laminate could successfully extend shelf lives of yellow corn kernels 60 days more under ambient storage conditions (23 ± 2ºC, 80% R.H) vis‐à‐vis their non‐packaged counterparts (Pal & Bhattacharjee, 2018). Considering the need for this cereal crop all year around, the present work envisages employing the combination technology of flexible packaging and γ‐irradiation in preserving the nutraceutical properties of corn grits without compromising their sensory attributes.…”

“…Besides increasing shelf life, γ‐irradiation (at certain doses) is also hypothesized to enhance carotenogenesis (enhanced production of lutein) in the packaged‐irradiated yellow corn kernels during storage, since it is reportedly known that γ‐irradiation produces excess reactive oxygen species (ROS) during senescence, which may trigger the carotenoid (antioxidant) defence mechanism of the corn grit cells against oxidative stress (Fanciullino, Bidel, & Urban, 2014; Pal & Bhattacharjee, 2018). The specific objective of this study was to select the best dose of γ‐irradiation for the extension of shelf life of packaged (PP/PET/Al) yellow corn kernels primarily on the basis of changes in their lutein contents and aflatoxin (if produced) contents during storage under ambient conditions.…”